Could anyone help with this prop

[pmdec]

Hi,

Ok, very fine pics. Has anybody ever saw "AID TRY" stamp yet?

For measuring the pitch, it is very simple:
- put the prop on the same table as your pics, with the flat side of the blades up (the contrary of the pic #7230),
- measure one meter from the center of the central hole and made a mark at this place,
- open the clinometer application on your iPhone (open "measures" then choose "angle" or similar (I have not the notice in English)),
- lay the phone on its side on the hub perpendicularly to the prop blades axle, and verify it shows 0 degree,
- lay the phone on its side at one meter of the center of the central hole perpendicularly to the blade axle (that is, measure the "slope" of the blade at this point) and give us the angle.

Regards,
PM

[David Bathe]

Thanks:
I think the stamp you're referring to could actually say: AID 72V which is the same as the other stamp on the opposite blade.
The Central Hub appears to have a similar stamp with AID 21S (or 125 or 12
By the way, I don't question the pitch, it's stamped into the hub as was the diameter.
That turned out to be 100% accurate and my drawings are showing it's a standard propeller... with 3.5 cm added to each tip and sanded out.

[pmdec]

Hi,

About the stamp, I am not sure about what is the right reading from the pic.

image_10587_trnd&txt.jpg

About the pitch, why dont't you give the angle? It would just be a confirmation.

What did you mean with "3.5 cm added to each tip and sanded out"? Could we have a close-up of a tip (~10 cm)?

Regards,
PM

[David Bathe]

The problem is, now I've finished the pictures/ measurements for my drawing, I've put the prop back into storage and don't want the trouble of going and getting it out again LOL.

Regarding the production marks:
Well it's definitely not TRY as the other picture showing the opposite blade looks clearly like it's marked with a "V" and not a "Y."
The Mark on the hub says either: A.I.D 218 or 21s. Seeing the other marks ended with a "V" I guess its a "s" and not a "8"
A nice find was the black ring that runs around the coloured centre section of the hub. Measured the diameter at 190mm.
When I check the hub data on the pdf down loaded from this site it says a diameter of 7.48" convert that to metric and it's 189.992mm!
I love it when that happens PM... it's mechanical archaeology!

[pmdec]

Hi,

I have a standard (2590mm) AD 644 which is later than yours (G1207) and it is stamped for Sopwith F1. It has also a circumference mark but I am not sure it is from the metallic hub plate. Anyway, I will measure it ... although the prop is in storage ()! Give me one or two days because my storage is 20 km from home. Perhaps this will give you some time to "visit" your prop and measure the blade angle?

IMGP8422&8428_cr_ac_sh_900pxH.jpg3Vues&Marquages_Qual6.jpg

[David Bathe]

Save yourself a trip, it'll be 190mm
Nice prop.

[pmdec]

.../..., it'll be 190mm.../...

Nope... 200mm on front side and 198 on rear side!

IMGP8640_front_800px.jpgIMGP8640_cr_arr_800px.jpgIMGP8641_rear_900px.jpgIMGP8641_cr_arr_800px.jpg

Regards,
PM

PS: Your three last pics are too small to be readable...

[David Bathe]

I see that...I don't understand why, I'm uploading big screen shots.
trying again.

did you check that against the hub dimension pdf?
Screenshot 2022-11-19 at 16.34.42.pngScreenshot 2022-11-18 at 22.58.38.pngIMG_7239.jpeg

[David Bathe]

No idea what's going on, all files the same size. Your prop against the technical drawing is wonderful.
Send me your email instead.

[pmdec]

Hi,

Yes, I already have the measures of your PDF and all measurements are the same except the size of bolts (70mm central hole, 150 mm bolt holes circle, ... , but 11 or 12 mm bolt holes (I have to verify and it will be for another day...).

I think YOUR circle marks are from the metallic hub plates, but MINE are from drawing during prop repair (the fact that one marking is embossed is from sanding and washing before repairing). It is a repair from WW1 and the prop was not re-used (no round witness marks).

For the mail, I send a message.
Regards,
PM

[pmdec]

Hi,

Looking at Bob's book about English props part one page 20, you can see he has listed seven occurrences for AD 644. All with a 2650 mm pitch when it is written (for two there is no diameter nor pitch written). For three of the five remaining, the written diameter is the "classical" 2590 mm but for two it is 2500 and it seems not known for two.




So, 2500 could be a miswriting in the docs viewed by Bob, or a miswriting by himself. But it could be also than two diameters have existed for this drawing.

And if two, why not three?

Just a possibility… And you can remark that the two precedent drawings (AD 642 and 643, a pair of RH/LH) were 2660 long. The only other AD drawings with this length are 671 and 672 (also a pair of RH/LH).

Regards,
PM

[pmdec]

Hi,

Looking at Bob's book about English props part one page 20, you can see he has listed seven occurrences for AD 644. All with a 2650 mm pitch when it is written (for two there is no diameter nor pitch written). For three of the five remaining, the written diameter is the "classical" 2590 mm but for two it is 2500 and it seems not known for two.

IMGP8654_rot_cr_ac_sh_800px.jpg

So, 2500 could be a miswriting in the docs viewed by Bob, or a miswriting by himself. But it could be also than two diameters have existed for this drawing.

And if two, why not three?

Just a possibility… And you can remark that the two precedent drawings (AD 642 and 643, a pair of RH/LH) were 2660 long. The only other AD drawings with this length are 671 and 672 (also a pair of RH/LH).

Regards,
PM