TAKING OFF PROCEDURES !!

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Morph
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Postby Morph » Mon Feb 27, 2006 1:42 pm

Smiley wrote: Hello Morph

True true, but lets not just talk about where and when to use it and for what reason, but also where not and when not to use it. Every action has a reaction!!
Absolutely right, this is not to be used every time, because unless to immediately neutralise the wing/stick after takeoff you will be in a stall albeit within a foot off the ground.
However, one day when you are on a muddy field, the sooner you get off the ground the better. You are going to think back and say, "hey I remmember a post somewhere where the guys used this technique to get off the ground quick.... ":wink: :D

BTW if have found that if the plane lifts off too early, i.e. barely flying and you do not neutralise the stick quick enough it just resettles back down as if you are in a normal flare.

And finally, without this sort of thing there would be nothing else to talk about which is why I am here 8)
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Postby Griffin » Mon Feb 27, 2006 1:43 pm

This is the technique taught at FAFK. I believe it was the topic of some heated debate at one of the MISASA instructors conferences. As far as I remember the reasoning is the if the student holds in the bar beyond neutral and then pushes out the trike could climb suddenly and go into an immediate stall. Any comments from Junkie or Louisvw??
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Postby Big-D » Mon Feb 27, 2006 1:45 pm

This is really quite interesting as I was debating this very subject of "position of the bar" with 2 fellow pilots on Saturday. I was taught to hold the bar 4 fingers from the profile tube and as the plane starts flying to pull back to neutral and I have never questioned this until a week ago - Dieselfan and I had a few anxious moments taking off in Mooinooi where it was pretty warm and the runway is short and we took off with maybe 20m to spare (granted Dielelfan is of normal weight and I weigh 120kg and we had 60l of petrol in the tank). This got me thinking about my take-off teqnique and is it truly the best for a short runway? The 2 guys from Saturday (one of which is an engineer who understands lift and drag and physics much better than me) reckon bar must be kept neutral and she will start to fly by herself. Anyhow, I took my ex-instructor for breakfast the same morning and he maintains that keeping the bar forward until she lifts will get you off the ground the quickest and that he has proven this time and time again in the bush where it really matters all kinds of obstacles to clear.
I am now confused indeed. I received instruction from 4 different instructors with 12000, 8000, 7000 and 1500 hours respectively and all taught me the same tegnique of pushing the bar forward and then pulling back to neutral as she takes off.
Maybe someone can answer this convincingly?
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Morph
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Postby Morph » Mon Feb 27, 2006 2:01 pm

Big D wrote: This got me thinking about my take-off teqnique and is it truly the best for a short runway? The 2 guys from Saturday (one of which is an engineer who understands lift and drag and physics much better than me) reckon bar must be kept neutral and she will start to fly by herself.
True and by the time the plane has started flying on her own you would have had a real barbed-wire tattoo.

BTW hot high and humid, and heavy weight are not a good recipe at any time especially on a short runway. Unless you needed to go far you should have reduced weight, even if it's just by halving the fuel, 20kg.

Finally, go with what all 4 intructors taught you and adapt it to suit specific circumstances where neccessary.
Last edited by Morph on Mon Feb 27, 2006 2:29 pm, edited 2 times in total.
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Postby Big-D » Mon Feb 27, 2006 2:08 pm

BTW short runways, hot high and humid, and heavy weight are not a good recipe at any time especially on a short runway. Unless you needed to go far you should have reduced weight, even if it's just by halving the fuel, 20kg.
Yip, the beauty of hindsight. Our trip was rather far but I reckon 40liters would have been enough to get home.

Couldn't agree more - Hot, high humid and heavy is a no-no
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Postby Smiley » Mon Feb 27, 2006 2:20 pm

Mmmmm, once again In think there is method in the madness, but if not respected it will bite you in the #$^%$%#!! A slow flying plane is more unstable than a fast flying plane!!
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Postby Duck Rogers » Mon Feb 27, 2006 3:38 pm

Chaz wrote:MY Question here is :- IS THAT GOOD PRACTICE OR IS IT ACCEPTABLE
Eish! Now look what you started :shock:
From what has transpired so far...the answer to your original question must then be YES, to BOTH!

Like Smiley says "Mambo Jumbo".......JUST FLY MAN!!!! :D :D

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Postby Aerosan » Mon Feb 27, 2006 4:02 pm

Hey Duckie

just a question- how far is your plane? :P
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Let's hear from the Head Of Training

Postby John Young » Mon Feb 27, 2006 4:03 pm

I put it to you that if you asked a roomful of international rugby referees to define the "official off-side line" in rugby, about 100 different views would be exchanged.

Therefore, let's ask the Head of Training Dave Daniel for objective input.

I will send him an email prompt.
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Postby Chaz » Mon Feb 27, 2006 4:10 pm

Heya Duck Rodgers !!

Only one way to put this to rest :!: :!: We have a 1.2km tarred runway at Springs. So i will start at the threshhold of 03 with bar full forward and by the end of the runway check my height. Also while rolling i will check ground speed and air speed at the point of lift. I will then do it the way ive been taught and give feed back here in the next couple of days. I know Fred Blokland for one, for those who know him is a very experienced and capable instructor is totally opposed to that manner of having the bar full forward against the profile tube on lift off.

The trike i watched on Friday morning did seem wobbly and seemed to descend first before actually lifting :shock: :shock: . As "smiley" mentioned on a turbulent, thermal crosswind day does this help.

