Sunday, February 21, 2016

KEP's FE-4S (P-Open) Freebie




Freebie drawing of a KEP's FE-4S P-Open 4-cell LiPo Brushless in-runner Outrigger Electric Hydroplane.

Note, the KEP's FE-4S is a P-Open 4 cell LiPo outrigger. The boat can be fitted with brushless in-runner marine motors with physical dimensions of 36 or 40 mm diameter that are 65-74 mm long (note, it's physically possible to actually use motors up to 80 mm long but at those lengths it gets more difficult to make a nice cowling and the clearance towards the rear sponson tube is less "wrench friendly").

There is also an slightly smaller freebie version available for the P-Limited class they run in the US (with Aquacraft 3650-2030KV motors). That boat is called KEP's FE-4SL - click HERE for info and download of that. But if you just want to build one of these I recommend building this one as it also works with the smaller P-Limited Aquacraft motor.

Note, if you plan to go fast - let's say above 100-110 km/h - then you need LOT's of water cooling to stay below 90°C on the ESC. Use at least 4 mm tubes in the tub and matching large silicone tubes. Make an efficient and short cooling loop so the water will flow as much, and easy, as possible. It might be needed also to add a second water pick-up to cool the motor separately.

If you want some inspiration for building your own KEP's FE-4S rigger - Click Here (lot's of build pictures)

Specs:
  • Made for 36x65-74 mm and 40x65-74 mm motors
  • Tub Length: 689 mm (27.126")
  • Total Length, from transom to sponson tips: 754 mm (29.69")
  • Tub Width: 84 mm (3.31")
  • Tub Height: 51 mm (2")
  • After Plane: 537 mm (21.14")
  • Sponson Length: 442 mm (17.4")  
  • Sponson Width: 23 mm (.09")
  • Sponson Ride-Pad Width: 30 mm (1.18")
  • Sponson AoA: 3.9°
  • Ski Width: 30 mm (1.18")
  • Ski AoA: 1.4°


Main drawing of the KEP's FE-4S (1of2). Download it HERE. The PDF size is A1 = 841x594 mm. When you have had this printed out in 100% size you will cut the lower part away to make the actual templates etc. NOTE, the "1of2" PDF's is updated 2017-06-30.

Complementary drawing of the KEP's FE-4S (2of2). Download it HERE. The PDF size is A1 = 841x594 mm. This one includes some extra info, extra measurements and some set-up tips etc.

Click HERE if you want to CNC cut it. It's a zip file of the tub sides, sponson sides, ski sides, ski run-pads and all the bulkheads.

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