Ye Olde Rocket Forum

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


Reply
 
Thread Tools Search this Thread Display Modes
  #11  
Old 04-03-2019, 09:49 PM
blackshire's Avatar
blackshire blackshire is offline
Master Modeler
 
Join Date: Jan 2009
Location: Fairbanks, Alaska
Posts: 5,868
Default

Quote:
Originally Posted by mwtoelle
A piston would help, but only the only people that I know that would use them are competition fliers. If the A10 was actually labelled to reflect the actual average of the motor, it would be an A2 instead. I have actually flown 1974 vintage A10-0Ts, and even those motors had a long burn. I even put a comment in my flight log about to A10-0T burning about as long as an A3 motor. In the Estes catalogs of the time it was claimed that the A10s had a 0.26 sec. thrust duration. Current catalogs show the A10s with a 0.80 sec thrust duration. Personally, I think that the A10 has always had the longer duration listed in the newer catalogs. Even the data from S&T concurs with the longer thrust duration. As I have learned over the years, long burn, low thrust motors and windy flight conditions do not mix very well.
That's too bad--competition flyers don't have any special DNA... :-) The fit of the blow-off tube of a piston launcher does have to be just right, but vented gap-staging (and the Centuri Pass-Port stages) also requires/required just the right fit (so that the lower stage burn-through gases can be vented to relieve the inter-stage pressure, without blowing the two stages apart before the upper one can ignite.
__________________
Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see:
http://www.lulu.com/content/paperba...an-form/8075185
http://www.lulu.com/product/cd/what...of-2%29/6122050
http://www.lulu.com/product/cd/what...of-2%29/6126511
All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com.
NAR #54895 SR
Reply With Quote
  #12  
Old 04-04-2019, 12:36 AM
mwtoelle's Avatar
mwtoelle mwtoelle is offline
Flying since 1977
 
Join Date: Oct 2010
Location: Middle TN
Posts: 357
Default

Quote:
Originally Posted by blackshire
That's too bad--competition flyers don't have any special DNA... :-) The fit of the blow-off tube of a piston launcher does have to be just right, but vented gap-staging (and the Centuri Pass-Port stages) also requires/required just the right fit (so that the lower stage burn-through gases can be vented to relieve the inter-stage pressure, without blowing the two stages apart before the upper one can ignite.

Agreed, a piston would be helpful, but a piston launcher is tricky to use. The launch weight of a full-up Mini-Comanche-3 is the range of 2.2 - 2.3 oz. The problem with three stage model rockets is getting them safely off the ground with the motors that are available today. The Estes Farside/Farside-X, the Centuri T-Bird, and Centuri Arrow-300 were able to satisfy the demand for three stagers, but the demise of the B14-0 led to their being dropped. Even Estes decided to use D12-0s in their Comanche-3 to ensure a safer boost than was available in the older kits after the B14-0, B8-0, and C5-0s were discontinued.
__________________
'Til next time,

Mike Toelle

NAR 31692 L1

SAM 0373
Reply With Quote
  #13  
Old 04-04-2019, 12:57 AM
blackshire's Avatar
blackshire blackshire is offline
Master Modeler
 
Join Date: Jan 2009
Location: Fairbanks, Alaska
Posts: 5,868
Default

Quote:
Originally Posted by mwtoelle
Agreed, a piston would be helpful, but a piston launcher is tricky to use. The launch weight of a full-up Mini-Comanche-3 is the range of 2.2 - 2.3 oz. The problem with three stage model rockets is getting them safely off the ground with the motors that are available today. The Estes Farside/Farside-X, the Centuri T-Bird, and Centuri Arrow-300 were able to satisfy the demand for three stagers, but the demise of the B14-0 led to their being dropped. Even Estes decided to use D12-0s in their Comanche-3 to ensure a safer boost than was available in the older kits after the B14-0, B8-0, and C5-0s were discontinued.
Clustering the first stage of the Mini-Commanche-3 (adding three--or even two [although it would look unsymmetrical, but it would fly fine]--13 mm booster motor tubes on the sides of the center tube) would greatly increase the first stage's thrust and acceleration, although clustering the igniters must be done carefully, and it requires more juice than a four-AA battery launch controller can put out. Another, simpler option for the Mini-Commanche-3 would be to make a BT-20 first stage, which would house a B6-0 or C6-0 booster motor (the A10-0T first stage could be used on dead-calm--or nearly so--days).
__________________
Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see:
http://www.lulu.com/content/paperba...an-form/8075185
http://www.lulu.com/product/cd/what...of-2%29/6122050
http://www.lulu.com/product/cd/what...of-2%29/6126511
All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com.
NAR #54895 SR
Reply With Quote
  #14  
Old 04-05-2019, 12:29 PM
Newbomb Turk's Avatar
Newbomb Turk Newbomb Turk is offline
Consigliere to Bill E.'s BP Mafia
 
Join Date: Oct 2012
Location: Florida
Posts: 561
Default

Wow. Thanks for lots of great feedback. Unfortunately, the steel rod was clean, as was the lug. Neither did I note much wind at the time of launch (I'm very wary of launching in wind.)

