christchurch and district model flying club

Piper L4 Grasshopper by Ken Spokes

Some three or four years ago, I started to build a 1/4 scale Piper J3 Cub from Mick Smart plans but as sometimes happens, I ran out of enthusiasm and cocooned all the parts in newspaper and stored them in the loft There they remained until a few weeks ago when curiosity prompted me to see how they had survived in the unbelievably high temperatures in the loft in the summertime.. Amazingly, I found that everything was as good as the day it was stored - at the very least, I would have expected something to be warped. I was also pleasantly surprised to find that I had built far more than I had thought. Most of the main parts were there but far from finished.

It seemed a pity to put it away again but if work was to restart. then a few thing needed thinking about. Originally, I had intended powering it with a 90 FS and work at the front end had been completed with this in mind.. Could it now be converted to electric?. Looking on the web, I found numerous articles showing how it could be done and detailing all the hardware needed. Most suggested an Axi 5320/28 with a Jeti 90 Opto controller, a 20/10 prop and a 10c 3200 lipo battery pack. This setup would give over 2Kw of power but what about the weight? I was quite pleased to find that the total so far was just over 6lbs. Still to be added would be the covering (Solartex), radio gear, servos and all the other odds and ends that mysteriously seem to add on the pounds plus of course, the motor, batteries and controller. Anyway, this was encouraging, and I am hoping the final weight might not exceed fourteen pounds. So far so good, but the next question was, would an Axi 5320 fit in the moulded cowl I had bought particularly as I was hoping to fit a dummy engine which would encroach on the inside space.. To check this out, I made a replica motor out of wood and was relieved to find that it did - just about.

As I mentioned, the Cub had so far been built as a J3 which I was now thinking of converting to the L4 military version. This would require major dismantling of the cabin area and a large greenhouse built in its place. After much pondering, I decided it was worth doing although  I was not too sure how successful I might be with the glazing.

Finally, as with the Storch, I had to decide just how much detail I wished to include. As there was no pressure to meet a time scale, and as I really enjoy building, I have decided to go the whole hog and make it as faithful a replica as I can ( and become a member of the rivet counters club.- luckily, the Cub has relatively few )

As the Cub has been around for many years, there is no shortage of information An excellent source is the January 1979 issue of the Aero Modeller which featured the Cub in its Aircraft Described series with detailed drawings and a great colour photo of the L4 on the cover. Also, as you can imagine, there are pictures galore on the Web, so no excuse not to get thing right.

Sept 2007. The work of chopping out the J3 cabin and putting in the struts for the new one has now been completed. The main problem I had was keeping everything in alignment during the rebuild which was solved by placing a number of cardboard jigs inside the cabin. Also, thinking ahead to the glazing, it was necessary to ensure that each strut was at the correct angle and flush with the fuselage sides. Next, for a complete change, I tried my hand at fabricating a scale tailwheel assembly. The three leaf springs were ground and bent out of an old hacksaw blade which together seem to give just about the right amount of flex. The other parts were made  from bits of metal found in the scrap box and brazed together. I'm happy that it looks something like the real thing. To be continued)

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