31cc gas airboat
04-05-2008 | 03:34 PM
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From: collegeville,
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31cc gas airboat
hello everyone. im in the middle of making a 4'X2' foam glass airboat and was wondering how should i make the rudders? the project is moving along very well and i had to stop today cause i ran out of welding wire. the engine is a 31cc ryobi that is swinging a 26X10 3 blade prop and an 11mm carb on instead of the really really small one that was there. im making the prop cage out of brake line and its going to be 4" deep. i want to attach the rudders to the top of the cage and to the back of the boat. i was wondering if there are any ideas best to do that. im gonna get some wire than put a could pictures up of what i have so far. thanks everyone
04-05-2008 | 04:39 PM
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From: onalaska,
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RE: 31cc gas airboat
26 x 10 prop !?!? way too big for that engine. I hope that's a typo. even so, a 16 x 10 would be too large of a pitch, you would need a 6 or 8 pitch. Are you going to have a puller or a pusher (like a real airboat)? A weedeater engine in a pusher configuration will require you to have a pusher prop.
2 feet wide is also a smidge wide IMO. it would certainly slide well in the corners.
really a rule of thumb is to have the bottom of the boat about 1-4 inches wider than the diameter of the prop.
Here are some ideas for mounting your rudders.
2 feet wide is also a smidge wide IMO. it would certainly slide well in the corners.
really a rule of thumb is to have the bottom of the boat about 1-4 inches wider than the diameter of the prop.Here are some ideas for mounting your rudders.
04-05-2008 | 08:22 PM
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From: Lexington,
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RE: 31cc gas airboat
ORIGINAL: crispyspa
26 x 10 prop !?!? way too big for that engine. I hope that's a typo. even so, a 16 x 10 would be too large of a pitch, you would need a 6 or 8 pitch. Are you going to have a puller or a pusher (like a real airboat)? A weedeater engine in a pusher configuration will require you to have a pusher prop.
2 feet wide is also a smidge wide IMO. it would certainly slide well in the corners. really a rule of thumb is to have the bottom of the boat about 1-4 inches wider than the diameter of the prop.
Here are some ideas for mounting your rudders.
26 x 10 prop !?!? way too big for that engine. I hope that's a typo. even so, a 16 x 10 would be too large of a pitch, you would need a 6 or 8 pitch. Are you going to have a puller or a pusher (like a real airboat)? A weedeater engine in a pusher configuration will require you to have a pusher prop.
2 feet wide is also a smidge wide IMO. it would certainly slide well in the corners.
really a rule of thumb is to have the bottom of the boat about 1-4 inches wider than the diameter of the prop.Here are some ideas for mounting your rudders.
He is a great Gasser boat builder. Listen to his advice and use it.
04-05-2008 | 10:53 PM
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From: collegeville,
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RE: 31cc gas airboat
ya my bad. its a 16X10 pusher. just like the real thing. here are a couple of what i have right now. i have the boat that is not complete. pink foam. that ryobi with the carb that i put on reves relly well and you can tell that it is where it should be. im a mechanic and have worked on weed wackers for a while. so i do believe that that part of this project is right at least that part. and i like to do alot of research befor i buy anything or do anything. thats just how i am. so i did find out by a couple different spots about the car and propeller. so we will see. and i really do like how you made your cage. very clean and i see that you can take it apart if you want to, nice option. i know that i want my rudders to be removeable. but the cage is going to be made from brake line and a thin wire mesh to go around. i have seen props break and not a fan (lol no pun there) of a blade in my eye. but so far this is what i have and any more ideas to make this better woule be awesome!
04-06-2008 | 11:55 AM
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From: onalaska,
WI
RE: 31cc gas airboat
Can't really tell from the pics, but the diameter of the bow rake looks like it could be larger.
I like to make my rudders roughly 2/3 the size of the prop for height and 1/4 the size for width. Example: 16" prop = 10 x 4.5 rudder. Then center the rudders with the crankshaft.
The rudders in the pics above are 10" tall and 5" wide at the top and 4" wide at the bottom.
1/4 " Plexiglas?? Hmmm, never thought about it. You could use it, then, sand and shape the plexi to a wing shape, bull nose towards the prop and taper out to the back, then wet sand and buff to clear...that would be cool!
I like to make my rudders roughly 2/3 the size of the prop for height and 1/4 the size for width. Example: 16" prop = 10 x 4.5 rudder. Then center the rudders with the crankshaft.
The rudders in the pics above are 10" tall and 5" wide at the top and 4" wide at the bottom.
1/4 " Plexiglas?? Hmmm, never thought about it. You could use it, then, sand and shape the plexi to a wing shape, bull nose towards the prop and taper out to the back, then wet sand and buff to clear...that would be cool!
