Short field???
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Short field???
Its been a few years since I flew a light single but lets hear all your ideas for a really short field take off.
I once got a cherrytree out of a field after a forced landing by starting the take off run at 90 degrees to the proposed t/o run and turning into wind at around 15 mph. That seemed to work out pretty well although the strain on the noseleg must have been a bit ... ummm... Also I have seen people with the donkey at full chat holding on the brakes for about 20 seconds. Surely this would cause cavitation in front of the prop and nullify the effect of the 'full power/brakes on thing.
Over.
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First off, if the margins are that close, then should you really be attempting it?
I've heard of circular take-offs in sea-planes, but wouldn't care to try more than a modicum of direction change at speed (have you tried Baxterly strip - N of Birmingham?).
Propellers don't cavitate, only liquids can do that, and you wouldn't gain much from saving the 'spool-up' time on a piston engine.
One technique that I've had demonstrated to me, although not necessarily recommended, is to accelerate flaps-up/tail-up and when just above Vsfe (or just before you reach the upwind hedge) apply max lift flaps and rotate - easier with manual than electric flaps.
This should reduce the ground roll, but will probably also reduce the initial climb gradient and will only work if you use the reduced speeds for the higher flap setting.
I've heard of circular take-offs in sea-planes, but wouldn't care to try more than a modicum of direction change at speed (have you tried Baxterly strip - N of Birmingham?).
Propellers don't cavitate, only liquids can do that, and you wouldn't gain much from saving the 'spool-up' time on a piston engine.
One technique that I've had demonstrated to me, although not necessarily recommended, is to accelerate flaps-up/tail-up and when just above Vsfe (or just before you reach the upwind hedge) apply max lift flaps and rotate - easier with manual than electric flaps.
This should reduce the ground roll, but will probably also reduce the initial climb gradient and will only work if you use the reduced speeds for the higher flap setting.
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Unless you’re test pilots, I’d advise you to use only the techniques specified in the POH.
The POHs for most light A/C I’ve flown recommend applying full power against the brakes before commencing a short-field take off. If there’s a chance of the nosewheel digging in to the ground while doing this, then I’d say the field is too soft to attempt a take-off anyway.
Turns during the take-off run and mucking about with flap settings—especially in marginal conditions—are, IMHO, recipes for bent aeroplanes.
Safe flying.
HP
[This message has been edited by Horsepower (edited 15 November 2000).]
The POHs for most light A/C I’ve flown recommend applying full power against the brakes before commencing a short-field take off. If there’s a chance of the nosewheel digging in to the ground while doing this, then I’d say the field is too soft to attempt a take-off anyway.
Turns during the take-off run and mucking about with flap settings—especially in marginal conditions—are, IMHO, recipes for bent aeroplanes.
Safe flying.
HP
[This message has been edited by Horsepower (edited 15 November 2000).]
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Seen it - done it.
We used the round-the-pole technique for launching anti-aircraft missile/gun target drones. (Recovery was by parachute onto the beach).
By far the most fun was when the line snapped just before the drone reached flying speed....
Don't like to think what it would feel like in a manned aircraft though.
We used the round-the-pole technique for launching anti-aircraft missile/gun target drones. (Recovery was by parachute onto the beach).
By far the most fun was when the line snapped just before the drone reached flying speed....
Don't like to think what it would feel like in a manned aircraft though.
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1 Consult the POH and calculate the distance required, factoring in runway surface type, contamination, wind strength/direction, density altitude etc.
2 Then consider the fact that these figures were achieved in a factory fresh a/c and a manufacturers test pilot - what condition is your a/c in and how good a pilot are you? Factor accordingly
3 Then decide whether the field is long enough for a successful departure
4 If it is, the POH will give you the best procedure to get out safely. If not, get help!
This may not be sexy/macho aproach, but at least you'll be legal and your insurance valid ... and you will increase your percentages of being an old, rather than bold pilot
2 Then consider the fact that these figures were achieved in a factory fresh a/c and a manufacturers test pilot - what condition is your a/c in and how good a pilot are you? Factor accordingly
3 Then decide whether the field is long enough for a successful departure
4 If it is, the POH will give you the best procedure to get out safely. If not, get help!
This may not be sexy/macho aproach, but at least you'll be legal and your insurance valid ... and you will increase your percentages of being an old, rather than bold pilot
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I am old but not (very) bold these days. The incident in question was the only alternative to removing the cherrytree from the field by road. It was a very nice field, recently harvested but by my calculations rather too short for comfort, hence the scenic route for take off. By the way, it wasn't me who put it in there.
Also, I seem to recall from physics that air IS a liquid as are all gases really.
Also, I seem to recall from physics that air IS a liquid as are all gases really.
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I don't think that a simple understanding of some basic physics is pedantic.
The original point was regarding propellers and cavitation. Cavitation occurs in a liquid due to its incompressibility and phase change with pressure. A ship's propeller can cavitate due to the pressure drop on the surface and the resulting vapour bubbles on the surface can cause enough stress to rip metal away. The same goes for the LP fuel pump on a turbine aircraft if you shut it off before the engine has stopped.
A stationary propeller at high power however only risks damage from the increased risk of FOD. It may well be stalled, but thats an altogether different thing to cavitation.
The original point was regarding propellers and cavitation. Cavitation occurs in a liquid due to its incompressibility and phase change with pressure. A ship's propeller can cavitate due to the pressure drop on the surface and the resulting vapour bubbles on the surface can cause enough stress to rip metal away. The same goes for the LP fuel pump on a turbine aircraft if you shut it off before the engine has stopped.
A stationary propeller at high power however only risks damage from the increased risk of FOD. It may well be stalled, but thats an altogether different thing to cavitation.
