[SS-VehDev] Fwd: [ROC-CHAT] Ablative nose cone - not

[Lakestake Rocketry]

A cross post on a similar topic to what we are up against.

I have a couple of friends planning 100k flights this month on
AP.

Matt

---------- Forwarded message ----------
From: Bill <>
Date: Sep 6, 2005 6:32 PM
Subject: Re: [ROC-CHAT] Ablative nose cone - not

I've gone Mach 2 with a 1.5" LOC nosecone -- those things are strong, but 
that DID blister the clear coat on the nosecone and fins.

Went to Mach 2 once with an off-the-shelf fiberglass conical nosecone, over 
Mach for 10 seconds. Nosecone landed intact but crushed like an eggshell 
when I went to pick it up.

I've had no problems yet with conical nosecones I have built myself from 
carbon cloth and Aeropoxy. After cure, I bake the laminated nosecone in an 
oven at 350F for a few minutes (got that idea from Kurt G.). Then I saw off 
the end, drill and tap the plugged forward end of the nosecone and insert a 
piece of 3/8" threaded rod (usually aluminum). I build up around the rod 
with strands of carbon fiber and JB Weld until it is larger then the conical 
profile, then sand it to shape with a belt sander. The finished product is 
needle sharp, metal blending into composite. I paint it with some 1000F 
paint from McMaster Carr. Time consuming, but low tech.

I haven't destroyed one of those yet, but I'll keep trying -- even 
lake-staked one into the playa with no damage. On a 'fast' I600 flight I did 
last month (5 oz. min ID rocket), one layer of composite melted off from the 
fins, but the nosecone showed no sign of wear.

BTW, as I recall, NASA decided that the ablative coating on the X-15 was a 
big mistake -- it opaqued the pilot's windows.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.exrocketry.net/pipermail/ss-vehdev/attachments/20050906/6489de2e/attachment.htm