The Mooney Pull & Take Off Trim ???

[PT20J]

41 minutes ago, EricJ said:

In my experience it's pretty rare on Cessna 150s, 172s, etc., that the tail tie down ring is still round on the bottom.   

The local flight school got tired of replacing tie down rings and repairing rear bulkheads and installed these https://middleforkmods.com

Skip

[Shadrach]

12 hours ago, carusoam said:

My M20C’s tail tie down ring was flattened on the bottom…

Not sure if the spring could hit the ground with the ring in place….

But, the ring had an offset angle as if it had been modified/bent….  
 

The tail tie down ring is no ordinary eye-bolt….

Best regards,

-a-

That is interesting for sure as it appears to be geometrically impossible to do that without bending something.  The spring would have to hit first and either dig into the ground or bend substantially for the eye bolt to hit.

[DCarlton]

On 11/14/2022 at 9:53 PM, carusoam said:

See if your POH has descriptions for T/O and landing in X-winds…

Mostly… T/O in X-wind, the ground handling part gets adjusted, the T/O is nearly the same, the post rotation got discussed around here last week… (follow the extended centerline vs. follow the heading…)

The big difference… how much flap to use for X-wind landings… often T/O flaps are desired… because cross controlled rudder/ailerons are so draggy, full flaps add even more drag… avoid accidentally slowing before getting to the ground….

Keep in mind… when t/o flaps are used for landing…. Short field performance has left the discussion….   

Often, elevated X-winds aren’t very steady… this leads to approaching at a higher speed…. 1/2 the gust speed added…

 

Soooo… there is probably a calculated change to Vr with a cross wind…. But… our airspeed indicator keeps displaying what is happening relative to the wings…. Where it counts.

The important thing to consider with all winds… what changes as the plane leaves the ground and climbs past obstacles… including tree lines and buildings….

Departing into an increasing headwind is good…..

Turning away from a headwind can be terrible… without enough airspeed to handle the difference…

PP thoughts only,

-a-

I checked the '67 POH.  It's very sketchy and doesn't offer anything more than we've already discussed.  See attached.  I plan to experiment with the speeds and trim positions a bit more although I'm not optimistic that back pressure will be required if my trim is set to the TAKE OFF position.  It might if the speed is low enough; 65-70.  Will see.  

[carusoam]

Apply back pressure….

Is that the same as….  Pull gently?

Relax some back pressure…

Is that the same as control the attitude during the T/O?

 

T/O is interesting for the dynamics of so many changing variables….

-a-

[DCarlton]

17 hours ago, carusoam said:

Apply back pressure….

Is that the same as….  Pull gently?

Relax some back pressure…

Is that the same as control the attitude during the T/O?

 

T/O is interesting for the dynamics of so many changing variables….

-a-

We've beat this to death, but I'm starting to have fundamental questions for the aeronautical engineers.  How should a plane behave on the runway.  Should it fly off on its own without any back pressure whatsoever on the yoke?  Intuitively, that doesn't sound safe to me.  I'm guessing whatever state of take off trim its in should be rather neutral requiring some back pressure to become airborne.  I wouldn't think forward pressure on the yoke would be required to maintain a safe attitude either.  Having the elevators trail the horizontal stabilizer in a neutral position intuitively sounds correct to me.  Perhaps with bigger aircraft and bigger CG changes you might need some downward force on the tail to assist in takeoff.  At most you would kiss the runway for the entire length without any back pressure.  I'm sure someone knows the fundamentals.    

[Shadrach]

@DCarlton

I flew for a bit today. I was light at about 2100lbs.   It was windy (16G24) and right down the runway so I was flying final at a higher airspeed than usual.  My  take away is that speed has more effect on trim than I previously thought.  I did two approaches at 3/4 flaps and 80mias and trim was below take-off for the whole approach. Confident there is little to no difference between our airframes in terms of trim and trim indication.

