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Old Mar 02, 2007, 06:13 PM
buy a lot, fly a little!
stuart warne's Avatar
Hong Kong, Hong Kong Island, Central And Western District
Joined May 2001
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PRU Blue FSK Spitfire ready to go...any last min pointers?

Hello all, here’s the result of my labour. This was the FSK Spitfire that I got off ebay for £25 ($55 I think) in December, and after quite a few late evening/weekends (I spent more time looking at it than working on it ), she's ready for the maiden so I'd though I'd share before I chance her being no more . I'm running an Axi 22/12/20 on the standard FSK prop through a CC Thunderbird 18amp esc on a 3 cell 1200 flightpower pack and a schulze 4 ch rx. I've also added a rudder to aid the initial torque roll to the left and generally benefit flight control etc. I'm going to weight it later, I hope it shouldn't be over 15oz, but with the paint I'll be interested to see what it comes out @. The model now represents that involved in the highest combat ever recorded in WW2, interesting story and nice to show it through the model. Also tried my hand at weathering (silver dry brushing on fairings etc and the black pen drawn in the panel lines) to help bring the model out a little more. Some pictures in the sun tomorrow pre maiden should show more, but I'm happy. Just missing the roundals on the sides of the fuzz (waiting for print cartridge to arrive tomorrow) then its fully complete, but I test fly it before then I hope.

I believe there have been a few threads on this and other FSK fighters, here and in the scale forum (I'll post this there too), but I'd just like to ask if anyone has any particular tips for this model? Notably if anybody has the model setup differently to recommended in the instructions (movements CG etc) I expect it to fly on par with the Alfa’s that I have, if maybe a little more skittish in the air with the scale wing etc, but any suggestions?

One thing though that I noticed when test running the electronics/battery motor etc on the ground (my bedroom) was that only after 30sec's the motor was hot to touch and both the esc and battery were very warm I realise there was no air running through the model and over the components, but I was more than a little concerned. Wasn't sure why it was getting sooooo hot, but have now added more air in and air out holes and I'll watch the situation, but any suggestions why? Other than that just waiting for the weather to give me a break this weekend.

Stuart.
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Old Mar 02, 2007, 07:06 PM
buy a lot, fly a little!
stuart warne's Avatar
Hong Kong, Hong Kong Island, Central And Western District
Joined May 2001
5,657 Posts
Just weighted it. AUW with lipo is 14oz, lightest warbird I have. Feel a bit better now
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Old Mar 02, 2007, 07:27 PM
Hooper, full throttle!
Tommy D's Avatar
USA, NY, East Islip
Joined Feb 2004
11,048 Posts
Your model looks great

The 2212-20 has a KV thats pretty darn hot for a FSK 4 blade prop. I would bet if you put a meter on it you are well over amped of what AXI reccomends.

That said if your over amping your motor you asking a lot out a little 1200 MA pack. Heat, heat and more heat with no cooling is not a good thing.

If you have to fly it on the 4 blade I would keep it to no more then 1/2 throttle.

How about a nice APC 8x6E for the maiden?

Best of luck to you.

Tommy D
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Old Mar 02, 2007, 07:46 PM
The sky is my playground.
Dora Nine's Avatar
United States, NH
Joined May 2005
7,631 Posts
Looks damn good to me. Any thoughts on weathering? And what about some roundels for the fuse? Be sure to post some in-flight pics if you can.
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Old Mar 02, 2007, 07:47 PM
buy a lot, fly a little!
stuart warne's Avatar
Hong Kong, Hong Kong Island, Central And Western District
Joined May 2001
5,657 Posts
Hey Tommy I think you've hit the nail on the head their. I was just reading through old posts an it was then i struct me. Well I'll go down to the LHS tomorrow and see if they've got a prop and spinner to match. I just hope the spinner will look as close to scale as the fsk one, or maybe I could recut it. If not, (being a bad man and not having a watt meter, maybe I'll get onen of those too) I'll set 2/3 throttle to full throttle on my Tx and just land after my first circuit and 'see how it feels'.

Thanks tommy
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Old Mar 02, 2007, 07:52 PM
buy a lot, fly a little!
stuart warne's Avatar
Hong Kong, Hong Kong Island, Central And Western District
Joined May 2001
5,657 Posts
Hey dora. I've actually weathered the model but the light was crappy in the bed room, so I bet you'll be to see it better when I take some pictures outside tomorrow. The roundals, as I said, just waiting on the printer cartridge to arrive so I can print them off. Once thats done I'll add exhaust stains down each side of the fuzz with a ink pen trick I tought myself, then varnish to seal.

