BuiltWithNOF

CHRISTCHURCH AND DISTRICT MODEL FLYING CLUB

75” span Short Sealand twin, for electric power, by Trevor Hewson

Trevor is a renowned builder of just a few very fine models (and all but one hang in his workshop in a pristine but well-flown state - how different from the rest of us who are lucky if we have one to display!) He chose this unusual prototype because
As for the choice of subject, I suppose it went something like this: A flying boat would be something different. No regular water site available so an amphibian would be good. The need for back - friendly easy rigging at the field ruled out biplanes. Twin engines add interest and are easy with electric power.”
The plan came from Canadian modeller Ivan Pettigrew. You can see his extensive range of plans at: http://www.geocities.com/ivansplans/ and there you will see that he specialises in lightweight structures for electric power. So any guesses as to the final weight of this 6 footer? The target (from Ivan’s website) is 60 oz with a couple of Speed 480 equivalents and eight 1700SCR nicads. - Ed
You can contact Trevor or visit his Website at
http://homepage.mac.com/trevorhewson/home/

29 Nov 2006: I finally cleared enough space on the bench to make a start. I feel much more relaxed about the wet and windy weather now!

4 Dec 2006: Boat building phase is well underway. Next stage is to sort out the main u/c mounting - and waterproof the resulting holes! Then the lower sides have to be sheeted in, including a bit of magic around the rear step area. I think I will then glass cloth the underside whilst the model still sits flat on the board. This might protect the underside from hangar rash when I turn it over to start work on the top, and would also give me the chance to do a floatation/waterproofing test whilst I can still get at the inside to plug any leaks!

The two X braces are my additions by the way. The finished model may well be strong enough to stand flight loads without them but I didn't think that it could cope with all the clamps, weights and brute force needed to persuade the sheeting to stay in place without serious risk of collapse. Heavy handed, me?!
 

A few pictures to bring you up to date:
First - the rear step before glassing. (some of you will have already seen this 'in the flesh')

After glassing, I did a leak test. I was surprised how high in the water the hull floated, even when ballasted up beyond the design weight. I'm currently working on the tail group. I was having difficulty working out an assembly sequence even before I decided to route the aerial tube up through the tailplane and fin!

After being "nearly there" for what seems like an age, I think I have now reached the point where I can put the fus to one side, have a big tidy up and make a start on the wing. Probably time to order some motors, too!

04 Feb 07 There are still some jobs where NiCd's are best!
 

02 Feb 07 Wing partly sheeted and attached to fus. Nacelles and wiring next. Any guesses at the weight at this stage? (Wheels and servos included). Span is 75ins.
 

11 Feb 07 Enough of the nacelles built now to hang the motors on and do a trial balance. So today's question is: do you think that the woodwork still to be added at the nose will counterbalance all that Profilm to go on behind the cg?

It looks like the battery will go roughly at the position shown (but not standing vertically), so I should be able to get away with the one hatch in front of the wing. The plan is to hard wire the speed controllers to the motors and leave them dangling from the wing. They can then be pulled forward via the hatch once the wing is mounted, so avoiding the need to lengthen the battery leads too much.

20 Feb 07. Snap inspection by Clive Spencer and the Editor. Trevor has completed most of the fiddly nacelle-building and installed a couple of little Hyperion outrunners (details later).  The get-together followed a visit to Brooklands to see some photos of the real thing and gather enough information for T to complete the colour scheme, which will be a scale aluminium with a red fuselage band and white cheat lines. 

There’s a lot of air in that fuselage!

4 March 07 - gone to Page 2

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