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Nitromodels Katana 50cc build thread

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Old 10-08-2009, 10:56 AM
  #126
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Default RE: Nitromodels Katana 50cc build thread


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ORIGINAL: htskywalker

Well my maiden long time ago was not smooth as well, had this snap tendency but was totally corrected by re-leveling the Elevator halves. Lots of power with the DL50, already burnt 4 Gallons of Gas. It is a nice ship to fly and good on the money but surely not one of the best in the 50cc class. Move to an Aeroworks, Airwild, Dietrich, Precision Aerobatics, Krill (the best KAtana ever designed) or Wild Hare later on and you would discover how much you are missing.
I fully agree! I used the Nitro Planes Katana as my test bed (my first 50cc plane). When I crashed it after 7 flights (snapped, went out of control, lots of weirdness), I decided to get an Aeroworks Extra 260 (50cc), transferred all the gear from the crashed Katana to it and I'm very happy with it. No weirdness. :-) Don't get me wrong, with better piloting skills I wouldn't have crashed the Katana. It's just that with the Katana I had to worry during every loop about snapping on the bottom of the loop, because it happened so often with it, and even though I had only 7 flights on it (before I crashed it), I STILL worry about it on my other planes, even though it NEVER happened with any other of my planes. I guess I'm traumatized. :-)
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Old 10-08-2009, 05:03 PM
  #127
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Default RE: Nitromodels Katana 50cc build thread

I've got my eye on the CARF 2.1 Extra and the new race style Dietrich Edge 540 for the upcoming IMAC season (beginner).
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Old 10-09-2009, 12:30 AM
  #128
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Default RE: Nitromodels Katana 50cc build thread

Same concept here, NP Katana was my first Gaser. ALready bought the gear for another 50cc and ended up buying the Airwild Extra 50cc with a DA50 engine. The AW Extra is the lightest in its class around 14.5Lbs with DA50 mounted. The difference is huge in term of build and surely flight characteristics, the HW package for the AW is of the highest quality available.
Snap Rolled the KAtana once and it did not show any bad habits but I am not comfortable doing it more since I did not like its behaviour during the SR......the Katana would be in active duty till it reaches its doomed destiny....;-)
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Old 10-11-2009, 11:12 PM
  #129
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Default RE: Nitromodels Katana 50cc build thread

I've put a couple more flights on it, and have it trimmed and balanced pretty close to nuetral. It's no floater, and has to be landed pretty fast. The DLE is still going strong, but I've run into a new problem.
During the last flight i noticed a pronounced snap like you guys have mentioned earlier. the right horizontal stab failed. the ribs that keep it straight are demolished. The only thing that kept it on the plane were the two little bolts.
It flaps up and down like a bird...haha. Do any of you guys have a right side stab and elevator?
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Old 10-12-2009, 12:43 AM
  #130
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Default RE: Nitromodels Katana 50cc build thread

Well it happened with me and lucky enough I disocvered it on the ground, I had to screw the Stab tube to both halves of the stabilizer. So far the rest fo the plane is still holding :-)
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Old 11-09-2009, 12:41 PM
  #131
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Default RE: Nitromodels Katana 50cc build thread

Katana's back in action. Turns out the stab tube vibrated its way mostly into one side and caused the fiberglass tube to crack between ribs. It as an easy fix. I do need to decrease the throw on the elevator though...I'm thinking that should take care of the slight snap.
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Old 11-09-2009, 01:24 PM
  #132
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Default RE: Nitromodels Katana 50cc build thread

I Glued mine on but I'll send you my whole Carcus and wings for $80 Plus Shipping. i've considered rebuilding it but have plenty other projects going on. if you are interested, we can take it off line to Tfankyt@aol.com and send pictures of what i have... I'll throw in the Servo for the rudder and all $110 plus shipping. STill hooked up to the Pull Pull
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Old 11-19-2009, 03:44 PM
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Default RE: Nitromodels Katana 50cc build thread

Tom, Im ok for now re: the parts, but who knows what tomorrow will bring.
I used an aeroworks deflection meter to set the elevator to 25 degrees high and 15 degrees low. Flies a lot better! It's a little NOSE heavy still though. I will move the other battery from the motorbox to the tray I built above the wing tube and see how that goes
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Old 03-29-2010, 02:11 PM
  #134
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Default RE: Nitromodels Katana 50cc build thread

New to this forum, have read the posts on the Katana 50cc with interest as I have just bought one. Having a problem balancing the model at the C of G reccomended of 137mm from the leading edge. With all batteries and ignition etc positioned behingd the fire wall the Cof G is working out at 167 about 30mm tail heavy. Model weight is 7300 grams and it needs about 400 grams in the nose to correct it making the total weight too much for the wing area. I am considering moving the wings back on the fuselatge 40mm which should correct the CofG problem without adding weight. Anybody got any thoughts on or comments.

