Fast RC

X3.5 Ready to go...

2011-11-18T11:05:00.001-06:00

New car ready to take out and stretch its legs.

X2 update-new batteries

2009-06-01T18:30:00.006-05:00

Its been a while since I updated, but I've been moving into a new house. I'm just about all setup with my new workshop.

My old Thunder Power 4s 3300 mah 25c batteries were getting old and I needed to replace them. I just got in three brand new Thunder Power 3200 mah 4s 40c batteries. I will be able to use these 3 packs on the X3 and X5.

I will be testing in the next couple weeks and I'll post my updates as soon as I get some data.

X5: new gears

2009-03-24T21:07:00.003-06:00

Its been a while since I have updated the site, but I am still working hard on my cars. I have installed steel gears on the X5 to help reduce the chances that I will destroy a set of gears on my next run. I am also getting a new set of Thunder Power 12s 40c 3200 batteries for my next test session.

I am currently in the process of buying a new house. My wife and I should be moved in the next couple weeks and I should be able to test again.

I've also put together a new set of tires for the X2. These tires are based on a 1/8 scale on road tire and are much harder than the drag racing tire I have been using. I will test these new tires on the X2 next time I go out testing. Stay tuned!

Video: X2 hits 97 mph

2008-12-11T23:49:00.005-06:00

I tested the X2 on November 30th and had some really good luck with the car. I limited the center shock travel so the motor plate wouldn't scrape the ground. I managed 97 mph on 8s. Everything went well except the very high winds we encountered that day. You will notice in the video that I was driving the X2 in the opposite direction that its usually run. The wind was either a cross wind or a head wind. I think the wind had something to do with the speeds that day.

I was doing a couple test passes when I did the 97 mph pass. Unfortunately the video equipment didn't catch the 97 mph run. Once the equipment was running, I did some more passes but could not get another 97 mph run. The next 4-5 passes were all at about 91-92 mph.

I am planning to test this weekend weather permitting. I am going to step up to 12s. I am also going to reduce the upsweep of the rear end of the body to reduce some downforce and drag. I am hoping for some triple digits. The layout of the car is similar to what I ran at Rockingham on 12s:

X2 testing - 89 mph

2008-11-12T20:59:00.006-06:00

X2 ready to go with some extra lexan added to the front for more downforce.

Bottom of the front end. The X2 was getting so much extra front end downforce, it was scraping against the concrete during hard braking.

I had great success using this clear lexan body at the ISC event at Rockingham. I hit 86 mph running the X2 front wheel drive before I blew a tire. I figured that If I can get some more downforce on the front end I could reach higher speeds before the tires blow. I cut a piece of lexan to extend over the front of the car by about an inch and the sides about an inch. This increased the front area and therefore increased the downforce. I was happy with the results. I hit 89 mph and the car felt nice and stable. I need considerably more run up room for the front wheel drive X2 than I do for the 4wd drive X5 and X3. The only problems I ran into was the bottom of the front end scraping the ground and wearing away the screws used for the motor mounts. For the next outing, I'm going to modify the suspension so the motor mount plate will stay level to the ground and not scrape the ground. I'm shooting for 100mph for the next testing session.

X5 testing

2008-11-06T22:06:00.003-06:00

Stripped gears after 4 runs

Data from the entire session.

Fastest run of the day, 86 mph.

I tested the X5 this past Sunday. I was ready to go out and get over 100mph, but I had the same problem I had in N.C. I stripped the gears. I thought I had the mesh set correctly, but I think its too loose. I have a new set of gears ordered but I dont think I'll get them by this weekend. My plan for this weekend is to test the X2 front wheel drive with the same body I used in N.C.

X5

2008-10-26T12:25:00.006-06:00

X5 making a pass at the ISC event at Rockingham dragway. I was able to only make one pass before the gears disintegrated.

I've started putting together the X5 for testing on 12s. Here are a couple pictures of the car and I also posted a picture of eagle tree data with a motor temp sensor and GPS. I took it for a short run to make sure everything was buttoned up. I plan to get out next weekend and do some high speed testing.

Results from the 2008 R/C Speed Challenge

2008-10-07T18:15:00.023-05:00

Getting ready for the first test run of the day with the X-2
X-2 on 12s. I ran it both forward and backward at the event. I made the fastest pass of the day of 85 mph on 8s. I then tried running on 12s and I think the speed control hit the low voltage cutoff and didn't deliver power during the 12s run.
X-3 didn't get a chance to run. I spent too much time fixing my transmitter to run the X-3.
This is the X-5. It might look familiar to people who are into speed run cars...
Setting up the X-5 for a run. I broke my Futaba 3PM 2.4 Ghz so I used my 15 year old Futaba 3PB 27 Mhz.
Trying to fix my transmitter after I dropped it. Take a look at the nice "McGyvering" of the antenna with a coat hanger and some duct tape. After this picture was taken I went to test the setup and I only had about 30' of range. I took apart the amplifier and found the PC solder joints were broken. They were too small to fix out in the field. This is the point at the event I had to go with my backup transmitter.
Buttoning up the body on the X-2 for a rear wheel drive run
X-2, X-3, X-5 ready for some speed.
X-2 and the bodies I used for the X-2. I ran the white body for rear wheel drive runs and I used the clear lexan body for front wheel drive runs. My fastest run for the day was 85 mph with the clear body on the X-2.
This is the X-5. It is a highly modified Team Associated TC4 built by Matt Shumaker. He also made the lexan body and the carbon fiber body.

X-2 making a run down the Rockingham track
X-5 making a pass. Fastest run with this car was 79 mph.
All my speeds for the event. Allison was a great help by recording all the runs.

The first car I ran at the event was the x-2. I started off running it rear wheel drive. The X-2 felt like it was on ice. It was difficult to put the power down but I managed to get 61.93 mph on the first run.

Then I ran the X-5 and managed 79 on the first run. Then on the second run of the X-5 I felt slipping in the transmission. I brought it back to the pits and I had stripped the pinion and spur gears. I didn't have a backup set of gears so that car was done for the day.

Then I decided to try the X-2 backwards with the lexan clear body. On the first run I got 85 mph on 8s. Thats when I decided to up the power to 12s. During that run it felt like either the tires were slipping or the speed control hit the low voltage cutoff. It seemed to drop off in power halfway through the run. I coasted through the trap at 64 mph. I brought the X-2 back to the pits and noticed that the tires had some tire wear on the insides of the tires. It looked like the tires were expanding so much that they were hitting the suspension mounts. So it seems as if I had so much power that the tires were spinning and expanding so much that they were wearing themselves out. This is why it felt like it was slowing down during the run on 12s.

Tire wear from rubbing the suspension mounts while on 12s.

Overall I had a great time. I got to meet everyone and see the projects that I have only seen online. I was disappointed with my performance. I wish I had more time to make some runs with the X-3. I knew I could have gotten some great speeds with that car on 12s. The X-2 still has a ton of potential but I need to do more testing with different bodies. The X-5 also has a ton of potential and I look forward to testing that soon.

Heading out to the 2008 R/C Speed Challenge

2008-10-02T23:35:00.002-05:00

Its been a while since I have posted. I have been trying to get some work done on the X-3 and X-2 in the last couple weeks. We had some damage to the house when hurricane Ike came through and had to take care of the mess. All my cars are packed and I am heading out to Rockingham early tomorrow morning. I am looking forward to meeting Nic Case and Gary and all the other guys that are coming out to run. It will be a great time. I will take as many pics and video as possible and post updates as soon as I can. Wish me luck!

X2 Testing (8-3-08). Another blowout.

2008-08-14T20:41:00.008-05:00

First set of tires tested

Tires worn down to their minimum diameter after only 5 runs

Second set of tires exploded at 72 mph

Tire carnage all over the track

Click on video above then click on "watch in high quality"

In this testing session I tried 2 sets of tires. The first set of tires had foam cut from a large piece of stock foam. Then I glued the foam onto the custom aluminum rims that my father machined. Then I trued down the diameter of the foam from 4.5 inch to 3.5 inches. The second set of tires are based on the stock foam tires that come in the OFNA Ultra GTP kit. The only thing I did was true down the diameter from 4 inches to 3.5 inches. Then I modified the center of the rim to accept the 1/10th scale clamp style hub.

I first tested the aluminum tires. I ran these tires for about 5 passes. After each pass I would check the diameter of the tire. It was apparent that the foam I used for the aluminum rims was wearing out very fast. Sunny said that as the X2 passed by, he could see tire dust billowing from the sides of the car. Within 5 runs the tire diameter went from 3.5" to about 3.25". The minimum diameter I can run is about 3.25" before the chassis starts to hit the ground. These tires worked very well and held together for a pass with a max speed of about 70 mph. The problem that I am seeing is that on that 70 mph pass, I was using 100% throttle. With 30 V at a KV of 480 that is an rpm of 14440. That should be a speed of 110mph. There is obviously serious wheel spin.

The second set started out very well. But after I made more passes and increasing throttle, the tires exploded. The same thing happened as with the first set, I was giving the X2 full throttle and the tires were spinning at a much higher rate than what the car was traveling.

It looks like I am going to put the X2 on standby for now. I am going to concentrate on the X3 for the International Speed Competition in October. I am working on getting a 12s battery setup. The X3 has been performing very well and I am going to be shooting for 100mph on the 12s setup. Check back for details on the X3.

