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Old 8th May 2012, 18:04   #81 (permalink)
 
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EGKB: Think back to when your instructor was teaching you how to do forced landings. Here, elevator definately has to be used to control airspeed since power (by definition is not available) So, ingraining this connection is a safe basic technique which can ALWAYS be applied. Now, fast forward to circuit work and now you are adding power to achieve a desired glidepath angle to land.

As many others have pointed out, other techniques also work but in the early days the elevator/speed connection is the easiest consistant way to go to cover normal + forced landings.
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Old 8th May 2012, 18:19   #82 (permalink)
 
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My autopilot does an amazing piece of work flying the ILS of course it pitches for speed and I have to use thrust to control the descent
As stated both arguments are not correct.
Take the situation where you are on the glide and hit a bad area of sinking
Air. You are now low and slow do you pitch further into the trees for speed or use power.
It is all about managing the energy available to you from the power unit and airframe and being aware of how to play both.

Pace
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Old 8th May 2012, 18:22   #83 (permalink)
 
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My autopilot does an amazing piece of work flying the ILS of course it pitches for speed and I have to use thrust to control the descent
As stated both arguments are not correct.
Take the situation where you are on the glide and hit a bad area of sinking
Air. You are now low and slow do you pitch further into the trees for speed or use power.
It is all about managing the energy available to you from the power unit and airframe and being aware of how to play both.
But the less engine power you have right down to no engine in a Glider the more pitching for speed takes dominance

Pace
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Old 8th May 2012, 18:25   #84 (permalink)
 
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I have about 25 years on gliders so maybe some ingrained habits are coming out in my power flying. Never thought of that before.
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Old 8th May 2012, 18:50   #85 (permalink)
 
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Quote:
Originally Posted by thing
I don't really understand the 'push forward for glideslope' point of view when it seems better to just reduce power and let the nose sink.
It would also depend how fast you're flying the ILS wouldn't it? - up here, I've been doing them at 120kts down the glideslope to keep the speed up as there is *always* a queue of CAT and helicopters waiting to get in, and keeping the speed up helps the ATC guys with sequencing.

At 120 kts, with about 1900-2000rpm set on a 172, you definitely push for the glide. I flew an NDB-ILS at Dundee today at 80kts and flaps 10, and that let me use the more traditional way.
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Old 8th May 2012, 19:05   #86 (permalink)
 
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You know, I'm wondering whether EGKB is suffering from the traditional "rush the student through Ex 4-9 scenario"?

If someone had really taught him about secondary effects, how to handle the aircraft at various speeds, how to manage energy and how to set-up and manage descents, maybe he wouldn't be in the position where he is still thinking about the basics during approach and landing.

I'm sure there are a load of instructors out there who, like me, cry when they find that their student has reached circuits about 5 hours too early.
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Old 8th May 2012, 19:06   #87 (permalink)
 
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We always fly them at cruise speed+ as well for the same reasons. Apart from anything else the control response is obviously better.

Must be hell of a 172 if it manages 120kts at 1900 rpm
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Old 8th May 2012, 19:43   #88 (permalink)
 
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180HP fuel injected 172S - goes like a moon rocket compared to a 100HP 1974 M. (and it is descending at 500 fpm, which helps).
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Old 8th May 2012, 19:54   #89 (permalink)
 
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CGB has maybe hit it on the head.

Again I'll put it in the simplest terms. Cessna 152/172 final approach, full flap, trimmed for correct speed. Put on full power and it will pitch up and SLOW DOWN.

Get it now?

D.O.
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Old 8th May 2012, 20:08   #90 (permalink)
 
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What happens with aircraft which pitch down applying full power

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Old 8th May 2012, 20:26   #91 (permalink)
 
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Quote:
Originally Posted by Pace View Post
What happens with aircraft which pitch down applying full power

Pace
I have owned shares in three that did that - a Thruster TST and before that a Eurowing Goldwing and an Ultraflight Spectrum. Both had very high thrustlines so increased power increased trim speed.

In the Thruster and Spectrum actually it worked rather well, the aircraft wouldn't quite stall with the throttle closed, but in level flight the aeroplane would generally stay roughly level with changes in power, changing speed only - at-least for around 50-80% power. In both to fly a glide approach, you did have to positively hold the stick forward to fly an appropriate speed - not an uncommon experience in weedhopper derived microlights.

