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Old Nov 19, 2014, 01:34 PM
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United States, CA, Monterey
Joined Jun 2010
126 Posts
Hi Tom that's great can you give a close up of the head? I think I have a set of AJ 450 blades. I would like to give it a try, did you use any tip weights? Its amazing you had success on the first try. Our weather is lousy at the moment so I have a bit of time to get one together again regards
Kevin
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Old Nov 19, 2014, 04:43 PM
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Joined Feb 2012
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Kevin the 0.8mm thick plate is 25 mm wide and 100 mm long ,the blade bolt holes are 35 mm from the plate center.
Taking in to account the up elevator needed the estamated rotor trim angle would be 9 -10 degrees with the elevator at zero.
This data applies to a model with an AUW in the range of 15-17oz .
The experiment would I think be best done with a dual axis head and the model initially flown with three blades , then if the three blade area can be achieved with two blades its a fair chance the model will fly with minimal trim adjustment required, (perhaps within 10% would be OK).
The model flown today was a first try and I cannot claim any of the parameters are optimal but the model flew very much the same as it did with the shorter three blade set, possibly a little more sensitive in roll.
The blades were not corrected other than each having the same weight, so further advantage might me gained by optimizing blade cog that doubles up as tip weight .
I got the impression that play in the servo and head could be more detrimental to spin up and best efficiency than it would with three blades.
I found a more power was needed to get the model away but after that the normal cruise setting was sufficient to maintain a steady and moderate speed .
Power off descents and high alpha were no problem , but it did take longer to achieve head speed in the near calm conditions.
Perhaps this is the wrong thread to discuss this if Mickey would prefer we took it over to the CF thread perhaps he could give us a nod.

Tom.
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Old Nov 19, 2014, 07:58 PM
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Joined Jun 2010
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Thanks Tom, duly noted, thanks for the info
Kevin
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