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Old 08-31-2014, 11:39 AM
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Join Date: Aug 2014
Posts: 7

Yeah, the commercially available VPP setups are just too small for this project. According to E-flight the VPP's are "3D CAD engineered for use on 3D models weighing up to 12 ounces (340 g) ready to fly (including VPP system)" That isn't going to cut it for this model and I doubt the chinese clones will fare better. I'm expecting an AUW of near 12 lbs depending on battery selection and some of the final details of this setup.

The inspiration to use tail rotor as an aircraft's constant speed prop came from this guy's youtube video ( He only uses two blades and they are the stock tail rotor blades, but mechanically the idea is basically the same.

So basically, from everyone's input I'm narrowing it down to two paths:

Path 1: 600+ size 3-blade tail rotor
PROS: requires minimal modification for implementation
CONS: appear to be impossible to find at a non-prohibitive price

Path 2: 450 size 3-blade main rotor
PROS: easier to find and less expensive
CONS: requires more significant modifications to use (eliminate cyclic movement and isolate collective)

Given how mechanically straight forward it is (from a conceptual basis), I'm kind of surprised that a company hasn't made a variable pitch prop for the non-3D scale fliers out there.

As of right now, I'm leaning towards Path #2 using an inexpensive 450 side main rotor, specifically the unit pictured below. At $20 I'm sure it's not great quality but the price is amiable to experimentation.

I'd still need to find the axle diameter but maybe if I switch to a geared setup, it will afford me some flexibility in hub/motor pairing. Basically from there, I'd remove the swash plate and replace it with a 3-pronged version of the component pictured below (if I can find one... otherwise I may be looking at fabrication, but conceptually the piece looks mechanically straight forward)

I appreciate all of your thoughts, suggestions and input and continue to look forward to your advice going forward. It should be a pretty slick setup once it's implemented! ...I hope!
njherr is offline  
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