Takeoff Trim

Jim K

Jim K

Final Approach
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Reading the beechtalk thread on the KSLE Bonanza fatal a few days ago... several posters mention that a large trim change is required during transition from landing to go-around. They were saying that going full power without re-trimming will produce a large pitch up and stall.

This seems foreign to me; all my time is in Cherokees, which will pretty much fly a set speed for a set trim position regardless of power. Cram the power in at Vref and it turns into a Vx climb.

Is this particular to v-tails? Other makes & models?
 
Jim K said:
Reading the beechtalk thread on the KSLE Bonanza fatal a few days ago... several posters mention that a large trim change is required during transition from landing to go-around. They were saying that going full power without re-trimming will produce a large pitch up and stall.

This seems foreign to me; all my time is in Cherokees, which will pretty much fly a set speed for a set trim position regardless of power. Cram the power in at Vref and it turns into a Vx climb.

Is this particular to v-tails? Other makes & models?
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The J on short final is almost at full nose up trim. Put in full power for go around and one needs Popeye arms to keep the nose down until you can get the trim off. A better go around strategy (when there is room) with the Mooney is to add enough throttle to arrest descent, fly level while you get the trim and flaps back to takeoff position, then throttle up and climb out.
 
it's a big thing on mooneyspace as well. while it's true that it takes a good push on the yoke for a go-around, I don't understand why it's so difficult to do. you, uh, push a little, BFD. yeah, retrim as part of the go-around, not sure why all of a sudden trimming or using 1/100th of your muscle power to push the yoke a bit forward is such a difficult thing. you could do partial power like bill mentioned, but the end result is the same...power or partial power, push the yoke, re-trim....it's the same process. now on go-around if you firewall it then sit there and do absolutely nothing, yeah, you're gonna pitch nose high pretty quick and be in big trouble. so, like, don't do that.
 
(It’s not takeoff trim but go-around trim that is being discussed I believe)

Trainers are setup so full power with landing flaps and trim is easily manageable.

Though the relationship between trim and airspeed is generally maintained through power changes in all normally configured aircraft, different aircraft may require more ‘coordination’ to keep control pressures down and deck angles reasonable in a go-around.

Full landing flaps in my Maule required a lot of (too much) forward pressure when full power was applied, at least until some of the flaps were bled off.

It’s been awhile but the old C-150 with 40deg of flaps benefited from the timely reduction in flaps after power was applied while holding significant control pressure.

When doing instrument approaches in my RV10, I keep the flaps in climb configuration until the landing is assured. That way the simple application of power with no trim changes is acceptable during a miss or go-around. That’s a good thing when in the soup.


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Jim K said:
Is this particular to v-tails? Other makes & models?
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Very similar in an RV-10. The 10, especially when light like when solo, is nose heavy and very close to the forward CG (I always fly with ballast in the baggage compartment when solo). As a result, it uses a significant amount of nose up trim when landing. Uncorrected on a go-around or touch and go and the application of full throttle will have you pushing very hard forward on the stick which could bite an inexperienced pilot with an abrupt pitch up and possible classic departure stall.
 
Jim K said:
Reading the beechtalk thread on the KSLE Bonanza fatal a few days ago... several posters mention that a large trim change is required during transition from landing to go-around. They were saying that going full power without re-trimming will produce a large pitch up and stall.

This seems foreign to me; all my time is in Cherokees, which will pretty much fly a set speed for a set trim position regardless of power. Cram the power in at Vref and it turns into a Vx climb.

Is this particular to v-tails? Other makes & models?
Click to expand...

Obviously will vary by type, but what you state is roughly right, and wrong. Yes in theory you trim for an airspeed, and the trim will do its best to stay neutral at that airspeed. But as you progress into higher powered aircraft, consider where the thrust from the propeller goes, namely over the tail. In a 140-160hp Cherokee, that thrust on the tail is somewhat insignificant. In a 250-300 hp aircraft, the change in thrust can cause a much more drastic pitch change. You get into aircraft like a 850 hp TBM, even more so. Also as you get into bigger, heavier, faster aircraft, the pitch forces get greater. In a Cherokee, the average pilot can overcome even the worst case pitch trim forces by hand. In some of the large twins I've flown, you need both hands and then some to overcome the pitch forces. Its not uncommon to almost fly those aircraft with the trim is some situations.

