Prop Failure

[Admin]

Hi All

 

Tomorrow I will be having the prop replaced on my Gazelle with a brand new Gazelle Certified 2 Blade Wooden one. In thinking about this whilst mentally preparing for my next flight although like any work done on my aircraft I always get a LAME or for minor things a Level 2 to do the work (even oil changes) but what about the prop iteself?

 

I am going to be very very anxious for the first few hours as new props are really an unknown factor, I mean can they X-Ray wooden props for any flaws or weak grain parts, is the wood really really dried out before they make the prop, what's the failure rate of brand new wooden props etc?.

 

What I need to know is what would happen and what should I do if say the prop splits in flight, or breaks half a blade or full blade - what are the different scenarios and what would you do if any of these things happened whilst you are merrily cruising away.

 

Thanks for any comments!

 

 

[PaulN]

Ian,

 

I'm no expert here, and thank the Lord, I have no experience with this. However, from conversations I've had re prop failure it seems that the first thing one is likely to experience is severe vibration. And in bad cases there is a real risk of shaking the engine from its mounts. From what I understand, and the thinking I go through in the air, is that the first reaction should be an immediate closing of throttle and shut down. After that of course comes the inevitable forced dead-stick landing. Not a nice thought, however, a controlled forced landing is a much better option than losing lots of forward weight and spiraling in tail first :yuk:.

 

Just my thoughts,

 

Paul

 

 

[Guest Crezzi]

I've had a passenger "lose" his helmet in flight. It blew off as he was looking out to the right of the trike, hit the prop and got fired forwards and upwards to the left of the plane (according to the passenger).

 

First I knew about it was the appalling vibration - I honestly thought the engine was going to come off its mountings. In the short time it took me to kill the engine, the vibration broke all the radiator mounts, shook most of the coolant into the overflow tank and popped the exhaust headers out of the sockets (but still held on by the springs).

 

Not killing the engine just wasn't an option but the dead stick landing was uneventful - thats why I still practise them (for real not idle).

 

One of the prop blades (it was a Warp Drive) had lost about 2/3 of thickness for almost its entire length. With 1 finger you could move the tip about 6inches for and aft. I was amazed that the remains had enough structural integrity to not completely detach. The fragments had gone through the sail several places but only holes not tears.

 

The 912 was professionally checked and there was no internal damage.

 

The helmet luckily didn't hit anyone or anything on the ground and was later returned by somebody who saw it falling. They were a bit freaked as they weren't sure whether there would be a head in it.

 

Not an experience I would wish on anybody (or to repeat).

 

Cheers

 

John

 

 

[Guest Fred Bear]

Scary John :ah_oh::confused:

[facthunter]

Wooden props

 

I've always felt that a wooden 2 blade prop is the simplest most reliable smoothest thing you can put on an aircraft, & I personally know of no failures except where contact was made with something solid or sustained flight in heavy rain/ hail. Reliability is considered to be improved by increasing the number of laminations.Tip speed and efficiency are usually a bit less than metal but with the coatings available these days, perhaps not so much..N..

 

 

[pylon500]

Gazelle Certified 2 Blade Wood

Just don't expect the same performance as you got from a composite prop.

Always remember to store the plane with the prop horizontal to maintain balance.

 

Arthur.