X2 is back

2008-07-27T20:33:00.015-05:00

I have been working on some changes for the X2 while I have been testing the X3. This past Saturday, I tested some new wheels. These wheels were taken from the OFNA Ultra GTP and I modified them to accept 1/10 scale clamping hubs. Then I trued the tires down to 3.5" in diameter from 4".

Here are some videos of the X2 doing some low speed passes from this Saturdays testing:

Some people have mentioned to me the reason why I have been blowing up tires is from all the sprung weight of the motor within the suspension. I do agree with this. But I have to wonder if the problem is still the design of the car, or a problem with the tires. If you take a look at Nic Case's prototype from last year, you can see that neither the front end or rear end has suspension:

Nic was supposedly able to reach 130mph with this car and his wheels are half the diameter of my tires. So it seems like the tires aren't the limiting factor in these high speed r/c cars. I will still be working on the X2 as my main car for the high speed event, but the X3 will be a backup. I will be doing some more testing with different tires and I will post my progress here.

The International R/C Speed Challenge - presented by Castle

2008-07-25T00:03:00.001-05:00

International R/C Speed Challenge-Presented by Castle
Is happening this year Oct 4th @ the Birthplace of Nascar
We will use ROSSA rules & DUAL Optical Speed traps.
There are plenty of classes for everyone
How Fast is your car? – Prove it to the World
Rockingham Dragway is a First Class facility.- Billy Weeks is the race director
*******Extreme R/C & R/C Driver will be covering the event!*******
---other magazines welcome---

The "International Speed Cup" is for the over-all fastest speed in the world! It’s a perpetual Award---(Similar to a Stanley Cup)------ Starting at the UK event ------ and if us Americans can TOP the Britt's speed------ the "International Speed Cup" comes to the United States!---
only the fastest driver in the world will ever possess the “Cup”

There will be a 100 mph club -----You will receive a special embroidered hat for everyone that breaks the century mark!

This event qualifies for the Guinness Book of World Records.

Be a part of History; feel the need--- the NEED FOR SPEED!

Entry Form

R/C Speed Challenge 2008 Officially announced! October 4th at Rockinham N.C. - Sponsored by Castle Creations

2008-07-20T00:25:00.002-05:00

The 2008 R/C Speed Challenge has been officially announced. It will be hosted at Rockingham Dragway in North Carolina October 4th 2008. It is sponsored by Castle Creations. Click the Castle logo above to get more information about the event. Details are still being ironed out, but the event will happen this year.

This is what Nic Case said about the event:

Hi Guys

Yes-- the cat is out of the bag.......We will have a speed run in the United States-- on Oct 4th!
We will use ROSSA rules & an Optical Speed trap. This is going to be a blast!
I understand North Carolina is very nice in Oct.
We have a lot of support from sponsors. Thanks to Billy Weeks for handling the race director/Promoter duties...

Special thanks to Tony Lovering (aka AJ/ziggy 12345) for having this site & being the founder of ROSSA...!

R/C Driver has committed to a 2 page article
Extreme R/C is interested

We will have an "International Cup" for the over-all fastest speed ---- Starting at the UK event –
-- and if us Americans can beat the Britt's speed--------- the "International Cup" comes to the USA!

There will be a 100 mph club ------- A special embroidered hat for everyone that breaks the century mark.

We are in the process of getting the details for the "Flyer"------ so, stay tuned.

Speed is Cool
N

More information can be found here.

Testing results from 7-12-08. 83 mph. Motor problems

2008-07-19T16:02:00.020-05:00

What the motor should look like

After doing some high speed runs. The motor endbell has slid off.

This post is a week late since I've been pretty busy lately. But I wasn't able to get any faster than 83mph. I made some changes since the last testing session. I removed all the data logging equipment, I modified the body and I removed the heavy stainless steel gear and replaced it with a lightweight delrin gear.

After doing the last pass of the test session, I noticed the power of the motor decreasing. I removed the body and I took a look at the motor and I noticed the end of the can was sliding off. It came loose during the runs. You can see this in the second picture of the motor. It has come off about 5mm from where it should be. Neu Motors has addressed this problem with their newer motors and has secured the endbell with screws like the motor below (the pic is a Neu 1515 but I will need this on my 2215):

I am going to have to send the motor back to Neu to get it repaired. I think this is the problem with not being able to get a higher speed. I should be able to reach at least 90 mph on 8s.

No testing this past weekend

2008-07-02T00:09:00.008-05:00

Latest pics of the X3. We didn't get a chance to do some speed runs. We got kicked out of the parking lot area before we could get setup.

I've made some modifications since the last testing session. I removed the data logging equipment and switched to a 2s 800 mAh li-po receiver battery from the heavy 1400 mAh ni-mh pack. I think I took off about a pound of extra gear. I also changed the old stainless steel gear for the delrin gear. This delrin gear is about 1/3 the weight of the stainless steel.

We're still looking for some more room to run. The X3 is ready for a 100% full throttle pass. Its been trimmed as much as it can get for now. We might have to go back to the usual testing spot and what speeds we can get there.

In the parking lot trying to get a run in before we get kicked out. Here is (L to R) Trey with his Rustler, Sunny with his Rustler and my X3 in front

Latest iteration of the X3. All data logging equipment removed and ready for a 100% full throttle pass. Just need some more room to run

New lightweight delrin gear replacing the heavy stainless steel gear

Worn out stainless steel gear

Testing today-83 mph

2008-06-22T22:40:00.008-05:00

Data from the 83 mph run.

Video of the 83 mph runs.

This post is a little late since Blogger was down for a while. This is from Sunday's test session. I was able to hit 83 mph. This was a bit of a disappointment. I was hoping to get at least 90 mph. I believe the next test session I will have to remove all the data logging equipment that can be a source of a lot of resistance in the power system. Another problem is that we are running out of room to get the cars up to speed and to slow down. I think a new spot has been found in the parking lot of a mall outside of Houston.

Possible new location for testing. At least 1500' of test space.

Test location we have been using for the past couple months. Only about 700' of running space.

More detailed data from the 81 mph run

2008-06-17T23:12:00.003-05:00

I added watts to this graph and I also changed the left axis to show more details on the RPM.

X3 testing today - 81 mph

2008-06-15T19:49:00.008-05:00

Today's testing went very well. I was able to get my Eagle Tree eLogger V3 working with the 5Hz GPS module. I wanted to be able to get data on amps, volts, watts, speed and motor rpm. There are a couple interesting things to point out about the data. If you take a look at the detail of the 81mph run data, you can see that the GPS measured a max of 77.7 mph. The radar measured 81 mph. As far as I know the GPS is more accurate in speed (.1 knot) compared to the radar. But since just about every one who is doing these r/c speed runs is using the same type of radar, and I have been using the same radar since I started I will say 81 mph is the max speed reached in this testing session.

I also tried some belted rubber tires instead of the foam tires I have been using since I got this car. They worked very well and they felt like they had more traction than the foams. The problem is that they are slightly smaller in diameter than the foams. This means with the same gear ratio, I will go slower with the rubber tires than the foams because of this smaller diameter.

Since the accident with Greg's leg last week, I reinstalled the vertical stabalizers. These are a huge help at high speeds. The importance cannot be stressed enough. The car feels like its on ice without the vertical stabalizers. They make driving the car much easier and controllable. There was no evidence that blowover was going to happen at these speeds so higher speeds can be tried next session. We are going to have to increase our space were we use to test. The run up area has plenty of room, but the slowdown part of the testing track is getting too short with these higher speeds. We're going to have to move down the track into the "prepared" surface of the drag racing track. This will cause some problems during the runs when the driving surface transitions from the prepared surface to the bare concrete of the shutown area. Hopefully it wont become an issue. We will find out during our next session.

The "X3" should be able to reach into the 90's with this setup on 8s. As soon as I can reach the limits of this 8s setup, I will upgrade to 12s and push the limits of that setup. Since this last weekend of testing, the car feels nice and stable and I will be able to punch it 100%. Check back soon for details.

X3 testing today-Ran into Greg's leg at 76 mph

2008-06-08T20:51:00.004-05:00

I went testing today and made some changes from my last 79 mph run from last week. I needed to get more downforce on the front end to keep the X3 from blowing over. The lexan splitter I added underneath the front bumper definitely helped out but I could still see the car about to blowover around 80mph. I added winglets on the sides of the front to add extra downforce. I also wanted to reduce drag so I removed the spoiler from the rear. I felt like I was getting enough traction so I didn't need the downforce created by the spoiler. But removing the spoiler also reduced stability of the rear vertical stabilizers. I had done some test runs with this new configuration and I encountered significant flutter from the vertical stabilizers at high speed so I removed them. But as you can tell from the changes that I made I would create more front traction and loose lateral stability. This is exactly what happened on this run. The front end was too twitchy and the rear end was very loose. But on the positive side, the car was much faster with the same amount of throttle input as the 79mph run.

You can see in the video that the X3 had changed directions a couple times during the run, but was too close to the center of the track where Greg was filming and the radar gun was setup. I tried to correct but it wasn't quick enough to get out of the way of Greg and the radar gun. At the point in the video where you cant see the X3 is when Greg attempted to get out of the way. The X3's front left side took out the radar gun tripod at 76 mph, caught air, hit Greg's leg and flipped before landing on its wheels 20 feet away. The pictures above are after the accident. I checked over the X3 and I had to tighten some set-screws and she seems Ok.

