Project Viper
 

OK! I bought an Ofna Ultra GTP kit a while ago with the intention of using a huge ducted fan to power it. LSS, that didn't work out. SO- I'm planning this.

Neu 1521/1.5D 1900kV
FlightPower 8s 25C 5000mah (2x 4s)
MGM 12032
RC-Monster motor mount*

There's about $1300 worth of stuff there, plus shipping charges. So as to get this finished before the summer ends and I can't drive it, I'll try to focus my spending power into this one project until it's done.

*The motor mount puts the motor on the wrong side of the car. I must have an old version because BrianG didn't have this problem on his Ultra. I've contacted Mike about making one with the bearing recess on the opposite side so the motor sits in the left rear corner of the car.

Sounds like a real money pit but definately worth it! Cant wait to see pics.

Thanks! I can't wait to see them either! :lol:

Ha, you've got somthing better than pics to look at.

Looks good, just stay away from the minamps packs. Buy a pair of flightpower 3700 25c 4s lipos. That will feed the neu alot better than the minamps packs can, and will most likely cost about the same.

Ya I agree with you their Linc. MA packs are pricey and their amp ratings are bogus...

They were ok, until they raised the prices. Now they are in flightpower territory, and just cannot compare to enerland cell based packs.

Well I've never had issues with MA packs. I like them mainly because I can have them wired to plug directly into an AF Blinky balancer, which is what I have. If I went with the FP packs, although much better quality I know, I'd need to spend $100 on two V-balancers as well. I know MA doesn't match their cells which I think would greatly improve the performance if they were. This is why I stay with the "1p" arrangements of their lineup (4000, 5000). I already have two of the 4s 4000 packs but I know they wont put out enough juice for this car.

You don't necessarily NEED V balancers. Just make your own adaptor to use the Blinky...

Aren't they wired backward though? The blinky wants a +---- for a 4s and I thought that FP was wired like -++++ for 4s. If not then yeah I'll just swap connectors and be done.

Wire color makes no difference in the least. Go by the voltage on the wire, not the wire color.

What I meant was the blinky uses a negative reference. I thought the FP had a positive reference which cannot be adapted to negative since you'd be missing one tap altogether.

DOH! Nevermind. Sorry, huge brainfart there...:slap:
I just drew it out and realized there is no difference. I will get the FP packs instead. Two 4s 25C 5000 packs should do nicely.

lol, it's ok. It happens to us all sometimes. :smile:

You will wonder where the extra power comes from compared to the minamps packs. TBH they are only good for 10th 2wd vehicles, where it is difficult to draw a good load unless you are geared to the moon. I guess that is why traxxas rates their 70mph claim on 8000mah batteries. If you ran 2 3700 fp packs in parallel you would have some serious capability, much more than a ma 8000 pack.

Oh did I mention that the car will be RWD? I already took out all the unnecessary stuff and shaved almost 1/4 pound off the car. Dual-disk brakes also. Single-speed center spool to make things simple.

Here's the body: It has some bite. :mdr:

do you really need dual disk brakes when ur running a spool? ther can be a couple ounces of shaved weight

Maybe not, but I like to over-engineer everything. If it just wont stop locking the wheels up then I'll go down to a single disk.

ahh ok

Some pictures
 

I almost forgot these!
 

I hope you like it because I know I do!

Sweet! Can't wait to see it finished!

Looks sexy :tongue:

*updates*
 

I'm going with a slightly different power system. It will be:

Neu 1515/1.5D-s
FlightPower 6s 25C 5000maH
MGM 12032

:sarcastic: Only half the potential power of the first system, but I can settle for 2500 watts. :surprised:

NICE! Can't wait for vids!

Awesome rig and setup dude.... !!!

Thanks guys!

