Rocket engines

Rocket engines

Post by Steve Stee » Tue, 11 Oct 1994 06:34:09



Does anyone know how long rocket engines are good for?  I've had a model
rocket setup for about 8 years that I never put together. I was wondering
if the engines are still good (or could they cause any harm if ignited).
Could someone send me e-mail and let me know.

Thanks,

Steve

 
 
 

Rocket engines

Post by bill nels » Tue, 11 Oct 1994 07:55:38


:
: Does anyone know how long rocket engines are good for?  I've had a model
: rocket setup for about 8 years that I never put together. I was wondering
: if the engines are still good (or could they cause any harm if ignited).
: Could someone send me e-mail and let me know.

I have some motors from the late 60s, that still function fine. I suspect
that C.D. does also.

Bill

 
 
 

Rocket engines

Post by bill nels » Wed, 12 Oct 1994 14:49:40


: >
: > I have some motors from the late 60s, that still function fine. I suspect
: > that C.D. does also.
: >
:   The critical factor is: where did you keep them? If they were in an attic
: or garage I suspect they have heat damage. What happens is the solid fuel
: grain expands under heat and permanently presses the casings out. When
: cooled to normal, then grains contract but the cases don't - leaving a
: gap between case and grain. The instant the burn front reaches the case wall
: the rocket engine becomes a roman candle. The rest of the grain gets barfed
: out the front of the motor & you have a little bolide. Not to mention a
: roasted-out recovery system.
:
:   If you kept them in an air-conditioned bedroom or other controlled
: environment they may be fine.

I have stored them in my garage, under a bed, in a spare room etc. They are
all B or smaller, and I have never had a problem with any of them.  I have
encountered temperature cycling problems only on D motors - not on any that
are smaller.

:   You can probably test one by burying it nozzle-up so that the nozzle is
: flush with the surface & then static firing it. If it doesn't "shoot the
: moon" the rest should be OK.

As I stated, they work fine.  Of course, I am reluctant to use up such old
collector's items.

Bill

 
 
 

Rocket engines

Post by ThomasEdwardThackerJun.. » Wed, 12 Oct 1994 13:59:44


Quote:
> : Does anyone know how long rocket engines are good for?  I've had a model
> : rocket setup for about 8 years that I never put together. I was wondering
> : if the engines are still good (or could they cause any harm if ignited).
> : Could someone send me e-mail and let me know.

> I have some motors from the late 60s, that still function fine. I suspect
> that C.D. does also.

  The critical factor is: where did you keep them? If they were in an attic
or garage I suspect they have heat damage. What happens is the solid fuel
grain expands under heat and permanently presses the casings out. When
cooled to normal, then grains contract but the cases don't - leaving a
gap between case and grain. The instant the burn front reaches the case wall
the rocket engine becomes a roman candle. The rest of the grain gets barfed
out the front of the motor & you have a little bolide. Not to mention a
roasted-out recovery system.

  If you kept them in an air-conditioned bedroom or other controlled
environment they may be fine.

  You can probably test one by burying it nozzle-up so that the nozzle is
flush with the surface & then static firing it. If it doesn't "shoot the
moon" the rest should be OK.

 
 
 

Rocket engines

Post by denma.. » Wed, 12 Oct 1994 07:38:52


IT>> : Does anyone know how long rocket engines are good for?  I've had a model

IT>> : rocket setup for about 8 years that I never put together. I was wonderin
IT>> : if the engines are still good (or could they cause any harm if ignited).
IT>> : Could someone send me e-mail and let me know.
IT>>
IT>> I have some motors from the late 60s, that still function fine. I suspect
IT>> that C.D. does also.

I have rocket motors that are 32 years old, most work fine, but they
have been stored indoors

 
 
 

Rocket engines

Post by C. D. Tavar » Sun, 16 Oct 1994 03:49:15


Quote:


> : Does anyone know how long rocket engines are good for?  I've had a model
> : rocket setup for about 8 years that I never put together. I was wondering
> : if the engines are still good (or could they cause any harm if ignited).
> : Could someone send me e-mail and let me know.
> I have some motors from the late 60s, that still function fine. I suspect
> that C.D. does also.

Not that I intend to fire my collectors' items just to find out...!

If they're small (C or under) black powder motors, they're probably fine.
If they're C5-3's, they're probably even better than contemporary ones.  :-(
--


                              write today for my special Investors' Packet...

 
 
 

Rocket engines

Post by Mark Spie » Sun, 16 Oct 1994 14:07:48


This brings up a question I have been meaning to post for some time now.  
I have a really old propellant slug which is of questionable origin. I
don't know the exact formula, but I do know that it is HTPB/AP/AL based
chemstry. Anyway, the slug looks very much like a big pencil eraser. But,
where the grain is exposed to air, it has turned purple/blue.

What is going on here?

    ^    
   |U|     Mark C. Spiegl
   |S|     Motorola

  ~~U~~    

.

 
 
 

Rocket engines

Post by Doug Holvers » Tue, 18 Oct 1994 04:52:46


SS> Does anyone know how long rocket engines are good for?  I've had a model
SS> rocket setup for about 8 years that I never put together. I was wondering
SS> if the engines are still good (or could they cause any harm if ignited).
SS> Could someone send me e-mail and let me know.

I've launched some Estes engines of '76-'77 vintage this summer and they flew
as good as new.
-DGH-

 
 
 

Rocket engines

Post by Lee Re » Thu, 20 Oct 1994 08:45:03


: Does anyone know how long rocket engines are good for?  I've had a model
: rocket setup for about 8 years that I never put together. I was wondering
: if the engines are still good (or could they cause any harm if ignited).
: Could someone send me e-mail and let me know.

About two years ago I launched an old Estes Saros (built late 70s)
on Estes motors from 1969.  After doing this twice, I realized I
should quit flying the rocket before it pranged or a motor CATO'd it.

I did experiment with a few other motors I had, all very old (18-20
years).  The 18mm B's and C's worked fine, but the D's were terrible.
Must have been more susceptible to thermal cycling, because all
launches had "blow-by" where the ejection blew almost immediately.
One rocket went up perhaps 100 feet, and it's paint was bubbling
on the outside from excessive heat.  This was a BT-55 sized rocket,
so there was space between motor and body.  None of the cases
ruptured, they just burned incredibly hot.  These motors were stored
with the 18mm motors all their life, so perhaps 24mm sizes are less
stable than 18mm.  

--
         /\      Lee Reep         TRIPOLI ROCKY MOUNTAINS -- # 72
    /\  /~~\  /\   Fort Collins, Colorado                TRA 2007

__/____\____/___/~~\_____________________________________________

 
 
 

Rocket engines

Post by TEXAS10 » Sat, 10 Dec 1994 16:05:04



Quote:
(Steve Steele) writes:

Steve, I had a mid 70's estes 1/2a5-2 in attic storage for 15 years which
fired
perfectly, I would say try it & see what happens, if kept dry & clean, I
think
these motors have a fairly long storage life (or is it coincidence?).

  Texas1027

   DARS SEC#308