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I would think the spring launcher would be best . Right now Im trying to understand how I should make it .

Does the pic make sense . Would that work ?
I would throw a gusset in there too, I posted this in another thread, my friend had maybe a 4" or so so drop from the attachment point and ripped it all off. He was also pushing the car at the same point, that may have contributed, IMG_20191019_182108867.jpg
 

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It will be fine, but it's still pulling from the low point where the hitch meets the frame. Just because you cheat it up the pipe doesn't mean you change the point that it exerts force on the chassis, you just put extra load on that bend or joint where it curves up.


But you're not going to lift or effect the rear of the truck being that heavy, really put it anywhere and it will be fine.
 

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I would think the spring launcher would be best . Right now Im trying to understand how I should make it .

Does the pic make sense . Would that work ?
Pic makes sense but it won't work ------ as drawn, the lanyards are still connected to the hitch, which is well below the height of the cam centerline. In that location, the chute is going to want to pick up the rear of the truck. Not good.
 

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Stroud says crankshaft or cam , center of mass .

Not sure how to take that . lol
Even if you were to split the difference between the crank and cam centerlines, the attachment point of the lanyards is still going to higher than the height of the hitch.

Not sure what they mean by "center of mass". Center of gravity typically falls near the camshaft centerline.
 

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Pic makes sense but it won't work ------ as drawn, the lanyards are still connected to the hitch, which is well below the height of the cam centerline. In that location, the chute is going to want to pick up the rear of the truck. Not good.
It will work fine at the hitch. It will not pull the ass of that truck up, no way, no how.
 

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I kill parts
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It will be fine, but it's still pulling from the low point where the hitch meets the frame. Just because you cheat it up the pipe doesn't mean you change the point that it exerts force on the chassis, you just put extra load on that bend or joint where it curves up.


But you're not going to lift or effect the rear of the truck being that heavy, really put it anywhere and it will be fine.
Yes it would still be pulling on the hitch(which is fine) but it would be pulling closer to his CG height.



There definitely is good thought to the total weight of his truck and speed, making it less necessary for ideal attachment height. - A good quality 4-6" drop hitch flipped up would probably make for a great attachment point and easy to remove. Could just use a clevis from the straps through the hole for the ball.
 

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Discussion Starter #29
I think I'll build an air launch setup . I already have an air cylinder .

I was looking at this Chute , but it doesnt specify if it is a pilot chute setup or if its just the chute .

Anyone know anything about this ?

 

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Discussion Starter #35
LOL ....... heres the actual part links .

The chute mount is from DeVito Racing Compound . ( Facebook )





 

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Another quick question .

Will this 4340 .50" dia pin be adequate for the tether loop ?

Allstar Performance Quick-Release Pins ALL60318
Single shear stress could be around 35ksi using stroud’s “up to 1.5g” deceleration, so 1.5 times the weight of your brick. In double shear, the stress from the chute pull would be 1/2 of that.
The bearing area of the pin will see the most wear. The amount of wear will be related to the “fit” between the receiver/hitch and the pin. Looser fit means higher bearing stresses.
The description of the pin is “4130” which doesn’t automatically make it awesome. Look up hot rolled 4130 bar stock mat props snd see if its yield strength is at least 3 times the double shear stress and you’ll be good for a while.
 
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