Simviation Forum - Perfect Gear-Up Landing

Reply #15 - Dec 22^nd, 2006 at 8:13am

Chris_F Offline
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I don't think you'd frag an engine by digging a prop in but the damage would likely be reduced by shutting 'em down before landing. At the very least you'd only bend up two prop blades versus all of 'em by shutting down. After all, at least one of 'em is gonna be sticking straight up and free of the runway.

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Reply #16 - Dec 22^nd, 2006 at 8:54am

expat Offline
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Chris_F wrote on Dec 22^nd, 2006 at 8:13am:

I don't think you'd frag an engine by digging a prop in but the damage would likely be reduced by shutting 'em down before landing. At the very least you'd only bend up two prop blades versus all of 'em by shutting down. After all, at least one of 'em is gonna be sticking straight up and free of the runway.

You dig a prop in on and engine that is running not matter if it is metal or wood, gas turbine or piston, the shock loading to the engine will be far greater than anything it was designed to do. The only place that such an engine can go to is the bin or a shop. Either option is going to be a pain in the wallet. Not only that, but you do dig in a prop (in this example), the LBA, CAA, FAA (depending on your country) will want to know about it and that will lead to questions such as what are you going to do with that aircraft now and please produce and overhaul certificate for that engine before it takes to the sky again, also your insurance will probably want to see it before you fly it too.

Matt

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Reply #17 - Dec 22^nd, 2006 at 9:23am

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I heard a story about a Blenheim in North Africa when evading an Me109 flew so low against the desert floor that at one point the props dug six inches into the sand. As they were still turning at maximum revs the tips of the prop blades bent themselves forwards. The resulting lack of resistance then caused the engines to rev higher and caused the Blenheim to fly faster. After this the other pilots in the squadron had to be physically restrained from sawing six inches off the prop blades on all their aircraft.

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Reply #18 - Dec 22^nd, 2006 at 9:31am

expat Offline
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Woodlouse2002 wrote on Dec 22^nd, 2006 at 9:23am:

I heard a story about a Blenheim in North Africa when evading an Me109 flew so low against the desert floor that at one point the props dug six inches into the sand. As they were still turning at maximum revs the tips of the prop blades bent themselves forwards. The resulting lack of resistance then caused the engines to rev higher and caused the Blenheim to fly faster. After this the other pilots in the squadron had to be physically restrained from sawing six inches off the prop blades on all their aircraft.

I would want to read about that one. Can't see it myself, but that is not to say it did not happen. If an object is moving forwards and at speed and then touches the ground, how will said object bend in the direction of travel? Sound like a military urban myth.

Matt

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Reply #19 - Dec 22^nd, 2006 at 10:03am

Woodlouse2002 Offline
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I saw it told by an old pilot on a documentry. Can't remember which now though.

Woodlouse2002 PITA and BAR!!!!!!!!&&&&Our Sovereign Lord the King chargeth and commandeth all persons, being assembled, immediately to disperse themselves, and peaceably to depart to their habitations, or to their lawful business, upon the pains contained in the Act made in the first year of King George the First for preventing tumults and riotous assemblies. God Save the King.&&&&Viva la revolution!

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Reply #20 - Dec 23^rd, 2006 at 12:29am

beaky Offline
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expat wrote on Dec 22^nd, 2006 at 9:31am:

Woodlouse2002 wrote on Dec 22^nd, 2006 at 9:23am:

I heard a story about a Blenheim in North Africa when evading an Me109 flew so low against the desert floor that at one point the props dug six inches into the sand. As they were still turning at maximum revs the tips of the prop blades bent themselves forwards. The resulting lack of resistance then caused the engines to rev higher and caused the Blenheim to fly faster. After this the other pilots in the squadron had to be physically restrained from sawing six inches off the prop blades on all their aircraft.

I would want to read about that one. Can't see it myself, but that is not to say it did not happen. If an object is moving forwards and at speed and then touches the ground, how will said object bend in the direction of travel? Sound like a military urban myth.

Matt

Prop blades under power always bend forwards in a strike. It's the A of A of the blade that does it. It really twists more than bends, at least intitally. The back side of the blade makes contact, and the force of the crankshaft torque very suddenly meeting the resistance of the dirt or whatever causes the tip of the blade to "want" to go in the opposite direction... so, overall the distortion is forward.

