Franken-body, ugly but functional

[Mod Man]

Hey Guys,

I have found that I need more downforce than I had with my CF body. So, while I make changes to the CF body, I decided to make a simple, high downforce body for experimentation purposes, and this is what I came up with.

Now, bear in mind, the purpose of this project was to make the simplest body I could. So, I picked up some .060" lexan and went to the shop. 90 minutes later I had this body finished.

So, it is definately ugly with a sort of "Mad-Max" appeal. It reminds me of a late seventies 1/8 scale car. ;)

Anyway, I have run the car at 75mph with this body (6S rather than the 12S it is setup for) for testing.

The car runs very well with this monstrosity, ugly though it is. It even corners very well with the downforce I am getting. The car has a bit of oversteer up to about 40mph. Beyond that, it weather vanes into the wind due to the large side dams acting as rudders. I let the car run for a good 3 to 4 seconds wound out at 75mph and it was well planted and relatively easy to control.

Anyway, I will be running the car tomorrow on 12S if the rain stays away. Tonight and tomorrow morning I am rebuilding the car. I stripped the pinion and spur doing some drag car launches as a test. After all, I have put 42 miles on the car since the CF body was made. :D

Matt

[Smib]

That doesn't look too bad, although I imagine that it will suffer from massive doformation, even deadation, at 100mph+ speeds. Also, didn't the rules say something about having to have something that resembles a cockpit? Anyway, it's cool to see you continually experimenting, I might have my money on you for the next comp.

[fasterthanspeed]

Hes not going to the speed challenge.

It looks better than mine. which is nothing.

[Mod Man]

Yes, I am supposed to have a canopy area of some sort. But, this is for testing. :)

The body is .060" thick Polycarbonate (Lexan). It is also braced the the front and back. It should not deform. But, I haven't run it than fast yet. It is strong, but heavy. I haven't weighed it yet. But, I would guess it is about 15 ounces or so.

Anyway, yes, I do alot of testing. However, bear in mind, most things I try slow the car down. So, I reverse what slowed it down and try something else. Hmm, that gave me an extra 2mph. Lets try this. Well, that I just lost 4mph. Let's go back to the original setup and change something different.

If I do that enough, I eventually hit on things that give me more speed. ALso, I run without any traction compound. If I ran VHT, downforce would not be nearly so critical. But, I am determined to make speed without it if at all possible.

Matt

[Mod Man]

Hes not going to the speed challenge.

It looks better than mine. which is nothing.

I never planned on going to the comp. I just ran accross this forum while doing my own playing around with my car. However, I am getting so many requests to go that I may show up last minute. My parents live in AZ about 2 and 1/2 to 3 hours from Cali. If I can see some big numbers with this car, I may fly out there and drive to the comp with my father. But, that is all up in the air. I am not going unless I can see some serious numbers out of the car. As it is, 100 is nothing. But, I just smoke the tires beyond that. I have power, but not enough bite.

Matt

[ajlovering12345]

I never planned on going to the comp. I just ran accross this forum while doing my own playing around with my car. However, I am getting so many requests to go that I may show up last minute. My parents live in AZ about 2 and 1/2 to 3 hours from Cali. If I can see some big numbers with this car, I may fly out there and drive to the comp with my father. But, that is all up in the air. I am not going unless I can see some serious numbers out of the car. As it is, 100 is nothing. But, I just smoke the tires beyond that. I have power, but not enough bite.

Matt


The new body might give you the downforce you need to stop the tyres spinning. I am trying to find somebody who will mold me a lexan body from a model. The body I have at the moment is not functional.

[Mod Man]

It is wet out today. Bummer.

I rebuilt the car this morning (new pinion and spur).

I hope to run it today on 12S.

Matt

[ajlovering12345]

I ran mine today on a big carpark but the jobsworth security guy threw us off. Check my blog for the vid

http://ziggy12345-myspeedattemptcar.blogspot.com/

WAY to much power with the low gearing. You can see the wheels spinning when I blip the throttle.

