Effects of Power

[Guest pelorus32]

This came up in another thread. Merv and Tony, amongst others, made the point that every student learns about this from the first lesson.

 

In my view this is the most confused area of flight training. In particular it is extremely poorly taught with respect to managing the approach. I've witnessed a number of attempts by instructors to separate out the effects of power and elevators when trying to help a hapless student understand why they are having trouble managing airspeed and sink in the approach.

 

Wolfgang Langeweische covers this area very well in his book - written around 60 years ago. Let's see how well we can do.

 

So over to Tony, Nev and others. Let's have a clear statement of the effects here. You'll help many a hapless student.

 

Regards

 

Mike

 

 

[motzartmerv]

Ok, i'll have a stab.. It isn't an easy concept to put into words, but i'll try..

 

To understand it propperly we need to look at two aspects of flight. They are called the region of normal command and the region of reverse command.

 

The region of normal command deals with the acft flying at or above the minnimum power speed (speed for max endurance).

 

Above this speed most light acft have strong speed stability. Think about an acft in steady, straight and level flight at a speed higher then min power and a corresponding power setting. If the acft is disturbed by wind or wateva to a higher speed, there will be a deficiancy between the engine power set and the power required at the higher speed..Now, if the disturbance reduces the speed, there would be a surplus of engine power set compared to the power required at the lower speed..

 

So, the tendancy is for the acft to return to the orriginal speed without command inputs from the pilot. Also in this speed region logitudinal stability is quite strong with a heavy corrective force exerted on the tailplane which tends to return the acft to its original attitude. A decrease in angle of attack increases speed which commands a higher power setting..

 

Now the tricky bit,

 

At speeds below min power speed (like during approach) a disturbance that causes an increase in speed will cause a surplus of power and vice versa.. Its a reverse of whats happening at the higher speeds..

 

So at apporach power settings we really need to control speed with angle of attack and control altitude with power..

 

In the region of reverse command, if speed is increased by decreasing angle of attack, then unless engine power is reduced the acft will climb (due to the surplus of engine power at the higher speed). If the speed is reduced, then unless engine power in increased the acft will descend (due to the deficiency of engine power.)

 

So what ends up happening is pilots tend to chase the VSI around the dial by altering angle of attack and juggling power..

 

Then of course theres the slipstream effect when adding and reducing power which causes the acft to yaw left or right depending on wether your adding or reducing power. These effects are quite different on different types. I won't go to far into it but serfice to say that airflow wrapping around the fuselage and whacking the tail surfaces on one side provides a turning effect about the normal axis..

 

Now what does this all mean to us as pilots trying to get a nice smooth approach down the keys??

 

Well, this is where im sure im gunna get bagged, but here goes..

 

In the jab i teach to just keep the nose pointed at the threshold and don't change the angle of attack unless the aspect of the runway changes.. If the turn onto final has been done at the right height and distance out then things should fall into place..Point the nose at the threashold and control "speed" with power..

 

But thats the opposite to what you just talked about andy what the hell are you on about???

 

Well, it all rely's on getting the approach right and that starts well before the turn onto final.. It requires good judgment for the power chop, flap deployment and turning points.. But flying the numbers is the key here.. allowing for wind, reduce power approaching 45 deg from the threshold and make the turn onto base, steady the speed and deploy flap.. You should be looking to turn final at around 600-650 feet agl and rolling out at 500.. If to high get the second stage of flap out but maintain speed. If to low delay the flap untill the correct glide angle is achieved, meanwhile keeping the nose pointed at the threshold and speed controlled with power..

 

I don't know why, but in the jab it seems to work much better then having the guy in two minds about speed with attitude and height with power..Its sort of a self correcting way to do it, because if the guy keeps the nose pointed at the threshold and he's low, he will be slowly raising the nose which will reduce the speed, so a power change is needed, so he has a higher nose attitude and more power which reduces the sink rate and gets him back on track, conversly if he's to high then he keeps the nose down (pointed at the threshold) and this increases speed which he respods to by reducing power..So in effect he is controlling height with power but doesn't need to keep juggling attitude and power...

 

Im sure not evryone does it that way, but it works for me..

 

Ok, im ready for the balls of fire now..