The importance of the vertical stabalizers can been seen in the slow motion of the video. My next step is to modify the body so I can reduce some drag and add larger vertical stabilizers. Other than that, the car is setup very well. It feels and handles great besides the aerodynamic characteristics. With the X3 on 8s geared 64 pinion 36 spur the calculated top speed is around 95 mph. This is target speed for the X3 with this setup. After I reach around 90 mph I want to change to 12s and really push the envelope of that setup.

X3 Testing today - 79 mph

2008-05-31T20:32:00.007-05:00

stainless steel pinion gear teeth wearing out

Today went well. Since my last testing day I had changed the suspension to get the chassis so the front was lower than the rear to try to resist blow over. I also attached a splitter to the front end to help create down force. This did help as I was able to go faster without blow over. But, I was able to see blow over about to happen at around 79mph. I had to back off the throttle to make sure the X3 didn't take flight. It looks as though the X3 still wants to blow over even with the front splitter and the suspension changes. I want to modify the front end some more to apply more down force and change the rear end to reduce down force and drag.

The data recorder didn't work. It was unfortunate that I wasn't able to get data from my Eagle Tree recorder.

I have some aerodynamic changes to make to keep the X3 from blowing over and I will be out testing again.

Blow over in slow motion

2008-05-19T12:23:00.001-05:00

X3 Testing today

2008-05-18T14:11:00.010-05:00

The weather was much better today and I got a chance to test. Max speed today was 73mph at about half throttle. After the 73mph pass I made another pass with more throttle than the previous runs. At about 75mph the X3 blew over.

Video of 73 mph pass

Data from 73mph pass

Video of blow over pass at about 75mph

Data from blow over pass

Damage to the X3 from the blow over

The rear springs are much too soft for the extra weight of the massive motor and batteries. Stiffer springs are necessary to maintain a good rear ride height. Under acceleration the back end would squat and the positive angle of the chassis would direct all the airflow underneath the car. This caused lift and I had a blow over. I tried to minimize the up-travel of the rear shocks with spacers, but then the rear shocks would rest on the spacers and that rendered the suspension useless since there was no upward suspension travel. I also need to decrease downforce on the rear of the car. I need to trim or get rid of the rear wing. As far as I can tell the damage to the X3 is superficial. The body and front right wheel seemed to absorb most of the impact.

Overall, I am very happy with how testing went today (except for the blow over). The X3 felt very stable and very easy to drive. Acceleration was excellent. I didn't push the X3 to its limits because the spur and pinion gears are wearing themselves out very fast. I need to get a new set after the next couple runs.

I will make a couple of changes and I will be back testing soon.

Rained out

2008-05-17T13:46:00.008-05:00

Well, today was rained out, but it looks like the weather should be better tomorrow. I'm hoping we'll have nice weather to get a go at some good speed runs. In the meantime, I have taken some pics of the current iteration of the X3:

Some changes since the last pictures I posted are that I added some Lexan side body supports to help stabilize the body at high speeds. I installed the gyro up front in the foam bumper. I also cut the rear section out of the body to help any air flow through and out the back. I also installed large vertical stabilizers to keep the X3 from fishtailing at high speeds.

The X3 is ready to go for tomorrow.

Update

2008-05-15T23:06:00.008-05:00

Quick update. I have everything installed and the body is mounted. The "X3" is ready to go for testing this Saturday weather permitting. I will be running:

Batteries: Thunder Power 3300mah 8s (4s+4s)
Gearing: 32p gears-64 tooth pinion, 36 tooth spur (chart below says 32).
Futaba GY401 Gyro installed
ESC: Castle Creations HV-110

This is a quick video of the X3 doing some slow passes in the street.

Here is the data from the Eagle Tree during that run:

Second run (more aggresive on the throttle than first run):
The biggest amp draw on that run was about 90 amps at 50% throttle. I was able to hit about 50mph without a sweat.

The X3 felt good and stable. The 4wd drive is a definite bonus over the FWD of the X2. The acceleration is explosive and I can still break the tires loose even with this car geared at 64 tooth pinion and a 36 tooth spur! The NEU 2215/3Y is a monster. My plan is to get around 100mph on 8s:

The only thing I am worrying about is the pinion gear keeping a tight fit on the motor shaft. The pinion has already rotated about the motor shaft and the set screw is no longer on the flat part of the motor shaft, but it has not come loose with all of the driving I have done so far.

I am looking forward to posting some good speeds. Its about time to make some serious progress with all of the power I have available. The X3 can deliver all this power to the ground.

X3 body

2008-04-27T15:40:00.003-05:00

X3 Update

2008-04-26T20:44:00.005-05:00

Its been a while since I updated. Here is the status of the X3 so far. Everything is installed. The motor mount looks and works well. My father made the prototype mount for the Neu 2215/3Y. You can see the gearing looks very radical. This is because the low KV of the motor. Its only 480 Kv. So I need a large ratio to get as close to a final ratio of 1:1 as I can. Right now it is a 32 pitch 64 tooth pinion and a 36 tooth spur.

I've done a couple low speed passes on the street in front of my house and the only problem I see is that the pinion gear is not locking into place like it should with the setscrew. It comes loose after only a few passes. I removed the pinion and I noticed that the metal on the shaft of the motor where the setscrew would tighten down is dented. I think the steel on the motor shaft is too soft. It isn't hardened steel. If this is the case I will need to take it back to Neu to get a hardened steel shaft. This will make sure the pinion gear doesn't come loose. But this will also set back my testing schedule a couple weeks. I am going to file down the flat in the motor shaft a little more to see if I can fix the problem.

I made a quick video of the X3 doing some low speed testing in front of my house. The X3 sounds loud. I didn't expect it to be that loud. I am using stainless steel gears after all. I apologize for the angle of the video. I got a new camera and it wasn't setup to record properly.

New car - The "X3"

2008-03-25T16:57:00.014-06:00

Well, if you guys have been following my progress you have seen that I have been having some bad luck with my car. I have been disappointed with myself that I haven't reached the speeds that I wanted. The heavy motor in the suspension system doesn't allow the shocks to compensate fast enough for the rough surface. I believe that is why my wheels would keep blowing. Too much sprung weight. I have been thinking of a new car to use. I have decided on an OFNA Ultra GTP. It is a 4wd shaft drive 1/8 scale gas buggy. I am going to convert it to fit the Neu 2215. This car is much heavier, but much beefier. It should be able to handle the 7hp (5000 Watt) Neu 2215. I already have the car and I started to layout the electronics. I am calling it "X3". I have designed the motor mount and it is being fabricated now.

"X3" This is the initial layout of the components. It is messy because its not permanent. I want to be able to move the electronics around until I find the best placement.

"X3"

"X2" on top, "X3" on the bottom

"X2" is on the back burner...for now.

"X2" in its last testing interation

I am not completely abandoning the "X2" design. I know it has a lot of potential but for now it requires too much tweaking to attain the speeds I would like in the time frame given. I am putting it on the back burner for now and I will return to it in the future.

Testing today - another blowout!

2008-02-23T17:13:00.011-06:00

Carnage from tire failure
Closeup of damage
Data from fastest passes of session 1
Data from fastest passes of session 2
Data from tire blow out pass.

Pass 1

Pass 2

Pass 3

Radar pass 1

Radar pass 2

Radar pass 3

Blowout

Well, I had some higher speeds today and good traction. But I also had a tire explode. This is exactly what I wanted to fix since this happened last July. This is why I made my own tire. The way this new tire failed is exactly how the last tires failed. The X2 even made the same sound right before the wheel exploded.

I do have another set of tires that I custom made that might work . These wheels are a solid piece of aluminum with a setscrew to hold onto the motorshaft. They dont use hubs. I want to try these out next testing session.

Im not sure why this failure is happening. I dont know if the tire is out of balance. I made sure to accurately balance these tires.

Testing today - better traction

2008-02-18T11:23:00.006-06:00

X2 testing on 2-17-08

X2 Testing 2-17-08 video 2
This picture shows the locations of testing on 2-9 and 2-17. Running on the drag racing surface was very slick for foam tires. Running on the bare concrete in the shutdown area yielded much greater traction.

Pass 1

Pass 2 and 3

Pass 3 and 4

Pass 5 and 6

Sunny and I went to Houston Motorsport Park to do some more testing. This time we did our testing on the shutdown area of the 1/8 mile track. The shutdown area wasn't covered in rubber and VHT. It was found that the drag racing surface too slick and yielded no traction. The concrete surface yielded much more traction. I was able to get a few runs in to hit about 50 mph. I didn't push the X2 too much. We ran out of time for testing this day so next time I can push the X2 even further.

Testing today - no traction

2008-02-09T18:37:00.001-06:00

Data from pass 1

Data from pass 2

Data from pass 3

Data from pass 4

href="http://video.google.com/googleplayer.swf?docId=-3094208979123285630&hl=en">

Rudder system and steering system with gyro stabilization.

My friend Sunny and I went out to Houston Motorsport park (1/8 mile course)to do some high speed testing. It was a disappointing day. There wasn't any traction to be found on the drag track. When you watch the videos you can hear the wheels just spinning and not getting traction. A new location needs to be found for further testing. My car gets much more traction on regular asphalt or concrete. These new tires are a much harder compound than the soft drag foams I was using.

