Two D15 grains makes a ???

David Erbas-White wrote:

Nice information, but anyone using it needs to look carefully at the spacing -- on initial display, it appeared that the first line read '01000-1.077"'; when reformatted to a different font, the space between the "01000-1" and the .077" became readily apparent.
-Kevin

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Kevin Trojanowski wrote:

Anyone willing to try an 18mm case with a 1.077" nozzle is encouraged to discuss the inversion of the space-time continuim that they have encountered... <G>
David Erbas-White
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David Erbas-White wrote:

Yes, that would be rather generous (and appropriate) of them, I do believe.
The question, of course, is what effect that inversion has on a motor's thrust.....
-Kevin
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Jim Yanik wrote:

Hopefully this won't be as messed up as the last attempt.
Designation Nozzle 18/20 D13-4W 01000-1 .077" 18/20 D13-7W 01000-1 .077" 18/20 D13-10W 01000-1 .077" 18/20 D24-4T 01050 .120" D21 18/20 D24-7T 01050 .120"D21 18/20 D24-10T 01050 .120" D21 24/40 D9-4W 01250 .086" E6/E15 24/40 D9-7W 01250 .086" E6/E15 24/40 D15-4T 01300 .104" E15/E28 24/40 D15-7T 01300 .104" E15/E28 24/40 E11-3J 01250 .086" E6/E15 24/40 E18-4W 01300 .104" E15/E28 24/40 E18-7W 01300 .104" E15/E28 24/40 E28-4T 01350 .141" E30/E50 24/40 E28-7T 01350 .141" E30/E50 24/40 F12-3J 01250 .086" E6/E15 24/40 F12-5J 01250 .086" E6/E15 24/40 F24-4W 01300-1 .125" 24/40 F24-7W 01300-1 .125" 24/40 F39-6T 01350-2 .166" 24/40 F39-9T 01350-2 .166" 29/40-120 E16-4W 01250 .086" E6/E15 29/40-120 E16-7W 01250 .086" E6/E15 29/40-120 E23-5T 01300-1 .125" 29/40-120 E23-8T 01300-1 .125" 29/40-120 F22-5J 01300 .104" E15/E28 29/40-120 F22-7J 01300 .104" E15/E28 29/40-120 F40-4W 01300-2 .136" 29/40-120 F40-7W 01300-2 .136" 29/40-120 F40-10W 01300-2 .136" 29/40-120 F52-5T 01350-1 .156" 29/40-120 F52-8T 01350-1 .156" 29/40-120 F52-11T 01350-1 .156" 29/40-120 G33-5J 01300-1 .125" 29/40-120 G33-7J 01300-1 .125" 29/40-120 G64-4W 01350 .141" E30/E50 29/40-120 G64-7W 01350 .141" E30/E50 29/40-120 G64-10W 01350 .141" E30/E50 29/60 F37W-S 01400 .104" F10/F30 29/60 F37W-M 01400 .104" F10/F30 29/60 F37W-L 01400 .104" F10/F30 29/60 F62T-S 01400-2 .125" F10/F30 29/60 F62T-M 01400-2 .125" F10/F30 29/60 F62T-L 01400-2 .125" F10/F30 29/100 G54W-S 01400-3 .136" F10/F30 29/100 G54W-M 01400-3 .136" F10/F30 29/100 G54W-L 01400-3 .136" F10/F30 29/100 G104T-S 01400-3 .136" F10/F30 29/100 G104T-M 01400-3 .136" F10/F30 29/100 G104T-L 01400-3 .136" F10/F30 29/120 G77R-S 01500 .180" F60/G80 29/120 G77R-M 01500 .180" F60/G80 29/120 G79W-S 01450-4 .172" G45/F60 29/120 G79W-M 01450-4 .172" G45/F60 29/120 G79W-L 01450-4 .172" G45/F60 29/180 G75J-S 01450-2 .156" G45/F60 29/180 G75J-M 01450-2 .156" G45/F60 29/180 H128W-S 01500 .180" F60/G80 29/180 H128W-M 01500 .180" F60/G80 29/180 H128W-L 01500 .180" F60/G80 29/180 H165R-S 01500 .180" F60/G80 29/180 H165R-M 01500 .180" F60/G80 29/180 H165R-L 01500 .180" F60/G80 29/180 H238T-S 01500-5 .228" F60/G80 29/180 H238T-M 01500-5 .228" F60/G80 29/180 H238T-L 01500-5 .228" F60/G80 29/240 H97J-S 01450-5 .177" F60/G45 29/240 H97J-M 01450-5 .177" F60/G45 29/240 H180W-S 01500-3 .213" F60/G80 29/240 H180W-M 01500-3 .213" F60/G80 29/240 H180W-L 01500-3 .213" F60/G80 29/240 H210R-M 01500-3 .213" F60/G80 29/240 H210R-L 01500-3 .213" F60/G80 29/240 H220T-S 01500-6 .266" F60/G80 29/240 H220T-M 01500-6 .266" F60/G80 29/240 H220T-L 01500-6 .266" F60/G80 29/360 H268R-M 01550 .291" NEW L2 29/360 H268R-L 01550 .291" NEW L2 29/360 I200W-S 01550 .291" NEW L2 29/360 I200W-M 01550 .291" NEW L2 29/360 I200W-L 01550 .291" NEW L2 38/120 G61W-S 01400-3 .136" F10/F30 38/120 G61W-M 