|
View Poll Results: What SU BP motor is most needed ? | |||
18mm B14-x/B8-x with at least delays of 0,3,5,7 | 17 | 33.33% | |
18mm C5-x | 11 | 21.57% | |
24mm D20-x | 4 | 7.84% | |
29mm E/F50-x | 5 | 9.80% | |
13mm B4-x | 10 | 19.61% | |
13mm 1/2A3-0T | 3 | 5.88% | |
18mm D8-x like the old Cox 13n-sec D8-0/3 | 1 | 1.96% | |
Voters: 51. You may not vote on this poll |
|
Thread Tools | Search this Thread | Display Modes |
#21
|
||||
|
||||
Quote:
If you're running a batch of C6's, where there may be a week or more of production, a day of re-tooling the line can be amortized pretty easily. OTOH, you can't afford a day of re-tooling for a half-day's worth of D8's, for example - the changeover cost will kill the pricing. That is, I don't think motor making is an exact science, altho it surely is rocket science Anyway, I suspect the amount of tweaking required for some of the exotic motors will be a deal breaker too often. I would envision something like running a hundred motors, spending a couple hours testing them, then adjusting propellant mix / tamping force / delay amount / etc, followed by another hundred units and a couple more hours testing. And that's for a well known product like a C6 or B6. It could take much longer for a D8 or D20. Now, if the process could indeed be controlled so tightly that they can just throw a switch and convert from B6's to D8's, I agree, a day's production of this niche motor could probably be profitable. OTOH, what about the batches that make it thru the two hour testing, then reach the market place only to later show some undiscovered issues resulting in a recall? That's the other issue with running small batches of niche motors, the risk of quality issues will invariably be higher. I'm not wanting to be negative, but, from a marketing perspective, it's hard to make a good case for most of these. ... One thought, first shown to me by Carl at NARCON in Austin back in 2003, was the BP motors with glued in delay elements. If the technology could be mastered such that these could be made very reliable, then the volumes could be grouped together such that the numbers would be high enough to justify production. For example, in end-burning BP motors, an 8-second delay is an 8-second delay - the delay's burn rate doesn't vary as it does with composite motors. So a production of 8-second delays would be shared over E9-8's and D12-8's and C5-8's etc. On the other end, the stamped motors would all be -0's . So all the D8's - D8-0, D8-4, D8-6 and D8-8 - would share the same batch of D8-0's thereby increasing the volume of that motor unit, and hopefully making the volume high enough to overcome the setup charges. In short, if the BP motor supply morphed into booster motors with separate delay/ejection units, the numbers might make some of these niche motors much more realizable. Doug .
__________________
YORF member #11 |
#22
|
||||
|
||||
Quote:
This is essentially what they do at the start of a day's production - or so we were given to understand on the tour on the Monday of NARAM week. Mr. Langford didn't say how many motors they make before testing to see if they need to tweak something, but they do it every time they start a new batch.
__________________
Bernard Cawley NAR 89040 L1 - Life Member SAM 0061 AMA 42160 KG7AIE |
#23
|
||||
|
||||
I'm beginning to think the best way to get B14's is to just drill cores in B4-2,4,6 engines.
The B14 is a drilled B4. Proven by measurement. Definitely against NAR schmafety code. Ask me if I give a RAT'S PATOOT ! Still leaves one without a B14-0 unless one removes the clay cap, ejection charge and delay. I have used a home-brew B14-2 booster motor in the past in an old Astron Delta. It definitely flew higher with the 2 second coast between staging.
__________________
When in doubt, WHACK the GAS and DITCH the brake !!! Yes, there is such a thing as NORMAL, if you have to ask what is "NORMAL" , you probably aren't ! Failure may not be an OPTION, but it is ALWAYS a POSSIBILITY. ALL systems are GO for MAYHEM, CHAOS, TURMOIL, FIASCOS, and HAVOC ! |
#24
|
||||
|
||||
This poll should have included the C11. I sure would welcome the return of the C11-3.
|
#25
|
||||
|
||||
If we had the C5-3 back there would be no need for the oversized, overpriced, overweight 24mm C11.
__________________
When in doubt, WHACK the GAS and DITCH the brake !!! Yes, there is such a thing as NORMAL, if you have to ask what is "NORMAL" , you probably aren't ! Failure may not be an OPTION, but it is ALWAYS a POSSIBILITY. ALL systems are GO for MAYHEM, CHAOS, TURMOIL, FIASCOS, and HAVOC ! |
#26
|
|||
|
|||
Quote:
__________________
Paul If we weren't all crazy, we would go insane - Jimmy Buffett NAR #87246 www.wooshrocketry.org |
#27
|
|||
|
|||
New Most Needed SU BP Motor
Would enjoy seeing:
13mm 1/4A3-1T 1/2A3-0T A3-2T A3-5 or 6T B4-0/3/5/7 in 2.25inch case 18mm B4-6 C5-0 C5-3 24mm C11-0, 3,5,7 Guess all had been made in the past, and could be resurrected. The B14's and other cored motors like the old FSI Loadlifters would be great, but possibly not in the cards (short term anyway). Garth Illerbrun NAR 26894 L2 |
#28
|
||||
|
||||
Quote:
Cluster a couple MMX motors!
__________________
I love sanding. |
#29
|
||||
|
||||
Poll is still open.
Still hoping for "cored" motors from the "new" Estes. Would be the biggest hobby Rocketry re-introduction since the re-kitting of old favorites by Semroc.
__________________
When in doubt, WHACK the GAS and DITCH the brake !!! Yes, there is such a thing as NORMAL, if you have to ask what is "NORMAL" , you probably aren't ! Failure may not be an OPTION, but it is ALWAYS a POSSIBILITY. ALL systems are GO for MAYHEM, CHAOS, TURMOIL, FIASCOS, and HAVOC ! |
#30
|
||||
|
||||
Quote:
I’ve got some old C5s I acquired with some B14s, but never used any of either. I plan to try both this year. But, I do like C11s. They may be oversized for some small rockets, and a tad overweight (about 10g heavier than 18mm Cs), but price is within pennies on a per motor basis. AC Supply sells C6s for $7.07 for 3, or $2.36 per motor. The C11s are $4.79 for 2, or $2.40 per motor. I’m currently building a 24mm booster for a scratch-built Farside-X. I’ll likely fly it on a C11-0 booster first flight, just to give it a nice kick at liftoff, but keep altitude reasonable.
__________________
Lee Reep NAR 55948 Projects: Semroc Saturn 1B, Ken Foss Designs Mini Satellite Interceptor In the Paint Shop: Nothing! Too cold! Launch-Ready: Farside-X, Maxi Honest John, Super Scamp |
Thread Tools | Search this Thread |
Display Modes | |
|
|