 

cheers

 

 

[Yenn]

motzartmerv. I think you lost me with all that theory, but my technique is to fly the final leg by holding speed with attitude (elevator) and keeping the aim point constant with power, except that most of my landings are done with power off and the aim point is controlled with side slip. Don't start an argument about side slip and forward slip as that is irrelevant in my opinion.

 

The big thing to bear in mind is that getting the nose too high and speed too slow, needs lots of power to control and you may run out of power, in fact you should always be ready to run out of power at any time.

 

 

[motzartmerv]

Yenn.. sorry if i lost you with the theory..As i said, its dificult to verbalise without whiteboards and little model acft..hehe.

 

The technique i was talking about is practically the same as you described..Only the nose never leaves the threshold..The same problems apply when talking about being to low, theres only one way to correct and thats add power, and as you said power may not be there forever.. The way i do it keeps the picture the same, the threshold is always in the same place in the windscreen.. If they are way to flat then a go round is on the cards..

 

alot of RAA guys use full glide approaches anyway so the speed is controlled with attitude obviously and excess height is slipped off..Probably the safest approach as power isn't needed at all.. but my hands are tied at my school, they teach powered approaches, which if your high and useing my technique you end up in a glide anyway..

 

 

[Guest pelorus32]

OK I'm going to have a shot at this, I hope others will come in to add, correct and amplify.

 

The first thing I want to do is to deal with Angle of Attack - AOA. To repeat what has been said many times AOA is the angle which the chord line of the wing makes with the relative airflow.

 

Lift from the wing requires passage through the air at some AOA. In "high speed" flight the AOA is small and the speed is greater. In level flight lift = mass. If we slow the aircraft down but still wish to fly level then I need to increase the AOA - I need the same lift but more of it comes from AOA and less from speed.

 

I change the AOA of the aircraft with the AOA controller - the elevators. When I trim the aircraft I trim for a given AOA - the elevator trim is the AOA setting control.

 

Now I'm going to use an a/c which has the following characteristics:

 

• Cruise 105 knots
   
   
  
• Vfe 67 knots
   
   
  
• Approach 60 knots
   
   
  
• Approach power 3000 rpm
   
   
  
• ROD at approach power at 60 knots 500fpm
   
   
  

 

 

As I turn base I increase my AOA (apply back stick) and reduce power to idle. The speed comes back from 105 knots to 67 knots and I engage 15 degrees of flap; I open the throttle to 3000rpm and I set my speed to 60 knots using my AOA controller - the stick. Then I use the AOA setting control - the trim - to take the weight out of the stick. I trim back to set the new AOA as the balance situation for the a/c. The aircraft is now flying at a higher AOA than before the turn, at a slower speed and instead of flying level it's sinking at 500fpm. I can take my hands off the stick and the a/c will continue merrily at 60 knots going down at 500fpm.

 

Leaving my hands off the stick I decide to experiment: I open the throttle by 500 revs to 3500rpm. What does the aircraft do? It pitches nose up a little way. Why does it do that? Because it is trimmed for a particular AOA and by adding power I reduced the AOA so the a/c pitched nose up to return to its higher AOA - the AOA it was trimmed for.

 

I return to my 3000rpm 500fpm situation at 60 knots, then I take my hands off the stick and reduce power to 2500rpm. We know what the aircraft does - it pitches down to maintain its trimmed AOA.

 

Let's sort through a number of other parameters. When the power is increased and the nose pitches up (in the ideal a/c) the speed will remain the same but the aircraft will sink at a reduced rate and may even climb. When the power is reduced the a/c will stay at roughly the same speed but the sink rate will increase. We're learning how to make an approach.

 

That's in an ideal world. In the real world, in a real world a/c we have to compensate slightly. The a/c isn't perfect and it doesn't do precisely as it should. In reality we need to behave like there is a disused pair of panty hose (stay with me please) one end is tied to the stick and the other to the throttle and the middle bit is behind our neck.

 

When you open the throttle - push it forward - the panty hose will pull the stick back a little. When you close the throttle the stick can go forward a little. The movement is generally not one-to-one so the panty hose is a metaphor not an actuality (sorry guys).