01400-3 .136" F10/F30 38/120 G61W-L 01400-3 .136" F10/F30 38/120 G67R-S 01400-3 .136" F10/F30 38/120 G67R-M 01400-3 .136" F10/F30 38/240 H73J-S 01450 .141" F60/G45 38/240 H73J-M 01450 .141" F60/G45 38/240 H73J-L 01450 .141" F60/G45 38/240 H123W-S 01500 .180" F60/G80 38/240 H123W-M 01500 .180" F60/G80 38/240 H123W-L 01500 .180" F60/G80 38/240 H148R-S 01500 .180" F60/G80 38/240 H148R-M 01500 .180" F60/G80 38/240 H148R-L 01500 .180" F60/G80 38/240 H242T-S 01500-5 .228" F60/G80 38/240 H242T-M 01500-5 .228" F60/G80 38/240 H242T-L 01500-5 .228" F60/G80 38/360 H112J-S 01450-3 .161" F60/G45 38/360 H112J-M 01450-3 .161" F60/G45 38/360 H112J-L 01450-3 .161" F60/G45 38/360 I218R-S 01500-5 .228" F60/G80 38/360 I218R-M 01500-5 .228" F60/G80 38/360 I218R-L 01500-5 .228" F60/G80 38/360 I161W-S 01500-5 .228" F60/G80 38/360 I161W-M 01500-5 .228" F60/G80 38/360 I161W-L 01500-5 .228" F60/G80 38/360 I357T-S 01500-6 .266" F60/G80 38/360 I357T-M 01500-6 .266" F60/G80 38/360 I357T-L 01500-6 .266" F60/G80 38/480 I154J-S 01500 .180" F60/G80 38/480 I154J-M 01500 .180" F60/G80 38/480 I211W-S 01500-6 .266" F60/G80 38/480 I211W-M 01500-6 .266" F60/G80 38/480 I211W-L 01500-6 .266" F60/G80 38/480 I285R-S 01500-6 .266" F60/G80 38/480 I285R-M 01500-6 .266" F60/G80 38/480 I285R-L 01500-6 .266" F60/G80 38/480 I300T-S 01500-7 .313" F60/G80 38/480 I300T-M 01500-7 .313" F60/G80 38/480 I300T-L 01500-7 .313" F60/G80 38/600 I195J-S 01500 .180" F60/G80 38/600 I195J-M 01500 .180" F60/G80 38/600 I195J-L 01500 .180" F60/G80 38/600 I284W-S 01500-6 .266" F60/G80 38/600 I284W-M 01500-6 .266" F60/G80 38/600 I284W-L 01500-6 .266" F60/G80 38/600 I366R-S 01550 .291" NEW L2 38/600 I366R-M 01550 .291" NEW L2 38/600 I366R-L 01550 .291" NEW L2 38/600 I435T-S 01550-1 .313" NEW L2 38/600 I435T-M 01550-1 .313" NEW L2 38/600 I435T-L 01550-1 .313" NEW L2 38/720 I600R-M 01550 .291" NEW L2 38/720 J350W-S 01550 .291" NEW L2 38/720 J350W-M 01550 .291" NEW L2 38/720 J350W-L 01550 .291" NEW L2 38/720 J420R-S 01550 .291" NEW L2 38/720 J420R-M 01550 .291" NEW L2 38/720 J420R-L 01550 .291" NEW L2 38/1080 J570W-S 01550-2 .359" NEW L2 38/1080 J570W-M 01550-2 .359" NEW L2 38/1080 J570W-L 01550-2 .359" NEW L2
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This should be in the FAQ.
--
Jerry Irvine, Box 1242, Claremont, California 91711 USA
Opinion, the whole thing. <mail to: snipped-for-privacy@gte.net>
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(Impakt) writes:

Because the full F doesn't have the seam between the two halves.
    Bob Kaplow    NAR # 18L    TRA # "Impeach the TRA BoD"         >>> To reply, remove the TRABoD! <<< Kaplow Klips & Baffle:    http://nira-rocketry.org/LeadingEdge/Phantom4000.pdf www.encompasserve.org/~kaplow_r/ www.nira-rocketry.org www.nar.org
They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety. -- Benjamin Franklin Historical Review of Pennsylvania. 1759
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snipped-for-privacy@mail.iinet.net.au (Impakt) wrote:

"Optimal".
--
Jerry Irvine, Box 1242, Claremont, California 91711 USA
Opinion, the whole thing. <mail to: snipped-for-privacy@gte.net>
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Impakt wrote:

Did you drill out the nozzle or did you leave it stock?
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On Mon, 30 May 2005 15:48:07 GMT, Dave Grayvis

Stock
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(Impakt) writes:

In what motor do you join grains with tape? The HPR grains just drop inthe case together with NO joining required.
BTW, an E28 (the RMS equivalent of the E30) most certainly uses a different nozzle than the D15. So who knows what you got. It could have overpressurized the casing, especially with the 2 grains instead of 1.

