Takeoff Trim Setting - New to me 1970 M20F

[Utah20Gflyer]

20 hours ago, AndreiC said:

I was told that many people set their trim indicator so its *bottom* edge (it is a white square in my plane, probably in yours as well) lines up with the *top* of the trim position marked on the window. You could try that to get a more nose-up trim position. But YMMV; I tried this in my plane and did not like it, so I reverted to getting the trim indicator properly aligned with the mark on the side.

This is my standard procedure.  Take off trim is slightly higher than the mark.   It only requires a modest pull on the yoke to rotate and lift off the runway.  
 

With you and an instructor in the plane you are going to be fairly forward CG (although still well within limits) So a little extra nose up trim will help counteract that.  Not a big deal and not worth taking things apart.   With a different CG the standard mark may be correct.   Ie more aft CG and no flaps.  

[McMooney]

My IR instructor suggested i not bother with the flaps, one less thng to do.   Tried it, took off in the same distance and except for soft/short fields, i never bother anymore.

trim, white block to white block,  it's actually the same position for approach, not sure hwo that happened

[RescueMunchkin]

My 67 F is the opposite - I have to trim down quite a lot after takeoff (take-off trim indicated, 2 pumps of flaps - half extended to take-off setting), then trim nose down much more after retracting flaps.

Edited August 21, 2024 by RescueMunchkin

[Fritz1]

takes a little experimenting with various CGs, I crank in the minimum amount of up trim that allows me to rotate comfortably so I need less down trimming when the gear comes up and the flaps come up

[Shadrach]

31 minutes ago, RescueMunchkin said:

My 67 F is the opposite - I have to trim down quite a lot after takeoff (take-off trim indicated, 2 pumps of flaps - half extended to take-off setting), then trim nose down much more after retracting flaps.

Same.

Positive rate, Gear up, swipe forward 

Flaps up <100MIAS, swipe forward

pitch for cruise climb 120MIAS, swipe forward.

[RescueMunchkin]

@ProtoFly when you trim for full flap landing (75-80mph), where do you find your trim at?  My landing trim is exactly my marked take-off trim

Edited August 21, 2024 by RescueMunchkin

[Shadrach]

13 minutes ago, RescueMunchkin said:

@ProtoFly when you trim for full flap landing (75-80mph), where do you find your trim at?  My landing trim is exactly my marked take-off trim

That should depend on weight.  I’ve run the trim into the full nose up stop on short final with the front seats filled and ~12 gals remaining in one tank. I Rarely fly with less than 2hrs on board but it’s happened a time or two.

[Hank]

1 hour ago, RescueMunchkin said:

@ProtoFly when you trim for full flap landing (75-80mph), where do you find your trim at?  My landing trim is exactly my marked take-off trim

I have about 10 or so hours in a 1975 F. My standard landing in my C is Takeoff Flaps, adjusted as required on final, but usually small adjustments (the Up / Down toggle moves the flaps as long as I hold it, letting go stops the movement at any point), but my first F landing that way wasn't good. My 2nd landing was with Landing Flaps after turning final, and it was great. 

Maybe it was the added fuselage length and different CG. Maybe it was the three-position Flap lever (Up, Takeoff, Landing--no ability to stop anywhere else).

All I know is my subsequent F landings were much better with Landing Flaps. But I still routinely land my C with Takeoff Flaps.

[RescueMunchkin]

35 minutes ago, Hank said:

I have about 10 or so hours in a 1975 F. My standard landing in my C is Takeoff Flaps, adjusted as required on final, but usually small adjustments

No experience in a short body, but my post was to find out what trim position his indicator shows when trimmed for final to help judge the indications.

I have hydraulic flaps which you can only really adjust when deploying based on number or pumps, retracting is a toggle. Full flaps for me is about 3.8 pumps and I'm always having to trim nose up after extending flaps at all.

[MikeOH]

WARNING!  Thread creep:

All this talk of flaps...my favorite was the M20B I used to rent: mechanical flaps

No motors, wiring, limit switches, fuses, hydraulic pump, leaky seals, valves, bleeding air, jackscrews....

