The question mark in the title reflects my uncertainty as to whether this project is going to work, as I've built a 32" span Spitfire MkV for Pico Stick gear and the all-up-weight is 6 oz. Will I be able to fly it at Oakmead? I rather doubt it. However, Calshot has much more elbow-room and may be okay.
In the beginning, Tony Nijhuis (how do you say his name?) published
a dog-fight double for a Speed 400 motor in the August 2002 RCM&E.
The Me 109 did not appeal but the Spit looked really excellent,
even if it did weigh 18 oz. I copied his plan and added a couple
of inches to the wing span, then built it using exactly the same
thickness of pink foam as he used of balsa, but adding a small
ply motor mount epoxied into the right place by trial and error.
His wing is a plain flat plate with a little bit of top curve:
mine is different. I had cut a curved plate section for a Bleriot
(more later) and so I used the front two-thirds of the template
to HWC a rectangular "wing". I then cut the wing plan
out of this blank and made a great mess in the garage sanding
off the excess at the TE and tips until it looked alright. Doing
it this way builds in washout automatically. It must work, because
it does not stall! RCM&E provided a very nice canopy and spinner.
Everything else was "as per" until I came to installing
the battery, receiver and aileron servo. These are housed in a
dummy "slipper" tank that fits neatly under the centre
section. It also acts as landing skid, protects the vulnerable
oil cooler and radiator from damage and has the advantage of being
exactly to scale.
I flew it for the first time (with trembling knees) one quiet evening in September, but need not have worried. It performs very well indeed, and in calm conditions looked the part, right down to the yellow prop tips. The GWS prop bends away nicely on landing and so far I've had no breakages. The motor is set up with no down or side thrust and transition from power on to glide is smooth - and it glides on and on!
But, and hence my uncertainty, it is relatively quick, even at 6 oz and a wing loading of about 4.5 oz/sq ft. I have tried flying at less than full throttle, and all seems to be well, but it doesn't exactly look like a Spitfire then! When Trevor came round to show me his Walrus (I just love that sentence, don't you?) and have a look, we discussed how it could be made to fly more slowly and really the only answer is to add lightness, or make it bigger for the same weight. A span of 36" gives about 325 sq in of wing, so if I can still keep the weight down to 6 oz, I can come in at about 3 oz/sq ft. I love the lines of the prototype Spitfire, but the PR Mk VII flew in an all-pink scheme, which is very tempting. A bit of cleaning up round the edges (no radiators, a thinner canopy and a foam spinner, less "beefing up" for outdoor flight..... well, come along and see!
(with grateful thanks to Tony Nijhuis and RCM&E)
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An early glimpse of Mike's next project. In the words of a well known TV personality, "Can you see what it is yet?" Clue: It is not another Sopwith Pup! |