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Old 03-29-2010, 03:04 PM
  #135
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Default RE: Nitromodels Katana 50cc build thread

Can you please post a picture of your plane? There are 2 versions (one was featured in a US model plane magazine, the other one is the one that most of us got and aren't too happy with).

Mine needed about a pound of lead, which I mounted on top of the engine stand offs, and it was still slightly tail heavy.
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Old 03-30-2010, 12:28 AM
  #136
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Default RE: Nitromodels Katana 50cc build thread

I had to put all 4 batteries (1 ignition, 2 receiver, 1 smoke pump) inside the firewall along with the smoke pump and used custom engine mounts to push the engine forward as much as possible and ended up with only few grams. That should solve it. You can also check my earliest messages about areas whihc need reinforcments. Good luck, if you need to check some photos or videos www.amazrc.com
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Old 03-30-2010, 04:07 AM
  #137
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Default RE: Nitromodels Katana 50cc build thread

This model came from China it looks exactly the same as yours, sorry I'm struggling to find a way to insert a picture, new to this site. Yes I would have to add about the same say 400 grams to balance the model but I think this may put the wing loading into a criticle area. If the wing area is 1080 square inchs then a weight of 7.3 kilos about 16lbs would equate to a wing load of 34oz/square foot, adding a further 400 grams or half a pound may be criticle, and even worse if the plane is still tail heavy. Moving the wings back is the way I am thinking at the moment. Will post a pic as soon as I figure out how to do it.
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Old 03-30-2010, 04:12 AM
  #138
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Default RE: Nitromodels Katana 50cc build thread

Thanks for the post, I appreciate all the help i can get with this plane, pleased that you have solved the problem thanks for the post
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Old 03-30-2010, 04:36 AM
  #139
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Default RE: Nitromodels Katana 50cc build thread

Ok picture of Katana
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Old 03-30-2010, 06:01 AM
  #140
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Default RE: Nitromodels Katana 50cc build thread

Yes, that's the one I had. And yes, the added weight didn't help the flight characteristics at all. htskywalker is smarter than me, he moved the engine more forward. That's something that didn't even occur to me! :-) Also, I had a CRRC Pro 50cc engine in it (cheap Chinese) with a side carb. After my big crash of the Katana, I put that engine in the next plane. Eventually I replaced the engine with a DA-50 and noticed that the DA-50 has the weight further forward (rear carb), so I guess with the "right" engine the CG on the Katana would have been better and I would have needed a bit less weight.

I know you're supposed to seal the hinge gaps, but I never do that (lazy). However, I just read an article where somebody explained that it doesn't just give you more aileron authority, but it also can help a lot with "snapping out of a loop" (which mine did a lot) and it makes the plane floatier, because you don't lose as much lift through the hinge gaps. I'm going to start to do that on one of my planes now to see if I can really notice a difference. Anyway, had I done that on the Katana, I think it would have flown better. Just a thought.

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Old 05-11-2010, 02:54 PM
  #141
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Default RE: Nitromodels Katana 50cc build thread

Hi

Just read this thread from start to finish with interest as I have one of these beauties (or Pups depending what colour canopy you have!). I had no idea there were differences beyond the colour of the canopy. Mine is blue, I have adjustable wing positioning, solid stab and run a pull pull rudder. It has no added weight, balances perfectly and is a peach to fly - this was my maiden last year [link]http://www.youtube.com/watch?v=8LpucZGclDo&feature=channel[/link] - not too adventurous, and only needed a few clicks of up elevator (as you can see in the video just after take off) to trim out perfectly. The engine is a DZY48T (Twin cylinder), which fits in the cowl with just small cut outs for the plug caps (see my other little 'boring' video which has a close up - sounds awesome!!). I did have trouble slowing it down for landing - combo of high idle with new engine and not being familiar with its low speed handling!! I have no idea how much it weighs, but will check it out when I next dig it out.

