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

[william colburn]

Very interesting post as it refers to actual
experience. All epoxies are similar in that they are
good in service to their cure temperature,
approximately. Of course curing at 1000 F doesn't
work!

The 1000 F paint is an ablative coating of sorts.

That is the way to do an NC tip: you make a conical
frustum  plug with a tapped hole which is inserted
into the NC which has been also truncated. This then
creates a flush surface for mounting the machined tip
with a short threaded stud. The cone is then captured
between the tip and the inner plug.

BC

--- Lakestake Rocketry <lakestake at gmail.com> wrote:

> 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.
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