Some post-mort pics. The surviving first stage, seemingly undeterred.
Attached Thumbnails
Click image for larger version

Name:  C post-mort 1.jpg
Views: 21
Size:  1.45 MB  Click image for larger version

Name:  C post-mort 2.jpg
Views: 16
Size:  1.61 MB  
__________________
Just completed: Estes #3228 V2, #3219 Air Commander.

Current project: Estes #7227 Apollo Little Joe II. Rescuing my Mini-Comanche III.
Reply With Quote
  #15  
Old 04-05-2019, 12:35 PM
Newbomb Turk's Avatar
Newbomb Turk Newbomb Turk is offline
Consigliere to Bill E.'s BP Mafia
 
Join Date: Oct 2012
Location: Florida
Posts: 561
Default

I'm inclined, knowing the conditions at flight time, to think GH might be right. If the A10-0T does in fact have enough oompf to power the design, perhaps this particular A10 was a less than perfect product.

Our LCO is a Physics PhD. His immediate reaction was that it didn't have enough thrust.

Note the damage sustained by the second stage upon impact with the ground under power.
Attached Thumbnails
Click image for larger version

Name:  B post-mort 1.jpg
Views: 21
Size:  1.58 MB  Click image for larger version

Name:  B post-mort 2.jpg
Views: 16
Size:  1.66 MB  
__________________
Just completed: Estes #3228 V2, #3219 Air Commander.

Current project: Estes #7227 Apollo Little Joe II. Rescuing my Mini-Comanche III.
Reply With Quote
  #16  
Old 04-05-2019, 12:40 PM
Newbomb Turk's Avatar
Newbomb Turk Newbomb Turk is offline
Consigliere to Bill E.'s BP Mafia
 
Join Date: Oct 2012
Location: Florida
Posts: 561
Default

And the launch lug...
Attached Thumbnails
Click image for larger version

Name:  accused ll.jpg
Views: 26
Size:  1.42 MB  
__________________
Just completed: Estes #3228 V2, #3219 Air Commander.

Current project: Estes #7227 Apollo Little Joe II. Rescuing my Mini-Comanche III.
Reply With Quote
  #17  
Old 04-05-2019, 01:36 PM
tbzep's Avatar
tbzep tbzep is offline
Dazed and Confused
 
Join Date: Mar 2005
Location: TN
Posts: 9,192
Default

Is the A10 nozzle eroded? That would significantly lower thrust.

Maybe some impurity got into the BP during the motor making process and lowered the thrust.
__________________
I love sanding.
Reply With Quote
  #18  
Old 04-05-2019, 04:53 PM
Newbomb Turk's Avatar
Newbomb Turk Newbomb Turk is offline
Consigliere to Bill E.'s BP Mafia
 
Join Date: Oct 2012
Location: Florida
Posts: 561
Default

It definitely looks a little different than most spent engines I've seen.
Attached Thumbnails
Click image for larger version

Name:  A10_1[1].jpg
Views: 28
Size:  1.20 MB  Click image for larger version

Name:  20190405_150817[1].jpg
Views: 35
Size:  1.15 MB  
__________________
Just completed: Estes #3228 V2, #3219 Air Commander.

Current project: Estes #7227 Apollo Little Joe II. Rescuing my Mini-Comanche III.
Reply With Quote
  #19  
Old 04-06-2019, 08:50 AM
jdbectec jdbectec is offline
the middle-aged rocketeer
 
Join Date: Sep 2006
Location: Urbana, Illinois.....the birthplace of HAL
Posts: 430
Default

That almost looks as though the propellant was was damp.Definitely not good combustion.
__________________
Jeffrey Deem
NAR16741
CIA section 527
Reply With Quote
  #20  
Old 04-06-2019, 09:20 AM
Newbomb Turk's Avatar
Newbomb Turk Newbomb Turk is offline
Consigliere to Bill E.'s BP Mafia
 
Join Date: Oct 2012
Location: Florida
Posts: 561
Default

Thanks, Jeffrey.

That was a new pack, kept in a cool, dry house and opened just before insertion.
__________________
Just completed: Estes #3228 V2, #3219 Air Commander.

Current project: Estes #7227 Apollo Little Joe II. Rescuing my Mini-Comanche III.
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 07:54 AM.


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