This is how crash investigators can determine immediately if a crashed plane was developing thrust or not on impact, in most cases. If they're not under power, the blades will always bend back.

Interesting... I was looking for a pictue that shows this, and found a sort of in-between example... the engine was near idle (taxiing) when the brakes locked and this Corsair nosed over... with the wide blades set at coarse pitch, they bent sideways...

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Reply #21 - Dec 23^rd, 2006 at 12:56am

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Well I would like to say that was a pretty good landing considering the stress the pilot had to be going through right then. Also, you always have to love the retarded people posting comments on videos like this such as....

But wouldn't that put skid marks all over the
bottom of the plane? Wouldn't it have been easier to put the landing gear down??

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Reply #22 - Dec 23^rd, 2006 at 1:09am

skysurfer2010 Offline
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beaky wrote on Dec 23^rd, 2006 at 12:29am:

expat wrote on Dec 22^nd, 2006 at 9:31am:

Woodlouse2002 wrote on Dec 22^nd, 2006 at 9:23am:

I heard a story about a Blenheim in North Africa when evading an Me109 flew so low against the desert floor that at one point the props dug six inches into the sand. As they were still turning at maximum revs the tips of the prop blades bent themselves forwards. The resulting lack of resistance then caused the engines to rev higher and caused the Blenheim to fly faster. After this the other pilots in the squadron had to be physically restrained from sawing six inches off the prop blades on all their aircraft.

I would want to read about that one. Can't see it myself, but that is not to say it did not happen. If an object is moving forwards and at speed and then touches the ground, how will said object bend in the direction of travel? Sound like a military urban myth.

Matt

Prop blades under power always bend forwards in a strike. It's the A of A of the blade that does it. It really twists more than bends, at least intitally. The back side of the blade makes contact, and the force of the crankshaft torque very suddenly meeting the resistance of the dirt or whatever causes the tip of the blade to "want" to go in the opposite direction... so, overall the distortion is forward.

This is how crash investigators can determine immediately if a crashed plane was developing thrust or not on impact, in most cases. If they're not under power, the blades will always bend back.

Interesting... I was looking for a pictue that shows this, and found a sort of in-between example... the engine was near idle (taxiing) when the brakes locked and this Corsair nosed over... with the wide blades set at coarse pitch, they bent sideways...

[img]

i've never seen that before. i've seen two gear ups before, one a mooney and one a seneca. both planes were producing power and the props bent backwards. i had pictures of the seneca, but i can't seem to find them now...

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Reply #23 - Dec 23^rd, 2006 at 6:12am

Woodlouse2002 Offline
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I suppose it depends on how fast the prop is turning. This Blenheim had the throttle to the wall when it's props touched, and as the sand was so much thicker than the air they pulled themselves forward and bent.

Woodlouse2002 PITA and BAR!!!!!!!!&&&&Our Sovereign Lord the King chargeth and commandeth all persons, being assembled, immediately to disperse themselves, and peaceably to depart to their habitations, or to their lawful business, upon the pains contained in the Act made in the first year of King George the First for preventing tumults and riotous assemblies. God Save the King.&&&&Viva la revolution!

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Reply #24 - Dec 23^rd, 2006 at 9:46am

expat Offline
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Live and learn Shocked

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Reply #25 - Dec 23^rd, 2006 at 12:38pm

skysurfer2010 Offline
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Woodlouse2002 wrote on Dec 23^rd, 2006 at 6:12am:

I suppose it depends on how fast the prop is turning. This Blenheim had the throttle to the wall when it's props touched, and as the sand was so much thicker than the air they pulled themselves forward and bent.

weird. i just have to see it to believe it. that concept bends my mind. both gear ups i saw were with the engines at an idle for landing. the mooney blatantly forgot gear and by the time i shouted it out on tower frequency we were seeing sparks. the seneca had the gear colapse shortly after touchdown.

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Reply #26 - Dec 23^rd, 2006 at 1:43pm

alrot Offline
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Beaaaauuuutiful landing (better even without the gear down Grin

) and I love this site never seen metacafe before Shocked

,Cools videos and faster than youtube Cool

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Reply #27 - Dec 23^rd, 2006 at 3:48pm

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What a textbook landing. There wasn't anywhere he could have improved that. Roll Eyes

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