Vans RV-4 (oz10157)

About this Plan

Vans RV-4. Radio control giant scale model, for Quadra power.

Quote: "RV-4 by Hal deBolt. The two-place version of Van's Aircraft's popular RV-3 homebuilt, in 1/3 scale.

THE RV-4 STORY is ready to be told, but before I explain this giant-scale project, I'd like to list the standards it was based on. Above everything else, I wanted a pretty, exact-scale rendition of the RV-4. The model also had to be aerobatic, simple to assemble and fly, transportable in a compact car, and use a Quadra engine along with any standard R/C system. And finally, I wanted the RV-4 to be a time-saving, low-cost structural design. Carefully following these objectives made the RV-4 all that I hoped for.

What made me decide to build an RV-4? Well, learning that the full-size plane is a two-place sport-aerobatic craft with a wingspan of only 23 feet and a top speed of 202 mph certainly helped. The RV-4 also offers exceptional STOL performance, and can take off and land in the length of a football field. After considering these factors, I thought how fantastic it could be to try a home-built, giant-scale RV-4.

The RV-4's designer is Richard Van-Grunsven. Richard's reputation grew when his prototype RV-3 craft demolished all the efficiency EAA records at Oshkosh a few years ago. The RV-4 is a two-place, larger version of the RV-3 with improved acrobatic and STOL performance. Study the three views and aerodynamics and you'll see what I mean.

The RV-4 is bigger than the average giant scale model. That's because Richard wanted a design with an ample wing area and its aerodynamic benefit. I added a laminar-flow NACA 65015 airfoil to gain wing efficiency. This larger wing requires 1/3 scale. That means a bulky fuselage which produces more drag.

However, Richard considered this problem when he designed the RV-4. His design provides a clean fuselage, even in 1/3 size. The Quadra handles the combination with efficient speed. The minimum power creates no problem in the maneuvers. This wing also helps slow down landings, though there is a floating tendency. But now I'm getting ahead of myself. Let's start with some RV-4 basic features and techniques that enhance the sub-structure.

The RV-4's Quadra engine mount is neat, light, and compact. The Quadra prop extension moves the prop just forward enough so the magneto does not create clearance problems. It also allows a scale cowl shape.

The stock Quadra muffler is also cheap, compact, and light. I added on a VW auto valve-pushrod tube. This large-diameter, thin-walled, steel tube of ample cross section has built-in expansion bellows..."

Vans RV-4, MAN, January 1983.

Direct submission to Outerzone.

Supplementary file notes

Article pages, thanks to RFJ.

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