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Old 05-06-2005, 04:20 PM
six-o-one six-o-one is offline
Craftsman
 
Join Date: Mar 2005
Location: collierville, tn
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Default "D" conversion and plastic/balsa NC question

Couple minor questions if anyone has any input for me. First, upon retrieval and repair of the tree'ed Cherokee D, I replaced the balsa NC with the plastic version (as the balsa one is still in the tree). Will this create a stibility issue? There is no notation in the plans for the original plastic NC version about addition of weight. Just doing an approximate CG/CP it seems OK, but there has to be a weight distribution difference. Oh well, any thoughts on the subject are appreciated.
Secondly. Finishing up my Estes Vigilante 2-stage clone. Used a CC-Express for both stage BTs, with just a minor cutting down of the booster to correct size. The Vigilante is a C-toC motor setup. The CC Expresss came with D motor mounts. Wondering if I could make me a D motor booster just like the one I have, so I could use both. Would the additional thrust overpower the 3/32 fin stock, or would it be OK as long as I still have a good CG/CP relationship?
Thanks for any input.
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Old 05-06-2005, 06:07 PM
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CPMcGraw CPMcGraw is offline
BARCLONE Rocketry
 
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Location: Mobile, Alabama
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Quote:
Originally Posted by six-o-one
Couple minor questions if anyone has any input for me. First, upon retrieval and repair of the tree'ed Cherokee D, I replaced the balsa NC with the plastic version (as the balsa one is still in the tree). Will this create a stibility issue? There is no notation in the plans for the original plastic NC version about addition of weight. Just doing an approximate CG/CP it seems OK, but there has to be a weight distribution difference. Oh well, any thoughts on the subject are appreciated.
Secondly. Finishing up my Estes Vigilante 2-stage clone. Used a CC-Express for both stage BTs, with just a minor cutting down of the booster to correct size. The Vigilante is a C-toC motor setup. The CC Expresss came with D motor mounts. Wondering if I could make me a D motor booster just like the one I have, so I could use both. Would the additional thrust overpower the 3/32 fin stock, or would it be OK as long as I still have a good CG/CP relationship?
Thanks for any input.


I have cloned the short-body Cherokee-D with the plastic NC, and it flies great. Keep in mind, Estes' designs have traditionally been over-stable to compensate for not-so-accurate building skills. The slight weight difference shouldn't change the CG enough to de-stabilize the model.

When Estes released the #1247 version of the Cherokee-D, they lengthened the body tube to a full 18" BT-55. This obviously helped make the rocket even more stable, but I think it was more of a simplification of the parts list than a concern for stability.

You should be fine with the D mount from the C-C Express booster. I would suggest venting the booster, and taking a little extra care when attaching the fins, but beyond that you should be fine. If you're in doubt, go look at the #1955 Ranger. This is a "D" bird that uses the Vigilante's fin sheet.


Craig McGraw
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Old 05-09-2005, 11:47 AM
six-o-one six-o-one is offline
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Location: collierville, tn
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Craig,
Well, that covers me. I appreciate the time and info. Wondered about what I had heard about the lengthened Cherokee D version, so that clears that up. Thanks again.

Rob
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