 

So now we have turned final we are at our 60 knots/500fpm and the world is good. The aim point is glued right where we want it and we are sliding on rails.

 

But we start to sink. Now the first thing is how do we know we are starting to sink? Well the aspect changes (see below), the aim point slides up the screen and because we adjust the stick (increase AOA) to hold the nose at the same attitude the IAS falls.

 

This is where the confusion arises in my view. The tyro pilot thinks "airspeed falling - need more power". What's actually happening is that the sink is the primary issue and that's what is driving the chain to require more power. If you encounter sink you will either hold the nose up to stay on glideslope and therefore lose airspeed or you will add more power to deliver more lift to stay on glideslope whilst maintaining airspeed or you will allow the a/c to sink below glideslope whilst maintaining airspeed. The stick is used simply to maintain fine adjustment of AOA and as a secondary effect IAS.

 

This picture is not yet fully complete but I'm going to leave it there...except to finish one little detail.

 

When you are landing VFR there are only 3 things in your scan - all else is irrelevant: Aimpoint, Aspect, Airspeed - the three As. Notice that Attitude is NOT there - if the other three are right attitude is taking care of itself. Just to clarify - we all know what Airspeed is, the Aimpoint is the point that we have fixed in the one place on our screen and Aspect is the way the runway looks - if it looks long and level we are low and if it looks short and like a plan we are high.

 

For all the people who, like me, were taught Attitude flying this approach (!) might sound like sacrilege but it works. And what's more I think it explains the relationship between the effects of power and the effects of the elevator.

 

Please feel free to go for your lives on this. Particularly I think it's worth looking at situations where the airmass is perturbed and at other phases of flight where the effects of power are interesting. For simplicity I have left out discussion of changes in power settings on the need for rudder etc.

 

Regards

 

Mike

 

 

[motzartmerv]

Mike, i like the panty hose ennalagy.. I think we are on exactly the same page, by keeping the aim point fixed and the speed right all else should fall into place because its a self correcting mechanism.. When the acft gets a little low the nose needs to be raised to keep the threshold , so the IAS falls which the pilot responds to by adding power..

 

cheers

 

 

[Guest TOSGcentral]

Yeah OK Mike! I will put up this post as a basic chopping block that all can take a swipe at.

 

 

Warning! A lot of Heretical concepts (so I should be burnt at the stake – especially as I am a Pagan anyway), maybe a long post (cannot disappoint my fans), and perhaps a bit tongue in cheek (but spot where).

 

 

Before we get into engine effects on approach then let us ensure that we are all on the same page with what engine effects are and what the pilot may have in mind as part of an approach control consideration.

 

 

ENGINE EFFECTS #1. The engine makes you go up and down while the stick determines at what speed you do (or try to do) this.

 

 

ENGINE EFFECTS #2. Teaching of engine effects is normally crap, the reason for which resides in the instructor’s lack of attention when PMI was being taught/poor tutoring (tick one or both) and compounded by an inadequate flying training syllabus compelling the instructor to do it in the ordained way! This results in residual confusion or misinterpretation in the minds of students that causes future training challenges to unravel the misconceptions and omissions such that students do not waste money on repeating exercises where engine effects play a considerable part.

 

 

ENGINE EFFECTS #3. Apart from implanting the concept and reality that the engine does in fact make you go up and down (translated to the student at this stage as apply more/less throttle, no a bit more/less, thank you) the student should be very comfortable with aerodynamic energy control of the aircraft (attitude, turning, aileron drag etc) before being formally taught engine control. Having achieved this happy stage you can teach basic engine control as a superimposition on aerodynamic energy control and do so in a few minutes while achieving full understanding, no confusion, and establishing a worthwhile teaching platform for the future.

 

 

ENGINE EFFECTS #4. Time should be expended (not usually very much) in melding together the aerodynamic and engine energy control so that the student now has nearly full control of the machine – or at least sufficient to be taken on to the techniques parts of the syllabus.

 

 

ENGINE EFFECTS #5. What are generally regarded as ‘engine effects’ should now be taught at an appropriate time bearing in mind that one of them (slipstream effect) will have already been covered. These should be taught prior to commencing take off instruction and, while sort of valid for nosewheel aircraft, are essential foundation awareness for taildraggers in order to work out why the procedures required. There are four engine effects: Slipstream, Torque, Asymmetric Blade and gyroscopic precession. We will go through them in turn.

