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  #21  
Old 01-24-2009, 01:52 AM
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Mark II Mark II is offline
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I have a Cherokee-D parts pack that I bought from Thrustline, back when it was still up and running, and I have decals from Excelsior. I'm reluctant to open up the kit now. I may do a clone of it myself instead. (Not logical, I know.)

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  #22  
Old 01-24-2009, 07:29 AM
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Quote:
Originally Posted by LeeR
It is the same length, I checked my PNC-55AC earlier. Lots of good info in all the replies here. I didn't think to check that the Bullpup uses the same PNC-55AC as the later CD. I scrounged one out of the parts box, and sure enough, I've got one. I was trying to decide if I would cut down an 18" tube, and then saw this info on the later version using the 18" tube.

Oddly enough, when you load the #1247 plan, it has the K-47 plan pages shown, with the #1247 plans appended at the end.

I've had the decals for a couple years, so this has moved to the "build now" list. I never built one when they were in production. I'm testing out the production runs of my Fin Wizard to make absolutely sure all the body tube sizes are OK -- the prototype table was only a BT-50 model, so I've got a couple sizes yet to test.

I did make the fins out of basswood, and then decided to taper the fins. These are a pain, since you've got to sand everything but the root edge. No knife edge aggressive tapers on these, they are only gently rounded.


The best starting point for a Cherokee-D these days, if you're going to build a PNC version, is the C-C Express. I have not seen an official 2009 kit list from Estes, but it was still shown in the 2008 catalog. CCX has the PNC-55AC, a full BT-55, and most of the parts for the "D" mount.
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  #23  
Old 01-24-2009, 11:02 AM
GIJoe GIJoe is offline
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Quote:
Originally Posted by LeeR
It is the same length, I checked my PNC-55AC earlier. Lots of good info in all the replies here. I didn't think to check that the Bullpup uses the same PNC-55AC as the later CD. I scrounged one out of the parts box, and sure enough, I've got one. I was trying to decide if I would cut down an 18" tube, and then saw this info on the later version using the 18" tube.


I measured my Bull Pup PNC-55AC against an Estes BNC-55AC. I got a .25" difference. I only have the one balsa NC so I am not sure if the variation is there. I also have a set of Original Decals to use on my clone. As soon as the weather warms up, I will finish it off. Had I known the original was marginal, I would have lengthen the BT, guess I am stuck now with adding a little nose weight.

Joe
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  #24  
Old 01-24-2009, 11:13 AM
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IMHO, the shorter body tube Cherokee-D looks better than the 18" BT version. I've had no stability issues with short version Cherokees from the original up to 4" diameter on "J" EX motors. If you are a little worried about stable flight, just check the CP/CG and add a little nose weight if needed. I've never had to.
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  #25  
Old 01-24-2009, 01:40 PM
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Quote:
Originally Posted by GIJoe
I measured the Fin Blanks from my Semroc fins and come out with these figures:

3 3/4" for the Root Edge
2 1/2" for the Leading Edge
2 7/32" for the Fin Tip
2 5/32" for the Trailing Edge

These measurements are taken as if the Fin Tip wasn't rounded off into the Leading Edge and the Trailing Edge.

Joe

I still have the fin pattern from my original Cherokee from the 70s. Measuring "to the sharps" I get the following:

3.75" (95 mm) for the Root Edge
2.5" (64 mm) for the Leading Edge
2.20" (55.5 mm) for the Fin Tip
2 .18" (55 mm) for the Trailing Edge

The pattern must have been made for 3" balsa, as it is a two-piece fin. I scanned it 100% into a PDF (the 1" grids in the background did not show up so well in the BW scan, so I made a grey scale scan too).

My original "short tube" flew fine, and I cloned that version.

EDIT: here is RS sim image
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File Type: pdf CherokeeD_FinPattern_GS.pdf (135.3 KB, 78 views)
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  #26  
Old 01-24-2009, 01:41 PM
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Quote:
Originally Posted by GIJoe
I measured my Bull Pup PNC-55AC against an Estes BNC-55AC. I got a .25" difference. I only have the one balsa NC so I am not sure if the variation is there. I also have a set of Original Decals to use on my clone. As soon as the weather warms up, I will finish it off. Had I known the original was marginal, I would have lengthen the BT, guess I am stuck now with adding a little nose weight.

Joe


I measured the plastic version, and it was exactly the length given in the BMS catalog for their balsa clone. I have had variations in really old Estes cones, so that might explain your difference. With this one being so pointy, that could be the reason -- easy to lose a 1/4" of a long pointed cone.

I visited Estes in 1966, and remember seeing their nose cone machine. I recall taking pictures, but I've only found a few, and none of that machine. I seem to recall the lathe feeding in really long blocks of balsa. I also seem to recall they had a rack of grinding stones, but do not recall the "turning" method. The grinding stone may have given the profile, and maybe a cutter completed the shoulder. I do remember them getting cut off, dropping into a box, and the next cone getting started, all pretty automated.

I'd love to know if anyone has pictures of some of those old Estes machines. I also remember seeing Mabel make engines, and the contraptions for making igniters, and wadding from TP (not sure if it was Charmin, or Northern, or maybe Scott? ...)
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  #27  
Old 01-24-2009, 07:58 PM
GIJoe GIJoe is offline
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I remeasured both my nose cones, being a bit more accurate this time. I am about 1/16" of an inch short on my Balsa cone and 1/16" long on my plastic Nose Cone. The 1974 Catalog reports the length at 5 3/8" so I would have to agree with that assessment.

Joe
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  #28  
Old 01-27-2009, 12:49 PM
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I'm looking to clone about 6 or 7 rockets, some don't have the thickness of the balsa sheets on some. I may have missed it somewhere too, trying to get a list together back and forth from home and work.

What are the average thickness of fins on Estes kits? 3/32, 1/8, 3/16? I'm gonna say normal A,B,C, small D's. The larger rockets like the D-Region I think is 3/16, been forever since I replaced the fin. Or am I 1/16 large on that? This will give me a ballpark figure of what I am looking at.

Thanks guys
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  #29  
Old 01-27-2009, 01:14 PM
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Quote:
Originally Posted by Davidtmp
I'm looking to clone about 6 or 7 rockets, some don't have the thickness of the balsa sheets on some. I may have missed it somewhere too, trying to get a list together back and forth from home and work.

What are the average thickness of fins on Estes kits? 3/32, 1/8, 3/16? I'm gonna say normal A,B,C, small D's. The larger rockets like the D-Region I think is 3/16, been forever since I replaced the fin. Or am I 1/16 large on that? This will give me a ballpark figure of what I am looking at.

Thanks guys


BFS-10 = 1/32"
BFS-20 = 1/16"
BFS-30 = 3/32"
BFS-40 = 1/8"
BFS-50 = 5/32"
BFS-60 = 3/16"
BFS-70 = 7/32"
BFS-80 = 1/4"

The Cherokee-D used BFS-40.
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  #30  
Old 01-27-2009, 01:35 PM
Davidtmp Davidtmp is offline
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Craig,
OK, looking at Willie Logans page on discontinued parts, I see that the balsa sheets on the Orbital transport are BFS-20L which looks to be a long piece of Balsa. On the A-20 Demon the balsa sheet lists BF-58. So does this mean it is actually a 5/32" balsa sheet, with the last number representing the length of the sheet Estes used(maybe 8")? So really we look at the first number and see what range that is in to determine the thickness.
Am I on the right page??
Nice work you guys have done on the cloning sheets, helps a great deal.
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