Home made air motor, questions.

[Overkiller]

My boss wants/ needs a shallow water boat and has been slowly selling himself on the idea of one of those fancy flounder boats. For some silly reason he thinks a new roof on his house is more important then a second boat. Well as a friend I feel it's my duty to help him to his senses. I figure if I rig up an air motor he'll be left with no option but to buy a boat to hang it on. I was kicking stuff around in the plant the other day and came across what I hope is the makings of an air motor. Having never built one I was hoping someone could give me pointers to building a good working air motor instead of whirling blades of death and destruction.

We had an old pressure washer laying around with a shot pump. The motor is a 5hp Honda and after some fresh gas and tlc it fires right up and sounds perfect. Some further digging revealed an old fan we had to remove because it was a safety hazard. Yes a fan mounted to the ceiling providing fresh air in the Texas heat to our workers was unsafe. If one of them had accidentally gotten a ladder and accidentally climbed 12 feet up in the air they could have accidentally stuck their tallywhacker into it. So now if sits unused but it does have a sturdy looking fan blade and I know it moved some air. The fan is 34" in diameter and it wouldn't be too hard to hook up to the little honda motor. The motor driving the fan is a 1hp and with the pulley set up it turns the fan about 600 rpm. Would this setup work for pushing a jon boat through the flats? Also would the motor have enough leftover oomph for a small alternator? Any wisdom would be appreciated.

Thanks

Travis

[FishNette]

I get the feeling this may qualify as "rednecking". lol

[Curmudgeon]

Nice attic fan! I miss the one in my old house. It would move some air!

[Overkiller]

Good point on the gyro effect eating bearings, I had already planned on a support bearing but I guess rudders are in order too. I see what you mean about the volume vs. strength but I don't know enough about fans to look and tell the difference. The motor on the fan now is a 1hp electric, the pulleys are set up for a 3:1 reduction. I think the gas motor will have the nuts to spin the fan, my biggest concern was if the fan would handle the RPMs. It looks like a larger version of a engine driven fan on a car which I know handles high revs. If we get a slow day around the shop I might rig it up and see what it does.

[Robalo]

get an 18 HP Briggs, a real prop (and a cage), rudders and then all ya need in the aluminum tubing mount and the bote-and the stick rudder controls and an ignition and throttle.

That attic fan would shred into pieces IMO-be careful trying it.

My brother had the set-up I described above-had an airplane prop and would max out at about 15 mph on WOT (18' Jonboat-allweld). In a strong wind, you made very little headway-keep that in mind-that 1.5 hp aint gonna push it.

good luck and be careful. Oughta be fun.

[Shortystillsurfs]

We have an 11 hp honda with a 28" 2 blade prop, at full throttle ( with no head wind ) you are moving slower than a jog.

You are going to run into balance issues with that fan and you are guessing at how it will perform thru the entire throttle range of the 5 hp motor. Not to mention trying to pull start a motor while standing on the back of a floating boat that has that much surface area on the prop.

I wouldnt do it. Google Areoprop out of Oklahoma. You tell them the size of your boat , size of your motor and what your plans are. Then they spec out a balanced prop with a properly machined hub that corretly fits the horizontal motor shaft for very little money. In my opinion you will not be satisfied with gigger rigging your boat.......

There is alot more to consider..The motor and the prop are the only know factors. You need to design a light rail and wire it in to either 12 v or 110v you need reliable steering and thottle cables. Also mounting the briggs over the boat takes alot of work and quite a bit of consideration. I have built a flounder boat and bought a flounder boat. Buying one was the best option for me.

[mjh]

I have a friend of mine who builds these boats all the time. I can get you the hook up.

[Rollo]

Kresta's Marine in Edna,or also in Clute Tx. sells all things related to Flounder boats and put the safety hazord back in the attic, They can advise you what to do & how to keep all of it safe!

[FishNette]

Check out this link http://www.airboatfun.com/?page_id=180

[FishNette]

or this link http://www.youtube.com/watch?v=hS0nEX7DNvY

[TXSHOCKWAVE]

deff don't use the pos motor and fan. I have designed and built a few. There are several ways to do it just comes down to how much do you want to spend.

[Rollo]

Thats a nice clean setup mister! WTG!