Unknown aircraft.

[Sock]

Hi everybody.  It's been awhile, but with school and work... Well, you know.  

I'm taking an aviation class at a vocational school this year.  I recently got a research project to do, and I'm a little stumped.  A woman gave my teacher some pictures of three old, early 20's aircraft, that he could not identify.  And our project is to find out as much as we can on them.

The woman who gave them to us says her grandfather took them and that she thought he worked for Grumman.  I went to Northrop Grumman's website and couldn't find anything from the 1920's.

Just looking at the pictures, they are strange.  They have no, or very few identifing marks, and on all of them they have no flying wires, but really think wooden struts.  Though they look like different types of aircraft.  One looks like a De Havilland DH4B, another like a Curtiss Falcon, and the other like a shorter Curtiss JN-4.

My class got asigned one, and the other classes the other two.  The one we got resembles a De Havilland DH-4B, but its a tandom two seater with twin-mounted Lewis guns in the back, and sports a Liberty engine.  Instead of flying wires, it has three sets of very thick struts.  It has almost no identifing marks, except for two (not three) vertical strips on the vertical stabilizer, and the old star and red dot insignia of the Army Air Corps on the wings.  But it has no registration number and no where on it does it says "US Army".  

Is there a web site were I can look up this kind of stuff?  Find out about old experimental aircraft?

Thanks for any help.

[ChuckMajik]

I actually think it is a de Havilland DH-4.
I found some info saying the US rebuilt/redesigned a fair bit of them.

http://www.nasm.si.edu/research/aero/ai ... ll_dh4.htm

http://www.centennialofflight.gov/essay ... 4/DI74.htm

[Sock]

Thanks Steve!  It has got to be a DH-4, or at least a modified version.  Their are only a couple of differences.  Just in the struts, the landing struts (there are three, not two.) and the tail resembles a Stampe.  I think it may have been a one-off aircraft.  Mabye a test aircraft for planned modifications to the DH-4, but it looks like some of them would create more drag.  I have copies of the pictures in front of me.  If I had a scanner I'd show you.

[Hagar]

Hi Sock & Steve. Your mention of no flying wires put me off as most biplanes have bracing wires of some sort. It's possible they don't show up clearly in your photo. When you say 3 sets of struts does this include the centre-section (cabane) struts? It would be nice to see that photo if at all possible.

It could be the DH-4B which was the US equivalent of the DH-9.

The Americans never made the DH-9, but modified the DH-4 themselves to the DH-4B, which was very similar to the DH-9 in swapping the front seat and fuel tank around.

http://www.raf-waddington.com/specials/museum/dh9/dh9.htm

Not a very good photo but this is the USAF Museum example.

http://www.wpafb.af.mil/museum/early_years/ey8a.htm

[C]

Have a look at this page, it has pics of most USAAC aeroplanes of the '20s...

http://1000aircraftphotos.com/USMilitary-USAAC.htm

Cheers

Charlie

[Sock]

Hi Hagar and Charlie.

Hagar, yes that includes the center struts.  And looking closely at the copies I have, their are some wires I can see, but not as many as the one in the photos you and Steve put up.  I was reading today about the stuff the US did to the DH-4, switching the fuel tanks around and all that.  The fuel tanks and front seat weren't switched on this aircraft.  The front cockpit is under the wings, like in the British version.  I'm trying to get the pictures scanned at school and put on a floppy, but I don't know.  Yesterday they said it wasn't hooked up, and I don't think they intend to do so...

And Steve, thanks for the link.  I didn't find the plane, but it was very interesting.  I have never seen a lot of those planes.  I just wish they gave a little info on them.

[Hagar]

Hi Sock. I find this both fascinating & frustrating. I still can't quite picture the strut arrangement from your description. You say the struts are much thicker than the originals. Does this mean they look something like the struts on the Beech Staggerwing? It's possible that the lady's grandfather who took the photos was associated with a company modifying all 3 types of aircraft. A lot of experiments were going on at the time.

on all of them they have no flying wires

You seem to know what you're talking about but I'm assuming you mean bracing wires. Flying wires support the wing while it's airborne & landing wires support it on the ground. On a conventional wire-braced wing both types would usually be fitted in pairs (attached to the outboard ends of front & rear spars) to enable the dihedral & angle of incidence to be adjusted accurately. This is known as rigging which is a very skilled procedure. On a 2-bay wing like the DH-4 it would be even more complicated.