I find that I trim back to almost full nose up on my best landings. My Mirage training taught a method of trimming back on landing. Does anyone else find that this is a great way to make smooth landings?
Sounds like a hand full if you have to go arround for the deer on the runnway. I am trimed at the same place as" take off", and the go arround performance is as good as it gets.
I don’t like it.
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I like my students to be able to feel the back pressure required for the proper landing attitude. Trimming defeats that.
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It’s one more thing to be futzing with when one should be concentrating on the landing itself.
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As mentioned, it could put the plane out of trim on a go-around, again giving one more thing to futz with right when things tend to get busy.
I remember on a Cessna 210 with a forward CG I would use the trim prior to the flare to help just a bit. But that had a heavy pull on the flare that the Cirrus doesn’t have.
So, again, I’d say no, But That’s Just Me™!
I agree with the other two posts. The trim is not giving you any more up elevator. It is just reducing the pressure on the control stick. I have never found the control stick pressure significant on landing.
You are not getting any benefit from using the trim.
You are getting a significant detriment. If you need to go around for any reason, you will have an out of trim airplane to deal with. As soon as you bring up the power lever that out of trim elevator is going to be way more effective and result in a very significant nose up attitude just when you are trying to deal with the go around.
None of this indicates that you should not continue to apply additional nose up elevator during the landing sequence. My best landings are those where the “ready to land” stall horn goes off very close to the runway and I continue to apply enough up elevator to hold a constant pitch attitude with a small but constant nose up attitude. If there is increasing up elevator being applied as the airspeed bleeds off you will occasionally be rewarded with a landing that is not even a “chirp” but is just the commencement of a vibration from the tires rolling on the runway.
I just can’t see how the trim motor is going to assist in this venture. The trim motor has two drawbacks in this application: (1) it is too constant and (2) it is too slow. It is like trying to finesse a put with a sledge hammer.
When I first started flying the SR22 back in 2002 my landings were not nearly as good. I would set up the approach o.k. and then when I got near the runway I would hesitate to change anything.This is not the right technique. You need to keep working the elevator all the way down. My instructor even advises an up elevator during taxi to minimize the load on the nose gear.
I have not found the need to bring the elevator all the way to the stop generally. I did fly the turbo and I found that I had the elevator all the way to the stop. We had two in the front seats and one lighter passenger in the rear and no luggage. I think the weight of the turbo required more up elevator on landing.
I don’t know anybody that teaches the use of trim on landing. Where did you pick that up?
Stanley:
Any reason you posted this on the Guest forum? You will probably get more responses if you posted this on the Member side.
You’re right, in the case of planes like the Cirrus where trim is by bungees or equivalent.
But with a conventional trim tab, the trim actually gives you LESS authority.
Since the trim tab moves opposite to the desired effect (moves DOWN to help you hold the elevator UP, and vice-versa) you could theoretically get more elevator authority by trimming for additional pressure.
Try trimming for 100 knots on the ILS with 1/2 flap. Do NOT trim again. Continue adding light back pressure as you slow and decrease the power. Fly it on 3-5 knots above stall speed with only 1/2 flap. You can’t even hear the speak of the tires.
GREAT TECHNIQUE, Stan! Always keep the aircraft trimmed for the current condition. These naysayers are not getting the big picture. The “what if you need to go around, you might crash” argument holds no water. If these arm chair quarterbacks ever went out to test their theory, they would find out that the SR22 takes off beautifully with FULL AFT TRIM. As speed approaches the appropriate lift off speed, the nosewheel will come off the ground with almost no effort at all. After the mains lift off, simply start trimming nose down so that the aircraft maintains a pitch attitude that will allow it to accelerate to the 100 to 120 knots that the airplane likes to climb at.
Ironically, the phobia that drives this paranoid view that “excessive up trim” can cause a stall/spin/crash scenario, and the resulting reluctance of instructors to insist that the pilot keep the aircraft continuously in trim may be causing the very problem they are trying to prevent. I have found that most pilots I fly with are very uneasy giving the stick/yoke a healthy push, even when sorely needed to prevent a bad situation from getting rapidly worse. Case in point: engine failure at less than 200 feet AGL during a Vx, or even a Vy climb. Another is the unexpected (to a pilot who always takes off with the airplane trimmed to somewhere near Vy) pitch up that will occur when an aircraft is lifted off with the elevator trim inadvertently positioned to near full aft such as sometimes happens during a touch and go, or if the elevator trim position is not carefully checked prior to take off.
