Ye Olde Rocket Forum

Go Back   Ye Olde Rocket Forum > Weather-Cocked > Current Kit Talk
User Name
Password
Auctions Register FAQ Members List Calendar Today's Posts Search Mark Forums Read


View Poll Results: What SU BP motor is most needed ?
18mm B14-x/B8-x with at least delays of 0,3,5,7 16 40.00%
18mm C5-x 11 27.50%
24mm D20-x 3 7.50%
29mm E/F50-x 2 5.00%
13mm B4-x 5 12.50%
13mm 1/2A3-0T 2 5.00%
18mm D8-x like the old Cox 13n-sec D8-0/3 1 2.50%
Voters: 40. You may not vote on this poll

Reply
 
Thread Tools Search this Thread Display Modes
  #21  
Old 10-26-2018, 08:52 PM
Doug Sams's Avatar
Doug Sams Doug Sams is offline
Old Far...er...Rocketeer
 
Join Date: Mar 2005
Location: Plano, TX resident since 1998.
Posts: 3,929
Default

Quote:
Originally Posted by tbzep
However, it would be nice for Estes to set aside a day or two out of the year to run one batch of B8's, D20's or whatever niche motors they choose.
If it were that easy, it might be worth it to them. But, in my experiences changing over a line from one product to another, the recipe is not guaranteed - it can take several false starts along with a few tweaks to get everything running just right.

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
Reply With Quote
  #22  
Old 10-26-2018, 11:27 PM
BEC's Avatar
BEC BEC is offline
Master Modeler
 
Join Date: Feb 2009
Location: Auburn, Washington
Posts: 2,368
Default

Quote:
Originally Posted by Doug Sams
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.


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
Reply With Quote
  #23  
Old 10-27-2018, 05:03 PM
ghrocketman's Avatar
ghrocketman ghrocketman is offline
President, MAYHEM AGITATORS, Inc.
 
Join Date: Jul 2005
Location: Michigan
Posts: 8,974
Default

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 NEVER touch the brake !!!
No Harm=NO Foul advocate

If you are NOT FLYING LOW in the left lane, you need to GET THE #$&@ OUT of it !

Yes, there is such a thing as NORMAL
, if you have to ask, you probably aren't
!
Reply With Quote
  #24  
Old 10-27-2018, 05:33 PM
neil_w's Avatar
neil_w neil_w is offline
Mr. Cut-by-hand
 
Join Date: Nov 2015
Location: Northern New Jersey
Posts: 336
Default

This poll should have included the C11. I sure would welcome the return of the C11-3.
Reply With Quote
  #25  
Old 10-27-2018, 07:40 PM
ghrocketman's Avatar
ghrocketman ghrocketman is offline
President, MAYHEM AGITATORS, Inc.
 
Join Date: Jul 2005
Location: Michigan
Posts: 8,974
Default

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 NEVER touch the brake !!!
No Harm=NO Foul advocate

If you are NOT FLYING LOW in the left lane, you need to GET THE #$&@ OUT of it !

Yes, there is such a thing as NORMAL
, if you have to ask, you probably aren't
!
Reply With Quote
  #26  
Old 10-28-2018, 08:43 AM
PaulK's Avatar
PaulK PaulK is offline
BAR
 
Join Date: Nov 2005
Location: WI
Posts: 1,164
Default

Quote:
Originally Posted by neil_w
This poll should have included the C11. I sure would welcome the return of the C11-3.
And the C11-0, I fly those quite a bit. For smaller models, the C5-0 is nearly as good, but for heavier 24mm 2 stagers, the C11 has more lifting power, the burn time is about half that of the C5. Fortunately, I have a decent stash of both C5-0 and C11-0 motors.
__________________
Paul
If we weren't all crazy, we would go insane - Jimmy Buffett
NAR #87246 www.wooshrocketry.org
Reply With Quote
  #27  
Old 10-31-2018, 08:28 AM
Quixote Quixote is offline
Intermediate Rocketeer
 
Join Date: Apr 2009
Posts: 38
Default 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
Reply With Quote
  #28  
Old 10-31-2018, 08:30 AM
tbzep's Avatar
tbzep tbzep is offline
Dazed and Confused
 
Join Date: Mar 2005
Location: TN
Posts: 8,819
Default

Quote:
Originally Posted by Quixote
Would enjoy seeing:

13mm
1/4A3-1T

Cluster a couple MMX motors!
__________________
I love sanding.
Reply With Quote
  #29  
Old 12-27-2018, 07:22 AM
ghrocketman's Avatar
ghrocketman ghrocketman is offline
President, MAYHEM AGITATORS, Inc.
 
Join Date: Jul 2005
Location: Michigan
Posts: 8,974
Default

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 NEVER touch the brake !!!
No Harm=NO Foul advocate

If you are NOT FLYING LOW in the left lane, you need to GET THE #$&@ OUT of it !

Yes, there is such a thing as NORMAL
, if you have to ask, you probably aren't
!
Reply With Quote
  #30  
Old 12-27-2018, 08:15 PM
LeeR's Avatar
LeeR LeeR is offline
Retired with Way Too Many Kits
 
Join Date: Jun 2007
Location: Colorado
Posts: 1,913
Default

Quote:
Originally Posted by ghrocketman
If we had the C5-3 back there would be no need for the oversized, overpriced, overweight 24mm C11.


Iíve 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.

Iím currently building a 24mm booster for a scratch-built Farside-X. Iíll 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, L2

Projects: Super Sky Hook, Estes Saturn V, Astron Farside-X
In the Paint/Detailing shop: Estes Saturn 1B
Completed!: Der Saturn Max
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump



All times are GMT -5. The time now is 09:58 AM.


Powered by: vBulletin Version 3.0.7
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
Ye Olde Rocket Shoppe © 1998-2019