I just think the correct manner which non of us have seemed to agree upon yet needs to be carried over to aspiring students. The bar back in neutral and let the plane get as much ground speed as possible unhindered for obvious reasons makes sense to me. I dont think its about style but what must be done and what must be done correctly must be taught :!: :!: :!:

Your's in Flying 8) 8) 8)
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Postby Big-D » Mon Feb 27, 2006 4:25 pm

Chaz - I am looking forward to the result of your experiment. I too will undertake an experiment on which take-off teqnique gives you the shortest ground roll. I watched Jenya and AlanMack testing a wing and what they do is the passenger throws a cloth (out of the props way off course) as the plane takes off. This then gets measured and I will get back to you guys on this within the week.
This would not neccesasirily then reflect the best take off procedure but could be handy for those short runway take-offs with the bluegum trees at the end :D
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Postby DieselFan » Mon Feb 27, 2006 4:38 pm

In the microlight pilots handbook, it mentions best climbing rate and best climbing angle are these not just the different ways to obtain them?
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Postby Biggles » Mon Feb 27, 2006 4:51 pm

Hi all

Was just wondering if the bar full forward will help clearing high objects or it just to get the wheels of the ground quickly.

Griffin, doing my license out of FAFK at the moment. Had a big break form lessons with work and December CT weather being so kak. Going to be back in two weeks and praying the weather has improved!!! :( Its been a while :oops: but I am pretty certain the commentary on take-off was: bar neutral (slightly back), feel the wing starting to fly, using power to climb, maybe with the bar slightly back to maintain airspeed.

I would rather be flying and climbing over the barbwire fence than wobbling close to stall on ground effects. All the footage of STOL military type aircraft I have seen they are pretty much climbing away as soon as thier undercarage leaves the ground. They even leave rotation to pretty much the last moment. I would imagine getting the wheels off the ground early would be good with bad ground though...
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Postby lamercyfly » Mon Feb 27, 2006 5:13 pm

Dear Readers of this forum.........Eish........the angels must be working overtime to look after microlight pilots taking off around SA.............. :lol: :lol: :lol:

But, on a more serious note, you all seem to still have the ability to type, so I gues you still have the use of your arms and fingers, which means that you are all still able to fly again this coming week-end :lol: :lol: :lol:

No, man, but really, on a more serious note, :lol: :lol: :lol: :lol:

O.K. O.K, Herwith my humble thoughts on this issue.

1. Face the trike into wind
2. Gee vet
3. Close your eyes
4. Open them when the rumbling stops :lol: :lol: :lol:

Hang on now, let me just dry my eyes............

Right!!

There are many ways to accelerate until rotation, both in a trike and fixed wing. (by the way, the fella that takes off with his fixed wing with the stick in his guts, is lifting off 'behind the power curve" Please check your owners manual for procedures required for short field take-off. Note that there should be procedures for different ground surfaces)

I am ashamed of my fellow instructors who only teach one method. Maybe they teach different methods, but the students forget? I don't know anymore.

For students who are in initial training, we teach the take-off roll as follows:

runway of sufficient length, nil crosswind, nil to moderate headwind, sea-level or altitude

1. Line up on centreline and stop
2. Point your feet straight ahead
3. Position the bar approximately 'one fist-length' from the aerofoil. Lean forward with your shoulders if necessary - DO NOT LOCK YOUR ARMS
4. Gradually accelerate to full power (over about 3 secs)
5. Follow centreline by gentle 'left/right' banking movements of the bar
6. Immediately the trike rotates, check the bar to achieve climb attitude.This will prevent you from flying to slowly and climbing to steeply. It will result in the 'perfect' speed for your configuration.
7. If speed gets excessive, gently check power as required.

Toward the end of dual training, just before solo, we introduce"solo-power". For this we get the student used to reducing power ever so slightly at the same time that they check the bar for climb attitude. This prevents the climb rate and attitude from being any different to what the student has become accustomed to while the instructor was on board. (Note that this is at sea level.)

The reason we teach the above rolling technique, is so that on first solo, the student does not get into the situation whereby they accelerate just a little too much before rotation, then pushing the bar forward, they go into 'heavenly' mode, get the fright of their lives, come off the power, haul the bar back in, and crash into the ground. The other scenario is where the student on first solo pushes the bar forward too soon, and just pops off the ground into a stall. Also resulting in ground strike.... The above technique which we teach, prevents both unwanted scenarios. The trike gets airborne when she is ready, and behaves with good manners.

This is by no means the only way to take off. But it is a damn good way of teaching a student. If this is all the student knows, then this is how he is going to rotate. This way, the aircraft gets airborne as soon as it has flying speed, and there is minimum undercarriage 'thrust rotation' and minimal 'heavenly zooming'.

The other techniques of ground rolling, leading up to rotation, all have their place. There are techniques for short field, soft field, and especially cross-wind.

WATCH THE PRESS. LA MERCY WILL SOON BE OFFERING THE 'TRIKE MASTERS ADVANCED FLYING CAMP'.

Please guys, let the Angels get off for a week-end :lol: :lol:
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Morph
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Postby Morph » Mon Feb 27, 2006 5:26 pm

But I'll bet the following on Chaz's experiment.

a. He will be off the ground in a lot shorter distance than he ever has been before,
b. then while in ground-effect he will pass his normal rotation point at a speed higher than he would have done on a traditional takeoff, (why :?: no rolling resistance, in ground-effect the plane is experiencing the least drag per hp produced compared to any other stage of flight, except during the decend of course, and thus will accelerate very quickly.)
c. then use the increased speed to pull up into the best rate of climb speed which will get him higher at a given point than he would have been with a traditional takeoff (The increased speed will give the climb extra impetus until the plane slows to best rate of climb. Using this technique I get a rate of climb of 1200 to 1500 fpm whereas normally I only get 900fpm solo.
d. Will have a huge grin on his face when he experiences the accelerated performance and climb. :D :wink: 8)
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