Tuesday, December 2, 2008

Kep's 21 Freebie PDF drawing!

Update November 2012: The all new KEP's T2-21 is published - click HERE. The T2 is a more modern, lighter and faster 3.5 cc outrigger hydroplane!

Update (October 2012):  I'm happy to announce that Friday November 2 2012 I will publish a completely new PDF template freebie design - the KEP's T2 .21. So welcome back soon and download the next generation racing outrigger hydroplane freebie!

UPDATE MAY 2010: The pdf's for this earlier "old" freebie is now removed - I have updated the design to 2010-spec now. The basic info here below is still valid though regarding hardware and material list etc. Click HERE for the Kep's .21 RACE2010 drawings.

Update November 30: New V1.09 version.

Update December 4: Additional "Sirio" version PDF, check the links to the right ->

I have had this idea for a while now, to make a freebie template-drawing of my Kep's 21 racing outrigger hydroplane. So here it is.

Download the pdf's on the links to the right ->
(The jpg's here above are for reference only)

The pdf's are only meant to be used as template drawings. They are NOT meant to be a base for your own drawings as they dont include much measurements etc. So don't ask those questions please. If you do plan to make your own version (as in changing dimensions etc) - feel free but dont ask me anything about that... ;)

Download booth pdf's and go to an print shop and print them out on a full size drawing paper in 100% size. Then cut off the lower part of the main drawing and use them when you make your actual templates.

See also the other links to the right for pics and tips on building wooden hydroplane riggers in general. They should include most info of how to build one of these.

Kep's 21 Freebie info
• Tub lenght: 707 mm / height: 44 mm
• Tub outside width: 76 mm / inside width: 64 mm
• Overall lenght: 738 mm
• Hight under belly: 16-17 mm
• Width between front sponsons: 330-350 mm
• Designed only together with 2 x Futaba S9650 & one S9550 or S9551 servos and one 5-cell NiMH AAA reciver pack
• Weight: 1750 g RTR with no fuel
• Use Divinycell H60 for sponsons
• Use 6 mm Okume/Gaboon marine plywood for the tub sides and most of its bulkheads
• I use "cheap" 8x10 mm carbonfibre tubes and solid 8 mm carbon rods for the sponsons
• Use CMD 21 size engine mounts or make your own, messurements are included in the extras file
• Use a CMD drive line, including flex, strut, rudder etc.
• I will do a "complete" shopping list a little later...

Update December 3: The PDF's are updated to V1.01 now. Cooling tube views are also included. Oops.

Update December 4: I have uploaded an additional main Kep's 21 drawing if you want to see how it looks when U use an engine with 180 deg exhaust also. Use the the other main PDF for the templates etc.

Update March 16 2009: If you dont want to build any rear sponsons on your Freebie - click HERE for more information. I have also added a shopping list. Ps, the PDF drawings have been downloaded more then 300 times now... :)

Metals etc:

- K&S #1149 (old #149) 1/4" brass tube (3ft)
- K&S #132 9/32" brass tube (1ft)
- K&S #1145 (old #145) 1/8" brass tube for tank & cooling water through the radio room (3ft). For the tank you need to anheal it to make the bends.
- Harris Stay-Clean liquid soldering flux or similar
- 60% lead / 40% tin solder
- 0.2 mm thick tin-sheet metal or stainless sheet for making the tank

- 8 x 10 mm carbon tubes, 325-345 mm long each (2)
- 8 mm solid carbon rods for sponsons, 90 mm long each (4)
- 8 mm solid carbon rods for where you bolt the sponson tubes in the hull, 100 mm long (2). You can use some hardwood dowels also, even make some nice ones in aluminum.

Sponson foam:
- Divinycell H60 or H80 - W: 60 (2.36") x H: 45-50 (1.77-2") x L: 360 (14") mm blocks for front sponsons (2) (or Airex C70.55 or C70.75)
- Divinycell H80 or H60 - W: 25 (1") x H: 45 (1.77) x L: 210 (8.3") mm blocks for rear sponsons (2) (or Airex C70.55 or C70.75)


- 1-1.5 mm (1/16) airplane plywood (for templates)
- 6 mm (1/4) okoume/gaboon marine plywood for the tub/hull sides and bulkheads
- 2.5 mm (3/32) airplane plywood for the right hand front sponson inside
- 1.5 mm (1/16) airplane plywood for the left hand front sponson inside
- 1.5 mm (1/16) airplane plywood for front sponson ride pad
- 1.5 mm (1/16) airplane plywood for front sponson top
- 1-1.2 mm (0.04-0.047") airplane plywood for planking the front sponsons except the top
- 0.8 mm (1/32) airplane plywood for top deck of hull/tub
- 0.8 mm (1/32) airplane plywood for planking the rear sponsons
- 12 x 5 mm (1/2 x 3/16) hardwood spruce for under the sponson tubes in hull
- Hardwood spruce for hull nose block and sponson leading edge
- 1.5 mm (1/16) airplane plywood for the hull/tub bottom
- 2 x 4 mm spruce for engine cowl rest in engine bay - you can make it of excess cut-away material from the tub sides also
- 0.8 mm (1/32) carbon fiber sheet for for gluing on the outside and inside of the transom
- 2 mm (3/32) lite-ply for small reinforcements on the bottom side of the top deck

