> How close to the ground will that F/G pyramid be when the ejection charge goes off on each
> of those recommended motors?
I asked because if the rocket only gets to 200 or 300 feet apogee, and with a
saucer/pyramid that is basically at motor burnout, then the rocket will descend very close
to the ground by the time motor ejection occurs. This can cause fires.
Fires are bad.
Very bad.
if you fly on a dry lakebed, then you may not be concerned about this (unless the rocket
is approaching your car when ejection occurs).
That is why on regular Model Rocket sized saucers (like the Centuri or Estes or Quest)
they use booster motors or on the newer versions from Flis they use either booster or
plugged motors.
Have you considered this hazard?
-Fred Shecter NAR 20117

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> "Fred Shecter" wrote in message
>> How close to the ground will that F/G pyramid be when the ejection charge goes
[quoted text clipped - 9 lines]
> www.sunward1.com
> email address on web site
Bob Kaplow - 28 Feb 2006 18:24 GMT
> I asked because if the rocket only gets to 200 or 300 feet apogee, and with a
> saucer/pyramid that is basically at motor burnout, then the rocket will descend very close
> to the ground by the time motor ejection occurs. This can cause fires.
Fred, the good news about these draggy rockets is that they quickly reach a
rather low terminal velocity, so they don't fall nearly as fast as a 3FNC
model. While a short delay may be three seconds too long, the rocket will
still be high enough up to eject safely. Now I wouldn't recommend the use of
a long or XL delay in a rocket like this...

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Bob Kaplow NAR # 18L >>> To reply, there's no internet on Mars (yet)! <<<
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S&T is becoming this decades Steve Weaver!
Fred Shecter - 28 Feb 2006 20:41 GMT
Yes, I knew that, but the tremendous delay afterburn lasts for a while after the ejection
charge has gone off.
Problems could include:
1) Motors ejecting and hitting the ground while hot or flaming (that should be prevented
in the design and flight prep).
2) rocket landing while the delay afterburn is still going like a blowtorch.
3) Ejection low enough that ejection "particles" (flaming bits) hit the ground.
I understand that saucers and their close cousins are a religious fanaticism for some, but
NOT setting fire to launch sites is also a religion for others.
-Fred Shecter NAR 20117

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"""Remove "zorch" from address (2 places) to reply.
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>> I asked because if the rocket only gets to 200 or 300 feet apogee, and with a
>> saucer/pyramid that is basically at motor burnout, then the rocket will descend very
[quoted text clipped - 6 lines]
> still be high enough up to eject safely. Now I wouldn't recommend the use of
> a long or XL delay in a rocket like this...
Angelo Castellano posting - 01 Mar 2006 05:38 GMT
"Fred Shecter" wrote in message..
> I asked because if the rocket only gets to 200 or 300 feet apogee, and with a
> saucer/pyramid that is basically at motor burnout, then the rocket will descend very close
> to the ground by the time motor ejection occurs. This can cause fires.
>
> Fires are bad.
Yes they are.
During testing, I didn't find any problems with a fire hazard. Both pyramid
kits are Level 4. As for dry areas, extra care should always be taken.
To add an extra degree of safety, I will add a small warning to the website for
both rockets and will mention the potential in kits as they are produced.
Angelo Castellano
Sunward Aerospace Group Limited
www.sunward1.com
email address on web site