Cloudhopper (oz16029)

About this Plan

Cloudhopper. Radio control sport model. Wingspan 85 in.

Quote: "Cloudhopper. Giant semi-scale Heath Midwing homebuilt 1930s. 85 in span. For .75 to 1.08 2-stroke or .90 to 1.20 4-stroke. Designed & drawn by Brad Shepherd."

Direct submission to Outerzone.

Update 18/5/2025: Added article, thanks to theshadow.

Quote: "At 30% larger than the author's semiscale Pea Patch, this big RC bird flies with impressive scale realism on a SuperTigre .90 and a 16 x 4-1/2 propeller. Cloudhopper, by Brad Shepherd.

I SURPRISED myself with this design. Since I work in a rather small shop with only a 3 x 4 drafting table and have limited retirement finances, I had never contemplated building anything larger than a .60-powered model - until the 1989 flying season.

I flew my quarter-scale Keleher Lark (published in the July 1989 Model Aviation) at big bird fly-ins that year, and took along my semiscale Pea Patch, a .40 FS-powered Heath midwing featured in the September 1990 MA, to fly before and alter the scheduled big bird activity.

When there's a flurry of remarks about our own flying model, somehow even those of us whose hearing isn't what it used to be manage to catch every word. Most of the comments about Pea Patch went something like this: It's a nice airplane and flies great. Now if it were only twice as big.

Maybe they had something there. After talking it over with fellow modeler, I decided that a 30% enlargement would meet IMAA requirements and adapt the model for big bird fly-ins.

The larger version. called Cloudhopper, is all I could have hoped for. Equipped with a SuperTigre .90 swinging a Rev-Up 16 x 4-1/2 propeller, this model moves through the air at a scale-like speed reminiscent of the Golden Age home-builts that inspired it.

Once a few weeks of bad weather and turbulence had cleared, I test flew the airplane on a March afternoon at the Georgetown Modelers' new field in Georgetown, Texas. I bolted on the wing, filled the rank, and fired up the SuperTigrc .90. I taxied Cloudhopper down the runway, turned her into the wind, and pushed open the throttle. After about 30 feet the plane rotated off the strip.

I fed in some slight trim changes, then made a few passes and turns. Everything looked good, but I needed more control throw on all surfaces. I gave the model some down trim at full throttle, throttled the engine back for landing approach, and put in up trim to elevate the nose a bit. The 18 oz wing loading keeps the sink rate and speed slow and easy, making the airplane a pleasure to land, When the winds began gusting across the strip, it was time to call it a day.

Back in my Victoria, Texas home workshop, I replaced the elevator and rudder servo arms with longer ones for additional throw, and moved the aileron links one hole up on the ailerons. These modifications proved effective. On its next flight, oil Steen Strip, the airplane cut through strong gusts efficiently.

Fitted with the indicated power/prop combination. Cloudhopper does aerobatics appropriate to its heritage - and does them with scale realism. Don't expect the sort of Unlimited Acrobatics you'd wring out of an Extra 230 on, say, an Al Willaert A&M Sachs-Dolmar engine.

Construction: Building this model is simple and straightforward. Typical stick-and-rag techniques produce a structure that combines lightness with strength.

I used a high-quality cowl from Steve and Kim Durecki at T&D Fiberglass. The aluminum flange on the windshield is Coverite 1/8 in graphic stripes painted with Sig aluminum dope. The old-timer in the cockpit is a Williams Bros three-inch sportsman pilot. His goggles were pilfered from a Williams Bros three-inch standard pilot; his scarf is a strip of Sig Koverall. To simulate the 1930s cap. I daubed on baking soda and built it up with thin CyA. The visor is a piece of 1/32 ply.

The Williams Bros vintage wheels fit in nicely with the CB Associates tail wheel assembly. Top it all off with one of the superior-quality spinners from Tru-Turn, and you have a model that's appealing both on the ground and in the air.

Wing: Cut out a master rib from a piece of aluminum or thin plywood. Make short saw cuts at the No. 2 rib position and for the aileron cutoff position. Cut 26 full ribs from 3/32 balsa using the master rib. Mark the terminus of the No.2 ribs and the leading edge of the aileron ribs on 12 of these full-size ribs. Cut along the marks, and then make four extra aileron ribs..."

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