Aileron authority

[PT20J]

According to the Service Manual, the M20J has a wing loading of 16.59 lb/ft² at 2900 lb. The wing area is 174.786 ft² if you want to calculate it for other weights. The ailerons are 11.4 ft².

The pressure on the ailerons is lower on the top than the bottom, so they tend to drift up in flight (That's why they get rigged 1 deg down). This puts the tubes in compression and can flex them, but probably not enough to feel. But it will increase the friction through the guide blocks which should be kept well lubed. Roger Hoh was a contract test pilot who flew the Predator during development. The roll rate was too slow to meet spec and so Mooney shortened the flaps and lengthened the ailerons to increase their area. Roger told me that this caused the tubes to flex so much at high speed that they would bind and the stick would stay wherever you put it. Maxwell's changed out the wing for one from a K, so it no longer has this problem.

According to Ron Blum, the Mooney's with squared wing tips have higher roll control force than the ones with the sculpted wing tips because the new tips get the aileron outboard end away from the tip vortex.

Skip

[N201MKTurbo]

5 hours ago, PT20J said:

According to the Service Manual, the M20J has a wing loading of 16.59 lb/ft² at 2900 lb. The wing area is 174.786 ft² if you want to calculate it for other weights. The ailerons are 11.4 ft².

The pressure on the ailerons is lower on the top than the bottom, so they tend to drift up in flight (That's why they get rigged 1 deg down). This puts the tubes in compression and can flex them, but probably not enough to feel. But it will increase the friction through the guide blocks which should be kept well lubed. Roger Hoh was a contract test pilot who flew the Predator during development. The roll rate was too slow to meet spec and so Mooney shortened the flaps and lengthened the ailerons to increase their area. Roger told me that this caused the tubes to flex so much at high speed that they would bind and the stick would stay wherever you put it. Maxwell's changed out the wing for one from a K, so it no longer has this problem.

According to Ron Blum, the Mooney's with squared wing tips have higher roll control force than the ones with the sculpted wing tips because the new tips get the aileron outboard end away from the tip vortex.

Skip

So the link is on the bottom of the aileron. The lift forces are upward, so it is pulling on the rod. The bell crank in the wing has the rod ends right next to each other. How is that turning into compression of the aileron tubes? I had them open the other day, I will need to look at them again and see.

[Utah20Gflyer]

The Mooney has a longer than average wing which generally results in slower roll rate as others have stated.  This might create the impression of running out of aileron if you were used to aircraft with shorter wings and a faster roll rate.  
 

 

[PT20J]

I never compared wingspans, so I looked up a few:

A36 (square wing tips) 33'6"

PA28 (taper wing) 35'6"

C-182 36-0"

M20J (sculpted wingtips) 36'1"

SR-22 38'4"

The Cirrus is going to be a tight fit for a lot of T-hangars which seem to range from about 39' to 42' wide. I think that most manufacturers shoot for the longest wing they can get for lower induced drag while still fitting into a hangar. Not sure why the Bonanza is shorter than most.

[Fly Boomer]

2 hours ago, PT20J said:

I think that most manufacturers shoot for the longest wing they can get for lower induced drag while still fitting into a hangar. Not sure why the Bonanza is shorter than most.

I think the Bonanza is remarkably fast (compared to the Mooney) given its flat plate equivalent, and other characteristics such as this one.

[1980Mooney]

1 hour ago, PT20J said:

I never compared wingspans, so I looked up a few:

A36 (square wing tips) 33'6"

PA28 (taper wing) 35'6"

C-182 36-0"

M20J (sculpted wingtips) 36'1"

SR-22 38'4"

The Cirrus is going to be a tight fit for a lot of T-hangars which seem to range from about 39' to 42' wide. I think that most manufacturers shoot for the longest wing they can get for lower induced drag while still fitting into a hangar. Not sure why the Bonanza is shorter than most.

 

18 hours ago, PT20J said:

According to the Service Manual, the M20J has a wing loading of 16.59 lb/ft² at 2900 lb. The wing area is 174.786 ft² if you want to calculate it for other weights. The ailerons are 11.4 ft².

The pressure on the ailerons is lower on the top than the bottom, so they tend to drift up in flight (That's why they get rigged 1 deg down). This puts the tubes in compression and can flex them, but probably not enough to feel. But it will increase the friction through the guide blocks which should be kept well lubed. Roger Hoh was a contract test pilot who flew the Predator during development. The roll rate was too slow to meet spec and so Mooney shortened the flaps and lengthened the ailerons to increase their area. Roger told me that this caused the tubes to flex so much at high speed that they would bind and the stick would stay wherever you put it. Maxwell's changed out the wing for one from a K, so it no longer has this problem.

According to Ron Blum, the Mooney's with squared wing tips have higher roll control force than the ones with the sculpted wing tips because the new tips get the aileron outboard end away from the tip vortex.

That is a very interesting explanation of the development history. 

The Slingsby T-3A Firefly which beat out the Mooney M20T as the Air Force Trainer in 1991 had a wingspan of 34 ft 9 in. 

It had a wing area of 136 sq ft vs. 175 sq ft for the Mooney as noted above.  Also, it was lighter than the Mooney - 

• Slingsby T3-A Empty 1,750 lbs. - Max 2,550 lbs
• Mooney N20T Empty 1,916 lbs. - Max 2,900 lbs (per Aviation Consumer) Mooney Predator - Aviation Consumer

Both planes had the 260 hp Lycoming so the Mooney suffered - both from too much weight and too much wing without enough aileron authority.

The Aviation Consumer article test (dated 2001 before Maxwell changed the wing) notes:

• "the Predators control forces are quite high, especially in roll. For pattern work, slow flight, stalls and routine maneuvering, the stick makes these forces less noticeable than they are with a yoke.

