Leadville (KLXV) in an NA Mooney?

[donkaye]

5 minutes ago, MikeOH said:

You might practice what you preach and read the post above yours, from Cliffy.

I did and commented on it.  And btw, I don't care if anyone chooses to follow any of my recommendations or postings.  If you think you can benefit from them great.  Otherwise...

[MikeOH]

1 minute ago, donkaye said:

I did and commented on it.

I agree with Cliffy's comment, "Yes it can be done even at less than 10 feet but to what avail is it REALLY NECESSARY for the average pilot?". It's been my point all along.

So, do you agree with him or not?

[donkaye]

10 minutes ago, MikeOH said:

I agree with Cliffy's comment, "Yes it can be done even at less than 10 feet but to what avail is it REALLY NECESSARY for the average pilot?". It's been my point all along.

So, do you agree with him or not?

Mike, you're right.  I modified my post above to say that I agree with most of what he says.  But there will come a time where it would be beneficial for an average pilot to really understand both the benefits and potential problems associated with ground effect, the benefits being on takeoff and the problems being associated with energy dissipation on Mooney landings.

[MikeOH]

4 minutes ago, donkaye said:

Mike, you're right.  I modified my post above to say that I agree with most of what he says.  But there will come a time where it would be beneficial for an average pilot to really understand both the benefits and potential problems associated with ground effect, the benefits being on takeoff and the problems being associated with energy dissipation on Mooney landings.

With that I agree 100%: knowledge of ground effect and how it affects performance on both take off and landing is absolutely important for all pilots.

Have a good evening, Don

[Pinecone]

16 hours ago, donkaye said:

My experience with ALL students has been that, even though they may want to, they just won't stay in ground effect.  In ground effect induced drag is reduced by an amazing 48%.  Everyone thinks they are going to hit the ground.  Why?  The Mooney wing is a little over 36 feet in length.  Ground effect is 10% of the wing length or about 3 feet.  But the landing gear extends about 3 feet.  So just as the wheels leave the ground you need to level the plane a few inches off the ground.  People just won't do that.  However, if you do, the plane will accelerate much more quickly to Vx, where you can then start your climb.

Lowest height above ground gives you the most reduction in induced drag.  The good news is that with how close our wing is to the ground, we can get a lot more benefit that a high wing.   As we all know from being slightly fast and trying to land.

 

"this means a rapid drop off of ground effect as height above ground increases so that it is typically reduced to half of the adjacent-to-surface maximum at a height above ground which is equal to 10% of the wing span or rotor diameter, to a quarter of this at a height equivalent to 25% of the wing span or rotor diameter and to 10% of it by the time this height is equivalent to 90% of the wingspan or rotor diameter"

[skykrawler]

Hmmm.....My thoughts are we should all have been trained for soft field takeoff which is similar to what Mr Kaye is describing.

Doing it with the gear retracted might not be the most clever thing.   Drag of gear at low airspeed is not so great.

Normally the acceleration to Vx is pretty quick and doesn't require a gear retraction to help the acceleration.  Vx and Vy at Leadville on a warm day are pretty much the same number.

The FAA "Flying Handbook" - which I think is a pretty good document - says 'if the runway is long enough and no obstacles exist, ground affect can be used to the pilots advantage by using the reduced drag to improve initial acceleration.'  Which is pretty much a statement of fact.

https://www.faa.gov/sites/faa.gov/files/regulations_policies/handbooks_manuals/aviation/tips_on_mountain_flying.pdf

https://www.faasafety.gov/files/events/NM/NM07/2023/NM07120280/FAA-P-8740-02-DensityAltitude.pdf

 

[Shadrach]

59 minutes ago, skykrawler said:

Normally the acceleration to Vx is pretty quick and doesn't require a gear retraction to help the acceleration.  Vx and Vy at Leadville on a warm day are pretty much the same number.

This was the point I was trying to make earlier with regard to my experience climbing >1000fpm with the gear down. Below about 80KIAS the drag from the gear is a small percentage of total drag.  
At SL, Vx for an M20J at MGW is 69KIAS. At 10,000ft,  it’s 71KIAS. 

[midlifeflyer]

5 hours ago, skykrawler said:

Hmmm.....My thoughts are we should all have been trained for soft field takeoff which is similar to what Mr Kaye is describing.

It is. Modified soft field takeoff is standard for mountain instruction  and especially environments like Leadville where you are ultimately a test pilot if your POH doesn't include it in the performance section. 

