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LOC Bruiser Ejection Charge Question

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EBurg

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I'm finishing up my LOC Bruiser and going for my L2 certification flight at Midwest Power in November. I'm planning on using an Aerotech J420 for the flight, which sims out around 1200' for a nice low flight. My question is how to handle the ejection charge... Looking at the calculators I think I will need around 3g of black powder, which is more than will fit in the 38mm forward closure. Can I build it up with masking tape to make a larger well? Hoping to use motor ejection on this flight and not use electronics. Anyone ever use straight motor ejection on this rocket?

Eric
 

fyrwrxz

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Yep- back in the day. Always used 2 extra g of 4f in a tape well made by wrapping 3-4 turns around the end, dumping in powder and dog barf then crisscross 3x and i wrap again around end. Prolly overkill but it always got the laundry out. PITA to clean up forward closure but it worked every time. I just used blue tape. Make absolutely sure you don't get any grease on the delay and tap the well as you fill it to make sure it goes down and sits on the delay element. loved that bird but donated it to a Science teacher for his classroom somewhere out it the desert by El Centro. If anybody sees an ugly dark blue Bruiser hanging in a Inland Empire school, lemme know, I'd like to bring it home.
 
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ECayemberg

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Hey Eric,

Another Eric at MWP....I'll have my Bruiser there as well. Like Kurt said, not so many people using a Bruiser in this fashion nowadays but in the old days they were flying on I284's and J275's all the time with motor eject. A J420R is right in between and will work just fine as long as you built it light-ish and use enough BP to get that chute out.

Let me know if you need any help...I'll be there Saturday and Sunday and can help with the cert if needed.

-Eric-
 

EBurg

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Thanks guys -
Looks like I'll be adding to the motor charge until I get a total of about 3.5g... I'll be creative with the blue tape cup to make it work.

I'll look out for you Eric - thanks for the offer.
 

EBurg

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Eric C - how much black powder do you use with your Bruiser?
 

jrkennedy2

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My Brusier EXP (tri-motor, 2, 4gr Is and 1, 4gr K 740 cstar) uses 4gr FFFF in a dual deploy config, fore and aft. It's a bit "energetic" but I want "laundry" assured as I don't run redundant DD systems.
 

ECayemberg

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Eric C - how much black powder do you use with your Bruiser?
So my Bruiser is a bit unconventional....it has the same physical size and attributes of a standard Bruiser, but is set up for dual deploy out of a internal chute cannon and has a 98mm mount....first flight was on an N. In order to balance, it has a decent amount of nose weight. I have a Warlock I picked up on the cheap that I'll probably turn into a more conventional Bruiser at some point, using a Jolly Logic chute release for dual deploy.

Back to the original question, I'm with JR, I think 4-ish grams would be a good starting point. I too am a fan of "blow it out or blow it up"....I don't like ballistic rockets! Biggest recommendation I'd have is to ground test. Place a small piece of tape to close off the tiny hole in the forward closure, add your 3.5 or 4 grams of BP on top of that, pack the cord, chute, nosecone as you would for flight, ignite the charge remotely using an electric "starter/lighter". Stand back and out of the way of the booster and cone; if you get clean separation as intended, you know you're good to go. Too wimpy, add powder and try again. Too energetic (no such thing :wink:), decrease BP and try again. Ground testing is priceless, IMO!

-Eric-
 

dshmel

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I'm finishing up my LOC Bruiser and going for my L2 certification flight at Midwest Power in November. I'm planning on using an Aerotech J420 for the flight, which sims out around 1200' for a nice low flight. My question is how to handle the ejection charge... Looking at the calculators I think I will need around 3g of black powder, which is more than will fit in the 38mm forward closure. Can I build it up with masking tape to make a larger well? Hoping to use motor ejection on this flight and not use electronics. Anyone ever use straight motor ejection on this rocket?

Eric
I have used motor ejection before on my Bruiser a couple of times. IIRC, I filled the ejection wells until the BP was slightly rounded, then covered with tape. I had no issue.
 

dshmel

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Hey Eric,

Another Eric at MWP....I'll have my Bruiser there as well.

-Eric-
HMMMM, sounds like a potential Bruiser drag race? Dunno if I have room in the SUV since I will be bringing my Terminator, Demon 98, and a couple of other 4" diameter rockets.Bruiser.jpg
 
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jrkennedy2

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SCUD.jpg

Decided to give all those Patriot flyers a target...

[video]https://dl.dropboxusercontent.com/u/67135418/Video%20Aug%2020%2C%2012%2005%2027%20(2).mov[/video]

Must be a southern hemisphere launch? Some playbacks, its upside down...
 
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