  However, in aerobatics, roll forces escalate, producing a certain stick-in-concrete sensation. In fact, the Predator wont do a conventional level slow roll, but needs to have its nose coaxed well above the horizon before initiating a roll, with both hands and a good grunt. We aren't talking about a Pitts Special, here."

I wonder if Mooney went to thicker wall tubulars on the aileron control rods to reduce flex but probably still produced binding.  But it also helps explain why Mooney lost out on the contract.

Also it is interesting to know that Maxwell's Predator is really a "RestoMod" - with a "K" wing.

 

[PT20J]

2 minutes ago, 1980Mooney said:

Also it is interesting to know that Maxwell's Predator is really a "RestoMod" - with a "K" wing.

It also now sports a modern glass cockpit.

[1980Mooney]

3 minutes ago, PT20J said:

It also now sports a modern glass cockpit.

Also in true RestoMod fashion, I see that Maxwell also replaced the original 260 hp Lycoming engine with a 300 hp Lycoming AEIO-540 - so that it can keep up with other Mooney's....

Mooney’s Almost-Warbird Returns to the Texas Skies - Plane & Pilot Magazine (planeandpilotmag.com)

[A64Pilot]

5 hours ago, PT20J said:

I never compared wingspans, so I looked up a few:

A36 (square wing tips) 33'6"

PA28 (taper wing) 35'6"

C-182 36-0"

M20J (sculpted wingtips) 36'1"

SR-22 38'4"

The Cirrus is going to be a tight fit for a lot of T-hangars which seem to range from about 39' to 42' wide. I think that most manufacturers shoot for the longest wing they can get for lower induced drag while still fitting into a hangar. Not sure why the Bonanza is shorter than most.

To me it’s interesting to note that I believe all the Modern Cessna single engine high wing aircraft have I believe essentially the same wing area of a M20, so the C-210 at I think a 4,000 lb gross weight has no more wing than a C Model Mooney and a C-172 has the same too, The Bo does have a little more but not a whole lot, about 6 sq ft maybe?

A C-140 and C-152 carry I believe 160 sq ft so only roughly 15 sq ft less than the Mooney and C-210, but the max gross on a 140 is only 1450 lbs.

The Mooney and C-210 and C-177 are laminar flow.

The Bonanza does not have a laminar flow wing, so add that to the surprise that they are as fast as they are. I think the Bo has a shorter non laminar flow wing just because it’s a very old as in 1940’s design. If the design had been updated I think it would be completely different. I’m astonished they never “fixed” the flat bottom, I think that’s the source of their yaw instability, not the V tail.

[47U]

8 hours ago, 1980Mooney said:

Both planes had the 260 hp Lycoming so the Mooney suffered - both from too much weight and too much wing without enough aileron authority.

Unfortunately, the Slingsby T-3 Firefly also suffered, but in a different aspect, resulting in several fatalities.  What was the name of the Light Plane Maintenance article?  Vapor Lock by Design.  

I remember reading speculation that Slingsby was awarded the T-3 Firefly contract because of the U.K.’s political support during that period.  I’m not saying that was wrong, but failing to properly integrate the big Lycoming into the T-3 was wrong.

Sorry about the thread drift…

[A64Pilot]

Civilians “politicians” are who buys Military hardware, for some reason the general public thinks its Generals but it not. So Military hardware is often bought based on political necessities not need or performance. Knowing this the Military Industrial complex does it’s best to play to those political realities.

It’s a system with huge amounts of money ripe for abuse. Very often fly-offs or other performance trials are pure theater what will be bought is already decided prior to the trial. Not always but usually the fix is in.

This aircraft for example was one heck of a CAS/COIN airframe, especially the COIN part, but it wasn’t politically connected and the AF wasn’t going to consider anything with a propellor, but it’s orders of magnitude better than arming a Crop Duster.

https://en.wikipedia.org/wiki/Piper_PA-48_Enforcer

[1980Mooney]

8 hours ago, 47U said:

Unfortunately, the Slingsby T-3 Firefly also suffered, but in a different aspect, resulting in several fatalities.  What was the name of the Light Plane Maintenance article?  Vapor Lock by Design.  

I remember reading speculation that Slingsby was awarded the T-3 Firefly contract because of the U.K.’s political support during that period.  I’m not saying that was wrong, but failing to properly integrate the big Lycoming into the T-3 was wrong.

Speculation is right.  The competition included the SIAI-Marchetti SF.260 (even lighter than the T3-A at 1,660 lbs. Empty weight), the Mooney M20T Predator and the Slingsby T3-A.  I don't recall why the SF.260 wasn't picked but it was clear that the Mooney was unqualified due to its handling deficiencies/issues as well as heavy.  Perhaps the Air Force should have cancelled the competition and stuck with the C-172 (T-41 Mescalero) although they flew the T3-A much more aggressively.   

Like most things in General Aviation, Cirrus came to dominate.  The Air Force picked the SR-20 (T-53A Kadet II) as their basic trainer.  All Air Force pilots in the last nearly 25 years learn to fly in a Cirrus.

"The T-53s (Cirrus SR-20) represent the backbone of the Academy's Powered Flight training program in which over 500 cadets participate annually."

[Pinecone]

Many USAF pilots do not attend the USAF Academy.  Those that do not attend IFT and fly the Diamond DA-20, NOT Cirrus.

[1980Mooney]

43 minutes ago, Pinecone said:

Many USAF pilots do not attend the USAF Academy.  Those that do not attend IFT and fly the Diamond DA-20, NOT Cirrus.

Ooh.. the other “plastic plane”!  Thanks for confirming that “aluminum is dead” as far as Air Force initial training goes.