Jump to content

Moved from “One who will” to “One Who Has”


Recommended Posts

What you may expect when leaving the trim near full up....

The plane will wander off the ground on its own, while still going slowly...

Flying too soon, leaves you very close to the stall... any change in headwind as you come off the ground can be disastrous...

 

This is when your trim and indicator are both matching factory recommendations....

If your indicator is amiss... this wouldn’t apply...

 

Make sure your ASI is telling the truth...  and stall actually occurs at the speed predicted in the POH...

Nothing like coming off the ground and hearing the stall horn blare... as you gently hold back on the yoke...

The misplaced trim makes the gentle pull do something that it normally takes a much stronger pull to do...

Somewhere is a factory description for how much force is required to lift the nose wheel at Vr...

PP thoughts only... not a CFI...

Best regards,

-a-

  • Like 1
Link to comment
Share on other sites

  • 2 weeks later...

Hesitant to post as I’m the new guy, but you shouldn’t shoot an approach with a lot of up trim, the reason is the reaction you’ll get on a go-around.

I learned this on my Maule, a STOL airplane that full up trim makes for a nice slow approach with little force on the yoke, but with over 20 feet of 48 degree flaps and an IO-540 in the nose when you go to full throttle for a go around, it takes both hands to keep the nose down, or you will stall.

The biggest reason it’s so bad on a go around is the force of the airflow from the engine at full throttle adding to the elevator force, an aircraft on a slow approach the airflow over the elevator is much less than it will be when the motor is at full throttle.

So I now shoot an approach having to hold some back pressure, that way when the dog or whatever runs out on the runway in front of me, I can go to full throttle without it being so much of an effort.

Now while not applicable to a Mooney, but in a normal airplane with an elevator trim tab, going full up actually reduces the total up elevator available, the reason is your driving that tab full down, and that reduces the surface area of the elevator.

Link to comment
Share on other sites

11 hours ago, carusoam said:

Thanks for the additional details and insight A64...

What is the typical airspeed range on final approach for the Maule with the IO540?

Best regards,

-a-

I hate to say it depends, but it does, my early model M6/235 would hang on the prop at an airspeed that the airspeed indicator didn’t indicate, I believe due to the extreme nose up attitude, it also had pretty much zero aileron effectiveness at that speed, if a wing dropped, only the rudder would lift it. That was fixed with later model M6’s and subsequent Maule’s with ailerons that were 6” longer. VG’s helped aileron effectiveness greatly, but did little else except slow you down slightly

‘Anyway if you were trying to get in short, about 30 mph and you had a steep descent, elevator would not arrest the descent either, it took a little throttle to blow enough air over the rudder to raise the nose or you would land hard, hard enough to break something.

‘You could easily get stopped before the end of the numbers on a runway if you were light and zero wind, you could also get airborne before the end of the numbers too.

The problem if you will with a Maule is fuel consumption, the MPG for my Maule was identical to the C-210L that I flew at about 10 NM per gallon, the 210 was 20 kts faster and could carry a lot more though, and if kept light a surprisingly good STOL airplane.

It appears at first glance that my M20J’s fuel consumption is about 10 GPH at 155 kts giving of course 15.5 NM per gallon, butI’ve only had it a few days so not sure. I know I can slow down and likely get 20 MPG?

Normal approach speed was if memory serves was about 50 MPH on short final, chop power and a Maule with flaps out glides about like a short wing Piper, that is to say drop a coke bottle out of the window to see where your going to land.

On edit, a 235 Maule’s fuel consumption is actually lower than a 180 if flown at identical speeds, the reason is your power is so low on the 235 that you can very aggressively lean it out, and real world the 235 actually adds to useful load, a Maule’s actual ability to carry things is based on CG, and the heavy motor will allow more weight in the cabin before you get to stick force neutral point.

A Maule has  huge overlapping doors, think old station wagon and can carry large awkward things because you can get them into the airplane 

C0B68C0C-FEA7-455D-AA7E-43337795BBEA.jpeg

E51281D6-42CD-4129-8385-93E83D556415.jpeg

Edited by A64Pilot
  • Like 1
Link to comment
Share on other sites

  • 1 month later...
23 minutes ago, bluehighwayflyer said:

I do make a habit in the Mooney of setting trim for takeoff after landing and then checking it again before takeoff.  A side benefit is that doing this gets the yoke farther forward and makes it a little easier to get in and out of the plane.  

