Pictures of the X2 progress in chronological order

Monday, September 3, 2007

Update: Modifications

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

5 comments:

Terry said...

I am continuing to follow your progress with abatement. I am curious if you have a tentative timetable set... even a loose personal goal for a completion date... not that you have to post it here. :-) It's funny... I have zero investment in this project, none of the means or knowledge to approach such a task, but I want to see it succeed in a way as if I had an involvement. I think I need to occupy myself better. That said, you obviously have my best hopes for your success.

-T-

Nick Maslowski said...

Thanks for the compliment. I am glad that you find my work interesting.

As of now I do not have a firm timetable. Initially I wanted to go as fast as I could by next years Worlds Fastest RC Car contest. But some opportunities have come up that might enable me to reach some serious speeds before the contest next year. I will post about these opportunities in the future.

Thanks again for following my blog.

Jake said...

I'm coming for you NASA mines quicker you'll see. But the tech you are using is awesome we are building two completely different cars to do the same thing. There is know doubt you are a very well educated guy using tech I would not even know where to start. But its all about you being able to drive a car that fast. Can you drive it or will it drive you? Nic case did not even get close to 160mph this year. The graph's are awesome if your a collage professor teaching a class. I built my car using common sense and what I learned about physics in high school. I'm just giving you a hard time it's just cool to see such opposite types of cars being built. I really think I will beat you to the punch if the weather holds this year. One of the guy's that helped me will not even talk to me now because I have taken so long. When I do it I will give them full props because they had faith before I had the car built. Look forward to meeting you on the battle field!!!!!Good Luck NASA your going to need it!!!!!!!!!! shoot your e-mail to me Ill send some photo's to you

Nick Maslowski said...

Jake, I am learning how to drive the car every time I go out for testing. Yes, it isn't easy, but the more testing I do, the more I will be able to control the car.

Its good to see some tough competition. This is what the contest is all about! I will see you next year!

What is your email address? My email is in my profile for this site.

chris said...

hi nick you might want to know you have more compotition but im not giving away any info its all being kept secret till i know it works lol hope it all goes well, i want someone to meet at the finish lol