Full Scale Stunter

Hey, Mister...want to have a little fun?? How good are your powers of observation? Here's a photo of a full scale Extra 300...it was in a reference in the Extra 300 construction article which ran in Model Aviation for several months. It was RC, but there was still a lot to learn from the article.

Here's my challange to you.....how many aerodynamic features can you identify from this photo? They may or may not have any correlation to our size stunters, but it's still fun to study and think about and to see what the "full sized" guys do.

My observations are at the bottom of this post...don't peek until you have come up with your own. See how many design features you can spot.

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1) Thrust line, wing center line, and horizontal stablizer are close to an "in-line" layout. Thrust line and stab are both only a few inches above the wing centerline.

2) Airfoil....this really surprised me. The leading edge is very blunt, and the bottom of the "airfoil" appears to be completely FLAT, and I assume it is symetrical, though it doesn't necessarily have to be. Maybe the designer of the Extra used to fly *combat*.

3) A very high taper in wing thickness, root to tip. Roughly 50%(?)or even possible more!

4) Also a large taper in the wing, planform view. Again, it looks like it could be as much as 50%. ??

5) Landing gear location approximately on the wing leading edge at the root, though I have no idea where the CG is, and that is the important issue.

6) Three bladed prop.

7) There appears to be a weight balancer hanging down from the flaps.

8) Note the size of the pilot relative to the rest of the plane. Many of our models' pilots are off scale by a lot.

9) Nice paint scheme!!

OK, how many items did you pick up? Again, it may have little or no bearing on our models, but it was fun anyway.

Cheers,

You left out: tail dragger!

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"If you must choose between two evils, pick the one you've never tried before."

I'd be checking the power to weight ratio here also. At a best guess I'd think the real machine will be down a tad from what our models are at. But still, the main idea is that the real machines are pushing for the same type of ratio's as we are. Lets see, hmmm, ..300hp divided by airframe weight, equals............

Not many R/C models have a landing light which actually lights up. Also the pilot is looking at the camera: most models have the "pilot" looking straight ahead.

Hi Warren,

That "weight balancer" on flaps is called a SPADE and it is actually on the aileron to aerodynamically "load" the aileron during displacement so as to make the control forces required of the pilot less. When you get up close to an aerobatic airplane, be sure to take a look at this device as it is a very simple buy very efficient piece of engineering. I haven't flown an Extra but I have flown a Pitts Special with and without the spade and you wouldn't believe the difference.

FLY SAFE, John:)

I've posted this before. If you want to see a full scale stunter, go to www.qrz.com. Then in the block enter my ham callsign K6BSU. That will take you to my page and a full-size stunter.

Cool, Floyd. That's a rare bird, for sure. About 1932-35?
Kelvin

>I've posted this before. If you want to see a full scale
>stunter, go to www.qrz.com. Then in the block enter my ham
>callsign K6BSU. That will take you to my page and a
>full-size stunter.
>
>Floyd Carter

>2) Airfoil....this really surprised me. The leading edge
>is very blunt, and the bottom of the "airfoil" appears to be
>completely FLAT, and I assume it is symetrical, though it
>doesn't necessarily have to be. Maybe the designer of the
>Extra used to fly *combat*.

I have time in the Extra 300 and it is an exceptionally well made airplane. Some of my observations while spending time in, around, & flying the Extra are that the airfoil is developed by simply rounding the leading edge and making the balance of the airfoil flat. The line from the trailing edge is tangent to the L.E. rounding. The wing is all composite construction and the cockpit has a placard limiting the "G" load to + & - 10.5 "G"s. Ultimate load is, of course, 50% greater.

>4) Also a large taper in the wing, planform view. Again,
>it looks like it could be as much as 50%. ??

The leading edge is swept back a fair amount and the trailing edge is swept forward even more. The airplane does incredible snap rolls and you can stop the rotation pretty close to instantly. I have a little more than a thousand hours in Pitts Specials of all varieties and love those biplanes, however, the Extra outperforms them.

>6) Three bladed prop.
The prop is a composite blade and is made by either MT or Hoffman, depending upon the serial number of the Extra.

>7) There appears to be a weight balancer hanging down from
>the flaps.
As was stated elsewhere in this thread this is a "spade" which assists movement of the aileron when deflected, reducing effort on the part of the pilot. The ailerons are symmetrical, nearly full-span, and are hinged in the vertical center (same as our stunt ships) and without spades require high stick forces to move at aerobatic speeds. The Extra I flew had two spades per aileron due to the aileron being so long.

>8) Note the size of the pilot relative to the rest of the
>plane. Many of our models' pilots are off scale by a lot.
Good point!

>9) Nice paint scheme!!
Interestingly enough, the paint scheme is mandated in the FAA Type Certificate Data Sheet and may not be changed without consulting with the factory. This is due to the composite construction and heat/UV absorbtion sitting in the sun.

>OK, how many items did you pick up? Again, it may have
>little or no bearing on our models, but it was fun anyway.
>
>Cheers,
>
>Warren Wagner

Don't forget those fake rivets and the alien monster fake pilot. Steve

AND it has a four stroke engine!!!

Not mentioned is that the trailing edge is about 3/4 of an inch thick
and squared off like the edge of a desk. As I understand it this is an important feature of the airfoil for low speed/high AOA effeciency.
Andrew Raney
Dallas Tx

The Lancair aircraft also have a squared off Trailing Edge on the ailerons.

At EAA AirVenture in Oshkosh last week:

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http://www.flightadventures.com/pattywagstaff/

Got your attention?

Hi Ed,

When I was flying airshows as right wing (#3) with the "Team America" formation aerobatic airshow team on the airshow circuit I got to see Patty Wagstaff's show up close and personal many times and she flies even better than she looks. She was, after all, 3 time National Champ and flew at the Worlds. It is worth the price of admission just to see her show. I think that it is the best show since the late Leo Loudenslager's.

>and she flies even better than she looks.

I was at AirVenture Saturday and saw her fly.
I was right up on the flightline, about
30 feet away from her aircraft while
she was waiting to taxi out to the runway.
The performance was so amazing it is almost
beyond words for me.