Boycott Dymond

2008-01-17T18:24:00.001-06:00

It has come to my attention that Helmut Goestl of Dymond Modelsport has a class action lawsuit against Castle Creations and Thunder Power batteries.

These two great companies, Thunder Power and Castle Creations are my sponsors. The have supplied me with components that work flawlessly during my testing.

The class action suit has to do with Mr. Goestl saying that Castle Creations products and Thunder Power products aren't made in the USA. They represent the best of American technology. I support Castle and Thunder Power 100%. Please do Castle Creations, Thunder Power and myself a favor and boycott Dymond Modelsport and anything Mr. Goestl is associated with. Read the links in this article to get the whole story. Thanks for everyone's support.

New wheels installed, "X2" ready for high speed testing

2007-12-27T16:06:00.000-06:00

"X2" with new wheels installed

These new wheels are now the correct diameter and trued for high speed running.

New wheel on the left, old wheel on the right. You can see there is much less sidewall of foam. Hopefully this will reduce the likelihood that the foam will fly off the rim. The new aluminum wheels are much heavier than the plastic ones, but they are much stronger.

Data from a slow speed test using new wheels. High speed for this run about 28 mph.

Weight of "X2" with all electronics installed except for the body, 6 lbs 8 oz.

More wheel designs

2007-12-11T19:39:00.001-06:00

All wheel designs to be tested in the next high speed run.

On the left is the 1/8 scale on road based wheel and on the right is a much larger OFNA style on road wheel. The OFNA based wheel has a much larger inside diameter and outside diameter. The idea with the OFNA based wheel is to minimize the sidewall size of the wheel while keeping the outside diameter close to 3.25". The tire needs to be trued down to correct size. You can also see that a hub isn't used to attach the wheel to the motor shaft. Instead a mount using setscrews is used to tighten the wheel on the motor shaft.

Wing design

2007-11-16T22:24:00.000-06:00

From my initial calculations, I need to get downforce on the front drive wheels in order to get enough traction to be able to accelerate at an acceptable rate. I am starting the wing design using a symmetric airfoil (NACA 0006). Ideally, I want to be able to create a significant amount of downforce at low speeds, then decrease downforce coefficient at higher speeds. I do not want to create too much downforce at high speeds. This will put unnecessary strain on the car and will increase drag significantly. The goal is to keep enough downforce on the drive wheels to create enough traction to get up to speed quickly. The idea is to have a flap that will start off at a large angle (60 degrees) then decrease angle as the speeds increase. This will lower the lift coefficient (downforce coefficient in my case), but maintain a certain downforce on the drive wheels throughout the speed range of the car.

This is a rough mock up of how the wing will be placed on the car. Because the wing is so close to the ground, ground effect will increase the wings effective downforce coefficient.

Profile view of the NACA 0006 airfoil showing different degrees of flap.

Series of pictures illustrating how the flap will decrease in angle as speed increases:

More wheels and transmitter modifications

2007-11-13T21:17:00.000-06:00

Latest iteration of the "X2"

Wheels

Still working on more custom wheels. I want to try out a number of different wheels to see which ones will work best. I already have two types that I want to try. Each wheel has a different foam thickness.

Wheel being measured for roundness.

Transmitter

I had just about given up on my 3PM transmitter until I found out that increasing the range on my Futaba 3PM 2.4 ghz transmitter isn't very difficult. There are a couple of off the shelf components that I found to increase range. Since 2.4 ghz is widely used in wireless internet, there are many places that sell components such as pig tails and amplifiers. I was able to open up my 3PM and see what kind of connectors were used for the antenna. Then I was able to find a 500mW amplifier to significantly increase my range. This is what the transmitter looks like with the modification:

Futaba 3PM 2.4 Ghz modified to increase range. Range of the stock transmitter is a measly 300ft. With this 500mW amp I have increased the range by about 3x.

Parts used:

Pig-Tail (U.FL to RP-SMA):

500mW Amplifier (RP-SMA):
Gyro:

I included a gryo into my setup. I found out that after I corrected the steering, the car had become much more sensitive with steering input. I tried all the adjustments to minimize this and nothing seemed to work. A number of people have said a gyro helps significantly. This gyro is nice because I can use the third channel on my transmitter to increase or decrease the sensitivity of the gyro without stopping the car to adjust the gyro itself. I can adjust it remotely.

Matt Shumaker described how a gyro affected his car. He has noted that at low speeds the gryo helps significantly by keeping the car on a straight trajectory with much less steering input from the driver. But at high speeds, the gyro makes the car feel numb. This is especially true if the gyro is too slow to compensate for movements in the steering.

Futaba GY401 next to the right rear wheel in the "X2"
Front end displaying the Thunder Power batteries and Castle Creations HV-110 performing perfectly during all of my testing.

I am still working on a wing to create downforce. The tight spaces on my car limit where I can mount a wing. I am now sizing the wing and airfoil section to create the desired amount of downforce at a certain speed.

New wheels and more street testing

2007-10-16T04:46:00.000-05:00

Last time out testing at the Houston Dragway, I had problems with my tires holding together at speeds from 60-70mph. I have been working with my father to make some custom aluminum wheels using 1/8 scale on road tires. The wheels I have been using so far are 1/10 scale nitro drag tires:
These tires are very very soft and they are the correct outside diameter (3.25") and width (1.5") for the X2. Since these tires weren't working, I had to go a different route. The 1/8 scale tires are approximately the correct outside diameter (about 75-80mm) but they are much harder foam. The only problem is they are very wide (3"). What I did was to make my own aluminum rims and remove the foam from a 1/8 scale rim. This way I could use the same method of mounting (1/10th scale clamping hub). This is what I started with:

I removed the foam from the 1/8 scale wheel and glued it onto the aluminum rim. Here's what the new wheel looks like (left) compared to the old one(right). The new wheel is much much stronger and should hold up to the extreme forces.

I also modified the front suspension. I moved the tie rods from up above the upper arms to very low to maintain correct front end geometry:

Data from the last street run. Link to the FDR file from my run on 10-11-07. You can view this after downloading and installing the Eagle tree software.

I have also updated my spreadsheet. I added the ability to choose a motor based on what Kv and Kt requirements are calculated. I also added a section where you can calculate the amount of downforce created by a wing added to the car. And based on the traction created by this wing, you can see at what speed your total traction will intersect with your traction needed to accelerate at your desired rate.

Here is the link to download the spreadsheet for use on your own calculations.

Graph showing traction available vs traction needed. The point where the two lines intersect is the speed at which enough downforce will be created to give you the traction to accelerate without spinning the wheels.

I am still working on the wing and how to attach it to my car. Once the wing is completed and attached, I want to get out to the Houston Dragway as soon as I can to do some more high speed testing.

Road test with modifications for the "X2"

2007-10-07T15:57:00.000-05:00

This is the modified steering. The orientation of the servo is unorthodox. I had trouble making sure that I had enough room for the antenna, receiver and switch after the steering had been rotated 180 degrees. Rather than place the servo laying flat on the chassis behind the steering suspension, I stood up the servo and placed it between the steering mounts to create more room for the electronics all the way in the rear of the car.
This is the front end of the car. This is where the pitot tube ports are located. A pitot tube is used on full size aircraft to measure airspeed. The dynamic pressure port is on the bottom. This port measure the forward airspeed as the car is running. The tube on top is for the static port. This measures the ambient pressure. The difference in the dynamic pressure and static pressure is speed. More info on pitot tubes can be found here.

This is where the air travels down the brass tubes to the silicone tubes to the speed sensor. This is where the dynamic and static pressures are measured.
This is data from a short test run I did on the street in front of my house. There is a lot of noise in the data from 0-8 seconds. The car wasn't even running on the ground between 1-8 seconds. After that, you can see from the spikes in the speed data that I made 4 passes. My fastest pass was about 18 mph.

Currently I am working on getting new wheels put together and making a wing for some front end downforce. I will post more about these parts soon.

Update: Modifications

2007-09-03T17:30:00.001-05:00

I have been working on changing a couple things for the X2. Since I am driving the car backwards, the front steering (now the back) needs to be turned around to keep the correct steering geometry. I turned the steering around 180 degrees. I also got some trailing front axles to keep excessive twitching of the steering to a minimum. I also changed the caster to -4 degrees.

I got an Eagle Tree Micrologger data acquisition system. This plugs in-between the Thunder Power batteries and Castle HV-110 speed control and can accurately measure a multitude of things. Currently it is measuring battery voltage, current, watts, mAh used, motor rpm and will include the airspeed sensor in the future.

I am also working on machining wheels out of aluminum. As you can see from my previous tests, I am having a hard time keeping the foam on the standard plastic rims. I want to experiment with some machined rims and different foam types to see if I can make a wheel that will hold up to the extreme performance of these speeds.

