Rocksim or WRASP - Who do YOU think's right?

Rocksim or WRASP - Who do YOU think's right?

Post by J. Stuckma » Thu, 07 Jan 1999 04:00:00



What program is more accurate in altitude prodiction? If I run a wrasp
sim on the Loc Warlock on a J350, I get approx 1400'. Rocket is approx
100 oz. in sim. When I downloaded the Rocksim profile for the Warlock,
it says 2300+ feet for the same motor with the rocket at approx. 94 oz.
I temd to think the wrasp is closer to reality!

Jim Stuckman
--
NAR # 73264  *  Level 1
CATO Club Secretary (Tripoli SE Connecticut/NAR Section 581)
http://surf.to/stuckman  Surf to Stuckman! 13 Pages of Model Rocketry
**Want to Buy or Sell Rocketry Items? Monthly Auctions http://start.at/jims-auction
Visit Essence's Rocketry Reviews at http://dc.jones.com/~essence

 
 
 

Rocksim or WRASP - Who do YOU think's right?

Post by Shick » Fri, 08 Jan 1999 04:00:00


Jim
Check to make sure you are using the same co effeciant of drag for both
programs. That can make a big difference. If I remember right, Rocksim's stock
setting is a little lower.
mike

 
 
 

Rocksim or WRASP - Who do YOU think's right?

Post by Pete » Fri, 08 Jan 1999 04:00:00


-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Quote:

> What program is more accurate in altitude prodiction? If I run a wrasp
> sim on the Loc Warlock on a J350, I get approx 1400'. Rocket is approx
> 100 oz. in sim. When I downloaded the Rocksim profile for the Warlock,
> it says 2300+ feet for the same motor with the rocket at approx. 94 oz.
> I temd to think the wrasp is closer to reality!

> Jim Stuckman
> --
> NAR # 73264  *  Level 1
> CATO Club Secretary (Tripoli SE Connecticut/NAR Section 581)
> http://surf.to/stuckman  Surf to Stuckman! 13 Pages of Model Rocketry
> **Want to Buy or Sell Rocketry Items? Monthly Auctions http://start.at/jims-auction
> Visit Essence's Rocketry Reviews at http://dc.jones.com/~essence

        Hey Jim... You may or may not remember me... I bought the Estes RAMJET off
you...
    Anyway, I own rocksim also, and of course, I have WRASP as well. Both of these
programs have Drag
Coefficient, Air pressure, Air temperature, Height above sea level, and a few other
things (RocSim actually has a
variable for Latitude!) listed as variables, which you can change. I would compare
those variables, before comparing
the two program's abilities to assess and simulate a rocket's flight. (I for one, would
go with RocSim as the more
accurate program, since it is more advanced, and takes into account so many more
things, such as the shape of the
cross-section of the rocket's fins.)
    I would generally assume that the large difference in estimated altitude is due to
a diference in the environmental variables between the two programs you should check.

        -Peter Slow

  crazprsn.vcf
< 1K Download
 
 
 

Rocksim or WRASP - Who do YOU think's right?

Post by David Urbane » Fri, 08 Jan 1999 04:00:00


Quote:

>> What program is more accurate in altitude prodiction? If I run a
>> wrasp sim on the Loc Warlock on a J350, I get approx 1400'.

wrasp, as far as I can tell, uses a constant Coefficient of Drag (Cd).
Rocksim's varies with velocity which is closer to reality.  I think
Rocksim is more accurate.

I say this because the Wrasp sim on my Mustang showed an F50-10 was
almost a perfect delay time.  Rocksim showed it was about 2 seconds too
long.  The flight agreed with Rocksim.  It was only my second flight
with my Mustang and it scared the heck out of me when I expected an
apogee ejection and got one 2 seconds or so after the fact.

At the time I would have sworn it took 4 or 5 seconds, but the instant
replay via video camera proved that emotional state can greatly alter
time sense.
--
=====================================================================
"The world is full of thorns and thistles. It's all in how you grasp
them." -- Arnold Glasgow

David Urbanek  (NAR# 73974)
http://public.surfree.com/urbanek