Tiger Moth

What can I say? I love biplanes, and the GWS Tiger Moth is just so pretty that I couldn't resist.

Everybody says it's really wind sensitive: don't fly it on a windy day, be patient and wait for a calm day. But there are no calm days here, at least not in winter. And besides, I've been practicing a lot with the Pico Stick on windy days, and that's even more sensitive to wind.

I built it almost completely stock, with three exceptions: I reinforced the wiggly plastic wing struts with balsa, I changed to smaller but beefier wheels and rubber-banded the gear wires to the wing dowells because the landing gear was too wobbly as designed, and I moved the battery into the front passenger seat since the plane wouldn't balance with the battery in the stock location under the cowling. I may modify it later, but I wanted to see how the stock Moth flew before changing anything.

I made a short test-flight at the local baseball diamond to check the trim settings, then took it to Baylands.

It flies beautifully, just as everybody says. Floats into the air in two or three feet, flies as slowly as the Pico Stick, but with more positive control and a bit less dancing in the wind. It doesn't have a lot of power with the IPS motor, even with a Li-Po battery, but it has enough to climb gradually to any altitude. It does nice loops (if I dive first to gain speed) and is quick to recover from stalls and wind gusts. Which is not to say that it's a good plane in wind; it would be much better on a calm day, and when the wind got really fierce, I retired the moth and went back to flying my Pico Stick (which may or may not be more wind sensitive, but at least it's fairly indestructible, easy to repair, and in any case it's already beat up).

And the Moth is pretty in the air! Though the dangling antenna looks a little silly. I haven't figured out what to do about that.

Oh, a note about that dangling antenna: the Tiger Moth can do really great hammerhead stalls (if you dive a little first to get some airspeed). I made a particularly good one, where the moth snapped around then dove right back down its initial trail. Woohoo! except then I brought up the engine again to fly around some more, and the engine stalled almost right away. I glided it back (no problem, the moth floats easily and I glided back to a landing right where I wanted it) and went to check on it -- and burst out laughing. See, one of the problems in flying your R/C plane right back down the path it went up is that that's exactly where your antenna is. It got caught in the prop, so much so that it took me a while to un-knot it. The motor was fine, though, as was the plane.

People ask about the transparent cowling. Mine was an unpainted Moth (which I bought by accident: I like GWS' paint scheme so well that I copied it even though I could have done anything) and the unpainted ones come with a transparent cowling. The instructions say to paint it (on the inside so it looks shiny) but I think it looks neat transparent, so I haven't painted it.

The Obligatory Pilot

Of course, the Moth had to have a worthy passenger. And Tux makes a great pilot -- now it's an free open source biplane!

Dual IPS conversion:

It's a bit underpowered with the stock IPS. I finally got tired of that (flying on a windy day where I couldn't keep up with the wind) and decided to try a dual IPS.

Several people told me that I should have installed the stick 90 degrees from the stock position if I wanted to run a dual: in other words, make the stick vertical rather than horizontal. I was first told this less than a day after I glued the stick in horizontally.

The dual IPS slips onto the same motor stick, but it turns out that it doesn't fit in the cowling that way, even aside from the thrust direction being a bit off. But it seemed worthwhile for testing. I unscrewed the cowling, slipped the IPS off and the dual on, and I was ready to test. I thought I might have to move the battery back to the rear seat, but it turns out the dual isn't that much heavier: simply moving the battery back to the rear of the front seat was enough.

It really does fly better with the dual, though. It still has the same light character, but it has enough power to combat wind and to climb to altitude more quickly. I flew around, did a couple of loops -- then the engine slipped off the front of the stick, nicking the front of the top wing with the prop as it separated. Argh! If I'd had the cowling on, that couldn't have happened.

After landing (cleanly, even with engine dangling -- the Tiger Moth is a really easy plane to land), I modified the stick: shaved a bit off each side, then added some balsa to the top and bottom to make a stick with the right orientation. Then slip the dual IPS on, a drop of CA to help hold it in place, cowling back on, and it was ready to fly again.

Other modifications:

II'd really like to have a small, slowish aerobatic biplane, and no one makes one. I'm tempted to try cutting ailerons in the Tiger Moth's wing so that it can roll as well as loop. Maybe after I crash it, so I don't feel bad about cutting up a pretty plane.

I haven't glued the gear in, because I wanted them to be easily removable since I often fly from grass fields. But it turns out it lands okay on the wheels even in grass, if I'm careful, and it hand-launches easily, so maybe I won't worry about that. For now they're taped in, and the wires are rubberbanded to the wing struts.

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