Help identify please!!!!

[Mike]

Hello everyone! What a great forum! I've got several very old propellers I've been able to identify and fix and some neat things from my family I've collected over the years but these are giving me trouble.

These are a barn find of my family's and they were absolutely unidentifiable under the mud and dust from the 70 or so years that we've supposedly had them through a documented story of the family.

It is a six bolt pattern, lighter wood(maybe from the age and clean up), four panels. They are matching in paint but the paint is better on one and completely flaking from the other. Here are the remaining specs that I can find and serial numbers I could get off. There are some covered in the paint but I can't make them out and one prop has brass? edging I think and a lead plate that has no more distinguishable marks.

Length - 10 ft
Width - 85mm
Six bolt pattern with 170 or 171mm between the centers of them diagonally
Hub diameter is 60mm
Width at widest part of blade is 8.5inches
Single lead plate is 48mm x 33mm and held in place with four standard screws
See attached pictures for numbers and design
Plate thickness is 7mm and 9inches in diameter
Bolts for the plate are 116mm long and 9mm diameter at thread

The blade that has the deteriorated paint I would like to clean off and redo and polish the brass but the painted one I would leave and give to my brother, or should I simply leave both as is? I don't know if the original wood was the norm and it got painted later and displayed in the farm house some long time ago. My Great Uncle who had these was one of a few that went Jenny's to Jets in his career, kept a daily journal (which I am having trouble finding these in)and has lots of awesome aviation related things. My concern would be the drying out of the wood overtime leading to more cracking. These are old and were in a barn in Illinois for the majority of their life and I have them now in Arizona. Any help and guidance on how to go about saving them would be greatly appreciated too

[Dbahnson]

That's going to be very difficult. All I can see is what looks like serial numbers, which don't help identify them at all. Maybe you can make out any numbers and letters that are stamped on the hub?

[Mike]

I would need to try and chip away the paint on the hub, there is some old grease and several layers of the paint. Would that matter too much? Any ideas of how to go about it? There is what appears to be a 1 and then blank under the paint and a 3. Maybe four digits by the spacing? That's on the well painted hub. It might be a T and then some spacing with a 3.

To help kind of date these, the family story that I'm still trying to find written but we do have old pictures of it, was an old twin bomber was on its way to the boneyard and my uncle was flying it, stopped at the farm and got the bomber stuck in the mud on the landing patch. From my memory it was an old twin Jenny going to the bone yard. These and several other heavy items were removed and stored at the farm so the airplane was able to get off the ground when departing. From the family hand down pictures and stories it sounds like it happened in the 30's. I'll do some more digging to see if I can get pics and post them too.

[pmdec]

With a diameter larger than 3 meters (10 feet),
- only 6 bolts, and thin ones (9mm),
- small central hole (60 mm),
- no airworthy stamp visible,
it is not from an aircraft. Perhaps a wind generator or for a water pump...

Sorry to be the bad news provider...
PM

[Dbahnson]

I was thinking wind machine as well, perhaps stacked together as a four blade.

These tales that go with artifacts are rarely valid. There was no twin Jenny, and they certainly don't appear to be military.

[Mike]

Yeah I had a feeling something was weird about these two since they were supposedly tossed out of the aircraft to lose some weight. I'll do some more digging through my family stuff. Thanks for the help!

[Mike]

There was an experimental twin Curtiss in the 20's used when the military was experimenting with night time bombing. But no clue to the amount made or anything like that.

[Dbahnson]

Those are also left hand propellers, which pretty much eliminates any kind of Jenny variation.

[Mike]

i was just noticing that too. thanks again.

[Mike]

I heard back from the National Air and Space museum curator and he couldn't track the whole numbers and identification of the propeller but with the lead plate and balancing pieces, repair mark on one and the brass plate covers and the nail scratching of "Eng Side" he said he was very sure that these were used as propellers but redirected me back to this web page because of not having the resources to go through their archives.

I found another marking but it is hard to make out. It is a circular stamp and says USP or USA(it's slightly damaged) and below it looks like three numbers but I can only make out what I think is an 8. I've attached a rubbing of the numbers and stamp as they are together on the prop. Any idea where I might start doing some research on left hand pitch props? Still curious to do some more digging on these.

[pmdec]

Hi,
I was just asked by mail to give my advice.
I just can confirm my first one: IMHO, it is not an aircraft propeller. And probably not a propeller in its strict sense.
Perhaps blades for wind machine. Perhaps an autogyro rotor if you "need" it is from an aircraft, but it can't be a propeller from diameter and bolts size and number (IMHO !)
Regards,
PM

[Wincharger Mike]

I would agree that they may be wind electric. There were a couple of wind electric plant manufactures in the 1920s that had props very similar to aircraft props. HEBCO of Elkhart Indiana used 4 ply walnut and made 10 and 12ft props. However, all of the HEBCO props I've seen (3) had hubs with 8 bolts. They could also be a prop to a Perkins wind electric, another Indiana company. I've never seen one of those other in literature. The literature does say they were 10'. I collect the old wind electric machines so if you ever decide to sell one, I may be interested.

[Dbahnson]

Any idea where I might start doing some research on left hand pitch props? Still curious to do some more digging on these.

The challenging problem is that there were thousands of different wooden propeller designs that had been used in the first 40 or 50 years of aviation. Some were high production items, some were homemade, and some were clearly labeled with identifying information and some were not. The problem attached to that is that there are poor records at best that could be used to trace numbers back to the actual or intended use for the propeller.

So even with clear stampings it's often hard to determine what the prop was for. The left hand thread isn't unusual, but isn't particularly helpful either, as it just eliminates some of the more common applications but doesn't point to any specific one.