Cluster and Baffle

[DirkTheDaring]

I'm about to launch a scratch built 2x 29 mm cluster rocket with this baffle and I'm suddenly concerned the output will be too much for it and blow out the body tube. Any thoughts on whether this kind of baffle can handle a couple of F engine ejection charges? BT-80. Thank you.

https://www.erockets.biz/semroc-ejection-baffle-kit-plywood-for-bt-70-sem-eb-70t/

 

[DigBaddy]

If composite motors, you can reduce the charge in both motors or eliminate the charge in one of them (which could be bad if that motor doesn't light).

I'd go with a half-moon style in BT80 if you want both charges to fire on BP motors.That should flow with less restriction.

 

[DirkTheDaring]

If composite motors, you can reduce the charge in both motors or eliminate the charge in one of them (which could be bad if that motor doesn't light).

I'd go with a half-moon style in BT80 if you want both charges to fire on BP motors.That should flow with less restriction.

Thanks, of course it was already built before it occured to me this might be a problem. Estes black powder only (can't squeeze in composite motors as the plastic retention rings won't fit with 2 motors squeezed into a bt80). I'm going to start with 2 D motors in adapters and if that works OK, then I'll move up.

 

[DigBaddy]

Thanks, of course it was already built before it occured to me this might be a problem. Estes black powder only (can't squeeze in composite motors as the plastic retention rings won't fit with 2 motors squeezed into a bt80). I'm going to start with 2 D motors in adapters and if that works OK, then I'll move up.

Two Ds probably will be fine. Could do a D12-0 then one with the proper delay.

 

[Tractionengines]

Just use 2 different delays for BP Motors. If the 1st (with correct delay) pushes it out the 2nd (with longer delay) just goes thru a empty tube. If the 1st didn't get it out completely, you have a backup...

DON'T use a -0 that will try to push it out right away, unless you plug it, but that's not allowed per code, as its a modified motor if you put a epoxy plug over the -0 motor.

 

[Back_at_it]

I'm about to launch a scratch built 2x 29 mm cluster rocket with this baffle and I'm suddenly concerned the output will be too much for it and blow out the body tube. Any thoughts on whether this kind of baffle can handle a couple of F engine ejection charges? BT-80. Thank you.

https://www.erockets.biz/semroc-ejection-baffle-kit-plywood-for-bt-70-sem-eb-70t/

If the baffle was properly built meaning that you used quality wood glue and did fillets then the baffle will be just fine. While this style is not my favorite, I have used it on a few builds and it survives ejections from composites with added powder flight after flight. I have this style in my Der Big Red Max and it has flown on F67's with added powder several times without any issues.

If you are still concerned then you could use staggered ejections. Maybe use a 4 sec. delay and a 6 sec delay. Honestly I don't think you'll have any issues.

 

[DirkTheDaring]

If the baffle was properly built meaning that you used quality wood glue and did fillets then the baffle will be just fine. While this style is not my favorite, I have used it on a few builds and it survives ejections from composites with added powder flight after flight. I have this style in my Der Big Red Max and it has flown on F67's with added powder several times without any issues.

If you are still concerned then you could use staggered ejections. Maybe use a 4 sec. delay and a 6 sec delay. Honestly I don't think you'll have any issues.

Thank you all! And in the end it all worked perfectly. First on a pair of D12s and then a pair of E12s. Unfortunately it now awaits rescue from a rocket-eating tree, but I did get the altimeter back which shows 1424 feet on the E12s. Videos to come.

 

[DirkTheDaring]

Thank you all! And in the end it all worked perfectly. First on a pair of D12s and then a pair of E12s. Unfortunately it now awaits rescue from a rocket-eating tree, but I did get the altimeter back which shows 1424 feet on the E12s. Videos to come.

Three videos of the Fugly Duckling:
- First flight, two D12-3
Second Flight two E12-4
Second flight, viewed from the bottom in slo mo.