Ye Olde Rocket Forum

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


Reply
 
Thread Tools Search this Thread Display Modes
  #51  
Old 12-25-2014, 09:17 PM
billspad's Avatar
billspad billspad is offline
MMXCVII
 
Join Date: Jan 2007
Location: Saugus, MA
Posts: 371
Default

Quote:
Originally Posted by blackshire
It's been a while since I read about this, but I believe the 6 mm diameter Quest MicroMaxx booster motors (which weren't exactly "NAR Kosher/Halal," because they were modified *after* manufacture, although not--I think--by Quest) had delay charges (being modified single-stage motors), but that their delays were so short--just 1 second--that it wasn't a problem.



Quest MicroMaxx "booster" motors are designated 1/8A.5-NE and are NAR certified. They are the 1 second delay motors with the ejection charge removed by Quest. The NE means No Ejection and they weren't sold as booster motors although, in the right model, they will work as such.
Reply With Quote
  #52  
Old 12-25-2014, 09:34 PM
STRMan's Avatar
STRMan STRMan is offline
Master Modeler
 
Join Date: Nov 2007
Posts: 873
Default

That could be interesting... Stage a rocket with a D-12 first stage into a pair of sequential Micromax NE motors, then into another 24mm sustainer.
__________________
"AND I hope they are from the planet of the "Chunk spunky Mary-Lou Retton clones". - Ironnerd

"Those who trade liberty for security have neither" - Benjamin Franklin

"Semroc is almost always the answer" - Stefanj

www.paulsavia.com

www.soundclick.com/paulsavia
Reply With Quote
  #53  
Old 12-26-2014, 11:56 PM
blackshire's Avatar
blackshire blackshire is offline
Master Modeler
 
Join Date: Jan 2009
Location: Fairbanks, Alaska
Posts: 6,507
Default

Quote:
Originally Posted by billspad
Quest MicroMaxx "booster" motors are designated 1/8A.5-NE and are NAR certified. They are the 1 second delay motors with the ejection charge removed by Quest. The NE means No Ejection and they weren't sold as booster motors although, in the right model, they will work as such.
Those are the ones. Like I said, it's been a while since I read about them.
__________________
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
  #54  
Old 11-26-2015, 10:18 PM
blackshire's Avatar
blackshire blackshire is offline
Master Modeler
 
Join Date: Jan 2009
Location: Fairbanks, Alaska
Posts: 6,507
Default

Quote:
Originally Posted by Solomoriah
Really, astronwolf, don't behave as if I'm a newbie here. I was pretty sure the ejection charge would kick the sustainer out of line, but I was hoping to find someone with actual first-hand knowledge of the issue. jbuscaglia, Daddyisabar, and the venerable ghrocketman have all provided useful first-hand knowledge of the subject; your interjection was unneeded.

Heh. If nothing else, I figured gh was crazy enough to have tried it.
This is mentioned in the multi-staging chapter of G. Harry Stine's "Handbook of Model Rocketry" as part of a warning not to do it, due to "power-prangs," *but*...with an optimally massive (not too light, not too heavy) model (especially if it had a canted fins-imparted spin), it should work just fine. Although it's likely easier to do reliably with dual electronic staging ignition timers (two being used for greater reliability), such delayed staging does have legitimate uses, particularly for more realistically mimicking the flight profiles of multi-stage sounding rockets (in which there is usually significant delay between the ignition of their various stages).
__________________
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
  #55  
Old 11-10-2017, 01:33 AM
blackshire's Avatar
blackshire blackshire is offline
Master Modeler
 
Join Date: Jan 2009
Location: Fairbanks, Alaska
Posts: 6,507
Default

Quote:
Originally Posted by Solomoriah
I was reading about dual burn engines, where the engine burn pauses, the rocket coasts upward, and then the burn resumes. It's supposed to allow a rocket to reach a higher altitude.

So my question... will the ejection charge of a standard engine ignite an upper stage? Or is the rocket doomed to tumbling and lawn-darting?

In other words, could I fly a 2 stage rocket with, say, a B6-2 initial stage?
I happened across this thread again while searching for something else, and it occurred to me that there is a way to make such a "dual-pulse" solid motor using two model rocket motors (more on this below), and:

The quasi-ballistic (also called semi-ballistic) Boeing AGM-69 SRAM--Short Range Attack Missile (which would make an interesting scale model rocket, see: http://www.google.com/search?ei=x0g...1.0.V3XCEDsLnt4 )--used a dual-pulse solid rocket motor. The B-52-launched and FB-111-launched SRAM could fly off in any direction, even making "over-the-shoulder" launches in order to strike land targets *behind* the launching aircraft, and it could also function as a high-supersonic, relatively low-altitude cruise missile. Its dual-pulse rocket motor, in which the second propellant grain (which was separated from the first one by an insulating, blow-out bulkhead) could be ignited at any desired time, gave the SRAM its versatile and rather uncanny capabilities. (The Soviet--now Russian--Raduga Kh-15 air-launched quasi-ballistic missile [see: http://www.google.com/search?ei=E1M.....0.9WH24vxjzm4 ], which is very similar to the SRAM, also uses a dual-pulse solid rocket motor.) Now:

You could achieve a rather similar--although "pre-programmed"--dual-pulse motor profile by placing a black powder model rocket motor above a re-loadable composite propellant motor (using the common "taped butt-joint" staging method), which would be prepared with a delay charge but *without* an ejection charge. (A small amount of ejection charge powder [or perhaps Pyrodex], placed atop the delay charge, would ignite the black powder upper stage motor after the composite motor's delay charge had burned.) Also:

