Zagi 3C

Once the wing-halves have been joined, the first thing to do is cement the three carbon-fibre spars into the base of the airframe. The wing is left in the upper foam wing-beds and weighted while the adhesive dries to ensure the airframe is "true".

I wish someone had mentioned how agressive that Super 77 adhesive is!

Here is a (fuzzy) close-up of the avionics hardware in place in four separate 'bays' cut from the foam of the wing itself. In the rear-most (top-most) bay is the FMA Rx and the switch gear (plus a mile of spaghetti). S148 servos on either side. In the front bay is a lash-up of a battery-pack. Don't ask me about it because I'm still a bit steamed! Anyway it's four Sanyo Cadnica KR-600AE cells hacked together.

Since this photograph was taken, I've changed the switch to a Switch Jack from Hollyday Designs. It works great and it's a darned shame you can't get these for larger aircraft!

Here is the completed Zagi 3C, rough as a bears arse!

Just as I was finishing it, a friend popped by and asked what remained to be done. When I said it needed to be balanced, he asked how that was done, so I plunked it down on a bottle... and it was balanced!

I just needed to adjust the control-throws, and it was ready for the air!

The photo shows the Zagi perched on top of a 5/16th dowel...

The Zagi flys fine! Better than I can pilot it...

It's tough, and bounces right back (literally!) after a crash. A bit of balance tweaking was necessary; I also replaced the winglets with red ones cut from a computer printout binder.

You can build the Zagi tough or you can build it light. I chose tough, a wise decision, given the licking it's taken since then! But obviously it doesn't float as well as it could if it were built lighter.....

Although it's a sloper, I started by bungee launching it. Everyone said "Take it out to Fortescue!" but at Fortescue they launch out over the Atlantic, and I had no desire to own an R/C submarine!

The Zagi performs well on the bungee. The original tow-hook was a bit of a lash-up attached with sticky tape! It never shifted a fraction of an inch in a couple hundred launches, but it was ugly and so I replaced it with a removable one that bolts through to two 4-40 'blind' nuts installed in the bottom of the Rx bay. There is some bass-wood sheet on the bottom to spread the load on the hook. Heavy, but tough -- and removable. So what's to complain about?

So I finally decided I was going to hurl it over a cliff. It was a joy to fly it at Fortescue! There is usually bags of lift (during the season, anyhow) and you could probably fly a wheel-barrow up there if you could get a receiver into it! At first I was hesitant to fly it out over the water. Then I was careful to avoid diving down into the "bowl". But now, I hurl it around with abandon, and have a ball with it!

And if it plunges nose-first into cruel rocks... All hail the Great Ghodd EPP!

One of the disadvantages of this is that I can't fly and take pictures at the same time. I was forced to bribe my niece to come along and take a few shots. The orange colour-scheme sure looks good against the Atlantic backdrop, doesn't it?

This photo isn't exactly level, but it's still a nice shot, I think!

Low flying is fun!

You have to be careful not to fly too low though. I've bounced off a few rocks and kept flying, but you usually have to clamber down and collect your aircraft. And the lower you go, the further down you have to clamber!

Of course, at the very bottom, there is the risk you might have to go for a swim....

Not that anything you were able to recover would be worth the effort, of course, all soaked in the briny sea...

Here is my favourite photo to date!

Who says you can't knife-edge a Zagi? I beg to differ!

This is a great shot, in close-up, and clear enough for you to see the torn and shredded condition of the tape on the underside of the aircraft.

Sweeet!

Ok, I admit, I'm not much of a pilot, but a landing this bizarre definately indicates some special skill lurking there within me!

After a particularly stunning interface with the coral rocks of the College Savannah cliff, I realised major repairs were needed when I peeled some of the tape off the nose and saw the mess that lay within. Herein is the ongoing saga of the Rebirth of a Zagi.

With the tape off it can be seen that the only thing holding the aircraft together was the tape itself and the main spar. Zagis are tough (this aeroplane was still flying fine in this condition) but years of pounding do take their toll.

Ugh! We can't leave it like this!

Over the years the leading-edge has taken a fair number of knocks and a couple bits of foam have gone missing here and there. This probably doesn't improve aerodynamic efficiency much!

The trailing-edge as well has experienced moments of high stress.

Fortunately, we can glue this tear back together...

...but new blocks of EPP have to be set into the leading-edge and later sliced and sanded to shape.

With each wing-panel shortened by about 3.5" on the root end, all that nasty dammage disappears! And we begin to see the new Zagi taking shape. It will be shorter, obviously, but possibly snappier as a result. I am investigating smaller and lighter gear to try to hold the wing-loading down as much as possible.

With new wingtips and fresh balsa elevons temporarily taped into place in preparation for preliminary balancing. Shown here leaning against her beat-up, older (and now, visibly larger) sister, the old 3C is beginning to look like a new aeroplane!

Hmmm. The old 400X looks a bit tatty too...

Slap on some orange and black packing tape, and hurl it!

Shown here leading David's Zagi out over a blustery ocean, you can hardly notice any difference in the size of the two aircraft. The cut-down Zagi probably has a higher wing-loading now (even though I replaced the servos and rx with smaller, lighter ones) so it probably won't fly as well in light-lift conditions. But it's very quick and zippy the way it is now!

It's just as much fun to fly, and with the spongy, chipped-up foam removed from the nose, the flight-gear is now held more firmly in place. With the battery pack not shifting around due to G-forces, the balance stays where it should be and you are not re-trimming the aircraft all the time.

Shown here about to pounce on an unsuspecting, yellow inferior (and, for those who know what I'm talking about, being piloted by Digital Man) the Zagi 3C is in it's element; in the air where it belongs!

My little camera will take a small QuickTime .MOVie of brief duration. Here is one of two Zagis going at it.

The yellow one with white winglets belongs to David, and the orange one with green winglets belongs to Ian. Mine was on the ground, since I was piloting the camera!

The movie is about 65 seconds long, and is only 160x120 resolution at 15 frames/second. At 3.9 megabytes you might want to pass, unless you have high-speed internet! But it does show some zagis whizzing about at our favourite cliff, and there is even a (gentle) mid-air impact! If you want it, click the thumbnail image.

At the time of this writing, there are seven known Zagis ready to fly or under rapid construction. They belong to Angus, Colin, David, Ian, Jimmy, Joe and Petra. I'd sure like to get someone with a decent camera to film that lot in action!