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  #1  
Old 03-02-2020, 03:10 PM
KILTED COWBOY KILTED COWBOY is offline
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Join Date: Oct 2019
Posts: 35
Default Cluster question

I submitted this question to the boys on The Rocketry Forum, and got some different responses.
Found out that Aerotech does not make any single use motors without an ejection charge. was concerned that the ignition times between a composite motor and a BP motor would be problem with them all igniting.
I have about 7 months a a bit of money involved in this first cluster and sure would like it not to fail. The rocket right now with out the motors is weighing in at a little over 20 oz.
Ya'll have any ideas?
Have an Estes Saturn V with a Boyce 5 motor cluster fin can.
Boyce is recommendations are an Aerotech E15-4 for center motor and
4 Estes B6-0 for the 4 outboard motors.
Never have done a 5 motor cluster before.
Do y’all think that it would be better to do all Aerotech motors?
If so what would be a good substitute for the Estes B6-0
Not sure if the Aerotech and the Estes would ignite at the same time using different igniters.
What do you experts think?
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  #2  
Old 03-02-2020, 03:39 PM
L3Excalibur L3Excalibur is offline
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Join Date: Jan 2007
Location: Minneapolis, MN
Posts: 142
Default Boyce Saturn V cluster

Quote:
Originally Posted by KILTED COWBOY
I submitted this question to the boys on The Rocketry Forum, and got some different responses.
Found out that Aerotech does not make any single use motors without an ejection charge. was concerned that the ignition times between a composite motor and a BP motor would be problem with them all igniting.
I have about 7 months a a bit of money involved in this first cluster and sure would like it not to fail. The rocket right now with out the motors is weighing in at a little over 20 oz.
Ya'll have any ideas?
Have an Estes Saturn V with a Boyce 5 motor cluster fin can.
Boyce is recommendations are an Aerotech E15-4 for center motor and
4 Estes B6-0 for the 4 outboard motors.
Never have done a 5 motor cluster before.
Do y’all think that it would be better to do all Aerotech motors?
If so what would be a good substitute for the Estes B6-0
Not sure if the Aerotech and the Estes would ignite at the same time using different igniters.
What do you experts think?

First, I think Aerotech has dropped the E15 so you would be using an E20, instead. However, I would go all black powder. Estes E12 in the center with 4 x B6-0. Or D12 plus 4 x C6-0.
Another alternative would be C6-3 in the center plus 4 x C6-0
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  #3  
Old 03-02-2020, 03:58 PM
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ghrocketman ghrocketman is offline
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Default

Use the Aerotech E30-4 T instead as the central motor.
It uses Blue Thunder propellant, which ignites as easily as black powder motors.
Do not use an E15 or E20. Those use White Lightning which often chuffs.
I would use 4 C5-3s for outboard motors.
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  #4  
Old 03-02-2020, 04:51 PM
KILTED COWBOY KILTED COWBOY is offline
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Posts: 35
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Outboard motors are in a closed plastic motor tube so has to have zero ejection charge as no way to vent the gasses..
Was looking to stay with single use motors.
I am also concerned about the Estes E motorCATOS
I would rather not ha this as a throwaway rocket
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  #5  
Old 03-02-2020, 05:09 PM
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Rocket Babe Rocket Babe is offline
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Quote:
Originally Posted by KILTED COWBOY
The rocket right now with out the motors is weighing in at a little over 20 oz.
Have an Estes Saturn V with a Boyce 5 motor cluster fin can.
Boyce is recommendations are an Aerotech E15-4 for center motor and
4 Estes B6-0 for the 4 outboard motors.
Never have done a 5 motor cluster before.



Use all BP engines.

Major questions: Are you using all 5 for ejection? Then all 5 should have the SAME delay. If not, why not? If not, where's the burn through gases of the four B6-0's going? Has to be part of ejection or vented. Otherwise, you'll have early separation and a trashed Saturn V.

Whatever engine combinations you use, as long as you have a 5 to 1 thrust ratio you'll be fine.

