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  #461  
Old 06-01-2019, 12:29 PM
David Paule David Paule is offline
 
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Quote:
Originally Posted by rcarsey View Post
....Anyone not familiar with [motorgliders], they are basically airplanes with a wing loading of less than .6 lbs/sqft....
Close but not exactly. It's not wing loading based upon area, as the term customarily means, but weight divided by span squared.

For example, at Van's RV-3B gross weight of 1,100 pounds, it would need a wingspan of at least 42.12 feet to be a motorglider.

FAA's actual criteria is 3.0 kg/m^2, or (their conversion) .62 lb/ft^2. It's in AC 21.17-2A, if you're interested.

Dave
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  #462  
Old 06-01-2019, 01:48 PM
rv7charlie rv7charlie is offline
 
Join Date: May 2006
Location: Pocahontas MS
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Default speaking of...

Wish I had the reference handy to verify this, but I don't. According to something I read somewhere (doncha love that?), the FAA has that rule for certifying gliders as gliders, but it doesn't apply to experimentals. So...
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  #463  
Old 06-01-2019, 02:29 PM
David Paule David Paule is offline
 
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I think Sonex uses it to get the Xenos motorglider kits licensed as gliders.

Dave
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  #464  
Old 06-01-2019, 02:57 PM
rv7charlie rv7charlie is offline
 
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They probably did, but I'm pretty sure they didn't need to. Would the old 'primary glider', the 1st thing Paul Poberezny restored, meet the criteria? I suspect not. If you built one from plans today, would the FAA refuse to license it as an exp. homebuilt glider?
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  #465  
Old 06-01-2019, 04:22 PM
rv7charlie rv7charlie is offline
 
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What I was trying to say, is that this:
FAA's actual criteria is 3.0 kg/m^2, or (their conversion) .62 lb/ft^2. It's in AC 21.17-2A
wouldn't be applied to your homebuilt model 'xyz' glider when you apply for its exp a/w cert as a glider. Which might mean that, for instance, something that looks a lot like an RV-12 (or RV-9), (with a 'friendly' inspector) might conceivably be licensed as a motor glider.

I'll bet that a -9, with just a bit of wing tip tweaking, will out-glide every one of the 'primary gliders' that many learned to fly in back in the 20s & 30s.
https://en.wikipedia.org/wiki/Primary_glider
Paul P.'s primary glider type, at 15-1 glide ratio:
https://en.wikipedia.org/wiki/WACO_Primary_Glider
WW2 troop/cargo glider, at 12-1:
https://en.wikipedia.org/wiki/Waco_CG-4

Last edited by rv7charlie : 06-01-2019 at 04:24 PM.
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  #466  
Old 06-01-2019, 05:35 PM
David Paule David Paule is offline
 
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Actually, that criteria is applied if you're licensing it as a glider. A motorglider is licensed as a glider, I understand. A friend went through this for his Xenos motorglider. The FAA accepted it as the proper criterion.

Dave
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