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Nic used the Bullet Wedge body from Custom Works (one of his sponsors). And yes I am totally serious. I have two new bodies I am not using. :)
The Bullet Wedge is totally symetrical. Matt |
Hmmm, ok. That's tempting, and thanks for the offer, but I'm thinking that the Bullet Wedge might have a bit too much downforce for LiteSpeed once it gets up to speed? The Camaro Open shell that Lutach linked to looks less aggressive in terms of downforce, so that could be an option, and there's also another low-drag shell that I'm looking at getting but waiting for more info on.
You wouldn't think that sorting out a shell would be such a hassle lol! But at these speeds, every detail matters I guess... :) |
wait your planning on using a neu with 4500w right? thats what your "litespeed" thing says... thats over 6hp... the car stock weighs only 2.67lbs... thats a power to weight ratio of like 2.258hp:1lbs... thats unheard of. how will you get power down. its a sick idea but i think your looking at way too much power. the perfect car would have a 1:1 power to weight ratio... what kind of gearing are you going to be using? and can the f103 take any standard 48p gear?
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The thing is, the motor can chuck out 4,500W (very roughly for a short time period) if it *needs* to, to achieve a certain speed (like to get those last few mph out if it hits over 140). For most of the acceleration curve the motor will suck quite a bit less current as it's under less load, making less power as a result. I should be able to use some programming tricks on the React to get acceleration a bit more manageable, and the F103GT can take a variety of 48P spurs. The tyres will spin before a spur strips, so that shouldn't be an issue. :)
By the way, the motor pod plates have been re-designed a bit to lower cost (Metal Man, you were right in saying I should enlarge the radii lol) and also to get rid of some mistakes in my design lol: http://img.photobucket.com/albums/v6...peedPod2-1.jpg http://img.photobucket.com/albums/v6...peedPod1-1.jpg |
i think i found my new project. only i will probably use a mega motor instead of a neu... what kind of voltage do you plan on running?
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For the shell, is looks important? I'm looking at options for my high-speed project as well and thought I'd try making a body out of 1/16" thick lexan for strength. Two vertical pieces (one on each side to act as a sort of straightening rudder) and a curved middle somewhat shaped like most high speed bodies (but without the added details) to provide the downforce. Won't be pretty, but this would be just for high speed runs where function is more important than form IMO. For more normal driving (50-80mph), a normal body would work and look better.
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Looks aren't all that important, but aerodynamics are pretty complex as you can imagine so a properly designed, moulded shell is the only practical way for this car IMO. Shells with good aero properties for this application just often happen to look attractive too, lol. Making a shell sounds interesting...it might be an idea to do some research on basic aero before designing something though. An important property at high speed is rigidity...if the shell starts wobbling about because of the air pressure, you've got problems :S. I'd say a one-piece, moulded shell would be better, but I'm not saying it can't be done... give it a shot! Post a topic on it mate...it'd be interesting to see how you get along. :)
RevRacer, personally I'm going to be running 6S. Sounds like an interesting project! :) By the by, I've just placed an order for a Windtunnel Racing XHS velodrome shell...I'll post more info and some pics when it gets here. I'll probably also get hold of a Custom Works Camaro Open shell as alternative to test...the more the merrier lol. :) |
Yeah, rigidity is very important at high speeds. But I can't find any shells that I think are appropriate for my 8th scale conversion, so I think I'll have to make my own. The plus side is that I can make it any thickness I want. If 1/16" thick lexan isn't enough, I could go with 1/8", but that's seriously thick! Even 1/16" is ~1.6mm thick!
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Its all about rolling resistance, momentum, and wind resistance. Tall narrow tires, a long skinny body, and a low Cg (either through weight, or by using aero to achieve it). Look at land speed record vehicles. They are NOT shaped like a lemans car (ie., glorified ferrari/mclaren/etc). Jet bodies are another example. Long, round, and narrow.
If you could get into the programming, you'd want to use as little of your available juice as possible to get up to a certain speed, then crank it up for the high speed burst. Maybe gearing it so that it'll barely get out of its own way to start - as long as you can up to speed and shut down prior to thermalling........heck you might be able to do this without spending much. Maybe spending the money on some custom wheels and a build your chassis based on those land speed vehicles....now I've talked myself into possibly trying one of these! |
Here is a picture of my 1/16 inch thick lexan body. It works great (alot better than it looks).