I have fixed the exhausts and ready for another run

:D:D

[Mod Man]

I just got in from another run. I ran the car up at 94mph and it ran off the road. I have too much nose downforce at speed. The steering becomes hyper-sensitive.

When it ran off the road, my Eagle Tree registered 25 Gs impact force! Also, the car only drew 2200 watts on that run. That is encouraging. Also, I had no appreciable wheel spin. I know that because of the phenominal control I had over the car under accelleration and because of the lack of heat in the tires after the run.

Oh, no damage from the impact! :D

Matt

[ajlovering12345]

Sounds promising!! Can you tune down the steering response?

[Mod Man]

Not easily. It is a downforce issue. I am battling the front to rear downforce bias. I have enough rear downforce, and too much front downforce. So, I am rounding the front to cut down on the amount of air pushing down on the nose.

I will get it!

I am also doing some research on some super exotic, waaaaayyy outside the box stuff. This is getting fun!

Matt

[fasterthanspeed]

How did you mount all the sheets of lexan together?
Where did you purchase .060 lexan that size?

[myndseye]

Are you sure that the CF body wasn't perfect? Sounds perfect to me. After all, to get the maximum speed out of the car, it would be logical that you would not want a lot of downforce until after 110mph or so. Just enough to keep it right side up. In which case, the CF body may have been perfect. If I were you, and I'm not, I'd keep practicing and tweaking with it until I got it as under control as I could, and reserve the downforce game until after it proved to be inadequate in the situation I was planning to use it in. :teacher:

[Mod Man]

If I were you, and I'm not, I'd keep practicing and tweaking with it until I got it as under control as I could, and reserve the downforce game until after it proved to be inadequate in the situation I was planning to use it in. :teacher:


Yup, that is exactly what I did.

Yes, the CF body is very good. It is very slippery and has some downforce. However, once the car hits 100, the tires start to spin, at 110, the tires just smoke. So, I need more downforce with the CF body. Also, the car rolled at 90mph and did some damage to the CF body. It will take a couple weeks to get it finished. So, for now, I threw this together. It is not permanent. But, it works for now and I am getting a good baseline for how much downforce to add to the CF body.

I have another custom body coming soon too.

I got the Lexan from Piper Plastics locally here in Illinois.

I can give you their number if you like.

The panels are screwed together at the edges with Delrin strips.

Matt

[NotWalkinBlind]

the CF body is very good. It is very slippery and has some downforce. However, once the car hits 100, the tires start to spin, at 110, the tires just smoke. So, I need more downforce with the CF body.Did you consider a typical onroad rear wing on wire posts through the body transferring the downforce directly to the rear axle mounts?

[HarryCallahan]

Did you consider a typical onroad rear wing on wire posts through the body transferring the downforce directly to the rear axle mounts?
Don't think the rear axle is independent of the chassis.:)

[HarryCallahan]

Whoops,sorry no i was looking at B4maz's car with the motor forming the rear axle.

[ygguB naM]

Y don't u just use ground effects?

[NotWalkinBlind]

Both bodies are already getting downforce via ground effects.

See the "A new CF supercar is born" thread for more on his CF body.

[Mod Man]

I rounded the nose on my Lexan body with very good results. I need to take a tiny bit of downforce out of the rear and this body should be a very well setup test body.

My CF body will benefit from my knowledge gleaned from this body.

Matt

[NotWalkinBlind]

Re: "rounding the nose"... the word is photos... we need photos. :D

How do you plan to take out some downforce on the rear?

[Mod Man]

I will upload some pics soon.

To take downforce out of the rear, I will shorten the rear deck, thereby eliminating some rear deck upsweep.

Matt

[wagonman72]

Wow it's getting time to run fast again, i can feel it. If the event is here in Cali again you can bet i will be there. This time I will really try to make people mad with my ingenuity in the monster truck class, but you will have to show up to see what I have up my sleeve muuuuaaaahhhhahahaha!!!