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High Flight Articles

Volume IX No. 2 Page 50 1988



CURTISS GULFHAWK
Review by Chuck Spencer IMAA 821

v9-2-50.jpg - 4.5 K

This is the first of two plan reviews for this month, both done by Dick Barron. They are excellent plans, as are all of his plan sets. It should be noted that as of this writing, Betty Barron is continuing to offer the plans that her late husband Richard Barron offered for many years.

The first is of a Curtiss Gulfhawk, with six sheets.

Sheet No. One:

The first sheet has a side view of the "Gulfhawk" and it's length from prop hub to rudder trailing edge is 66 and 3/4 inches, and it stands 28 inches high. The fuselage side-view shows the sheet sides with former locations and fin and rudder construction, which is built up of balsa on the fin, and the rudder is a sheet core with split ribs on each side of the core. The core is 1/8 sheet. All fittings for empennage brace wires are shown, and construction of the tailwheel assembly is shown. Cabane struts mounting are shown and are from 5/32 wire, with balsa fairings.

Landing gear mounting is shown along with shoek-strut adjustment. The cowling is shown with a notation that a Kioritz engine is recommended. Wind shield pattern is given. Color patterns are also shown along with the color scheme. Rudder and elevator control horn shapes are also shown.

Sheet No. Two:

The fuselage top view with stab end elevator construction, and the shape of the sheet side of the fuselage. The basic fuselage is box construction with formers and stringers added. Cowl rnounting brackets are also shown. Stab and elevator construction is the same as fin and rudder construction, except that there is no center core. I get the impression that due to the short nose movement, the empennage should be kept as light possible.

Sheet No. Three:

This is a front view of the "Gulfhawk", and also a 3/4 rear view of the partially completed fuselage and empennage, with landing gear and cabanes attached. Flying wire and fittings are also shown. And since this airplane has ailerons in the top wing only, with operating struts to the bottom wing, this also is shown very detailed. Layout of landing gear construction is shown. The gear struts are built from 7/32 and 1/4 inch wire, and construction of the shock system is detailed. I have found that if you will contact a Small Implement Dealer, he will more than likely save you the broken coiled spring steel re-wind springs used in lawn mowers, snow throwers and such. Most of these are around eight feet long and 3/16 inch wide and are the closest thing to a streamlined flying rod, I have found. They can be drilled in a drill press and end fittings can be soldered to them. I have used them and have not had one break yet. The bluing I remove with crocus cloth and steel wool.

Sheet No. Four:

This sheet shows all former layouts with notches for stringers, plus mechanism for stab incidence adjustment. Stab incidence is shown ground adjustable, but could be made servo operated so you could adjust it in flight.

Iterplane struts construction is shown and it is constructed from K/S streamlined tubing. Fittings for attachment are also shown and I would modify clevis attachment to the tubing. I would bend to a "Z" shape so it wedged in the tubing then I would cover the end with Hobby Poxy

Sheet No. Five:

This plan sheet shows the top wing construction. It is beautiful. There is NO dihedral and there is lots of ribs, approximately 2 inches apart, and everyone a different length, even in the center section. When viewed from the front, the ribs get thinner towards the tips, creating an illusion of dihedral. Spars of which there are two from 1/8 inch ply and the leading edge is 3/8 inch square balsa. Airfoil is Clark Y and trailing edge is 1 1/4 inch by 3/16 inch balsa scalloped between each rib to look like wire.

Why not use 1/16 inch aluminum tubing and bend it slightly between each rib to create the same effect. Ailerons are from 16 inch base plate cut to aileron shape with zigzag balsa ribs and half by half balsa leading edge. Flying and landing wire attachment bracket patterns are shown. Also top wing attachment to cabanes is shown.

Sheet No. Six:

This plan sheet shows bottom wing construction and it is basically the same as the top wing, however there is 2 1/4 inches of dihedral under each tip. Aileron double bell crank construction is shown, and aluminum interplane strut attachment plate patterns are shown. Both the top and bottom wing are sheeted back to the front spars with 1/8 inch balsa.

Just by going over the plan I would guess the weight between 25 to 30 pounds, the approximate wing area is 2076.75, giving a wing loading of 33 ounces per square foot at 30 lbs. In summarizing the plans, I was very impressed and think it would build into a great looking real airplane. (Two wings and a round engine) and should emit a good feeling of accomplishment both in building and flying.


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