Monday, November 30, 2009

Kep's .21 Freebie V1.09

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! Read the T2 presentation HERE.

UPDATE MAY 2010: The pdf's to this earlier "old" freebie is removed. I have uploaded new drawings for an up to date RACE2010 version of it. Click HERE.

I have updated the original Kep's .21 Freebie PDF drawings to V1.09. The tub is the same as the earlier one so that template is not updated.

- Front sponsons are updated with slightly more built in AoA on the running surfaces. The running surfaces now have no "V" angle either = completely flat if you look from the front (or back). They are also simplified so there are no chine angles and no non-trips either so the complete sponsons are narrower. Its also updated with running surfaces overhangs to the sides of the sponsons. The C-C of the sponson tubes are exactly the same as before.

- The turn-fin location in the sponsons is moved to the front = better handling.

- New turn fin design includes multiple mounting holes.

- New rear sponsons with no non-trip angles - easier to build.

Here's a link to the original and first version of the Kep's .21 Freebie PDF drawings.

Save the pdf's on your favorite movable storage media (such as an USB stick) and go (or send by e-mail) to your local print shop and have them print them at 1:1 size or 100% and they should come out at the right size.

This is the main V1.09 updated pdf drawing including the "old" tub etc. The templates are at the bottom which you just cut off and make templates out of.

If you already have printed out the first version of the PDF main drawings or you may already have built a Kep's .21 Freebie tub - then you only need to have this file printed. It contains the front and rear sponson template profiles and the new turn fin design (all 3 are the same - you may want to make some spare ones!?).

If you only want to make some new turn fins this is a file with only that and a template for a stiffening brace plate. It fits the first version of the Kep's .21 Freebie also.

Have fun building!


Building sponsons with CA part 1

Here's another set of pics and some info that I published a few years back in the gallery section of International Waters forum. The original link is to the right marked as "Kep's 21 build tips #2" or you could just klick here.

As mentioned the pics and texts where done a few years back. The actual design of the sponsons in the pics is pretty similar to the ones in the original Kep's Freebie PDF drawings.

Today I would not build them exactly like this with chine-angles and non-trip angles etc but I hope you find the info and pics somewhat inspiring at least!?

Building is fun! :)

Also read my earlier blog about the glue test.

Couldn't live without them, Great Planes bar sanders - I use almost exclusively 80 grit paper.

Sponson templates made from 1.5 mm plywood. The drawing is glued on with spray cement. Be very careful when cutting them out. Cut them on the inside of the outline. I make my boat drawings in Illustrator.

Template with 1 mm holes for making a punch hole to the plywood sponson insides.

A set of inside parts for 4 pairs of sponsons. Its way easier and faster to do more then one set at a time. The plywood is hold together with pieces of carpet tape.

Divinycell H60 closed cell PVC foam core material. In this case for building a pair of .21 size sponsons. Works very well with normal CA glue if "right" technique is used. When I have tested - CA glue makes a superior glue joint when skinned with plywood vs epoxy glue - on Divinycell H series that is...

4 left and 4 right inside plywood parts after they are "broken" apart. R = 2.5 mm & L = 1.5 mm.

2.5 & 1.5 mm thick.

Another view of the plywood insides. Ready to be CA glued to the foam core.

Use the inside sponson template and make a rough outline on the Divinycell foam. Vacuum the foam or blow the excessive dust away... Spray kicker on the plywood, then spread CA glue on the drawn line all the way around, then fill it in in a zig-zag "pattern" between the lines. Apply the "pre-kicked" plywood (kicker side down!) to the Divinycell. Then turn it upside down and push down. It helps if you have a flat surface of course and some plastic wrap or similar so you wont glue you sponsons to the table...

The CA glue has set.

Maybe I have used too much CA glue... Speaking of glue - I have only tested Great Planes Pro CA medium and slow + ZAP green + slow. They all work the same - no difference what I have seen. The slow/thicker one just isn't needed for how I work. If you're slow working or uncertain how well you will do, try out the slow curing ones. Make sure to add kicker to the plywood part (no glue added there).

