Re: Taking Ejection Charges out of motors

Thank You David - I had not thought of the booster motors not having B.P. > in

> them. I quess the obvoius answers are the ones easily missed. I always > have booster estes engines for my commanche 3. I will try the technique > with the aerotech engines when I need something more powerful than a D. I > just wanted to make sure it was not dangerous to peel back the paper cap.

Just make sure you *do* plug them, the burnthrough on a D12-0 (for example) is quite capable of separating your rocket at the most inconvenient time, and probably isn't too good for it either!

I found out the hard way about this :-( I would recommend plugging well in advance with epoxy, and making sure its properly cured. Not mixing up some

5-minute on launch day and getting it wrong :-(

I've also seen hot-melt glue used with equal success, and if you decide you want to turn your D12-P back to a D12-0 you can easily peel out the glue.

Alternatively I guess you could use a blanking disc in front of the motor, though you might end up kicking the casing, which may or may not be a bad thing.

Good luck,

Niall

Oh yeah, I'm referring to Estes motors above. No personal experience of AT, but as others say the ejection charge is easily removable.

Reply to
Niall Oswald
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There is no need to plug a D12-0 to make a D12-P when you can buy pre-plugged D11-Ps.

Any motor so modified would definitely not be legal for NAR/TRA launches, and may violate state or local regs as well.

Although I do know that in the past the internates RCRG team used to make practice D12-P motors by removing the ejection and pludding D12-**3** motors. Turns out the delay is needed to prevent blowthrough of the plug.

Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD!

Reply to
Bob Kaplow

I'm not sure pudding would make a very effective plug. Well, maybe if it was chocoloate...

Reply to
Christopher Biow

What if you don't have any D11-Ps? What if your vendor doesn't?

Irrelevant in the UK.

Chris

Reply to
Chris Eilbeck

*When you can buy D11-P's* - that's the catch.

Unfortunately you can't just walk into a model shop and get them - the last one I went into told me that you couldnt get anything bigger than a C6!

Availability from on-site vendors also varies, sometimes Rockets and Things have plenty of every variant of Estes D, other times not.

The only D motors I've had a problem with have been D11's, they seem to always have the dusty 'Poopy Clay' nozzles, which can be a pain.

Niall

Reply to
Niall Oswald

Somewhere, G Harry Stine is frowning

Reply to
TheGreatIIS

Myth.

In fact, the early days had people using b.8.2 as boosters by removing the ejection charge and paper cap.

I have a early NAR model racketeer talking about delayed staging with b.8.2 motors that describes it.

Its our lawyer filled society , not Mr. stine that is frowning.

Reply to
AlMax

Interesting. I helped two of my nephews fly D Alltitude staging C5-3 to C6-7, with the ejection charge and clay cap in place. Upper stage ignition relliability was 50% but the sample size was very small. With the old paper cap motors, you must remove the cap to keep it from blocking the nozzel. The clay cap is simply pulverized and does not block the nozzel. Either way, I think the ejection charge would aid upper stage ignition.

Alan

Reply to
Alan Jones

snip

Alan, if I understand your post correctly, I bet that was an interesting flight. Please explain in more detail what you were flying, the configuration and why you chose to do this? How many flights have you tried staging a C5-3 to a C6-7 and what was the success rate? I can't think of many situations using Estes type birds where staging with a delay would be feasible. Do you think using the delay, aided upper stage ignition more than using regular boosters?

This just sounds really intersting to me.

Randy

Reply to
<randyolb

Either way, I think the ejection charge would aid

one might think so, but no.

for the same reason one puts holes in between the booster and sustainer stages in pop-in-go staging.

extra pressure pops the stages apart before they can stage.

easy going slow pressure and hot gaseous bits allow the stage above to light correctly.

I have many 18mm outside staging couplers with holes in them , centrui style.

Art

Reply to
AlMax

By venting properly, I've been able to simultaneously chad stage 5 to 5,

10.5" apart. You have to vent all the stuffer tubes and the main bt.

Randy

Reply to
<randyolb

IIRC this was in D Altitude at NARAM-30. Adults were flying F altitude, but the kids flew a lower impulse class, Rather than D12s, Alan's nephew used the C5-3:C6-7 combination for lower diameter and better altitude. I think one of them may have placed.

I think I used a Quest C6-3:1/2A3-4T combo in C altitude a few years back. It staged, but the upper stage was never seen again, by trackers or me.

Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD!

Reply to
Bob Kaplow

It is the flaming bits that actualy ignites the upper stage, not just hot gasses. I was questioning if the bits of delay grain burn as hot (or hot enough) as the ejection charge, and if the delay grain burns with enough booster chamber pressure to propel the flaming bits of delay grain forward into the upper stage nozzel.

I prefer the Estes staging method, buy yes the Centuri method works also.

Alan

Reply to
Alan Jones

Thanks Alan & Bob. That was very interesting and gives me some new ideas for future set ups. I'd love to see some delayed 2 stage flights.

Randy

Reply to
<randyolb

Hmmm, Dan is still the older brother. Dan gaduated from ISU with a ME degree and is working for Hon in Iowa as some sort of plant engineer or manager. Phillip is nearing completion of his education at the U of I.

Alan

Reply to
Alan Jones

Removal of most of the clay, leaving the ejection will improve staging reliability to about 90% in my experience. This is with taped together motors, not gap staging.

Tom

Reply to
Tom Binford

Alas, not allowed at NAR or TRA launches...

Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD!

Reply to
Bob Kaplow

Realistically it is RSO subjective, even at those launches.

Reply to
Jerry Irvine

yes, the extra flaming bits of ejection charge would ignite the upper stage better then a delay grain.

BUT, that is only if they get their first. the extra pressure of the blast pushes the part apart way too fast for 100% ignition.

using some kind of venting could increase that to almost perfect I bet

heck, I bet that might be a good R&D for someone.

Reply to
Almax

Depends on the diameter of the nozzle. The bigger, the better, if you're gap staging.

Randy

Reply to
<randyolb

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