Let’s look at the “deer on the runway” scenario. What I advocate is that as you begin the flare, you continue to trim the nose up so you are using just the slightest pressure to finesse the AOA to just where you want it. Suddenly right in the middle of the flare, a deer runs out into your path. If there is no room to maneuver, you are much better off doing nothing except continuing to reduce power and raise the nose. If you hit the animal, at least you will minimize the energy of the collision and at the same time reduce the possibility that large parts of this unfortunate creature will end up coming through the windscreen. If on the other hand, the hypothetical deer is far enough down the runway that you can be assured to accelerate and climb over it safely, you simply do just that. Add power and as the aircraft is already trimmed to the current airspeed, it will just start climbing at that airspeed. Perhaps this speed is only 65 or 70 knots. That’s fine, as you gain the first 10 feet of altitude, you can lower the nose a bit, using the trim to keep the forces light and repeat as necessary until you reach the desired climb speed.
Another thing that is being overlooked by the “never trim into the flare” crowd is that it is physiologically much easier to accurately control the aircraft when stick forces are light. Think about this analogy: would a surgeon like using a scalpel connected to a spring attached to the edge of the operating table. Of course not. There is simply never any reason to fly an aircraft grossly out of trim for the current flight conditions. In the Cirrus, the situation is made even worse as what is fighting you on the controls is not even a “real” trim tab but just a spring cartridge: a soulless mechanism that has stiction, slop, and non-linear feel reminescent of the similar one that slammed the screen door behind us in the days of our childhood.
But the ABSOLUTELY WORST THING about not trimming in the flare is that it begets one of the single most dangerous habits I must continually correct during flight reviews: the tendency of many pilots to reduce airspeed as the ground approaches without being aware of it. After getting in the habit of not trimming in the flare, the pilot invariably extends this not trimming the airplane further and further out on final as his proficiency degrades. This is caused by many things: overconfidence, distraction, nervousness about the final phase of the landing, poor scan due to fixation outside the aircraft as the ground approaches, etc. However, the end result is the same: often during landings, BUT IN VIRTUALLY EVERY SINGLE CASE DURING ENGINE OUT, GLIDING EMERGENCY LANDING PRACTICE, the pilot will invariably begin to subconsciously pull back on the yoke/stick as the ground approaches, giving up airspeed, stall margin, glide distance, and reserve AOA needed for a proper flare.
I realize that many instructors will not continue to simulate engine failure below 500 to 1000 feet. That is their perogative, and I respect their right to train using whatever guidelines they see fit. That said, I won’t sign off a flight review with any pilot who cannot demonstrate good consistent airpeed control while gliding down to less than 100 feet from the ground. Naturally, I do this in a few selected areas that I am intimately familiar with and that I recon before this part of the flight. What I usually see is that most pilots can do a decent job of maintaining their chosen glide speed down to at least pattern altitude, but as the aircraft continues to descend, they begin to lose their religion as the ground comes “rushing” up. Unfortunately this results in seriously courting a stall just as altitude become insufficient for a recovery, especially where no power is available to assist in getting the wing flying again.
The bottom line is that controlling AOA is vitally important to safe flight. For light aircraft at load factors near one, airspeed is the most reasonable proxy for AOA. Airspeed is best controlled by combining good scan technique with proper trim technique. For all practical purposes trim controls the airspeed the aircraft wants to fly at. If you keep the aircraft trimmed for the desired speed and fly with a light touch, it will stay at that speed, even if you become momentarily distracted. Therefore during an emergency, when you will certainly be distracted, you are much better served if you have strongly ingrained the habit of flying the aircraft with a light touch AND CONTINUOUSLY IN TRIM!.
So congratulate youself on your good consistent landings, but more so on learning a technique for controlling AOA that may save you life some day.
Vaughn,
Great, thoughtful post. But one question about the bit quoted above; I haven’t played with it extensively, but I imagine that prop blast over the elevator may affect what trim speed a particular trim setting holds. I could see that you might be trimmed for 80kts with 12"MP, but when you suddenly add full power the elevator could become more effective and the trim speed would be lower. But now I’m going to have to go out (at altitude!) and play with this.
