RCPowers F1 Hydro 3D Review

Name: F1 Hydro 3D
Distributor: RCPowers.com
Type of product: PDF plan
Suggested material: 6 mm Depron
Airplane type: ParkJet
For: Intermediate to advanced pilots
Flying weight: 280-480 g (10-17 oz)
Length: 787 mm (31”)
Wingspan: With “training wings” 718 mm (28 ¼”) | without 394 mm (15 ½”)
Prop: 6*4 – 8*4
Suggested power system: 2200kV motor | 6*4 prop | 3s 1500mAh Li-Po
Servos: 3 ~9g servos
CG: 87 mm (3 ½”) from where the wing and the fusulage meets (same place as the carbon spar)

Introduction and preparation:
Buying the plan from RCPowers was a breeze. Simply pay via Paypal and your sent a download link via mail thats valid for 1 week.

The next step is to print the PDF. This part is pretty straight forward; press print and make sure that you have 100% scale and just wait for the paper to role out of your printer.
The quality of PDF’s from RCPowers is quite excellent compared to some of the ones found on the forums.
After that its time to tape the papers together in the right order and cut out the templates. I like to make mine out of thin cardboard which makes it easier to transfer the outline to the depron, and makes the templets last much longer.

The build:
Klick here to read the complete build log of this project

I have a trick when cutting depron and that is to sharpen your razor blades on a knife sharpening stone after every 2 or 3 cuts. This way you always get a nice and clean cut and don’t waste tons of razor blades.
One blade can easily last hundreds or even thousands of cuts.

All the parts cut out

The design is quite brilliant in my opinion. Everything feels like it’s been optimized to the extreme and the number of cuts it kept at a minim. I really like the simplicity of the design.

The build was straight forward and the instructions on the RCPowers site was good and easy to follow which left out much of the usual guessing when building.

There is only one thing you have to pay attention to when building, and that is the sponsons. These have to be completely watertight or you will have a short first flight.
But it’s not hard to get them waterproof, use 5 minute epoxy and you will be fine.

When I built this F1 Hydro I chose to evert from the manual at some points, and these were:

  • DU-BRO hinges on the tail rudder instead of tape.
  • Mounted the elevon servos sticking out on the sides rather than inside the fuselage.
  • Mounted the ESC “outside” the fuselage rather than having it on the inside.
  • Added plastic on the sponsons to protect them from wear and tear.

You can see pictures and read more about this in my build-log of this build

When mounting the motor it’s important to make sure the propeller is as close to the wing line as possible and that the prop does not hang down more than ~32 mm (1 ¼”) otherwise it will start to hit the grass or water.

Finished for testing.

The initial power setup:
Motor: Topwerpro 2409-12T 1600kV
ESC: Towerpro 18A
Battery: 2s1000mAh 25-35C Loong-Max
Prop: 8*4 slowfly GWS

Flight testing:

Initially the plan was just to test-drive it around on the ground because the wife had the car so I couldn’t get to a field.
I walked to the nearest place that I could find with some flat ground and plugged in the battery.

The Hydro handles well on the snow and it is a total blast driving a round on the ground, but after a while my fingers got a little to itchy…
I thought that I would take of for just a short bit and land it directly, a little jump with other words.

Well this is how it ended:

Nothing serious. It took about 10 minutes on the bench to get it patched up.

I fitted a 8*4 DD GWS prop instead of a slowfly after the crash.

Here is a video of one of the first flights:

The F1 Hydro 3D is incredible stable in the air! It has no tendencies to tip-stall with the “training wings” and has a wide speed envelope. It has no bad habits that I have found and it’s a real joy to drive around on calm water and flying just above the water. One thing to warn you about thou; While in the air, don’t expect the rudder to act as a rudder on a “normal” plane. The rudder will cause the plane to roll not yaw. This airplane is flown like a delta wing with elevons. If you use the rudder in combination with the elevons you can get some crazy fast rolls or funny looking loops/rolls.

When you drive around in the water you will find that it is very hard to turn at low speed. This is because the sides of the sponsons that run all the way to the back of the plane acts as rudders that keep the plane on a straight course in the water. But once you get up to speed the plane starts to lift itself up out of the water and starts to hydroplane it is very responsive to rudder inputs.

Since the plane does not whey much compared to the surface of the wing it is a little sensitive to wind. I have tried flying in pretty high winds and it is a challenge. It jumps all over the place and it’s not easy to land.
It handles waves quite well but it’s far from as enjoyable as driving around on a dead calm lake.

More flight testing:

Now with over 2 hours in the air I decided to paint it up.

I have also tried out a few other prop/Li-Po combos.
The best by far has been 3s 800mAh Li-Po’s and a 8*4 prop.
This setup draws 16.8A @ 10.9V = 183W
The flight time I get on this setup is 7-8 minutes.

Here is another film that I actually crash in:


The power setup I liked the best:
Motor: Topwerpro 2409-12T 1600kV
ESC: Towerpro 18A
Battery: 3s800mAh 20-30C Loong-Max
Prop: 8*4 DD GWS

All up weight: after painting and with the 3s 800mAh batteries is 287 g.

This is one of the most enjoyable RC airplanes that I have flown!
It has a wide speed envelope, has no bad habits, is stable and predictable.
The build is quite easy and the design is brilliant. Nothing to complain about.
You can drive it on almost any surface which make it a lot more versatile than other flying boats. I relay look forward to the summer when I can take it with me when we to the beach; First swim a while and then fly for a while then eat some cookies and then fly a little bit more.

This PDF plan truly deserves a good grade!

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