Problems with 2 stage renegade flights

SammyH

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Hi, i was wondering if anyone could help me out with flying a 2 stage estes renegade, whenever i fly it something goes wrong, it flies perfectly on a single stage, ive already broken the little pods on the end of the fins off, and torn the body tubing when the nosecone failed to eject. On the 1st 2 stage flight, the 2nd stage motor ignited too early, and decided to send the booster back to earth, still burning away, it got stuck 2-3 cm int the ground and the pod had snapped off. on the second 2 stage flight the booster went off fine, but when the second stage ignited it popped out the rocket, and the rocket kinda like plummeted to the ground, any help would be appreciated.

Thanks
Sam
 

graylensman

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Um... The second stage ignition with first stage still burning is a new one on me- seems like a motor failure would be the only explanation there. A failure to eject the nose usually indicates your chute was packed in too tight, or the nose cone shoulder is tight as well. As to the other problems, at first blush I'd say there were some poor construction techniques involved.
 

powderburner

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Hi SammyH,

Do you remember if you taped the motors together on your two-stage flights? Did you use a couple wraps of cellophane tape?

The early booster separation (both booster and upper stage motors burning at the same time) is a new one on me too. I am not sure at all what happened there, unless maybe you had a bad booster motor where the propellant grain had separated from the case (that would create a path for the hot gasses to bypass the propellant and go directly to the upper motor?).

I think that if you will 'search' the forum for Renegade posts, you will find lots of people have been complaining about that particular booster getting a lot of damage. Normally you design booster stages to tumble, but the Renegade seems to want to dive straight in. My first one did the same. I had to add 'non-scale' fins to the front end of the second one to get the booster to tumble, and it still hit hard.

Is this your first two-stage rocket? There are others that are easier and faster to build, and would give you some better experience with multi-staging. The Renegade seems to have some quirks?
 

jflis

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Welcome to TRF, sammy :)

Another common concern that I've seen with multi-stage rockets (easy to miss if you aren't familiar with them) is the use of a standard motor in the lower (booster) stage.

The effect is that the motor burns, then the delay charge, then the ejection charge ignites the upper stage and pushes the stages apart. Visually, you seel the booster drop off still smoking considerably from the delay charge burning and it can look like the motor is still burning.

Check to make sure that you used a proper booster motor (one with a delay of "0", like B6-0)

Other than that, this truely is an odd one. WOuld you have pictures of both stages that we could look at? Close ups of both motor mounts may show us something that we hadn't considered.

jim
 
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