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-   -   A.S.P. fin thickness? (http://www.oldrocketforum.com/showthread.php?t=7375)

blackshire 07-14-2010 05:56 AM

A.S.P. fin thickness?
 
Hello All,

(Before I ask my question about the Estes A.S.P. Semi-Scale kit below, take a gander at Chris Timm's "UK missile pics" thread on this forum section!)

Now to my question: I was just looking at the mini-motor powered Estes A.S.P. Semi-Scale kit (Cat. No. #0862, see: http://www.ninfinger.org/rockets/ca...82/82est26.html ). The plans are online here: ( www.spacemodeling.org/JimZ/est0862.htm and www.spacemodeling.org/JimZ/estes/est0862.pdf ).

What thickness of sheet balsa (1/16", 1/8", or 3/32") did it use for its fins? (John Brohm's Body Tube/Kit Index says that it used an 18" length of BT-20 for its body tube, and it had a BNC-20N balsa nose cone, for which the PNC-20A nose cone in the Wizard and Viking kits is a plastic direct replacement.) The Estes A.S.P. would make a nice "fun scale" kitbashing project.

Many thanks in advance to anyone who can help.

CPMcGraw 07-14-2010 08:01 AM

Quote:
Originally Posted by blackshire
Hello All,

(Before I ask my question about the Estes A.S.P. Semi-Scale kit below, take a gander at Chris Timm's "UK missile pics" thread on this forum section!)

Now to my question: I was just looking at the mini-motor powered Estes A.S.P. Semi-Scale kit (Cat. No. #0862, see: http://www.ninfinger.org/rockets/ca...82/82est26.html ). The plans are online here: ( www.spacemodeling.org/JimZ/est0862.htm and www.spacemodeling.org/JimZ/estes/est0862.pdf ).

What thickness of sheet balsa (1/16", 1/8", or 3/32") did it use for its fins? (John Brohm's Body Tube/Kit Index says that it used an 18" length of BT-20 for its body tube, and it had a BNC-20N balsa nose cone, for which the PNC-20A nose cone in the Wizard and Viking kits is a plastic direct replacement.) The Estes A.S.P. would make a nice "fun scale" kitbashing project.

Many thanks in advance to anyone who can help.


I think we've touched on the ASP fins somewhere on this forum, but it's been a couple of years ago...

Using the 1974 Parts Catalog as a guide, the part number for the fin sheet is 32257, which falls between the fin sheets for the HoJo (32256) and the TEROS (32258). Both of these sheets were 3/32" [BFS-30].

Using the first page of the plans as a guide, however, you would be inclined to think 1/16" [BFS-20]. These fins have a paper (cardstock) tab attached on the bottom edge, and the thicknesses for both seem to be drawn proportionally to each other.

If I were to build a clone today, I'd stick with BFS-20. Estes did not seem constrained to keep part numbers entirely consistent, so following with the Parts Catalog numbers might not be the best way to go on this one. Only someone who has an original kit (built or NIB, Scigs30, you doing this one?) can say otherwise.

blackshire 07-14-2010 09:42 AM

Craig, I thank you for this information. I was inclined toward the 1/16" thick BFS-20 myself (that's what I used in my BT-5 size Nova Hobbies ASP kits (see: http://www.rocketreviews.com/review..._nova_asp.shtml ). 3/32" just seems too thick, including for how the Estes A.S.P.'s fins look in the kit card photograph.

For the larger BT-20 size Estes A.S.P., I'll probably "paper" the 1/16" thick fins for extra strength and to obviate the need for sanding & sealing (my same reason for using a plastic PNC-20A nose cone instead of a balsa BNC-20N nose cone). Unlike my ASP kit (which put on a fair imitation of the U.S.S. Enterprise's transporter [now you see it, now you don't!]), the larger Estes version should be slow enough (although probably *just*) that I can actually follow the powered portion of its ascent.

barone 07-14-2010 09:46 AM

1 Attachment(s)
I built a scale model of the A.S.P. for NARAM 49 so it wasn't exactly like the Estes kit but you might be able to use these ideas.

I used 1/16" balsa. Attaching the fin tabs is a pain and they usually get taken off in the first flight. The scale data shows the tabs on a side of the fin and not centered on the bottom. So, I made card stock overlays of the fin and tab to go on one side of the fin and just a fin for the other side. If you plan on attaching flares to the fin tips, the overlay helps to keep them secure (I had one break off on landing but it was an altitude event and I used a streamer instead of going with a small parachute).

I used ST-7 tubing and nose cone from Semroc. I cut the tip of the nose cone off to install the antennae and then used squadron putty to re-build and shape the nose cone around it. You can use the extra weight because it's initially a little unstable on a C motor but straightens out and flys straight. Fin tabs create quite a bit of spin..... ;)

Anyway, here's a picture of it........

blackshire 07-14-2010 10:51 AM

Don, thank you for posting the photograph and description! I'll stick to the "stock" Estes A.S.P. for now. I noticed, though, that Semroc has what they call "Deci-Scale" (1/10th Scale) 5:1 tangent ogive ASP nose cones and conical (11 degrees, I believe) Nike-ASP nose cones on their web site. Maybe kits incorporating these will follow soon?

sandman 07-14-2010 01:41 PM

I just finished the decals for the ASP.

ghrocketman 07-14-2010 02:14 PM

The fins on the Estes ASP kit were NOT balsa of any thickness.
I built an original MANY years ago that I still have.
They were fibreboard like Centuri used in many of their kits including all the Super Kits.

blackshire 07-14-2010 05:25 PM

Quote:
Originally Posted by ghrocketman
The fins on the Estes ASP kit were NOT balsa of any thickness.
I built an original MANY years ago that I still have.
They were fibreboard like Centuri used in many of their kits including all the Super Kits.
That may have been a later production run of the kit, as the one on JimZ's web site definitely has balsa fins.

blackshire 07-14-2010 05:27 PM

Quote:
Originally Posted by sandman
I just finished the decals for the ASP.
Wow--thank you very much for the fast service! The PayPal payment has been sent.

CPMcGraw 07-14-2010 05:39 PM

Quote:
Originally Posted by blackshire
That may have been a later production run of the kit, as the one on JimZ's web site definitely has balsa fins.


And the plans specify a balsa sheet in the parts list.

But, that's a thought if someone was willing to try it -- a laser-cut set of matteboard fins, 0.02" thick. Carl's material is far superior to what Estes used in the past, so it might hold up longer once it's been sealed and painted.


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