Then jump into something with a T-Tail, and experience entirely different pitch/power reactions.
 
midwestpa24 said:
In a 250-300 hp aircraft, the change in thrust can cause a much more drastic pitch change
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Which is why I was confused...My "daily driver" is a 300HP Lance, and it flies just exactly like the Archer I trained in with regard to trimming for speed. Go-arounds are a non-event, just takes more right rudder. I don't know how Piper did such a good job making the trim work at all power settings...maybe it's inherent to the stabilator design? Or maybe it's just that the -32 is a super-sized trainer design.
 
Bill said:
A better go around strategy (when there is room) with the Mooney is to add enough throttle to arrest descent, fly level while you get the trim and flaps back to takeoff position, then throttle up and climb out.
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That's exactly how I teach it in a 182. I don't think it's a huge deal but judging from the number of pilots I see treating the throttle like an on/off switch it could get someone into trouble.
 
dmspilot said:
That's exactly how I teach it in a 182. I don't think it's a huge deal but judging from the number of pilots I see treating the throttle like an on/off switch it could get someone into trouble.
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And not to derail, but in IMC and on an approach (practice), I found going missed that if I put in enough power to climb 500-700 fpm that I was more able to manage everything else. Cramming full power gives me an unnecessary 1500 fpm climb that can be both distracting, disorienting (spatial), and just another thing that might be happening faster to get me behind the airplane as I’m reconfiguring (I should never get behind, but stuff happens and risk reduction/management is the right answer).
 
I land in my little experimental with full nose up trim and (usually) full flaps. When adding power for a go around it takes a good push on the stick to keep the nose down until the trim is reset. I know this from practice and actual go arounds that I have done.

I know most of the superior pilots here never do go arounds ... but for us low rate guys ... ;)
 
Jim K said:
Which is why I was confused...My "daily driver" is a 300HP Lance, and it flies just exactly like the Archer I trained in with regard to trimming for speed. Go-arounds are a non-event, just takes more right rudder. I don't know how Piper did such a good job making the trim work at all power settings...maybe it's inherent to the stabilator design? Or maybe it's just that the -32 is a super-sized trainer design.
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And its largely dependent on the aircraft and design. A lot variables that affect handling. Fly enough different makes and models and you begin to see it.
 
Lightly loaded 180s and 185s an be a handful in the abort. 185 especially, of course. It's one reason I was always fussy about the Cessna seat rail/locks AD. I made sure that the rails and locks were good, then checked the seat structure itself for cracks or other damage that might result in a seat back failure in such a situation. Pushing hard on the wheel means pushing back hard on the seat back, and it had better be up to taking the strain. I have found many defects that compromise that, especially the clevis pins in the fully-adjustable seats. I have found those worn more than halfway through, ready to snap.

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NealRomeoGolf said:
Pipers are the best
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they are! But the Aztec loves to do a severe nose up pitch, nearly two handed yoke grabber, if you're not hitting the trim down in unison with the flaps. Caught me off guard when I was moving over it.. the CFI goes "oh yeah, sorry about that. Hit the nose down trim when you get the flaps"
 
Our club 182 will be a handful on the go without being mindful of trim. Problem is that you need a lot do nose up trim to land without severely fighting the yoke.
I’m even trimming over the numbers. So on the go with full power and flaps out things get real slow real fast.part of my mental checklist after jamming the power is to start trimming and yoke forward still I get those flaps up.
 
I fly a F35 Bonanza and Cessna195...you anticipate the control forces required to do a go-around...Rule 1 is to Fly the Plane...don't let the plane fly you.

Yes..considerable forward yoke pressure is normal on a go-around.

No electric trim in either plane...
 
Maybe I don't trim enough. I dunno. How was my landing on Saturday Jim?
 
Tantalum said:
they are! But the Aztec loves to do a severe nose up pitch, nearly two handed yoke grabber, if you're not hitting the trim down in unison with the flaps. Caught me off guard when I was moving over it.. the CFI goes "oh yeah, sorry about that. Hit the nose down trim when you get the flaps"
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I think Jim nailed it with the stabilator. Aztec doesn't have it. 28's, 32's, and 34's do. Does a Cardinal have a stabilator? I go from my Cherokee 180 and my dad's 300 Cherokee Six and the only difference is how much of a workout the right leg gets.
 
Electric trim is a necessary option in the C-182RG. Trimming constantly during landing and go-around with your thumb sure beats manual trimming.

I don't remember the 185 being a big deal.
 
The S-3 Viking had a pitch up severe enough to warrant an auto nose down trim with a certain forward stick deflection for certification.

Underslung engines were the root cause of that problem.
 
Racerx said:
I think Jim nailed it with the stabilator. Aztec doesn't have it. 28's, 32's, and 34's do. Does a Cardinal have a stabilator? I go from my Cherokee 180 and my dad's 300 Cherokee Six and the only difference is how much of a workout the right leg gets.
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Aztec has a stabilator. At least the later models I flew did.
 
