Why feather metal props for gear up?

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Dronepiper
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Why feather metal props for gear up?

Post by Dronepiper »

Ok…so this might be a really stupid question, but I am genuinely curious by your responses.

I could understand why you would want to feather wooden/composite props for a gear up landing (Splintering), but why bother for metal props as they just bend?

I know this sounds silly, but wouldn’t you rather just write the plane off and get the insurance money? If its a belly scrape, chances are its not going to be expensive enough to get written off, but it still gets counted as an insurance claim. Now you have an airplane with damage history that will he harder to sell.

If you also strike the props, you are pretty much destroying the engines, which will definitely lead to a write off.

This might sound really stupid, but it’s something I genuinely think about. I personally think my boss would rather have his insurance money then a half damaged airplane.
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PilotDAR
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Re: Why feather metal props for gear up?

Post by PilotDAR »

Personally, I don't consider insurance payoffs when I fly, I consider my sense of care for people and equipment. So, if I can take simple action which reduces injury/damage/risk, I'll do that. If the result is a repairable airplane, rather than a write off, I think I've done a better job. If the insurer would replace a write off, they would repair damage. It will be a lesser claim for repair, and a lesser hit to the policy holder's claims record.

Airplanes are not always as easily replaceable as could be hoped, so sometimes, it'd be nicer to have the plane of your choice repaired than to have to go to the effort to have to find another one with the money from the insurance. And, I would want my fellow pilots, when considering (and probably viewing the event on Youtube) to think to themselves; "well he did his best in a difficult situation", Rather than; "He just drove it onto the runway as if he didn't care".

Bent or below limit propeller blades are scrap. Some wood composite blades can be rebuilt.
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Bede
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Re: Why feather metal props for gear up?

Post by Bede »

I don't blame you for thinking this way but it's also why our insurance rates keep climbing. Kind of like the guys with old fabric planes that take their planes outside when a thunderstorm is approaching hoping for some hail damage and a few fabric job.
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digits_
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Re: Why feather metal props for gear up?

Post by digits_ »

On most planes with more than 2 blades, I would intentionally not feather the props, unless the poh says otherwise.

A fine blade will curl and be a write off, a feathered blade will create much more force on the engine axis (crankshaft or turbine shaft). No point saving a couple of blades but destroying your engine in the process.
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Pacqing
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Re: Why feather metal props for gear up?

Post by Pacqing »

When a piston engine seizes in flight you don't really have much choice as to blade position. If its vertical and the gear is up chances are the blade will hit mother earth.
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Big Pistons Forever
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Re: Why feather metal props for gear up?

Post by Big Pistons Forever »

The scenario as I understand it is you have a twin engine aircraft where you are unable to extend the landing gear. The only criteria that matters is achieving a safe belly touchdown in a slight nose up attitude at the chosen touchdown point. To do that you want power available until the flare so you can adjust the flight path as required. When you start the flare pull both mixtures to idle cut off and fly the aircraft on to the runway. Do not try to hold it off as you don't want the touch down point near the tail as the nose will slam down increasing aircraft damage.

Some considerations

1) With the gear up there will be less drag so your approach path will be flatter than a normal landing so don't start out high

2) In a low wing aircraft there will be very strong ground effect so don't let the aircraft float off the end of the runway, start your flare at the numbers and fly it on.

3) You have power available so don't be afraid to go around if the approach isn't perfect

4) Consider an approach flap vice landing flap selection to reduce damage to the flaps

Finally have seen pilots flying twins with two blade props advising feathering the props and using the starter to bump the props level so they won't hit the ground. Personally I think this is foolish and I know of one pilot that tried this only to get so distracted with trying to level the blades he got low and hit short of the runway and destroyed the aircraft as well as being lucky in avoiding a serious injury to himself
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Last edited by Big Pistons Forever on Mon Sep 13, 2021 10:55 am, edited 2 times in total.
Cliff Jumper
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Re: Why feather metal props for gear up?

Post by Cliff Jumper »

I always thought the reason you feathered the props once in the flare (in this scenario) was so that they would reduce RPM faster and would come to a stop sooner (compared to not being feathered).

Regardless of propeller type, I'd rather they hit the ground stopped as opposed to flinging around at ~1500 rpm.
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