Kyosho Spitfire, AXI 4120/18 ??

[chuck322]

I have a Kyosho Spitfire and want to make it Epowered (56"span, 88oz).
Thought about AXI 4120/18, APC 12x6 and 6s2p 10 c (2x 3s parallel) Dymond LiPo.
Gives 9600RPM, 510 W in, 430 W out, 28A, 94oz static, 72oz flying all calculated.
I don't like gearboxes.

What do you think,
Chuck

[Mellemel]

I have the same motor and prop on the KY Tigger moth at 54" and about the same weight, but a lot lot more drag ! it will take off at half throttle after about a 15 metre run and climb. There's more lift though s'pose with the extra wing.
This Axi is too much power for the Moth so I only use full power to do some wild aerobatics kinda limited with this plane though. I only use a 2500Mah 4S 1P Tanic which gives me 12 minutes but this is on half to 3/4 throttle.
You''ll have enough power with that Axi in the Spitfire.
Good Luck with it. :)
Mel.

[chuck322]

Thanks Mel.

[F1 Rocket]

I have a 4120-18 on an Ultra Stick 40. I run a 16x8 APC-E cut down to 14" on 5s-4p TP Pro Lites @ about 900 watts. On 5s-2p the same set up pulls about 800 watts due to voltage drop. I believe you would have plenty of power on 5s unless you are restricted to 12" dia due to clearence.

Danny

[chuck322]

I did some new calculations, because 6s3p is too heavy and expensive for this small plane and it would be 5oz heavier compared to built it with a Saito 82 I already have.

Now:
Airframe empty 60oz
lighter servos: 2x JR 368, 2x JR 3041, 1x Jr 513 (retracts)
Axi 2826/10: 181g instead of 320g for the 4120
Phoenix 60: 58g
Dymond 12C 2100 4s2p total: 340g vs 600g for 6s3p - best thing: only 120,-$ (59,- for each 4s pack)
total weight: 2340g or 82.6oz or 5.16lb before it was 100oz

Motocalc:
APC 13x7, 42.9A, 13.7V, 586 W in, 381 W out, 8063RPM, 75oz thrust at 4500ft, 25°C, 1020hPa.

I think 75oz thrust is enough to fly a 82 oz warbird around.
Will it be enough??
Chuck

[chuck322]

Oh and I forgot,
The Great Electric Motortest at www.flyingmodels.org/index_en.htm states:

APC 13x6.5E at 11.2V, 42.1A, 472W, 7660RPM, and 82.7oz thrust.
Chuck

[kelvin]

Here is my Kyosho Spitfire thread. I use Springair retracts. I hacked the landing gear position which the thread will show.

http://www.rcgroups.com/forums/showthread.php?t=131420

I run my Spit with a Hacker B50 10L, 5.2:1, 14x10 and 5s4p Thunderpower 5300. AUW is 6lbs 3oz with this pack. Due to battery technology improvements over the last couple of years I went from 6lbs 15oz with 16 3000s to 6lbs 3oz with the latest lipos. The way the model flys it is overpowered. I think a 4s with a 4120-14 would work well with a 14x10 if you haven't already purchased a motor. I've seen that motor fly a 7lb Kyosho GeeBee just fine. I'd hang the ESC under the motor to get as much weight forward as possible. You need nose weight in this model to get it to balance. It barely balances with my 5300 pack. My B50 10L with heatsink weighs about 13oz. If I had a B50 13s which is 2 oz lighter it wouldn't balance without adding lead.

Here is a 12mb Quicktime video of my Spit at the Arizona Flight Festival held this past February. I was flying it with a TP 5s3p 6000 pack which weighed 23oz. It was a cold day and the batteries were cold. Flying it with a 5300 pack (19oz) is even better.

Kyosho Spit at AEF (http://kelvin.rchomepage.com/AEF_Spit.mp4)

Keep us informed.

Kelvin