Karoro (oz4334)

 

Karoro  (oz4334) by John Sheppard from Aeromodeller 1953 - plan thumbnail

About this Plan

Karoro. Free flight floatplane, for ED Bee power.

Quote: "KARORO is the Maori word for a Seagull, and since this little cabin floatplane originates from 'down under' in New Zealand, it is a very appropriate term for a model that can alight and take off as gracefully as its namesake. Designed in 1954 so that John Sheppard could take advantage of nearby lakeside flying sites, the Karoro flew straight off the drawing board - the only adjustment required for perfect flight being an occasional twist of the ED Bee's compression vernier! First flights were made with hand launch, then an off water take off check was made. At the end of a beautiful 20 yard run, Karoro 'unstuck' and made her customary left-hand climb and smooth glide back to water level. The flexible plastic 8 x 4 in propeller was changed for a wooden equivalent, with the result that take-off was shortened considerably.

Long tail moment is a characteristic cif this simple model which makes for a very high degree of stability - even if your interest is not inclined toward a floatplane, a land version would provide you with a small sport model of the easy to build, easy to fly variety. Average duration using a 20 seconds power run with the Bee diesel is in the region of 1:20 for the floatplane.

Construction. Begin with the fuselage by pinning down two straight lengths of square longeron material and joining with spacers from F8 station rearwards. Make two sides, remove from board after marking positions for F3, F6. Pin sides upside down over plan view, add spacers from F8 rearwards, remove from board and fit F3, 4, 5, 6. Attach cabin roof, soft block, and F7, 14..."

Quote - "January 1953 Aeromodeller... Karoro is an unusual design from New Zealand by John Sheppard. It is unusual because it was designed, first and foremost, as a floatplane, with instructions on how to convert it to a land plane. Powered by an ED Bee this plane is meant to be a really fine flier. She looks as if she could easily do the business and the fact that a D/T is recommended supports that. This is one on my bucket list. If you do decide to build from my plans please take care and measure carefully."

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Karoro  (oz4334) by John Sheppard from Aeromodeller 1953 - model pic

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User comments

Hello Steve, Here is some feedback for Karoro plan 4334. I built a wheeled version, not the float version as shown in the photo, about 1959 and fitted it with a Mills .75 diesel. It balanced out perfectly at 1/3 chord, so no added balance weight was needed. A few test glides were made which turned out to be perfect so that no adjustments had to be made, either. A few drops of fuel were put into the small tank fitted to the engine, then with a couple of flicks the engine was running, the revs were set to about 1/3 full, then the model was gently launched. It lifted steadily skyward to an altitude of about 500 feet until the engine ran out of fuel, then the model slowly floated down as gently as a feather. I could scarcely believe it! Straight from the plan, straight up into the blue. I then decided to try the next flight with the engine at 'tick-over' revs, just to see how little power the model needed to fly, so 1/2 a tank of fuel was added to the now empty tank (about 1cc), and with the Mills now at minimum revs, the model was launched again. The engine produced just enough thrust to produce a very gentle climb, so I stood absolutely spellbound as Karoro gently climbed skyward. After what seemed an eternity, the engine was still running with the model slowly climbing ever higher. I hadn't appreciated just how little fuel the engine consumed ticking over, so I now began to get a little concerned as it appeared that the climb rate was increasing. The model was now so high that I could barely hear the motor, so it came as a relief when I thought it had finally stopped. I was flying in open countryside so there was plenty of space for it to float down once again, so I thought. After quite some minutes, I became totally bewildered as the model appeared to be climbing ever faster instead of descending! I stood and watched as it got even higher until it was so high I lost sight of it. There was barely any breeze, so I set off in the general direction I thought the model might be heading. About an hour later and about a mile from launch site, with my heart in my boots I climbed onto a small hillock and looked as far as I could see. Nothing obvious, but I could just make out a tiny speck in the middle of a cornfield of gold coloured stubble a long way off. The speck when I got to it, turned out to be Karoro, sitting there as large as life! That last hour taught me two things-what a superb model it is and what a thermal was all about (up 'til then, as far as I was concerned, thermals were things I'd read about in the Aeromodeller. Karoro was then put away to fly another day and when that day eventually came, about two years later, you've guessed it--a repeat performance, except that this time it landed on a putting-green at a golf course about a mile from launch-point. A golfer picked it up and was waving to show that he had it. I never knew what became of Karoro because a young relative of mine who had been with me on this last flight was desperate to have a model like it, so I gave it to him but I kept the Mills which I still have and it still functions perfectly. I've just managed to get all the necessary ingredients to mix some diesel fuel, so who knows what might happen--another Karoro? Very best wishes,
BrianHendy - 24/02/2014
I wonder how many modellers contemplating this plan realise that the designer is the same John Sheppard who featured in the famous Cranfield FAI power fly off with his equally famous Glow Worm design? John is still around and sometimes shows up at events but as far as I am aware is not actively flying. Regards all,
JohnDowling - 07/04/2014
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