Tools said:
The S-3 Viking had a pitch up severe enough to warrant an auto nose down trim with a certain forward stick deflection for certification.

Underslung engines were the root cause of that problem.
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Sounds similar to the now infamous MCAS system on the 737 Max series.
 
Can't comment on the others, but the approach to landing trim setting is pretty identical to the takeoff trim setting in the Navion (just about prefectly in trail with the elevator.).
 
flyingron said:
Can't comment on the others, but the approach to landing trim setting is pretty identical to the takeoff trim setting in the Navion (just about prefectly in trail with the elevator.).
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Same for the PA32
 
Racerx said:
Aztec doesn't have it
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midwestpa24 said:
Aztec has a stabilator
Click to expand...

Piper did a lot of variations with the tail design on the Aztec

The C model I'm flying in the club has a stabilator, it's a huge beast actually, allegedly Piper used the same design from the Comanche. According to what you'll read (yes, I went down a rabbit hole when I started flying the AzTruck) there were a few different stabilator designs in an effort to kill that bad pitch up habit, including an automatic trim interconnect on some F models. Ultimately Piper stayed with the original design as the others either resulted in slower cruise speeds or had other quirks
 
I once forgot to readjust the trim and flaps of my Mooney for a takeoff after a bit of an involved landing. At the time I was new to the Johnson bar and mine was (unbeknownst to me) in need of some lubrication. I took off, swing the bar and got it secured to the floor. When I looked up I was 3 mph north of a departure stall.
 
Tantalum said:
The C model I'm flying in the club has a stabilator, it's a huge beast actually, allegedly Piper used the same design from the Comanche.
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That was what I was always told, that the stabilator on the Comanche 400 came from the Aztec. I've only ever seen one, but it did seem bigger and beefier than the standard Comanche stabilator.
 
There's nothing worse than an unlubricated Johnson bar
 
NealRomeoGolf said:
Maybe I don't trim enough. I dunno. How was my landing on Saturday Jim?
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Like a butterfly with sore feet. I've made landings that good......but never when anyone was around to witness it.

I was particularly curious about the Cardinal. Does anyone here have one currently?

On all the Cherokees, Vref is almost always exactly Vx. I always thought that was just the way the physics of airplanes worked, but now I see they are often as much as 10 knots apart on some planes. I wonder if Piper did that on purpose or it was just a happy accident.
 
I find my 206 requires constant trimming during landing. On the go around you better be ready to hold it down if you go full power while jumping on the electric trim buttons right away.
 
Jim K said:
Like a butterfly with sore feet. I've made landings that good......but never when anyone was around to witness it.

I was particularly curious about the Cardinal. Does anyone here have one currently?

On all the Cherokees, Vref is almost always exactly Vx. I always thought that was just the way the physics of airplanes worked, but now I see they are often as much as 10 knots apart on some planes. I wonder if Piper did that on purpose or it was just a happy accident.
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I used to own a Cardinal. Have few hundred hours in them. Haven't been following the thread closely. What led up to this question? Watcha wanna know?
 
Reading the POH on basic trainers, I saw that the trim should be adjusted so that the plane rotates with barely any touch. I guess I didn’t adjust the trim correctly as I need to pull back a bit to find the sweet spot (sometimes I try to put the plane in ground effect but I usually wait to rotate until climb speed and it’s ready to go), I also like to fly the airplane and it is easy to do with the hands, adjust while in cruise. Maybe a newbie pilot thingy that I need to perfect with experience.
 
Tantalum said:
There's nothing worse than an unlubricated Johnson bar
Click to expand...

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luvflyin said:
I used to own a Cardinal. Have few hundred hours in them. Haven't been following the thread closely. What led up to this question? Watcha wanna know?
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Does the cardinal need significant trim adjustments on a go-around after firewalling the throttle?
 
Some blast in the cargo area moves the CG and reduces this issue in every plane I have flown.
 
Jim K said:
Does the cardinal need significant trim adjustments on a go-around after firewalling the throttle?
Click to expand...
No. Couple swipes of the trim wheel. Even if you don't do it, it doesn't take all that much pressure to keep things from getting out of hand.
 
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Jim K said:
...
...Is this particular to v-tails? Other makes & models?
Click to expand...

It's a thing on my A36 ( a straight tail Bonanza) too. It isn't something that can't be handled though. Like mentioned above - you just push and adjust the trim after adding throttle. It's definitely not a reason to avoid flying a Bonanza.
 
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