What could I do to stop the parachuting effect? Traxxas slash with stock body

[DavidB1126]

I noticed with the new tires, they have so much traction it wheelies and then catches air underneath the body and parachutes. What could I do to stop that effect? I was running the stock traxxas body (well the clear one I painted up) also tested my PL slilverado body and still did the same parachuting effect. Maybe try to add more weight up front? If a yes for weight I can zip tie one of my flashlights to the front bumper. I had seen people use amazon beetle bodies or the PL bug body to stop it. But I do want to keep the short course style body. Proline makes I think its called a flo tek body where they have cut outs in the rear and front to control the air going through.
PL Flo-Tek SCT body Precut

 

[ahr43]

Hey, DavidB. Post up a picture of the slash in running attitude if you have one. That will help us help you. What surface are you running on? Multi-surface or dedicated surface?

Are you running a rear spoiler? Cutting it down or eliminating it entirely may help. Adding weight to the front is always an option. Are there any ways you can help prevent air from getting under the body? Does the body fit close enough to the chassis side rails to attach velcro strips to the inside of the body? Venting the body is an option as well. If you are racing the slash, check the track rules before venting.

Adding more rake to the front could help. e.g., lower ride height front than rear so it sits nose down. Oh, you running a wheelie bar? Set it lowest you can. Fabricating a front air dam to block and deflect air from going under the body is a consideration.

[ EDIT: adding an image of Rustler front air dam paper mock-up. Front weight bar also visible. ]

Hope this helps a bit. Sure others will have suggestions as well. Cheers. 'AC'

 

[DavidB1126]

I am leaning towards the flotek body since I need a new one and a stronger one too. Also planning to get some new colors too. Thinking about a darker blue and some purple. And a little spray of silver or orange in there. The traxxas clear one is all cracked up and scratched up.

Hey, DavidB. Post up a picture of the slash in running attitude if you have one. That will help us help you. What surface are you running on? Multi-surface or dedicated surface?

Are you running a rear spoiler? Cutting it down or eliminating it entirely may help. Adding weight to the front is always an option. Are there any ways you can help prevent air from getting under the body? Does the body fit close enough to the chassis side rails to attach velcro strips to the inside of the body? Venting the body is an option as well. If you are racing the slash, check the track rules before venting.

Adding more rake to the front could help. e.g., lower ride height front than rear so it sits nose down. Oh, you running a wheelie bar? Set it lowest you can.

Hope this helps a bit. Sure others will have suggestions as well. Cheers. 'AC'

Planning on taking a video this weekend. Multi-surface (only parachutes when on the sidewalk or road,not off road) (I'm running off road in grass, and then on road on the sidewalk and road) I'm not running any spoiler. I do have the body mounts a little bit higher because of my wider anaconda tires but I can always lower it. (I have the stock adjustable body mounts in the rear and the PL locking caps on the front, both are adjustable) I can also remove some of the preload spacers on the shocks to lower it. I think I am current running the shocks on the second hole in the arm closest to the wheel. And in the rear I am running the second hole closest to the wheel (on the lower suspension arms) I do have a wheelie bar in my spare parts bin but currently running the RPM rear bumper and RPM bumper mount. Also something to note is right now I am running 50wt AE oil in the front and rear shocks. I do got a spare velcro pack from my buggy so I can velcro the body to the side nerf bars and still keep the actual body mounts (the clips in the rear and the PL locking caps in the front)

 

[ahr43]

Those are the two surfaces my Rustler runs. On-road and grass. Grass is pretty forgiving if like a baseball outfield or soccer field. You can run pretty close to an on-road set-up on it. Field grass not so much so.

Sounds like you have a plan. Making changes one or at most two at a time until you get the truck where you want it. Tuning the air for speed is a slog. 'AC'

 

[bill_delong]

What are your driving conditions?

Street?
Speed Runs? If so, what speeds?

FloTek will certainly help, but they can only do so much.

In order to mitigate your issues, you can maximize downforce by installing a rear wing or simply do a \BACKSlash conversion:

 

[DavidB1126]

Field grass not so much so.

Yea, I'm driving in the front/back yard which has thick grass. And the field across the street which is a lot more thin grass.

What are your driving conditions?

Street?
Speed Runs? If so, what speeds?

Sidewalk, street, off road in the grass, speed runs. Mostly everything except for like dirt and stuff like that.

For speeds, I thinking any where between 35 and 45 mph with the gearing and set up I have right now.

 

[bill_delong]

FloTek will definitely sustain speed runs of 45mph but your biggest issue is trying to mix-match too many terrain types.

