Stabilizing the descent?

[blike]

Recently I launched my second rocket with an onboard camera. It was my first mid-power kit (an AT Initiator). I flew it on a G40 and boy did it fly. Unfortunately, the camera lost power on impact with the ground, and thus, I lost all the onboard footage.

Anyhow, I noticed that the rocket was in an extreme spin under the parachute during descent. The nose cone (which had extra weight because of the camera) was spinning rapidly around the vertical axis under the parachute. For my next video rocket, I want nice view of the descent rather than out of control spinning that I've had in the past with all rockets the camera has flown on. Is it possible to stop the rotation of the body tube during descent? How can this be accomplished?

 

[lalligood]

2 ideas that should help:

1) Hook your parachute up to the shock cord with a swivel. That will allow the chute to spin freely of the rocket without causing the rest of the rocket to want to spin..

2) Change up the connection order of your recovery system. Instead of rocket <-> chute<-> NC (where '<->' indicates the shock cord), make it rocket <-> NC <-> chute.

HTH,

 

[GL-P]

1) Make sure there is a drift hole in your chute. Should help to balance it

2) Make sure the shroudlines are balanced

3) Cable tie the battery to the connectors

 

[Missileman]

Along with the excellent suggestions above chute style may be considered.
Hemispherical chutes spin less than flat ones.

 

[DynaSoar]

Originally posted by missileman
Along with the excellent suggestions above chute style may be considered.
Hemispherical chutes spin less than flat ones.

Agreed. Anchor has some nice ones.

A swivel will help some. To make it work better, lube it. If you don't have some powdered graphite "lock lube", some 3 in 1 oil or WD40 would help. You can put two of these in a row also.

Don't tie the shroud lines to the swivel. Let them slide through it loosely. That way they can't become unbalanced (different lengths). If you need a connector that allows this, going through the shrouds and the swivel, get a "quick connector". It looks like a single chain link with a threaded piece on one side that allows opening and closing.

 

[Stymye]

Is it possible to stop the rotation of the body tube during descent? How can this be accomplished?

A Bridle recovery setup works like a champ
because your connection lines come from 2 points on the body tube

 

[BobH48]

stymye,

Great tip about the bridle recovery. I never would have thought of that.

 

[eugenefl]

Originally posted by blike
Recently I launched my second rocket with an onboard camera. It was my first mid-power kit (an AT Initiator). I flew it on a G40 and boy did it fly. Unfortunately, the camera lost power on impact with the ground, and thus, I lost all the onboard footage.

Anyhow, I noticed that the rocket was in an extreme spin under the parachute during descent. The nose cone (which had extra weight because of the camera) was spinning rapidly around the vertical axis under the parachute. For my next video rocket, I want nice view of the descent rather than out of control spinning that I've had in the past with all rockets the camera has flown on. Is it possible to stop the rotation of the body tube during descent? How can this be accomplished?

blike, At one time I was an avid onboard video and camera rocketeer. After 2 camera losses (tree and alligator infested lake) I kinda called it quits.

The absolute *best* way that I have found to control/eliminate spin is to use dual chutes. That's right - two. Once I switched to two chutes I *never* saw the camera pod spin again and thus got much better results when I dropped off the film for development. Check out my outdated website for my onboard camera shots. <a href="https://home1.gte.net/res0xphr/index.html">EMC Rocketry</a>. I use the "Ray Dunakin" camera pod for my onboard pics. The chutes are connected to the top of the payload section. The chutes in turn inflate and "pull" away from the pod in opposite directions thus reducing the ability of the shockcords to spin around themselves. For usage, replace a 24" with dual 14"-16" chutes.

Lance, although the swivel idea seems sound, unfortunately the payload tends to spin freely while the chute remained still. The chute has a lot of drag while the pod has no forces acting on it.

 

[eugenefl]

Although I never really got any good recovery shots, in this "X-Files" type picture you can barely see the chutes pulling outward. The recovery phase is much more enjoyable this way too!

In my attempts to capture onboard footage, I've lost (2) AT 22" chutes, (2) AT 16" chutes, (1) LOC 18" chute, one Kodak Advantix camera, one Intel DMC digital camera. They have all been tough losses. I have yet to overcome them. I think Jason (jetra2) hit the nail on the head - the only way to cure my losses is to build another and try again.

 

[eugenefl]

Here's the vehicle and payload. It's a LOC Graduator and Ray Dunakin styled camera pod nosecone-payload.

 

[eugenefl]

Attached is a picture of the rocket and payload boosting on a G40-7W. This was one of the best liftoff shots I've ever captured.

 

[havoc821]

That is a cool picture!

 

[Rubr_Duky]

Go to your local toy store, and get one of those little gyroscopes, and mount it in your nose cone. Attach a swivel to your nose cone, and get a longer string for your gyroscope. Mount everything on the pad, and just before you run away, give that gyroscope a HUGE pull, and run. launch your rocket, and by the time it begins to descend, it should still be spinning just enough to keep your camera steady.

Not proven, but it's just a thought/


RD

 

[Jerry Irvine]

1. Bridle
2. Large spill hole in parachute
3. Crossform parachute

Jerry

 

[JRThro]

Originally posted by lalligood
2 ideas that should help:

1) Hook your parachute up to the shock cord with a swivel. That will allow the chute to spin freely of the rocket without causing the rest of the rocket to want to spin..

2) Change up the connection order of your recovery system. Instead of rocket <-> chute<-> NC (where '<->' indicates the shock cord), make it rocket <-> NC <-> chute.

HTH,

I generally do both of these, by tying the shock cord to the nose cone, and then attaching the parachute to the nose cone with a snap swivel. I have no idea if it reduces spin while descending, but it makes it easy to swap out chutes if I need to. Also, I'm thinking that this method pretty much ensures that the parachute *will* deploy if the nose cone pops off.