[carusoam]

As far as flying off the runway goes…

The design engineers decide what speed that will happen at…

and adjust the gear length to make it happen…

 

Mooney decided to have the pilot initiate the take off…

Trainers seem to leave the ground on their own…

 

So many trade offs available when designing the plane

LBs have a taller nose gear than the mid bodies…

 

Watch out for transition to the long body…. The sight picture is a couple of degrees off…

Using the mid body sight picture… you might touch down on the nose wheel first…

 

PP thoughts only, not a plane designer…

Best regards,

-a-

[Pinecone]

You can experiment and see what works best for you.  Do a series of takeoffs with slightly more nose up trim for each and see what seems best.  And do so at different CGs.

Most light aircraft I have flown need a bit of back pressure to lift off at the "normal" speed.  If you don't apply back pressure, the eventually fly off on their own.  IIRC, the Aerostar is one that MUST have back pressure added, as the wing sits at a negative angle of attack with all 3 gear on the ground.

Jets, due to the swept wings, required you to rotate to a specific pitch attitude (thus Vr).

[Yetti]

flap people flaps.     If you land full flaps you will have more nose up trim.   If you land half flaps which seems to be my thing in the non spring time Texas windy gusty (none or half flaps in the spring) I am landing mostly half flaps.     Half flaps will put you about take off trim.   Full flaps will put you with lots of nose up trim.  In an F model   YMMV

[Hank]

32 minutes ago, Yetti said:

I am landing mostly half flaps.     Half flaps will put you about take off trim.   Full flaps will put you with lots of nose up trim.  In an F model   YMMV

All same same in my C, too. But I've noticed that Fs land much better with Full Flaps when it's not springtime gusty, whereas in my C I only use full flaps if I'm high or if the wind is calm. 

[Yetti]

1 hour ago, Hank said:

All same same in my C, too. But I've noticed that Fs land much better with Full Flaps when it's not springtime gusty, whereas in my C I only use full flaps if I'm high or if the wind is calm. 

full flaps makes you in not as good a position if you have to do a go around.    flaps don't land planes.  Pilots land planes.

[A64Pilot]

21 hours ago, DCarlton said:

We've beat this to death, but I'm starting to have fundamental questions for the aeronautical engineers.  How should a plane behave on the runway.  Should it fly off on its own without any back pressure whatsoever on the yoke?  Intuitively, that doesn't sound safe to me.  I'm guessing whatever state of take off trim its in should be rather neutral requiring some back pressure to become airborne.  I wouldn't think forward pressure on the yoke would be required to maintain a safe attitude either.  Having the elevators trail the horizontal stabilizer in a neutral position intuitively sounds correct to me.  Perhaps with bigger aircraft and bigger CG changes you might need some downward force on the tail to assist in takeoff.  At most you would kiss the runway for the entire length without any back pressure.  I'm sure someone knows the fundamentals.    

I’m no Aeronautical Engineer, but trim= airspeed, meaning if it’s trimmed for 80 kts, then when you approach 80 kts on the runway it will fly itself off, “in ground effect it will get off less than trim speed due to ground effect”, but not a whole lot less.

Power influences trim some, but flaps influence it more, to a great extent power causes more of a climb or descent than an increase or decrease in speed, but flaps change the center of lift, so we need big trim changes usually with flaps.

I very often am flying into shorter grass strips and want all the drag I can get to get down over the trees, so I wish we had more flap than we do, so I always land full flaps. If I’m caught out in gusty cross winds and there is enough runway then I’d back off on the flaps. Plus landing with full flaps means landing at a slower speed and why other than gusty winds wouldn’t you want that?

I assume the no or little flap people almost always fly off of long paved runways?

If you trim so that the airplane flies herself off, two things, one it may catch you off guard one day as it pops off before you expected it, and secondly pretty much as soon as your off the ground you running the trim down as she accelerates and especially when you raise flaps.

Now the crop duster that I have a bunch of time in I trimmed it so it would fly itself off pretty much, largely because the trim was a lever like the throttle so you could bump it and instantly make large trim changes, only had 15 degrees and takeoffs were made at almost twice the landing weight, so different airplanes are well different.