Despite my comments above, I am now wondering if it is just a time bomb waiting to self destruct due to poor manufacturing / design. Should I strip out the kit and find something else?? Was there a consensus whether this one was any good or not??

Thanks
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Old 05-11-2010, 03:38 PM
  #142
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Default RE: Nitromodels Katana 50cc build thread

Akroblade954,

You have exactly the plane that I (the starter of this thread) wanted to buy, but I got a different one instead (like many others on this thread). Your plane is the one that they reviewed in FlyRC, which prompted me to buy it in first place. I'm jealous, because if they would have shipped me the right plane, I would probably still have it and I would still fly it. What you're describing is exactly what they said in FlyRC. I know a guy who writes reviews for a different airplane magazine and I asked him what they do if they get a plane for review and it turns out that the plane is real crap, and he said that they notify the manufacturer (or distributor) about it and they won't do the review at all. So I think FlyRC weren't lying about anything. That plane is really good, but unfortunately, a lot of people got a different plane.
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Old 05-11-2010, 03:50 PM
  #143
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Default RE: Nitromodels Katana 50cc build thread


Quote:
ORIGINAL: cpreinfalk


I know you're supposed to seal the hinge gaps, but I never do that (lazy). However, I just read an article where somebody explained that it doesn't just give you more aileron authority, but it also can help a lot with ''snapping out of a loop'' (which mine did a lot) and it makes the plane floatier, because you don't lose as much lift through the hinge gaps. I'm going to start to do that on one of my planes now to see if I can really notice a difference. Anyway, had I done that on the Katana, I think it would have flown better. Just a thought.

Re: Lift

Unless there is a huge gap, you are NOT going to loose lift because of hinge gaps.

Ever see a 727 with all of it's surfaces extended? Lots of lift there with no "sealing" of those VERY LARGE gaps.

With RC planes we are talking about the diameter of a pin or more, in terms of gaps. Sealing the gap does nothing to affect this... nor does it affect snapping out of a loop.

The only reason sealing the hinges helps with flutter is because it helps re-inforce the hinge line, thereby lessening lateral harmonic resonance caused by the airflow over the wing... not airflow THROUGH the gap itself.

You can achieve the same effect via other means even if you have a gap... e.g. more servos on the surface, counterweights, a stronger main servo with a lateral stiffner on the control surface, etc.

You DO NOT get "more" aileron authority for the same reasons. Air simply does not flow through the very small gaps we put on RC planes, lessening control surface effectiveness.

Someone is applying fairly large ( full size ) scale thinking principles to our small planes in saying that.


To cure your snapping out of a loop, either INCREASE or DECREASE your elevator throws and laterally balance your plane.

As it is your wings are not stalling at exactly the same time. Increasing the throws speeds up the stall interval, lessening the chance of them stalling at different times.

Also test your plane's snap tendancy by putting it into a slightly powered dive from a high altitude, then backing off the throttle completely.

Let it decend for a second or two then pull up hard. Does the plane still snap this way?

If not engine torque is probably in large part to blame.


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Old 05-11-2010, 04:11 PM
  #144
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Default RE: Nitromodels Katana 50cc build thread

Quote:
ORIGINAL: cpreinfalk

Akroblade954,

You have exactly the plane that I (the starter of this thread) wanted to buy, but I got a different one instead (like many others on this thread). Your plane is the one that they reviewed in FlyRC, which prompted me to buy it in first place. I'm jealous, because if they would have shipped me the right plane, I would probably still have it and I would still fly it. What you're describing is exactly what they said in FlyRC. I know a guy who writes reviews for a different airplane magazine and I asked him what they do if they get a plane for review and it turns out that the plane is real crap, and he said that they notify the manufacturer (or distributor) about it and they won't do the review at all. So I think FlyRC weren't lying about anything. That plane is really good, but unfortunately, a lot of people got a different plane.
Thanks for the confidence boost. This is my only larger scale petrol/gas model (until I make up my mind whether to buy the ASM Cessna 182 )and I would be devastated (as you clearly are) if it were to come down hard due to poor design or manufacturing - I can just about cope with pilot error (my first Boomerang Jets Elan RIP !!!!!).

