Felony Aero past 100mph.

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Scoticus

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Arrma RC's
  1. Felony
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I'm running the protoform c8 on my felony and I'm having trouble keep it on the ground after 100mph. I haven't tried side skirts or the infills yet and I was running the full wing because hoons have no traction. Last weekend I had some of the most stable passes, good weather and no wind, but my last run she went airborne. What are some tips or tricks to keeping the c8 felony on the ground?
20210926_124342.jpg
 
Face down ass up. Take the springs off the rear and lock them all the way up using fuel tube.
That was a great explanation.


He means that put the front down as low as possible as it will lift when you are on the throttle due to the back squatting. Put the preload all the way up in the rear and put some nitro fuel tubing on the shock shaft (outside of the shock body). You can set the front preload depending on how hard you brake. Just make sure if the front scrapes, it's just a bit. Color is nice on the body. It's destroyed now tho.
 
That was a great explanation.


He means that put the front down as low as possible as it will lift when you are on the throttle due to the back squatting. Put the preload all the way up in the rear and put some nitro fuel tubing on the shock shaft (outside of the shock body). You can set the front preload depending on how hard you brake. Just make sure if the front scrapes, it's just a bit. Color is nice on the body. It's destroyed now tho.
I had a pretty aggressive pitch to the stance on these run before the blow over. Maybe I had the rear too soft causing it to squat?. I haven't used any fuel tubing on it but I had the droop screws set so the nose was low and the rear high with a lot of preload on the front and about mid way on the rear.

The colors came out that way because I am bad at painting 😂
 
The body is rather soft. Make sure there is not a gap between the body and the front lip.

Like Jon mentioned make sure the rear is high up and barely moves at all. A simple trick (if you don't feel like doing the fuel tube trick "tried true and proven") is to loop some zip ties around the shock shaft so that the rear cannot compress. Also turn the spring collar all the way down to tighten the spring pre-load as much as you can in the rear.

You may need to flatten the rear wing. Those soft plastic wings like you have there may be folding back at speed and causing the issue.

People often also re-inforce those bodies or just go with delta plastick speed run bodies for that reason.
 
The body is rather soft. Make sure there is not a gap between the body and the front lip.
Like Jon mentioned make sure the rear is high up and barely moves at all.

You may need to flatten the rear wing. Those soft plastic wings like you have there may be folding back at speed and causing the issue.
I had no gap from the body to the lip but I am now thinking the rear shocks were too soft. I tried to make another pass with the wing cut down where it broke but it was uncontrollable. Do you think with a stiffer rear and skirts I can avoid this in the future?
 
I feel for you I rolled my C8 Felony Sunday. Not a speed run, did a 180 at 25 ish caught something and on the roof she went. 1hr wet sanding and polishing. Looks better. My front nose of the bumber rest over my splitter and the splitter is 1/4 inch off the ground at most. My rear spoiler I reinforced with a layer of carbon fiber and epoxy. Little late but going forward.
 
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I feel for you I rolled my C8 Felony Sunday. Not a speed run, did a 180 at 25 ish caught something and on the roof she went. 1hr wet sanding and polishing. Looks better. My front nose of the number rest over my splitter and the splitter is 1/4 inch off the ground at most. My rear spoiler I reinforced with a layer of carbon fiber and epoxy. Little late but going forward.
Big thing for me will be figuring out the wing on this one. I might just cut the back off of my next one and do a limitless style wing. My body is a bit cracked now but I will probably use it to dial it back in. Just sucks that I can't seem to get just the wing from protoform.
 
Big thing for me will be figuring out the wing on this one. I might just cut the back off of my next one and do a limitless style wing. My body is a bit cracked now but I will probably use it to dial it back in. Just sucks that I can't seem to get just the wing from protoform.
Matt at Hotdog Customs may make one. I bought his C8 Felony and it had an all carbon fiber wing. Vendor section. I own the delta and protform C8. Delta fyi is garbage but I think the wing you can buy separate and am confident it will work. I can double check tomorrow?
 
Matt at Hotdog Customs may make one. I bought his C8 Felony and it had an all carbon fiber wing. Vendor section. I own the delta and protform C8. Delta fyi is garbage but I think the wing you can buy separate and am confident it will work. I can double check tomorrow?
Thanks for the heads up!
 