I beg to differ. I saw some on the vendor table yesterday...
And the D15 is a fine motor. MUCH better than a D12 in the same model.

For that casing, NONE. The MR casings were not designed for the multi segment grains. THe only one that currently exists is for the 29/40-120 casing and it is just to get around the 62.5g limit by having 2 40g slugs.
Then there is the minor detail that this motor was not certified, thus not permitted at any NAR or TRA launch, nor in any state that follows NFPA 1122 (just about all of them).
    Bob Kaplow    NAR # 18L    TRA # "Impeach the TRA BoD"         >>> To reply, remove the TRABoD! <<< Kaplow Klips & Baffle:    http://nira-rocketry.org/LeadingEdge/Phantom4000.pdf www.encompasserve.org/~kaplow_r/ www.nira-rocketry.org www.nar.org
We must have faith in our democratic system and our Constitution, and in our ability to protect at the same time both the freedom and the security of all Americans.
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Bob Kaplow wrote:

Bob, Australia's a little way from the US (Impakt's addy ends .net.au) - I wasn't aware it had become part of the USA recently.
At least there are some Aerotech motors available over there, the UK's got none commercially available, and hasn't had for some time...
G.
--
Graham J. Platt
graham (a) bowhunter (d) demon (d) co (d) uk
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Bob Kaplow wrote:

Reading all of this, I keep thinking the same thing, especially when you figure that there was twice the surface area burning that the case is designed for.

Keep your countries straight, Bob...
-Kevin
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Well, not quite twice, but 2 extra ends where the grains were "joined". As Gary calculated, he's lucky the case didn't blow.

Whoops, just went back to the start of the thread, and noticed the .au
    Bob Kaplow    NAR # 18L    TRA # "Impeach the TRA BoD"         >>> To reply, remove the TRABoD! <<< Kaplow Klips & Baffle:    http://nira-rocketry.org/LeadingEdge/Phantom4000.pdf www.encompasserve.org/~kaplow_r/ www.nira-rocketry.org www.nar.org
"To enslave men, successfully and safely, it is necessary to have their minds occupied with thoughts and aspirations short of the liberty of which they are deprived. A certain degree of attainable good must be kept before them." Frederick Douglas, "My Bondage and My Freedom," 1855
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kaplow snipped-for-privacy@encompasserve.org.TRABoD (Bob Kaplow) wrote:

"Optimal".
--
Jerry Irvine, Box 1242, Claremont, California 91711 USA
Opinion, the whole thing. <mail to: snipped-for-privacy@gte.net>
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If an E28 reload uses a longer -single- grain,it still would have a greater surface area to burn,just from the longer C-slot. The 24-40 case is designed for impulses up to 40ns.
--
Jim Yanik
jyanik
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Jim Yanik wrote:

The grains also burn on the ends; with two grains, you have four ends burning, not two. That's a significant different in burn surface area.
Read Gary's post; 1500 psi is NOT what these cases are designed for.
-Kevin
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Thank you, Kevin. :-)
Gary
In article VwZme.36260$aB.25661@lakeread03, Kevin Trojanowski at snipped-for-privacy@nospam.cox.net wrote on 5/31/05 7:20 AM:

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Significant? How much extra area do you think those two ends add,for such a small diameter fuel slug? (compared to the longer C-slot) It's not like it were a 98mm motor with giant fuel slugs.

Total impulse comes from the mass and -velocity- of ejected gases and particulates.Velocity is related to chamber pressure and throat diameter. Does the E28 load have the same nozzle throat diameter as as D load? If the propellant burns at the same rate,to get a higher impulse,the chamber pressure has to increase,as I understand it.
--
Jim Yanik
jyanik
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Jim Yanik wrote:

D15 - .104" throat E28 - .141" throat
I would say that the addition of two ends is a greater difference on a smaller motor than on a larger one, plus you're not adding just the ends, but doubling the entire burn surface area.
Regardless, running a case beyond its design parameters is a recipe for disaster. Every time you do it, you put more stress on the hardware, which may ultimately result in it failing on a certified load.
-Kevin
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On Tue, 31 May 2005 17:13:21 -0500, Kevin Trojanowski

"I feel a great disturbance in the force!"

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