Record for Black Powder Gap Staging? 51 inches?

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DoubleOrNothing2 (the first DoubleOrNothing was only 33 inches total gap)

Successful Launch and Recovery of both Cluster Booster and Single Engine Sustainer at Club launch Mid South Rocket Society Saturday June 9, 2018

Booster launched on primary D12-0 with an A8-3 in a pod (deploys the parachute)

Sustainer single engine A8-3.

Other than a singed streamer, no damage.

Total Gap distance between forward end of the D12 in booster and the tail end of the A8 in sustainer: 51 inches.

Does anybody know of any successful black powder gap staging of greater distance?

Thanks,DoubleOrNothing2Stack2.jpg

Tom
 
I'm impressed by both of those figures, both being at a much greater distance than I'd have ever guessed would have been possible. Kudos to both of you.
 
Wondering...could the distance be increased even more if a little BP was poured into the booster motor. It might need to be coarser than FFFF as some have suggested that it is particles of burning BP (rather than just hot gases) that land in the upper stage nozzle.

It's not a modification of the motor. BP is poured into all sorts of containers for electronic ignition; this would just be using a different container to insure upper- stage ignition.

Best -- Terry
 
Wondering...could the distance be increased even more if a little BP was poured into the booster motor. It might need to be coarser than FFFF as some have suggested that it is particles of burning BP (rather than just hot gases) that land in the upper stage nozzle.

It's not a modification of the motor. BP is poured into all sorts of containers for electronic ignition; this would just be using a different container to insure upper- stage ignition.

Best -- Terry
I’m kind of a purist, but since this is not to my knowledge an officially sanctioned competition, there really aren’t any rules. At the point you start messing with extra powder, you might as well just put a quick burning fuse between the two motors, at which point the distance issue becomes more of a SuperRoc contest (you can Gap just about any distance if you have enough starting velocity at staging and a fast enough burning fuse.)

So far I have limited myself to D motors, supplemented with an A for the chute deployment pod. I am not sure the F15-0 is still available, likely could successfully fill a pretty long tube with gas hot enough to light a sustainer.
 
Wondering...could the distance be increased even more if a little BP was poured into the booster motor. It might need to be coarser than FFFF as some have suggested that it is particles of burning BP (rather than just hot gases) that land in the upper stage nozzle.

It's not a modification of the motor. BP is poured into all sorts of containers for electronic ignition; this would just be using a different container to insure upper- stage ignition.
I would guess something like 80% FFg with about 20% FFFFg for packing density. Surely someone has done this study in a firearms or pyro publication....
 
Wondering...could the distance be increased even more if a little BP was poured into the booster motor. It might need to be coarser than FFFF as some have suggested that it is particles of burning BP (rather than just hot gases) that land in the upper stage nozzle.

It's not a modification of the motor. BP is poured into all sorts of containers for electronic ignition; this would just be using a different container to insure upper- stage ignition.

Best -- Terry


Run a length of "Black Match" between the motors . . . Distance is no longer a problem - LOL !

Dave F.
 
For probably the first five or six years that I flew HP with electronics, I used 3F bp for all my ejection charges without any failures. Finding 2F bp might be a bit harder, but 3F is widely available. So if I was going to try a gap-stage ignition, I'd probably use 3F.

On the thread itself..... 51 inches? Was that without any added BP, just the motor "ejection charge? That's incredible!

Brad
 
For probably the first five or six years that I flew HP with electronics, I used 3F bp for all my ejection charges without any failures. Finding 2F bp might be a bit harder, but 3F is widely available. So if I was going to try a gap-stage ignition, I'd probably use 3F.

On the thread itself..... 51 inches? Was that without any added BP, just the motor "ejection charge? That's incredible!

Brad
Just motor plain old zero delay black powder Estes motor. D12-0. I have done 72” on a test stand the same way.

Too bad I can’t find any F15-Os! 😈
 
QUESTION :

What is the "reliability" and "repeatability" of gap-staging at these extended distances.

As distance increases, those factors must, necessarily, decrease.

Dave F.
 
At 36" and 48" I have had 100%

At 72" 0% in flight (1 attempt)

At 51 " 66%, (2/3) and not sure I would count the failure. The boosters are clusters.
The main on the booster didn't ignite. the Auxiliary for booster chute deployment (an A8-3!) did. It barely got off the rail and returned to the ground. 307017-4242f7d2c05429da786def0bd71c785b-1.jpg

That said, I tend to use large nozzle sustainer motors (A8-5 or D12-7) as I think the larger nozzle increases "lightabilty ".

48" with a D to D or D to A is a snap.
 
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At 36" and 48" I have had 100%

At 72" 0% in flight (1 attempt)

At 51 " 66%, (2/3) and not sure I would count the failure. The boosters are clusters.
The main on the booster didn't ignite. the Auxiliary for booster chute deployment (an A8-3!) did. It barely got off the rail and returned to the ground.

That said, I tend to use large nozzle sustainer motors (A8-5 or D12-7) as I think the larger nozzle increases "lightabilty ".

48" with a D to D or D to A is a snap.

Agreed on the larger Nozzles . . . The OOP Estes B14 would have been ideal !

Are the rockets being used all minimum-diameter ?

Do you have any pics of the setup and flights ?

Thanks,

Dave F.

1968 B14 THRUST CURVE.jpgB14 DATA.png
 
Was the Test Stand horizontal or vertical ?

Dave F.
Horizontal.

Some examples of long gaps

https://www.rocketryforum.com/threa...-horizontal-spin-booster.149667/#post-1856679
https://www.rocketryforum.com/threads/successful-launch-and-staging-cerberus-iii.46235/#post-1724867

https://www.rocketryforum.com/threa...p-between-motors-partially-successful.145480/
https://www.rocketryforum.com/threads/perfect-24-gap-staging-see-last-post.45863/#post-442964
https://www.rocketryforum.com/threa...hin-36-gap-staged-2-successful-flights.47731/
Biggest challenge is NOT with getting sustainer to ignite. Just put the vents just below the sustainer motor.

Two much more difficult challenges for black powder long stage or large booster operation.

1. Booster recovery. Once you get much beyond, say 6” gap for LPR or MPR (I guess if you cluster enough black power motors you could run into HPR territory as well), the booster is likely to remain stable and/or be too heavy for tumble recovery. My solutions have been to cluster with an auxiliary short delay motor that deploys a chute a few seconds AFTER staging. I learned you do NOT want to deploy a chute immediately after staging because the booster is still hauling butt and will shred your chute, so a three second delay works well). Other option is horizontal spin recovery. I need to try a streamer.

2. These are tall rockets. Ideally the sustainer should be on the rail, if not you need some extra support while on the pad to keep the sustainer on the booster.
 
I've recovered the booster with dual streamers. There are pods housing the streamers attached to the sides at the aft end of the sustainer. The booster has matching plugs at the forward end where the streamers are actually attached, and seal the bottom of the pods when the booster and sustainer are put together for launch. Of course, these are deployed immediately when separation occurs, but since it's streamers, it hasn't messed anything up so far.
 
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