- This topic has 36 replies, 5 voices, and was last updated 19 years, 1 month ago by
Bruce R. Schaefer.
Bruce R. Schaefer.-
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Bruce R. Schaefer
Doug, that was perfect, and at 0.5 grams. I noticed that you didn’t use a chute. I’ve never tried it without one. Do you get reliable results if you don’t? I mean it makes sense, tired of damages chutes! 🙄
Doug Gerrard
I will probably use a small chute on the flight, just left it out for the test. For the drouge compartment I have 5″ for chute space but another 9″ for the coupler. When I tested at 0.3 gms it sheared the screws but couldn’t blow apart the sections. After it move a total of about 7″ it stopped because the the vacuum that was starting to create inside the compartment. At 0.5 gms it was just about right to gently blow them apart.
The 2 gm shot is the one I was recommending you look at. With the piston it quite easily separates the two sections…
Doug
Bruce R. Schaefer
Holy… and that was 2 grams?! That was good! From what I remember from my 2 gram event, that was about right, only I wasn’t using a piston. Lots of flame to singe my chute. Quite easily separates the 2 sections? Intended understatement. You could say that. 🙂 You’d need a mile harness to absorb that easy separation. That was just so cool. 😀 I got some 4-40’s at work today, and I’ll drill the holes tonight. What’s a good bit size for 4-40’s? I’ve gotta go watch that again…
Conway Stevens
Not to change topics BUT has me curious. I planned on a 36″ drouge chute with roughly 55 to 60lbs of rocket flying to 13 to 14k in alt. Its a Tac chute or square cut chute with no spill hole. Wondering if it may be to much. Many others directed towards.
Bruce R. Schaefer
Don’t know if this will help, Conway:
Doug Gerrard
I planned on a 36″ drouge chute with roughly 55 to 60lbs of rocket
I have debated myself on the use of a drogue at all. I prefer not having a drogue except for one thing. I have seen drougeless dual deployments that spin the fin can until everything gets all would up and the main fails to fully open. My thoughts are to use a small (about 24″ to 36″) chute on the rocket also weighing about 50 pounds just to keep it from tumbling. I’ve also considered just a streamer for the same reason. I also plan on attaching the drogue towards the outer edge of the bulkplate instead of in the center again to keep it stable.
Doug
Conway Stevens
Thanks Doug and Bruce. Doug you hit the nail right on the head as to what my beliefs/experince is as well as what others have told me. My last project (which Dave Hanson now owns and flys) was a drougeless deployment worked great even from close to 15k. BUT it was also a much smaller rocket weighing in at 8 to 10 lbs. Not the 50 to 55 lbs my L3 will weigh. I think I will stick with the 36″ drougechute. I think I will or at least should be fine.
Bruce R. Schaefer
In my first L2 attempt (bird ~6 pounds), I had the main chute stick (definitely my fault, NEVER hurry!), BUT the rocket separated and was balanced. Fell a couple of thousand feet almost flat. No problem, essentially no damage. In a well-balanced bird, a drogue isn’t necessary–as JW pointed out earlier in this or another thread. Thought I was gonna find a new white fence post on the prairie. A drogue would have pulled it up, causing a nose and tail crash. You never know what works… until it doesn’t. 🙁 Conway, if using a 36″ drogue is what you believe will work, I bet it does. At your L3 weight, man, go with your gut. 8)
Ken Plattner
Bruce, if you are going to tap the 4/40’s use a No. 43 drill. Or use a 3/32 without (taken from my old Sunstrand Machinist Handbook). Try them on some scrap pieces first though.
Ken.
Warren B. Musselman
For birds 4″ dia and below, I use 2-56 nylon screws. I use 4-40 on some 4″ birds and above.
2-56
Clearance Hole = 3/32″
Tap Hole = 5/64″4-40
Clearance Hole = 1/8″
Tap Hole = 3/32″Warren
Bruce R. Schaefer
Doug Gerrard
Conway Stevens
Ken Plattner
Warren B. Musselman- You must be logged in to reply to this topic.