X3.5 Ready to go...

New car ready to take out and stretch its legs.

X2 update-new batteries

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

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

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

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

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

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

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

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.

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

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

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