Mini air boat

[Basstronics]

Another project! Yippee!!!

Looking to build a mini air boat. I want to use my Mystery D2632 3000kv outrunner & 30A esc.

Im looking at 16" long 8" wide.

Trying to get an ideal prop size worked out so I know how to build it.

Going to work on the CAD model tonight some.

[damfurst]

I'll be interested to see how this goes. I think that you might only be able to run a 6 inch prop on your mystery motor. I have an Exceed 1800kv motor that anything over a 7" will heat the motor. I think I'm going to try and put it on the back of a extra Mini-C hull I have. Hope you post pics.

[sailr]

If it is a 26mm x 32mm outside dimensions, 3000KV, it should swing a 8 x 4.7 apc electric prop. My Storm outrunners that size but 1250KV will swing a 10 x 4.7 all day long on 3S lipo.

[Diegoboy]

For reference (http://forums.offshoreelectrics.com/showthread.php?t=4635)...

[bwells]

What about using an EDF (electric duct fan)? They are cheap and a lot safer. There was a build on here using one of these a while back.

[Chop]

For reference (http://forums.offshoreelectrics.com/showthread.php?t=4635)...
Hey! I have that boat now!!!


What about using an EDF (electric duct fan)? They are cheap and a lot safer. There was a build on here using one of these a while back.
Hey! I built that boat…
http://forums.offshoreelectrics.com/showthread.php?t=11893

[Basstronics]

I think I will stick to a prop.

10-4 on that 8" prop size. I want to order parts this weekend.

Its going to be a balsa-lite ply construction. I will end up putting a thin layer of fiberglass on the under side once I prove it in the pond.

CAD model coming soon.

[Basstronics]

I got the basic hull design done for now.

Going to order the prop adapter and a few props this weekend.

Attached is a PDF of the CAD file. Its still rough as far as the CAD goes. I have all the pieces figured out.

The boat will have a 2 degree included V- 178 degrees. There is also a 1 degree on the rear. So if you build the motor flat to the top and use the design as is, the motor will be 1 degree angle towards the sky.

Thoughts on these angles? I dont want to much lift but I would like to reduce drag- hopefully 1 degree is good enough.

[Chop]

In your section views you show the sides to be almost 90 degrees from the deck.
If you put the sides at about a 55 degree angle to the top deck the boat will slide around the corners rather that having to sharp edge to bite into it (making it more likely to tip).

[Basstronics]

Ah OK. I built this kind of like my lil swamp buggy...

I will put some angles to it tonight.

[Chop]

Ah OK.
Sorry, I'm no expert; build it the way you see fit.

I do see an obvious difference in the way the two boats (pictured in post #6) turn. The small one has straight sides and tips badly in turns; the large boat has angled sides and slides through them (the ducted fans lower C.O.G. helps with this too).

[sundog]

Yes, tipping. It would seem that 2 ducted fan units would do the same, only with a lower center of gravity. But I don't like the slow 'get up and go' in airboats. Was thinking of incorporating 2 ducted fan units on a jetboat (or a jet drive in a ducted fan boat) for quicker response. :w00t:

[Basstronics]

Ok I got it done today and I got the parts printed out. Im going to start cutting wood now.

Attached is the overall then 3 sheets of 8.5" x 11" paper printouts. So if anyone else wants to build this they can.

I upgraded the wood to 3/32" Balsa. I added some 3/32" x 1/4" Balsa runners to help stiffen things up.

Will post pics later.

[Basstronics]

I just discovered the hard way that I bought 1/8" and 3/32" thick Balsa...

Dangit!

[Basstronics]

Update.

I need to build the motor structure now. Also have to figure out how I am going to do the rudder.

This is going to be a puller. Should I go with one rudder or two?

http://i38.photobucket.com/albums/e136/basstronics/RC%20Boats/100_7307.jpg
http://i38.photobucket.com/albums/e136/basstronics/RC%20Boats/100_7304.jpg
http://i38.photobucket.com/albums/e136/basstronics/RC%20Boats/100_7302.jpg
http://i38.photobucket.com/albums/e136/basstronics/RC%20Boats/100_7301.jpg

[Basstronics]

Is there any balance rule I need to be mindful of? Every airboat Ive seen is the engine way in the back...

