Thanks guys, I've decided to keep trimming on final.

However, what about on takeoff and climbout? This is the part I find quite difficult, as the forces are quite considerable on the 180hp 172. My instructor always told me to be on the throttle till circuit height, then A-P-T, turn downwind etc.

Use trim. If the trim isn't correct then correct it. After take off OR final.

It should be a semi-automatic response...

I believe, if memory serves me correctly, that you have the luxury of a throttle friction nut on the 172, so what's the problem with one second off the throttle and on the trim wheel? The aircraft is not going to fall out of the sky.

QDM

G-Spot

Could you explain more?

e.g. Power & Pitch = Performance ...the golden rule of attutude flying.

Trim an aircraft to an airspeed without considering pitch/power and surely you do not necessarily get the required performance ... just accurate speed control.

e.g. trim to approach speed with too little power and you get excessive sink - you land in the undershoot unless you correct.

Therefore shouldn't we set the attitude (picture), set the power to give us the airspeed and sink rate required to maintain the glidepath and then trim to remove the control forces so that the aircraft is stabilised?

Hi,

Regarding trimming... the aircraft should be in a trimmed state for all phases of flight... and by that I will simplify it to Climb, Cruise, Descent, Approach. No trimming in turns.

I dont teach my students to trim before 300ft QFE on the climbout unless the the aircraft is a long way out of trim. Then.. hand back on the throttle until at circuit height.

Trimming on approach is a must... its hard to land well without a stable approach.. if you havent got the speed stabilised and approach stabilised with the aircraft in trim by 300ft then go around and try again.

Loony - always wondered why the hand on the throttle? I was also taught this and always do it - the reason I was given was so that "when the CFI does an EFATO on you you will notice when he grabs the throttle!" but I suppose there's another reason!?

Cerpently

You are flying downwind in the circuit, aeroplane perfectly trimmed for straight and level say 95knts/2350rpm in a warrior, assuming there is nothing below you lower the nose to increase speed to 110 knts then reset the attitude.

Nose climbs due to increased dynamic pressue on the trim tab, now with this new found increase in altitude raise the nose to say 65knts and reset the attitude to S & L. Nose drops away as you would now expect.

Classic mistake or (back to the thread) "BadHabit" is student or novice PPl'er who from crosswind in the circuit lowers the nose at circuit height, doesn't give the airplane a chance to accelerate properly and trims for straight and level at 80knts - turns downwind and due to the aircraft accelerating in the turn increases altitude to cct hght +100

Had the privilige of checking out a retd. grp commander in the RAF who's last job was flying F3's. You'd think it would be very straightforward to sort out a PPl for somebody with such experience but he would happily admit it was actually reasonably difficult.

How did he get through it

Old RAF adage at every phase of flight "TRIM, TRIM, TRIM"

If its good enough for the RAF doing 7 miles a minute its good enough for us spam can drivers doing 1.5!

And to answer the second part of the question, on approach the speed is maintained by the elevator and the trim tab. Think of the throttle as a rate of descent/climb leve. It either gives 0fpm rate of climb/descent or a positive or negative figure. Large throttle movements will give a variation in airspeed, subtle changes in power wil not, they only modify the rate of descent sufficiently to remain on your intended glide path to the runway. This is assuming of course that you are at the right height turning finals.

I always advocate getting into the "letterbox" which is an imaginary slot at approximately 1.5 miles out at approximately 550-600 feet.

If you get into the letterbox and set the power that your instructor told you to set the first time you flew the aircraft in the circuit when you were getting checked out, then the subtle changes in power on an average day (wx wise) are tantamount to the instructor figure plus/minus 250 rpm.

This will give the the dearly sought after stable approach you can clearly see that the good approach comes from a good base leg - getting you into the letterbox....

"Lazy rudder syndrome"
 

Here's a link that may assist with another bad habit that most of us tend to develop over time:
http://www.avweb.com/articles/profil...azyrudder.html

G-Spots

I understand where you are coming from now, but for some of us the stick controls rate of descent and power the airspeed.

In this scenario, the two factors are adjusted to give the required performance and then the trim is used to take the weight off the elevator.

When you think about it, the actions and results are the same, but the conceptualisation is different.

Just noticed this thread and find the subject matter interesting. Certainly some of the answers are interesting.

But what is more interesting than all the above, is that it is fundamental to ensure that your aircraft is in trim - in ANY phase of it's flight.

But for landing it must be correctly trimmed, and I would always expect to have it 'finalised' by 200' or thereabouts. But........it is still possible that further trim might be required down to around 100'. Trim cannot, however, be ignored. It must be adjusted, and there NO rules to say that it should not be adjusted at ANY time.

The elevator controls the angle of attack of the wing. All else stems from that and all roads lead back to angle of attack.

;)

QDM

QDMx3

All I am saying is that Power & Pitch = Performance. Pretty standard stuff really - basic attitude flying technique.

The the airline constituency uses the stick to control sink and power to control speed. Thus you adjust an input and monitor the relevant indicator. (you will also understand that P&P=P also allows the stick to be used for speed and power for sink.)

BTW, the US Navy uses the same technique.

Finals three greens

What are you flying? It sounds probably like you are flying an aircraft with a reasonably broad speed range.

In this case then yes I would agree with your theory and of course if it works for you then fine. Exercising my diploma in diplomacy if you are flying a "normal" single i.e. 2/4 seats fixed pitch prop etc then I think that your technique would go against current and historical instructional technique.

Having said that I would reiterate if it works for you then fine..

Also I'd be interested to know if you fly IMC because I think you would have trouble flying a stable ILS with your technique.

I havn't thought that through completely but it just sprung to mind :rolleyes:

PS RAF have a technique called point and power anybody care to explain?

IFRet Indeed a healthy topic!

Bad habits
 

How about long flat drag it in type approaches for being NBG ?
OK for counting hedgehogs but not good for much else.

Landing with carb heat in HOT is very good for killing off the go-around option should it arise (it will, and when you least expect it)
How many pilots have three hands ??!!

TTH