Matt |
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Oops, here are the pics.
Matt |
That's so sweet! But you have 1/64" too much ground clearance. :lol:
What did you use for the "rails" inside the body? |
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mod man is that the record tc3?
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The rails holding the panels together are 1/4 inch delrin strips. Matt |
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No, they are made by cutting the profile with all curves out of a flat panel. There are three strips screwed together to give the final shape. It is heavy but strong.
Matt |
That looks pretty nice! It must weigh a bit like you say, but with the power in your car, that can't be a big problem. :) I'm going to try to reinforce my shell(s) with carbon/aluminium rod, and maybe expanded foam. Whatever lends itself to the task.
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Actually, stiff foam works wonderfully for reinforcing the body. I use foam kneeling pads available at any garden store. That foam is ideal for reinforcing lexan bodies and making bumpers. It also accepts CA wonderfully.
Matt |
Cool! Thanks for the tip, I'll probably try that out. :)
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Daggerthrasher. I have a power calc spreadsheet from B4maz that you can use to calculate power required. I'll send you a copy if you PM me your email.
I was using some figures for your car and to get to 150mph in 10 seconds covering 1100ft with a 0.7g acceleration rate you will need around 1600 watts. This is a lot lower than you have calulated. Let me know how you calculated the power requirements and I'll check the spreadsheet Cheers |
Hey Ziggy! Don't worry, I already have that spreadsheet...but stupidly, I only have Works Spreadsheet and it won't open it right. It opens, but without the graphs etc (ironically I can view the whole thing fine on my phone, but not edit it). So I've not been able to really scientifically come up with a requirement. Just out of interest, what car specifications did you put into the spreadsheet?
I've just based my power requirements off of wht other people have run. I've heard people say you need all sorts of different levels of power to reach a certain speed, so I've just gone with a setup that will definitely have enough power; if it's a bit hot to handle, I can dial some of it out via the ESC and my radio. It's all dependent on current, anyway...with "only" 6S LiPo, it should have the uncontrollable bursts of power tha a truly HV system might, but as the power requirement goes up,the cells can just push out more and more current. That's my theory anyway lol! Thanks for taking the time to use the spreadsheet file though...some more info on what you put in would be really useful. :) |
Here is a heads up for you. A rear wheel drive 2wd speed car wont work even with a gyro.
Take all the electrics out and put it into an Xray and you will get 145mph. If not then you will b lucky to hit 50 with that car. Cheers |
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Guys, I know a RWD car is trickier than a 4WD car for obvious reasons. But by no means is it impossible...Nic Case has proven this himself with the RWD oval car he used for the unofficial 160mph speed run. With the right setup, this is do-able. :)
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I spoke with Nic about the 160mph run and it was slower than the previous run. The radar gun messed up
Cheers |
I figured as much, but although it was a slower run, it still must've been over 100 for people to think it was 160. The thing is, I've still not spent all that much cash on this car yet, so I might end up changing chassis but I don't know. The thought of having a more inherently stable 4WD machine is tempting. But RWD is most certainly possible IMO.
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I think as long as the body provides enough front downforce to keep the front wheels in contact with the ground you'll be fine. 4wd can still spin-out if you have too much power, which you will, of course. The only other issue would be steering and that's where the downforce would come into play. Besides, the power going to only 2 wheels will be more efficient and thus give more speed. Ever wonder why AWD cars get bad mileage?
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Any update on the project?
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Thats a no then
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Any updates lately? Subscribed!
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This project is dead
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Great designs take time. I wouldn't count it out just yet.
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Hey guys,
Thanks for the interest! But yep, I've decided, reluctantly, to scrap the project. I really did want to complete it and compete with it, but for reasons which I can't really go into here, I decided it'd be best to quit it. Again, thanks for all the interest and compliments, they really mean a lot. Perhaps I'll have another crack at a speed record car in the future. :smile: |
good luck..im also shooting for a world record in MT class...im designing a similar underbody component ( like F1 racing) that enables downforce on the chassis..my platform is a heavily modded 3905 EMAXX..much heavier than your setup- so im utlizing brute force as my main design feature!
good luck larry d |
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