And yes, we were all trained in soft field operations, but many have been trained for it at hard runways. Even most grass runways don't require soft field technique. When I was doing primary training (and when I cover them in flight reviews or transition training), I tried to make the "soft field" part of the curriculum a bit more realistic, discussing other situations where soft field technique would be helpful. Wet and slushy runways; concerns about landing with damaged landing gear; and, of course, very high density altitude takeoffs.

But, unless you are covering it in flight reviews, your private checkride might be the last time you did or simulated one. Personally, I think that alone militates against the 1-foot pass, as well as the teeny likelihood you will ever need to use it.

 

 

 

[Paul Thomas]

3 ft off the ground accelerating... is that with the gear up or down? If it's gear up, there is absolutely no way that I would EVER do that. We'll wait for a better day to fly out; the risk of a gear up is not worth it to me.

With the gear down, I would do it as a training exercise, but would not do a takeoff where performance requires it.

I've had airplanes that linger in ground effect to accelerate and I didn't like it -- and that was without mountains around. I just don't have the much risk tolerance these days.

[dkkim73]

12 hours ago, donkaye said:

Personally, I do accelerate to 5 knots below Vx on most takeoffs before I climb out.  It happens rapidly in the M20M.  I hit Vx on the climb.

For the Acclaim, I noticed on the Checkmate card Vr is listed as 55 and "liftoff" at 77 KIAS, Vx (nominal) is 85. This seems to square with my early sense of normal take-offs so far and your (much longer) long-body experience. Vx comes fairly quickly. Different case than the OP, of course, NA vs. TN, and 4 cyl + lighter plane. 

-----

A few thoughts on the overall discussion: 

That 3 feet being discussed is still with the gear down, so as long as you're not screaming fast, it's doesn't seem insane. I always end up flying this low twice on every flight, even when I am not specifically planning to. 

I find it weirdly non-intuitive to judge height in this plane. I feel low when I start flying and take off, and somehow the same height on landing seems much higher. I think it's some kind of perceptual "change blindness". The standard tricks (look down to the end of the runway, Lindbergh reference, etc, all help) but it's still uncanny. I believe it will get better with familiarity.  The Microkit LHS (landing height system) is truly great in this respect, and also helps immensely with the low approach and "bleed-it-off" exercises. I wonder about being able to turn it on for takeoff in the context of this discussion? Note that that is usually set up to report height above the resting position. So "2, 2, 2..." means the tires are 2 feet above the ground. Which would be 5 feet for the wing in this discussion. 

We all practice things "closer" to the edge (under controlled circumstances) to expand our zone of comfort for normal ops. E.g. power-on stalls make my a bit nervouse in the Mooney given what I've read of the spin characteristics, so I'm super-aware with the rudder... But they need to be done. Anyhow, I think that's part of the point, and different for many of us. I want to be better at low approaches in the Mooney. I had to fly faster and low yesterday on final, got vectored all over trying to keep my speed up, and switched to a short runway, further away, at the end (it was great practice for what it would be like to transition from a fast ILS, I think). I did not like feeling fast on short final. But the practice helped...

 

PP thoughts only, not a CFI

[donkaye]

43 minutes ago, dkkim73 said:

 

We all practice things "closer" to the edge (under controlled circumstances) to expand our zone of comfort for normal ops. E.g. power-on stalls make my a bit nervouse in the Mooney given what I've read of the spin characteristics, so I'm super-aware with the rudder... But they need to be done.

In a well rigged Mooney I have never had an airplane snap into a spin at the stall with the ball centered.  To prevent a ridiculously nose up attitude on a power on stall it should be started at approach speed and at 65% power.

I have had airplanes that were not properly rigged start to roll off on a wing near the stall, but recovery was immediate and there was no uncontrolled spin entry.  The only time I went into an inadvertent spin in a Mooney was about 25 years ago practicing cross controlled stalls out of a left turn.  Luckily the stall practice was started at 6,000 feet and recovery took 1,000 feet.  My article about that can be found on my website www.donkaye.com under useful aviation articles.

As a point of interest and comfort, every Mooney that came out of the factory was flight tested, and the stall strips were adjusted for each airplane to stall straight ahead in a power off stall.

[PT20J]

The Mooney sits on the ground at a positive angle of attack. Lift is a function of both AoA and true airspeed squared. As the speed builds, lift increases and when the airplane leaves the ground, it is set up for a climb. To stay in ground effect requires lowering the nose as the airspeed increases which takes a push on the elevator. This is contrary to our normal procedures and will not go well unless it is practiced.

