...Just trying to do this all smart-like
Couple of changes to the project, after to talking to Nic (Case) some and looking at time, money (and how much could be lost if it all goes wrong), and my general lack of experience concerning speed run cars I think I am going to cut my teeth some on running the car on the stock chassis (a bit of a Vassmar clone).
I think I need some more first hand experience from running a car that fast and finding all the limitations of the TC4 and determining what exactly will be the best measures to take in improving the car (instead of going head on into building a streamliner without any first hand knowledge of what may or may not work). I also would like to do some velodrome races and think a stock wheelbase car will probably do better.
Now I am not wussing out and will be still developing the streamliner along side running the stock wheelbase car as running one in the "open" class is where I want to be in a year or so but figure I better walk a bit before I run.
I got some new parts the other day too...
Got a GY401 gyro, it is supposed to be a bit faster than some of the others so we will see (got a good price from the LHS on it too) , also picked up a CC-BEC. I need to gather a few more parts as cash flow allows and hopefully will be up and ready to run by the time my BSR tires get here at the end of February.
Friday, January 16, 2009
I am building the car to run under ROSSA rules (Rules) for the "modified electric" class. This allows me to build the car with eventually moving up to the "open" class in mind but is based around a bit more affordability, which is important given the present economic condition.
Vehicles are classified as Electric Modified as long as the meet the following criteria
·Single electric motor any size
·Max cell capacity 15V 5000 mah
·Max length 1000mm
·Max width 300mm
·Commercial or custom chassis
Given all that I am designing the car as a lengthened streamliner with lexan upper and lower body shells to completely enclose it for maximum aerodynamic efficiency. Dimensions I know at this point are...
Overall Length: 32"
Overall Width: 8"
Chassis Length: 23"
Overall Height: 5.25" (may change if I can get the shock towers significantly lower)
The plan is for the chassis to be .125" carbon fiber (or Garolite if CF proves to be cost prohibitive) that will be have material removed to be even lighter. The lower tub of the body is also going to be a stressed member of the chassis (hopefully allowing me to remove more material from the chassis itself). The picture above have the basic layout, thing will have to change for mounting points and surprises later but as soon as I get all the mounting points laid out on it I will cut a prototype piece out of aluminum probably (because I have that available on hand already) before I do a final in CF.
At first I was not really concerned about weight as a speed car needs a bit of weight to stay on the ground (or lots of downforce which slows you down) but I think it would be better to build the car as light as possible (while keeping it rigid enough of course) and adding weight as needed in the form of stick on weights. This way I can position the weight where it will be most effective.
For electrics at the moment I am going to use a Futaba 3pm (modded for extra range) for control and most likely with a gyro for extra control. I am planning on using the Mamba Max 7700 on 4s lipo, which you are not supposed to per Castle but will work for a couple of runs and then let it cool. It is not as exotic setup as I would like to run but I think it will be a good affordable setup that will go fast enough for this first year of competing to get a good idea if the overall design will work (and there are a few guys getting some incredible speeds out of the MM 7700 on 4s anyway).
Gearing is still in the air as it will require a fair amount of testing but for a starting point though I will most likely begin in the 30/68 and go up from there as there have been others getting good results with that. There is a fellow known on various rc speed forums as Vassmar that has been running 35/68 (48 pitch) on his stock length, commercially available bodied TC4 with the 7700 motor and 4s and is claiming runs over 120mph. If I need to go bigger on the pinion I guess I will have to go custom as I believe 35 is about as big as you can commercially get.
Tires I am planning on running BSR velo sedan tires (which reminds me I need to call BSR about getting some of those ordered).
Anyway I will add more info as it comes along but right now I am still just planning, measuring, and trying to get parts together.
Wednesday, January 14, 2009
As I begin my quest to become (as some of my friends describe) the fastest nerd on the block I can't help but to wonder...what am I getting my self into. That does little to slow me down though, turns out I am a glutton for punishment.
I am starting with an Associated TC4 touring car that I will be modding with a longer chassis, streamlined body, lots of power, and big 'ole tall gears (specs to be added as I figure them out). I couldn't think of a good name for the car that didn't sound lame so I am going all alpha-numeric with CSC-1 which stands for, (SUPRISE!) Chappell Speed Car #1
The plan is to hopefully get it all together and working in time for the ISC competition:
They haven't released the date of this years race yet but I am hoping for it to not come too soon, Har Har!
Anyway I hope you enjoy my trails and tribulations and hopefully my project will inspire others to come play with us. With any luck I will have a really fast car at the end of this or a spectacular lipo battery fueled explosion, I figure I am a winner either way.