Rsim for Art Applewhite Saucer

[seo]

Has anyone done a Rsim for an 18mm Art Applewhite saucer? I would like to try simulate but I am stuck on how to do the saucer body portion.

Another question, has anyone attempted to CHAD stage one of these saucers?

Scott

 

[Fore Check]

Originally posted by seo
Has anyone done a Rsim for an 18mm Art Applewhite saucer? I would like to try simulate but I am stuck on how to do the saucer body portion.

Another question, has anyone attempted to CHAD stage one of these saucers?

Scott

I haven't built nor seen a rocksim file for any saucer.

I do know, however, that CHAD staging of other saucers works very well. The aerodynamic stability of an Applewhite saucer can't be significantly different - I would not be scared at all to try it.

 

[rstaff3]

I built a Rsim file for a saucer at one time but can't find it. Unless someone knows how to fake base drag in Rsim there likely isn't any point. My standard flight for the Snitch is a D12-0 CHAD staged to a C0-0 (spent casing). I agree with ForeCheck that it will most likely work with an Art Applewhite saucer.

 

[seo]

Thanks Fore Check and Rstaff3-

That was my gut feeling that the Chad should work fine. Thanks for the sanity check.

 

[Rick James]

I don't know where I got this, but it is in my design file... if it helps great! if not, oh well - my post count is up one

 

[teflonrocketry1]

Attached is an unproven and unverified RockSim version 5 simulation for an Art Applewhite 18mm delta flying saucer (6 inch diameter).

Bruce S. Levison, NAR #69055

 

[seo]

Thanks for both of the rocksim files. I have a 18mm delta which I haven't built yet, so that file will be useful also.

I'll let you know if the Rsim predicts close to actual results.

Thanks

Scott

 

[Stymye]

that rocsim can't be right
the cp of a pure cone is always approx 2/3 from the tip twords the base.

 

[rstaff3]

I didn't look at the Rsim but if its a standard saucer there will be airflow through the middle and the spars/fins would have some effect, as would some base drag effects. That being said, I still don't really think Rsim will be accurate in this case.

 

[teflonrocketry1]

Originally posted by stymye
that rocsim can't be right
the cp of a pure cone is always approx 2/3 from the tip twords the base.

Stymye

That is true about the static CP of a conical shape. For this simulation to be accurate, you have to take into account the effects of base drag on the CP once this flying saucer shaped rocket is in motion. This is why the conical transition to bring the CP aft was incorporated into the simulation. This same approximation works good for spool rockets which also have much less than a 10:1 length to diameter ratio. It also explains why and Estes Fat boy is stable with apparently less than a one caliber margin of stability. If you take into account the base drag forces from dynamic motion the CP will mover further aft to give a higher stability margin.

Bruce S. Levison, NAR #69055

 

[rstaff3]

I may have to retract my statement that I wouldn't believe the sim. I forgot to take into account he author

It will be interesting to compare actual to estimated altitude.

 

[Stymye]

makes sense now , you're sort of "enhancing" the cd and base drag that rocksim calculates during the flight...too bad you can't adjust the parameters manualy...thanks tef