[PT20J]

All the Mooneys were test flown and the stall strips adjusted to meet certification requirements of not more that 15 deg roll when corrective control input is delayed for 1 second. The Mooney wing is pretty sensitive to small variations in shape. It is not uncommon to find the stall strips placed noticeably differently on the two wings due to manufacturing variations. My airplane had a right leading edge wing ding that was apparently bondo'd between the landing light and the wingtip. If you look hard you can see a slight irregularity in the leading edge, but you have to look for it. It always drops the right wing a little in the stalls. 

[dkkim73]

@donkaye and @PT20J, thank you for that. To be clearer, my plane is fairly neutral in the stall AFAICT, and generally docile in slow flight (reminds me to go practice some...). I was thinking of some of the things I've read, including by Don, and videos I've seen about Mooney spins. All info that gave me a healthier respect for the stall in this plane. 

Took a bit to get used to the G1000's slip/skid indicator. A few including my transition instructor just pointed out the nose motion is a pretty good indicator. Now I'm really drifting the thread. 

[cliffy]

As far as Mooney spins are concerned-

I had a nice conversation with Bill Wheat many years ago in which he described an 

entry into a spin in testing that he carried too far-- 5 turns

He said he almost didn't get out of it and would never do multiple spins in Mooneys again

Occasionally we hear on this site some who purposefully play with spins in Mooneys

I think Bill Wheat's admonition is a word to the wise if the subject comes up. 

I think the placard says -- "Spins NOT approved" in Mooneys.?

[PT20J]

Spins actually take a couple of turns to develop to the point where the aerodynamic forces are balanced. Before spins become developed, they are called incipient spins. Incipient spins are usually easily recoverable by prompt application of controls. After a spin becomes developed, depending on the design of the airplane, it can take multiple turns to recover if recovery is possible. 

[donkaye]

1 hour ago, cliffy said:

As far as Mooney spins are concerned-

I had a nice conversation with Bill Wheat many years ago in which he described an 

entry into a spin in testing that he carried too far-- 5 turns

He said he almost didn't get out of it and would never do multiple spins in Mooneys again

Occasionally we hear on this site some who purposefully play with spins in Mooneys

I think Bill Wheat's admonition is a word to the wise if the subject comes up. 

I think the placard says -- "Spins NOT approved" in Mooneys.?

To be perfectly clear I don't and wouldn't recommend anyone doing cross controlled stalls in a Mooney.  At the time I was doing them with students the FAA was concerned about recovery from the base to final turn cross controlled stall.  For that matter it is still a concern, but after my experience with them many years ago I won't be doing them in a Mooney and neither should you.

[Hank]

2 hours ago, PT20J said:

Spins actually take a couple of turns to develop to the point where the aerodynamic forces are balanced. Before spins become developed, they are called incipient spins. Incipient spins are usually easily recoverable by prompt application of controls. After a spin becomes developed, depending on the design of the airplane, it can take multiple turns to recover if recovery is possible. 

 

50 minutes ago, donkaye said:

To be perfectly clear I don't and wouldn't recommend anyone doing cross controlled stalls in a Mooney.  At the time I was doing them with students the FAA was concerned about recovery from the base to final turn cross controlled stall.  For that matter it is still a concern, but after my experience with them many years ago I won't be doing them in a Mooney and neither should you.

This is what my Owners Manual says about spins:

So I stay away from them. I was very nervous doing power-on stalls during my Instrument checkride . . . .

[PT20J]

There is no reason to fear stalls, if done at reasonable altitude and the ball is in the center. The biggest mistakes I see are

1. Not keeping the ball centered.

2. Slowing faster than 1 knot/second.

3. Having an unnecessarily nose high pitch attitude at the break. This usually happens in power on stalls if power is added before getting slowed to about 1.1 Vs.

4. Trying to correct a wing drop with aileron.

5. Pitching down excessively during the recovery especially for power on stalls. 

I do stalls during a flight review until the pilot feels comfortable. 

[Hank]

3 minutes ago, PT20J said:

There is no reason to fear stalls, if done at reasonable altitude and the ball is in the center. The biggest mistakes I see are

1. Not keeping the ball centered.

2. Slowing faster than 1 knot/second.

3. Having an unnecessarily nose high pitch attitude at the break. This usually happens in power on stalls if power is added before getting slowed to about 1.1 Vs.