I am also working on a setup to provide downforce on the front wheels. My lack of acceleration is due to the fact that the coefficient of friction is lower than I expected. One way to increase traction without changing foam compound and increasing the weight of the car is to increase the downforce.
Here is a shot of the front suspension. It has been reversed to obtain the correct geometry. I installed trailing axle steering blocks to minimize the steering reaction. I also removed 1 set of washer from underneath the suspension arm mounts to increase the rear ride height to approximately 8mm. The upper arm mount shims were moved to provide -4 degrees of caster.
This is the Eagle Tree data acquisition micrologger. This will help me accuratley monitor voltage, speed, motor rpm and amp draw.
This is a sample graph of what the Micrologger can do. This example was from a quick bench test to see if everything was working. The car was freewheeling on the car stand. There seems to be some noise in the data. The only time the wheels were running is when you can see the rpm move into the 2 "humps" on the bottom of the graph. I was throttling up slowly to neutral then slowing down again. I did this twice. The data right before and after These rpm "humps" shouldnt be there since the motor wasnt even rotating. This could be caused by cogging of the brushless motor. You can see the rpm shoots up to 50,000 then goes to 0, which shouldn't happen.
Wheels being machined

New website

2007-08-18T13:16:00.000-05:00

Updates on my car will continue to be at this website. The new website where I will keep all other fast RC cars will be at www.fastestrc.blogspot.com

I'm updating the site

2007-08-18T08:05:00.001-05:00

I am going to make some big changes with my website. I started this website to keep a detailed record of all the fast RC car projects people are in progress. I also wanted to keep a detailed report of all the high speed events and have all that info in one place. But when I started on my project "X2" and detailing all of my progress, people were getting confused on who was making what car. For example, when Jalopnik reported on my car, they thought it was Nic Case who was making it:

Most full sized vehicles can't hit 200 mph, let alone radio controlled cars (in actual miles per hour, not scale). But Nic Case hopes his X2, currently in development, will do just that. Current holder of RC car speed record of 134.4 mph, Nic's goal is nevertheless an optimistic one. Powered by a 29.6 Volt direct drive motor, the X2's theoretical top speed is 274 mph, but that's without any drag generated by friction with the road or air. Special foam tires capable of withstanding the incredibly high RPMs keep the diminutive car in contact with the track, while a gyroscope manipulates rudders to automatically keep it in a straight line. A video of the X2 running shakedown tests follows the jump.

So after reading this, I am going to change the website to show just my updates for my car. I will move all the other posts to a new website.

The word is getting out

2007-08-03T00:11:00.000-05:00

Caption for the video: For this test I designed a new body out of Lexan. For these tests I was running 8s Li-Po 3300 mah Thunder Power batteries and a NEU 2215/3Y ... all » motor direct drive. I was not getting any range with my Futaba 2.4 ghz 3PM transmitter (only 100ft) so I went back and used my very old Futaba 27 mhz 1024 PCM transmitter. I was able to get almost 900ft of range with my old controller.

The results of my testing showed that around 70-80mph my TMRC drag racing tires would catastrophically fail. They would explode leaving foam all over the track. The car was not damaged in any way.

Well, it looks like the word is spreading about my car and my attempt at 200mph with an rc car. This is great, except for all the wrong information that people have been posting. So far its been at:

Jalopnik

Digg

Autoblog

Engadget

OhGizmo

PistonHeads

Gizmodo

Almost all of the information is wrong in those posts so I will fix it here:

www.fastrc.blogspot.com is the website I started to follow the progress of all the high speed cars in the RC community. After months of reporting on other peoples cars, I decided to create my own high speed car. With my background in Aerospace Engineering I thought it would be a cool project.

The info in the post isn't correct, My name is Nick Maslowski and www.fastrc.blogspot.com is mine and the X2 is the car I designed and am testing now. Nic Case is the current record holder at 134.4 mph for an RC car. I just report on the high speed events and peoples cars, that is why he is on my website. His electrified nitro Associated TC3 went 134.4 mph at last years World Fastest RC car contest. This year he got 127.2 mph with an electrified Shumacher Fusion.

I use the website to post updates on my progress and post updates on other high speed contests. I started with the design phase on a CAD program called CATIA V5 (Boeing uses this program to design their planes, I work for Boeing as an aerospace engineer). I spent 6 months designing it, then 2 months ago I built it, and now I am testing the X2. My ultimate goal is to reach 200 mph by next years Worlds Fastest RC car contest held by RC Car Action magazine. What you see in that video is the first real ground test of the car. I had not gone above 30 mph before this video was shot. In that video I was able to get it up to around 80 mph. Then I had issues with the foam tires exploding due to the VHT on the surface and the coefficient of friction being very inconsistent. The car is still in the prototype stage. (you never see a new corvette being tested with a showroom floor finish, right? It always has a camo mask on and a lot of temporary aero pieces.) The whole car isn't finalized and is still subject to a lot of change before its final form. The guy taking the video is an older gentlemen and his health isn't the best. He is an expert in chassis design and suspension systems. He has helped me out a lot. The Houston raceway is the only place to open up a car like this. Its flat and I have plenty of room to wind it up and slow down.

I am working up to the cars full power from test to test. The average person doesn't know much about real RC cars and here is the info on this one: The finished power set-up will use a 12s (44v) Lithium Polymer battery from Thunder Power. The motor is a Neu brushless custom modified 2215/3y. It has a power capacity of 5000 watts (around 6.7 hp) and will be spinning the wheels at 21,000 rpms at 200 mph. The speed control is a Castle Creations HV-110 airplane controller. It can handle up to 44 volts and 110 amps continuous. No other RC car has this much power in such a small package.

If anyone else can build something faster, I'd love to see them try. Email me on my website at www.fastrc.blogspot.com about your try at these high speeds.

-Nick M.

Video "X2" Update: Testing at Houston Raceway drag strip

2007-07-24T17:51:00.000-05:00

Here is some video of when we first arrived at the drag strip. I start by slowly increasing my speeds on each pass. On the last pass you can hear buzzing as the car goes by. The buzzing sound is caused by the wheels becoming unbalanced as they lose more and more foam. In the pictures below you can see tire chunking. Top speed in this video was about 70 mph. Another thing to point out is how quiet the car is. Since this car has no gears or transmission, the only thing you really hear is the motor whine as the brakes are applied or if the chassis scrapes the ground. On faster runs all you can hear is the disturbed air as the car blows by. Around 3:10 is the fastest pass.

"X2" ready to get started.

I made a new Lexan body to conform with the car driving backwards. On my previous test runs I found out that driving with the motor in front and drive wheels in front greatly improved stability. On the left is my old Futaba 1024 27 mhz PCM transmitter that yielded about 4x better range than my brand new Futaba 2.4 ghz 3PM.

One set of tires blown up.
Another set of tires blown up.

Tire carnage from a day of high speed testing. I went through 4 sets of tires today. All had the same problem of self destructing. The adhesive between the rim and tire could not hold everything together.

My max speed out of these tests was about 70-80mph. We were also using a radar gun to measure speed and it closely matched my on-board speed meter.

I was able to get permission to test at the Houston Raceway. Its a full scale 1/4 mile drag strip on the east side of Houston in Baytown Texas. For this test I designed a new body out of Lexan. I was running 8s Li-Po 3300 mah Thunder Power batteries and a NEU 2215/3Y motor direct drive. I was not getting any range with my Futaba 2.4 ghz 3PM transmitter (only 100ft) so I went back and used my very old Futaba 27 mhz 1024 PCM transmitter. I was able to get almost 900ft of range with this old controller.

The results of my testing showed that around 70-80mph my TMRC drag racing tires would catastrophically fail. I would hear a very loud "crack" or "pop" as they would explode leaving foam all over the track. The car was not damaged in any way and was still very controllable even after tire failure.

After testing, I checked TMRC's website and it says that these tires have gone 107mph on nitro drag cars. I called and they said that other racers have encountered the same problem I have. They basically said that the tires might be hopping off the ground and free-wheeling for a split second. This causes the RPM's to go way up and the tires can fly apart. I will have to go back and try different spring and dampening combinations to minimize my wheel hop.

Testing today - great success!

2007-07-15T17:10:00.000-05:00

Equipment all setup at the testing site

John Stranahan sweeping off the test area.

Its ugly but functional. The body and aerodynamic pieces are prototypes.

Today was a great testing day. I made awesome progress. Before today, I was having a ton a problems keeping the car pointed straight ahead. I could drive the car up to about 40 mph, then if I gave the car any kind of steering input, the car would fishtail and spin out. To fix the problem I tried changing camber/caster, spring weights, shock oil weights...anything. I was totally stuck then I got an idea. Run the car backwards. Run the car with the motor/drive wheels in the front and the steering in the back. I tried it and it worked great! Today I was able to get up to 60 mph (about 1/4 throttle) with no stability problems. I actually had too much straight line stability because I couldn't steer the car above 40mph. This issue has more to do with the sizing of the vertical stabilizers. I can use smaller ones for my next tests.

Acceleration was phenomenal and during braking the car would stay in a straight line without any effort. Today marks a huge milestone for my project "X2". I couldn't go any faster today because of the size of the area that we have to work with. Its only about 100 yards to work with. To get my car up to its full potential I need to find a much larger, flatter surface to test. Hopefully next weekend I'll be able to test at a much larger area.

The only problem for today is not being able to capture video of my car in action. We had technical difficulties with my camera and I wasn't able capture video with my car. But I did get a catch a close call with John's car. He was making a high speed pass and his car almost hit my full size car:

WFRCCC 2007 Rules

2007-07-14T21:05:00.000-05:00

WFRCCC entry form

WFRCCC 2007 Rules

WFRCCC RULES
1. Wheel-driven vehicles only. Vehicles powered by thrust (jet, rocket, propeller, etc.) are not allowed. Turbine power is allowed only if the turbine is used to drive the wheels, not for thrust.

