New hi-speed project - Page 3 - RC-Monster Forums

lutach · 12.26.2007, 11:57 PM

I ran the 1521/1Y with 10S 4600mAh TP and the Schulze 40.160 and it did not pull that many AMPs. The 1521/1Y was spinning at around 55000rpm. The only problem was the drive train. I drew a crowd of people at the parking lot looking at the truck fly from one side to the other. I still have to try my 1527/1.5Y, but I'm waiting for my custom 58.8V packs and I might have to trim one of the braces from the truck to make the 1527 fit.

BrianG · 12.27.2007, 11:13 AM

About the amp draw: I won't be spinning the motor at ~55krpm all the time - just when I'm trying to hit really high speeds. For normal play, I'll be gearing down and/or using less voltage and/or using the EPA to limit motor speed.

Still not sure about whether to use two speed or not. But, I can decide that on-the-fly since the single speed/2 speed setups are interchangeable. I just have to remember to use mechanical brakes for the 2 speed. 2 speed would be easier on the motor since it won't have to pull such a tall gear on take-off, but the 1515 or 1521 are pretty powerful motors. My 1512/2d on 4s has no problems pushing my overgeared buggy to around 55mph, and I'm going to try to make this vehicle as light as possible.

For the motor mount, I will probably see what Mike has already and go from there - or make my own. Balance will be very important for something like this, so I have to really do my homework on device placement. The plan is to do a typical setup where the motor is on the steering servo side, battery on the other, ESC/Rx wherever it will fit. I'll probably leave the brake servo where it is, just pushed out to the side to allow room for the motor there.

Yeah, the yusa models are cheap, but I tend to break the same part so I don't want to have 5 chassis's laying around.

How long have they been around? I don't want to buy myself into obsolescence.

jhautz · 12.27.2007, 12:30 PM

I just did a little part number research for the center dif uprights on the GTP. They are different than the Jammin center dif mounts so I dont know if the Jammin buggy motor mount will work. If you can give me center to center measurements on the center dif screw holes I can check it against the Jammin buggy motor moount I have in my DM1.

Big House · 12.27.2007, 12:53 PM

JHautz,

I did the same checking and cam up witht he same thing. I am hoping the OFNA online help comes on soon. I am going to see if the diff units are interchangible. If that is the case then the CRT mount will work.

Big House · 12.27.2007, 01:06 PM

Just checked with Ofna and the diff unit in there is the only one for that car. Hopfully Mike can come through with a mount for this one.

BrianG · 12.27.2007, 01:12 PM

I'm not too worried about that because I can make my own mount if need be - something like what I did for the CRT.5, except use thicker aluminum. Can't forget to make the mount capable of retaining the mechanical brakes...

BL_RV0 · 02:20 PM

hey BG, how about you use lutach's 200a controller when it comes out or maybe a CC HV110, and a neu 1527 1d (2160kv), and 12s 25c lipos (polyquest)?
esc: $270
motor: $433
batteries: $776

how does $1476 for a setup sound?

squeeforever · 12.27.2007, 02:47 PM

Why not something like a 2230 on 10S using the HV85 or HV110. The 2230 might be better for RPMs since its got the are diameter rotor for the torque needed, but also a shorter rotor which would be better for high RPMs. Basically, less rotating mass.

lincpimp · 12.27.2007, 02:53 PM

Quote:

Originally Posted by BL_RV0

hey BG, how about you use lutach's 200a controller when it comes out or maybe a CC HV110, and a neu 1527 1d (2160kv), and 12s 25c lipos (polyquest)?
esc: $270
motor: $433
batteries: $776

how does $1476 for a setup sound?

I agree that HV is the way to go. I am going to order a great planes 60amp hv esc and the programming card. I will try it on my tmaxx first, 10s lipo on a 20xl feigao should be ok, do not think it will overdraw the esc.

Brian, the use of smaller batteries and more cells would probably be cheaper. I have seen 15-20c 2100mah cells go for $10-$15 per cell. And I am sure that a 12s2p setup of those cells would be able to get you about 4hp. Run that thru a decent hv esc, castle, knotronic, etc.

I am actually reconsidering a hv setup for my yusa car. I will test it on 4s with the 2600kv motor, but may sub in a 1300kv and run it on 10s lipo?!?

I agree on parts availability, usually there are one or two parts that break fequently, so you would end up with quite a few rollers!

BrianG · 12.27.2007, 03:17 PM

I would like to go HV, but was thinking the dimensions of a many-celled pack would be physically prohibitive because of the thickness. I'll have one whole side of the chassis for the length, but think I will be width and height limited. Nevertheless, I won't be purchasing any of the electronics or batteries until I get the vehicle in my hands, the motor mount made, and the rest of the layout sketched in.

I'm really anxious to start this now. Might have to check my bank account to see if I can shift funds around a bit.

captain harlock · 12.27.2007, 03:47 PM

I think a car like serum's past Serpent onroader would be nice. The only downside is the handling with brushless motors. You might need to use some sticky type liquid on the foam tires to keep the car on a straight line and avoid spinning.
The Kyosho Inferno based on road cars and the Ofna one's are great, but 100+mph would be easier to achieve with the 1/8 on road cars.

BrianG · 12.27.2007, 04:23 PM

The Ofna is an 1/8 on-road car. Besides, this isn't about "easy", but about the challenge and fun (and occasional frustration and not a little swearing).

lincpimp · 12.27.2007, 04:30 PM

The swearing is my favorite part, right after the cogging!

I tried for better balance by placing two battery packs (your old 2s2p milwaukee cells Brian!) on either side of the chassis, one where the radio box was and the other where the fuel tank used to be. This gives me a good side-to-side weight distribution and a little more weight on the rear than on the front. This setup worked best on the tamiya and I hope it will work well on this car too.

BrianG · 12.27.2007, 05:15 PM

Luckily, I've never had a vehicle with cogging, but that's probably because I overengineer stuff. The swearing mainly comes from custom fabbing something only to find that it is 2mm too small!

Going with a pack on each side will severely reduce the amount of room for the other components, so I probably won't go with that for this, plus I want to keep it light.

gimpygolden · 12.27.2007, 07:20 PM

I have the OFNA roller with a NEU 1512 2.5d on 5s gear'd 18/51 was alot faster than my brothers Inferno GT(supposed to go 50mph).

This car is going to be gear'd 25/51 and settings on the Quark125 toned down. The car has way to much torque.Just a short blast of full throttle balloons the tires so bad they just peel off the rims.
I already have foams for next year,but I think I might be pulling this setup in favor of a NEU 1509 and Quark 80b. on 5s to try to slow this thing down as it's a real handfull.
I'm pretty sure if you want 80mph it is easily doable but good luck keeping it in a straight line.