YIKES!
That’s pretty strong language!
I can only speak for myself, but my advice comes from my experience instructing, backed up by my own experience.
While not a “trim Nazi”, more than a few problems in flying can be traced back to improper trim technique. CFII’s (which we both have in common) often see that when starting a student on their instrument training.
But learning to land an airplane is difficult for some students, and can become problematical for some experienced pilots as well.
My experience is that the more factors you remove from the landing sequence, the easier it is to concentrate on the “right” things.
Therefore, I try to get my students into a position where, at about 50’ to 100’, they have the airplane configured for the landing, and ONLY have to concentrate on the roundout and flare.
For me, that precludes last minute changes in power (which should normally be at idle), flap setting (which should normally be full flaps) or trim (which should be correct for the final glide)*.
But any given pilot may come up with his own techniques that work for him, and that’s fine.
I don’t know many instructors who would teach a student to still be trimming throughout the roundout and flare. I don’t know many Cirrus pilots who do that.
But again, That’s Just Me™, and whatever works for you and your students, have at it!
And I’ll try to work on both my phobias and my paranoia!
*I’m discussing small airplanes here, and my advice may not apply to larger planes and/or jets, where I have no experience.
I am in Vaughn’s camp on this one. I always had trouble holding off the nose when trimmed for my descent on final. My landings were mostly sort of a boom boom- mains and then nose wheel right after.About 4 years into my Cirrus ownership I read someone’s post where he said you don’t want to hold the entire weight of the nosewheel in your hand in the flare and advocated trimming that out in the flare. Wow did that make a difference. Now I feel I can easily do whatever I want with the nosewheel-and it’s no problem making the small adjustment in the flare-especially because it’s purposeful and effective.
I know you can hold off the nosewheel without re-trimming because I’ve done it. But I found this method is more effective.
Good question. Prop blast over the elevator does indeed have an effect, which depends on a number of things. Most piston powered aircraft that have power to weight ratios approaching 10 lbs/hp need significant thrust offset built into the engine mount. The TBM, for example, has 3 degrees of right and 2 degrees of down thrust. (Apologies for not having the Cirrus numbers. Perhaps someone here knows them). The T28 is probably the most interesting example with regards to thrust offset. When the T28 was built, the idea was to create an inexpensive jet trainer so considerable right (and down) thrust was added; a feature that is very obvious even looking at one on the ramp. This canted thrust reacts so effectively with the vertical stabilizer that right rudder is not necessary on takeoff (just like with a jet). Another design consideration that affects the interaction of power and trim is the incidence of the horizontal stabilizer, or more completely, the relative incidence of the horizontal stab and the wing, relative to the thrust line, and the camber (including the selected flap configuration) of the wing and stab/elevator. A detailed explanation would probably bore most so I won’t go there, but it’s obvious by drawing a simple diagram that if the prop blows down (as opposed to straight back) over the horizontal stab, increased propwash will tend to raise the nose. In addition, as you point out, the same applies to the elevator so yes, when the elevator is up, increased propwash will pitch the nose up. CG also affects the (stick free) change of airspeed with power. A forward GC destabilizes the airspeed (stick free airspeed will decrease with increased power, just as you intuited above) with respect to power in two ways: by increasing the lever (from the aerodynamic center to the horizontal stab/elevator) and because down force on the tail will increase due to increased airflow.
Remember that the amount of air going over the horizontal stab/elevator depends on airspeed as well as propwash. The propwash effect would be less going from 12" to FT in a 170 KIAS descent, and greater in an 80 knot climb. Because of this, it’s not possible to build an aircraft that is perfectly “honest” at all airspeeds/power settings, but a good design comes close. You may remember me offending some Cirrus owners in the past by stating that the Cirrus is not a great handling aircraft. My comments were not meant as an insult. Every aircraft is a compromise. Cirrus has focused on efficiency, comfort, and good looks and has hit the mark on all three. Yet for all of it’s handing faults, the Cirrus does well in this area also, in part due to a phenomenon called blowback. As you know the Cirrus elevator “trim” does not use a conventional trim tab, but just a spring that “tends” to hold the elevator where it was trimmed. I say “tends” because the spring stretches, so when you apply more power, the increased propwash actually reduces the up elevator (unless the pilot holds the stick in a fixed positon.) The net effect of this and the other design elements of the Cirrus make it quite safe in this respect. No, an SR22 will not hold airpseed accurately in all airspeed/trim/flap configurations, yet, you will find it comes close enough. Can you find a GG, flap and trim configuration that will cause the aircraft to stall simply by increasing power? I don’t know off hand, but that’s not my point. There is no trim position that is ideal for all airspeed/power combinations. That’s why they put the switch right on top of the stick: to make it easy to trim simultaneously while doing other things. (now if they would just move it another inch or so, so you wouldn’t need a double jointed thumb to use it as intended!)
