1QwkSport2.5r

Spent a little more time on the SI Flatty. Pretty much just the trim around the outer perimeter of the hull and around the base of the engine stand. I'll need to do some more sanding and such, but hopefully it won't be too much more work to finish the boat up.

1QwkSport2.5r

More progress on this thing... It's turning into the 6 month itch at the rate I'm going... . I still need to sand a few pencil marks off the engine stand's uprights, but all the rest of the top has a first coat on it. So far it looks pretty good. I'll weigh the hull this weekend sometime if I get around to it. It's pretty light I think.

1QwkSport2.5r

She's darn close to being done. I put a .46 glow engine (TT Pro) on it for "proof of concept" and will put a diesel on it when the weather warms back up a bit. Still a few screws and zip ties needed, but minus fuel and those few fasteners, she's at 5#14oz. Probably 6# even RTR with fuel. Should be good to go with 7-9# thrust.

1QwkSport2.5r

Okay, it's done. I need to find a graphic to paint onto the engine stand, and I haven't decided if I want an antenna tube and switch in the lid or not... But for now, it's good enough. If I get off work early tomorrow, I'm testing her out. If it runs without blowing apart, I'll take a video. It turned out pretty good.

crispyspa

I love the burl look on the deck. looks cool. You need to get video...regardless if it blow apart or not. LOL

crispyspa

I recently did some body work on a car I bought, I purchased WAY too much clear coat. If you want an automotive quality clear cote on that beast, I'll spray it for you.

1QwkSport2.5r

Oh, I will.. . Should move pretty good. I hope. LoL.

I already have epoxy down (2 coats) and polyurethane on top of that (2 coats). It should be fine, but worst case scenario insane the deck back down and start over. We'll find out what happens.

1QwkSport2.5r

Here's a video of this thing running. The video isn't the best, but it's something. Should move pretty good on water. http://youtu.be/-iJSLPsqEWw

crispyspa

YEAH...that's going to be stupid on water.

1QwkSport2.5r

I'm taking the TT Pro off of it in the next few days and bolting one of the Super Tigre diesels to it. Going from 6.5-7# thrust 10x6 to a 9.5# thrust 13x6. Should be interesting.

1QwkSport2.5r

The Diesel SuperTigre .45 is mounted up. Note the difference in propeller size from glow to diesel. 10x6 to a 13x6.

1QwkSport2.5r

I forgot to add this other video from the other day. Wet snow on grass sorta sucks. It gets stuck to the bottom of the hull and weighs the bow down and causes it to dig in the turns which throws snow on top. A big lip on the front may help, but I don't like how they look that way. I may add one later, but I need more runtime on the boat to decide. Flip at the end of the video, too.
Video: http://youtu.be/Ch7shqlwYg8

Changed the exhaust orientation and added an extension to blow the stinky oil away from the hull. I also mixed up a fresh batch of diesel fuel. Notice how the can is a teeny bit ballooned out? Ether evaporates very quickly and pressurizes the can. You only open diesel fuel cans when you need to. The ether "goes off" quickly.

A video of one of my other diesel conversions running in case anybody viewing this isn't familiar with diesels. http://youtu.be/NmXAJHhjQSA

Pros of diesels: bigger prop turning capability (more thrust) at a lower operating temperature, no glow plugs, no kick backs when hand starting, rarely if ever flames out, lean running will never hurt a diesel unlike a glow engine.
Cons: Generally do not like high rpm, easy to flood (if too "wet", they just won't start), exhaust odor is very pungent - the smell gets in your clothes. Very similar to the smell of a large commercial airport, two adjustment procedures - carburetor needle valves and compression adjustment, very different learning curve compared to glow engines.

Overall, it's not hard to learn diesel. The differences in tuning are easy to "get" once you get some time in it and can hear what the engine is telling you. Tachometers help immensely.

