I have updated the Kep's 21 PDF drawing to "2010" spec now. The base for this latest version of my Kep's .21 design is based on the boats me and Mikael Sundgren has raced in 2009. But do note, I have included some features on the new PDF that we have not actually used on our boats (yet) but we would build it like this if we would build a new boat right now...
Some of these features (not used by us so far) are:
1. The turnfin mount is finally changed from the 3-hole pattern that is originally from the Eagle SG .21. I made them like that because it was easier to get hold of an Eagle turn fin but that seems not exactly the case today... The new mount is way better with 4 mounts in the sponson and multiple holes in the turn fin to allow for a broad adjustment front to back.
2. The turn fin itself is also changed due to the fact that it now can be mounted further to the front.
3. Up until now I have also made my front sponsons with a pointy trailing edge but I think it will look better with a cut-off look instead.
No more "freebie" design - this is the race boat!
The original Kep's "freebie" I published in 2008 (downloaded more then 1000 times) was at that time an earlier design I had used... But I raced an slightly different version myself due to the fact I wanted the "freebie" to be tested etc. Most of the time here also the season is so short so when I have a design that I have tested and raced with it all becomes "last" years design so to speak. But the Kep's .21 RACE2010 rigger is actually a mix of the boat I race with myself including a couple of features that I have yet to put into my boat. This is up until today the best .21 rigger design I can publish as its the closest to my own 2010 race boat(s).
Here are some basic Kep's .21 RACE2010 specs:
After plane length: 530 mm (from rear tip of rear sponsons to trailing edge on front sponsons)
Sponson inside-to-inside width: 365 mm
Tub belly height (under motor): 17 mm
Tub inside width: 74 mm
Tub outside width: 86 mm
Tub sides height: 44 mm
Tub length: 707 mm
Total length: 749 mm (excluding strut and rudder)
Total width front sponsons: 43 mm (including 1 mm overhangs)
Front sponsons AoA: 3.5 deg
Rear sponsons AoA: 1.5 deg
Tank volume: aprox 250 ml
Motor axis: 5 mm off-set to the right
RTR weight (if you build it like me) aprox: 1750 gr
As my earlier Kep's boats the RACE2010 is prepared for the CMD engine mount bolt spacing and if you can get hold of them, the CMD hardware in general is among the best also.
As with most "engine-forward-with-exposed-running-gear-and-rear-sponsons" 21-sized rigger designs - the rear end needs to be quite light! You need to pay attention to not using heavy hardware and make the hardware you choose to use as light as possible also, especially the items that are the most rearwards... Use light servos, 5-cell hump-style AAA battery pack and in general - build it light!
As you can see I have designed it around the MAC .21 / CMB .21 Valvola type of in-line engine. If you want to you can of course use an car-engine based marine motor with a 180 deg header. The boat will work equally good of course. But as I like to build my boats quite tight (I dont like to waste space etc) this boat is not really that well suitable for the new CMB .21 VAC engine. See further down the page for and closer look on how tight it will be with that motor...
Kep's .21 RACE2010 info:
http://ne-stuff.blogspot.com/2010/05/keps-21-race-2010-outrigger.html
Happy building!
/Niklas
