Curlew - Radio control sport seaplane model.
Quote: "Designed for .19 to .29 engines, the Curlew Mk II employs a unique hull design that makes take-offs and landings a joy.
If you are the same type of modeler I am, you will rarely, if ever, find exactly what you are looking for in a kit. Too big, too small, never quite what you had in mind. Well, if your interests take a turn towards seaplanes, you are really in a jam! To the best of my knowledge there are only, at the most, four seaplane kits in various stages of availability. None of these flying-boat designs with tlic exception of one .09 powered bird, is of the 'small field (or small lake) type, the balance being .45 to .60 powered ships.
What really wanted though, was a flying-boat type seaplane that could turn in a good performance using .19 to .29 size engines. This size of aircraft is quite popular these days and with the new, lightweight radio systems now available, full-house operation is very practical. Secondly, I wanted this ship to be attractive, easy to build, sturdy and innovative. I honestly believe, after building and flying two Curlews, that I have succeeded.
Obtaining useful information on R/C seaplanes, their design and operation is at best exasperating! Practically the only available data is that which can be gleaned from various construction articles that appear in model magazines. Since there is no real definitive R/C seaplane design data available, one either copies an existing design or forges ahead, leaning heavily on experience and common sense. I think the R/C seaplane is making a bid for popularity within the R/C community and that, as a result of this, many new-breed designs will be appearing in the near future. Along with these new designs could come such events as pylon racing (Schnieder Cup style?), pattern, scale, etc the possibilities are exciting and probably fairly realistic.
The first Curlew was designed, built, and flown about a year ago. I would like very much to tell you that it flew off the board but I'll be honest and tell you that it took a month and a half of constant modification and test flying to get it to the point where it was a consistent performer. However, when the mods were complete, the Curlew proved to be an outstanding seaplane. Because of the hull design, take-offs and landings were a joy. In the air - at a flying weight of 2 pounds and 13 ounces - it was capable of just about everything in the book.
The Mk II version is a distillation of all of the modifications and improvements made to the original plus slight construction modifications to lessen weight, increase strength and enhance the appearance. I honestly do not feel that the Curlew Mk.11 would make a good first R/C ship - it's fast, nimble and goes exactly where it is aimed. But, I am confident that this ship would make an excellent first R/C seaplane for the pilot who has some R/C flying under his belt.
If you have taken a look at the plans, I'm sure you noticed that a cross-section of the fuselage, forward of the step, is an inverted "V". The information on this hull design was obtained from a construction article authored by Mr Willem Aarts of Holland. The theory behind this hull was intriguing and, as I later found out quite successful on several full scale seaplanes built during the 30's and 40's. Mr Aarts explains how this hull works much better than I ever could but, in essence, the inverted V hull section performs two functions:
(1) It literally swallows its own bow wave by funneling the passing water into the center of the hull which in turn
(2) pushes the hull out of the water and onto the step.
At this point the hull is acting very similar to a racing-type hydroplane that is up on its sponsons, which id thr optimum speed mode for the hydro, and in the the Curlew's case, the optimum position to be in for take-off. This entire sequence of events takes place very quickly, allowing the Curlew to take off from a standing start in 20 to 30 feet...."
Scanning by Don at EAC, cleanup by theshadow.
Article pages, text and pics, thanks to JHatton, AugustaWest.
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