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Groen Bros./Georgia Tech/DARPA 'Heliplane'

CammNut

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Here is the latest Groen/DARPA Heliplane configuration. The proposed demonstrator is based on an Adam A700 very light jet. Air from the twin Williams FJ44 turbofans is ducted to the rotor tips, mixed with fuel and burned to drive the rotor for vertical take-off and landing (remember the Fairey Rotodyne). In forward flight, at speeds up to 400mph (they hope), the rotor would autorotate like an autogyro. The notional mission around which the demonstrator is being designed is combat search-and-rescue.
 

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sferrin

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sferrin

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I'll believe it when I see it. (Their model appears to be missing tip jets.)
 
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Bgray

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They claim to have a solution for the tipjet noise and are now apparently going for the escort light-attack niche.

The problem I have, with full deference to their engineering skills, is how do you solve the problem of tipjet noise, since, well, tipjets are jets. They're going to be loud, and by virtue of being mounted on the rotor seems to eliminate a lot of possible options for lowering that noise.
 

TomS

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I'll believe it when I see it. (Their model appears to be missing tip jets.)
The Groen tipjet design is pretty unobtrusive; you really can't see the jets in photos of models at this scale. It's not like the pods on the Rotodyne, for example. Here's a picture of the tipjet design they tested for DARPA, extracted from that Vertiflite article hosted on the Skyworks website. Not easy to interpret, but I think it's basically a row of small ejector jets in slots at the trailing edge of the blade tip.

tipjet.PNG
 

yasotay

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Well they certainly have a robust team if their "Leadership Team" and "Consultants" are more than folks who sent them nice memorandum.
 
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