04-06-2008 | 01:45 PM
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From: collegeville,
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RE: 31cc gas airboat
http://www.rcuniverse.com/forum/m_72...tm.htm#7285615 . i have the 3 pictures about 3/4 the way down the page. it shows the rake there. the rake goes back 1/3 from the front and the ballance point is 1/3 from the back. thats my goal. and thanks for the input for the sizes. and for the position of each rudder you said center them. well if its a 16" prop. half is 8" so i should moint each rudder 4" from center. does that sound about right? i am so glad that i have found this forum. this is my first airboat and first big project from scratch and there are alot of people that are happy to lend their knowledge of what they have. the r/c crowd is a special crowd. THANKS EVERYONE
04-06-2008 | 03:24 PM
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From: Katy, TX
RE: 31cc gas airboat
ORIGINAL: luckytempo93
ya my bad. its a 16X10 pusher. just like the real thing. here are a couple of what i have right now. i have the boat that is not complete. pink foam. that ryobi with the carb that i put on reves relly well and you can tell that it is where it should be. im a mechanic and have worked on weed wackers for a while. so i do believe that that part of this project is right at least that part. and i like to do alot of research befor i buy anything or do anything. thats just how i am. so i did find out by a couple different spots about the car and propeller. so we will see. and i really do like how you made your cage. very clean and i see that you can take it apart if you want to, nice option. i know that i want my rudders to be removeable. but the cage is going to be made from brake line and a thin wire mesh to go around. i have seen props break and not a fan (lol no pun there) of a blade in my eye. but so far this is what i have and any more ideas to make this better woule be awesome!
ya my bad. its a 16X10 pusher. just like the real thing. here are a couple of what i have right now. i have the boat that is not complete. pink foam. that ryobi with the carb that i put on reves relly well and you can tell that it is where it should be. im a mechanic and have worked on weed wackers for a while. so i do believe that that part of this project is right at least that part. and i like to do alot of research befor i buy anything or do anything. thats just how i am. so i did find out by a couple different spots about the car and propeller. so we will see. and i really do like how you made your cage. very clean and i see that you can take it apart if you want to, nice option. i know that i want my rudders to be removeable. but the cage is going to be made from brake line and a thin wire mesh to go around. i have seen props break and not a fan (lol no pun there) of a blade in my eye. but so far this is what i have and any more ideas to make this better woule be awesome!
04-06-2008 | 07:23 PM
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From: Lexington,
NC
RE: 31cc gas airboat
I buy the foam at Home Depot or lowes. It come in a 4 x 8 sheet. I like the 2" over the 1" and 3". The glue you speek of.... It's epoxy resin. I like Bob Smith Industries it's little $ and does a great job. If someone recommends West systems, well.... it's ultra expensive. 5-30 min for bonding and 20 finishing resin is for water proofing exposed wood and fiber glassing. Need more help just ask and good luck.
04-06-2008 | 09:14 PM
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From: collegeville,
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RE: 31cc gas airboat
i purchased the foam at home depot. in the far right corner about 3 isles in. all home depots are the same. lol. well i used the 2" 4X8 sheet and used a band saw to cut it square cause there a tongue and grove to put pices next to each other. MAKE SURE YOU HAVE A SHOP VAC TO CLEAN THE MESS UP. the foam gets everywhere. and i used a belt sander and a palm sander to do all of the shaping. the belt took off the material fast and the palm for smoothing and rounding. and for epoxy, i just bought the GREEN KIT from http://jgreer.com/ . i have been told i should only need a quart and a half to do the entire project. and im using 4oz cloth. i will let everyone know how well the epoxy goes and keep you updated on this project
04-06-2008 | 11:38 PM
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From: onalaska,
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RE: 31cc gas airboat
lucky wrote:
^ I think you are referring to rudder spacing.^
I should have elaborated.
Looking at the boat from the side, I center the rudders top to bottom with the crankshaft.
spacing is done by figuring out how much prop the rudders will "cover" whilst fully turned....In my case I "cover" approximately 3/4 of the prop. which is a 6" spacing of the rudders. seems to work real well.
Yes there are. A couple of years ago I joined and without the help of Self Inflicted, Mr Cajun Gator, asmith, and a host of others, I wouldn't have the knowledge that I have today.
for the position of each rudder you said center them. well if its a 16" prop. half is 8" so i should moint each rudder 4" from center.
I should have elaborated.
Looking at the boat from the side, I center the rudders top to bottom with the crankshaft.
spacing is done by figuring out how much prop the rudders will "cover" whilst fully turned....In my case I "cover" approximately 3/4 of the prop. which is a 6" spacing of the rudders. seems to work real well.
there are alot of people that are happy to lend their knowledge of what they have. the r/c crowd is a special crowd.