Just reach over and put the flaps where you want them as fast as your hand can move!!  Mooney should have just left them that way, IMHO.  But I guess customers wanted complexity and gadgets....

[Barneyw]

4 hours ago, Shadrach said:

Some time at a safe altitude with take off flaps deployed and the airplane trimmed for hands off climb at Vy, try raising flaps without trying to making pitch adjustments.  It is not so dramatic as it is while managing an accelerating aircraft in the airport environment.

I have done more than a few full flap, touch and goes and even the pitch change during the transition from full flaps to no flaps is quite manageable though the procedure is not something I'd recommend.  It's a fair amount of work coordinating pitch, initial trim, gear retraction, flap retraction and retrim at low speed.

It is a bit of a handful especially if you have manual gear. This sort of flying gymnastics plays out in particularly while conducting a missed approach in anger which is why it has been suggested from our group that the the maximum flap setting for an instrument approach be limited to take off flap and if you break out at a low minima land without changing configuration. Just wondering how many people here practice landing with take off flap or even practice flapless landings and what is their experience? I haven't had a chance yet. How do people fly instrument approaches? One last thing I don't think the AFM has an option of taking off at flaps zero so I think philosophically speaking it's bad procedural advice from any instructor to arbitrarily change the written word unless of course Mooney have issued a supplement allowing this.

[Shadrach]

1 hour ago, Barneyw said:

It is a bit of a handful especially if you have manual gear. This sort of flying gymnastics plays out in particularly while conducting a missed approach in anger which is why it has been suggested from our group that the the maximum flap setting for an instrument approach be limited to take off flap and if you break out at a low minima land without changing configuration. Just wondering how many people here practice landing with take off flap or even practice flapless landings and what is their experience? I haven't had a chance yet. How do people fly instrument approaches? One last thing I don't think the AFM has an option of taking off at flaps zero so I think philosophically speaking it's bad procedural advice from any instructor to arbitrarily change the written word unless of course Mooney have issued a supplement allowing this.

I have manual gear. My father in law (also a pilot) teases me that all the knob turning and lever pumping makes it look like I’m running a steam engine during approach and take off.

[Barneyw]

3 hours ago, Shadrach said:

I have manual gear. My father in law (also a pilot) teases me that all the knob turning and lever pumping makes it look like I’m running a steam engine during approach and take off.

So the AFM should read minimum crew 2 - 1 x  Pilot, 1 x Stoker 

[ProtoFly]

13 hours ago, RescueMunchkin said:

@ProtoFly when you trim for full flap landing (75-80mph), where do you find your trim at?  My landing trim is exactly my marked take-off trim

I'm at full trim nose up, with two people front seats and between full and half-tanks.  Some back pressure in ground effect until she touches down gently on the mains, then nose.

Reading through all the responses, and the consensus seems to be that there's no consensus - fly the plane :-) When it goes in for its first annual, I'll get all the rigging checked.  Meanwhile, it's getting new sneakers and some LED's.....

[ArtVandelay]

When trimmed neutral my Js elevators are in the cruise position (slightly downward).

[Shadrach]

2 hours ago, ProtoFly said:

I'm at full trim nose up, with two people front seats and between full and half-tanks.  Some back pressure in ground effect until she touches down gently on the mains, then nose.

Reading through all the responses, and the consensus seems to be that there's no consensus - fly the plane :-) When it goes in for its first annual, I'll get all the rigging checked.  Meanwhile, it's getting new sneakers and some LED's.....

I only hit the stop on short final if I’m at min fuel with two up front. This is a function of two things:

1) A forward CG

2) Very low approach speed at <2200lbs. Usually down to 65MIAS by short final.

The combined effect is:

Less airspeed requires an increase in AOA

Increase in AOA requires more elevator input. 

Forward CG requires more elevator to increase AOA.

Less airspeed makes elevator elevator less effective requiring more input.

All in all, I think the plane is pretty well balanced across its weight, cg and speed envelope.  Why not add a 50lbs ballast to the baggage compartment?

[EricJ]

13 hours ago, MikeOH said:

WARNING!  Thread creep:

All this talk of flaps...my favorite was the M20B I used to rent: mechanical flaps

No motors, wiring, limit switches, fuses, hydraulic pump, leaky seals, valves, bleeding air, jackscrews....

