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-   -   Nitromodels Katana 50cc build thread (http://www.rcuniverse.com/forum/giant-scale-aircraft-general-467/8057710-nitromodels-katana-50cc-build-thread.html)

cpreinfalk 10-17-2008 11:51 AM

Nitromodels Katana 50cc build thread
 
I ordered a Nitromodels Katana 50cc on www.nitroplanes.com and (according to UPS tracking) it's "out for delivery". I'll start putting it together tonight and will post the adventure here, for anyone who cares. :-)

In times like these, a cheap quarter scale plane sounds like a good idea to me. I'll put in a 50cc CRRC engine in it (also cheap) and some 140oz at 4.8V Hitec servos.

Watch this thread for updates later today or tomorrow.

cpreinfalk 10-17-2008 11:53 AM

RE: Nitromodels Katana 50cc build thread
 
Also, I'll put a Spektrum AR7000 receiver in it (7 channels), 2 NiCd batteries for ignition and receiver, and I'm planning on putting a choke servo in as well.

cpreinfalk 10-18-2008 05:47 PM

RE: Nitromodels Katana 50cc build thread
 
Last night I put the (pin) hinges in for all control surfaces. The hardware for the landing gear is a bit sub-par and I had to leave the wheel pants off (the wheel axles are too short; they're just bolts, btw, and not proper axles).

flaminheli 10-18-2008 08:10 PM

RE: Nitromodels Katana 50cc build thread
 
Pics?

cpreinfalk 10-19-2008 07:48 PM

RE: Nitromodels Katana 50cc build thread
 
1 Attachment(s)
Didn't get to work on the plane since Friday night (yard sale interfered with my hobby), but I got to take some simple pictures just to give you a feel for what the plane looks like.

cpreinfalk 10-19-2008 08:02 PM

RE: Nitromodels Katana 50cc build thread
 
My plan is to finish it within the next 2 weeks and maiden it on the weekend in 2 weeks.

joseph.batson 10-19-2008 08:03 PM

RE: Nitromodels Katana 50cc build thread
 
Looks like a pretty nice plane.

cpreinfalk 10-21-2008 10:25 AM

RE: Nitromodels Katana 50cc build thread
 
Last night I put the elevator servos in. They go inside the horizontal stabs, which is nice (I guess that's standard on quarter scale planes). I haven't put in the rods yet (didn't have a lot of time last night).

I'll post some detail pics once I'm done with the elevator.

cpreinfalk 10-22-2008 12:11 PM

RE: Nitromodels Katana 50cc build thread
 
Put in the pushrods for the elevators. Today I decided to order a proper pull-pull system for the rudder, as the hardware that came with the plane is a regular one-pushrod-on-one-side-of-the-rudder kind of deal, and that doesn't seem right. Also, I bought 3.5" rubber wheels to replace the small foam wheels it came with, along with proper wheel axles to replace the simple bolt it came with.

Interestingly, the interior of the plane has no servo trays. Even for the throttle I'll have to figure out what the best placement would be for the servo and then either build a servo tray from scratch or just fit it in one of the "wholes" in the "mezzanine". For the rudder servo I'll have to do the same, as the plane is setup for a rudder servo in the back (or 2 rudder servos in the back; one on each side; but that I definitely don't want to get into).

This is my first giant scale plane. It's definitely more work and more decisions than my good old 46 size planes!! :-)

teeps80 10-22-2008 05:32 PM

RE: Nitromodels Katana 50cc build thread
 
Hey Cpreinfalk, nice looking plane you got there. Following your progress, I just built my first 50 cc plane a Chinese knock-off.

Building the plane was very frustrating.

No manuel
Hardware I would not put in a 40" sized plane
No switch cut outs
No off-set on engine box
on and on
But the plane came out really nice. My advice is don't get Frustrated, take your time keep it light and simple.

Good luck Steve

cpreinfalk 10-23-2008 06:13 AM

RE: Nitromodels Katana 50cc build thread
 
Thank you, teeps80! I finished the elevator (servos, linkages, radio programming, etc.) and the most important thing to me so far is that everything fits. There are 4 holes for each elevator and they all line up. When I built a no-name Chinese 46 size Katana, I had to re-drill most of the holes because nothing lined up. As far as that, I'm quite happy. :-)

This plane has no switch cut-outs, either.

The firewall doesn't have an offset, I definitely have to do that myself. I'm just going to use washers on the engine standoffs on the engine side. Have done that on other cheap Chinese planes.

