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UFO- Useless Flying Object

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litespeed

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Here in Australia, we have some real characters when it comes to getting in the air.

David Rowe is definitely one such man.

This is the fourth of his series of UFO's that he has built and it even has retracts.

Note how he gets in.
 
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BJC

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Neat!

Any photos of the structure available? Empty weight?

Add some LEDs and a controller for them, fly just at dusk ... could have lots of fun.


BJC
 

cluttonfred

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Wow, great stuff, thanks! He's got something interesting going on with the controls, perhaps because of the belly access door? I'd love to learn more about this plane -- structure as BJC said, but also airfoil, flying characteristics, etc. I am also curious why he chose to use a flat lower surface, easier to build but essentially designing in anhedral instead of dihedral. Regardless, his design does seem to put to rest any speculation that a low aspect ratio design would be incredibly hard to fly or have insufficient control authority.

Low aspect ratio designs are a particular interest of mind and something I think deserves more attention in reducing the cost, building time, workshop space required, etc. for a little sport aircraft. A 12' diameter circular wing gives 113 sq ft of wing area, build the fuselage/center section as one 12' x 4' piece with folding or detachable 4' span outer panels and the whole thing could be built and hangared in a 20' shipping container with room to spare.
 

litespeed

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What I do know is that it weighs in under a MTOW of 300kgs or 661lbs. To meet our 95.10 regulations.

Apparently the first two versions had issues about the weight and balance but were flyable.

Version 3 and 4 are stable and not difficult to fly.

Construction is mainly wood.

It has no nasty habits.

The builder is a bloody legend, thats Aussie for top bloke or the Ducks guts or.........
 

Autodidact

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Low aspect ratio designs are a particular interest of mind and something I think deserves more attention in reducing the cost, building time, workshop space required, etc. for a little sport aircraft. A 12' diameter circular wing gives 113 sq ft of wing area, build the fuselage/center section as one 12' x 4' piece with folding or detachable 4' span outer panels and the whole thing could be built and hangared in a 20' shipping container with room to spare.
Orion once said that the Dcl/Dalpha curve drop off diverged for very low aspect ratios, from that simple equation you see in the books. From what I've read about tip effects, apparently the whole wing is a wing-tip sort-of with very low aspect ratios, and the down wash aft of the wing from the large tip vortices pulls the air in front of the wing downwards, giving a smaller induced angle of attack over a much larger percent of the span. Need to get those NACA reports out...
 

cluttonfred

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Here you go, Autodidact, the two classic Zimmerman papers:

NACA-TR-431 Characteristics of Clark Y airfoils of small aspect ratios (1933)

NACA-TN-539 Aerodynamic characteristics of several airfoils of low aspect ratio (1935)

And continuing my quick and dirty math from above, a 16' diameter circular wing would have a whopping 201 sq ft of area. With some care that might be able to fold up the wings carrier-style (two 6' outer panels on a 4' fuselage/center section) and still fit in a 20' shipping container.
 
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Autodidact

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Thanks. There seems to be something wrong with the NASA technical reports server or the pdf files; each time I downloaded one, it locked my machine up for a while, and they are only about 1 megabyte.
 

Hot Wings

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Thanks. There seems to be something wrong with the NASA technical reports server or the pdf files; each time I downloaded one, it locked my machine up for a while, and they are only about 1 megabyte.
Works for me. But I'm forced to use the Win 8.1 box at the moment.

The XP box decided to BSD and I haven't fixed it yet... The combination of XP and my antivirus would sometimes decide that some PDFs were .... bad.

Really like the UFO! Almost makes me want to start yet another project :whistle:
 

Winginit

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I admire the builders ingenuity and building skills, but other than being a conversation piece, I'm not sure what it accomplishes. Does it actually do anything "better" than conventional tractor or even pusher designs ? I would also have a lot of concerns about having to enter/exit the airplane from underneath. In the event of a landing gear collapse or other landing mishap, is the canopy quickly removable ? I don't mean to sound critical of the builders design, because he obviously put great effort into both designing and building the airplane and deserves credit and respect for doing so. There is always something to be said for doing something just to prove you "can". :)
 
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StarJar

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It sure was a short take off. He probably gets a lot of vortex lift at the substantial tips.
I think the v-bars at the top of the stick are his elevon mixers.
I'm sure he would feel a bit claustrophobic if he didn't have a releasable canopy.
 

cluttonfred

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I am inspired! It seems to me that this may be a case in which a trigear pusher makes real sense. A pusher engine on a pylon above the trailing edge would get the prop clear of the ground, visibility would be improved and the main gear could be somewhat shorter, perhaps with a shock-absorbing nose gear formate the nose does come down on landing. Maybe a near-ultralight version with a largish paramotor engine?
 
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