Just reach over and put the flaps where you want them as fast as your hand can move!!  Mooney should have just left them that way, IMHO.  But I guess customers wanted complexity and gadgets....

My hangar neighbor has an M20A that has manual flaps as well.    He likes them, too.    It makes me wonder why they switched to hydraulic.

[N201MKTurbo]

2 minutes ago, EricJ said:

My hangar neighbor has an M20A that has manual flaps as well.    He likes them, too.    It makes me wonder why they switched to hydraulic.

The same reason people change to glass panels and LED lights. Airplane owners always want the new and improved modern stuff.

[MikeOH]

1 hour ago, N201MKTurbo said:

The same reason people change to glass panels and LED lights. Airplane owners always want the new and improved modern stuff.

New, no doubt...but I'm not seeing where the "improvement" was with moving away from mechanical flaps??  I guess "new" and different is all it takes...

[Barneyw]

4 hours ago, Shadrach said:

I only hit the stop on short final if I’m at min fuel with two up front. This is a function of two things:

1) A forward CG

2) Very low approach speed at <2200lbs. Usually down to 65MIAS by short final.

The combined effect is:

Less airspeed requires an increase in AOA

Increase in AOA requires more elevator input. 

Forward CG requires more elevator to increase AOA.

Less airspeed makes elevator elevator less effective requiring more input.

All in all, I think the plane is pretty well balanced across its weight, cg and speed envelope.  Why not add a 50lbs ballast to the baggage compartment?

Protofly

Shadrach's suggestion is a good one and I always fly with a 20 litre (about 5gals) container of water permanently in the back which can be filled and emptied on demand. It's mainly there for two up flying and if you fill the back seats you can empty it.

[RescueMunchkin]

5 hours ago, ProtoFly said:

I'm at full trim nose up, with two people front seats and between full and half-tanks.  Some back pressure in ground effect until she touches down gently on the mains, then nose.

Reading through all the responses, and the consensus seems to be that there's no consensus - fly the plane :-) When it goes in for its first annual, I'll get all the rigging checked.  Meanwhile, it's getting new sneakers and some LED's.....

My F is at takeoff trim for full flap landing so there seems to be a significant difference in how our two planes fly.  I also have a Rajay like you. I fly with a sidewinder powered tow thing in my baggage compartment but don't find any difference in my trim settings whether I am solo or have an adult in front. Never flown with back seat passengers yet.

[RescueMunchkin]

Wanted to add that being at trim limits during normal operations does not sound "correct" to me and I would want to check in with an experienced Mooney mechanic.

 

I'll try to get pictures on my next flight of my trim indicator at takeoff and descent, see if you can post yours for comparison.

[cliffy]

C model- fwd CG and trimmed on final at about 70 mph to the flare -  When taxiing out for T/O it takes about 1/2 turn nose down for T/O trim

to be acceptable for me.

Many Mooneys have their pitch system rigged incorrectly.

It takes jacks to level the airplane and correct tools to rig the pitch system correctly.

Especially rigging the spring bungees for the correct elevator up position when the stabilizer is set to the proper LE down angle.

Not many shops know how to rig the pitch system on a Mooney.  Maybe I'll make a utube on it sometime. 

Just as a word of warning- IF the pitch trim is set full nose down on takeoff the nose wheel will never leave the ground.

There's not enough elevator force at full up to lift the nose in that condition 

Several Mooneys have suffered this fate and run off the end of a runway at high speed. 

[Fly Boomer]

5 minutes ago, cliffy said:

Just as a word of warning- IF the pitch trim is set full nose down on takeoff the nose wheel will never leave the ground.

And, conversely, if the pitch trim is set full nose up on takeoff (quite likely if not re-trimmed after landing) with full power and flaps up, the airplane may be uncontrollable.  At least one crash that I know of appears to have suffered this fate.

[cliffy]

Yes SO the moral of the story is?

Make sure your pitch trim is set up correctly by someone who knows what he is doing. 

Quit guessing at settings and do it right.