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small air boat

c chardt

c chardt

Well-known member
I just got this mini air boat it looks to be 9 or 10 foot long and only about 5 or 6 ft wide It came with a 25 hp twin cyl motor I have to find a 1" prop flange and a prop for it and then re rig it for this engine any Ideas on what size prop to run
airboats_01-07_030.jpg
 
CC, I've got one that my 2 stroke Zenoah will turn with a redrive, and I'm gonna DD mine for my mini ....... I think yours would turn it. It's a Rotax 6-bolt pattern prop with LH rotation.

PM me and we'll talk about it.
 
Now that is cool, an airboat you can put in your truck. You could make the rigging mount with pins so it could be transported in a truck and set up on scene.

Draw me what you need to mount the prop and I will machine it for you. I have a bunch of aluminum plate I bought at a scrap yard 1/2" - 3" thick. I would feel safe casting parts for small engine applications also but not for high HP stuff. I will be firing up the foundry over the next two days to cast some trolling motor mounts like the one below.

Casting.jpg
 
alot of the guys here are running a 2 blade 48 to 50 inch IVO prop i on the 25 hp kohlers that are direct drive and seem to work well. If your running a belt drive you will need to run more prop 54 to 60 inches in two and 3bades depending on your reduction ratio.
 
Arrow prop and Universal hovercraft sell the prop adapters you seek. They utilize a prop mounting flange and a tapered split lock bushing. The ones from arrow are machined out of steel while the ones from Universal use a steel taper lock bushing and an aluminum prop flange. about 70 bucks or so either place. I I bought one from arrow prop and it is of the highest quality, it came with bolts and the round plate that goes on the back of the prop. good thing about these styles is that by simply changing the taper bushing you can change what size shaft you want it to go on ie: 1" or 1.25" etc...
 
fArrow prop I have seen many of thier propellers explode. and could tell you more but I don't want to discuss it on here.
 
Is there a link for those props that's all i will need to get it running and see what it will do
 
I believe arrowprops are made by ultra prop. I've run a 50" for a year now and have had no problems. We've tried the ivo with no luck. Most of the guys we run with are using either the arrowprop or powerfin. the powerfin is a nice prop, its designed similar to an airboat prop. Be sure and allot extra time for shipping because what ever they tell you it will always be longer!! on one boat we have we are running a 58" type b on a dd 35 hp briggs and it pushes awesome and will idle at 400 rpms.
 
Is there, or can anyone reccomend a hub size for a small engine?
RND Props will make the prop hub fit the hub, but I don't know what size to use.
I'm starting with a 1" shaft on the engine and planning on building a belt reduction for it, but need ideas for the hub.
With the reduction it's estimated to produce ~18hp @ 1800rpm.
 
FP1201":5c516zmv said:
Is there, or can anyone reccomend a hub size for a small engine?
RND Props will make the prop hub fit the hub, but I don't know what size to use.
I'm starting with a 1" shaft on the engine and planning on building a belt reduction for it, but need ideas for the hub.
With the reduction it's estimated to produce ~18hp @ 1800rpm.
Click to expand...

all you need is a hub from arrowprop with a taperlock bushing for what size crank you have and tell them what bolt pattern your prop is and they will fix you up. most of them are rotax pattern. not sure if that answered your question.
 
The local airboat/ jet boat builder has access to a guy who machines all his hubs for the small engines call Snyder airboats at 717 692-4294 I also know some guys who can machine a hub.
 
beebelawn":wr9wnr7u said:
FP1201":wr9wnr7u said:
Is there, or can anyone reccomend a hub size for a small engine?
RND Props will make the prop hub fit the hub, but I don't know what size to use.
I'm starting with a 1" shaft on the engine and planning on building a belt reduction for it, but need ideas for the hub.
With the reduction it's estimated to produce ~18hp @ 1800rpm.
Click to expand...

all you need is a hub from arrowprop with a taperlock bushing for what size crank you have and tell them what bolt pattern your prop is and they will fix you up. most of them are rotax pattern. not sure if that answered your question.
Click to expand...
Well sort of: See right now I have a 1" keyed shaft on the engine. Getting a pulley isn't any problem, and haveing a steel plate cut to whatever shape I want for the reduction to mount to is very do-able, I'm just trying to figure out the driven prop hub part. I ad though about using the fan hub off a large Diesel engine, but they are very heavy. I have seen a small trailer hub fixed to a plate with a pulley keyed to the axle stub deing run by a PTO. Somewhere I saw a hub that would slip over a 1" shaft w/ a 1/4" key, but there wasn't any indication of the bolt pattern. That proabably wouldn't make any diffrence as the prop could be made for the hub, however it would be prudent to start off with something that's already standard ie the "Rotax" pattern, so a diffrent prop from another manufacturer wouldn't be a major issue.
Thinking about it, using a trailer hub bolted to a plate might not be that bad an idea, certainly the bearings would handle all the speed and thrust that could possibly be generated out of such a small engine.
 
I have considered a finish mower spindle for the prop half of a reduction I want t build. It is similar to a trailer hub but already has a mounting flange with bolt holes, a shaft keyed for a pulley and a flange/mount to bolt on the prop's hub. They commonly handle 30-40 hp at the PTO on these mowers under very harsh conditions so they should take the load from a small motor.

Flat belts are way more efficient than V belts.
 
Thin water":197xm1pz said:
I have considered a finish mower spindle for the prop half of a reduction I want t build. It is similar to a trailer hub but already has a mounting flange with bolt holes, a shaft keyed for a pulley and a flange/mount to bolt on the prop's hub. They commonly handle 30-40 hp at the PTO on these mowers under very harsh conditions so they should take the load from a small motor.

Flat belts are way more efficient than V belts.
Click to expand...
No I hadn't, but that's an excellent suggestion! A serpentine belt would be a good choice, only down size is finding pulleys and the right sized belt and in some cases a tensioner....or maby I thinking too much into it.
 
well i measured it and it is 10 ft long and 5.5' wide with a 4.5' running bottom and is only 10" deep it has a deck and lid just like the big boats just a mini the nose is only 3 ft wide
 
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