About this Plan
Akro-Kat (Akrokat). Control line sport / stunt trainer by Dave Cowburn. For .19 to .25 power. Free plan with Aeromodeller, September 1985.
Direct submission to Outerzone.
Update 8/6/2022: Added article, thanks to Robin Lewis.
Quote: "Hi Mary/Steve, I really fancy building this model, but noticed there was no accompanying article. After a bit of digging I managed to acquire a copy of Aeromodeller September 1985, so attached is a scan of the accompanying (and very comprehensive) build article. Hope it’s of use. Kind Regards,"
Quote: "Aktro-Kat, by Dave Cowburn. Do you want to move into control line aerobatics? Then buld this no frills stunter.
Why Control Line? On a fun/money basis Control Line is hard to beat; a model like 'Akro-kat' can be built for about £25 including engine and control system. You would pay more than that for a R/C model kit and still have to pay at least £80 more for engine and radio!
C/L models are easy to build: the components are durable enough for the most fumble-fingered to handle without `dissolving into dust' and the skills learned can be passed on to other branches of the hobby if/when interests change or finances permit.
Almost any patch of grass (playing field) is a potential flying site and a pint of diesel fuel lasts all weekend.
For the budding designer, almost anything will fly (even if not very well) and, once again, skills learned stand you in good stead for later projects in other areas.
The scope for C/L models on the contest scene is wide, in short C/L is good in its own right as well as being an excellent introduction to other areas of model flight. Many of you wireless types don't know what you are missing, why not build an Akro-kat to play with when your frequency is full or your batteries are flat?
Akro-kat is tame enough for a novice to fly safely yet acrobatic enough not to be boring for the more competent pilot - all a 'sport' (ie fun) model should be!
The model: A trainer with aerobatic capability may at first sight seem to be a contradiction in terms. However, experience has shown that a model of this type is in fact much easier to fly than many traditional trainers which are often over-weight and under-powered and require constant 'nursing' from the pilot to remain airborne. High wing loading often causing an abrupt return to earth at the slightest mistake on the part of the (inexperienced) pilot.
A well developed racing model is better, but in this case dizziness becomes a major problem for the trainee pilot and once again the earth has an unfortunate habit of getting in the way.
The easiest models to fly are undoubtedly the full-stunt models, being smooth, responsive and slow. Their only drawback being their inherent fragility and long building time. Improve the strength and reduce the building time and. to my mind, you have the ideal trainer.
Properly designed (and built) it will fly level easily without having to be coaxed into the air, and its inherent manouverability will allow the pilot the chance to recover from the kind of desperate situation in which a solid trainer would be removing divots from the flying field. Also, the model will still be interesting to fly once the first hurdles of C/L flight have been crossed.
With these thoughts in mind Akro-kat was designed. A constant chord wing was chosen for simple building, flaps being deleted from the full-stunt specification as the model would not be required to perform square manoeuvres. A simple box fuselage was chosen for several reasons, firstly they. look better than a profile (and most people like their models to look like a real plane), secondly they need not be more difficult to build than a well developed profile fuselage..."
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User commentsSteve and Mary, G'day I hope this finds you well, attached is 2 pics of reasonably recent builds that I've completed. First is a Dave Cowburn Akrokat [pic 005], this model is powered by a Jena 2.5cc Diesel and flies well tho' I haven't "rung" it out yet, we're waiting for some nice weather, a lot of sanding and shaping involved with the leading edge of the wing and top deck being solid balsa sheet ~12mm, I've had a copy of this plan for ~25 years and always wanted to have a crack at building it, anyway here it is... Cheers,
Clive Parsons - 27/08/2022
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