After cutting the upper part away in the band saw, use the bar sander to smooth the top surface. Not important at this stage to make it perfect. Use the top view template and make a line for the outside cut.

Before you take it to the band saw again. Sand the outside and keep it at 90 degree measured from the bottom that is 90 degrees from the inside... Right!? When working in the band saw, check that it saws in 90 deg (adjust the baseboard of the saw). Pay attention to making the band saw cut as close as possible to he line and be smooth. The outside back-support wont need any sanding - it will support the ply good anyways...

I make an simple matching line with a pen on the foam. Its way easier to make it right as one doesn't have sooo much time as with epoxy...

After the band saw. Only 2 of these parts is used. The outside and bottom parts are used for support when gluing those plywood parts to the foam core.

The outside is here ready to have its plywood glued in place.

After the band saw. The outside is sanded smooth - the other parts are not sanded yet.

Ready to be glued. The guide line is on the inside of the plywood also - it just makes it easier. Kicker on plywood and CA glue on foam - press it together for about 60 sec. Use a little extra kicker if needed. Use a table fan to remove the glue and kicker odor...! BTW, use some throw-away vinyl protective gloves also.

The CA has set. The cut away foam part is used as back-support. Only hand/body pressure is used. No weights etc.

On this set of sponsons I used 1 mm plywood on the outside. When measured its 1.2 mm though. On the thick side I guess, 0.8 mm isn't a problem.

After the CA glue has set. The plywood isn't trimmed yet...

The top part is sanded smooth and in 90 deg to the inside. This is the guide lines for an chine-cut.

Short depth of field here - oops. The "curved" part here gives itself... Viewed dead on (from the front or back) its completely flat.

Bad picture... Just a view of the angled chine-cut before the plywood is glued. This "version" is perfectly straight and parallel to the inside. One can do them different or not at all... Its all up to you.

Stay tuned for part 2 within a few days...

Saturday, November 28, 2009

Kep's .21 '09 in wood

Here's some pictures of some Kep's .21 ´09 riggers I built last winter. I built some extra boats and later on sold them like they're shown in the pictures to some new boaters in Eksjö. The boats below are exactly the same as the boats me and Mikael Sundgren have raced this season (but he didnt test his '09 until end of the season though).

I built them (last winter) with a rear ski/ramp set-up and I raced my own boat like that for the most part of this years season but for the last race of the season I took it off and mounted some old sponsons and it was way better. So just because you see the pics with the ski-ramp on it doesnt mean I recommend thats set up (on a Kep's rigger).

See THIS blog about my race experiences with the Kep's .21 ´09.

These "stealth" look sponsons are cool but they're a bitch to build... ;) There is no differences in how they work vs the other design you can see if you scroll down a bit...

Mikael Sundgren's rigger with these type of "stealth" sponsons.

Notice the small "hook" I've glued to the bulkhead. They're used as strap mounts to hold down the receiver. We dont use any lid cover for the radio compartment - only adhesive "tape" (it comes on a 2 feet wide roll and is used for covering books etc). So its nice to know the parts are hold down securely.

Here's the hook system for holding the RX battery pack (5xAAA NiMH cells). The hooks are made of K&S brass stips that are 0.8 mm thick (1/4" wide) and equally thick plywood.

Pre-drilled holes for S9650 servos for channel 2 & 3 and for S9551 on the steering. The short rear servo mount is made out of scrap pieces of the same 6 mm thick okumé/gaboon plywood as we use for the tub sides and bulkheads. If you look closely the top part is at 90 deg so the screws doesnt split the wood... ;) The other servo mount rails are normal 8x8 or 8x10 mm spruce.

This is the sponson design I have raced all season with. No chine angles what so ever and it works great. The need of chine-angles are way over rated. The rigger wont trip on these - I promise. :)

My race boat with these sponsons.