There is a crop duster / bush pilot “trick” For takeoffs match flap travel with full aileron deflection, the theory is the airplane manufacturer isn’t stupid and max aileron travel is about the point where you get the most lift with the least drag, more than that and drag increases faster than lift.

Seems to work for really overloaded / heavy aircraft.

[Hank]

1 hour ago, A64Pilot said:

I very often am flying into shorter grass strips and want all the drag I can get to get down over the trees, so I wish we had more flap than we do, so I always land full flaps. . . .

I assume the no or little flap people almost always fly off of long paved runways?

I got my license and based my Mooney for seven years at an obstructed 3000' field, and my normal takeoff has always been no flaps; when I'm loaded heavy then I use Takeoff Flaps. My normal landing over the trees, adding throttle to level off to clear them then going to idle, starts with Takeoff Flaps and is adjusted as needed along with throttle and trim,  and I touch down on the second stripe past the numbers. Trim is often near the Takeoff mark.

I've posted this before, but it's still about the only in-cockpit video that I have; thus is landing over the trees with Takeoff Flaps:

Now I'm at a 5000' field, the middle half has a strong gradient, and with no flaps I'm in the air while it's still flat and easily clear the rise. 

[Shadrach]

Meh.

More flaps = less speed = less energy.  I go into sub 2000 foot strips frequently. I can’t imagine why one would want to land with more energy than needed.

[PT20J]

21 minutes ago, Shadrach said:

Meh.

More flaps = less speed = less energy.  I go into sub 2000 foot strips frequently. I can’t imagine why one would want to land with more energy than needed.

Had an interesting conversation with an airline pilot buddy recently. His airline SOP is minimum flaps required for weight and field length. Less flaps = higher approach speed = less fuel burned on approach = $$$ savings. Tubojets burn a lot of fuel at low altitudes. Not really applicable at all to Mooneys, but I found it interesting nevertheless.

 

[Shadrach]

24 minutes ago, PT20J said:

Had an interesting conversation with an airline pilot buddy recently. His airline SOP is minimum flaps required for weight and field length. Less flaps = higher approach speed = less fuel burned on approach = $$$ savings. Tubojets burn a lot of fuel at low altitudes. Not really applicable at all to Mooneys, but I found it interesting nevertheless.

 

Very interesting. Makes sense when you’re configuring several miles out. Less drag = less power = less fuel burn.

[MikeOH]

1 hour ago, Shadrach said:

Meh.

More flaps = less speed = less energy.  I go into sub 2000 foot strips frequently. I can’t imagine why one would want to land with more energy than needed.

EXACTLY!

Energy is proportional to the SQUARE of speed; 10 percent fast and you have 20 percent more energy to dissipate.  Unless it's really blowing, I land with full flaps every time.  I can be down and stopped in 650 feet (1st turn off) if I really want to (heavy braking), normally I just exit at the second turn off at 1500 feet with little to no braking.  I've noticed that most light GA uses the third turn off at 2400 feet, including Cherokees and C172s, ...my conclusion is most approaches are way too fast, or not enough flap

[DCarlton]

For the full flappers out there, where in the pattern do you drop full flaps (the final notch)?  Are you operating out of a busy airport with a full pattern and jets on the straight in?  If so, how do you deal with a tower that often wants you to keep your speed up?  Thanks.

[EricJ]

44 minutes ago, DCarlton said:

For the full flappers out there, where in the pattern do you drop full flaps (the final notch)?  Are you operating out of a busy airport with a full pattern and jets on the straight in?  If so, how do you deal with a tower that often wants you to keep your speed up?  Thanks.

I usually go to full flaps turning final or a little after.

[WAFI]

Just now, DCarlton said:

For the full flappers out there, where in the pattern do you drop full flaps (the final notch)?  Are you operating out of a busy airport with a full pattern and jets on the straight in?  If so, how do you deal with a tower that often wants you to keep your speed up?  Thanks.