I still stand by my position: The safest, most professional way to fly any aircraft is to keep it always in trim. Yes, that means you must be constantly trimming while the airspeed, configuration, and/or power are changing. But as you become more proficient in this technique, you will find it no more workload fighting the springs to accomplish the same thing without trimming.
Thanks for all of your efforts on behalf of COPA and your thoughtful response. I will look forward to reading about any data you come up with. Also, I suppose, since you have been so helpful and courteous, I will have to reciprocate and at least sign up again. I really don’t begrudge COPA the yearly dues. I’m just still so frustrated over this “no threaded view” issue. I sure hope it’s still something you are looking at. I’ll be flying until the middle of the week, but when I get back, I’ll figure out how to pay my dues…see you on the “other side”. Vaughn
Sorry, Ed. You are such a nice guy and I really got wound up and used what I see in retrospect to be insulting language. Thanks for all of your thoughtful contributions to the site and for treating my so kindly on this one. You are quite right that I was out of line and were a real prince in the way you it. Please accept my sincere apology. I think we may have to agree to disagree on the crux of this trim issue, but that’s fine with me. I always enjoy reading your posts, respect your position and am certain you have contributed immeasurably to the safety of the Cirrus fleet.
Stan,
I do the same. I apply trim as I begin to flare. I don’t have the trim against the stops. I trim it out to take most of the pressure off the stick, as I do in all the other phases of flight.
Most of the time my landings are very good. I have found that this gives me the most consistently good landings. During my last annual training my CSIP stated that I land the Cirrus better than any of her other students.
I practice go arounds, T&G’s, etc. and have not found it to be an issue.
Tony
tony
I recently had my annual done on my 2007 SR22 GTS , of course the bill was a suprise as usual. I thought the GTS in 2007 came with a 3 warranty as part of the package which would have covered about $ 2,500 of my bill but repair shop said I was not covered. As I did not save the 2007 price list (really dumb), I was wondering if anyone had thoughts on this subject. The paper work that came with my plane has the 3 year entended warranty paper work in it but maybe that was put there in error. I would appreciate any comments one way or the other. Thanks
In the SR22 I trim for my target final speed–as low as 70, as high as 77 depending on weight–on short final, then flare manually. I like the ability to “feel” the plane and the force required to get that full aft yoke, minimum airspeed touchdown (I’m a happy parishoner of the Church of Benson in this respect [:D]). On a go around some nose-down trim is in order but it’s not excessive and I don’t find it a distraction.
In my Katmai I use full aft trim on short final, this gives 55-57 KIAS depending on weight, CG position, and power setting. I further adjust speed manually to as low as 40-45 KIAS over the fence for a maximum effort short field landing with 13-14" mp. A full power go-around gives a marked nose-up attitude that is relieved by 12-13 “flicks” of the trim wheel; more work than in the SR22 for sure but not burdensome if you’ve practiced occasionally. It also helps that, if you’re even close to coordinated flight the Peterson 182 is quite difficult to stall power on.
And your post has what to due with the topic at hand? It almost looks like a Troll post! What is your point…Ed
I agree with everyone else, screwing around with the trim is a waste of time, difficult, and pointless… With AP off, and full flaps, (crosswinds not consideres,) you should be able to land with minimum of effort
Fred
I agree. Don’t screw around. Just dive at the runway, and pull up before you hit. That works for me.
The important part is to “pull up before you hit”, they never put that in the POH…but i think its important
When i was just starting I did one of those bouncy landings, the wheels hit the ground several times, some guy happened to be on the unicom, calling in But when i heard his call sign numbers, I had to ask … " Who’s counting" ?