I use a D12-3 with 4 A8-3 (about 275 feet) or a D12-5 with 4 C6-0's. (About 450 feet) Both give a great flight and return safely.


For building tips, go here: http://www.sears572.com/supersaturnv.htm or my website http://www.vernarockets.com/id2.html


When it's built you may have more questions about launching.

Good luck!

Verna
http://www.vernarockets.com
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http://www.amazon.com/dp/B00O14ET8K
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  #6  
Old 03-02-2020, 05:17 PM
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Rocket Babe Rocket Babe is offline
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[QUOTE=KILTED COWBOY]Outboard motors are in a closed plastic motor tube so has to have zero ejection charge as no way to vent the gasses.


Then you have to "loose friction fit" them and let them kick out. That might be a problem at some fields. Some clubs don't allow you to fly rockets that kick motors.


Verna
http://www.vernarockets.com
http://www.amazon.com/dp/B00HHJHOK6
http://www.amazon.com/dp/B00O14ET8K
http://www.amazon.com/dp/B01CX1UPCG
https://www.amazon.com/dp/B07C95BNQH
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  #7  
Old 03-02-2020, 05:18 PM
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Earl Earl is offline
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As far as the outboards go, you can have them eject if the mounts are not ported. It isn’t exactly scale flight characteristics, but it can be done.

I used to fly my Centuri Saturn V with a core Aerotech E15 composite and four outboard mini-A motors. The minis were ignited via flashbulb through a micro switch on the pad that fired AFTER first motion of the Saturn when the E15 was ignited. So, no chance of just the outboards going without the E15 core. No motion on the pad from the E15, no outboard ignition. The minis were short delay full A’s, but ejected well before apogee.

Now, to be honest, that is not a simple setup by any means, but never had a failure with it. But, mucho checks of all igniters, flashbulbs, and final wiring before pressing the firing button. That setup was used to launch Saturn V’s at Kennedy Space Center three different times before large audiences during various Apollo 11 anniversaries, also with no failures, thank goodness.

Earl
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  #8  
Old 03-02-2020, 05:31 PM
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tbzep tbzep is offline
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There will be a "charge" even with booster motors. They need to be ejected, or modified by gluing in a plug (if you aren't flying with a club).

I'd go D12 and C6's until we get the C5's back or the Blue Thunder E30 like GH mentioned. They do ignite pretty quick. Just make sure your igniter is a good one and is seated properly. You don't want it to misfire and come off the rod on the C6's.

The bad thing about the E30 is you won't see much if any flame, especially on a bright day. The D12 will give you a nice longer central flame to match the outboards.

Be sure to do continuity checks on all your igniters and make sure you don't have anything shorted when you hook it all up. Hopefully you've done other clusters in rockets that you didn't put so much work into. Going for a first cluster in a Saturn V with 5 motors is begging for trouble. BTW, take pictures before the flight. If you forget, it's an almost guaranteed crash or cato.


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  #9  
Old 03-02-2020, 05:33 PM
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tbzep tbzep is offline
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Quote:
Originally Posted by Earl
As far as the outboards go, you can have them eject if the mounts are not ported. It isn’t exactly scale flight characteristics, but it can be done.

I used to fly my Centuri Saturn V with a core Aerotech E15 composite and four outboard mini-A motors. The minis were ignited via flashbulb through a micro switch on the pad that fired AFTER first motion of the Saturn when the E15 was ignited.
Earl

In the good old days you could do a simple and reliable central AP motor with outboards ignited by thermalite. Big or small, it didn't matter.
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  #10  
Old 03-02-2020, 05:39 PM
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Rocket Babe Rocket Babe is offline
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Quote:
Originally Posted by tbzep
The D12 will give you a nice longer central flame to match the outboards.
.


Like this?


Verna
http://www.vernarockets.com
http://www.amazon.com/dp/B00HHJHOK6
http://www.amazon.com/dp/B00O14ET8K
http://www.amazon.com/dp/B01CX1UPCG
https://www.amazon.com/dp/B07C95BNQH
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