Not quite giant at 72" but need help.

[mcharles13]

I posted this in the glow to electric section and got no replies so i figured i'd try here.

I traded a friend of mine some equipment and scored a CMP 72" Katana.

He got it from a clubmate of ours who had it seriously underpowered. The covering is pretty dang ugly but it was designed by the original guy for visibility above all else.

I'm peeling off the old covering and have noticed underneath the original ARF covering looks like vinyl. Whatever it is it's pretty dang thick. He reskinned on top of the old skin. Never bothered to remove it. Anyway i need suggestions on a power system that will allow me to 3D it. It will be A123 powered. I'm thinking of putting a clone 5330 in it. Will that be enough?

Also when i reskin it is there any "best option" skin for such a large bird or can i just use what i know? Since it was skinned in vinyl it made me wonder if it needs a thick skin or if that is only cause it was glow before.

Any help appreciated.

,mike

[blucor basher]

Ultracote. It's already heavy, I doubt you'll need any specific strength skin. It's listed as 11 lbs. on glow on the RaidenTech site...I'm not sure 3D is in its future. Personally, my choice for power would be Hacker A60S (or Hyperion 5025). Cut all the lightening holes you can during the re-cover, you could spend a bunch of money on carbon parts to lower the weight...but I'd fly it before deciding to spend any more on it. If it's bad, you can use the parts in a light airplane like an ExtremeFlight 74" Yak.

[mcharles13]

Thanks blue.

What is a good indicator of what makes a good 3d plane for these large sizes? Basically i'm curious how you determined so quickly it won't 3d well. (as detailed as possible if you can. i love learning)

,mike

[tIANcI]

Mike ... this baby is heavy, even with a 160 sized motor or 26cc gasser she flies heavy. Perhaps it would be better to choose another plane if you want a 3D EP plane.

3D is about power to weight ratio based (factoring in the wing area too). Nowadays, 74" 3D planes are having an AUW of about 10-11 lbs only. The CMP Katana stated AUW is the lowest they can get it on the smallest power plant I think. This baby averages 12.5 lbs.

A clone 5330 should be fine on a 12 lbs plane, you will be looking at a 20x10 prop and that will give you very good performance on a 12 lbs plane.


Enjoy reading this:

http://www.rcuniverse.com/forum/m_1050950/anchors_1050950/mpage_1/key_cmp%252Ckatana/anchor/tm.htm#1050950

[mexico]

Charles - I don't know if I did the metric to english conversion correctly but I think the Katana (72" span) has 992 squares for wing area in comparison to an EF Yak54 (74" span) that has 1120 squares. Assuming they both can be outfitted around 12 lbs it doesn't appear to be too bad. Maybe Ben has some specific knowledge of how that planes flies when he says it won't 3d well.

[blucor basher]

I would suspect that, without any mods, it'll come in over 12 lbs., and under 1,000 squares on that particular wing, I suspect it will wing rock pretty severely. It just seems, since so much effort will be expended on the project, that if good 3D perfromance is desired, it might be better to start with a really capable airframe. It is very pretty, however.

[mcharles13]

I would suspect that, without any mods, it'll come in over 12 lbs., and under 1,000 squares on that particular wing, I suspect it will wing rock pretty severely. It just seems, since so much effort will be expended on the project, that if good 3D perfromance is desired, it might be better to start with a really capable airframe. It is very pretty, however.

Hmm...i'll abandon the 3d idea with this plane and just fly it sport. I like your planes though. When that 85" edge debut's i might grab one and use that as my 3d beast!

As for the covering i think it is UGLY. I've already pulled it all off and am inspecting where i can lighten it. It seems the previous owner had already dremeled out some areas.

I'll treat this one as a beater plane to hone my skills :)

Thanks for help and as soon as my next batch of cells arrive i'm sendin you and sun.flyer the test pack.

,mike

[mexico]

Ben - do you have an approx weight of the 85" Extra all up less the main packs?

[blucor basher]

Not yet, I want to test a few structures and make sure of them before posting info like that. We've gone for some radical stuff this time.

[redflyboy122]

i have this plane and fly it on glow. dont know the weight but it was not 3d machine. it was flying on a webra 120 and was not enough for uplines. was going to put an os 160 in it but have decided to sell it and get the yak 54 74" from EF. the katana would stall and wingrock pretty viloently if i pulled up hard at slow speeds. never tried hovering as i didnt have enough power. hope this helps. as mentioned above if 3d is your thing get a different plane is my suggestion. it is great for imac though!

[mexico]

Maybe I can ask my question a different way. Ben - knowing what you know - could you see it flying well carrying 4 1/2 lbs of batteries?

[blucor basher]

Absolutely.

[mexico]

That is exciting. That means that if you outfit it with a motor prop esc combo that can draw 85 amps and run 12s2p A123 cells you should produce more than 3000 watts and the main pack will be doable at around $240. Plus the ability to charge in 15 minutes. That's too good.

[tIANcI]

BB - with about 12 lbs you might want to consider the 5035-18, that will give you really good performance.

[blucor basher]

Yeah, we have a 74" Yak with that motor, it's sort of overkill. I like the other one w/ the 5025 better.

[tIANcI]

BB - over powering is the name of the game in 3D right? Hehehehe ...