First airboat build
 

I've mentioned my scratch built airboat in some other posts, but it wasn't finished until yesterday. I've never worked with foam before and I love it. I put this boat together in a little over a week, but part of that time was waiting for my radio I ordered (Ranger 2n). I'm retired and can work on my projects for several hours each day. This is my airboat build page on my WEB site. As of now, I haven't tested it, so I don't yet know how it will perform. I hope it isn't overpowered to the point where it becomes unstable. the photos below were changed on 7/21/08 after I rebuilt the engine stand and my web site below has been edited as well.

http://web.tampabay.rr.com/wdsummers/airboat.html

RE: First airboat build
 

thats so nice looking, anyone would believe you if you said it runs great!:D if you have a cam, make a vid please.

RE: First airboat build
 

looks nice ! Is that a sheetmetal engine stand ? Paint looks great ! USA !

RE: First airboat build
 

Thanks for the compliments. The engine stand is two pieces of 1/4" lite plywood, one for each side. I cut pieces of 1/2" x 3/4" aluminum angle, bought at Home Depot, to attach the engine to the stand and to mount the stand to the plywood decking. There is a close up of the top of the stand on my WEB page link above. Two 3/4" wide strips of 1/4" balsa were glued to the back of the engine stand to make it easier to insert hinges for the rudders. The paint is from spray cans over the epoxy coating on the foam. I sprayed on the white base coat first, then masked off first the red and and then the blue areas and sprayed them on in that order.

RE: First airboat build
 

WOW looks grate
you have to make an little video of it in action ;)

RE: First airboat build
 

I have the video cam, but no operator. It's hard to control the boat and shoot video at the same time. I wish I had a way to convert it to a helmet cam. Maybe I can figure out a way to put the radio TX and cam on a platform of some type. I'm thinking of trying out the boat sometime today.

RE: First airboat build
 

Attach the camera to the back or bottom of your Radio - with the on/off button in a convenient location - can you say duct tape.

RE: First airboat build
 

I usually come up with something that will work and I think this will do the job. I didn't use duck tape, but instead, a couple of wire ties on the handle through holes to the underside of the plywood and two rubber bands around the rig to finish securing the TX to the plywood. While the cam is flat, the TX is slightly angled upward for a comfortable position. The viewing screen is where I can keep an eye on it to make sure it's level. I'll use a neck strap to hold the rig steady. It's easliy removable to put on my TX for my sailboat to get videos of that as well. I'll try this afternoon if the rain holds off as the winds will be better for sailing.

RE: First airboat build
 

Most Impressive !

RE: First airboat build
 

No video yet. I couldn't get the engine to start. Either the fuel tank is too low (just beneath the engine) or the carb may have been damaged in the crash of the airplane it was in. I can check the first one easy enough. More later...

RE: First airboat build
 

Well, it looks like I'm back to the drawing board. I did have a bad glow plug, but that's not all of the problem. With the fuel tank below the engine, it just won't pull the fuel up and keep running. I can get fuel to the carb, start it, then it flares up and dies as it runs out of fuel. I removed the tank and positioned it on top of the rudders and it runs fine. I don't have enough space to mount it like it is now as it sticks out the back between the rudders so that they won't move. I need to make another engine stand, wider, so that the tank, when centered won't interfere with the rudders. This sucks. But, nobody ever told me that scratch building would be easy. You live and learn

RE: First airboat build
 

Hmm that strange cause most of us run with the fuel tank just under
the motor and a 46 will keep the fuel pressure up
Have you tried a oneway valve on the fuel line ?

Remember if the motor was tuned for airplane running before you need
to tune it for boat running now
As a airboat motor it doesnt unload as airplane does plus we very the
throttle a lot faster & it doest cool as much like it does in the air ;)

Hope these thoughts help

RE: First airboat build
 

Boatman, thanks for the tips. I needed those. I didn't have a valve for the fuel line and that may have worked. Anyway, I've taken the engine stand apart and moved the bottom angle pieces to the other side, using the same holes in the decking, but putting the sides of the stand further apart. I've cut out a 1/4" lite ply engine mount instead of the metal angle pieces I used before. This piece will attach to two 3/4" x 1" x 3" blocks of wood epoxied and screwed to the sides of the engine stand. Ths piece also extends back to the front of the rudders, leaving a platform to strap the tank to, just behind and level with the bottom of the engine mounting flanges.

The engine is an EVO .46 and they don't run as fast as my other engines, just barely turnng over 11K rpms. With the flywheel on them, that makes them slower and steadier for the trainer airplane. I've flown my size 40 seaplane with this engine and it does perform "adequately".

RE: First airboat build
 

The engine stand has been rebuilt with the fuel tank higher, but now, the engine won't start at all. There is fuel coming through as it's spraying out the carb a little and the glow plug is good as I checked it. I don't know what the problem is, but I may have to rob another engine from one of my planes. These are all .46 size and they run better than the EVO did in the first place. It may be another day or two before I'm ready for a test run.

Later...
I finally found out that somehow my carb adjustment was way off...in fact, the needle was closed all the way. I opened it up several turns, got it started and adjusted it to max revs. Was it necessary to raise the fuel tank? Probably not...just a lot of work for nothing. I may stick it back underneath the engine later just to see if it still runs there. That would improve the balance as I now have more weight to the rear (fuel) with it behind the engine rather than beneath it.

RE: First airboat build
 

[link=http://cajungatorairboats.com/v-web/bulletin/bb/viewtopic.php?t=77]This may be of some help[/link] carb 101

RE: First airboat build
 

I did read Carb 101 and yes, that helps clear up how to adjust the low speed needle. I'm fairly new to glow engines and still needed help to get my cargs adjusted properly and this should help me do it right by myself. Thanks for the link.

RE: First airboat build
 

so sounds like well be seeing a video soon

RE: First airboat build
 

Well....I'm still having problems getting either of my two glow engines to run well enough to put it in the water. I haven't been working with them for a few days and need to get back to working with them. As soon as I do get one running and sure it will keep running, I'll get the boat in the water and try to get some video. But, don't hold your breath waiting on me to get it done. :)