04-07-2008 | 02:04 PM
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From: sanford, FL
RE: 31cc gas airboat
[/quote]Yes there are. A couple of years ago I joined and without the help of Self Inflicted, Mr Cajun Gator, asmith, and a host of others, I wouldn't have the knowledge that I have today.
[/quote]
same here crispy
04-08-2008 | 09:37 PM
#13
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RE: 31cc gas airboat
Looking at the rake it looks to be ok. the main thing I would give a closer look to is the sides, there may not be enough surface there to prevent bitting in the turns at slower speeds. High speed turns you should be ok.
I really do hope that I have given everyone good advice in the past, thanks.
I really do hope that I have given everyone good advice in the past, thanks.
04-08-2008 | 10:15 PM
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From: collegeville,
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RE: 31cc gas airboat
thank you Mr Cajun Gator. how should the sides be? i am also wanting to run this off of water too so i dont want the sides too sharp to where they will crack aor bite too hard. and also i do have to fiberglass this. i just got the epoxy and fiberglass today. and im trying to figure out how the servos and linkages are going to be made up.
04-14-2008 | 09:47 PM
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From: collegeville,
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RE: 31cc gas airboat
its been a while since i have done some work. here are some pictures of my cage. im thinking it looks good for my first one. i have also been working on my radio area. its difficult to get a straight shot from the hole in the foam to flush with the top of the engine area ehere the rudder and throtle cables will be coming out.i was able to get a drill bit and kinda saw away the foam and get the cables through. its looking good.
04-15-2008 | 08:57 AM
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From: Lexington,
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RE: 31cc gas airboat
ORIGINAL: crispyspa
That is a darn nice first cage. Let us know how that engine runs out.....I have one just like it sitting, waiting for a hull.
That is a darn nice first cage. Let us know how that engine runs out.....I have one just like it sitting, waiting for a hull.
04-15-2008 | 11:56 AM
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From: collegeville,
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RE: 31cc gas airboat
thanks guys. i have to finish welding the joints in spot and add another support to the engine cause it vibrates really bad. and than i have a fine wire sheet that i am going to put over top of the cage cause i get wacky when i see a prop spinning w/o protecton. and than to the rudder assembly.
04-15-2008 | 10:51 PM
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From: collegeville,
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RE: 31cc gas airboat
DONS BOAT WORKS... thats a really nice cage you have there. what size prop were you using and did you follow the advice from above on what size to make the rudders? i have a 16X10 3blade and its 1.5" off the bottom of the boat. so the tip of the prop is 17.5" tall. i was thinking that i would make mm rudders 14" tall and 6" wide. what do you all think.or will that be too big and would not handle propertly
04-15-2008 | 11:20 PM
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From: Sanger,
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RE: 31cc gas airboat
ORIGINAL: luckytempo93
DONS BOAT WORKS... thats a really nice cage you have there. what size prop were you using and did you follow the advice from above on what size to make the rudders? i have a 16X10 3blade and its 1.5" off the bottom of the boat. so the tip of the prop is 17.5" tall. i was thinking that i would make mm rudders 14" tall and 6" wide. what do you all think.or will that be too big and would not handle propertly
DONS BOAT WORKS... thats a really nice cage you have there. what size prop were you using and did you follow the advice from above on what size to make the rudders? i have a 16X10 3blade and its 1.5" off the bottom of the boat. so the tip of the prop is 17.5" tall. i was thinking that i would make mm rudders 14" tall and 6" wide. what do you all think.or will that be too big and would not handle propertly
Thank You
Don M.
PS
Just call me Don.
04-21-2008 | 08:08 PM
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From: collegeville,
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RE: 31cc gas airboat
no i have not forgotten about it. i have been doing small stuff in my spare time. we got 23 ton of stone 2 fridays ago that needed to be spred over my driveway. soo... but i am in the process of making the holes in the foam for the linkages and just standing there looking at my masterpiece figuring out in my head all the little things that need to be done. thanks for being so interrested in my project so much. i have the engine cage and braced strong enough. that prop pushes hard. so my next step is to cover the foam with spackle than fiberglass, its still a little cool to let the epoxy set. but i want to wait a couple more days till that cause i ALWAYS forget something and i dont want it to be too late. I WILL KEEP YOU ALL INFORMED ABOUT MY PROGRESS.
04-21-2008 | 08:20 PM
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From: Okeechobee,
FL
RE: 31cc gas airboat
Luckytempo,
Nice work! I like your cage work. One of the best cages I have seen! It looks like full size airboat cages with the motor mount being incorporated in the cage. Once again, nice work!!
Looking forward to seeing this creation come to life.
Nice work! I like your cage work. One of the best cages I have seen! It looks like full size airboat cages with the motor mount being incorporated in the cage. Once again, nice work!!
Looking forward to seeing this creation come to life.
