Unequal Wing halfs

[coosbaylumber]

This got asked in yet another forum, without any consensis there.

But, working on yet another old-timer. This one designed in 1939. Plan says wingspan of 66 inches (for a O&R .56 engine).

One winghalf is shorter than the other by about 5/8 inch. No, this is not due to some problem with plan printing, for the two halves are side by side. This is third time now I have come upon this, and each was the standard free flight old-timer of the 1938-1939 era. They each had engine without down thrust or side thrust.

Back several years ago, I read a paragraph from old M.A.N. issue that the vogue was to just alter the wings instead of the motor position. Thus the same charisterics were expressed as pointing the engine. For without pointing the engine, several could be used and obtain the same circular flying then so popular. The small amount of drag and different lift ratio by unequal wing halves could give similar results as tilting the engine.

Ever know of unequal lengths to get same flying charisterics as an offset engine?

Wm.

[Ollie]

The torque of the engine makes the plane roll to the left. I think that the left wing has more span than the right wing on the plans. So, the wing helps control lots of engine torque under power and the plane climbing turns to the left but no spiral dive. Then the FF model turned to the right after the engine stops.

[saucerguy]

I see it's inefficient to relocate the direction of the motor, or have to trim the bird to accomodate the direction the plane wants to travel, it should fly straight forward on it's own rather then kinda side ways which produces drag. The old timers that innovated the differential wings were again onto something most discard, but is really quite relavent to the final science here.

Looking at adjusting that element has to be per individual design itself and is alot harder to fine tune rather then adding the drag, easy to do issue with the motor mount, but for the die hards, I'm sure, will pick up upon this and win competitions if they take heed to addressing in this manner and have in the past, especially since most are not now, it's really something to take into consideration with their next precision build.

[vintage1]

Well I am not so sure.

Apart froma few very oddball adaptaions, asyymetric wings have NEVER been used in full size aircraft, but offset thrust lines have in many many cases.

TYhe most peculiar I have come across is the supermarine walrus, where a lot of side thrust and upthrust was used to offest the torque and high engine mounting position.

[Batmanwpg]

Well I am not so sure.

Apart froma few very oddball adaptaions, asyymetric wings have NEVER been used in full size aircraft, but offset thrust lines have in many many cases.

TYhe most peculiar I have come across is the supermarine walrus, where a lot of side thrust and upthrust was used to offest the torque and high engine mounting position.

I believe the Italian Macchi C.202 had differential wing lengths and certainly was not an oddball!

[rebell]

...

[rebell]

It was not perhaps one of Burt Rutan designs in a previous life?:D

[kak8]

I was thinking the same thing :)

[uriah]

yes the ARES and the and the Rutan Boomerang!!! Great designs, great designer!

[yoyoML]

yes the ARES and the and the Rutan Boomerang!!! Great designs, great designer!

I absolutely love that ARES! Too bad it lost to the A-10.

What a beauty!

[AndyOne]

Asymmetric designs go back at least as far as WWII...

http://www.geocities.com/asymmetrics/

Andy.

[uriah]

who designed the A-10 anyway...? I don't personaly like it that much. The ARES I think was just a little too much money per plane.

[nauga]

who designed the A-10 anyway...? I don't personaly like it that much. The ARES I think was just a little too much money per plane.
Fairchild (Republic) produced the A-10, first flight in the early to mid 70's. The ARES was intended to be a cheap close-air support gunship, kind of like a lightweight simplified A-10. It first flew in the late 80's or early 90's. It was never really an "A-10 vs. ARES" competition, except as maybe a replacement candidate.

Nauga,
who respects firepower

[Ollie]

"But, working on yet another old-timer. This one designed in 1939. Plan says wingspan of 66 inches (for a O&R .56 engine).

"One winghalf is shorter than the other by about 5/8 inch. No, this is not due to some problem with plan printing, for the two halves are side by side. This is third time now I have come upon this, and each was the standard free flight old-timer of the 1938-1939 era. They each had engine without down thrust or side thrust."

Now give the reason for the design. Perhaps answer #2 is correct.

[pd1]

Ollie is 100 per cent correct, The free flight was to circle left under power, then power off circle right. That way you didn't have to chase them that far. I know I chased a lot of my dads planes when I was a kid. Also I was taught to build them like that back in the 50's, for just those reasons.

[Sean Foster]

The engine is tilted slightly to one side and pointed down to minimize it's own effects on the airplane. Since props turn in the clockwise direction (for the most part), there is a swirling motion around the fuselage. When it reaches the vertical stabilizer, it causes the tail to move right (which turns the plane left). When you take off, this is when you will notice it most.

There are other factors that affect flight too, and I heard the torque of the engine which causes the plane to roll left. This is true, but there is another factor encountered in slower flight called p-factor. When the plane has a high angle of attack, the prop blades decending on the right side take more of a "chunk" out of the air than the ascending prop blades on the left side. This causes the plane to yaw left.

So, as you can see, with torque rolling the plane left, swirling propwash yawing the plane left, and p-factor also yawing the plane left, designers must find a way to overcome this. For instance, pointing the engine slightly right takes a little "force" off the left side of the vertical stabilizer and adds a little to the right, balancing things out. Also, many aircraft will have their vertical stabilizer pointed slightly left of center. This, along with pointing the engine slightly right, helps out greatly. If you look at a Cessna single engine aircraft (such as the 150), you might be surprised at how much the engine is pointed right.

I am not 100% certain that the reason for a slightly longer left wing was the designer's way of counteracting this left-turning tendency as it is an unusual approach; however, when we yaw a glider to the right with just the rudder, the right wing drops and the left wing rises due to the ever-so-slight difference in lift caused by the ever-so-slight difference in speed between the two wings, so it stands to reason that this left-wing-up design was probably to counteract the left-wing-down effect of torque/propwash/p-factor.

Anyways, I know this is long-winded and a few months after the last post, but I hope it helps those interested.