I'm based out of one of the busiest GA airports in South Florida and mostly land full flaps 90% of the time. I have never been asked to speed up but many times get ask to slow down. I try to keep my airspeed up to when I have to "report 3 miles out" to the tower but hardly make it there before getting asked to reduce speed. 98% of the time I fly a straight in approach from 10 miles out, where I make first contact with the tower.

When in pattern:

Drop gear - mid field down wind

half flaps - abeam the numbers

full flaps - base leg

Red, Blue, Green, Runway clean - On Final

 

Red: Mixture

Blue: Prop

Green: Gear X 2

Runway Clean: Clear to Land

[Shadrach]

1 hour ago, DCarlton said:

For the full flappers out there, where in the pattern do you drop full flaps (the final notch)?  Are you operating out of a busy airport with a full pattern and jets on the straight in?  If so, how do you deal with a tower that often wants you to keep your speed up?  Thanks.

I usually drop the first 1/4 shortly after dropping the gear (abeam the numbers or 2 miles out for straight in). The next 1/4 right after turning base. The next 1/4 right after turning final and then full flaps ~1/4 mile final. If I’m going into a short strip, I try to be fully configured a bit earlier.  For straight in approaches I drop final notch of flaps in the last 1/4 mile of final.  

Instrument approaches Are hold approach configuration (gear and takeoff flaps) until committed to land.

Going into large airports requires speed flexibility. I’ll fly final at whatever speed is asked but at 2 miles out, I need to be at or below 120mias to get the gear down. I can roll it on at high speed if needed, but still prefer to scrub as much energy as is practical before landing and set flaps appropriately.

If I find myself in the position of needing to go down and slow down, knowing you can’t do both initially,  I usually focus on getting the speed down.  The Mooney will sink like any other aircraft when on the backside of the drag curve and will descend at surprisingly steep angles at relatively flat pitch with the gear and flaps out. Not the kind of ops for non flying pax but then neither are forward slips. 

[rbp]

23 hours ago, Shadrach said:

For the full flappers out there, where in the pattern do you drop full flaps (the final notch)?  

I will only put full flaps in if the nose is within 90 degrees of the runway heading (eg base or final). With gear and full flaps, there's simply too much drag.

On a straight in, I put full flaps in at 1000' AGL because I find that long stabilized approaches make for more consistent landings. 

[DCarlton]

Appreciate the additional discussion.  At CRQ, it seems like there's usually 3-5 planes waiting to take off and jets on the straight in.  The tower rarely wants you to slow down unless they ask you to fly a 360 on downwind for traffic spacing.  The last time I flew the ILS in VFR conditions on a busy day, I asked the tower if they minded if I slow down;  I wanted to fly the entire approach configured for landing but also wanted to know if there was a jet crawling up my tail beacon.  They said they would prefer I didn't.  In the pattern, downwinds are most often extended so I rarely drop gear and then take off flaps until I turn base.  Then I add another pump to 3/4 flaps on final.  So....  I'm guessing all of this influences your flying habits including flying off of a 5000 ft near sea level runway for 30 years.  However...  after all the full flap shaming I'm going to try adding that last pump of flaps on short final on VFR days (and see if the tower complains that Mooneys are too slow).  :> 

[Will.iam]

On 11/18/2022 at 9:10 PM, PT20J said:

Had an interesting conversation with an airline pilot buddy recently. His airline SOP is minimum flaps required for weight and field length. Less flaps = higher approach speed = less fuel burned on approach = $$$ savings. Tubojets burn a lot of fuel at low altitudes. Not really applicable at all to Mooneys, but I found it interesting nevertheless.

 

Also less noise as engines are at lower power settings and against intuitive logic like steel brakes, there is less brake wear on carbon brakes when you heat them up in one continuous brake application. So by landing at a higher speed energy state you  absorb more heat energy and thus lower brake wear. 
 

[Will.iam]

If you land with full reversers and then use the brakes to slow down to taxi speed from approximately 80 or 70 knots when you stow the reversers you wind up with the brakes only getting to about 180 to 200 degrees or maximum wear of the brakes.  We were going through a lot of brake pads until ops showed us the data and changed our braking policy.