I didn't fly the Katana that much last year due to lack of time and also doing some damage to one of the elevators on a dead stick landing - elevators point down a long way on full up elevator!! BTW, dead stick was due to poor in flight running on the (real) maiden, which only lasted 45 seconds. Second flight also lasted about the same!! Turns out, I needed to route the carb vent hole back into the fuz as the prop wash pressure was causing the mixture to lean right off to almost nothing. All sorted and ultra reliable now.....

Sorry about your model and thanks again
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Old 05-12-2010, 03:14 AM
  #145
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Default RE: Nitromodels Katana 50cc build thread

The Katana was my first Gas plane as well but it took lots of modification to make it airworthy but still the Flying Characteristics are not impressive at all. Once you buy a good standard model (the $600 category ) you would be in the real business.
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Old 05-18-2010, 02:52 PM
  #146
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Default RE: Nitromodels Katana 50cc build thread

The Katana is just about ready for maiden flight have run up the DLE 55 engine in the garden it starts real well and hoping for some good weather in the next few days. Mine is the clear canopy one but apart from that looks identical to the others, apart from the adjustable wing positioning.

To avoid the extra weight needed to get the right balance I have moved the wings aft 34mm, with all batteries behind the firewall the CofG comes out spot on. Hope this mod does the trick and does not effect any other flying characteristics adversely.

This is my first gas model, flying a WOT4 at present, the weather in the UK is cold and windy so looking forward to some better flying weather for the Katana. This is my first year as a born again pilot, last flew in the 1970's with none proportional gear in an own planned and built Concord.

Pics of Katana and Concord, thats me on the left

Southport UK

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Old 07-09-2010, 06:24 AM
  #147
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Default RE: Nitromodels Katana 50cc build thread

Just a summary of the mods carried out to this Katana, the wings were moved aft 34mm which made the final balance once the prop and spinner had been fitted, slightly nose heavy. I fitted a battery backer using two 3300 mAH sub C NiMH which also added to the forward weight.
All in all final balance is slightly nose down with the fuel tank and batteries moved close to the C of G point. The weight has come out at 16.5 lbs without the need to add any to balance the model.

The maiden flight was good with just simple circuits, some slow speed passes and an attempt to stall the plane at a safe height. Whilst no loops rolls etc were attempted the plane handled well and even when landing at a less than intended speed there was no sign of stalling.

A heavy landing on the second flight caused the undercarriage to break off and some damage to the cowl and engine exhaust.  Have beefed up the undercarriage mounting and fitted larger softer wheels. Hoping to use this model to try out more aerobatic moves as my skills improove.

 In the UK The British Model Flying Association R/C Achievment Scheme encourages newcomers to take the various certificates starting with the 'A' certificate (which I have just passed) and going on to 'B' Certificate which reconises the pilot's more advanced ability.

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Old 07-09-2010, 09:03 AM
  #148
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Default RE: Nitromodels Katana 50cc build thread

Sounds good! Good luck! I hope you won't have too many problems with heavy landings. For a while I had to replace the prop after every flight because of hard landings where the prop hit the ground and broke (on my 50cc Aeroworks Extra 260)! :-) $25 a flight! When I had the Katana (the one you currently have), I had no problems with landings, it just suited me.

The fun really starts when you are so comfortable flying this big plane so that you're not nervous anymore and you just fly it like it's a little foamie. I keep a log of all my flights and it took me about 60 flights between the Katana and the Extra until I got really comfortable (that was last weekend) and I did low level harriers and things like that, which I've done with foamies for over 2 years now. For a while I even hesitated to bring my big Extra to the field, because I couldn't enjoy it, but recently it's the only plane I'm taking with me, that's why I got so comfortable with it.

This hobby is just awesome ... :-)
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Old 08-04-2012, 05:14 PM
  #149
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Default RE: Nitromodels Katana 50cc build thread

Does anyone have an instruction book for the Katana 50 cc ARF, I need one real bad. Thanks
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Old 08-04-2012, 05:16 PM
  #150
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Default RE: Nitromodels Katana 50cc build thread

Does anyone have an instruction book for the Katana 50cc, I need one real bad. Thanks
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