Author Topic: Airboats (Read 594 times)

Chairboy · « **on:** July 26, 2006, 11:28:20 PM »

Howdy! A friend of mine wants to build a one person airboat. He is.... unencumbered by planning, but he's enthusiastic. I'm doing what I can to keep him from, well, dying. I've been improving his design, researching other designs to figure out the right way to do things, etc.

I'm trying to work out the engine situation right now. He's looking for something lightweight in the 30-40hp range. I've been trying to sell him on a Corvair engine (for obvious reasons), but I take it it's a bit heavier than he wants. Of course, he's also a big fan of the Subarus, I'd guess something like the EA-81.

It's more hp, but better to have a little more than too little....

I think I've almost gotten it into his head how important having a redrive of some sort to put the HP into the right rev range, so we'll have to figure something out for that.

Anyone ever do anything like this? It's really not my bag, but I want to keep him from killing himself. His original design was to be 1/4" plywood, 6' wide, with two reinforcement ribs. I've gotten him to 1/2" minimum exterior plywood, reinforcement stringers every foot on the floor, and ribs to match.

TPIguy · « **Reply #1 on:** July 27, 2006, 08:32:14 AM »

I'm no expert, but I've never seen a plywood airboat. All the ones I've seen were aluminum. They all were running V8's but they were much larger than a 1 man boat.

As for the motor you might look into a 1.3l suzuki motor (samurai, swift.) They are about 60hp and weigh about 175-200lbs. The older ones are carbed so it would be an easy setup.

Goomba · « **Reply #2 on:** July 27, 2006, 08:47:35 AM »

Check out Glen-L.com for excellent amateur boat building plans and supplies.

Plan #400 is a plywood hulled airboat and all necessary building details.

I'd suggest this route, because at least you have a) proven, tested design b) plans and specs c) building support and advice

They provide good, full-size plans...no layup required.

If you want to keep your bud from killing himself, get him to start with a proven design, for safety's sake.

Luck!

Jackal1 · « **Reply #3 on:** July 27, 2006, 08:56:27 AM »

Golfer · « **Reply #4 on:** July 27, 2006, 10:01:43 AM »

So you're helping your buddy prolong his life by advising him against a 40hp airboat of his own design...

yet you want to build an airplane out of cloth and glue...

powered with an automobile engine not designed for aircraft use...

disregarding all the shortcomings of why that's a bad thing...

after flying a tailwheel airplane without the first thought at instruction...

dismissing anything said to help you as someone who doesn't share your grand vision of the experimental universe...

...

...

...

...

I need to go take an advil after smashing my head into the desk.

And...it's a boat. I've built boats out of spare junk wood and skids. Let the man have his boat he won't be crab fishing in the darn thing. You demand the same from everyone else regarding your airplane and other visions and (good?) ideas.

It's your life...it's his life and we're not each others mothers. You need to be more careful than him though...I dont want to read about someone else i 'know' in an NTSB report.

dinghy · « **Reply #5 on:** July 27, 2006, 10:32:36 AM »

where will he run this airboat? if he's planning on running it in the everglades an O-540 or O-550 may be the way to go. the V8 automotive engines are ok and you can run regular auto gas in them but you need to reduce the rpms to around 2600 at the prop to keep the tips from going supersonic, a problem you don't have with the mighty aero engines. Also the smaller engined boats just don't provide the thrust to push you through the high sawgrass during hunting season. the most popular boats are aluminum with a teflon bottom or the plastic boats. I don't believe I've ever seen a wooden boat, I suspect weight would become an issue. most of the boats are still homebuilt around here. I have been involved in the building of two boats. for the hull construction all you need are some basic metal working tools and skills, there just isn't that much to building an airboat. The engines can be purchased from aero engine shops which can usually point you to a plane owner with a timed out engine and can be purchased for around the price of the core. the engine may not be good for airplane use any more but it's plenty good for a boat.

AquaShrimp · « **Reply #6 on:** July 27, 2006, 10:39:45 AM »

Quote

yet you want to build an airplane out of cloth and glue...

powered with an automobile engine not designed for aircraft use...

About 10 years ago a guy did the same thing. On his first flight, he took off, and while climbing out, the fuel system stopped feeding the engine. He then proceeded to crash and die.

