New hi-speed project - Page 5 - RC-Monster Forums

ssspconcepts · 01.03.2008, 07:57 PM

Quote:

Originally Posted by myndseye

Seems we all have the same idea. IGT on 6S of TP V2, geared 44/25 thanks to Mike. Powered by a 224 MGM and a Neu 1527 1D. I dont have the motor pictured in this one, but it just dropped right in. Had to make sure the motor wires were at the top though.

Just curious is the Pro kit or RTR kit?

speedracer1129 · 01.03.2008, 08:19 PM

Hey Guys,

I also have a IGT I am setting up for high speed. All I am missing is the motor. However, I haven't set it up as I am stuck on the brake setup. I wanted to run a Mega Motor setup to maintain the stock radio tray and mech brakes, but there motors are to small in KV for a speed car. So my question is how bad is it on the ESC when you use brakes in a high powered BL setup with a heavy car?? Can I utilize drag brake safely without spiking voltage to the ESC as this would be my next option??

BrianG · 01.03.2008, 09:23 PM

As long as you stay within the voltage and current specs of the ESC, you'll be fine. The ESC will heat up a bit more, but should be fine. You could add a few more low-ESC capacitors to the battery leads of the ESC as close as you can to the ESC. That will help a bit...

The only reason I'm using mech brakes is because I want to use the 2 speed and the centrifugal clutch makes it so I can't use elec brakes. If it wasn't for that, I'd use elec brakes too because it's simpler and lighter (less parts).

Curious: Why can't you use mech brakes?

speedracer1129 · 01.03.2008, 09:41 PM

Quote:

Originally Posted by BrianG

As long as you stay within the voltage and current specs of the ESC, you'll be fine. The ESC will heat up a bit more, but should be fine. You could add a few more low-ESC capacitors to the battery leads of the ESC as close as you can to the ESC. That will help a bit...

The only reason I'm using mech brakes is because I want to use the 2 speed and the centrifugal clutch makes it so I can't use elec brakes. If it wasn't for that, I'd use elec brakes too because it's simpler and lighter (less parts).

Curious: Why can't you use mech brakes?

I plan on using the 2-speed as well. You brought up a good point that the brakes will not work with a 2-speed. The reason why i can't use mech brakes is that I will have to cut out that section of the radio tray for the RCM motor mount. Any other suggestions??

lincpimp · 01.03.2008, 09:46 PM

You can always remake the servo tray to position the brake servo farther away from the center diff and motor mount. I was going to use a low profile servo and place it above the dirt guard on my hyper7 buggy and just use longer brake linkages.

BrianG · 09:51 PM

^ +1 That's what I plan to do with the GTP, except I plan to make all the non-frame parts out of fiberglass for weight, strength, and cost (compared to CF).

Yeah, if you use elec brakes, you are stuck with single speed. For two speed, you NEED mech brakes.

speedracer1129 · 01.03.2008, 09:50 PM

If I had the means that would be an option, but since I don't....... That is why I like the Mega Motor setup.

lincpimp · 01.03.2008, 09:58 PM

Quote:

Originally Posted by speedracer1129

If I had the means that would be an option, but since I don't....... That is why I like the Mega Motor setup.

You can always use mike's motor mount on the front diff bulk and place the motor where the gas tank would be across from the steering servo. The place the batteries on either side at the back, I may do this on the hyper, and not have to mod the servo tray. Not sure what to do, it really depends on battery size.

speedracer1129 · 01.03.2008, 10:14 PM

Quote:

Originally Posted by lincpimp

You can always use mike's motor mount on the front diff bulk and place the motor where the gas tank would be across from the steering servo. The place the batteries on either side at the back, I may do this on the hyper, and not have to mod the servo tray. Not sure what to do, it really depends on battery size.

I am also thinking about that option, except that it looks very tight to fit a motor. Anybody know how long a NEU 1512 or 1515 mtor is??

speedracer1129 · 01.03.2008, 10:19 PM

Never mind, I just figured it out. 1515 is about 68mm

BrianG · 01.08.2008, 12:43 PM

Well, I ordered the Ultra GTP from nitrohouse yesterday. I got the RTR version so it has more "stuff" already on it (body, servos, etc), and I can sell the motor/pipe to recover some of the cost. Anyone wtb a .28 engine with pipe?

Plus, the listing says it comes with the two speed option (normally ~$100 by itself). No other place lists it as coming with the 2 speed, so I dunno if that was just a misprint - I hope not.

When it arrives, I'm gonna start making the fiberglass brake servo mount/ESC mounting area to give me more room for the motor. I'm gonna hold off on making the battery tray until I figure out exactly which 6s lipo pack I want to use.

Pictures are sure to follow...

BrianG · 01:53 PM

Yay, the car came in! Despite Ofna's site saying it only comes with the single speed tranny, it actually does come with the two speed.

The slicks will have to be replaced with foams or something as I can tell they're gonna balloon like crazy. Quality is really nice at first glance.

It's gonna be a huge vehicle though! The chassis is normal size, but there is a lot of space in the front and rear ends of the shell. I'll be able to make a little shelf in those areas to add weight as needed for traction and to help compensate for weight distribution somewhat.

The first thing I'm gonna do is make a new brake servo plate. The existing one leaves no room for the motor. So, I'll fab up a fiberglass sheet and cut out a new plate. Don't know yet if I want to just push the servo out to the side more or re-orient the servo so I have room to use a motor adjustment tool.

The receiver box acts like part of the rear bulk support, so I'm gonna have to fab up a new system for that since it's coming out. I'll probably use aluminum for strength. Fiberglass is strong, but flexes too much.

There will be plenty of room for lipos. I measured roughly 210mm long X 60mm wide X whatever mm tall, and those are conservative measurements.

I won't be able to hit the speeds I want with the stock spur clutchbell options. So, I'll have to mix and match the spur gears as needed. Because the spurs are specific to 1st and 2nd speeds, these are my options:
1st gear: 49T and 47T
2nd gear: 45T and 44T
Also, I need to find spur/pinion combos that will maintain the proper mesh for both first and second speeds. So, I was thinking of using the 49T spur for first, and the 44T spur for second. If I use a 20T pinion for first and a 25T pinion for second, I can attain theoretical speeds of 93mph and 130mph respectively. A little short of what I was hoping for, but should still be fun!

Sorry, no pictures yet. The camera is currently unavailable.

BL_RV0 · 01.12.2008, 12:39 PM

u should enter it in the Radio Controlled Car Action's Second Annual Fastest RC Car Competition.
check out the vid, its nic case with his brushless tc3 winning. 134.4 mph.
http://youtube.com/watch?v=yI5xLNeNDO8

BrianG · 02:10 PM

Not sure if I can get it that high. If I can get a 26T pinion made and use Mike's two speed pinion adaptor thingy, I should theoretically be able to hit 126mph in 2nd (1st up to ~95mph). But, I'm sure there will be tons of air resistance and friction at that speed (if the mechanicals hold up). I might use 10s instead for some really high power output because I think I'll need it! And I'm gonna need some serious front downforce. I don't want to think about what would happen if it took off at that speed!

I noticed that the brake on the GTP doesn't have return springs, so I just added those. I also lengthened the brake actuator arm for more servo range of motion and added a spring to the linkage so I have a little more braking control.

suicideneil · 01.12.2008, 06:49 PM

Stick some RCM stickers on the shell, that should add at least another 10-15mph, easily.