 

 

ENGINE EFFECTS #6. SLIPSTREAM. This is the spiralling airflow from the propeller (particularly in tractor engine layouts) that causes the air to strike mainly one side of the rear fuselage and fin/rudder causing yaw. The amount of yaw is dependent upon the amount of engine power applied and can result in either a numb foot to keep an out of trim aircraft straight, or a depressingly inhibited rate of climb from the yawed condition on take-off.

 

 

The situation is generally less of a consideration on approach as you are normally well throttled back but may become significant if you have to make a substantial power addition that will yaw the aircraft. In turn this will invoke the secondary effects of yaw which is roll – requiring opposite aileron to counter and could lead to crossed-controls, a change in drag and possibly impact on visual approach path direction judgement.

 

 

ENGINE EFFECTS #7. TORQUE. Normally only a consideration on take off, particularly on taildraggers but also applies to nosewheel types. This effect is the reactive force that persuades the aircraft to roll in the opposite direction to the rotation of the propeller. On the ground this causes one mainwheel to be depressed harder into the ground causing a braking effect on that side and a consequent swing off the intended line of travel.

 

 

For most of what we fly that is about the sum total of the hassle – but the effect is still there when flying, particularly if substantial and rapid power inputs are made. This does not normally impact greatly on the aircraft in rec flying but can be very serious. The P51 Mustang’s 2000 hp motor, under a rapid power increase to save an undershoot approach was allegedly capable of rolling the aircraft straight onto its back – ouch!

 

 

Hit the power hard and fast when you find you are behind the aircraft and trying to salvage a seriously undershooting approach and/or aerodynamic energy loss (let it get too slow) and you will invoke roll, consequent yaw and have introduced a great deal more piloting challenges that you could have avoided if you were well in front of the aircraft.

 

 

ENGINE EFFECTS #8. Gyroscopic. This primarily effects taildraggers on the ground when they are rotated into or out of the level attitude from/to the tail down attitude. Gyroscopic precession translates the vertical change of plane of the prop disc into a sideways force that consequently swings the aircraft when the wheels are on the ground acting as a pivot point. This has no effect on engine effects influencing approach control.

 

 

ENGINE EFFECTS #9 Asymmetric Blade. This is exclusive to taildraggers when on the ground and in the full three point attitude. The effect has one side of the prop disc meeting the air at a higher angle of attack than the other side, consequently producing more thrust and again swinging the aircraft around the pivot point of the mainwheels. It has no effect on engine effects influencing approach control.

 

 

NOTE: I have touched on all four of the main engine effects. I could do no less because the thread is entitled engine effects. However, Mike has qualified this in his post as engine effects pertaining to approach control – so we will now go there.

 

 

But first please a few general words. A great many aircraft (taildraggers) have been badly damaged or written off on the ground. That is directly attributable to poor piloting and in turn is attributable to piss poor instructing in the first place leaving baffled owners in the wake of ‘WTF Happened?’

 

 

The latter is wrapped up in the increasing trend towards nosewheel types where engine effects are not much of an issue so consequently the basic flying training syllabus does not treat them as it should and thus leaves a gap in the tailwheel conversion process (which is not helped by using docile types such as the Drifter that are technically taildraggers). As a further consequence instructor training is also correspondingly weak in this area.

 

 

Make no mistake about this – standards come down from the top that orders the depth of training. I had a major run-in with a former Ops Manager over this who minimised the gyroscopic and asymmetric effects as really non relevant. He half dismissed my assertation that just those two effects could totally take charge of a Thruster and swing it off landing line by 30 degrees and the pilot could not stop that happening unless preventative techniques had been prior employed that were understood.

 

 

Enough said – let us return to the main topic.

 

 

Within the context that Mike is inviting opinion on I do not see a great deal of drama. The throttles should most times be used smoothly and progressively. This in itself smoothes any engine effects to a level where they are easily controlled by rudder and do not invoke a great deal of secondary effects and consequent further control use.

