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  #11  
Old 08-04-2014, 12:27 PM
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Can't let a Cherokee-D thread go without adding something. The 18" version is the *right* length to me, perhaps since that was the length of my first one "back in the day". I've built both, but my upscales are based on the long version. Agree about nose weight, a D12-7 on the short version w/ Balsa NC needs a large steel washer to be stable. My most recent clone was a BT55 18" tube, with a 29mm mount for the Estes F15. Needed to entirely fill the plastic NC with clay, but flies great!
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  #12  
Old 08-04-2014, 12:46 PM
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Wow.
A 29mm F15 in a Cherokee-D.
Wonder if it goes any higher than one powered by an Aerotech E15/E30 as the motor weighs a lot more and so would the rocket due to all the clay in the nose. I'm thinking all that weight would offset the extra ~10n-sec of total impulse the F15 has over the E15/E30.

I always have at least one 18" Cherokee-D in my fleet.
The last one that I LOST was on either an E9-6 or E9-8. Winds were very low at ground level but were NOT at apogee ejection height.
A 12" chute was way too much for the winds up at around 2500'...should have used a long streamer instead. I think I lost that one in like 2007 or 2008.
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  #13  
Old 08-04-2014, 05:00 PM
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Quote:
Originally Posted by PaulK
Can't let a Cherokee-D thread go without adding something. The 18" version is the *right* length to me, perhaps since that was the length of my first one "back in the day". I've built both, but my upscales are based on the long version. Agree about nose weight, a D12-7 on the short version w/ Balsa NC needs a large steel washer to be stable. My most recent clone was a BT55 18" tube, with a 29mm mount for the Estes F15. Needed to entirely fill the plastic NC with clay, but flies great!
Funny, because my first one was the short version, that is the one that is *right* for me.

When I built the upscale using Semroc 225 tubing (OD is 2.43) the calculated length for the short version came out to 29.985" and Semroc had a 30" tube.

I did not remove .015" from the tube.
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  #14  
Old 08-04-2014, 05:44 PM
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Quote:
Originally Posted by ghrocketman
Wow.
A 29mm F15 in a Cherokee-D.
Wonder if it goes any higher than one powered by an Aerotech E15/E30 as the motor weighs a lot more and so would the rocket due to all the clay in the nose. I'm thinking all that weight would offset the extra ~10n-sec of total impulse the F15 has over the E15/E30.

I always have at least one 18" Cherokee-D in my fleet.
The last one that I LOST was on either an E9-6 or E9-8. Winds were very low at ground level but were NOT at apogee ejection height.
A 12" chute was way too much for the winds up at around 2500'...should have used a long streamer instead. I think I lost that one in like 2007 or 2008.


+1 to the streamer concept. I'm going to making the fins from basswood, so a 48" streamer should be plenty.
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  #15  
Old 08-04-2014, 08:33 PM
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Quote:
Originally Posted by ghrocketman
Wow.
A 29mm F15 in a Cherokee-D.
Wonder if it goes any higher than one powered by an Aerotech E15/E30 as the motor weighs a lot more and so would the rocket due to all the clay in the nose. I'm thinking all that weight would offset the extra ~10n-sec of total impulse the F15 has over the E15/E30.

I always have at least one 18" Cherokee-D in my fleet.
The last one that I LOST was on either an E9-6 or E9-8. Winds were very low at ground level but were NOT at apogee ejection height.
A 12" chute was way too much for the winds up at around 2500'...should have used a long streamer instead. I think I lost that one in like 2007 or 2008.


Not much higher - A quick 'n dirty sim, ignoring the lack of ideal delay times, says:

1160' for a D12
1780' for an E9
2120' for an E30
2340' for an E15
2470' for an F15 (with the additional 2 oz nose weight)

YMMV. I have no idea how high it actually went, other than out-o-sight. The long burn, though, is great fun! I was lucky to recover it after the first flight, and don't expect to next time...
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