Pterobat Jr (oz14015)

About this Plan

Pterobat Jr. Radio control sport aerobatic model. Wingspan 48 in, for OS 25 FSR engine.

Direct submission to Outerzone.

Quote: "The Pterobats: My modelling hobby had a five year enforced break when my wife and I became involved in a live-in motorlodge business back in the 1990's. The 'Pterobat' was the first 'serious' r/c model I designed and built following retirement from the workforce in 1998. I had dabbled with one or two simple fun-fly models but missed the smoother performance of my favoured patternships of old. Now with time in my hands I decided to see if I could produce a model with similar aerobatic ability.

I had no idea I was about to get involved in a lengthy process which involved upwards of a dozen models over the next 20-odd years. The first model [pic 005] was 60" span and had a parallel chord wing with semi-symmetrical section, and powered with an OS 40 FSR engine. It flew pretty well. Subsequent 60" span models built by me over the few years retained the same basic fuselage but wings varied between parallel and tapered chord and either semi or fully symmetrical airfoils. A couple of modelling friends also each built one or more from my plans around that time. I seem to recall we photographed nearly a dozen of them on the driveway at some stage. Somewhere along the line I ditched the clear plastic cockpit canopy in favour of silver film covered sheet balsa efforts. These appealed as easier to build and racier looking.

All these models mostly flew well in our irregular club aerobatic competitions. I never took one to the Nationals, but often did well with them in various regional competitions I attended around those times.

Further developments were variants increased to 72 inch span with OS 60 FSR power and at least one at 80" span with an OS 1.08 engine. They all flew very nicely but my favourite from thos early times was a 60" span model with tapered wing, symmetrical section, and powered with an OS 40 AX engine [pic 006]. Unfortunately none of the plans for any of these models have survived the several house moves over the years.

Among the later models was the smallest of the of the breed so far. It was built to the same basic design, tapered wing with symmetrical section, but reduced to 48" span and powered with an OS 25 FSR engine [main pic]. Plans for this model were published in RCMW in November 2005 and are the plans provided here - also with the construction article as supplement.

Subsequent to those published details, I have built at least three more models to this basic design. These were all built after our move to Australia in 2008. A plans and construction article for these later 60" span models was published in November 2014. I have included a copy of the construction article as supplement 2, but unfortunately again no plans.

That was supposedly the end to this saga. However, it didn't quite end there. Since then I have built two more - both electric powered. One is 60" span [pic 007]. It flies nicely with a G-46 motor, 60 amp ESC, and 5S 3000 lipo pack. It has a full length hatch from behind the cockpit canopy and tucked into the moulded nylon stocking cowling at the front. The larger 72" model hasn't flown yet. It was damaged in a hangar-rash accident prior to flying. These two are still in my model rack. I have since downsized my hobby involvement to mostly diesel powered vintage type models and haven`t got around to fixing it yet ....

All in all, this 'Pterobat' exercise has been an absorbing and rewarding exercise over the years. These were developed with view to producing a nice all-round performing sport aerobatic model, and I'm very happy with the result. Although I have generally moved on, I'm not sure that I'm through with this concept yet - a 40" version for a 1- 1.5cc diesel engine is currently at the doodling stage.

Alan W"

Update 12/9/2022: Added missing article files (doh, my mistake) thanks to AlanW.

Supplementary file notes

Article.
Article (Pterobat 60).

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