Ye Olde Rocket Forum - SEMROC Hollow Tubing Couplers

#21

08-24-2006, 08:36 PM

Green Dragon Green Dragon is offline

AL Swackhammer , power freak

Join Date: Sep 2005

Location: New York

Posts: 1,255

Quote:

Originally Posted by snaquin

I'm almost finished with the rocket below and I'll be posting a thread on it soon. It is near minimum diameter Semroc LT-125 and you can see 1/2" of motor tube Semroc LT-115 extended from the rear to tape the 29mm motor to.

That looks suspiciously like a Crown LASOR rocket to me :-) .

noting the motor mount tube sticking out - my bro always left the 29mm mount hang out the back of the LASOR 134's, but filled it as a 'mini-boatail', not as a 'tape over top ' retainer (still could tape over the boatail, but ruins the aerodynamic plus, I bet, lol )

~ AL

Last edited by Ltvscout : 08-24-2006 at 09:02 PM.

#22

08-24-2006, 10:33 PM

Tau Zero

Incurable SEMROC Fan

Join Date: Mar 2005

Location: Twin Falls, Idaho, USA

Posts: 2,319

So many Tau Zeroes, so little time (travel)

Quote:

Originally Posted by CPMcGraw

I just ran a quick sim of the TZ with the fins and ring components shifted forward 0.25". The performance doesn't seem to be hurt, and in fact is improved with every motor when compared to the version with the hook and sleeve.

I wonder if that extra 1/4" helps smooth out the airflow, a little bit like a boattail. Hmm...

Quote:

This might have to become Prototype IV...

Hmm. Although shoving the fins forward *and* using a hook and sleeve...

Craig, buddy, you make my head hurt.

Although *your* Prototype V could be *my* Prototype II...

I'll have to mess with the RockSim file some more.

Cheers,

__________________
Jay Goemmer
"Centuri Guy"/"Tau Zero"
YORF Member 28
Semroc SAM #0029
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"I think about organizing things all the time. Never seems to happen. I find something that piques my interest and I'm off on a quest. Or a Centuri.

"

--Bill Eichelberger, 02/22/2022

“Centuri fret buzz in an updated form.”
Bill “Wallyum” Eichelberger re: Estes Flutter-By
03 Sept 2014

#23

08-24-2006, 10:38 PM

Tau Zero

Incurable SEMROC Fan

Join Date: Mar 2005

Location: Twin Falls, Idaho, USA

Posts: 2,319

"Slightly bigger" HTC-7B's

Quote:

Originally Posted by Carl@Semroc

The ordered dimensions are:

HTC-7B - .761 ID X .801 OD X .020 Wall 1.000" Long Fishpaper

but we have one "bad" lot that is slightly bigger that we did not throw away that has a little more play for an engine hook. We use it for the pop-pod on the Swift-BG (unreleased).

Hmm... What are the (ballpark) measurements for those "slightly bigger" couplers? Those would be a lot easier to slip over an ST-7 with an engine hook in it.

Curious,

"

--Bill Eichelberger, 02/22/2022

“Centuri fret buzz in an updated form.”
Bill “Wallyum” Eichelberger re: Estes Flutter-By
03 Sept 2014

#24

08-25-2006, 01:44 AM

Carl@Semroc Carl@Semroc is offline

Junior ??? Rocketeer

Join Date: Mar 2005

Location: Knightdale, NC

Posts: 1,470

Quote:

Originally Posted by CenturiGuy

Hmm... What are the (ballpark) measurements for those "slightly bigger" couplers? Those would be a lot easier to slip over an ST-7 with an engine hook in it.

Curious,

They appear to be about .003" oversize. Measuring tubes is an art that I have never mastered. I can get about any result I want (or don't want.)

I need to send you some to play with. What is the final length of the ST-7?

__________________
Carl McLawhorn
NAR#4717 L2
semroc.com

#25

08-25-2006, 09:22 PM

snaquin

The_Ripper

Join Date: Jun 2005

Location: Louisiana

Posts: 1,941

Quote:

Originally Posted by Green Dragon

AL,

Lasor 134 thread coming to a forum near you - soon .....

That mini-boatail is a pretty cool idea too!

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Steve Naquin
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#26

08-25-2006, 10:12 PM

Tau Zero

Incurable SEMROC Fan

Join Date: Mar 2005

Location: Twin Falls, Idaho, USA

Posts: 2,319

Those devilish (?) details...

Quote:

Originally Posted by Carl@Semroc

They appear to be about .003" oversize. Measuring tubes is an art that I have never mastered. I can get about any result I want (or don't want.)

I need to send you some to play with.

I'll contact you off-forum about that.

Quote:

What is the final length of the ST-7?

I think Craig is lobbying for 10". I wanted to keep it at your standard 9", but Craig has this cool idea about shoving all of the fins forward 1/4", which also messes with the stability a little bit, and *then* you factor in the added rearward weight of the the coupler and engine hook... ("worn out" emoticon)

Like I told Craig, I need to mess with the RockSim file some more. Once I decide, I'll let you know.

Thanks again, as always,

"

--Bill Eichelberger, 02/22/2022

“Centuri fret buzz in an updated form.”
Bill “Wallyum” Eichelberger re: Estes Flutter-By
03 Sept 2014

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