SLOPING OFF...

...the Newsletter of Christchurch and District Model Flying Club for September 2021

WALRUS WOES
by Mike Roach

I was 13 when this copy of "Aeromodeller" came through the letter box. I had an annual subscription for Christmas every year since I was ten,  but this issue was something special as it featured a very accurate  scale model of the Walrus. At that age it was completely outside my  ability, but oh, the looking that magazine got! The plan was "by  Aeromodeller staff" from HJ Wright's free flight model. It looked  wonderful.

But first, back in November 2004, I started a depron Walrus, based on  TrevorH's all-yellow version that I had seen flying at the Calshot  velodrome. With his help I drew up the plan (available on the Outerzone). This was in the days of GWS geared brushed motors and just on the  transition to LiPoly batteries. The models were very successful and  occasionally flew together at Calshot. His is still around of course,  but mine became the victim of an off-water attempt in Christchurch  Harbour that did not end well, but here they are at Fawcetts Field in 2005, flying together by virtue of Trevor’s skill...at photoshopping

Moving on, I found the Aeromodeller plan on Outerzone and had it enlarged from 38" span to 54", and this is where the fun  starts. I have a Park 480 spare and with a 30A SC, 4-bladed 10" prop and four servos, I was off

The build went reasonably well, there were quite a few alterations necessary to convert free flight to RC but in the end it was starting to look pretty good. The dummy engine pod, made from cornflakes packets, was to ensure I hade the right length and inclination for the struts that hold it all together

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And here the Walrus Woes started. I found it really difficult to get all the struts and all the surfaces in the right place at the right time. The pod struts were not too bad, 2mm steel wire bent up and sewn to the ply dihedral braces. The wings are directly above one-another in side view, but of course the struts must be inclined forward to counter the incidence of the wings, so it’s not that straightforward. Also my agricultural method of attaching the struts to the wings didn’t help.

Then there’s the retracting undercarriage. It does look reasonably simple on the plans, and I’ve seen the one at the Fleet Air Arm Museum at Yeovil, but I made a complete hash of the very first step, locating the retract unit. It should have been further back, but I got the angles wrong and paradoxically, to get the wheels into the wells under the lower wing, they had to be far too far back in the down position. This means the model scurries about nose down on the grass like a spaniel puppy, causing much amusement in the cheap seats but little actual take-off. So I had to use excessive up elevator for getting away and immediately revert to normal rates once safely in the air.

I have to admit that she looked pretty good on the ground despite all the hassle involved in building the thing. But as the maiden and subsequent flights proved...

...that’s not the whoile story!

The Aeromodeller plan has the CG behind the step and I must admit that bearing in mind the sweepback this seems logical. But flawed. Ten seconds of furious “not-flight” and I moved it forward to the location I’d used on the little depron model, about the same distance in front of the step as the other was behind. Well, she flew. It was very untidy and not at all calming. She porpoised badly under power as I struggled to catch up with the elevator, then with power off, she almost leaped into a climb. Various experiments later made little difference, so I removed the retracts and covered over the holes with film and took her to Longham where just for a few moments I was lulled into just how lovely she looked on the water

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Unfortunately the flight characteristics were no better and she ended up in the weeds and I had a long wade in my knickers to get her back and then had to dry her out and re-rig all the broken wires. Amazingly the electronics all worked . The second attempt was worse and David B had to go to the rescue

Dried out and re-rigged yet again, she hangs a little forlornly in my shed until the weed clears from the lake and I can try again. Bang goes any chance at the C&F!