- 1.6 x 100 x 100 mm (0.062 x 3.8 x 3.8") 7075-T6 aluminium for making the turn fin
(If you dont want to make your own, buy one from CMD. Its not 100% the same but it works.)
- 8 x 10 mm tube for the rubber belows for the servo rods etc (you only need about 40 mm)
- 90 deg angle stock for making the small 3:rd channel needle mount

CMD shopping list:
- Eagle 21-size turnfin (if you dont want to make your own) - cut 1/4" off the trailing edge (if you dont know what I mean I can make a drawing that explains it)
- 3:rd channel fuel valve Kalistratov - fine threaded
- CNC 21-size motor mount system including rubbers, 1/4-20 nylon bolts & nylon washers
- 1 set (3 pcs) – 21 size turn fin aluminium inserts with stainless 4-40 screws
- 0.9" x 4.4" 21-size rudder assembly
– Bullet nosed 3/16” stainless drive dog
– 3/16" x 24” flex shaft
– 3/16” Shaft bushing
– 3/16" propeller nut
– 1/4"-28 flex drive collet for CMB Valvola (if thats what you will use)
– 21-size anti-walk strut assembly

If you want to make your own motor mount rails then you need to buy these instead of the complete system from CMD:
- 4 pcs 1/4-20 nylon "wing bolts" - from CMD, Great Planes, Du-Bro, Fastener-Express etc...
- 4 pcs rubber grommets from CMD or McMaster Carr (9307K39)
- 1/4 nylon washers
- 1/4 x 1/2 bar stock aluminum
- 1/4-20 & 4-40 taps for the motor mounts (you can use a M3 also but you'll get less side adjustment then)

- Center-pointed wood drill bits. 6, 10 & 11 mm.
- Also some others drill-bits for mounting rudder, drilling for water tube etc, etc...

- You need to make your own Cowl or buy one that fits or run without one...
- Starting belt 15" - Aquacraft AQUB9530
- CMB Valvola or your favorite choice of 3.5 cc marine engine

- Aquacraft GrimRacer radio box seal boot #AQUB9503 (2 sets)
- Du-Bro #369 4/40 x 2/56 ball link for steering servo (the ball link for the rudder is included with the CMD rudder)
- Du-Bro #367 Swivel ball link 2/56 x 2/56 for throttle arm (1)
- Du-Bro #336 Threaded steel coupler 4-40 (1)
- Du-Bro #172 (or #801 - 6 pack or one #173) .072 x 2/56 threaded linkage rod for throttle and 3:rd channel - for the 3:d cannel needle I dont use any linkages though, I cut the threaded part off and use Z-bends at booth ends (2)
- Du-Bro #144 Threaded linkage .093 x 4-40 rod for steering (1)
- Du-Bro #893 servo mounting screws (1 set)

- Aquacraft 44x66L propeller #AQUB9765 - if you have never run a hydro before this is a good prop. If you have a high performance motor (low squish with 60% nitro) it doesnt load the engine enough so the motor doesnt perform its best. Its very easy when launching etc. Very similar to a stock ABC H4 prop.

- Aquacraft 45x68L propeller #AQUB9768 - works good as it is for breaking in the engine or the first time you run the boat. No additional cup is needed to start with. Very similar to a stock ABC H5 prop.

- Octura 1445 with 3.2-3.6 cup. Prepared either by either Mark Sholund (Props 4 you) or Andy Brown (CMD).

- ABC H6 with 3.4-3.6 cup. Haven't tested these yet myself though.

Radio stuff:
- In the plans are two Futaba S9650 for throttle and 3:rd channel needle and one Futaba S9550 for steering. If you choose some other servos feel free to alter the radio mounting to suite your needs...
- 5-cell AAA receiver pack assembled in 3+2 configuration.

- ZAP-A-Gap CA glue (green label) 1 oz bottles (2 or 3). You can use other brands also but thats what I use.
- CA kicker. I use Great Planes #GPMR6034 but you can use your favorite brand.
- 5 min epoxy. For small things like gluing in the tubes for the rubber bellows in the bulkheads etc.
- Z-Poxy Finishing Resin #PT40. For impregnating all wood surfaces before painting.

Clearcoat / paint:
- Sikkens Autoclear Plus HS 2K clear and matching hardener + thinner is what I use. I use also spraycan white basecoat and 1K House of Kolor fluo paint that I apply with an airgun.

- You must use a really good 2-component (2K) paint or clear coat system that can withstand the high-nitro content in the fuel.

Have fun building!

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