Hey do you think I should put the 2-speed in it, or is it more trouble than it's worth? I mean, how long would the 2nd gear clutch last? :whistle:

OK! Making progress... I bought the motor. A Neu 1515/1Y smooth can. I figure it will be easier on the system and still be PLENTY fast (and because Mike said it was a good choice). :mdr:

Still waiting for MGM controllers to be in stock. By that time I'll have the cash for it. :smile:

The brakes are done. I'll use both electric and mechanical brakes because the thought of not being able to stop this thing is horrifying to me. :cry:

http://i52.photobucket.com/albums/g4...d/DSC00091.jpg
http://i52.photobucket.com/albums/g4...d/DSC00090.jpg
http://i52.photobucket.com/albums/g4...d/DSC00089.jpg

I also reinforced the body a bit with some fiberglass rod I had.

http://i52.photobucket.com/albums/g4...d/DSC00092.jpg
http://i52.photobucket.com/albums/g4...d/DSC00094.jpg
http://i52.photobucket.com/albums/g4...d/DSC00095.jpg

Next time on Project Viper: The motor is in!

a servo where the front diff goes with a two sided horn that pushes out rods to lock the front wheels for burnouts would be uber cool

That would be cool. Maybe later on I'll try and figure out how. I just want to get it up and running first. The motor/mount has tried to deliver itself twice already but I haven't been here to sign for it! There goes work again, getting in the way of play!

With only the rear wheels braking, you WILL have some troubles stopping it. For the loss in weight I'd keep the 4wd and have better brakes

I may reinstall the 4wd/4wb. I want to see how it act's with 2wd/2wd. It's what I've gotten used to driving with my over-powered Rustler. I think it will drive realistically which, being a physics-minded person, is also what I'm used to. Having two vehicles with different driving styles would most likely lead to more broken parts. I'd expect it to do one thing and it would do another.... crash! :cry:

Something new:

I'm going to try building my own LiPo pack for this car as well. I have some 25-50C 5000 packs lying around doing nothing. There are 8 cells in all, 6 are about the same age. I'm going to cycle all 8 cells at 1C to see which ones would be best to use in the 6s pack.

One more thing:

If I don't catch the USPS guy before work tomorrow I'm going to leave a note telling him to leave the package. I will sign the note so hopefully he will comply...

Hmm where should I start? All 8 of the cells I tested were toast (not literally). The postman didn't leave the package either. So down to the PO tomorrow I go. I need to mail something anyways.

Now I'm just waiting on that economic stimulus check. The IRS may as well make it out to RCM. :lol:

What brand cells were they? And they were all dead?

They were sold by Tanic Packs. They were old (had not been cycled for almost a year) so I'm not that surprised they went bad. The part numbers on them are PF8643150XP.

http://i52.photobucket.com/albums/g4...d/DSC00096.jpg
http://i52.photobucket.com/albums/g4...d/DSC00098.jpg

I disassembled all of the packs so that I could test 1 cell at a time. The first 3 I tested (all from different packs) started at around 3.56 - 3.68V. Not bad right? Except they went down to 3.0V within 20 seconds at a 0.5C discharge?! So I tried charging them. They all peaked to 4.2V in less than 1 minute. :no:

I went down to the PO today and picked up an unassuming white box they had been holding for me. You won't believe what was inside- :surprised:

http://i52.photobucket.com/albums/g4...d/DSC00099.jpg

:yipi:

So began the installation. It went well, the only thing I noticed was that the holes in the bottom of the motor mount weren't tapped deep enough. I had some shorter screws around so NBD.

http://i52.photobucket.com/albums/g4...d/DSC00100.jpg
http://i52.photobucket.com/albums/g4...d/DSC00101.jpg

I had to file out the bump-start hole to fit the wider plasitc spur.

http://i52.photobucket.com/albums/g4...d/DSC00102.jpg

It's looking pretty good now. :yes:

http://i52.photobucket.com/albums/g4...d/DSC00103.jpg

5.5mm bullet connectors were soldered onto the motor leads. I like shiny things!

http://i52.photobucket.com/albums/g4...d/DSC00104.jpg
http://i52.photobucket.com/albums/g4...d/DSC00105.jpg

Only two more pieces and the puzzle will be finished. Unfortunately, these pieces will cost almost $800. :oh:

http://i52.photobucket.com/albums/g4...d/DSC00106.jpg

This is a 22T pinion against the 51T spur. There is plenty of space to fit the 25T pinion I bought, too.

http://i52.photobucket.com/albums/g4...d/DSC00107.jpg