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Motorace
11-27-2017, 03:32 AM
I acquired a large radio-controlled flying model of a De Havilland DH4 US Mail plane that did not come with an engine or propeller. I plan to just hang it from the ceiling of my garage as a static display, but I've not been able to find any specifications on what diameter the original 2-bladed prop was. Some of them might have had 4-bladed props, but I plan to do the Liberty-V12 engined US Mail plane version with a 2-bladed prop. Can someone here please provide me with the correct diameter?

Thanking you in advance -

Bob Gardner
11-27-2017, 08:29 AM
Hello Motorace,

Welcome to our forum.

The British experimented with a Liberty engine in both the DH4 and the DH9. The prop had the drawing number T9669 (which was a drawing number from the Royal Aircraft Factory indicating they did the experimental work of putting a Liberty 12 into a DH4 airframe). There is also a second British drawing number, USA22699.

These props were all two bladed with a diameter of 3050mm and a pitch of 2250mm for a Liberty 12 of 400hp.

Thank you for these lovely photographs. Is this your large rc model in the two right hand photographs? Is the aircraft on the left airworthy? I didn't know there was a DH4 flying in the States. It looks superb in US Mail colours.

With kind regards,

Bob

msprior01
11-27-2017, 09:26 AM
HI Motorace,
Here is a pic of my daughter with our DH-4 propeller. It has a bit of tip strike damage, but would measure out at 9' 6". It is engraved " LIBERTY 12". It was manufactured by Sonninger of CT and dates to WWI.
It is for sale if anyone is interested.
Thanks, Scott

Dbahnson
11-27-2017, 09:41 AM
Here's another one (http://www.woodenpropeller.com/DH4Eagle.html) that I sold a few years ago. The side view might help you make a a realistically proportioned model. I think I might even have a drawing (blueprint) of one at home. Let me know if you want me to look for it.

http://woodenpropeller.com/forumvB/attachment.php?attachmentid=6907&stc=1&d=1511790205










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Motorace
11-28-2017, 06:04 AM
Dear Bob, Scott, and Dave,

Thank you all for replying so promptly and thoroughly.

Bob, There is indeed a restored flying example of a Dh-4 M2 mail plane in the USA. It was restored by Peck Aeroplane Restoration (http://www.peckaeroplanerestoration.com/) and flew at Oshkosh in 2007 (http://fairchild24.com/dh4.htm).

There are a ton of detailed photos of it undergoing restoration here (http://www.peckaeroplanerestoration.com/projects/dh-4-mail-plane/).

Scott, thanks for posting your photos and dimensions as they show a different style than Dave's

Dave, Thank you for offering to pursue the blueprint, but this is for a man-cave display... I'm not that concerned with getting the propeller exact beyond the correct diameter (plus I may darken it). If I can find one with an older style scimitar shape, I'll use that, but beyond that, I think my friends will not notice the difference.

The guy who built the model plane did a beautiful job, but then lost interest because it flew too slowly for his interests. My garage won't get completed until next spring, but I'll post some photos when I've got it on display.

Thank you all again!
- Dan