The Goldwing was actually quite dodgy, and would never get certified now. If you stalled it with power at idle, it wouldn't recover without power - the elevator alone wouldn't do it. I tended to land it with moderate power then, leaving the stick in the middle, flare by closing the throttle which pitched it up towards the stall whilst it sunk onto the ground. (A glide approach in the Goldwing neeed the stick virtually on the front stop).


But still, in all of those, it was stick for speed and power for rate of descent on approach (Unless you wanted a very high speed approach in the Goldwind - very high in that deeply disfunctional aeroplane being anything above about 55 knots). But all three you tended to hold the stick forward to maintain approach speed. (None had pitch trimmers you'd want to take home to meet your mother.) Ditto the original Chotia Weedhopper that the Thruster was loosely based upon, and I've had the privilege of flying a few times, same again the AX3, AX2000 and X'Air which were later developments in the same family.

The advantage of all these aeroplanes is that at-least a full power go-around tends not to stall you into the ground.

G
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Old 8th May 2012, 20:52   #92 (permalink)
 
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Genghis

A lot of jets pitch down too But going back to the original question you pitch for potential energy from the airframe which has to mean a loss of altitude to get that energy and you power for energy from the engine.
In my minds eye elevator and throttle are both connected to an energy source which is available to the pilot.
In some situations you need more from one less from the other or max from both.
So both pitch for speed or power for speed are false statements unless you happen to be a glider pitching for speed.
I think it is misleading to not train pilots to use all the controls and energy sources available to them.
Using one method is false training although I fully understand pitching for speed with students in low powered aircraft but it is still incomplete training.

Pace
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Old 8th May 2012, 21:19   #93 (permalink)
 
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D.O.

But obviously if you apply full power you'd OBVIOUSLY stop it pitching up by pushing on the yoke. Who does things 1 by 1? It's all simultaneous!!
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Old 8th May 2012, 22:31   #94 (permalink)
 
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Quote:
The runway is at 4000 ft msl, aircraft is at gross weight and the air temperature is 35 C.
I know this is not the correct answer but I had to laugh when I saw that..... This is England after all...

I do appreciate that people from different parts of foreign land have to fly under those conditions.
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Old 9th May 2012, 07:15   #95 (permalink)
 
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DO

Doing lots of glide approaches ? Other than practicing forced landings I never see the logic or benefit of glide approaches in SEP.
There are far more benefits to a powered approach even in SEP!

Pace
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Old 9th May 2012, 07:16   #96 (permalink)
 
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You will be doing lots of glide approaches. You will have to control your speed with the elevator. As one poster has already pointed out this must be second nature.

If the pilot in the AF Airbus had remembered that all these people would still be here today.

D.O.
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Old 9th May 2012, 08:30   #97 (permalink)
 
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D.O.

I know how to control the speed using the elervator, I'm just saying it's a waste of time and very backward when you're engine is on and giving you power. Yes, glide approaches it wil be mandatory, as I've done a couple so far. And decents as well, maintaining 65 knots requires nose up/down movement... not hard

But that's not my point, my point is when the engine is working and you have power, why not use it...
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Old 9th May 2012, 08:46   #98 (permalink)
 
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EGKB

Its NOT a waste of time using pitch to control speed or than it is to use power to control speed.
You have two energy sources pitch for that energy power for that energy ignore one at your peril!

Pace
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Old 9th May 2012, 08:50   #99 (permalink)
 
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It's not about only considering POWER!

I's about doing everything simultaneously, not about using one or the other.
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Old 9th May 2012, 08:56   #100 (permalink)
 
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You've had about 100 posts of valid reasons to learn and use the tried and tested, standard, taught technique rather than devising your own methods on the basis of zero experience. Here's another one.
  • You want to develop instinctive reflexes for controlling the aircraft correctly under all circumstances. You can't be switching from one method to another under times of stress like an engine failure.
  • Speed control of SEP type aircraft is far more directly and responsively controlled by pitch attitude than by throttle.
  • Pitching up to correct vertical profile in a low and slow situation in an SEP aircraft is potentially dangerous.
You do not yet know it all, and will make your flying training easier, more successful, cheaper and quicker by ABSORBING what you're being taught and not going freestyle. 4 landings and PPL pre-solo stage is as close to zero flying experience as you can get. Some of us with far greater experience are still actively trying to absorb information from our trainers and senior colleagues. In aviation, unless you are a test pilot, there is rarely a need to deviate from conventional wisdom which has often been hard learned over a very long time. Good luck to your instructor!
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