2. Vehicles may be powered by engine(s) or motor(s) of any number and configuration.

3. Vehicles may be any weight, with any chassis configuration and any number of wheels—but the completed vehicle may not exceed 40 inches (1016mm) in length.

4. All vehicles must use commercially available radio gear with a functioning fail-safe system set to apply full brake in the event of signal loss or interference.

5. Vehicles are not required to look like any type of "real" car or truck, but all entries must have some type of 3-dimensional "cockpit area" with windows (clear or painted). It's OK if your car looks like a space ship as long as it appears to have a place for a guy to sit.

6. No sacrificial power systems. Motors or power systems that, by design, are inoperable after a single run are not permitted.

7. Drivers must operate their vehicles from a fixed position. Chase cars are not permitted.

8. Drivers or teams may enter as many cars as they like.

9. For a speed record to count, the vehicle must make a second run and achieve a speed that is within 2% of the record speed. The second run can be made at any point during the event, the runs do not have to be back-to-back.

ENTRANTS
Entrants will be divided into three classes: Manufacturer Team, Independent Team and Individual.

MANUFACTURER TEAM: entries fielded by RC companies will run in the Manufacturer Team class.

INDEPENDANT TEAM: if the entered vehicle is the collaboration of three or more individuals operating without the support of a manufacturer, it will run in the Independent Team class. High school shop teams, university engineering departments, RC clubs ... this is your class!

INDIVIDUAL: any vehicle entered by a single person will run in the Individual class.

THE WINNER
Each vehicle will be given three attempts to make its fastest run. The vehicle with the absolute highest peak speed will be declared the overall winner, and separate awards will be given to the fastest vehicles in the Manufacturer, Independent and Individual classes.

Some questions I've received:

What is the length of the track? It's a full-scale 1/4 mile drag strip. Use as much of the track as you like.

What’s the run up and slow down length See above. You'll have the same shut-down area as a full-size drag car.

Do we need to do 2 runs in either direction? Covered in rules posted above.

Are they one after the other or do you get a period to prepare the car for the 2nd run? Once you're up, you can make more than one run if you want, but once you take the car off the track, it will be the next driver's turn

What happens if you can’t make the 2nd run? Skip your turn, then go in the next opening. If the event runs like it did last year, we'll be following a simple "go when you're ready" system. If you're not ready to go, the next person who IS ready will go. If you're ready after him, you can take the track. It's pretty laid back, we want everyone to get all the track time they can and have a good time.

What constitutes a manufactures team? See post above.

What frequencies can we use for radio equipment? (We don’t have the same ones in Europe and don’t want to get there and have to buy new equipment) Anything you bring should be fine. All radios will be off except for the driver's on the track. I'll bring a spare radio and receiver just in case any driver has an issue.

Are we allowed to modify radio equipment? The rules state "All vehicles must use commercially available radio gear with a functioning fail-safe system set to apply full brake in the event of signal loss or interference." Personal comfort mods (aftermarket wheel or grip, that sort of thing) are ok, but electronic mods are not allowed. I changed my mind, after seeing a few of the radio-mod posts. As long as your "base" radio is an available hobby item, then it's all good.

Are we allowed to boost the output of the transmitter (2.4 ghz is no licensed up to 100 mw but you can get a license for more and boost the signal to 5 watts and get 5 miles range. Can I use this equipment in the USA?) Sorry, need to use out-of-the-box gear.

Can you use other digital frequencies? 900 mhz, 1.2 ghz, 1.4 ghz….. up to 5.8 ghz. These are not available commercially but people are looking at these systems (Me!)
I'll allow this as long as there's no performance advantage.

Speed control out for repair

2007-07-11T11:49:00.000-05:00

Here is the "X2" currently without the speedo

Becky and I just married

I haven't been working on my car for the past 2 weeks. There are a couple reasons for that. One, I got married on July 6th and two, my HV-110 doesn't want to arm my motor. Even if my car was working, these past 2 weeks have been so busy I wouldn't have had much time to do testing anyways. The HV-110 is in the hands of Castle Creations now and hopefully I can receive a new HV-110 soon since it is still under warranty.

Video: Ground test #2

2007-06-23T16:11:00.000-05:00

Here are some more test runs of my project "X2" speed run car. You can see that I am still having stability issues and oversteer problems. At the end of this video I almost run into John who was filming the run.
This is a test prototype of the body and wing. The body is made from fiberglass. The body attaches to the chassis with button head screws on the sides. The wing is a NACA 9509 airfoil section. I made this wing in college for wind tunnel testing.

The weather held out for John and I to do some testing. There are a couple changes I made since the first ground test. I made a longer chassis out of carbon fiber instead of G10. The G10 chassis was my prototype chassis. I used it to place my components and see if the layout was correct. I found that the car has too much over steer. I have been trying to remedy this problem with much stiffer springs in front. This did help a bit, but I found that carbon fiber has a much better resistance to a torsional load than G10. This means that the chassis bends less and the suspension can do its job more effectively.

The tests didn't prove as promising as I would have liked. I still cannot get my speed up above 30 mph. The steering is way too sensitive and it makes the car spin out. It feels like significant over steer. You can see this in the video. Right at the end my car wanders towards John and I almost hit him.

My new Futaba 3PM 2.4GHZ radio does not have nearly as much range as my very old Futaba 3PK PCM system. The 3PM gave me only about 400' of range. Very disappointing. I was hoping for much more.

After my disappointing testing on Saturday, I also didn't have a very good day today (Sunday). I was testing different front camber/caster settings to help remedy the over steer problem. I go and test a camber change, stop the car, make another camber adjustment, then I go to turn the car on and now my speed control wont arm my motor. I am not sure what the problem is at all. I tried to recalibrate the radio, I tried my old radio and I still cant get it to arm the motor. So at this point I am out of commission until I fix the speed control.

Design Update

2007-06-23T04:24:00.000-05:00

Here is the new stretched carbon fiber chassis next to the old G10 chassis. The new one is 50mm longer in the wheelbase.

During my first couple of test runs, I had a lot of difficulty getting the car to track straight. It was tough to get on the throttle and get the car up to speed without the car getting very squirrelly. I decided to lengthen the chassis and make it out of carbon fiber instead of G10. The carbon fiber has much stiffer properties than the G10 and it seems like the chassis doesn't want to warp as it did with the G10. This lets the suspension do its job

Testing rained out this past weekend.

2007-06-19T21:13:00.000-05:00

This is what it looked like 5 min before it started to pour
Here is John's car doing some high speed runs to check out the running surface.

This past weekend was pretty much rained out. John and I did get to go out to the testing area (Best Buy parking lot). We got a couple runs in but after 5 min it started to pour. This weekend looks promising. Much better for testing.

I got my new Futaba 3PM 2.4ghz transmitter installed. I plugged everything in but now I am having problems with the throttle again. It doesn't sense neutral. I have to hold the brake to keep the car from rolling. I am trying to set it up so it doesn't do this. I also installed much stiffer side springs on the suspension. I was using the silver 8lb/in springs before, now I am using the copper 16lb/in springs. This drastically improved the way the car handles. With the added weight of the extra battery, the car would want to keep swaying back and forth and never go in a straight line. With the stiffer springs, this has almost disappeared.

Update: I was able to adjust the throttle trims and subtrims to get my new Futaba 3PM to work with my awesome Castle Creations HV-110.

Video: First low speed test run of "X2"

2007-06-09T12:38:00.000-05:00

This is the first low speed ground test of my project "X2" Insane Speed Run car. This test was to mainly check for radio range, ESC setup and testing area. I didn't even have the body on for these tests. In this video I wasn't driving the car, John Stranahan was driving so I could record the video of the car in action(You can see him doing some donuts in the early part of the video). This was the fastest he or I let the car go. We didn't want to go too fast for our initial tests. He helped me a great deal this morning with the final preparations to get the car running. A couple things to note; The car is completely silent. Since there are no gears the only sound the car makes is when it scraped some rocks on the ground or the chassis scrapes from bottoming out. The biggest problem is setting up the HV-110 for the car. Now there is nothing wrong with the controller. The Castle Creations HV-110 works perfectly, its just that its been designed for planes and not for cars. Its difficult, but Nic Case has been helping me set-up this controller. The problem is that I have to hold the brakes or the car will take off. Basically, full brakes is neutral and anything less than full brakes is throttle. Nic Case has offered a solution:

Nick
I just read your post.
If you need a little help tuning your radio with the 110----- here is what I know............

(the HV is for planes, so it naturally wants to go from 0% to 100%-- like a stick. But a pistol radio goes from -100% to neutral to + 100%------------) you will not be able to actually get it to "coast" , it will go from 1% forward to brake--- no neutral.
The trick is to try to the trigger to fell like a "car"

First, in your Castle Link, set it up like the attached.

On the radio it self, turn the throttle end points down to 75%.
From here turn you car on (4s- no tires) and play with the sub trim to try to find neutral.

If you can not adjust the radio to find neutral at your trigger---- you may have to hook a rubber band round the trigger to pull it to full brake.

Hope this helps
Good luck
Nic

With these 8s Thunder Power cells and this HUGE Neu 2215 motor, the car will break the tires loose at just 1% throttle. In this video, John and I never got more than 5% throttle out of this car in fear of spinning out due to the massive power.
The black tire marks are from the traction compound that we applied to the tires earlier. You can see it coming off the tire and absorbing into the asphalt surface.
This is the testing area. Its a newly paved parking lot. This area in the picture is about 100 yards. You can see John in the distance testing radio range of our transmitters.

