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Vought OS2U-3 Kingfisher - Mini A-Pack


Building Fool-Flying Noob
During Family Day Trip to Wilmington, NC with my Mother, Step-Father and Sons, we stopped in to U.S.S. North Carolina. a WWII Battleship. Something I had passed EVERY time I went to Wilmington over the years living in NC. As the morning was cloudy and a bit rainy, it was a perfect way to spend a morning. (with the snake museum - Large collection of Crazy-deadly snakes) during the wet time to follow. I came around the rear gun turret to find to my immense surprise and delight a PLANE!
As I learned all about this craft, I learned it was the Vought OS2U - Kingfisher. A trainer-looking water craft sitting on the end of the rear deck.
IMG_20170804_133030062.jpg IMG_20170804_133240035.jpg IMG_20170804_133231329.jpg IMG_20170804_133400793.jpg IMG_20170804_131258889.jpg (these are personal pictures from the trip.)
This whole thing fascinated me. I needed to know the How's and Why's of it!

Why: It slices, it dices, it juliennes fries
I found out (if you read the plaques) the craft was used for many roles during service. It was used for the mail, communications, AA artillery gun practice (see left of the left wing in the first pic), and most importantly Scouting missions, to see what they were coming onto. There is also a whole discussion on the landing techniques for the craft. the plane would signal in and the battleship would build a wake-runway in the water then swing around to the port for retrieval through a special skid and crane.
4562 OS2U.jpg
Above- Using the retrieval crane to mount the plane onto the Launch catapult.

How: Up, up and away
So now we understand how critical the Kingfisher's role was on the Battleships, The biggest challenge they faced was to safely launch this without a runway.
The short is - they used a powder actuated catapult. The pilots would angle into the wind, rev up the engine. and on "go", would cause a powder charge to explode and send the plane off the short length over the side. 0-70 mph (0-112 kph) in 68 feet (~20m). WOW - So Cool!

After that trip I was looking around, and I found a Sim Model (RF 7.5) and tried it. It Flew SO light and floaty. Just a relaxing joy to buzz around in on the sim. Also fun to practice water landings with! Since that point I've been wanting to design this up, build and fly it.

Historical Plans:
1532_045_22.gif vought_os2u1_3v.jpg
Real Pictures:
vought_kingfisher_3.jpg 2009-12393.jpg 3_6.jpg

Project Goals:
  1. Based on some talk here about building a 1:40th scale aircraft Carrier to land and launch planes from, I wanted to build a ~13.5" wingspan, yard-sized bird that would fit on that scale Battleship.
  2. I wanted to double it to 30" for a C-pack size, to enjoy the fun I had in the sim in real life.
  3. Build a scale sized powder actuated Launch Catapult!
Real - Life Plane Operational Parameters:
General characteristics



R/C Operational Parameters:
  • Length: 13.5 in (34.2 cm)
  • Wingspan: 14.4" (36.6 cm)
  • Height: 6 in (16 cm)
  • Wing area: 44 in² (284 cm²)
  • Base weight: 5.3 oz. (150g)
  • Est. AUW: 7oz. (190g)
  • Motor: 1806, 2300kv / 1104, 7500kv (18g/ 6g)
  • Battery: 550 mAh 2S, 7.4V (36g)
  • Propeller: 3023x3 (5g)
  • ESC: 12a / 6A (9g / 5.5g)
  • Servos: - 2-4 5g (20g)
ALPHA build plans and Build
Alpha Build Plans
PDF Capture.PNG
Alpha Build without electronics:

Come and Build one with me and let me know how it goes, as feedback is always a gift!


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Building Fool-Flying Noob
A number of Refinements have yet to be included.
Side note - 5g servos are much more expensive (2.5x) and thereby I have not stocked up. in my mind this is 3- 5g servos, setup like the baby bloody baron.
The plans don't include the Cowl (which they will)
I also have not left holes for the servos, the electronics hatch nor a receiver.
Also it has clearance for a 3" prop or less. I think the gremlin quad 1104 motors or 1106 motors might be best
it doesn't include the rudder on the float either (I plan to make from Gift Card plastic one as part)
I will update as I go


Skill Collector
Something about the front end with the little hole in the windshield makes me think of a cyclops sticking it's tongue out :p

I know people often have challenges getting planes this small to fly well using DTFB - it tends to be a bit heavy and non-aerodynamic at this scale. I've only had one success but we didn't have 1104 and 1006 quad motors back then - those pack a lot more power at lower weight than what I could find cheaply three years ago :D

One other thought when working at this scale is to round off the square edge of the tail surfaces so they operate with less turbulence - sanding or squishing with a hot iron could help there.


Well-known member
I've always wanted an RC Kingfisher. I'm big on float planes in general, and I've always wanted to try my hand at the single float type. The 13.5" size is a little small for me, as most of my models are 36" or larger. Once you scale it up I'd be happy to build an alpha model. Following.


Building Fool-Flying Noob
This project has been on hold until i could electrify it. Thanks for the Tip @rockyboy for working with this scale. I planned to skewer the front of the empennage.

I fully intend on scaling this up @Arcfyre.
For the Traditional Park flyer scale, ultimately I was thinking C-pack, with a 10" slow fly prop. keep watching, the scale up will be coming.
As for now, this project is limited to Stupid small.

guess what came in?

come on... Guess.

That's right, 20 - 3.7g micro SERVOS! Micro projects ahoy! I found them for ~$2 (they may end up being worth more with duds. but it means I can experiment.)