Does the design of the uprights that hold the motor up make any difference? I can make them about 2" apart and straight up off the hull- or I could angle them so they are about 2" at the top and 4" at the bottom. Or will this factor in with 1 rudder vs 2 and the placement of those rudders?

[monojeff]

Not sure if you have ever seen this forum before but a lot of great info on here you can look through http://www.rcairboats.net/phpBB/index.php

Boat is looking :thumbup:

[Chop]

You've got a real nice start there!:rockon2:

I have 2 airboats, one with 1 rudder, and the other with 2. The profile of the single rudder is much bigger than the profile of the dual rudder boat.

I believe that the single (larger) rudder is less stable and more prone to influence from cross winds (tipping, blowing off course, plus a higher center of gravity). My personal opinion is to go with 2 smaller rudders.

Keep up the good work.

[Basstronics]

Ok Im gonna go with two rudders then. Gonna work on it tonight some more.

[Basstronics]

What a wicked fail today.

I decided to just see what this thing could do. So I mount the motor, put the spinner and the prop on. Go at it with 2S (this is a 3000kv motor).

And I fire it up. Got it going right. Get on it a little, man that thing was pulling some air... Then...

http://i38.photobucket.com/albums/e136/basstronics/RC%20Boats/100_7387.jpg

http://i38.photobucket.com/albums/e136/basstronics/RC%20Boats/100_7386.jpg

The mount was epoxied onto the uprights only. I have two layers of real light fiberglass down to the hull. One layer of glass over the hull deck/front lip. The uprights are 1/16" birch ply. Should I remove the mounts and do something different??? Or just reattach and add more wood behind it?


The motor is a total loss- good thing I have another.

[bwells]

The uprights are 1/16th or 1/8th? It looks to be 3 ply. Get an EDF and ditch that flyboy crap!

[Basstronics]

The uprights are 1/16" with two layers of super light glass cloth.

[bwells]

Can you still clean up the uprights and do the same thing and add 2 pieces of ply to the uprights, above and below the motor fastened front to back? That should hold it. Just a thought.

[Basstronics]

Well I need to go back to the drawing board on this.

Here is a list of props I bought- would like to use the larger props:
7x4.5E
6x5E
6x4E
8x5E
8x4E

I need to figure what the optimum RPM for these props are and get a motor/spinner setup to accommodate that. Im sure my boat size plays into all of this but getting info on something like this is much like pulling hens teeth.

Im probably going to have to cut my uprights off and start over on those. Thats OK to me. After seeing the output on this setup and I was quite shocked. After seeing the power after it ripped itself apart Im now scared.

I dont really want to do an EDF. I kinda wanted the prop look.

[bwells]

Can you chop off the uprights below the original mount and add to them and beef up the mount area? It looks as though the hull to upright connection was good and took the pressure.

[Chop]

Any progress on this lately??

It's been a fun build to watch.
:beerchug:

[Basstronics]

Well I bought a new motor and some wood.

Just havent had the time or felt up to messing with it lately.

Heres the motor:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=120449687355

Upringhys are going to made from 1/8" ply, with the motor mount forward keyed into the other wood so it cants just fly apart. Going to give it two layers of super light glass on both sides of both uprights. Somewhat considering a single upright also...

Gotta figure out a rudder scheme.

Lots of thinking to do.

[Basstronics]

Success finally!

My new motor mount structure has held up to a 6" and now a 7" prop. Not trying an 8" until on the water.

I bought the flex cable styled push rod. I have 1/2A mini horns. I had to special over some .032" micro clevis and ball links. not sure which I will end up using.

Today I fired it up. The 6" prop wouldnt pull it. The 7" would move it along the floor but not much. The battery isnt fully charged either...

Heres some pics. Not how I did the rudders. The piano wire on the actual rudder is like .015" undersized so it floats real good ;)

http://i38.photobucket.com/albums/e136/basstronics/RC%20Boats/100_7417.jpg
http://i38.photobucket.com/albums/e136/basstronics/RC%20Boats/100_7418.jpg
http://i38.photobucket.com/albums/e136/basstronics/RC%20Boats/100_7419.jpg
http://i38.photobucket.com/albums/e136/basstronics/RC%20Boats/100_7420.jpg

[bwells]

Your vane hinges are top of the line, good job!

[SweetAccord]

HK has one now:

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=17899

[Basstronics]

On back order... And it probably costs $40 to ship it here...

