Some ideas/brainstorming for a 1/7 scale on road car build

[lincpimp]

Was cleaning up and found my Hot Bodies Lightning Street and decided it was time to make something out of it. Maybe use it to jump start my rc interests again??

Anyways, the LS (lightning street) is basically a HB buggy with a longer chassis. It has a 2 speed center spur with 46/42 gears. Single mech brake setup and regular buggy 43/13 diffs. Uses 1/8 buggy wheels with 17mm hexes.

Looking at my motor inventory I have a few options. A 2200kv flux motor, 1521 1y neu, 1717 cc motor, 1521 2y and 1521 2.5y.

I do have the RCM 2 speed adapter and a few losi and rcm pinion gears to use with it, 26/30 would mesh with the center gears and be the highest gearing I can swing with off the shelf gears. 16/20 would be the lowest gearing.

Would use a MMM and a turnigy 5k 6s 40c lipo. I have those at hand.

With the 2200 and max gearing I get 104 in 1st gear and 131 in 2nd. Might be overgeared for that motor. Lowest gearing gets me 64 in 1st and 87 in 2nd. Do we think the 2200kv flux motor will pull this gearing? I know the 1515 sized motor is quite potent and this car will not be much heavier than a truggy with alot less wheel/tire weight...

I like the 2200 flux motor as it can be easily adapted to this chassis by attaching it to a flat plate and then threading that plate to accept the nitro motor screws. The other motors would require some sort of L bracket or maybe get mike to make me a center diff bulkhead to fit?

I could go to the 1521 1y and gear up and get similar speeds with moroe motor power. Unless I can find a suitable esc the 1521 2 and 2.5y are out. TThe 1717 could be used, but I have it earmarked for the 6x6 lst...


1521 1y with mn and max gearing on 6s:

min gearing: 46 1st, 63 2nd
max gearing: 75 1st, 95 2nd

The more powerful 1717 would be about the same, as it has a similar kv, and would likely pull the max gearing in 2nd, as long as the MMM can handle the load. Pretty sure that 40c turnigy can swing it, if not I can make a 6s2p 6400 pack that will.

Thoughts???? Insults???

[What's_nitro?]

A 1/7 car, a 1717 motor... I'm starting to notice a pattern. Too bad the MMM can't handle 7s LiPo. Maybe the ICE HV 170?

[What's_nitro?]

Kidding aside, the car is 4WD right? Based on how easily a 2200 lights up the tires on 6s in a 1/8 4WD car (my GTP geared for ~75mph) I think it would be right at home in a 1/7.

[JERRY2KONE]

For what you are leaning towards I would think the 1717 is out just because of the added weight issues. The 1521 should be right on track for descent speeds for an onroad vehicle, and still give you plenty of power to play with. There are several ESC choices that would do you right, but figuring out exactly which one would work best for your taste will be your toughest decision for sure. Maybe a very capable size MGM would be good for the job if you can work the setup issues and aford the cost. If so I would have two of them so you have a backup on hand. Remember James if things go right we should be in Prague, Czech Republic soon.

FYI By the way I still have not seen those motor mounts for the Neu 1527.

[lincpimp]

Originally Posted by JERRY2KONE

FYI By the way I still have not seen those motor mounts for the Neu 1527.

Strange, mailed them out the next day after we spoke. They did go in a small envelope, so maybe that takes longer to get to you?

[lincpimp]

Ok, so I will try the 1515 2200 motor 1st. Need to get all of my gearing options together and make an order with Mike. Turns out I will need but the 16t and 20t gears for the 2 speed adapter....

Will mock it up and take some pics. Guess the servo, esc and motor will go on one side and put the battery on the other. Still think the battery will be heavier than the other components combined.

So should I mount the battery at the front of the back? I am guessing the front, maybe?

[Overdriven]

I like to mount everything closer to the front. I've found it helps increase steering, especially on power. Then again I like alot of steering because I like getting sideways.

[lincpimp]

Originally Posted by Overdriven

I like to mount everything closer to the front. I've found it helps increase steering, especially on power. Then again I like alot of steering because I like getting sideways.

I thought the same thing. I have always liked to put the weight over the front tires as much as I can, as it seems to help steering, especially under power. You do have to use a stronger steering servo, but I have quite a few jr 9100t servos.

I also will run mech brakes, so I will need to mount the brake servo somewhere, likely just in front of the center diff on the motor side.

Pics will be up tomorrow, had pc issues all day today at work...

[bigboi146]

I think the lightning would be an awesome platform for what you want to do. As far as weight distribution goes I agree with the battery going somewhere toward the front of the car. Can't wait ti see some pics of this thing!

[lincpimp]

Ok, did a mockup. Will need to move the steering servo over to the motor side, will likely make a servo plate that will hold the steering servo and the brake servo. Esc will go next to the motor at the back, as in the pic.

The motor is not the correct one but it gives some idea of placement.

Battery tray will go where the steering servo currently is. Will overhang the chassis slightly in the middle due to the spur location. If I had a slightly shorter battery it would fit infront of the spur and behind the steering cranks but oh well...

Current 2 speed setup is 42/49, mocked up with a plastic 49t gear, the other gear shown in the photo is a mgt steel 49t spur that I need to have modded to fit the 2 speed assy. I was going to run 18/25 pinions, but the 42/25 gearing would be over 110mph with the 2200 motor. Will stick to 16/20 gearing and run the stock 46t 1st gear spur and have top speed around 90mph.

If I was to use the 1521 1y I would run the 49t spur for 1st and the 18/25 pinions. If the 2200 cannot handle the load I will have to switch it up. Will require a much more elaborate motor mount...

So I will stick with the 2200 for now. People say they are great motors, and I did have good success with one in an lst on 5s... Seeing this thing shift into 2nd gear around 55mph will be interesting. Will need some serious brakes, thinking a high torque servo for the brakes, and another for steering. Luckily I have a few jr 9100t servos laying around!

[snellemin]

Starting to look interesting. That will be one hell of a beast.

[lincpimp]

Originally Posted by snellemin

Starting to look interesting. That will be one hell of a beast.

I hope so...

Just curious. What motor is that in the pic? Think I could make out 1521?

And also, where'd you get that 2 speed pinion adapter? I really need to get some of those.

[lincpimp]

Originally Posted by Dj_Sparky

Just curious. What motor is that in the pic? Think I could make out 1521?

And also, where'd you get that 2 speed pinion adapter? I really need to get some of those.

Motor is a 1521 1y finned. 1600kv and it has enough power to move my 12lb lst around geared for 45mph or so.

The 2 speed adapter is from the rcm store. Uses lst pinion gears, or (preferably) rcm pinion gears. The rcm gears are hardened and superior to the losi ones. Great products, tailor made for conversions like this!!! Thanks Mike! In your face Tower Hobbies!!!

Need to order some from mike, just want to make sure that the sizes I need will fit with the flux motor installed and not touching the rear center bulkhead.

[What's_nitro?]

Looking good... Might I recommend relocating the steering servo to the left side so that the battery can go in the front right to offset the motor?