Warbird Information Exchange

This might be a really dumb question, but did most single-engine WWII era fighters have feathering props? And if not, why not? Obviously feathering a prop on a single engine aircraft is only going to delay the inevitable, but I'm thinking that in that situation any fraction of a second you could scrounge up might be helpful.

What got me pondering this was an article I read a while back about a Mustang pilot who ended up strafing a train in France somewhere, with his engine seized (coolant system damage) and prop unfeathered. I have been wondering ever since if he couldn't feather his prop due to damage (or no oil supply?) or if the aircraft simply didn't have that capability.

Anyways, let me know if I have to fashion myslef a dunce cap for this one, but I am curious.

cheers

greg v.

Feathering a prop only keeps the engine from windmilling, and causing aerodynamic drag. On a multi engined aircraft, the drag penalty could keep the aircraft in the air, using the available remaing engine power.

One a single engined aircraft, you don't have another engine to help keep the aircraft in the air. The additional weight, complexity, and cost outweigh any possible benefit from having a full feathering prop on a single engined aircraft.

Like all rules, there are exceptions. Take a Raytheon T-6 or T-34C for instance. The PT6A engines are designed to utilize feathering props, and these are purpose built aircraft (training jet pilots), and the feathing feature is only incidental.

There have been multi-engined aircraft built without feathering props, but they are rare in todays environment.

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If God had wanted man to fly behind a flat motor, Pratt Whitney would've built one.

I'm no expert, but... The Smith owned Seafire FR.47 has a contra-rotating propeller unit and engine from a Avro Shackleton, including a feathering setup and big red button in the cockpit. In the event of engine failure, six broad blades would act like a very efficient speedbrake, so it's a big bonus to be able to feather them. It may even be just so you could see forwards! (NB: THe Royal Navy diodn't have this item, of course.) AFAIK, it's the only single engine piston with feathering. Of course...


...enter list of others below here!

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James K

"Switch on the underwater landing lights"
Emilio Largo, Thunderball.

www.VintageAeroWriter.com

On a single engine plane, when the engine fails, for whatever reason, you're going to land. Assuming a gear up landing, a feathered prop will not fold like an un-feathered prop, and will cause severe structural damage.

On the B-25, if you're landing gear up with one feathered, you're directed to unfeather. The manual says, " With propellers feathered, the tips will not bend aside on impact, but will dig into the ground, breaking the engine mounts and rupturing wing tanks, adding to fire hazzard."

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T-6F, N81857
warbirdridesusa@gmail.com

A windmilling prop causes drag. Stop it, or feather it & you gain glide performance. Ask some folks who've landed a single gear up, shut down the engine to lessen the engine damage & then overshot their landing point when the prop stopped windmilling & the sudden loss of drag allowed the a/c speed to 'surge'. Riley Rocket converted Mooneys, using the TCM TSIO-520N (IIRC), which is used on Cessna 340s & some of the 400 series, along with the same prop, still have the feathering feature, which as I understand it, is or at least was, one of the Rocket mod's 'benefits', allowing for improved glide in the event of engine failure.

Keep in mind that most single engine aircraft will go flat pitch when you lose oil pressure (opposite of a multi)...the idea being that if the engine on a single is failing, going to low pitch will give you the max power with whatever life the engine has left in it.

That said, I once had the engine in a Pitts S-2B go to idle in the pattern on crosswind when the throttle linkage broke. Yanking the prop back and going to as high pitch as possible enabled me to land without incident or really much drama at all on an intersecting runway. In fact, I was able to use the prop like a spoiler on a glider (along with a slip) to slow it down once I was assured of touching pavement...the difference in drag is quite dramatic. If the prop would have stayed flat I would have had to put it down straight ahead.

FWIW, instantly yanking back on the prop when the engine failed was something my instructor had taught me when I got checked out in a Pitts.