Gary Boldt's Comments on the Old Four Monoplane Design
1.     This is a neat old design but I'm not sure whether we can believe the claims of flight performance mentioned in the article.
2.    No dihedral is given or shown in the plans.
3.    The rubber motors pass over the wings. This will probably result in the top wing surfaces being destroyed in short order. For this reason, and also given orientation of the wire cross stays on the basic structure, it would be better if the motors ran down the sides of the motor bases rather than the top. There should be adequate propeller clearance but if not, the rear landing gear brace could be lengthened a bit.
4.    Parts F and J are specified as 11 and 13 inches long respectively, the full-scale drawings indicate they should be longer. I would suggest using a generous length and cutting to size after attaching the vertical braces and wheel axles.
5.    The original plans also suggested modeling the plane with floats and/or additional wings to form a tandem biplane. The float structure looks like a rather poor design and better can be obtained from other sources on the Internet or various books.
6.    The design would benefit from some material substitutions e.g. balsa and tissue, etc.
7.    This model is somewhat reminiscent of the Langley tandem and might offer a platform for some experimentation in terms of relocating the propellers between the wings and adding a tail structure like the aerodrome.

dannysoar's Notes & Comments.
1)   First I'd like to thank Gary for the excellent work . The copies he sent me are works of art and my GIFs are sorry copies.- It's an excellent argument for the CAD vector files.

2)  It came from a 1927 Popular Science book, so it could be a reprint and older than 1927. It looks it.

3) It's always an issue with these very old models. There are always a number of obvious possible improvements. But if you make them you are sacrificing character and authenticity for flyability. I've made to such airplanes. One was a Hittle Tractor as original as I could make it. I never dared fly it. The other was the 1912 Butler  I replaced the oiled silk, rattan and spruce with balsa and tissue , but kept the outlines. It flies a nice two minutes.   But the Butler is a much simpler airplane. Maybe not as fun as an Old4.

4) Gary suggest running the motors along the side of the motorsticks. I would be tempted to raise the front motor hooks.

dannysoar5