Staging Methods for LPR Rockets...

[smstachwick]

(Yes, my homemade launch controller has two launch buttons that have to both be pressed at the same time to launch the rocket.

I just caught this on a re-read and I instantly thought of this:

 

[mh9162013]

Tim Van Milligan was just writing that he didn't know why they called it an A8 and A10.

I can't speak to the A10, but I do know that the A8 Estes motor designation is due to grandfathering in of older names that were created before the NAR engine number conventions were put into place.

 

[Five]

"Umm..."? What does "Umm..." mean??? Inquiring minds want to know.

Umm, can you post some pictures please?
Thank you.

 

[smstachwick]

I can't speak to the A10, but I do know that the A8 Estes motor designation is due to grandfathering in of older names that were created before the NAR engine number conventions were put into place.

The A10 advertises its improved maximum thrust over the A3. Both are actually closer to an A2.

The analogue to this is the slightly more cored-out short-delay C5-3 to go with the C6 family, but the C5 retains an average thrust rating that’s at least somewhat close to the actual value because it was a carryover from Centuri, I believe. The average thrust values for the C5 and C6 are closer to 4 and 5 Newtons, respectively.

The A8 does indeed derive from the A.8 (0.8 pounds of average thrust) as I stated previously. All of the old catalogs available online corroborate this. The A8 is really more like an A3.

 

[BABAR]

on the first 2-stage flight the booster section got stuck on the sustainer after burn-out (the spent motor dropped free) and got totally roasted by the upper stage motor. !

STOP!

This to me is a design flaw (with all due respect to the Estes designers, who produce some great rockets, with a few exceptions like the Cosmos Mariner and the MIRV.)

With a good design it should be impossible to eject the booster motor without separation. This means a short rear engine block or a motor hook.

If your want to rebuild the booster and fly your old sustainer, rebuild the booster with a either a motor hook OR a body tube that allows you to place a 1/8” engine block (just a 1/8” section of body tube, cut a small slice out, and glue it into the Rear End of the booster tube. Add a fillet or just and extra layer of glue, keep it short both to avoid Krishnic effect and make it easier to install igniters

this solves problem 1, motor ejection.

problem 2 is failure of separation with the booster motor in place, upper motor fires through the booster motor, as you can imagine doesn‘t work well.

if you have cellophane tape nongap staging, use one layer of tape (just enough to hold the motors together, not enough to unintentionally friction fit.)

you do need a SEPARATE piece of tape to friction fit the booster motor into the booster section (not much, just enough so booster tube doesn’t slide off the motor on boost phase due to drag.

and a SEPARATE friction fit for the sustainer (again if going non-gap staging).

My suspicion is this second failure mode is due to the motor to motor tape wrap UNINTENTIONALLY acting as a friction fit that holds the booster in place after upper stage ignition. You may want to put a motor casing slightly into the forward end of booster (the part that overlaps the tape) and “waggling” it to make sure it is a bit loose around the motor to motor tape joint. This is for taped nongap staging ONLY, the taped motors will maintain alignment on boost.

You do NOT want any “waggle” on GAP staging,

If not for the tape, the stages should separate as easily as a low or mid power nose cone for both gap and no gap staging.

 

[Ronz Rocketz]

STOP!

This to me is a design flaw (with all due respect to the Estes designers, who produce some great rockets, with a few exceptions like the Cosmos Mariner and the MIRV.)

With a good design it should be impossible to eject the booster motor without separation. This means a short rear engine block or a motor hook.

If your want to rebuild the booster and fly your old sustainer, rebuild the booster with a either a motor hook OR a body tube that allows you to place a 1/8” engine block (just a 1/8” section of body tube, cut a small slice out, and glue it into the Rear End of the booster tube. Add a fillet or just and extra layer of glue, keep it short both to avoid Krishnic effect and make it easier to install igniters

this solves problem 1, motor ejection.

problem 2 is failure of separation with the booster motor in place, upper motor fires through the booster motor, as you can imagine doesn‘t work well.

if you have cellophane tape nongap staging, use one layer of tape (just enough to hold the motors together, not enough to unintentionally friction fit.)

you do need a SEPARATE piece of tape to friction fit the booster motor into the booster section (not much, just enough so booster tube doesn’t slide off the motor on boost phase due to drag.

and a SEPARATE friction fit for the sustainer (again if going non-gap staging).

My suspicion is this second failure mode is due to the motor to motor tape wrap UNINTENTIONALLY acting as a friction fit that holds the booster in place after upper stage ignition. You may want to put a motor casing slightly into the forward end of booster (the part that overlaps the tape) and “waggling” it to make sure it is a bit loose around the motor to motor tape joint. This is for taped nongap staging ONLY, the taped motors will maintain alignment on boost.

You do NOT want any “waggle” on GAP staging,

If not for the tape, the stages should separate as easily as a low or mid power nose cone for both gap and no gap staging.

That's what happened Saturday with the Sting Ray. Used masking tape instead of cellophane tape for extra friction fit but worked too well.

 

[Ez2cDave]

Centuri "Pass-Port Staging" . . . TIR-123 . . . I never had a staging failure with their system.

Dave F.

 

[Ez2cDave]

The CENTURI BLACK WIDOW had a "gliding" Booster . . .

https://www.spacemodeling.org/jimz/kb-6.htm



Dave F.

 

[majordude]

Okay, he could have just said that and eliminated the confusion, but whatever...

The internet must not me your native language.

Oh, in Internet means that I meant that as a joke.

 

[Gus]

If you are interested in black powder staging you should find this useful.

high-speed video analysis of staging

 

[Cape Byron]

If you are interested in black powder staging you should find this useful.

high-speed video analysis of staging

Good video.

Don't make mistake I did of watching it on a computer with no audio and relying on the transcript. Not even sure what a 'Brick Vicar' is.

 

[Cape Byron]

Good video.

Don't make mistake I did of watching it on a computer with no audio and relying on the transcript. Not even sure what a 'Brick Vicar' is.

View attachment 542093

It got worse. I had to stop.

Sorry for the highjack. Back to the thread...