Kawasaki Ki-61 Hien (oz16784)

About this Plan

Kawasaki Ki-61 Hien. Radio control scale model, for PSS or electric power. Wingspan 36-1/4 in, wing area 194 sq in.

Quote: "Now then! Stop complaining about the demise of traditional modelling skills and get stuck into this nifty fun-fighter. Kawasaki Ki-61-II Hien, by Steve Griffiths.

Among the aircraft flown by Japan's airforce and navy, the Ki-61 was something of a heretic. Its Japanese-built version of Daimler-Benz's DB601 engine (the legacy of Dr Richard Vogt, head of design at Kawasaki between 1923 and 1933 and a fan of liquid-cooled inline engines), was a striking departure from Japan's using of air-cooled radial engines - so much so, in fact, that when the Americans first encountered the Hien (or Swallow). they initially mistook it for a Bf109. Incidentally, the Allies' codename for the Ki-61 - Tony - reputedly came from it being further misidentified the Italian Macchi C202 Foglore!

The fact that the fast and manoeuvrable Hien came up against the Curtiss P-40 over New Guinea made the Kawasaki the perfect subject when I was looking to build a partner for my own model P-40. Like the Kittyhawk, my Hien was designed to be light and easy to build, yet still reasonably close to scale.

In the event, the Kawasaki turned out rather lighter than the P-40, and even with a cheap 6-volt 380-size motor it has a rather surprising turn of speed and - thanks to the properly sectioned wing - an excellent rate of climb. The model also proved its worth as a soarer by winning my local club's slope competition!

Although this plan is for the Ki-61- II (which had a more powerful version on the l's HA-40 engine), I've shown the changes you'll need to make in order to model the original Ki-61-I, which had a shorter nose and other detail differences. As yet, however, I haven't built or flown this version of the model.

Preparation: Before you can get stuck into the actual construction, you'll need to make up the wing skins, all of which can be fabricated from two sheets of 1/16 x 4 x 36" and one of 1/16 x 3 x 36". The cutting plan (Fig. 1) will help you make the most economical use of your wood, but if you can't find 4" wide sheets, I'm afraid you'll have to work out the cutting plan yourself. For best results, use PVA to join the edges of the sections, and leave the final trimming of the leading edges until the skins are fixed in place.

While you're in the prior preparation frame of mind, cut out all the remaining components and fix the central 1/32ff ply reinforcement to the main spar, which also needs to be notched to receive the ribs. A simple jig will make it easier to get the spacing and depth of the notches uniform.

I suggest that you make the wing, tailplane and fin before the fuselage. We'll start with the wing which, in the interests of simplicity, I designed without any washout. Although I haven't encountered any problems as a result, you could always build some washout into the wing if you wish, though you'll be venturing into flying territory that's presently uncharted by this model!

Ribs and Spars: Begin by marking the spar line on the bottom skin, then score the inside of the skin chord-wise along the outside edges of W2 on each panel. Align the spar centrally, and glue it to only one of the wing panels, outboard of W2. Working on the same panel, dry-fit ribs W3-W8, ensuring that they sit at right-angles to the spar and are in contact with the skin all along their length (you may need to adjust the depth of your notches to do this). Finally, glue them down behind spar.

While pressing down on the centre-section of the spar, crease the bottom skin along the score line that you made earlier, apply glue along the spar between the two W2 ribs, and attach ribs W1 and W2 each side of the centre. Next, press the free length of the spar down onto the bottom skin of the remaining panel, again creasing the skin where scored..."

Direct submission to Outerzone.

Quote: "Hi Mary and Steve, The attachment slope soarer / electric model was a free plan in RCME in January 2005. The article was originally almost unreadable white text on black background so is now reversed / inverted. The plan is already in bitmap format. Let me know if there's any issues or questions.
Many thanks yet again for your continued work on Outerzone, and best wishes for the holiday weekend to you both.
Paul D."

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