3D Hobby Shop 55" Katana LIVE Build Log - Page 4 - RC Groups
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Oct 04, 2007, 05:27 PM
ExtremeFlight - 3DHS - Legacy
blucor basher's Avatar
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Oct 04, 2007, 06:16 PM
Use the 4S Luke
feathermerchant's Avatar
In American 2"
Mine is packed. All it lacks is a maiden.
Oct 04, 2007, 09:22 PM
Knife Edge Software
Servos just showed up (I'll refrain from a rant about UPS for now). I'll get them installed in the plane, and document with pics as soon as I get back from walking the dog. Maiden will be tomorrow at first light.
Oct 05, 2007, 02:57 AM
Knife Edge Software

And we're back!

OK, so there were a couple of intervening crises, but they are taken care of, and so is the completion of the tail hookups on the Kat. It's amazing how much easier this sort of thing is when you have the right servos. I had a not-so-good experience (very poor centering) with HS5245's a couple of years ago, which is why I was initially reluctant to use them here, but these seem just fine.

Rudder pull-pull is as easy as pull-pull ever is. I went ahead and set it up with pull-pull - I was in a groove, and nose-heavy is easy to fix. The elevator linkages work well - very little slop, and it all seems to be in the servo.

Nothing much left but to install the ESC and BEC and balance the ship.

All in all, two thumbs up on how easy this machine is to get together.

One neat little setup trick I'm documenting here is to glue the short aileron extensions to the sided of the fuse next to the entry hole for the wire. This keeps them from flopping around, and also makes sure that you hook the right side to the right extension, and the same for the left.

There are plenty of places to tie servo wires off to - for a ship that's going to flop around as much as this one will, it's important to restrain all the wiring, otherwise you get that annoying "whack" sound of an extension hitting covering. Also, there's always the chance that something will get wrapped around something it shouldnt.

Off to jam in some electronics and balance.
Oct 05, 2007, 04:16 AM
Knife Edge Software

OK, she's pretty much ready

Looks like it won't exactly be first light tomorrow - I'm going to bail out and go for a solid 5 hours of sleep before flying the maiden.

But in any case, all the electronics are installed, the 3S harness is soldered up, and we're ready to rock and roll. I ended up tossing a leftover CC controller in the plane, as my only Z80HV is currently on the test stand.

I'll try to talk the wife into doing vid for me in the morning. I'm stoked.
Oct 05, 2007, 04:36 AM
Knife Edge Software
Final weigh-in is 64.8 oz without battery.

My 3 packs weigh 6 oz each, and add another oz. of wiring harness, and we're at right around 5 lb 4oz. Not bad considering the heavier servos and the heavier motor (when compared with the Torque Revolution)
Oct 05, 2007, 01:12 PM
Knife Edge Software

She flewed!

Well, the maiden went quite well. I got some usable video, and the edited version is rendering now.

I started out fairly nose heavy, and backed off until I got to neutral.

The power system has plenty of pull, but as I was afraid of, I think I'm fighting a lack of pitch speed in some areas. Unfortunately, I took the wrong size wrench to the field, so I didn't get to change props. More detail on this area later...

I really like the way this plane flies. It's a very good precision ship (probably not quite as strong in this area as the SHP, but still a cut above pretty much everything else), but really shines at 3D. Rolling maneuvers are particularly nice-looking, even in high-alpha, the aileron response is very crisp and linear.

Harriers, both upright and inverted, are a bit different from what I'm used to. When stabilized, it's very solid, with maybe 5 degrees of wing rock. You can bury the elevator stick with no worries whatsoever. However, if you use standard harrier procedure of driving with the rudder, the airplane somtime snaps at you. I tried a couple of other things and found that I have much more success flying the airplane with the ailerons in harrier, and just using very small amounts of rudder to hold direction. This is pretty much backwards from how my brain is wired for harrier flight, but it seems to work very well indeed. As long as you stay mostly out of the rudder, harriers are very easy. My guess is that this has to do with how much of the vertical area is rudder, and how little of it is fin.

Tumbles aren't there yet. They're close, but I can't get the airplane to rotate strongly through the bottom of a waterfall. I think this has to do with my prop selection. When the nose comes down and the plane picks up speed, there simply isn't enough pitch speed in the prop blast to wake up the elevator. It's great over the top, but nothing happens on the bottom when I throttle up - it just loops through. I think the 14X6 or 15X6 may help this behavior, though.

All in all, 3DHobbyShop has another winner on their hands here. I'll post a link in this thread once the video is rendered and uploaded. Bear in mind that it's a conservative first flight, not an all-out 3D demo, but I think the airplanes qualities come through fairly well.
Last edited by Jeremy Sebens; Oct 06, 2007 at 07:50 PM.
Oct 05, 2007, 01:33 PM
Knife Edge Software
Video is here:
Oct 12, 2007, 03:41 PM
Knife Edge Software
Tried out the 15X6 prop - much better pitch response. The current draw at static is a fair bit higher, but the flight time doesn't seem to be shortened very much, as I don't have to dig into the throttle as much. Still want to try some 14" props, but this one definitely works.
Oct 12, 2007, 04:39 PM
Wind Powered
george@dream-flight's Avatar
Nice write up Jeremy.
Please say hello to your wife for me.
take care-

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