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Neil McHardy's 48" span Messerschmitt Me.262 built to 1/12th scale
and using the Eppler 205 wing section has been one of the most
successful models seen on the slope in recent years.
Here Neil provides us with the inside information on his
thinking behind the construction of this model.
Before
pen is put to paper in the design of this or any other PSS
model it is sometimes necessary to make one or two
compromises. The first is on the subject of wing area,
now it is perfectly feasible to build this aeroplane with
completely scale wings but this would however, create one or
two problems. The most obvious one being that of wing
loading, had I left the wing to scale on the Me.262 I would
have had to put up with gaping holes in it's flight
envelope. I always like to fly in virtually any wind
conditions, and on my home slope I know that very heavy wing
loadings don't work in marginal conditions. So, for
purely practical reasons I subjectively increased the wing
span and chord to steal almost another 25% wing area. If
one looks at a photograph of the Me.262 you will notice that
the aeroplane is dominated by the engine nacelles, they are
big structures. Some may be tempted to reduce these down
in size to reduce drag but this has the effect of making the
aircraft look like it is carrying a couple of missiles!
No, maintain the proportions as much as possible, in my
case I had to lengthen the nacelles due to increasing the wing
chord. I did slim them down a little, but only a very
little.
The
fuselage is as close to scale as I can get it and is fully
planked in 1/8th balsa, the formers slotted over a crutch
piece which is half the fuselage depth. I always use
planked construction as it is very strong, each strip of balsa
is pre-stressed by being bent and is probably the most
economical balsa wise. There is no great pile of sawdust
or wood shavings to clean up and all the wood you buy goes on
the aeroplane and stays there.
The
wings are veneered foam, which is recycled caravan insulation
material (which just happens to be blue foam that I got free
providing I took lots so I filled the car with it!) The
wing panels are a simple taper and the wing root extension is
sheet balsa sanded to shape. The ailerons are operated
by torque rods made from 14swg piano wire, they do not run in
tubes but are bent to shape, coated in grease and then sunk
into troughs in the wing and filled with epoxy. Some
might be alarmed at torque rods nearly 9" long but all I
can say is that they work fine!
The
engine nacelles are foam centre bodies veneered in 1/8"
balsa with the ends built up from 1/2" sheet blended
together. The intake and exhaust are made by building up
small strips of balsa around a card ring with cyano, sanded up
it's as tough as hardwood. The engine intake spinners
are made from those plastic eggs that kids get out of slot
machines at the fun fair.
The
model is finished in tissue and dope and then sprayed with
Humbrol enamels. Recently I have noticed that Humbrol
paints seem a lot 'thinner' and are almost thin enough for
spraying from the can, maybe someone could enlighten me on
this?
Initial
flying tests showed that the aeroplane had a curious tendency,
in that it had poor lateral stability, namely it weaved from
side to side. All manner of thoughts by various pundits
put this down to the flat section fin stalling, or the
nacelles overpowering the fin, I merely crept the CofG further
forward until it was stable and now it flies as if it were on
rails.
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Messerschmitt
Me.262 designed and built by Neil McHardy |
The
wing is held on by an internal rubber band which is neat but
may not be to everyone's taste, maybe a wing bolt would be a
better choice for some people. The model is to be
featured in RCMW magazine in the near future, I was asked by Simon
Rodway for an article and the drawing at the Woodvale Rallye
in August. If anyone has an interest I'm sure I could
summon up a drawing for a small consideration.
Well,
Winter draws on everyone and I hope to see more of you all in
the New Year at whatever flying gig I can get to.
Neil
McHardy.
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