"Air Starting" All Motors In Cluster

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bguff

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Does anyone ever "air start" all the motors in their cluster rockets? If so, is there any webpage detailing their efforts?

It's occurred to me that if my launch controller threw a relay embedded in a cluster rocket, and i have batteries with appropriate amps/volts embedded in the cluster rocket, i wouldn't have to worry about all motors lighting prior to the rocket leaving the pad.

I have a scale rocket where i would like to light 5 identical propellant/size motors, so a larger central motor is out of the question.

Bob
 
I'm puzzled by you statement,

If you air-start all of the motors then what will lift it off of the ground?




JD
 
I think what he's saying is he wants to mount the power source for ignition inside the rocket so that the ignitors and associated wiring/clip whip doesn't jerk out of the motors as soon as a couple motors come up to pressure but ride along giving latecomers a chance to ignite.
 
Peartree said:
I think what he's saying is he wants to mount the power source for ignition inside the rocket so that the ignitors and associated wiring/clip whip doesn't jerk out of the motors as soon as a couple motors come up to pressure but ride along giving latecomers a chance to ignite.
Click to expand...

Yes, that is what i mean.
 
You can use something like a Missileworks PET timer to light motors onboard with e-matches. I"ve done it with a 10 motor cluster. 1 to lift it and 9 inthe air.

Edward
 
bguff said:
Does anyone ever "air start" all the motors in their cluster rockets? If so, is there any webpage detailing their efforts?

It's occurred to me that if my launch controller threw a relay embedded in a cluster rocket, and i have batteries with appropriate amps/volts embedded in the cluster rocket, i wouldn't have to worry about all motors lighting prior to the rocket leaving the pad.

I have a scale rocket where i would like to light 5 identical propellant/size motors, so a larger central motor is out of the question.

Bob
Click to expand...
Bob

Look at Boris Katan's Toginator thread. He's the CMASS cluster guru. His trick it to hand make his igniters, and test everyone one of them before and after installation, and to use a series/parallel combination approach to the wiring to reduce the current.

He knows what he's doing. The Toginator has 26 BP motors and he get 26 out of 26 to light.

Bob
 
I would like to light 5 Aerotech G64's. I would move to redline Gs if the white lightning is problematic.
 
Doing what you're talking about will help solve the problem of an igniter attached to the controller getting yanked out.

But it won't solve the problem of assymetric thrust.

To address the latter, you either need to cant your motors towards the CG of the rocket (ala Fliskits Deuces Wild and Tres, as well as our Delta III boosters), or make sure you get all the motors up to pressure at pretty much the same time.

Cleaning any oxidation off of the grains and using good, matching igniters will help on getting everything up to pressure.

-Kevin
 
bguff said:
I would like to light 5 Aerotech G64's. I would move to redline Gs if the white lightning is problematic.
Click to expand...
Boris routinely launches his Ultimate Fireball, a 7 motor APCP cluster and lights them all using his igniters and series/parallel combinations.

All it really takes is attention to detail. It took 2 hours to prep his Toginator, a 26 BP motor, I-impulse monster.

Again check out his igniter post.

https://www.rocketryforum.com/showthread.php?t=44798

Bob
 
troj said:
To address the latter, you either need to cant your motors towards the CG of the rocket (ala Fliskits Deuces Wild and Tres, as well as our Delta III boosters), or make sure you get all the motors up to pressure at pretty much the same time.
-Kevin
Click to expand...

My plans call for a canted motor mount.
 
bobkrech said:
Boris routinely launches his Ultimate Fireball, a 7 motor APCP cluster and lights them all using his igniters and series/parallel combinations.

All it really takes is attention to detail. It took 2 hours to prep his Toginator, a 26 BP motor, I-impulse monster.

Again check out his igniter post.

https://www.rocketryforum.com/showthread.php?t=44798

Bob
Click to expand...

Yes, i've read Boris's threads. I'll reread them again.
 
White Lightning is the HARDEST to ignite AP propellant from Aerotech...lousy choice for first-time AP clustering. Do you need the White Lightning for some "scale-like" exhaust effect ?
I suggest instead of G64 reloads, you go with G76G Mohave Green reloads, which is as easy to ignite as Blue thunder (VERY easy). Redline is not as bad as White Lightning, but is more difficult than Mohave Green or Blue Thunder.

