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Old 04-18-2009, 12:04 AM
MDorffler MDorffler is offline
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Join Date: Apr 2009
Location: Canon City, CO
Posts: 100
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Quote:
Originally Posted by James Pierson
Hi Mike,
thanks for all of your wonderful work for so many years with Estes and for taking the time to answer some questions.

My first question has to do with R&D and general designing of rockets. What are your procedures for test flying a design and in particular how are you checking for chute deployment?

Also in the same lines, can you give us some (any) tips on how to correct a design that is already built that has deployment problems? Sometimes it would be nice to have a C6-4!

How many times have you had a design that looked great and had to completely re-design the thing or just start over?

Are you folks using RockSim or other rocket design programs or are you just doing the math?

PS.
If Shrox falls asleep on the job do this. Get one of the Ping Pong balls off his desk and cut a hole in it and then hold it under his nose. That smell would wake up the dead, trust me some thinks Ive learn the hard way .

Thanks for your time, JP.
James Pierson
NAR# 77907


James, nothing personal, but I have never had any need to use 'model rocket design software' to design my model rocket kits. Never. Ask yourself what software I would have used in 1968, or 1973, or even 1990? I have always designed all my models using my natural skills. Normally I conceive a design totally in my mind driving either to or from Estes. That's the truth. I can tell you whether a model will be stable by simply looking at it, or hefting it, or whether it needs a pinch of clay in the nose to correct any CP/CG imbalance.

I do use CAD to create all necesary parts in 3D. It is a real treat to see the first sample parts come to you that look precisely as you drew them. And I also use CAD to lay out the kit, also in 3D, for the sole purpose of matching up the fit tolerances.

I always build several flight test versions of any new design. The first test round is with parts from inventaory, then with parts from pre-productions. I build the first test model with all the parts in positions as if built by a serious and carefull modeler. The next are built as though the the modeler is clumsey. Any flight of any test model has to be arodynamically stable, even when parts are glued on crooked. Only when I am totally satisfied that all of these versions fly absolutely straight, do I release it for the next production steps.
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