I would ditch the springs and perches all together. You can get the 1/8” fuel tube in the plumbing section at Home Depot. It’s a few bucks for a lifetime supply. Cut them exactly the same left and right. Compare them when fully assembled and ensure they are exactly the same length when done. Adjust if necessary. Also pay attention to how fast you pull full trigger if manually doing so. That last 10% is tempting to rush, but it will induce a wheelie, no doubt. I use the NB4 CH Speed feature, but the Perfect Pass will net you similar results.
 
Most has already been said.
No mater how you achieve it, fuel tube/zipties/other creative solutions, the rear should never be able to get lower than the front, even when the rear is squat down and the front isn't.
If you make sure of that, the spoiler (good or bad) will not make it flip, nor will a full pull trigger (it will only lose grip)


I am running the PF C8 body too. I printed my own 'stiffer' spoiler and i have it reinforced with epoxy/fiberglas, especially in the front. Even if it doesn't gape, it does flex too much:
1632909755967.png

Then again, running spectrum esc/motor i don't think you are running speeds where it's a necessity to reinforce the body.
 
I had no gap from the body to the lip but I am now thinking the rear shocks were too soft. I tried to make another pass with the wing cut down where it broke but it was uncontrollable. Do you think with a stiffer rear and skirts I can avoid this in the future?
I personally have not seen skirts make much if any difference. I'd focus on the suspension and stiffening the body.
I don't think anyone mentioned it yet, but GRPs are a much better tire and grip way better. Get some GRP GTJ 01 tires and make sure to balance them!

As Rot mentioned above the factory ESC will choke in the 90+ mph range from amp limiting. I'd be shocked if it did more than 96 mph.
 
I personally have not seen skirts make much if any difference. I'd focus on the suspension and stiffening the body.
I don't think anyone mentioned it yet, but GRPs are a much better tire and grip way better. Get some GRP GTJ 01 tires and make sure to balance them!

As Rot mentioned above the factory ESC will choke in the 90+ mph range from amp limiting. I'd be shocked if it did more than 96 mph.
Skirts will reduce air entering the body and can support the side of the body. More surface for the ground effect isnt bad either.

Swapping tires on the felony does create yet another problem. Diffs need to be the same to run same size tires front and rear. And the C8 body is wider on the rear, i am currently running wheelhub extenders to compensate for the width.
As long as you use the factory esc, i would stick to the hoons setup. Balancing those is obviously important too.
 
Skirts will reduce air entering the body and can support the side of the body. More surface for the ground effect isnt bad either.

Swapping tires on the felony does create yet another problem. Diffs need to be the same to run same size tires front and rear. And the C8 body is wider on the rear, i am currently running wheelhub extenders to compensate for the width.
As long as you use the factory esc, i would stick to the hoons setup. Balancing those is obviously important too.
I plan on upgrading the electronics pretty soon, just making sure I can get a few sets of bananas before I do.
 
As most have said, more rake than you think you need, and limit rear shock travel. Were you using GT side skirts, I don't see any in the picture, just the stock limitless body setup.. To run a wider GT body you should use the larger side skirts, otherwise its potentially parachute time for the body.. Also, personally I would use a car with the same diffs front and rear for a speedrun car, I believe the different sizes and different wheel rotational speeds may cause some type of instability at high speeds that a car with both diffs and tire sizes being the same wouldn't have. Now, obviously many 1/1 cars have staggered wheel sizes and run extremely fast with no issues, but they also have a lot more engineering in them than our RC cars have. I'm curious to know how fast a Felony with stock diffs and center diff has gotten up to actually
 
As most have said, more rake than you think you need, and limit rear shock travel. Were you using GT side skirts, I don't see any in the picture, just the stock limitless body setup.. To run a wider GT body you should use the larger side skirts, otherwise its potentially parachute time for the body.. Also, personally I would use a car with the same diffs front and rear for a speedrun car, I believe the different sizes and different wheel rotational speeds may cause some type of instability at high speeds that a car with both diffs and tire sizes being the same wouldn't have. Now, obviously many 1/1 cars have staggered wheel sizes and run extremely fast with no issues, but they also have a lot more engineering in them than our RC cars have. I'm curious to know how fast a Felony with stock diffs and center diff has gotten up to actually
I just bought a Felony and I've gotten it up to 115kmh (71.45mph) with 2 HOOVO 6500mAh 120C batteries and the stock gearing and electronics. I raised the suspension to be 8mm from the shock to the tension ring because the street I run it on is a little uneven. This was with the rear wing installed.

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