Got it. I have a left over booster, from when I lost the sustainer. Want me to send it to you to modify and try again?
Boosted Big Bertha
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n3tjm
Papa Elf
That would be great!
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As stated, sustainer fired (confirmed by chute deployment.)
Did booster SEPARATE?
If not, it’s not a vent hole problem, as you suggested it is too tight a fit.
For LOW POWER gap staged (I don’t know anything on high power), when packed for flight, with the rocket vertical nose-up, if you lift the sustainer GENTLY booster maybe should stay on. If you lift it briskly, booster should separate.
The main purpose of whatever coupling system you use for low power (simplest is minimum diameter nesting sustainer in booster tube just above the vent hole(s)•, is NOT to keep the pieces together, it’s to keep their ALIGNMENT congruent. I haven’t seen drag separation in LOW POWER, at least not prior to sustainer ignition.
Failure to separate would also explain why rocket was coming in ballistic when chute deployed, the extra mass and more importantly the sustainer trying to fire THROUGH the booster motor robbed the rocket of effective thrust, making for a low and premature apogee.
Low power stage coupling needs to be very stout (to use @lakeroadster ‘s term) regarding ORIENTATION/ALIGNMENT. It needs to be very LOOSE regarding ATTACHMENT.
You should need to carefully carry the stacked rocket to the pad to keep it from separating, or even assemble the stack ON the pad.
•I use two holes on opposite sides, when I don’t vent out the back. Probable overkill, but theoretically keeps it from “shoving” or tilting rocket due to force of ejected gases on only one side.
Did booster SEPARATE?
If not, it’s not a vent hole problem, as you suggested it is too tight a fit.
For LOW POWER gap staged (I don’t know anything on high power), when packed for flight, with the rocket vertical nose-up, if you lift the sustainer GENTLY booster maybe should stay on. If you lift it briskly, booster should separate.
The main purpose of whatever coupling system you use for low power (simplest is minimum diameter nesting sustainer in booster tube just above the vent hole(s)•, is NOT to keep the pieces together, it’s to keep their ALIGNMENT congruent. I haven’t seen drag separation in LOW POWER, at least not prior to sustainer ignition.
Failure to separate would also explain why rocket was coming in ballistic when chute deployed, the extra mass and more importantly the sustainer trying to fire THROUGH the booster motor robbed the rocket of effective thrust, making for a low and premature apogee.
Low power stage coupling needs to be very stout (to use @lakeroadster ‘s term) regarding ORIENTATION/ALIGNMENT. It needs to be very LOOSE regarding ATTACHMENT.
You should need to carefully carry the stacked rocket to the pad to keep it from separating, or even assemble the stack ON the pad.
•I use two holes on opposite sides, when I don’t vent out the back. Probable overkill, but theoretically keeps it from “shoving” or tilting rocket due to force of ejected gases on only one side.
Watched the video. Saw the second stage ignite but no booster separation.
That red coupler is pretty tight....I think that is why, in a stock Boosted Bertha, it only goes into the sustainer about 1/4 inch. You had much more engagement between the stages.
Maybe with Ken's booster you can make this work properly, because it will be really cool when it does and a nice alternative to those who have been making the first stage of Boosted Berthas with a 24mm motor mount.
@BABAR's advice is consistent with what John Boren at Estes does....and explains why the accessory Booster-55 and Booster-60 are loose-fitting. All three of them benefit from added venting, though, and that improves their reliability in getting the upper stage lit before separation especially when using C11-0s instead of D12-0s in them.
Other than Boosted Bertha I generally fly only small direct-staging models, where the fit can be tighter and still be OK. I have the occasional failure to get the second stage to light (A3s, generally) but have never had separation fail.
That red coupler is pretty tight....I think that is why, in a stock Boosted Bertha, it only goes into the sustainer about 1/4 inch. You had much more engagement between the stages.
Maybe with Ken's booster you can make this work properly, because it will be really cool when it does and a nice alternative to those who have been making the first stage of Boosted Berthas with a 24mm motor mount.
@BABAR's advice is consistent with what John Boren at Estes does....and explains why the accessory Booster-55 and Booster-60 are loose-fitting. All three of them benefit from added venting, though, and that improves their reliability in getting the upper stage lit before separation especially when using C11-0s instead of D12-0s in them.
Other than Boosted Bertha I generally fly only small direct-staging models, where the fit can be tighter and still be OK. I have the occasional failure to get the second stage to light (A3s, generally) but have never had separation fail.
PM me your mailing address. BTW, I burned up a different booster today when I didn’t have the booster engine in tight enough. The booster engine was ejected, the sustainer flew great, but the booster was fried through and through.
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