The first low speed ground test of my project "X2" went really well. Master Mechanic John Stranahan helped me out this morning. We didn't test for high speed but we tested the electronics, the range and checked out the testing area.

I think this first test was a success. The car was moving great and I didn't break anything! The next order of business is to fix the throttle issue. Also, I have to complete the rear fairing and vertical stabilizers. The next test will include the aero package and higher speeds. Hopefully next weekend the weather will be just as good as today.

Ready for road testing

2007-06-09T00:39:00.000-05:00

Well, its about 12:45 am CST Saturday morning. I am going to go testing this morning at around 8am. The electronics are all together and at this point the body still needs a little trim work so I didn't include it in the pic. I intend to run Thunder Power 3300s in 8s and do some low speed testing to get the transmitter dialed in and the speed control calibrated. Keep in mind that this Castle Creations HV-110 is designed for use in planes. So setting up this thing in a car is a task. I hope to get some pictures and video of the testing and I will post the results here. My friend John Stranahan will help me out with some chassis tweaking, electronics set-up and timing. We will use a quick and dirty way of measuring speed. We will measure out a set distance and time how long it takes to go that distance. Hopefully everything goes well. Wish me luck!

First test

2007-05-31T21:28:00.000-05:00

The first bench test ended up like this. I got the clamps modified, installed the motor/ESC/Batteries and I fired it up. I wanted to see how much tire growth and how the tires would hold up from just 8s power (around 30v) which gives me a max of about 15k rpms. As you can see the tired failed. There was also a large amount of tire growth. I ordered some new tires and they should be in next week. Hopefully doing actual testing on the ground (no free-wheeling) will keep the tires from failing.

Motor is here!

2007-05-30T06:10:00.001-05:00

Here is the motor. You can see how big this thing is. I am holding a regular 540 motor up next to this monster.

I am going to have to make modifications to this clamp(the opposite clamp installed perfectly). You can see that there are some red tie-wraps that hold the motor wire to the inside of the can. I did not account for these wires when I was designing the motor clamps. The way it is now, I cannot tighten the one clamp because of these tie wraps. It shouldn't be a problem because I can cut some recesses in the clamp to make room for these tie-wraps.

Construction update

2007-05-20T20:55:00.000-05:00

Here is the work done so far. The chassis is made from G10 material. This is a prototype chassis that I can work on to get all the bugs worked out. The final chassis will be made from carbon fiber. I am still waiting for the Neu 2215 so that space in the motor clamps is open. I have made a couple design changes since my last update and have decided to go with a 12s setup instead of the original 8s. The extra 4s pack is represented by the blue ni-cad pack laying across the chassis. This is where I will place the extra 4s li-po pack when I receive it. The Castle Creations HV-110 speed control is under the blue pack. This speed control was generously donated to me from Joe Ford at Castle Creations. The extra 4s li-po pack is represented as this blue ni-cad pack. The two Thunder Power 4s 3300 packs are the black ones side by side. This picture shows my donor RC10L3 located above my project "X2". This is the car where I got all my suspension pieces.
This is the latest CAD model. I have made a couple changes since my last update. I am running an extra 4s pack across the chassis (12s total).
Top view detailing the Castle Creations speed control and Thunder Power batteries. (Blue pack will not be used for the speed run)
This is a detail shot of the great work that Darren at Aggressive Technologies has done for me. He CNC'd these motor clamps for me. They turned out great. Thanks Darren.
CAD model of the motor clamps.

I have some electronics still waiting to show up. The Neu motor is on the way and should be here by next week. Then I will start bench testing. I'll post my results here.

Video: pressure distribution at 200mph

2007-05-13T19:13:00.000-05:00

Stress plot of applied pressure due to 200mph speeds. (deformation exaggerated 91,000 times)
Applied forces used in the analysis.

This is an animation of the forces acting on the body shell at 200mph. The movement of the body is greatly exaggerated to help show how the body deforms at these high speeds. The video runs through quickly, so you might have to pause it at different steps in the video to see all the details. One thing to note is how much stress is concentrated on the front wheel wells.

Construction Update: Making the body

2007-04-22T17:44:00.000-05:00

I started by glueing together foam blocks. Then I printed out the profile of the body and cut it out. I glued that on to the side of the foam to use as my template.
I sanded the foam down to the desired template profile.
I laid the fiberglass resin material on top of the foam. I let that stand for about 24 hours until dry.
This is how it looks after I remove the foam from the inside of the body. I don't like it. It contains a lot of air pockets, bulges and rough spots. For my first time working with fiberglass, it isn't too bad, but not as good as I would like it.
Here you can see my first attempt at making the body. In the background is my 2nd attempt. The 2nd attempt already looks more promising than the first.

Locating the CG

2007-04-06T09:41:00.000-05:00

Location of the CG relative to the axles and the ground plane.

Locating the Center of Gravity is important to help figure out the handling characteristics of the car. CATIA has a very simple way of calculating the CG of an assembly. After all the individual component densities are applied, an overall mass and location of CG can be found. Currently the mass of the car is 2.36 Kg (5.2 lbs).

Update: Sending out designs

2007-03-28T12:52:00.000-06:00

It has been a couple weeks, so here is an update:

The drawings for the chassis components have been sent to be made. Matt Shumaker has a CNC machine that he will use to make a hole template. I can use this template to guide the critical locations of the holes in the chassis. I will be able to use this template to make future chassis. He is also going to donate some 3mm carbon fiber. Thanks Matt!

The drawings for the machined aluminum parts (hubs and motor clamps) have been sent to Darren at Aggressive Technologies. The hubs must be extremely balanced to survive the 22,000 rpms they will encounter during the 200mph run.

I have the batteries, chargers and balancer thanks to Thunder Power!

I have contacted Steve Neu at Neu Motors about making a custom 2215 1.5Y for my car. It looks promising as they have said the design is possible.

I have been in contact with Joe Ford at Castle Creations about an HV-110 speed control. They have been very excited and helpful with getting a speed control.

So far so good. The CAD design is finalized and getting all the parts manufactured and put together is the next step. Check back again to see more updates.

Design Update

2007-03-09T11:21:00.000-06:00

I have updated the design. I am currently waiting for software so I can run a CFD analysis. I am going to use Fluent for CATIA. Fluent for CATIA isn't as accurate as some standalone programs, but it makes it much easier to mesh and post process natively inside of CATIA instead of doing many steps of translating the files.

Design update

2007-03-01T11:30:00.000-06:00

Picture of the aerodynamic components in place. I removed the tail booms and attached the vertical stabilizers to the rear fairing.Picture of the flat bottom. Some of the hardware is missing and some hardware is in place. I mainly wanted to size up the nuts and bolts needed for the custom designed parts.

These are some updated pictures of the car with the body and rear fairing attached.

Thunder Power is here!

2007-02-28T18:21:00.000-06:00

I just received the batteries and charger from Bob Burns at Thunder Power. He also sent me 2 T-shirts and a bunch of stickers. Thanks Bob! I am going to post some updates to my car in the next couple days.

Make a donation

2007-02-27T10:31:00.000-06:00

If you would like to be part of this project, go ahead and click on the button to the right. You can use an existing Paypal account, setup a new one or pay with a credit card. You can enter an amount you like. I will keep track of everyone who donates and place their names on my car.

Design update

2007-02-21T12:25:00.000-06:00

I have updated my model to reflect some changes in the design. The car is now based on a NEU 2215 1.5Y motor. I wasn't getting any luck from Lehner and this motor also costs a bit less for about the same amount of power I was looking at before. I also narrowed the chassis down from 200mm to 180mm. I relocated the receiver to the front of the car to get it away from the electronics to help with interference. I removed the gyro and rudder servo.

We have Thunder Power!

2007-02-16T20:12:00.000-06:00

Thunder Power has generously donated some of their batteries and will be the sole provider of power for my car.

Sponsors so far:

Batteries: Bob Burns at Thunder Power will supply the TP3300-4SX 14.8V 3300mAh 4-Cell packs, a charge and a balancer. These are the best Li-Pos around. Thanks Bob.

CNC machining: Aggressive Technologies has lent his CNC machining skills. Darren at Aggressive Technologies also mentioned that he knows pro driver Paul LeMieux. Paul Lemieux is one of the best touring car drivers in the world and has an impressive list of wins in the last few years. Hey Paul, do you want to drive this thing for me? Everyone knows that I can't drive. Plus, if you do wreck the car, I won't be responsible!

Carbon Fiber: I have been in contact with Matt at Ballistic Technology. He has done some excellent work on RC cars as well as top quality RC helicopters. He might have some extra carbon fiber to loan me. I have also contacted Wes at Out Front Frames. He has services available to make the chassis components.

Sponsors still needed:

Motor: Lehner can become a sponsor or someone can donate a Lehner 3060/7 motor for this car.

