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Martin Torpedo Bomber

Martin T4 Torpedo Bomber


Most of the articles on this website show finished works. We thought it would be interesting to show a work-in-progress.  Joe Weathers builds models out of balsa wood and showed us the really clever way he built the folding wing on a stick-and-tissue Martin T4 Torpedo Bomber


The T4 was in service between 1921 and 1928. It was not a dive bomber because it would never be able to pull up without shearing its wings off.


torpedo bomber


We should point out that this is not a kit – it is scratch built from plans. Anyways, the problem Joe faced was how to get the wings to fold back so they were parallel to the fuselage. The Navy had to stow 28 each of them aboard the carriers Lexington and Saratoga. Folding the wings allowed them to traverse between the flight deck and the hangar below.  Keep in mind that the T4 was a biplane.


torpedo bomber wing


On the model, a rear section of the wing alongside the fuselage was removed so the wing could rotate backwards. The void created a space so it could pivot, which is how it was done on the real airplane. (The Fairey Swordfish did it the same way, except that the T4 did it 5 years earlier.)


The pivot point was located on the rear spar. The model accomplished this by inserting a Robart conical shaped hinge that tapered into a piece of 1/8 inch square aluminum tubing. To spread the load, the tubing spans four ribs.


torpedo bomber hinge


One last item is how the front part of the wing separated. A pin was driven into the leading edge, quite similar to the way the hinge pin on a regular door operates.

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