Engineering Division GL- series (1920s aerial target gliders)

[Jos Heyman]

I picked the enclosed picture up from http://www.edwards.af.mil/photos/mediagallery.asp?galleryID=530&?id=-1&page=1&count=48.
It shows the G-3 aerial target glider that, as I can determine, was tested in the late 1920s or early 1930s.
The target was to be used for aerial gunnery training in which a pilot carried his target glider aloft. After release, the glider took several minutes to reach the ground. During this time, the pilot could make several gunnery passes against it. Tests were performed with Curtiss XA-4 27-244 also XP-500.

The factsheet at http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=7663 states that the McCook Field Engineering Section developed a series of target gliders in the 1920s, including the G-3. In December 1922 J.A. Roche designed the first model, the GL-1, as a target for anti-aircraft gunners of the U.S. Army Coast Artillery. These early targets were the first and only gliders (manned or unmanned) used by the U.S. Army Air Service.

From my own data: The GL-1 was an unmanned target glider built by the Engineering Division and had serial 23-001 (in a sepaarte series for gliders) whilst the GL-2 (which carried serial 23-002) was a manned glider.

Can anybody provide some more details of this series of gliders? I would love to know if here were any designs beyond G-4 and how many G-3 were built an tested. What time frame were the tests performed? What serials (if any) did the G-3s carry?

I know, this is all specialist stuff, but some of you guys have incredible archives....

 

[Apophenia]

Jos: a little bit more on the GL-1 and GL-2. I'm puzzled by the "G-3" designation.

An image of the GL-1 accompanies "Small Glider Target for Anti-Aircraft Guns", Popular Science Aug 1923, pg 35. The GL-1 is shown on a similar above-wing mounting (but on a DH-4). McCook Field's GL-1 is described as "made of linen, wood, and a piece of metal [the fuselage's 2D tubular structure], has a twelve-foot wing spread." Setting horizontal tail and rudder determined flight path. Descent from 10,000 ft took about half an hour. Other than being mid-winged, the GL-1 looks very much like the later G-3.

J.A. Roche's GL-2 was another high-winged design (recycling the upper wing panels of a JN-4). Jean Roche (longtime liaison between the Air Force and NACA, Langley) went on to develop the GL-2 design into Aeronca's powered C-1 (albeit now with Clark Y airfoil). So, it's not a huge stretch to relate the GL-2 to Aeronca's later TG-5 training glider.

Popular Science Feb 1926, pp 11/12 also discusses aerial targets, showing both towed targets and an air-launched glider. And that brings up the designation puzzle.

All refs mention "G-3" and that's how the restored aircraft is marked. This photo shows 'GL-3' on the fuselage side (along with a large roundel/bulls-eye). Note too that "GL-3" has a fully-covered (fabric?) nose.

 

[Apophenia]

I forgot the image of the GL-2. Photo is from the National Soaring Museum, reproduced in J.N. Grim's "To Fly the Gentle Giants: The Training of U.S. WW II Glider Pilots", AuthorHouse, 2009, ISBN-13: 9781438904849 ISBN-10: 1438904843

 

[Jos Heyman]

This seems to confirm to me that the G-3 designation is most likely some invention of whoever wrote the USAF Museum factsheet and 'interpreted' it as G-3. I think I am going to stick with GL-3.