Curtiss XP-55 (oz14303)

About this Plan

Curtiss XP-55. Profile scale model for control line. For .049 - .051 engines. Scale is 1/24.

Quote: "Profile Curtiss XP-55, by Jim Wilson. Exciting and unusual semi-scale profile control liner for beginner and experienced alike! Our pusher Ascender has wild and rakish lines but still flies with the best of them.

One of the most unusual planes ever produced is the XP-55 Ascender. There are others, but none has the wild and rakish lines of the Curtiss. It's one of those planes that looks as if it is going 300 mph before it even starts to taxi.

A couple of years ago, some members of the St. Louis area scale club were discussing the possibilities of modeling some of the more unorthodox designs for U-control scale. The Ascender was brought up immediately - everyone seems to like this one. A careful look at our libraries showed some good three-views, but nothing on cockpit details and other points that are needed for contest flying. Several letters failed to turn up anything on this.

Curiosity being aroused, we decided to build a profile replica just to see what would happen. The 1/2A size was chosen for economy, and to reduce building time. The three-view appearing in 'Air Force Fighters 1916-1961' was followed as closely as possible. Aside from the profile fuselage, the only deviation is an enlarged front plane.

Before going on about the model, here's a little background on the full-sized version. About the middle of WWII, contracts were awarded for several aircraft that were new and different in one way or another. Jets, all wood fighters, flying wings, pod and boom designs and canards were tried.

The XP-55 was a single place fighter with a span of 40 ft, 7 in and a length of 29 ft, 7 in. It was powered by a 1275 hp Allison V-1710 engine. Top speed was 390 mph with a jettisonable propeller permitting the pilot to bail out safely.

Although the performance of the aircraft was good, a crash on the proving runs caused the project to be dropped. It was felt that the design was a promising one; however before changes could be applied, the war came to an end, the jet plane came on the scene, and an economy cut back was ordered. So ended the XP-55.

Ever hear that one about how anything will fly on lines? It might be near the truth - but only near.

Two profile swept wing canards were built in the St Louis area. One was a large Japanese Shinden, built by Mr Jim Langford, and the other was the author's first XP-55. Both had lifting airfoils. Well, the Shinden wouldn't take off. The faster it went, the tighter it hugged the ground. All that lift that far aft of the CG pinned the nose down but good. The author's XP-55 would take off - do half of an outside loop and crash.

Both planes were modified to incorporate symmetrical airfoils and larger front planes. Now both would fly. Nose weight takes out the sensitivity; so follow the plans closely on this!

Construction is so simple that only the high points will be covered. When building the fuselage, cut the nose weight hole out, and add the nose gear wire before going any further. Lay the fuselage on its side with a piece of 3/16 or 1/4 balsa under the weight hole. Fill the hole with lead. When cool, the weight can be filed smooth. Add the engine mount blocks and firewall. The wing can then be built and added to the fuselage. It's best to use Epoxy on all glue joints. The extra strength is worth the extra effort. Add the rudders and the front plane. Slide it back into place, and fill in front of notch with balsa.

Finish in your favorite manner, following the color scheme outlined on the plans. The bellcrank, elevator horn and pushrod should be added after finishing.

Our model was designed for the Cox QZ (Quiet Zone) Engine; but a Golden Bee or Babe Bee will work fine. The engine should be altered by removing the four back plate screws and the back plate. The fuel line is then rerouted toward the outside of the circle. Replace the fuel line if the old one has hardened. When replacing the back plate, rotate it so that the cylinder will point to the outside of the circle with the needle valve up - as shown on the drawing.

We used a 6-4 Tornado-nylon pusher prop. Mount it with the flat side facing the rear of the plane, and run the engine in the usual direction.

Flying: Use dacron lines about 25 ft long or .010 diameter steel lines 30 ft long. UP IS DOWN AND DOWN IS UP! Remember this when you hook up and check out your controls. In other words, when the trailing edge of the front plane is moved downward, the ship will climb - raising the trailing edge causes a dive.

You'll find that the Ascender will attract a lot of attention wherever you take it."

Direct submission to Outerzone.

Update 7/1/2023: Replaced this plan with a clearer version, thanks to MarkD.

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