Takeoff trim

[bonal]

Hmmm lets see, for take off I go 2 pumps flaps out of 4 check visually out window (don't pay much attention to indicator since I see them deploy) trim is set for about half a bar width above the take off indication.  Rotation at 75mph to 80 mph depending on temps and GW. gear comes up as soon as I can tap the brakes and flaps follow as soon as positive rate.  My trim setting seems to leave me at around 110mph with no pressure on yoke. As for the other end I never think to look at my trim setting if I have the space for a long descent I will trim and power for around 300fpm and as close to Vne as I can get.  After gear speed and then flap speed again I don't pay much attention to the indicator as I trim for airspeeds DW100 B90 F80 with no touch on the yoke.  Landing flaps for me are guided by how much cross wind there is and I don't worry too much about no flaps if there is at least 2500ft of pavement available.  So I guess My ASI is as much a trim indicator as my trim indicator

[Mooneymite]

17 minutes ago, bonal said:

 So I guess My ASI is as much a trim indicator as my trim indicator

So....after you land, where is the trim indicator on an average day?  Even though I don't pay much attention to it while flying, I notice that it is consistently the same spot after I land.

[Bob_Belville]

18 minutes ago, bonal said:

Hmmm lets see, for take off I go 2 pumps flaps out of 4 check visually out window (don't pay much attention to indicator since I see them deploy) trim is set for about half a bar width above the take off indication.  Rotation at 75mph to 80 mph depending on temps and GW. gear comes up as soon as I can tap the brakes and flaps follow as soon as positive rate.  My trim setting seems to leave me at around 110mph with no pressure on yoke. As for the other end I never think to look at my trim setting if I have the space for a long descent I will trim and power for around 300fpm and as close to Vne as I can get.  After gear speed and then flap speed again I don't pay much attention to the indicator as I trim for airspeeds DW100 B90 F80 with no touch on the yoke.  Landing flaps for me are guided by how much cross wind there is and I don't worry too much about no flaps if there is at least 2500ft of pavement available.  So I guess My ASI is as much a trim indicator as my trim indicator

Uh huh. So, you just landed, short field, no wind, so you used full flaps and trim to as slow as possible for touch down - let's say 1.2 x Vso = 68 mias.

Now before you touch the trim wheel, where is it? (In my E is would be against the UP stop.) 

[bonal]

I usually touch down at 75mph and it almost always takes 3 pushes on the wheel to get back to starting point.  next time I will try to remember to see how many pulls to reach to up stops after I've landed because once I'm safely on terra firma I have never checked to see how much trim I still have available. I do know that I have never hit the stops setting for landing. And as for landing flaps I go with take off setting. When I was trying to learn to slow down to make the stall on flare and on full flaps I was pulling in on the prop and when I cut power dropped bounced and went full power for the go and the nose came up so violently almost lost the airplane (see thread worst landing ever)  I know my procedures are most likely not up to your airline standards but I also know I can get in tight between mountains trees onto really short narrow strips.  my wife is very comfortable with my flying and that is most important judgment to me. we discuss after every landing.

[Marauder]

How about in flight trim location while in cruise? Mine sits almost completely in the "nose down" position.

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[DXB]

Just now, Marauder said:

How about in flight trim location while in cruise? Mine sits almost completely in the "nose down" position.

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Mine too.  Occasionally I've run out down trim in cruise.   Have had several instances of it in descent.   Have never come close to running out of up trim.  Abnormal? Needs adjustment?

[Marauder]

Just now, Marauder said: How about in flight trim location while in cruise? Mine sits almost completely in the "nose down" position.

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Mine too.  Occasionally I've run out down trim in cruise.   Have had several instances of it in descent.   Have never come close to running out of up trim.  Abnormal? Needs adjustment?

Don't know. Never paid much attention to it until I was on a long trip with autopilot on and saw it that way. I usually don't descend too aggressively so never saw an indication that I had run out of trim.

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[Hank]

I've never run out of trim. Next trip beyond the pattern I'll check and take pitchers in cruise. I descend at 500 fpm, trimmed hands off, typically just below the 175 mph yellow but sometimes 180-185 mphi.

Going into a 2000' grass strip, I was always more concerned about weight (2 people, half tanks max) and keeping airspeed exactly on target (90 downwind & base, 85 final slowing to 70 just before flare). Flaps and trim, along with throttle, elevator and ailerons, were put wherever they needed to go to put me over the snow fence and into the grass with minimal float. Landing to the south was more exciting, had to clear the cement factory's gravel pile on final; the jump plane didn't do that once . . .

Temos vary, DA varies, landing weight varies, runway length/surface/slope vary, wind direction and speed vary, so my flight control positions vary. Speed on final varies only a little bit with weight. 

[Shadrach]

Something weird is going on.  Both Bob and I use all of our nose up trim on final (depending on load) mine is a mid-body his is a short body.  Mite, Dev and Chris with a sample of the same airframes are experiencing the opposite.  I wish Mr. Wheat were still with us, this is exactly the kind of question that he was uniquely qualified to answer.

[jamesm]

I have put a  sharpie mark Horizontal stabilizer and  match  the mark to the paint lines fuselage,  so during pre-flight I can tell if the trim is set for take-off or not.  Like the Big boys do.

I am half tempted to put a string  potentiometer to make stab trim indicator digital read out.

James '67C

 

Edited August 19, 2016 by jamesm

[TheTurtle]

Man there is a ton of great info in this thread.  Lots to go look at now.  I flew yesterday and gave it a little less up trim and started pulling lightly at 65mph and thing felt much smoother.  We went up to big bear with 9000DA and actually circled leaving before the ridge just to be safe.  Its was bumpy as hell.  Left way to late in the day but the dang plane wouldnt start so grabbed some lunch and went back to it.  Coming home was a rush.  All downhill in the yellow arc as soon as we hit smooth air.  I noticed that I ran out of down trim as I was trying to keep it around 500fpm.  Nearly 200mph ground speed.  !!  thats why I bought this thing right!  Shes definitely a squirlly bird in the bumps though.  Seems to have a lot of tail wag.