Speed Control: I have emailed Castle Creations asking if they would like to sponsor me. I am looking for a Castle Creations HV-110. If anyone has one available or would like to donate one, please contact me: nick.maslowski@gmail.com

200 mph prototype- Looking for sponsors to help build

2007-02-12T12:56:00.000-06:00

Design Update-3/9/07

Design Update-3/1/07

Design Update-2/21/07

This is a project I have been working on for a couple months. I have been designing this on CATIA V5. It is electric and based on a RC10L3. My design uses a 3mm thick piece of carbon fiber for the main chassis and for the various rear suspension pieces. The motor is a Lehner 3060/7 which has a 1000 rpm/v rating. It uses 8s1p Li-Po for a total of 29.6 volts. This equates to a theoretical maximum rpm of 29,600 rpm with no load. The rear wheels are 79mm in diameter. At theoretical max rpm with no transmission or gear reduction (it is direct drive), the linear velocity is 273.87 mph. It will never reach that speed due to the high aerodynamic drag it will encounter. Wind tunnel testing needs to be done to calculate its drag coefficient. The car will also use a gyro for lateral stability. It will be used in a similar way as a gyro is used in helicopters and planes. If there is a gust of wind that forces the car to move in one direction, the gyro will sense this and compensate by sending a signal to the rudder servo. The rudder will move in a direction to counter the effect of the wind gust. It will help keep the model pointed in a straight line by dampening the effects of a cross wind. This is known as a heading hold mode on gyros.
This view shows the components with the body removed. The tail booms and vertical stabalizers have been left in place.
More views of the X2 prototype
CATIA Model

This is still a work in progress as 90% of the design work is done. As you can see from my model, I don't have many of the smaller connecting hardware modelled. I also didn't fully model the parts that I knew would be using off the shelf. The idea of this initial model was to size up the components and to see if the design would be possible. All of the components needed to build this are modelled and fully detailed with dimensions. I have all the blueprints to build this (the drawing of the chassis is shown below as an example). After completing most of the modelling I can see that this will be possible except for one thing: cost.
Example of the chassis drawing with full dimensioning.
Quick power required estimates (courtesy of Gordon Freeman)

The problem is the cost of making some of these parts. The chassis parts aren't too expensive to produce. The expensive parts to be machined are the hubs used to attach the motor to the wheels. I also need the motor clamps to be machined. Initial pricing quotes for the CNC machining on the hubs is around $400... each! The motor costs around $700. All the suspension components can be taken from an RC10L3/4. I would like to make this car happen but I need help. If anyone could donate materials or skills in making this car, that would be awesome. If you know how to machine or can donate some pieces of 3mm carbon fiber, you'll be able to see your components be put together on this record setting car. Everyone who has helped make this happen can have a spot on the body of the vehicle for some much appreciated thanks and ad space (just like NASCAR)! If you would like to donate skills, email me at nick.maslowski@gmail.com. I can send you the specs and drawings for the components that you have the skills to make. Then I'll take your finished product and put it on the car. I will keep a detailed step by step construction process as I get the parts and post it here on this website. I wish I didn't have to beg from others, but I don't have the funds and would love to see something like this car built and run. I would like to have it complete in time for RC Car Action's Worlds Fastest RC Car contest on July 28, 2007.

Updated 2/16/07

Sponsors so far:

Batteries: Bob Burns at Thunder Power will supply the TP3300-4SX 14.8V 3300mAh 4-Cell packs, a charge and a balancer. These are the best Li-Pos around. Thanks Bob.

CNC machining: Aggressive Technologies has lent his CNC machining skills. Darren at Aggressive Technologies also mentioned that he knows pro driver Paul LeMieux. Paul Lemieux is one of the best touring car drivers in the world and has an impressive list of wins in the last few years. Hey Paul, do you want to drive this thing for me? Everyone knows that I can't drive. Plus, if you do wreck the car, I won't be responsible!

Carbon Fiber: I have been in contact with Matt at Ballistic Technology. He has done some excellent work on RC cars as well as top quality RC helicopters. He might have some extra carbon fiber to loan me. I have also contacted Wes at Out Front Frames. He has services available to make the chassis components.

Sponsors still needed:

Motor: Lehner can become a sponsor or someone can donate a Lehner 3060/7 motor for this car.

Speed Control: I have emailed Castle Creations asking if they would like to sponsor me. I am looking for a Castle Creations HV-110. If anyone has one available or would like to donate one, please contact me: nick.maslowski@gmail.com

Video: wind tunnel testing

2007-02-06T23:43:00.000-06:00

In college, I wanted to do something interesting for my senior project. I decided I wanted to look at different types of air foil shapes to replace the standard wings that have been used in oval racing. My goal was to find a design that was much more efficient at producing downforce. I tested 4 different wing configurations at 3 different speeds from 0 to 112 ft/s (77 mph). Here is a link to my full report (PDF).

This is a video of the car being tested from 0 to 80 mph. There is an airspeed indicator in the upper right of the screen. As it reaches 80 mph you can see how much the wing bends down from the force of the air. It also starts to flutter at those high speeds (its hard to see, but its starts shaking at about 60 mph)
Car ready to be tested in tunnel
This shows the setup used to measure the loads. There is one load cell for the front end of the car and one load cell for the rear of the car. There is a force trasducer to also measure drag. The load cells and force transducers work by measuring resistance in a strain gauge located in the load cells and force transducers. A voltage is applied to the strain gauge and current and resistance is measured. As a load is applied the length of the conductor changes and its resistance changes. The changes in resistance are measured and then the actual load applied can be calculated. I could only measure half the downforce applied to the rear end because I only had one force transducer. The graphs shown below only represent half the total downforce on the rear axle. It was unfortunate to have many problems with getting accurate data from the front force transducer. I was unable to get any data loads from the front axle of the car. I would have liked to compare the front to rear downforce.
Traditional wing and spoiler installed
Anderson airfoil
Anderson airfoil cross section
NACA 9509 airfoil
NACA 9509 airfoil cross section
This is the shape of the wing with zero windspeed.
Severe wing deformation at 80 mph
Drag vs. Speed.
Downforce vs. Speed. You can see that the baseline body (no spoiler or wing) actually creates lift. This can be terribly bad at high speeds. Even using a spoiler reduces lift significantly. Also, you can see the standard wings downforce falls off dramatically above 50 mph. This is because of the deformation that is caused from the high speed. The lexan material is not able to keep the wings shape and causes it to lose its effectiveness.

This is a link to the facilties I used at Iowa State. I used the Bill James Wind Tunnel. Its an open circuit tunnel for aerodynamic testing (3.0 ft wide by 2.5 ft high section) with 180 mph wind speed capability.

Worlds Fastest RC car challenge Saturday July 28, 2007

2007-02-06T17:01:00.000-06:00

WFRCCC II: Saturday, July 28, 2007

From Pete V. of RC Car Action:

Same rules as last year, but we'll also be posting new rules soon as to what constitutes a Mini, a Monster Truck, a Motorcycle etc. Again, ANYTHING that follows the essential rules (wheel-driven, 40" long or less) will be allowed to run. But if you stretch an RC18T to a 12" wheelbase and run 1/10 scale touring car tires in it, you can't say it's running in the "mini" class.

We also want to avoid endless sub-classes (for example, we won't have Monster Truck nitro, Monster Truck brushed, Monster Truck brushless, Monster Truck 1/8, Monster Truck 1/10--there will just be "Monster Truck")

"Worlds Fastest" rules

THE VEHICLES
1. Wheel-driven vehicles only. Vehicles powered by thrust (jet, rocket, propeller, etc.) are not allowed. Turbine power is allowed only if the turbine is used to drive the wheels, not for thrust.

2. Vehicles may be powered by engine(s) or motor(s) of any number and configuration.

3. Vehicles may be any weight, with any chassis configuration and any number of wheels—but the completed vehicle may not exceed 40 inches (1016mm) in length.

4. All vehicles must use commercially available FM radio gear with a functioning fail-safe system set to apply full brake in the event of signal loss or interference.

5. Vehicles are not required to look like any type of "real" car or truck, but all entries must have some type of 3-dimensional "cockpit area" with windows (clear or painted). It's OK if your car looks like a space ship as long as it appears to have a place for a guy to sit.

6. The vehicle must remain operable after its speed runs. Sacrificial motors or power systems that are inoperable after a run are not permitted.

7. Drivers must operate their vehicles from a fixed position. Chase cars are not permitted.

8. Drivers or teams may enter as many cars as they like.

THE ENTRANTS
Entrants will be divided into three classes: Manufacturer Team, Independent Team and Individual.

MANUFACTURER TEAM: entries fielded by RC companies will run in the Manufacturer Team class.

INDEPENDANT TEAM: if the entered vehicle is the collaboration of three or more individuals operating without the support of a manufacturer, it will run in the Independent Team class. High school shop teams, university engineering departments, RC clubs ... this is your class!

INDIVIDUAL: any vehicle entered by a single person will run in the Individual class.

THE WINNER
Each vehicle will be given three attempts to make its fastest run. The vehicle with the absolute highest peak speed will be declared the overall winner, and separate awards will be given to the fastest vehicles in the Manufacturer, Independent and Individual classes.

Special awards will also be given for "Most Innovative Design," "Fastest-Looking", "Fastest Production Car" (for vehicles that are still recognizable as production-based cars and trucks), "Fastest Engine-Powered Car" and "Fastest Electric Car." We may also make up some awards at the event, based on the type of vehicle that show up (Fastest Monster Truck? Fastest Motorcycle? Surprise us!). It's a top-speed contest, but we'll also reward creativity and originality; we don't want every car to be a rail with 20 cells.