Brant
These are all good questions - but none of them have perfect answers. What seems reasonable to me is to pick a prop that others are having success with, set it to around 1.5:1 P/D ( or around 10 pitch), start with 3/32" rubber and then adjust the variables until you get the best performance.
The cop-out answer to your question about optimal pitch:
Optimal pitch is the one that gives you the highest flight time.
If your higher pitch prop requires more torque to reach the ceiling, that is not on it's own a bad thing. Launching with more torque means launching with more turns - assuming you're talking about more torque in the same size motor. This is always one of the goals in getting longer flight times. How does your model with the high pitch prop do in the cruise and descent phases? These are the parts of the flight envelope where you want to rack up time. If you increase the prop pitch too much, then the cruise torque required is going to be too high and your times will suffer.
Adjust the cruise first. Get the best combination of prop pitch and model trim for the cruise. Then go for the ceiling height with launch torque adjustments. This is a simple procedure that will get you to probably 90% of the best you can do. You'll be flying better than most everyone at that point. The last 10% will require advice from people with names like Kagan, Brown, Calliau, etc.
----- Original Message -----
From: Brant Fredrickson
To: Indoor_Construction_at_yahoogroups.com
Sent: Wednesday, November 29, 2006 8:33 AM
Subject: [Indoor_Construction] Re:prop pitch
A veteran flyer once told us to watch how the model flies and increase or
decrease the pitch accordingly. Unfortunately we didn't ask what we should
look for in the model's flight. We have noticed when the pitch is way too
high the model won't climb and if it is a little too high, it takes a higher
torque to reach the ceiling. Is the optimal pitch is the one that takes the
lowest torque to reach the ceiling?
Last year we stumbled onto a pitch that seem to work and optimized the
rubber width to that pitch. Did we have the process backward? Should we have
picked a rubber width for the ceiling height and then optimized the pitch to
the rubber width? As a beginner I certainly don't have the answers to these
questions.
www.BrantFredrickson.com
mailto:RealEstate_at_BrantFredrickson.com
Century 21 Homestar, Cleveland, Ohio
home office 440-442-5866
mobile 440-983-1173
fax 440-442-3678
[Non-text portions of this message have been removed]
Received on Wed Nov 29 2006 - 07:33:31 CET
This archive was generated by Yannick on Sat Dec 14 2019 - 19:13:44 CET