 

 

The only significant effects when flying are slipstream and (to a much lesser extent on low powered aircraft) torque. Both cause yaw and secondary effect consequences but not of any major extent in a general control sense, but possibly so in an unnecessary additional pilot workload and/or distraction.

 

 

If you are in an approach control situation and have to use substantial and abrupt throttle use then you are either (a) much too far behind the aircraft, or (b) are flying in conditions beyond your experience capability to fully control (you are unable to ‘read’ the air in front of you, predict what is going to happen and have already set up appropriate techniques).

 

 

The prime effect of the engine, in approach control or general flying, is to control climb and descent. There should be no difference on approach and a correctly flown approach should have you able to fly the aircraft quite normally.

 

 

Certainly there are specific geographic/met combinations that require specific techniques but these are normally site specific, have to be learnt for the particular site and form no part of general flying skills per se – saving that you may need all of your flying skills to deal with the circumstances prevailing at the time.

 

 

I invite questions, comment or rebuttal.

 

 

Aye

 

 

Tony

 

 

[facthunter]

Situation.

 

Let me suggest a situation where the approach is going fine, the day is a bit thermally (Unstable) and you are trying to touch down not too far in ( as the strip is short). You are happy with the aspect of the strip (approach path) and you have been using a bit of power to make fine adjustments on final. The approach takes you over a bitumen road and a row of trees on the aerodrome boundary and you allow a bit of extra height to clear them safely, Everything is going fine. Then at about 100 feet you almost fall out of the sky, a glance at the airspeed (out of the corner of your eye) indicates that you are slow and you notice that as the end of the strip has moved up the windscreen somewhat and you may not make the strip.

 

This situation can only be recovered by the application of a lot (all?) of your engine thrust, and I believe that the pilot has to be ready for this sort of thing at all times on approach and to carry it out competantly. The aircraft in this situation is deficient in energy and there is only one fix.

 

The idea that airspeed is controlled by the elevators and the height by the engine is too black and white. It relates to gliders. It's never completely one or the other unless the engine is not there. If you are flying LEVEL, you control your speed by engine power. IF you are descending on a glideslope, OR any other constant angle approach you can only vary your speed with POWER. If you are climbing with maximum power(it is then, not a variable) THEN you control your speed with the elevators. This all seems fundamental to me. Nev..

 

 

[Guest High Plains Drifter]

Hit the power hard and fast when you find you are behind the aircraft and trying to salvage a seriously undershooting approach and/or aerodynamic energy loss (let it get too slow) and you will invoke roll, consequent yaw and have introduced a great deal more piloting challenges that you could have avoided if you were well in front of the aircraft.

I'd just add to that section of Tonys post (TOSOG) that if you did that with certain radials you may conversely discover engine hesitation at a critical moment () (not to mention possible engine damage)

 

Many new Ultralight pilots will go on to fly many and varied aircraft types, probably best to develop a 'considered' approch to the lernin of foundation throttle application skills.

 

 

[Guest Elk McPherson]

FACTHUNTER

 

Excellent post!

 

I love the argument about Stick or throttle controlling speed.... I suggest we go out to the runway and try it out.

 

I then sit at the threshold wiggling the elevators up and down.

 

"What are you doing that for?" asks baffled new instructor.

 

"I'm using the elevator to get some speed. When we are going fast enough, I will add some power so we can take off!"

 

 

[Guest TOSGcentral]

Excellent – we have now got the thread onto a really productive base that we can develop from and examine with some clarity in the approach control situation.

 

 

Elk – you pinched my lines because that was exactly the response I intended to give in agreements with Nev.

 

 

Nev is of course entirely correct! But I do feel that we have to be black and white to start with when establishing some foundation understanding.

 

 

Initially I strive to establish a clear concept that the aircraft is carrying two distinct energy sources which in practice are used in concert. This is why I make a clear division in the order of exercises that I choose to use which, initially, separates the engine entirely from controlling the machine’s flight attitude – the engine is left at a suitable cruise setting to provide the base energy source which the manoeuvring may be based upon.

 

 

Once the student is proficient in maintaining an attitude, which includes preventing the natural nose down pitch (and consequent increase of airspeed) when entering a turn and removing that back pressure smoothly on exit as the wings level – then engine control may be introduced.