In my C, I usually land with the trim set pretty close to the Takeoff mark. I adjust it for hands-off 85 moh in final, and as I slow down just ease the yoke back a tiny bit. It's not worth trying to nudge the trim wheel all the way to touchdown. 

Link to comment
Share on other sites

On 2/11/2021 at 2:08 PM, Nukemzzz said:

My E is always on max nose up trim...  this might be because the combined weight of my instructor and I is 500lbs...but I'm not so sure.  

In all seriousness, setting up for cruise I roll the trim back a half turn, maybe one turn, then its back to full nose up on landing and just leave it full up for takeoff.  Does this seem normal to you?  Below is my loaded W&B for our training flights.  I just had the plane weighed in December.  I guess I'm questioning if my CG is further forward than I think.  I would have thought that one would run out of nose up trim at the Fore CG Limit.

 

WB.thumb.png.a54c6d93cebf45361448a3f5c9325ec3.png

@Nukemzzz I didn't see a direct answer to your question so I'll offer my unqualified thoughts on the matter.

Full nose up trim for takeoff would seem to indicate you are approaching your elevator control power limits for rotation which shouldn't happen when you're operating inside the CG envelope. I think something isn't quite right. I recommend calling an MSC and ask them the question, most are more than happy to provide this kind of info.

You are close to the forward CG limit for the gross weight at which you are operating so while I wouldn't expect full nose up for takeoff I would expect more nose up trim than the T/O trim point on the indicator as Hank mentioned in his C. Have you been able to compare notes with other E model drivers as to what they set for takeoff trim with similar loading? You mentioned rolling the trim a turn or so in cruise which sounds reasonable, but is the indicator still more nose up than the marked takeoff trim setting? Typically cruise trim indication will be below the takeoff trim mark even at full gross.

Barring confirming input from other M20E aircraft takeoff settings and if you're confident in your weight and balance data from your recent aircraft weigh, you may want to have the horizontal stab trim rigging checked to see if it is out of whack or indicating improperly. An MSC will be able to tell you if this is a good idea or not.

I'm really interested to hear what you find out.

Cheers,
Rick

  • Like 1
Link to comment
Share on other sites

7 hours ago, Junkman said:

@Nukemzzz I didn't see a direct answer to your question so I'll offer my unqualified thoughts on the matter.

Full nose up trim for takeoff would seem to indicate you are approaching your elevator control power limits for rotation which shouldn't happen when you're operating inside the CG envelope. I think something isn't quite right. I recommend calling an MSC and ask them the question, most are more than happy to provide this kind of info.

You are close to the forward CG limit for the gross weight at which you are operating so while I wouldn't expect full nose up for takeoff I would expect more nose up trim than the T/O trim point on the indicator as Hank mentioned in his C. Have you been able to compare notes with other E model drivers as to what they set for takeoff trim with similar loading? You mentioned rolling the trim a turn or so in cruise which sounds reasonable, but is the indicator still more nose up than the marked takeoff trim setting? Typically cruise trim indication will be below the takeoff trim mark even at full gross.

Barring confirming input from other M20E aircraft takeoff settings and if you're confident in your weight and balance data from your recent aircraft weigh, you may want to have the horizontal stab trim rigging checked to see if it is out of whack or indicating improperly. An MSC will be able to tell you if this is a good idea or not.

I'm really interested to hear what you find out.

Cheers,
Rick

Thanks for the feedback. It’s what I was concerned about as well. However, I can report that I no longer use full nose up trim on takeoff and it’s still just me and the instructor. Three things I think are going on:  1.  It’s no longer winter and I can actually trim further...I think it felt like max nose up but wasn’, 2. The plane is back flying often to the trim screw is freed up more and I wasn’t actually getting full nose up before, 3.  The trim indicator seems to be off. Starting from full nose up, it takes 5 pulls of the wheel (not turns) and then the indicator starts to read. And this is what I’ve been using for takeoff when coming off of a landing. I need to take some time and work it stop to stop and see where the indicator really is. 
 

So it seems to be ok, but not without quirks. 

  • Like 1
Link to comment
Share on other sites

From the outside...

You can get a feeling for full up and full down trim is... a good visual image.   Share a pic if desired...

Often, the trim indicator gets broken before the new owner arrives...

It should have continuous motion...

Take good notes... in this case a squawk sheet...

At annual... a simple cable replacement is easy and low cost... trying to do it mid year... includes too many hours of removing and replacing... at a high dollar cost...

It is important to have the full motion...

Not so important to see it on the needle inside the cockpit...  (nice to have)

PP thoughts only, not a mechanic...

Best regards,

-a-

  • Like 1
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.