John's Second Wot 4

My first Wot4 "died" in August 2006 but I didn't get around to buying another until the following June. Even then it has taked nearly 8 months to build! This is probably the longest Wot4 build ever. I bought another "Mark 3" with tapered wing, just like its predecessor.

I've re-used the engine, an OS46LA, but had to repair the silencer with a section from my wife's vacuum cleaner. The undercarriage was salvaged too. The old model was covered with "Solarfilm". I chose "Easycoat" for this model and find it much easier to apply, and stronger as well. It's very glossy.

I fitted the engine the same way as my other Wot4, inclined at 45 degrees. This places the exhaust in a convenient position and still allows good access to the engine for priming and starting. OS46LA in Wot 4

 

 

 
You might be interested in how I joined the wing-panels. Cotton bandage & PVA wing joint Following Brian Lathey's example I used white PVA glue and cotton bandage instead of messy fibreglass bandage and resin. I glued the two panels together with white PVA glue and when this was thoroughly dry applied more PVA glue to the centre section with a brush and added a 1" strip of cotton bandage all round. More PVA was stippled into the bandage to ensure it was thoroughly soaked. Two more layers were then added in a similar way, this time with 2" bandage offset to the left and right by 1" as shown in the photograph.

  Remembered to add balancing weight before covering This picture on the left shows that for the first time ever I've remembered to add the balancing weight on the wingtip before covering the wing! (This weight balances the offset engine).

  I've added a (home-made) steerable tail wheel exactly like the one I had on my previous Wot 4. The rudder uses closed loop wires as described on the plan, but instead of using two separate wires I've threaded the wire "there-and back" on the servo arm and locked the wire to the arm with a small screw. The pictures below show what I mean Rear end detail, showing steerable tailwheel Rudder control wire locked on to servo arm

The ready-to-fly weight turned out at 4lbs 11½oz. giving a very satisfactory wing-loading of 18.4 oz/ft.


23rd April 2008 update:

Back at the pits after succesfult tes-flight We had our first short spell of decent weather yesterday and we were able to noise-test and test-fly my new wot-4.

Here she is outside the clubhouse after her test-flight.

She passed her test but, curiously, was noiser than her predecessor from the front. I say curious because it was the same engine, propeller, etc. The test-flight was uneventful - no trimming out needed, and she behaved impeccably. I think the few ounces shed in flying weight will result in sparkling performance.

I'm very happy to have a Wot-4 in my stable of 'planes again.



Click here to return to the list of John's model aeroplanes
Or here to go back to the HMAC members photogallery