Min Velocity for stable flight

Min Velocity for stable flight

Post by Damian Burri » Tue, 03 Apr 2001 01:07:40



What is the min velocity for stable flight.  I thought I'd seen some where
it was 33ft/sec but rocksim 4 defaults to 43.999 ft/sec

Damian

 
 
 

Min Velocity for stable flight

Post by Jim Z in V » Tue, 03 Apr 2001 07:06:27


 > What is the min velocity for stable flight.  I thought I'd seen some
where

Quote:
> it was 33ft/sec but rocksim 4 defaults to 43.999 ft/sec

        Depends on wind conditions. In dead calm I've had stable flights
that were definitely under 30'/sec. And I've seen normally stable rockets go
sideways if hit with an unexpected gust. I think RockSim is erring on the
conservative side, maybe intentionally. I design for 35'/sec., and if I want
to try a motor that will be slower off the rod than that I wait for those
dead calm evenings.
--
Jim Z in Vermont
"As soon as you're born you start dying, so you might as well have a good
time."

             - Cake

(to reply by e-mail, remove the polite decline from my address)

 
 
 

Min Velocity for stable flight

Post by Jerry Irvi » Tue, 03 Apr 2001 09:31:27



Quote:


>  > What is the min velocity for stable flight.  I thought I'd seen some
> where
> > it was 33ft/sec but rocksim 4 defaults to 43.999 ft/sec

>         Depends on wind conditions. In dead calm I've had stable flights
> that were definitely under 30'/sec. And I've seen normally stable rockets go
> sideways if hit with an unexpected gust. I think RockSim is erring on the
> conservative side, maybe intentionally. I design for 35'/sec., and if I want
> to try a motor that will be slower off the rod than that I wait for those
> dead calm evenings.
> --
> Jim Z in Vermont
> "As soon as you're born you start dying, so you might as well have a good
> time."

>              - Cake

> (to reply by e-mail, remove the polite decline from my address)

Hi Gary Rosenfield...

I have a story to tell.  Everybody pull up around the campfire.

Gary Rosenfield used to need alot of rockets to "test" motors in . I was
all to willing to volunteer as any good rocketeer should.  Keep in mind it
is well known in advance the rocket is at risk and expendable.  (He once
confettied a perfectly good Enerjet Athena that way.)

I had this one rocket called the Hi-Test 2420 made (of course) from an ACE
tube and nose cone and fins of a custom shape.

The rocket was flown from a rack with 1/8" launch rod with probably a 3/16" lug.

The motor was an "E5" which was the precursor to the E6 and had a much
lower initial thrust spike or RAT.

The motor was ignited with Thermalite and was flown IIRC at Smoke Creek.

The rocket flew EXACTLY vertically and this motor was no more than 3:1 MAX
dropping down to under 1.5:1 during systain (for 9 seconds).

The motor worked perfectly and later made history and legends with a
continuous availability to this date of the E6 it spawned.

[campfire off]

Jerry

--
Jerry Irvine, Box 1242, Claremont, California USA

Bring common sense back to rocketry administration.

 
 
 

Min Velocity for stable flight

Post by Gene Costanz » Tue, 03 Apr 2001 12:56:06


Quote:

>...but rocksim 4 defaults to 43.999 ft/sec

> Damian

Damian, this fps value is the same as 30 MPH, a number bandied about as
a minimum for stable flight, but 30-35fps should be a safe minimum with
minimal to no winds.
--

METRA   BOD     TRA #07017 L2? NAR #74503 L2?

******************************************************************

There is no armour against Fate;  
  Death lays his icy hand on kings.