FT Sea Otter Build

by FliteTest | May 18, 2016 | (16) Posted in How To


New to the R/C hobby?
Here's some resources to help get you up to speed!

Beginner Series: WATCH HERE!
Electronics Setup: WATCH HERE!
First Flight Quick Tips: WATCH HERE!

Got glue?? Get Some Here! 




  • WEIGHT WITHOUT BATTERY: 15.1oz (428 g) 
  • CENTER OF GRAVITY: 2.75” (70 mm) from leading edge of wing 
  • CONTROL SURFACE THROWS: 12˚-16˚ deflection - Expo 30% 
  • WINGSPAN: 40 inches (1016 mm) 
  • RECOMMENDED MOTOR: Motor-EMAX CF2822 (Power Pack B) 
  • RECOMMENDED PROP: 8 x 4.5 slow fly 
  • RECOMMENDED ESC: 18 - 30 amp minimum 
  • RECOMMENDED BATTERY: 2250mAh 3s 35c Lipo Battery
  • RECOMMENDED SERVOS: (4) 9 gram servos 

The FT Sea Otter flies great in the air and looks great on the water. It was created with a simpler design for a better introductory sea plane experience.

The Sea Otter is built with Water-Resistant Foam Board and flies best in calm conditions.

Start by building the fuselage and tail section.

Assemble the wing and wing pontoon.

The motor pod on the Sea Otter is mounted higher to help with throttle management.

Assemble the canopy and reinforcements, and attach them to the your build. This will help keep the plane stable when taking off and landing.

Connect and install your electronics. Be sure to waterproof your electronics before installing them so you have a better flying experience. Check out our Waterproofing Electronics episode for helpful tips!

Check your CG and make adjustments as needed, then take it out for a maiden!

Happy flying!


Dave.E on May 20, 2016
Worked on building this last night, going together really nice. I love how you hid the wires down the hollow tail assembly.

Small problem with the plans: In the video you reference 2 dots that help you line up the tail section and another two on the motor assembly. Those are missing from the plans. Do you have any guidance on how the tail should be aligned without those as reference? (Not so worried about the motor, that doesn't seem to need the dots).
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mickydee on June 2, 2016
Good job Peter
The kit went together with no issues. I used a Suppo 2217/6 motor and the verticals are breath taking
The CG with a 2200 3 cell was 2" aft of leading edge. Ground handling on grass was down right fun. You can do donuts and touch and go all day. very stable with no trim needed for first flight.
Handles 8 to 10 mph wind easily.
This new foamboard takes a little getting used to. I tried several paints and settled on Krylon Colormaster. it dries well and covers good.
All in all this is a great plane. Very rugged and easy to fly. All
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Shreyansh on December 27, 2016
can i make it of cardboard

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LordVader on May 18, 2016
This is really cool. Wish I had a lake or a pond near by to fly this at. Keep it up guys, this is an awesome community and hobby.
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matjey on May 23, 2016
I believe this plane can also be use without the lake. It can land on grass with it large belly. Don't you think so?
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LordVader on May 23, 2016
Yes, I think so, maybe just remove the wing booms so they don't rip off on landing.
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Dave.E on May 31, 2016
I flew mine this weekend: hand launched, then belly landed it. I protected the belly with packing tape so it wouldn't scuff the paint, worked great. The plane can fly so slow and gentle that there's no concern about breaking off the booms.
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letsgofast11 on May 21, 2016
You should build a plane which as its body and wings and tail are completely made of cellophane and zip ties!
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Dave.E on May 31, 2016
Some pictures of my build: https://goo.gl/photos/9zoVVp1SD5JfvWsr9

My kids saw a similarity with the plane in the Miyazaki film "Porco Rosso", so I painted it that way and made a cutout of Porco to fly it. Flew it this weekend at my field,and it handled really nicely. Haven't gotten to water yet, but can't wait!
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WarpedWings on May 27, 2016
Peter, you are amazing with your designs and enthusiasm. I love the Otter and in the process of completing the model. During the assembly of the tail section, you mentioned placing the wire in the middle hole on the elevator for intermediate and the outer hole for maximum movement. Also you said to place the wire in the outer hole for maximum throw on the rudder. I think this should be reverse of what you said. It should be outer hole for the elevator and middle hole for the rudder. Minor point and will work, but will not give maximum throw for the rudder.
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timbacct on November 2, 2016
I have built this plane (out of a kit from Graupner in Europe) and love it. What a great design. Shame Peter has had to move on. One thing I came up with was a mounting method for the solid canopy. I just pushed two skewers into the front of the canopy and made two holes in the "dashboard" and the canopy sits in snuggly. At the back I have glued a bit of foam under the roof of the cabin that the canopy lands on and pushed a skewer through the canopy and the piece of foam. It doesn't really need the back fixing but better safe than sorry.

Thanks for the great designs and inspiration!
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TurtlesThatFly on May 19, 2016
can I also build this with normal foam board?
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Dave.E on May 20, 2016
You can, but you may have troubles with the paper de-laminating if you use in the water. There's another FT video on how to waterproof your plane, but that was more for a little rain not submersion (and the technique didn't get the inside of the plane).

I think this plane would work well in snow, and you wouldn't need it completely waterproof for that.

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Talsharf on June 2, 2016
Great job Peter and the team
I am trying to build my own design of a water plane and that design gave me a lot of ideas so several problems I ran into. Especially the placement of the motor attached to the fuselage and not to the tail wing, like in the Skipper / Polaris.
One suggestion: why not using a solid pontoons, that acts as floats, in order to increase the plane's resistance to flipping over by side wind? They can be placed also a bit far on the wings, so they will have even greater momentum. This idea was working very nice in the episode on the Aqucat and Polaris (http://flitetest.com/articles/modelaero-showcase).
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Aeropiff on May 19, 2016
NICE...looks awesome, great job Peter for amazing us with your plane skills. I'm just gonna ask...was that Chads cutters haha
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Aeropiff on May 19, 2016
Also, can you guys have an episode about motor placing and thrust angles because i was trying to make my own sea plane just like the FT Otter but it kept on tipping down and there was no pitch authority...so yeah THANKS
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Ron DuBray on May 20, 2016
Why did you not run the engine power wires into the pod and down the pod support, ether taped to the back side or inside it??

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Richb77 on February 1, 2018
The plans pages are down (tiled, full and all-in.one)
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FT Sea Otter Build