Can you weld a propeller blade from 120 degrees to 180?

Question

My uncle flew for Mission Aviation Fellowship (maf.org) for a university in Texas, and I believe that he was flying a Cessna to the Amazon (among other places). He actually knew Jim Elliot (who went to the Waodani of Ecuador), the martyr about which the movies "Beyond the Gates of Splendor" and "End of the Spear" were made. He had landed in the Amazon and one of the vanes of his 3-vane propeller broke and flew somewhere off into the jungle. So he got the welder out of the back of the plane, and cut off one of the remaining two vanes and welded it back on at 180 degrees to the one remaining vane. Then he took off and flew home. I love this story, but I always wondered...

How often does a propeller vane just fly off like that?

(And how challenging was that repair?)

Finally, was there any maintenance that would have prevented propeller breakage?

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EDIT 1:

From a page from his own memoir that I found online (search for Strash), I found that he definitely flew a Cessna 206 while in the Congo near Kinshasa (then Zaire) in Africa.

Before he worked in Africa, he worked in Suriname in South America, which, indeed, is considered to be part of the immense Amazon jungle. I don't yet know the specific plane he flew while he was there, but a direct contact at the MAF tells me it may have been a Cessna-185 or a Cessna-206.

My mom seemed to recall the story clearly (even though she's 83 and bedridden and I'm caring for her 24/7). Mom said that there was a tree branch that was hit during takeoff, which took off the blade.

If I can get a copy of Uncle John's memoir, the story may be in there.

Bottom line, I know the story was actually told because I received it personally while in his presence and he would have set the record straight at that time if it didn't happen. My recollection of the details may be fuzzy (meaning Amazon or Congo) because that was perhaps approximately 1990 when he visited us in New Jersey.

When this story took place, he may have been in either of those two places, Suriname or Congo.

Here is an early picture of my uncle from his yearbook online, before he became a full professor. He worked both at the MAF, and as a professor teaching Aviation at LeTourneau University, Aviation Technology division.

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EDIT 2:

I have to apologize... My story was probably wrong all along. Contacting someone related to MAF directly yielded what I consider to be a more realistic story, which I include here because it's interesting in its own right:

I was unable to verify your uncle’s propeller accident, but when asking around, one person remembered a similar story but it involved John flying a Cessna 185 in Africa where he lost a propeller tip (no welding involved). In order to fly the plane to an MAF repair base, he reportedly sawed the other propeller blade down to match the shorter one and it flew reasonably well out of the jungle until it could get properly fixed—no third blade involved. Of course, this cannot be confirmed, nor did it comply with MAF standards of safety, and it was 60 + years ago.

Now all of your responses make more sense to me. Thanks, everyone!

Answer 1

A blade of a propeller breaking off in flight is rare, but not unheard of. It can be catastrophic- the imbalance can tear the engine straight off the airplane, and this can happen very quickly.

Unless the blade separating was due to some acute trauma (i.e. hitting something), it's almost certainly a maintenance issue. Either some unnoticed damage to the propeller was allowed to worsen, or the blade was improperly attached to the hub in the first place.

The repair sounds extremely implausible:

• Propellers take the most abuse of any component on the airplane- centrifugal forces on the base of the blades are in the tens of tons. It seems likely that a field weld would be much weaker than the original propeller and could easily just cause it to separate again in flight.
• Trying to fly with 2 blades instead of 3 would result in dramatically lower available power (without overspeeding the engine, anyway). Light aircraft don't have that much power margin- I find it unlikely that the plane would be flyable even if the weld held.
• While having the blades at 180 degrees from each other would reduce the imbalance, it would still be large if the blade were not attached perfectly.

Answer 2

This is a fine story, but:

When you see real propeller hubs, you'll quickly understand that one does not simply transform a 3 blade into a 2 blade with simple cut and weld methods: (picture source: e-bay, Smokin Rivet Airparts & Salvage LLC)

As you can see, the hub is not solid. cutting one seat off would leave enormous gaps to fill, and while with proper equipment and environment that would be possible, in field it is not. Attaching the blade directly into the "valley" of the hub would be just as problematic.

As pointed out in Sophit's answer the weldability of the hub material and availability of proper equipment is questionable to say the least, and aligning the blade properly will be a chore. Then there's the imbalance caused by the lost blade as per Chris' answer, which will render the plane pretty much unflyable, quite likely by ripping the whole engine off.

As you stated in your comments, you can't prove this story, but it's pretty much debunked here.

Answer 3

Propeller blades are made either of high-strength aluminium alloy, wood or carbon fibre. None of those materials can be welded, except aluminium but only with very specific equipment (using argon as shielding gas and welding rod based on aluminium).

Just remember the story as it was told and don't ask yourself anything else 🙂

Answer 4

This story is not plausible.

The location would have been Shell Mera in Ecuador. The Amazon is large, but Jim Elliot worked in Ecuador. Several different planes have been used out there. The Piper that was used during the fatal flight was a yellow Piper 14 Family Cruiser, which was light. Several other planes have been used since in Ecuador. Amongst others a Cessna 180 and Cessna 206 Turbo. These are relatively powerful piston engined planes. The propeller would spin at about 3000 RPM, but the torque during takeoff would be enormous.

Reasons why this is not plausible:

• The propeller blade that departed the plane would probably wreck the plane by breaking the motor mounts.
• The fracture would not be a clean one, making it extremely difficult to fit another blade to the fracture. As a matter of fact, the fracture would in itself cause an imbalance, unless it is cleanly cut off using a lathe. The Cessna 180 has a constant speed prop. The governor would also not work.
• The blade is a profiled aluminum blade. A weld would only cover the surface, not the core.
• A welder in the cargo of the blade is very unlikely. These are extremely heavy loads, as it also needs to be fuel powered, and unlikely a electric transformer type. You don't just tag one along like a wrench, just in case you need it. If it would need electricity, you would be out of luck after an emergency landing, and if it would burn fuel, it will be a fire hazard. If it was in the cargo load, then it's unlikely that there would be aluminum rods to weld, as everything out there would probably be steel. Aluminum welds are hard, and probably need MIG/TIG including the needed gases.
• (Near) crashes were not uncommon. However, there were always alternatives to get the planes out, for instance with broken gear legs, flat tires, even cylinder failures. The procedure would be easy: call to the base station, describe the needed parts and fly in assistance. Then repair the damage in an authorized way, and fly it out after testing it properly.

I spoke to a retired MAF pilot that was stationed at Shell Mera in Ecuador, and he could probably confirm that this would not have happened. He also wrote a book about his work in Ecuador, and while he told me some wild stories and wrote it all up, it would be hard to explain why he left this story out. There can only be one reason in my mind. It didn't happen.

Can you share more details like the approx date, location and type of plane or even registration?