I'm still motivated and excited!

cpreinfalk 10-23-2008 06:16 AM

RE: Nitromodels Katana 50cc build thread
 
1 Attachment(s)
Some pics of the completed elevators.

cpreinfalk 10-23-2008 06:19 AM

RE: Nitromodels Katana 50cc build thread
 
I'm getting only a half hour each night to work on the plane, that's why it's getting so slowly. Tonight I'll attack the aileron servos and control linkages. That should be a breeze (I think :-) ) and then I'll see if I can fit the wings on the fuselage. So far I put them on (to try them) with the aluminum rod and the nylon bolts, but there are 2 more holes for bolts, which I haven't checked if they line up (holes lining up is my biggest concern with cheap Chinese planes, but so far this one has been pretty nice).

cpreinfalk 10-24-2008 06:05 AM

RE: Nitromodels Katana 50cc build thread
 
Last night I put in the aileron servos (no control linkages yet).

cpreinfalk 10-24-2008 06:08 AM

RE: Nitromodels Katana 50cc build thread
 
Question to anybody who's reading this (hopeful anybody!): I have the option to put in 2 rudder servos in the back or one rudder servo with pull pull. I'm not sure which one I should do. I would think that 2 servos in the back would be better, because there's going to be more servo power, because it's two servos. I do have 2 servos with 160oz at 6V at home, so that wouldn't be a problem. Also, I have the channels available on my radio to mix it. My only concern is: since there's going to be a mechanical linkage between the 2 servos, will I even be able to install them so precisely that they won't end up pushing against each other??? Can anybody give me the pros and cons?

outssider 10-24-2008 11:46 AM

RE: Nitromodels Katana 50cc build thread
 
you already listed some of the pros and cons. other things you might think about are

1...the weight of the extra servo/extension/linkage
2...the difference in balance between two servos in the tail versus one at mid fuse

I would check my balance and go with the solution that balances best

cpreinfalk 10-24-2008 12:34 PM

RE: Nitromodels Katana 50cc build thread
 
outssider: Good point. I think I'll put in a pull pull system and will see what happens. The only disadvantage is servo power, but it's the simpler installation. I'll just live with 160oz servo for a while and then buy a 330oz servo later on.

opjose 10-24-2008 04:34 PM

RE: Nitromodels Katana 50cc build thread
 
Either put in a fairly high torque rudder servo for that pull-pull, or use two servos in tandem within the fuse.


outssider 10-25-2008 12:02 PM

RE: Nitromodels Katana 50cc build thread
 
i believe that 160 oz for that size rudder is border line ! but since you got it, try it ! make sure to use 6v. Hardest stress on that servo will be with a knife edge loop or a full power flat spin. If it holds on those, it should be ok!

opjose 10-25-2008 01:01 PM

RE: Nitromodels Katana 50cc build thread
 

Quote:

ORIGINAL: outssider

i believe that 160 oz for that size rudder is border line ! but since you got it, try it ! make sure to use 6v. Hardest stress on that servo will be with a knife edge loop or a full power flat spin. If it holds on those, it should be ok!

I agree with you, but I've found that even a single 150 oz servo ( the manufacturers of course always overstate their specs, so in reality it will be akin to 130oz/in! ).... holds fine (PROVIDED... ).

I've tried this in the 50CC Edge 540T. I had the rudder set up for high mechanical advantage...

However I also supply PLENTY of power to the servos at 6v too, which is a mistake often made.

At high draw a 160oz/in ANALOG servo can draw over 2.2 - 2.6 AMPS!!!! And that's ONE servo!

Throw in a measly 2400mAh battery pack, and there is NO WAY the servo, let alone several will hold under load.

So equally important is to provide sufficient reserve.

Of course a higher torque servo or ganging two lower torque servos is advisable, especially on the rudder.




cpreinfalk 10-25-2008 02:43 PM

RE: Nitromodels Katana 50cc build thread
 
I am using 6V. I ordered one of those Jomar glitch busters so I can use my 2500 6v NiCad JR battery for the servos only and use a separate battery for the receiver.

cpreinfalk 10-25-2008 02:45 PM

RE: Nitromodels Katana 50cc build thread
 
Today I finished the aileron hookup and the tail wheel / landing gear. Engine will be next! I'll take a picture once the engine is in place.

cpreinfalk 10-25-2008 07:12 PM

RE: Nitromodels Katana 50cc build thread
 
1 Attachment(s)
Engine is in. I also cut out the cowl, that's all done. I put the prop on without the cowl so I can start the engine (eventually, once everything's completed) and adjust the needle (if necessary).

I few words to the engine: it's (as mentioned earlier) a CRRC Pro GF50I. I got it for USD256 shipped. I know it's a cheap-o engine from China, but it should work well. I saw videos of that type engine running and people who own it, write good things about it.

I put a 20x10 Zinger on it. I also bought a 22x8 Zinger Pro, but I'll break it in with the 20x10 (as recommended in the manual).

cpreinfalk 10-26-2008 09:25 AM

RE: Nitromodels Katana 50cc build thread
 
Today (if I get to it) I will put in the throttle and choke servos and then the gas tank.

cpreinfalk 10-26-2008 05:04 PM

RE: Nitromodels Katana 50cc build thread
 
I realized that the CRRC GF50I doesn't really allow to put in a choke servo. It's one of those deals where you engage the choke and then, when you hit the throttle, the choke gets "unchoked" by a spring. So only a throttle servo, fine by me! :-) I put in a Futaba 3004, but then decided to put in one of my DS821 digital servos, because I got some laying around anyway. No big deal.


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