Shearwater (oz8136)

About this Plan

Shearwater. Radio control flying boat model. Cox Medallion with throttle shown.

Quote: "Flying boats have always had a special appeal to me, and judging from the number of requests I get for flying boat designs, a lot of you modelers are similarly inclined.

There's nothing prettier to see in aeromodeling than the sight of a model flying boat taxiing out from the shore, with the bow wave curling out and leaving a rippling wake, then, as full power is applied, the boat surges up on the step, picks up speed, skips a couple of times, and then lifts into the air with the water dripping off the hull and punctuating the end of the boat's wake with a series of little splashes.

Or, maybe it's just as pretty at the end of the flight to watch the flying boat gliding in over the water, particularly if the latter is smooth, and seeing the boat come down, meet its reflection and destroy it with the wake as the ship slides over the water, slows down, and sinks into floating position to taxi back to shore.

In between the takeoff and landing, the sleek appearance in flight with no landing gear hanging down, adds to the overall beauty of the flight of the flying boat. No wonder they're popular. And there are some real beauties on the market, too. Jetco's Navigator (oz306) is a classic, and you can still find a Berkeley Privateer 15 (oz269) in some shops, But man! The work involved! Great for the dedicated modeler who loves construction detail, and a chore for those who don't! I'm one of the latter - a disciple of simplicity in construction.

So, I established an objective for a new flying boat design - it should be as simple as possible to build, yet be seaworthy and airworthy. And pretty, too! What's the simplest fuselage to build? The box type - sides perpendicular to the top and bottom. Okay. Do away with the sloping side and 'V' bottom of earlier flying boat designs like the Dreamboat (oz2167) and the Lil Swell (oz821) I knew the flat bottomed hull would work, the Hydrohoney (oz308) proved that, so a profile was sketched. A flat bottom makes a bow wave that doesn't curl away until the boat is on the step. Instead, the wave breaks forward, like the bow wave on a barge. So, a long nose with a gentle upswing on the bottom will minimize the spray from the bow wave when the boat is taxiing. It also helps the model to rise to the step.

The corners between the sides of the hull and the bottom should be sharp, but the corners at the top can be rounded to minimize the boxy appearance. 1/4 in longerons the full length of the hull allow you to round the corners off - and suddenly the hull doesn't look boxy!

Next simplification - mount the engine pylon directly to the hull instead of the wing. Makes it easier to set up engine control and easier to build the wing. Then, put runners along the top of the hull so the wing is cradled to allow a simple dihedral joint.

Sheet balsa for the tail surfaces is as simple as you can get, so use it. One of the easiest wings to build is the Schoolmaster (oz7534) wing, so that's what's shown on the plans. However, you'll note from some of the photos that I used a built-up wing. Why? Because I had it on hand. It is the prototype wing for the Schoolmaster before we went to the full sheet construction. Like I say - do it the easy way.

Before going into the construction, let me tell you about the name. I showed the profile to my son, Don, and said - How do you like that? Don't you think it'll slice through the water real nice on takeoff?

Don is interested in shore birds, such as Terns, Curlews, etc. He disappeared into his library, and came back in a few minutes and said - you should call it the Shearwater. That's a fast flying bird that lives around water and is sorta' long and sleek.

So I did. It fits.

You'll also get a kick out of the story behind the beautiful Shearwater in German patrol boat markings. Scott Christensen, a local modeling friend, built it, without plans, by copying mine - and then he drew the plans after the plane was finished! And we're using his plans because they're excellent to work with.

Now, a few words on construction.

Hull: This goes together real easy. Only one part is a little tricky, and that's pulling the sides together at the nose. The two sheet sides should be of the same consistency balsa so they will bend equally. But, to be absolutely sure the forward bend is equal, pull the sides in, hold them tight against the crossbraces at the nose, either clamped or with rubber bands as the photo shows, then check the curvature of both sides. If it's not even (mine wasn't), then put in a temporary diagonal brace which is just long enough to force the sides to equal curvature. Now, glue the crossbraces and the nose block firmly in place and let dry thoroughly. Leave the brace in until you've sheeted the bottom of the hull - and thus the equal curvature is assured..."

Note this is a low resolution plan.

Update 26/10/2016: Added article, thanks to RFJ.

Supplementary file notes

Article.

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