Javelin (oz6067)

About this Plan

Javelin. Radio control sport model. Javelin of RCM. Scanned from orginal Plans in 300dpi. Type Model Delta Wing. Model # pl-1239. Wingspan 42-5/8 in. For .40 glow engine and 4 channel RC. Designer Bill Winter/John Hunton. Magazine RCModeler RCM 9-97.

Quote: "You know your airplanes, so run these numbers by: a new piped K&B .40: a span of 42-5/8 in, a gross of 4 lb 15 oz, and a wing loading of 17.67 oz/sq ft. Doesn't compute? Yes, it does. For starters, the delta wing provides an area of 644 sq in. The ultra short-coupled canard 'tail' adds another 125 sq in and, since it is set at a positive angle of incidence, it is a lifting surface, unlike conventional stabilizers which normally provide a download for pitch stability. Include the foreplane area, and the loading drops close to 15 oz/sq ft. For less fiery performance, we found a plain bearing 0.5..40 to be quite satisfactory.

Obviously, with the K&B, it goes like a scalded cat, climbs like a monkey, yet it behaves. It is quite stable due to the nature of the delta and stays where you put it. Roll is anything you crave; let up on the stick and rotation stops like a razor slash. Take-offs are short, landings smooth, though a tad faster. It is safe to fly in any maneuver; there are no X-ship quirks. But ask yourself one question before taking the leap. Do I know myself to be a capable pilot? This plane is on the small side, can be quite fast, and covers a lot of ground quickly, perhaps more so than other airplanes in your log book. Of course, its slotted canard/wing arrangement, with a delta's resistance to dropping a tip, and affinity for high angles of attack means that it probably has a greater speed range - high-to-low ratio - than anything that you have owned. So you can always throttle down and come off the pipe.

Important, choice of power plants. The lower range is a plain bearing .40; the top, a ball bearing piped .40. The former provides performance beyond any trainer type .40 airplane. So powered, the Javelin is in the performance category. With the piped .40, the Javelin is for qualified pilots.

It will take off and fly without being on the pipe. Then, if you throttle back a bit, it will come off the pipe (if you need a breather). Incidentally, Javelin will climb vertically on the piped engine, and can do four rolls while doing so - then it comes off the pipe. The instant speed is restored, it goes back on the pipe.

Javelin is not an off-the-top-of-the-head design. It is the third of three progressive, related designs, the first of which was the successful pusher canard QED. The second was a double delta pusher, that is, a 60°/145° single surface. Solid experience with these two craft pointed the way to the
ultimate of the trio: the Javelin.

A few points of interest: The Javelin is a 4-channel aircraft and has elevators on the foreplane, elevons on the mainplane, rudder/steering, and throttle. That is a lot for your money. Those having more exotic radios can replace the sliding servo tray with two servos for the elevons and, thus, take advantage of various mixing and movements. Be sure not to exceed the specified control surface movements - notably on aileron - and don't second-guess the CG position. All servos are in the fuselage as well as a mechanical mixer tray to drive the elevons, and by an auxiliary short pushrod, the foreplane elevators.

The delta wing is special. Its geometry, with bottom surface rising to tips, provides effective dihedral. Seen from the back, the dihedral is visible along the trailing edge. The trailing edge rises from the centerline, which also governs the incidence angle of each rib section.

The blending of a canard configuration with a full delta alters the aero-genetic code. It allows delta good stuff, with modified delta traits to allow normal landings, and so on. This is a well-tested machine. It is a small airplane with big performance. Just fly it like anything else - but with respect..."

Update 26/03/2016: Construction article added, thanks to Koranron

Supplementary file notes

Construction article, 12 pages.

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