If i can get the model and myself happy with this new prop issue, and if the weather plays ball i should have some in flight pics this weekend.
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Old Mar 02, 2007, 07:58 PM
Hooper, full throttle!
Tommy D's Avatar
USA, NY, East Islip
Joined Feb 2004
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Stuart get yourself a meter <borrow one if you have to!> ASAP! Or bring your model down to the LHS and let them test your current setup on 2S not 3S. I could be wrong but I would be willing to bet even on 2S your pushing the edge.

I just took notice to your ESC and it's rated for 18a. I would really hate to see that Spitty go in if the ESC burned up.

My first fast little warbirds <like you have> a few years ago ran the Axi 2212-20 with a CC-25 ESC and an Aeronaut 8.5x6 prop. It was pretty quick on the old Tanic brand 1550 3s <10/12c> but you had to use some form of throttle management and cooling was a must. Easy on a radial cowl model.

Best of luck to you and let us know how you make out.

Tommy D

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Last edited by Tommy D; Mar 02, 2007 at 08:07 PM.
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Old Mar 02, 2007, 08:11 PM
buy a lot, fly a little!
stuart warne's Avatar
Hong Kong, Hong Kong Island, Central And Western District
Joined May 2001
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Tommy, i'm certain this is why my setup got so hot was because these of combinations. Might I even try a smaller axi motor, seems like my motor choice is too hot. Well if I carn't get to the LHS tomorrow I'll set the throttle to about half I guess and check it after the first hop. Damm, this is a pain in the but I'd rather get it wright, then have a pile of styro foam
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Old Mar 02, 2007, 11:59 PM
Let er Rip
Pilot44's Avatar
Long Island, NY
Joined Oct 2003
3,111 Posts
Stuart,

I answered your PM.

That 4 blade will over amp you big time with that AXI. Go with a 2 blade either Aeronaut 8.5X6 or the APC E 8X6 prop. You will be OK, and be flying half throttle most of the time, which keeps things a bit cooler and longer flight times.

As everyone has suggested, an amp meter is a good tool to have. Saves on motors and ESC's.

The Spit is a great flyer once trimmed out. Good luck mate.

Jim
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Old Mar 03, 2007, 03:32 AM
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Mike Smart's Avatar
Aylesbury, Buckinghamshire, Great Britain (UK)
Joined Jan 2000
3,029 Posts
Anybody any idea on what would be the best motor to run the supplied FSK 4-blade prop?

Mike
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Old Mar 03, 2007, 04:02 AM
Light and floaty does it
Work in Progress's Avatar
Cambridge, Great Britain (UK)
Joined Sep 2004
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Axi 2212/34 on 3S
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Old Mar 03, 2007, 04:02 AM
buy a lot, fly a little!
stuart warne's Avatar
Hong Kong, Hong Kong Island, Central And Western District
Joined May 2001
5,657 Posts
Thanks Pilot 44, hi Mike. I was thinking the same maybe it would just be easier to swap the motor for a different Axi and still retain the scale prop and spinner. Someone suggested to me the Axi 12/20/34, though I don't have the spec sheet with me so I not sure right now why its more suited. I'll ring puffin models and see what John could suggest.
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Old Mar 03, 2007, 04:04 AM
buy a lot, fly a little!
stuart warne's Avatar
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AHHHHHHHH, WIP, you beat me to posting. Hows the 34 better suited than the 20?

Stuart
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Old Mar 03, 2007, 04:05 AM
Light and floaty does it
Work in Progress's Avatar
Cambridge, Great Britain (UK)
Joined Sep 2004
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Stuart

A "smaller" Axi motor will only make matters worse. What you need is a much lower KV rating, and that's a motor which is either cooler wound and/or bigger. The 2212/34 is the easiest swap that will do what you want.
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Old Mar 03, 2007, 04:07 AM
Light and floaty does it
Work in Progress's Avatar
Cambridge, Great Britain (UK)
Joined Sep 2004
2,859 Posts
Your 2212/20 is 1150KV, the /34 is 710KV
Oversimplifying a bit, you can think of the /34 as equivalent to a /20 geared about 1.6:1, albeit with a 10A max rather than a 12A max.
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