Puzzling problem with flight path stability

The Rocketry Forum

Help Support The Rocketry Forum:

teepot

Well-Known Member
TRF Supporter
Joined
Dec 8, 2019
Messages
1,850
Reaction score
1,441
Location
Pahrump, Nevada
I've made and flown several split fin rockets. All have flown straight but no whistle. I've been trying to make a rocket whistle for a while.
 

Grog6

Well-Known Member
Joined
Jul 19, 2021
Messages
238
Reaction score
143
Location
Oak Ridge TN
I've used spin stabilization before;One of my 3 stage efforts.
It was really windy that spring, and my neighbor told me it would make weathercocking go away.
"If it doesn't, spin it faster." :)
Dude was a cool old guy that was part of the Manhatten Project WBW.
He also managed to teach me to make NG,NC, and some other cool stuff that ended up with my chemistry set getting traded for an electronics set, lol.
I learned Trig to know how high they went,and derivatives so I could figure out the optimum weight for a given engine /rocket combo.
It's been very helpful in life, lol.
 

Blast it Tom!

Well-Known Dweeb
TRF Supporter
Joined
Dec 30, 2019
Messages
1,357
Reaction score
1,051
Location
Pittsburgh
You talk about non-axisymmetric weight and drag, what about boost gliders? And even my beloved Pigasus, it is clear that both weight and drag are offset from the center axis in the same direction, and if flies accordingly, with a graceful arch. Not a dangerous arch, but not straight up, either. Just sayin'... it can be real, and if there is a weight (or mass...) concentration on one side of a vehicle, it will create a moment with the thrust vector that will tend to turn the rocket off-vertical.
 

billdz

Well-Known Member
Joined
Feb 11, 2017
Messages
1,333
Reaction score
103
One way to help balance your rocket axially is to mount the batteries on the opposite side of the sled from the electronics. Mounting them all on the same side, especially in a lightweight rocket, can cause the rocket to tilt.
Maybe the original builder put a gob of epoxy on the MM then let it dry on one side. Plausible but stupid…
I've launched 4" diameter rockets that flew straight up with a 20 gram keychain camera taped to the outside of the airframe. I'm no expert but it seems a rocket would have to be really light for the course to be affected by an internal battery or a gob of epoxy. I'd fly it a couple of more times before rejecting Steve's "rockets just do some weird things" theory.
 

rklapp

NAR# 109557
TRF Supporter
Joined
May 8, 2020
Messages
2,369
Reaction score
1,817
Location
Oahu, Hawaii
I've launched 4" diameter rockets that flew straight up with a 20 gram keychain camera taped to the outside of the airframe. I'm no expert but it seems a rocket would have to be really light for the course to be affected by an internal battery or a gob of epoxy. I'd fly it a couple of more times before rejecting Steve's "rockets just do some weird things" theory.
Agree. It would have to be a helluva lot of epoxy to screw it up. My keychain fob is 27g and can affect the stability of a LPR. The cube SQ11 is 17g and works well. The Astrocam cam is the lightest.

On second thought, most cams are not near the motor so doesn't take a lot of epoxy to mess up the stability.
 
Last edited:
Top