Are aircraft engines really that much more expensive than automobile engines?

Maybe I'm just biased (with knowledge). My father was in the civil air patrol for many years, and his main job was to find crashed single and twin engined aircraft. Boy did they find alot, pilot error and engine failure being the main cause of crashes.

Chairboy · « **Reply #7 on:** July 28, 2006, 10:08:59 AM »

Quote

Originally posted by Golfer
after flying a tailwheel airplane without the first thought at instruction...

Is the view from your tower nice? Look, I fessed up my mistake, can you give me some idea how long I can expect you to keep rubbing my nose in it? Thanks!

Regarding fiberglass aircraft, why do you think they are inherently unsafe? And how does that relate to airboats?

Golfer · « **Reply #8 on:** July 28, 2006, 10:37:17 AM »

That's something you're probably never going to live down. Not because I don't care about what happens to you either. I don't sit back and cheer if experimental airplanes crash. I get upset. Same as I do when a rich unqualified guy buries in his warbird. Nowadays due to insurance more than anything else (another industry I don't like...mostly because I worked in it) they are forced to either have a properly qualified pilot fly them or learn from said pilot for a period of time the insurance company sees suitable that they won't be paying on the airplane.

At any rate it's not that you made the mistake that irked me. It's just that everything you disregarded as far as good sense to give yourself the opportunity to kill yourself that really got to me. Color yourself lucky you got out without a scratch, which I hope and am rather sure you do.

As far as fiberglass and composite airplanes...nothing. I was just simplifying things down to what they are. Where I also found (twisted?) humor was after your blatant disregard for your own life foregoing common sense you're playing guardian for your friend because of his boat.

Let the man have his boat. Build it however he wants, make his own mistakes and enjoy it. His life and his freedom. You yourself demand the same with your kitplane and flying certificate.

That's all

Chairboy · « **Reply #9 on:** July 28, 2006, 10:54:40 AM »

Quote

Originally posted by Golfer
At any rate it's not that you made the mistake that irked me. It's just that everything you disregarded as far as good sense to give yourself the opportunity to kill yourself that really got to me.

Translation: That I didn't listen to YOU. Gotcha. Well, it's your perogative if you want to keep grinding away at me for it. If it makes you feel good, go for it, but I'll eventually file you in the bozo bin.

Quote

Originally posted by Golfer
As far as fiberglass and composite airplanes...nothing.

Then why did you use that as an example? Anyone who reads your original post is left with the indelible impression that Golfer thinks that people who build fiberglass planes are idiots.

With respect, if you are unable to seperate your distaste of experimental aircraft from your experience and advice as a pilot, you'll lose your audience. If you really want to keep folks safe, you've got to make an adjustment. If your actual goal is to posture and strut back and forth, then by all means, continue as is. I'll assume the latter is _not_ your intention, and hope that this message finds you well.

Golfer · « **Reply #10 on:** July 28, 2006, 12:49:20 PM »

No not me. I might stand against putting an auto engine on an airplane but that's only with my airplane. Anyone else is free to do as they wish.

My point was that a composite airplane is simply cloth and glue...that's the limit. Nothing hidden, no innuendo...nada.

If you would have asked "is it smart to fly a tailwheel airplane with no experience/training/idea" then my answer would have been no. You didn't, and frankly I was amazed at the judgement call you made by doing it. I had no input nor would I expect to.

The theory of experimental aircraft is great...but the problem is you get folks who are good pilots and poor designers or vise versa and that leads to problems. More risk than reward in my book, but that's my book.

Bronk · « **Reply #11 on:** July 28, 2006, 12:54:41 PM »

Quote

Originally posted by Golfer

My point was that a composite airplane is simply cloth and glue...that's the limit. Nothing hidden, no innuendo...nada.

Would you say wood and glue be better materials?

Bronk

Golfer · « **Reply #12 on:** July 28, 2006, 12:59:43 PM »

I prefer chewing gum, duct tape and twine.

Bronk · « **Reply #13 on:** July 28, 2006, 01:02:16 PM »

I'm just wondering golfer as the mossie seemed to do quite well being a wood, glue and screw construction.

Bronk

Golfer · « **Reply #14 on:** July 28, 2006, 03:25:25 PM »

Bronk I think you missed the point. I wasn't knocking aircraft construction.