 

 

Initially though I want the student to fully understand that from the existing energy base already established (engine RPM, nose attitude and current airspeed) that the aircraft’s climb or descent rate is varied by the throttle and the elevator is used to select a new attitude that will maintain the airspeed. This is a foundation knowledge/skill base which later approach control will be established.

 

 

What I certainly want to do is break any concept in the student’s mind that they are driving some form of car where speed is entirely controlled by the throttle. Most people these days drive and it is natural for them to transport prior experience into the new environment.

 

 

To cover the area that Nev touches on re airspeed in straight and level flight I deal with it in this way. I never teach straight and level flight as an exercise! It is a total waste of time and student money. Stability will maintain straight and level for you and if the air is too rough for Stability to cope with quickly enough then at best you are teaching ‘negative turning’.

 

 

Rather what I do is reinforce the energy base useage by establishing that the engine provides the level of energy that the cruise speed will be dependent upon. In terms of a flight exercise the student is therefore taught that via the rev counter RPM can be selected that will result in the aircraft flying at the same altitude either slowly, at normal cruise and attitude, or faster. I give them plenty of practice at that and it why I regard a VSI as essential equipment in any trainer.

 

 

When brought together I have most of the components required that will result in the student retaining full control of the machine while guiding it down an approach slope using an Aiming Point as a reference.

 

 

I do not want to go much further than that in this post until I have seen some reply comments. However I will begin paving the way ahead a little with a practical example of speed control as part of approach control and will use gliding as an example as there are some fundamental parallels to our discussion that we can draw upon here.

 

 

There are two prime ways of controlling the approach path of a glider. The method that I was taught (which may be applied directly to powered machines) is as follows:

 

 

The selected approach speed/attitude required for the prevailing conditions is selected prior to Final Turn entry with the glider in an overshoot configuration (ie it will glide at least to the upwind end of the runway if you do not do something about it from the distance/height to the intended landing point).

 

 

After Final Turn the Aiming Point is positively identified as being low in the windscreen and moving downwards. Airbrakes are then deployed, which begins slowing the aircraft, and the nose is lowered via the elevators to maintain the airspeed and move the Aiming Point back up the windscreen to the centre of vision. The approach path has now been steepened but the airspeed has not changed and all of the controls are remaining essentially still unless you wish to refine things a little.

 

 

The German gliding movement has a different technique. As the machine exits the Final Turn the Aiming Point is placed in the centre of vision and kept there by using the elevators. The glider is essentially being ‘pointed’ by use of the stick and will end up going damn fast! This is controlled by airbrake deployment and these are used to keep the airspeed at the desired approach speed .

 

 

This appears to be a simpler way of doing things but has some hiccups. The two main ones are the student is constantly fiddling with the airbrakes (and initially over-controlling which can be exciting) and also constantly has to be referring to the ASI..

 

 

But the main thing is that the procedure is ‘artificial’ and does not naturally equate to the normal control of the glider in flight. The airspeed is controlled by the elevators and the last thing you want to be doing is be deploying drag producing devices just to control you speed (unless you have damn good reason to do so).

 

 

To me the parallels between gliders and light recreational powered aircraft are exactly the same. Indeed when converting glider pilots to ultralights I simply tell the student to fly the machine exactly like a glider (but very low performance of course) and use the throttle as an ‘iron thermal’ over which the student has control of the strength. On approach do exactly what you normally do but use the throttle exactly as you would the airbrake lever. Works every time – no drama!

 

 

So – let’s have more views and feedback and we can extend this thread into the finer techniques of approach control whilst having ironed out the foundation principles first.

 

 

Aye

 

 

Tony

 

 

[skybum]

Effects of power, aerodynamic devices and speed. best demo I have seen for effects of power. RAAF fast taxi DHC-4 Carribou. Fullflap, Power on and very nose down and only zot feet off ground at less than 40kts. Also used for wheelbarrow demo at airshows. Aircraft is set in attitude with nosewheel just touching ground, mains are about a meter in air to give an idea of attitude. Power is just trickling along. End of run, power is added and aircraft starts climbing whilst remaining in same attitude and speed. Quite visual demonstration of relationship between power and rate of climb or descent. Big old radials give out a lot of indication when power is coming on.

