Why do we do it that way ?
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Why do we do it that way ?
After much debate with a friend of mine I cannot answer his question, so I thought I would see if anyone can help.. .. .My friend is a 10,000 hr ish fixed wing instructor and has ingrained in his brain, Power Attitude Trim to enter a climb. . .. .When flying with me recently he asked why helicopter pilots fly Attitude Power Trim to enter a climb.. .. .Obviously his method will work in a helicopter, so why is it that way around.. .. .[Steps back and awaits much ridicule <img border="0" title="" alt="[Confused]" src="confused.gif" /> ]
Joined: Jan 2001
Posts: 420
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From: AB, Canada
PAT, APT, etc. is a good way to learn how to fly. After a while, you know what is required in your machine to achieve the desired effect.. .. .I always preferred Attitude + Power = Performance, but we're often taught at the beginnning that pitch controls speed and power controls altitude change (there's a good reason why it's taught this way...a different thread). With that in mind, to enter a climb you would want to add power. Of course a change in power means a change in attitude will be required, therefore an attitude change will be needed. Thus P-A-T to enter a climb.. .. .On the helicopter we're much more used to adjusting all other controls after a slight change in another. Also, a fixed wing pilot may think that the power is not as immediately available after demand in a helicopter. So while you may have been adding power and forward cyclic at the same time, he may have seen it as A-P-T.
Joined: Nov 1999
Posts: 42
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From: Australia
Veeany and heedm,. .. .Not quite sure about your training examples but the both fixed winf and helicopters use A'P'T' for climbing (including recovering to S&L from the climb) and P'A'T' for descending.......however, whilst this is the routine for training, in the real world the three components are seperated by only micro seconds in real time..... .In both, to establish the climb, the routine is ATTITUDE.....adopt the climb attitude (attitude being airspeed).....POWER...the desired climb power (usually full for lighties)...Trim..trim the aircraft or in the case of a helicopter...BALANCE. <img border="0" title="" alt="[Razz]" src="tongue.gif" />
Joined: Jan 2001
Posts: 3,008
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From: North Queensland, Australia
Depends whether you're at the speed you want to be at!. .. .To my mind, the way to operate anything, fixed or plank wing, is to set attitude by looking at it whilst adjusting power initially by feel and then adjusting by glances inside, and balance (and trim if applicable).. .. .For the sake of argument though, let's say you're S&L at 100 kt and want to climb at 80 kt.. .. .RW: Set climb attitude and power simultaneously. Balance. Speed will bleed back, adjust attitude as required to maintain.. .. .FW: Same as above.. .. .Hmmmm....
PPRuNe Enigma
Joined: Feb 2001
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From: Scotland
Other way round.. .. .Start from 80 kt cruise. Selecting 60 kt Attitude will initiate the climb. Then you increase Power to get the rate of climb you want, and finally Trim the aircraft.. .Initiating the climb by increasing power whilst maintaining the 80kt attitude would require more power and much less efficient.. .. .Again from 80kt cruise, reducing power and maintaining attitude will initiate the descent. To start descending with an attitude change implies diving the aircraft - not a good plan.. . . . <small>[ 27 March 2002, 21:45: Message edited by: Grainger ]</small>
Joined: Nov 1999
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From: Australia
Arm out the window.......let's look at a C152 per se and look at the procedures for initiating a climb...assuming you are flying around at the cruise of say 95 knots.. .S&L at 95 knots...we climb at 70 and full power.. .Firstly, select the desired climb attitude (70 knots which will require the nose to be raised) Then slect full power (we climb in the C152 at full power) and then trim the aircraft. (A'P'T'). .To initiate a descent, let's say from the cruise to a 70 knot descent.. .S&L at 95 knots, reduce power to 1500RPM, select desired attitude, 70 knots which will require the nose attitude to be maintained until the a/c slows to 70 knots and then usually 'checked' to maintain the desired speed and then trim the aircraft. (P'A'T') APT is used for establishing a climb OR for recovering from a climb whilst PAT is used for establishing a descent OR recovering from a descent. Naturally, for the experienced pilot, all of this occurs pretty-much simultaneously however, for the Studes, it has to be taught initially in the three distinct stages for appreciation purposes.. . <img border="0" title="" alt="[Razz]" src="tongue.gif" />
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I should have made it clear earlier that we were talking about flying from an instructors point of view, i.e I was teaching him as I was taught on my instructor course.. .. .I agree that once experience builds it all happens at once.. .. .Keep the replies coming this is all very interesting.. .. .I thought it may have been an historical thing, as you guys have proven that it does work both ways.. .. .Thanks. .. .Vee
Joined: Jan 2001
Posts: 3,008
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From: North Queensland, Australia
I see where you're coming from, Vortex, but I believe teaching attitude, power and balance separately should be limited to a demo and a few tries.. .From then on, I'd advocate getting them to do it all together, to develop the feel. Naturally there's a fair bit of close monitoring to make sure they're not going to overtorque or whatever, but why not teach as we want to see people end up doing?. .Obivously descent at a lower speed than the cruise is a separate case where you want to bleed off speed before setting off down the slope.. .My aim in all this is to try and get the eyes outside as much as possible.