Gap-staging such a motor combination would also be possible, although it would probably be prudent to use some kind of retention system to keep the "upper stage ignition powder" atop the delay charge in the composite lower stage motor (so that the powder couldn't "fall upward" and out of the lower stage motor due to its inertia, when the rocket began to coast after the lower stage ceased thrusting); a disc of model airplane tissue might do the job. Retaining the lower stage motor's ignition powder would be especially important in models with "open-air gap-staging" (scale models of the Aerobee vehicles, the Cuckoo-boosted Skylark sounding rockets, the Iris and Hydra-Iris, the INTA-255, the Boosted Arcas I, etc.), plus:

Arranging the two motors to produce a two-pulse tandem motor (in which the upper motor would thrust down through the lower motor, but the two motors would *not* separate [this has been done many times with black powder motors, often a 13 mm motor atop an 18 mm booster motor]) would enable a "pre-programmable" dual-pulse flight profile to be used. This would provide scale realism for flying models of the SRAM, Kh-15, and other dual-pulse (not to be confused with *dual-thrust*) solid propellant vehicles.
__________________
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
  #56  
Old 11-10-2017, 03:35 AM
Rex R Rex R is offline
Craftsman
 
Join Date: Feb 2011
Posts: 473
Default

I played with this in open rocket some time back, some things to consider; the high impulse short duration thrust usually has a lower average speed than the long burn lower thrust rocket. for the delayed ignition staging events(simulated) I got the best results if the 2nd ignition took place at 1/2 the staging speed(stages separate at 1st stage burnout). it was/is my belief that the delay allowed the sustainer to gain a small advantage from decreased air density.
Rex
Reply With Quote
  #57  
Old 11-10-2017, 04:12 AM
Rex R Rex R is offline
Craftsman
 
Join Date: Feb 2011
Posts: 473
Default

another item for consideration; the thrust duration of a booster motor is shorter than a non-booster motor by about a tenth of a second.
Rex
Reply With Quote
  #58  
Old 11-10-2017, 05:33 AM
blackshire's Avatar
blackshire blackshire is offline
Master Modeler
 
Join Date: Jan 2009
Location: Fairbanks, Alaska
Posts: 6,507
Default

Thank you for posting this information and your findings! The comparison between the flight profiles of dual-pulse quasi-ballistic missiles and dual-pulse model rockets is interesting:

The only dual-pulse vehicles I've read about in detail (the SRAM and its Kh-15 counterpart [some other missiles, such as anti-tank missiles, utilize multi-pulse propulsion]) flew/fly (the Kh-15 is still deployed by the Russian military) in either parabola-like quasi-ballistic trajectories or in high-velocity horizontal flight. The lofted, parabola-like trajectory utilizes the first thrust pulse to propel the missile into the flight path, and the second pulse to generate a very high speed (about Mach 5 in the case of the Kh-15) descent to its target, which makes defending against such missiles very difficult, and causes even more destruction in the case of the non-nuclear-armed version of the Kh-15 (which also has a nuclear-armed version). The second pulse can also be used to "stretch out" the trajectory horizontally, to achieve greater range to reach a more distant target. However:

The F-15-launched ASM-135 ASAT (the air-launched anti-satellite missile, see: http://www.google.com/search?source...1.0.4jwYYgMW0dg ), which used a SRAM two-pulse solid rocket motor as its first stage, flew a trajectory that was more like that of a model rocket, and:

For model rocket use, the relatively low velocity produced by the first thrust pulse would create less drag, and the greater mass of such a model (having a tandem, two-pulse motor) should result in it being slowed down less by drag (since it would have a greater mass per unit of frontal area). Also:

Your simulation's results (that for a two-stage [with separating stages], delayed-ignition model, having the second stage fire at 1/2 the staging velocity [when the first stage separates and drops away] gives the best results) sound intuitively correct to me, although of course I haven't tested such a staging arrangement in actual flight. The lower average speed should result in lower drag and less altitude loss due to drag (the slightly lower booster-imparted velocity, due to its slightly shorter thrust duration, should also serve to lessen the drag). At some point, though, reducing the initial impulse further (by using a lower-impulse booster motor; say, an A8-0 instead of a C6-0), while it will definitely cut down the drag, just won't hurl the model up high enough for the drag reduction to be worthwhile. In addition:

This is an area where a two-pulse tandem motor, having more mass, would give a model more momentum (because of the model's greater mass/frontal area ratio) than a two-stage delayed ignition model whose upper stage had the same drag coefficient as the two-pulse tandem motor-equipped model, because the upper stage--containing one motor instead of two in tandem--would be lighter and more easily slowed by drag. These are interesting considerations to sift, weigh, and compare...
__________________
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
  #59  
Old 11-10-2017, 07:29 AM
ghrocketman's Avatar
ghrocketman ghrocketman is offline
President, MAYHEM AGITATORS, Inc.
 
Join Date: Jul 2005
Location: Nunya Bizznuss, Michigan
Posts: 13,443
Default

I LIKE full-force core-sample style POWR-PRANGS when I'm not the rocket owner. Hilarity at it's finest.
__________________
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, and HAVOC !
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 02:13 PM.


Powered by: vBulletin Version 3.0.7
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Ye Olde Rocket Shoppe © 1998-2024