Drogue chute sizing - Northern Colorado Rocketry

This topic has 12 replies, 3 voices, and was last updated 19 years, 2 months ago by Anonymous.

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August 4, 2006 at 10:43 pm #39703
Ken Plattner
Participant
Several simulators I’ve used on the net determine different sizes of drogues for a 110 oz rocket. Question is, do they consider the spill holes? For example, one simulator says to use a 24 In. chute, but no mention of a spill hole. Another says 36″ So, how much of a factor is the spill hole for a drogue? I know the rocket should descend at about 50’/sec under drogue.
August 4, 2006 at 11:00 pm #43151
Anonymous
FWIW, I’ve flown almost 200 HPR flights, and I’ve used drogue chutes exactly three times. I’ve used streamers for some pretty big projects, and the *vast* majority of my shots use nothing at all– I just break them at apogee.

I’d say for a rocket that weighed 4# or less, no drogue whatsoever is necessary. For one that weighs 4#-15#, a big honkin’ streamer works fine. Over 15# I tend to want to use some extra laundry 😉

To me, there is nothing– and I do mean NOTHING more cool than the sound of a 10′ streamer flapping in the wind on a calm morning up at the north site. If it is dead calm, the streamer sounds like a flag getting shredded in high winds. I love that!

Your 110 oz rocket would do great on a streamer. If the rocket is 3″ diameter or greater, I have a wonderful streamer that you may borrow if you want to go that route—
August 4, 2006 at 11:59 pm #43152
Conway Stevens
Participant
I to have done the streamers on my flights as well (some as high as 11 to 14k) as nothing but seperation and airdrag. But with my L3 im still trying to get an idea on a chute for the drouge myself. so for my application I planned on using a 36″ drouge chute (a Tac1 chute actually from Giant Leap) As that I am at 55lbs of weight. Im hoping my choice isnt to big but this will be my first real use of a drouge so I understand what you mean.(JW if ya want let me know if you think im to big on my choice) For the size you are flying I wouldnt recomend a drouge Just like John says use a streamer.. Trust me you will be happy. something that small on a drouge would possible if not probabbly drift a ways.
August 5, 2006 at 1:59 am #43153
Chris LaPanse
I use a Skyangle 20 for a drogue on my 14lb, 4 inch rocket, and I am planning on using a skyangle 36 on my upcoming 20-25lb project. Honestly, I would lean on the small side of those estimates, or even just use a streamer and you should be fine.
August 5, 2006 at 2:30 am #43154
Ken Plattner
Participant
JW, how big is your streamer? WxL? I wouldn’t want to impose, so I’ll either make one myself out of nylon (or my wife will!) or just buy one. No big deal. I’m more concerned about the decent speed than anything else. Last big one (for me anyway) I flew had a major zipper that I really don’t want to repeat.

Thanks.
August 5, 2006 at 3:26 am #43155
Conway Stevens
Participant
How long and what is the width of your shock cord? A shock cord thats to short can very easily cause a Zipper on dual deploy. I like my shock cords larger and longer. They take alot of the steam out of a deployment charge. Also what are you using for a altimeter? If programmed like the ARTS it may be deploying late or early.. if not using dual deploy another major factor can be a wrong choice in ejection time on a motor Ejection.
August 5, 2006 at 3:56 am #43156
Ken Plattner
Participant
My zipper was do to motor deployment. Too early or too late, I don’t know. Kind of weird, because one AT motor (10s) no issue, a bigger AT motor (10s), the big ZIP – probably moving too fast past apogee. My shock cords were about 5x the airframe length (20′ or so). Don’t remember, but I think they were 1/4″ or 3/8″ kevlar tube. For my new bird, both drogue and main will be RRC2 controlled. I like the idea of a streamer, but don’t really know how to size it to get to about 50’/sec descent rate.
August 5, 2006 at 5:37 am #43157
Chris LaPanse
In all honesty, I wouldn’t be that concerned about maintaining exactly 50ft/s. It’s perfectly fine to be above or below that by a considerable margin, and your rocket will work fine regardless. Just find a suitably large streamer, such as the 4″ by 144″ nylon one sold by PML, and you will be fine.
August 6, 2006 at 12:37 am #43158
Anonymous
JW, how big is your streamer? WxL? I wouldn’t want to impose, so I’ll either make one myself out of nylon (or my wife will!) or just buy one. No big deal. I’m more concerned about the decent speed than anything else. Last big one (for me anyway) I flew had a major zipper that I really don’t want to repeat.

Thanks.

My streamer is perhaps 8″ wide x 8′ long. You would not be imposing if you borrowed it. This streamer is quite heavy; I had it made. It is about the thickness of a potholder, if you know what I mean. It is bright silver. By my calculations it has about 300K of vertical travel so far :-O

This streamer is quite visible. It terminates in a triangular shape, and it has a gromet for quick link attachment. It is tight in a 3″ bird, but I fly it in a 3″ rocket all the time. It will indeed come out. ‘Tis not a problem to borrow for either your flight or to plagiarize. I’d be flattered…
August 6, 2006 at 2:56 am #43159
Ken Plattner
Participant
Thanks john. What is it made of?

Ken.
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