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.