4. Trying to correct a wing drop with aileron.

5. Pitching down excessively during the recovery especially for power on stalls. 

I do stalls during a flight review until the pilot feels comfortable. 

Stalls aren't a problem. But a Power-On stall in a Mooney, even at just 65% power as recommended in my Owners Manual, is a bird of completely different feathers. I obviously performed them alright, even the turning one, but I was very nervous, very careful and recovered rapidly at the burble, not waiting for the break. After all, the Feds want us to learn the warning signs and demonstrate "stall avoidance," so that's what I did (in 2010).

[kortopates]

39 minutes ago, PT20J said:

There is no reason to fear stalls, if done at reasonable altitude and the ball is in the center. The biggest mistakes I see are

1. Not keeping the ball centered.

2. Slowing faster than 1 knot/second.

3. Having an unnecessarily nose high pitch attitude at the break. This usually happens in power on stalls if power is added before getting slowed to about 1.1 Vs.

4. Trying to correct a wing drop with aileron.

5. Pitching down excessively during the recovery especially for power on stalls. 

I do stalls during a flight review until the pilot feels comfortable. 

Excellent points and especially #4 but nothing wrong with pitching down till the you feel light in the seat. This is after all what the upset recovery schools teach these days and the ACS no longer makes any statements about minimizing altitude loss. Instead the emphasis is on "immediately recovering from the stall by reducing the angle of attack". 

No matter how bad a wing might be dropping off in the stall, an immediate push down that makes you light in the seat will very promptly recover back to flying speed with wings leveled and the pilot can transition back to climb attitude to return to the starting altitude. 

So personally I think its a big confidence booster for those fearful of power on stalls - which is required to the full break these day for private students and whichever the DPE calls for on the Commercial. 

The other reason for pushing till light in the seat is that folks where focusing on preserving altitude to only get into a secondary stall; usually more violent than the first.

[Fly Boomer]

6 hours ago, PT20J said:

All the Mooneys were test flown and the stall strips adjusted to meet certification requirements of not more that 15 deg roll when corrective control input is delayed for 1 second. The Mooney wing is pretty sensitive to small variations in shape. It is not uncommon to find the stall strips placed noticeably differently on the two wings due to manufacturing variations.

What about the TKS installs after the airplane has left the factory?  Do you know if the people doing the post-factory TKS installs run through the same test pilot routine with the strips taped on until the airplane behaves as it did when it left the factory?

[PT20J]

1 hour ago, Fly Boomer said:

What about the TKS installs after the airplane has left the factory?  Do you know if the people doing the post-factory TKS installs run through the same test pilot routine with the strips taped on until the airplane behaves as it did when it left the factory?

Well, they have to figure out where to place those stall strips somehow. 

[cliffy]

4 hours ago, donkaye said:

At the time I was doing them with students the FAA was concerned about recovery from the base to final turn cross controlled stall.  

Much the same thinking went into the Twin Comanche getting a bad rep because the FAA wanted Vmc demos at low altitude to "impress" on the candidate the need for recovery

The FAA changed their mind and the Twinkie added 10 mph to the speeds way back when

Spins in proper aircraft are not a problem My Commercial Check Ride 60 years ago was with the local retired head of the GADO office and he had me do 4 spins (2R/2L) in my Cessna 140 and said that was good enough let's go home and signed me off. We went 1 turn in the spin and about 3/4s of one coming out. Didn't take it any farther. Used to do them in 150s also. NOT in any Mooney and not beyond about 1 1/2 turns. 

Bill Wheat made a believer out of me. He did things I would never have tried. I'm not test pilot material. 

 

[Pinecone]

On 7/13/2024 at 2:16 PM, dkkim73 said:

Took a bit to get used to the G1000's slip/skid indicator. A few including my transition instructor just pointed out the nose motion is a pretty good indicator. Now I'm really drifting the thread. 

That is still the best (or maybe second best) way to determining uncontrolled yaw.  I was taught this both in primary training and my initial aerobatic training and have taught it unusual attitude training.

You can also do it looking out at the wing tip.  If the tip appears to move forward and back, you are not controlling yaw.

Ok, the question on your mind is what is the best yaw indicator, that is a yaw string.  A simple piece of yarn attaced to the center of the windscreen.  Unfortunately, you can't use them on SE piston planes due the prop wash.  But they are used on glider and helicopters, and even some jets.