How 'bout a nice cluster of G669N Warp-9 reloads ?
That would git-a-moovin' in a hurry !
(if not shred-o-matikk !)
 
ghrocketman said:
White Lightning is the HARDEST to ignite AP propellant from Aerotech...lousy choice for first-time AP clustering. Do you need the White Lightning for some "scale-like" exhaust effect ?
I suggest instead of G64 reloads, you go with G76G Mohave Green reloads, which is as easy to ignite as Blue thunder (VERY easy). Redline is not as bad as White Lightning, but is more difficult than Mohave Green or Blue Thunder.
Click to expand...

Interesting... Everything I've read, heard, etc says that black/smokey is the hardest to light, followed by green, then red, white and blue, in that order.

I've not burned much smokey, but the list otherwise matches my experience, and what I've seen.

Biggest problem with white is oxidation of the magnesium. Clean that off, and it lights really easily.

-Kevin
 
troj said:
Interesting... Everything I've read, heard, etc says that black/smokey is the hardest to light, followed by green, then red, white and blue, in that order.

I've not burned much smokey, but the list otherwise matches my experience, and what I've seen.

Biggest problem with white is oxidation of the magnesium. Clean that off, and it lights really easily.

-Kevin
Click to expand...

That's the order i understood too. Scraping the oxidation off is a definite. Might even paint some pyrogen or something on the top grain (think that idea can be attributed to Boris).
 
Yeah, it should be very easy to ignite White Lightnings as long as the white oxidation is removed, unless you get a 'fresh' motor that was made recently. I've only two misfires with AP over all and the misfire that happened with the WL propellant was user error. The other misfire I had was with an old G80 (I think it was made before the fire with AT), which was actually shocking. But a First Fire Jr. got it up and running quickly. Any ways, I just wanted point out that good motor ignition techniques are the key.
 
troj said:
Biggest problem with white is oxidation of the magnesium. Clean that off, and it lights really easily.
Click to expand...

In some loads, I've noticed that the grain that comes in the liner can be quite oxidized, while the others that come in sealed little baggies are not. I noticed this yesterday at a launch particularly, where the grain in the liner from an H128 load had a ton of oxidation, and the baggied ones were pristine. My solution has always been to stick the grain(s) with no oxidation at the forward end where the igniter goes, no sanding required with a good igniter. Is this just dumb luck, or have others seen this? I wouldn't think the little baggies would be very effective at keeping out oxygen (most plastics are quite permeable to oxygen) - and the whole reload kit is of course sealed in a bigger plastic bag. Does this have more to do with age or different handling at the factory? If so, might be nice if AT baggied all the grains.
 
AndyC2 said:
In some loads, I've noticed that the grain that comes in the liner can be quite oxidized, while the others that come in sealed little baggies are not. I noticed this yesterday at a launch particularly, where the grain in the liner from an H128 load had a ton of oxidation, and the baggied ones were pristine. My solution has always been to stick the grain(s) with no oxidation at the forward end where the igniter goes, no sanding required with a good igniter. Is this just dumb luck, or have others seen this? I wouldn't think the little baggies would be very effective at keeping out oxygen (most plastics are quite permeable to oxygen) - and the whole reload kit is of course sealed in a bigger plastic bag. Does this have more to do with age or different handling at the factory? If so, might be nice if AT baggied all the grains.
Click to expand...

Had not thought of putting the less oxidixed grain nearest to igniter. I'll have to do that from now on.
 
AT does everything as cheaply as possible, if they could ship them without bagging them,they would. the one unbagged slug should be shipped in the liner.
 
Josh,It may just be that I am scraping the oxidized slugs prior to installation. It seems any extra loose stuff on the grains ignite first,thus helping ignition. Of course I could just be imagining all this.
 
jimzcatz said:
Josh,It may just be that I am scraping the oxidized slugs prior to installation. It seems any extra loose stuff on the grains ignite first,thus helping ignition. Of course I could just be imagining all this.
Click to expand...

Oh. I thought that you meant oxidized grains that weren't cleaned up prior to flight. I understand now.
 

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