Looks interesting. Its what AQ should do instead of all that brushed stuff...

[sailr]

...and you still have to buy an esc for it. There's another $40 or more. I'd steer clear of that thing. JMHO. I bought one of their outboards and it was the biggest piece of crap I've ever seen not to mention they advertised it as a 540 motor (typically 36mm diameter motor) and it in fact had a 380 size, 28mm in it. To top it off, the esc blew in the first one minute of use. I lost my butt selling and shipping it in the swap shop.

Lessons learned.

[Basstronics]

I think I would go for it if I was in the market for one.

You gotta be careful what you buy. I only buy whats tried and tested.

[Basstronics]

Update.

Now that the power system has been sorted out it was onto control.

I noticed some pictures of people using the flex pushrods w/braided line. So I went that route. Works well. My boat is so short that I truly need a smaller cable... But I got it to work!

I ended up ordering the Dubro Micro Ball link (.032") for the top. After assembling it all I noticed the bottom was a little loose. So I got another set. Got it all in tonight and works wonders. Note that you must accurately locate the second set of ball links. I used a scale and my eyes and I must be damned close as it moves with no hang up... My point is if you are building similar its probably best to plan this part before mounting your rudders... Otherwise it makes it much more difficult.

My next step is to but a layer or two of glass over my piano wire hinge pins which are just epoxied onto the wood. One broke loose as i heated it up to much cutting the steel rod w/ dremel tool.

Pictures:

http://i38.photobucket.com/albums/e136/basstronics/RC%20Boats/100_7467.jpg
http://i38.photobucket.com/albums/e136/basstronics/RC%20Boats/100_7466.jpg
http://i38.photobucket.com/albums/e136/basstronics/RC%20Boats/100_7465.jpg
http://i38.photobucket.com/albums/e136/basstronics/RC%20Boats/100_7463.jpg
http://i38.photobucket.com/albums/e136/basstronics/RC%20Boats/100_7462.jpg

[Basstronics]

Got the paint done as far as its going to go. So I put it together. Then I got to run it.

http://i38.photobucket.com/albums/e136/basstronics/RC%20Boats/100_7480.jpg
http://i38.photobucket.com/albums/e136/basstronics/RC%20Boats/100_7481.jpg
http://i38.photobucket.com/albums/e136/basstronics/RC%20Boats/100_7482.jpg
http://i38.photobucket.com/albums/e136/basstronics/RC%20Boats/100_7484.jpg
http://i38.photobucket.com/albums/e136/basstronics/RC%20Boats/100_7485.jpg

[Basstronics]

http://www.youtube.com/watch?v=JciTLAUyCcc
6x5e prop. Using some older AM XPS remotes. I didnt have the throttle setting on "hi" cranked all the way up so I was not getting full power until my last video.

More video's to come!

[SweetZ28]

Hi looks good.
I bought a aquacraft mini alligator tours and converted it to brushless.
Here it is on 2S lipo.

http://www.youtube.com/watch?v=_M9PLGLvo-g

[Basstronics]

http://www.youtube.com/watch?v=TzHtfReMBXQ

7x4.5e

Same throttle issue...


http://www.youtube.com/watch?v=GndXJbMk26Y

8x5e


http://www.youtube.com/watch?v=WYWRVlMvSG8

8x5e throttle corrected- full tilt crash! ouch!

[SweetZ28]

Hi years back i used to build airboats lots of guy's recomend tilting the prop on a slight angle...think it was slight like 5 to 7 degrees... try putting a couple thin washers under the bottom motor screws so it tilts the prop up tawards the sky just a hair so the wind gets thrown at a slight angle towards the water behind your boat ..play around will more and less washers to find the sweet spot you may be able to get some faster speeds and better thrust to push the boat farward .... you can even try the smaller prop that did not push it to well.

[Basstronics]

Hmmm. I was thinking the exact opposite. The boat tried to take flight a few times. Especially when a gust of wind caught the sides went under the boat. When I got on it with the throttle fixed up only a bit of the boat was in the water.

Im quite pleased so far. Just need to get it out and try again.

More videos to come tomorrow, weather permitting.

[SweetZ28]

I think it's just the oposit... search RC airboats on the web and look at the photos of boats sidways you will notice most have the prop angled up a little.