 

 

[facthunter]

Continuing....

 

Well covered, Tony, and I agree that the planting the RWY in the windscreen and dissipating the energy by speedbrake application is CRUDE and a bit like driving bulldozers (with apologies to bulldozer drivers, who may perform their jobs with more finess than some planedrivers), but it would be an easy technique to teach, and it is a fundamentally safe procedure, as you are always in a position of excess energy. I'm not entirely happy with the idea of leaving the power at a setting as for instance I would want the pilot's hand on the throttle pretty much after turning base, also on entering a level turn of more than 30 degrees bank, where I would expect power to be added on entering the turn, and reduced on exit , and at any time when low flying ( unless the area is fairly level and free of trees etc.), or in anything more than moderate turbulence, as examples. Nev..

 

 

[Guest TOSGcentral]

Yup - no disagreement Nev except one point - I personally require the student's hand to be on the throttle ALL the time (particularly with carbs that have heavy springs and the aircraft has indifferent throttle friction devices fitted). I barely tolerate scratching and certainly not waving to the admiring girl friend below!

 

In better set up situations when on protraced cross country cruise then OK the throttle friction can be screwed up and left alone - but not when you are actually, or likely to be, controlling the aircraft.

 

That is maintaining the energy interface between flight controls and engine. Your hand has need to be on the throttle as much as it does on the stick.

 

(PS - I hope Planedriver did not read your post! ;))

 

 

[farri]

Yup - no disagreement Nev except one point - I personally require the student's hand to be on the throttle ALL the time (particularly with carbs that have heavy springs and the aircraft has indifferent throttle friction devices fitted). I barely tolerate scratching and certainly not waving to the admiring girl friend below!In better set up situations when on protraced cross country cruise then OK the throttle friction can be screwed up and left alone - but not when you are actually, or likely to be, controlling the aircraft.

 

That is maintaining the energy interface between flight controls and engine. Your hand has need to be on the throttle as much as it does on the stick.

Tony,

 

I agree completly with this post,that is what I practise at all times,it`s what I required of my students and I hope it`s what all RAA instructors teach and require of their students.

 

Frank.

 

 

[motzartmerv]

then of course there's the whole problem of guys lowering the nose to adjust airspeed at the wrong time, ie, in the flair.. Sometimes guys look at the airspeed and see its decaying and there natural reaction (with the attitude for airspeed) is to lower the nose. thereby reducing the angle of attack and loosing lots of lift...The result is a a wheeel barrow, prop strike or a bouncy landing. But if you just feed a touch of power on and maintain the attitude it workds out much better i think...

 

cheers

 

 

[Yenn]

I question the use of aspect as a major sighting aid for the simple reason that some strips have upslopes and some have downslopes. Where i fly at Rodds Bay the aspect on the approaches for 13 and 31 are vastly different, so much so that as we usually use 13, the approach to 31 seems to be a drastic undershoot.

 

If too high on the approach with a plane with good stalling behaviour it is possible to lose height very quickly by pulling the nose up and getting on the backside of the power curve for a few moments, recovery is easy if you don't trim for the nose up, but don't try it near the ground unless you know your plane very well. Just above the stall it is possible to get into serious sink figures and if held too close to the ground there will not be enough speed to be able to flare which is a serious situation to be in.

 

 

[motzartmerv]

Yenn.. i seriously question that method of loosing height . While it may work ok for you and as you said you need to know the acft well, but comon man, can u seriously say on a forum viewed by students that pulling the nose up and getting on the back of the DRAG curve is a good way to loose height??

 

Obviously different strips need different considerations. If not useing attitude then what would you say is best on a strip with a steep slope??

 

 

[facthunter]

Technique.

 

Ian, think I'd keep that for the blokes/gals who fly four landings a day minimum and have a very forgiving wing (like on a Cessna). I would slip it or take the flap a bit earlier. On uphill I might not use the flap to the full landing setting. so that is not helpfull if you get high. Sloping aerodromes are difficult to judge (till you get used to them, individually) as are approaches over water, as are displaced thresholds. All part of the learning process. and there is information out there covering most of this, but I can't recollect much of it in the general syllabus/training material. Nev..