[Andy95W]

The stop block noted in the picture below is also where the indicator wire attaches (other photo).  I've seen some that people had tried to adjust the indicator by adjusting the stop block on the threaded shaft, which of course also changed the stops themselves.

[mooniac15u]

1 hour ago, Shadrach said:

Something weird is going on.  Both Bob and I use all of our nose up trim on final (depending on load) mine is a mid-body his is a short body.  Mite, Dev and Chris with a sample of the same airframes are experiencing the opposite.  I wish Mr. Wheat were still with us, this is exactly the kind of question that he was uniquely qualified to answer.

Are some of you trimming on final and not touching the trim during flare and touchdown while others are trimming for touchdown?  It seems like the first group should not run out of trim and the second might. 

[Shadrach]

1 hour ago, mooniac15u said:

Are some of you trimming on final and not touching the trim during flare and touchdown while others are trimming for touchdown?  It seems like the first group should not run out of trim and the second might. 

I cant imagine trimming for touchdown. I trim for upon turning final and then maybe one more time on short final. 99% of my landings are full stall with a very pronounced flare (done with the yoke), elevator is full nose up after mains touch, nose gear gently touches a few hundred feet later.  

[MyNameIsNobody]

3 hours ago, Shadrach said:

Something weird is going on.  Both Bob and I use all of our nose up trim on final (depending on load) mine is a mid-body his is a short body.  Mite, Dev and Chris with a sample of the same airframes are experiencing the opposite.  I wish Mr. Wheat were still with us, this is exactly the kind of question that he was uniquely qualified to answer.

When I go full flaps on final I am rolling in a bunch of nose up trim.  Yes, this is weird.

[MyNameIsNobody]

4 hours ago, Hank said:

I've never run out of trim. Next trip beyond the pattern I'll check and take pitchers in cruise. I descend at 500 fpm, trimmed hands off, typically just below the 175 mph yellow but sometimes 180-185 mphi.

Going into a 2000' grass strip, I was always more concerned about weight (2 people, half tanks max) and keeping airspeed exactly on target (90 downwind & base, 85 final slowing to 70 just before flare). Flaps and trim, along with throttle, elevator and ailerons, were put wherever they needed to go to put me over the snow fence and into the grass with minimal float. Landing to the south was more exciting, had to clear the cement factory's gravel pile on final; the jump plane didn't do that once . . .

Temos vary, DA varies, landing weight varies, runway length/surface/slope vary, wind direction and speed vary, so my flight control positions vary. Speed on final varies only a little bit with weight. 

Just so you aren't drinking pitchers while in cruise...or fielding what they throw...

[Marauder]

Man there is a ton of great info in this thread.  Lots to go look at now.  I flew yesterday and gave it a little less up trim and started pulling lightly at 65mph and thing felt much smoother.  We went up to big bear with 9000DA and actually circled leaving before the ridge just to be safe.  Its was bumpy as hell.  Left way to late in the day but the dang plane wouldnt start so grabbed some lunch and went back to it.  Coming home was a rush.  All downhill in the yellow arc as soon as we hit smooth air.  I noticed that I ran out of down trim as I was trying to keep it around 500fpm.  Nearly 200mph ground speed.  !!  thats why I bought this thing right!  Shes definitely a squirlly bird in the bumps though.  Seems to have a lot of tail wag.

Rest your feet on the rudders when it is bumpy.

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[Marauder]

Something weird is going on.  Both Bob and I use all of our nose up trim on final (depending on load) mine is a mid-body his is a short body.  Mite, Dev and Chris with a sample of the same airframes are experiencing the opposite.  I wish Mr. Wheat were still with us, this is exactly the kind of question that he was uniquely qualified to answer.

It might have something to do with CG and what we have in the plane. I usually have about 50 pounds of stuff in the baggage area.

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[kpaul]

Another thought; is this the difference between using electric trim and manual trim?  It is easy to continue to trim through the flair with electric trim vs reaching down for the manual trim.

[MyNameIsNobody]

15 hours ago, Marauder said:

It might have something to do with CG and what we have in the plane. I usually have about 50 pounds of stuff in the baggage area.

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I usually have at least 50lbs in baggage too.

[Danb]

But Chris's loads are usually quite heavy.

[Shadrach]

1 hour ago, Danb said:

But Chris's loads are usually quite heavy.

I realize now that his running out of nose down trim comments are probably one big set up to post some pics of his "passengers"...

[gsxrpilot]

If you've successfully launched and landed more than 10 times, then the first thing you should do is ignore the POH or Owners Manual and just fly what feels right.

I use more take-off trim if I'm using flaps and less if I'm not using flaps. But regardless, push all the knobs full forward, and as soon as you're off the ground, raise the gear.  Now with the gear tucked up, figure out what you want to do with trim, flaps, rate of climb, boost pump, etc.

I'd always leave the power, prop, mixture full in unless it was hot and I had cooling issues. The first control to move for cooling is the prop. Back the RPM's down to 2500 and leave everything else full in. That usually keeps the C cool enough.

On landing, I'm with Shadrach and Bob. If I'm coming in slow and steep with full flaps, I'll use full up trim. If no flaps with a long runway, I'll use a lot less trim.

It's a simple airplane, just fly it the way it feels right and behaves well. And feel free to ignore the book.

[MyNameIsNobody]

Thank you.  I will take that advise.

[Guest]

Mooney should have never dropped the trim/flap inter connect that is in the M18 Mite.

Clarence