[LarrysDrifter]

Thats sweet! I think I just found my next build. Good job, looks like fun.

[Basstronics]

Im going to update my CAD drawing with my lessons learned and build another one.

The motor I used is still available by the e bay link. It took a good month to get it!

[SweetZ28]

There are 2 companies that sell lazer cut airboat kits you put together they are not to expensive why not buy a pre cut kit that was tested and perfected already?

[Basstronics]

Oh?

Never knew about them. Got links?

Ive built a small swamp buggy 15 years ago.

[SweetZ28]

Anarchy
http://www.claserdesigns.com/anarchy.html

and steves aero models
http://www.claserdesigns.com/anarchy.html


don't know what one is better the anarchy one looks better to me... do a video search i know theres videos of both .

[Basstronics]

The anarchy one looks cool but I dont like the single rudder.

Well Im now an unemployed designer- mechanical engineer. So I like to design things ;)

I think I may just rework my current design with lessons learned and have a few kits burned out. My boat has a bigger motor and larger prop than theirs. So its more performance oriented I hope.

Time will tell.

No runs today- going to Cedar Point instead!

[SweetZ28]

I think your boat is set up way wrong did you see videos of there boats they fly!
they are much faster than yours and they drive way better.
search for videos see for yourself...they may show videos on there site also if not you tube them.


The anarchy one looks cool but I dont like the single rudder.

Well Im now an unemployed designer- mechanical engineer. So I like to design things ;)

I think I may just rework my current design with lessons learned and have a few kits burned out. My boat has a bigger motor and larger prop than theirs. So its more performance oriented I hope.

Time will tell.

No runs today- going to Cedar Point instead!

[LarrysDrifter]

This build has me ready to start building. Does anyone know what size edf unit I would need for a ul1 motor on 4s using a 25"-28" long wood hull? Where can I buy an edf in the states? Sorry to booger you thread, I can/will start my own.

[Basstronics]

I think your boat is set up way wrong did you see videos of there boats they fly!
they are much faster than yours and they drive way better.
search for videos see for yourself...they may show videos on there site also if not you tube them.

I have watched the video on the first link you provided. Sorry to disagree with you again, but I dont think their boat is faster.

My boat already wants to take off into the air. So the logic of pointing the prop more into the air seems a bit off to me. I dont want to pull my boat more out of the water into the air- thats the problem. I want to plant it some more in the water. So I fail to see how its so "setup way wrong".

I think my air rudders could be a touch bigger. I think I need to add some radius on the bottom and remove the strake on the bottom. These are those "lessons learned" I mentioned earlier about incorporating into version #2. As you read my last point Im currently unemployed- so I have a bit of time to try new things...

[SweetZ28]

Search youtube they may not be faster but you can tell there set up is working...
also adjusting the prop a little up or down will tune the way your boat rides.... Most airboats have the nose of the spinner tilted down a few degreese... I said the oposit in my post above I made a mistake BUT some times your boat may run better with a few degrees up on the prop it's all trial and error.

I built way faster airboats than what you have and trust me playing with the prop angle adjusting it a few times you can make your boat run much better.



I have watched the video on the first link you provided. Sorry to disagree with you again, but I dont think their boat is faster.

My boat already wants to take off into the air. So the logic of pointing the prop more into the air seems a bit off to me. I dont want to pull my boat more out of the water into the air- thats the problem. I want to plant it some more in the water. So I fail to see how its so "setup way wrong".

I think my air rudders could be a touch bigger. I think I need to add some radius on the bottom and remove the strake on the bottom. These are those "lessons learned" I mentioned earlier about incorporating into version #2. As you read my last point Im currently unemployed- so I have a bit of time to try new things...

[Basstronics]

Oh OK I didnt think that seemed right.

My boat is setup with the hull having a slight angle and my motor mount was built flat, the resultant is a very slight angle upward.

Im going to try and get more video tonight or tomorrow.

[Basstronics]

21.4mph
23 something amps

I went back the review the eagle tree data and upon doing so it didnt register any speed. The 21.4 might be from a previous run as I cant get any speed number off the log file I saved.

Odd!

[SweetZ28]

54844Hi Basstronics see attached photo notice the prop angle to the vertical bar on the roll cage.... If i can recall from my airboat building days guy's used to run 5 to 7 degrees angled down.