Carl, how do you plan to make the core burners?

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Quando Omni Flunkus Moritati

18mm and under will be drilled in post production by another separate machine completely automated. The larger ones... we will cross that bridge then.

The largest core burner initially will be the 3/4C19 - 7.5ns. That was the only booster I liked better than the B14.

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Carl McLawhorn
NAR#4717 L2
semroc.com

Carl;

Given the process in front of you, about how far away is Semroc from putting the first few on a store shelf somewhere?

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John
YORF #003
SAM #004

Hello Carl,

Do you plan to manufacture your own igniter to ship with these? It would seem the 29mm PB would need a special igniter.

The 24mm and 29mm would be exciting for two stage rockets based on the LT tubing sizes. The first thing I think of when I see these 24mm and 29mm BP motors in your diagram is staging them.

.

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Steve Naquin
TRA# 677 L2
NAR# 85518 L2
SAM# 0052

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There are too many variables to solve THAT equation!

Seriously, you are involved in the earliest stages and will probably see the whole thing evolve, warts and all.

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Carl McLawhorn
NAR#4717 L2
semroc.com

We have been working on an igniter for the small engines. The larger engines might need a different design.

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Carl McLawhorn
NAR#4717 L2
semroc.com

Carl,

Concerning those PB (Port Burner, or cored) motors, you said they would need to be drilled. What is the manufacturing problem about using, say, a Teflon-coated mandrel run up through the nozzle during the pressing operation? Couldn't the BP be pressed around the mandrel evenly and completely in a single pass of the ram? Or even have a double-piston, one pressing down from the top, the other pressing the mandrel up from the bottom, to ensure the even distribution of powder?

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Craig McGraw

BARCLONE Rocketry -- http://barclone.rocketshoppe.com
BARCLONE Blogsite -- http://barclone.wordpress.com
BARCLONE Forum -- BARCLONE Forum

BARs helping BARs

SAM 0044
AMA 352635

It's not that easy. You can only pack a small amount of BP at a time. It bonds to the walls. The mandrel fills up and can't be cleaned on-the-fly.

It is really hard to explain.

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Carl McLawhorn
NAR#4717 L2
semroc.com

So the pressing action is multi-layered? You fill a small amount, press it, fill some more, press that, etc... until you build up the final amount of powder, then perhaps, you give the whole mass one final pressing to reach the desired compression density?

That explains why the mandrel approach would be difficult. You would also need a mandrel at each fill and press station, and getting the mandrels aligned correctly each time would be difficult. The drilling process can be done in one pass after the cylinder has been filled and final-pressed.

It's a shame the BP couldn't be hard-pressed into pellets separately, then soft-rammed into the cylinder during the final assembly. I know this brings possible deformation and cracking issues into the pellets, leading to grain failures (CATOs).

I'm learning as we go along. This was new information to me. Thanks!

__________________
Craig McGraw

BARCLONE Rocketry -- http://barclone.rocketshoppe.com
BARCLONE Blogsite -- http://barclone.wordpress.com
BARCLONE Forum -- BARCLONE Forum

BARs helping BARs

SAM 0044
AMA 352635

Will one of the objectives be then to actually produce a USA-based FAI acceptable competition motor?

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John
YORF #003
SAM #004