1QwkSport2.5r

Just another photo of the diesel beast... . The ruler is 18" BTW.

arcdude

That turned out great, in the ball diamond it looked like you had great rudder control, excellent build!

1QwkSport2.5r

I need to adjust my throws a little bit - I don't get as much throw turning left as I do right. Some fine tuning and possibly changing control horns will give me the control I want. It does go like mad though. The boat is 6# all-up. The TT .46 glow pushes about 6.5# thrust, but the diesel puts out over 9# thrust because of the prop being 3" longer. It's crazy powerful - enough to scare me a bit to run it on water. It turned out really well considering I only spent about $10 on the build.

arcdude

Can't beat a $10 build! I knew one fellow who had small diesel engines on planes and he loved them, get used to anything I suppose. The difference in turning has been a topic in mind and I've often wondered if some form of diverter wouldn't assist in equalizing it. We all experiment and someday someone will stumble onto something to solve the whole issue.

1QwkSport2.5r

The nice "pros" with diesels - no glow plugs, no flame-outs, idle lower, and make more power. They don't like to rev up as much as typical glow engines and as such need to be propped accordingly. On the same token, a .46 typically would overheat and quit using a big prop like a 13x6, but as a diesel, it will just chug along. The "cons" to diesels (mainly R/C diesels) is the fuel is more expensive, and they don't throttle as well if they cool down. One has to adjust the needle and compression adjustment to account for this. I'm still learning the adjustments, but I have a good handle on it so far. I also make my own fuel for about $6-7/Qt versus pre-mix Davis fuel for $12-15/Qt. The ether is the kicker - it's hard to get in any quantity. I'm using John Deere starting fluid which is mostly ether and some propellant.

My fuel mix is 31% ether, 22% castor oil, 47% Kerosene or Jet A, and 2% Amsoil ignition improver. This mix just fits my 1qt metal acetone cans. (I know it's more than 100%). This works quite well.

1QwkSport2.5r

A little update on this boat. Anyone who builds an SI Tapered Flatty will likely need to engineer some larger rudders to have adequate control on both water and land. I found the boat to run straight quite well with more than ample power with a .45/.46 engine. It just didn't steer for crap. So the following pics show the progression of my experimentation with rudder size with the final photo showing the comparison of the rudders per the plans and the rudders I came up with. If my throttle cable was longer, I could use larger rudders yet although I find this size works well. It now runs on grass very nicely (though very FLAT grass is really important as the hull sized being at a sharper angle tend to dig in turns.).

Norman Castle

I'm in awe of this build and am now wondering how on earth is the hatch secured and made waterproof?

1QwkSport2.5r

I guess I didn't put a picture in the thread about how I mounted and sealed the radio box cover. I used blind T-nuts under the lip of the radio box and thin window sealing foam strips on top of the radio box lip. I made two covers - one from the piece of plywood I cut out and another from thin Lexan.

Got RPM

I like what the OP did with the hatch, but a far easier method is to use hockey tape. I've used it for 20 years on dozens of boats: works great, invisible, cheap and no screwdriver needed.



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1QwkSport2.5r

I've had tape leak after getting wet from flipping the boat, so I stopped using it. I get a positive seal and no worries about the lid from flying off.

Norman Castle

Thank you gentlemen. I'm still trying to find the ultimate combination of low-profile, waterproof and easy on and off but I'm rapidly losing hope of ever getting all three in one ...

1QwkSport2.5r

The easiest and quickest is having the lid flush with the deck like mine and using a good sealing tape. I wouldn't trust tape alone - as I said I've had it leak, so the foam tape between lid and box as insurance and then tape may be the next best thing. The switch in the lid turns the receiver on and off, so unless water gets in or I need to charge the battery, I don't take the lid off.

Got RPM

Wrong tape. Hundreds of us FE racers have used it, we flip all the time. If carefully done, no leaks even flipping at over 90 mph. But if screws and foam make you happy, go for it....


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