Saturday, May 16, 2015

Special Hobby AF Question

A question was raised about the length of the cowling based on a photograph of a Grumman AF model built from the recently released Special Hobby 1/48th kit, specifically whether it looked a little short. (

Based on a pretty good Grumman three-view, which compared quite well to the Grumman fuselage station data, I calculated that the distance between the leading edge of the wing at the fuselage and the forward edge of the cowling at the fuselage reference line (where the propeller shaft extends), should be 69 mm or about 2 3/4 inches. The kit dimension was subsequently reported to be 65-66 mm.

At that point, I double checked my scaling of the fuselage station drawing (good only for length, not shape, particularly the vertical fin in this instance) and the Grumman three-view and added the AF Standard Aircraft Characteristics side view for comparison. All the drawings compared well in length, with the clear exception being that the wing on the SAC side view was about 3 mm farther forward than on the other two drawings.

I cropped the above to illustrate the difference between the SAC wing location and that of the other two drawings.
It's possible that Special Hobby relied on the SAC sideview for the wing location.

The perceived discrepancy in the picture of the model is likely exaggerated by the camera.