For speed runs, you'll want to decrease your ride height, go with stiffer suspension and loosen the center slipper to prevent wheelies, also consider using expo on the throttle to soften the acceleration curve

Add ride height back for off-road bashing... consider 2 different sets of shocks/wheels when switching between street and off-road.

 

[TRAT]

Drive slower ehhh never mind who am I to say

 

[ahr43]

^^ What Bill says ^^

Additionally, I've found limiting STG end points considerably for speed runs and adjusting STG expo for softer action at beginning of the steering wheel helps. You don't want a lot of quick or full steering action at speed. Normally set my STG end point using the least amount of turn to turn the truck around on a city street, curb-to-curb at slow speed.

45mph (72.4kph) is a good target speed. Just completed on-road speed runs with my Rusty yesterday at 47mph. Faster than it sounds as far as how quickly the truck covers ground.

For an experiment, extend your palm, fingers extended and closed, outside the family car window at 45mph gives you a feel for the wind pressure the car feels. Full adult hand has about the same frontal area as an off-road tired 1/10 ST. Oh, and be careful doing that. Not in a high traffic area of busy street, o.k.?

[ EDIT: regarding throttle punch control. Use as little punch as possible to get the truck up to speed in the distance it is running. Punch coming on has a tendancy to squad the RR of the truck, raising the front allowing it to pick up more air. Rolling on the throttle gently tends to maintain the set chassis attitude. ]

Cheers. 'AC'

 

[tntpoof]

To stop body parachuting drill 1/2" hole in bottom of windshield then cut out fake fans behind rear shock tower been doing this for 10 years never had a body fail

 

[Greywolf74]

I dremeled out some spots that followed certain contours of the body on my high speed Rustler and then glued some screen over the holes using shoe goo. Then I cut the rear lip of the body off. Worked well for me.

 

[Jerold]

If you want to go fast on the road, like 100 MPH or more you have to do some serious mods and you would be better off just buying an Arrma. Even the XO1 takes flight.

There are a few things that help, aerodynamics and the suspension.

For the aero the first I did was to make a "faring" under the body to keep the air out. It attaches in the front under the body mount.

It's just cut from a sheet of Lexan and tucks under the body.

The second and more important thing, swapped the body. I did some venting on the original and it did help but you really have to cut the crap out of it to be effective. So a buddy had an old crawler body that I threw on there and it stays pretty good now. It's got a bit more of a monster truck vibe.

You could add an air dam and splitter to the front too.

If you run it without the body they still go on the lid occasionally. Which means there's a suspension issue. If you are off road, it is what it is. However, if you are street bashing or high speed running, you need to keep the nose down.

I haven't done this on the Slash but it's a must on my speed run car.

1. Better tires. The stock one balloon like crazy and are very unstable on hard surfaces. Swap over to street tire or foams.
2. Stiffen the back shocks. Some people lock them out with turn buckles (I don't like this) or put something on shock shaft to keep it from drooping under hard acceleration. You can use Nitro tubing or I found some grommetts at Lowes that work great.
3. Shorter shocks in the front and back to limit travel and lower the CG and keep the air out from under it.
4. You can add weight to the front as well.

 

[Willy0942]

Hey, DavidB. Post up a picture of the slash in running attitude if you have one. That will help us help you. What surface are you running on? Multi-surface or dedicated surface?

Are you running a rear spoiler? Cutting it down or eliminating it entirely may help. Adding weight to the front is always an option. Are there any ways you can help prevent air from getting under the body? Does the body fit close enough to the chassis side rails to attach velcro strips to the inside of the body? Venting the body is an option as well. If you are racing the slash, check the track rules before venting.

Adding more rake to the front could help. e.g., lower ride height front than rear so it sits nose down. Oh, you running a wheelie bar? Set it lowest you can. Fabricating a front air dam to block and deflect air from going under the body is a consideration.

[ EDIT: adding an image of Rustler front air dam paper mock-up. Front weight bar also visible. ]

Hope this helps a bit. Sure others will have suggestions as well. Cheers. 'AC'

View attachment 159757

These guys got you covered they know what they are talking about.

 

[Tunedfrog]

Make no mistake @Willy0942 , @DavidB1126 is no slouch when it comes to his knowledge. I've learned some from him.

 

[Willy0942]

Make no mistake @Willy0942 , @DavidB1126 is no slouch when it comes to his knowledge. I've learned some from him.

Good to know, maybe I’ll do the same.

 

[WickedFog]

This is an old thread anyway fellers.

 

[Willy0942]

This is an old thread anyway fellers.

Lol, I am new to this stuff forums and all.

 

[WickedFog]

Lol, I am new to this stuff forums and all.

All good

 

[luke66]

honestly, i have not even noticed the parachuting. i have a old slash body i might cut for some racing. who knows.