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Now as title says, what adjustments do i need to make so airboat goes straight, thanks.

rcairboater

We need additional information such as the length, width and size of motor. All are factors here.
-Gary

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The airboat is 21" long and 14" wide with a 700-8.4 grauper with a single airrudder and will be powered by 2S lipo. The 700 is a guess but has plenty of get-up and go. The airboat is all wood. Thanks for replying.

Altered1

Setting the rudder correctly will do it.  You may need a little bit of left to counter rotation of the prop,  but this is minor.  Just make sure there is enough surface area and travel on the rudder.  the boat will turn easier into the rotation of the prop than against it, so allow a bit more travel against it.

If you're really worried, a heading hold gyro will work well too, but this is really not necessary. 

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Thanks alot!

asmithnc

Water Rudder.

1QwkSport2.5r

+10 on the wet rudder. You can ask Dadkins how well my boats turn with a wet rudder. We have ran together a few times.

You can get a good straight run with air rudders but you need to have *zero* slop in the linkages and dual rudders IMO.

1QwkSport2.5r

I went cheap in the rudder department and made my own. The wood was free and I spend about $6 on the brass parts and used regular electronics solder and flux to assemble the pivot and blade assembly. The rudder strut would be different for each boat depending on the transom shape/configuration.




A break-away is very important - unless you dont mind the transom getting ripped apart if you hit something. I have hit turtles twice, and other than a broken nylon screw the boat came away unscathed. I use captured ball/cup rod ends on the rudder so the linkage doesnt break if the break-away activates.


This is the ideal design IMO. A lathe and milling machine can make a much higher quality piece than what I made, but I dont have a lathe or milling machine.

Altered1

Great craftmanship there !   

1QwkSport2.5r

Thanks, Altered!
I have these and some pics of my other rudder I made over on the RCAW forum. Both kamikaze's have one of these rudders. If someone wanted to try one of these, I'd make one for the cost of shipping probably.

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Thanks for pitures. I'm getting ready for cancer operation on the 25 of July but your offering is alot to ask of anyone. I'll wait till i recover from it. Cancer is cured, thank god. I wasn't planning a fancy dan type of water rudder. Thanks for replying.If you make me one , only not a fancy dan, i'll gladly pay for your work and time..I'll make it 2 airudder system in the meantime. No bull on what i just typed, not my way of doing things. You WILL take the money too! Now 2 airudders is a snap in my boat but the flip up of prop has soaked in yet in construction.. I just took a walk and need a nap.

1QwkSport2.5r

I'll make you a rudder. Email me a picture if you can, and measurements of the transom. I'll glue up a block of wood when I get back into town. Laminating multiple pieces of wood like I did makes the wood more stable than a single large block. Less warpage that way.

Better yet, give me all of the dimensions of the boat so I can better tailor the strut length. I usually set my rudder so I have 3-3 1/2" in the water so the rudder still bites good in turns. The downside is weedy water is often problematic.

My email address is [email protected] . We can work out the details later. I could maybe have the assembly done before your surgery.

Good luck on your recovery.

Edit: If you have a decent pond or lake near you, I could bring your rudder to you personally instead of shipping it, and bring a boat or two with me. Just a thought. You're only 4 hours from me. Roughly.

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email add; [email protected] airboat is 24" x 12 "wide at top of transom and is tapered to 11" at bottom. Now it is 1 3/4" at transomdeep. Pond is moss but i bring a garden rake and pull moss in and away from area i boat. I get wife to send picture.Pictures are emailed , hope this helps, thanks.

1QwkSport2.5r

I got your email with the pictures. I will get something put together and I'll get back to you.

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Ok, got an idea, i have some brass that is a foot long and a1' wide and cut have lenghtwise and also i have a Original rudder. Now if i bend brass and screw into exterior of transom low. take the other bent piece and lay almost beside the the first. Lenght would be close to 5 1/2". Now the transom could be cut inside enough to out a 1 x 2 , 6" long for strenght and cover with 1 3;2" ply-top of transom.I can rivet the 2 long brass pieces for strenght. I have plastic break away bolts. Now for twin airrudders. i can drill down into 1 x 2 vertical about 4" apart. Slip brass shafts into holes and take some heavier rod and slide into brass for up right. The airrudders will be stationary and let the water rudder be the boss. Pretty hard to sync water rudder and airdder. I have a cross member for airrudder to maintain equal distance. What do you think?-Why need airrudder?s

1QwkSport2.5r

Basically, if you want your airboat to drive more like a car then you go wet rudder. If you want to be able to slide in corners and fishtail, then you want air rudders. You do not need to run both at the same time. In fact, it would be simpler to do one or the other. I have air rudders for my Big Kamikaze I can bolt on and I just set it up so the linkage for the wet rudder bolts right up to my air rudders so there is no need to change the whole linkage. (I like stuff to be as easy as possible) The best method I found that was light weight and strong was using some very small brass hinges.. Something you might see on a small jewelry box. These are the air rudder pivots. Then I just bent a piece of aluminum to screw the hinges to on top and used two small chunks of plywood that mount to the bottom of the engine stand. I will dig through my photobucket album and see if I have pictures of my setup and post them for you. All of my boats are Glow powered, so my engine mounts are larger and slightly more complex than yours... But the rudder mount doesnt need to be too complicated to be effective.

What material did you use for the transom of your boat?

1QwkSport2.5r

This is one of my build pics of the big kamikaze. Dual air rudders mounted to the back of the engine stand.


This is how I originally had the air rudder linkages set up. I have since changed the entire linkage around, but I dont have a current photo of it. The bellcrank on the transom originally doubled as the rudder bracket. I could unbolt the rudder blade to run air rudders only or leave the wet rudder on it with the air rudders. The linkage was poorly designed originally as it created some friction and made the servo have to work harder to center it..

All I did differently is instead of having a bellcrank on the hull to drive the air rudder I now just connect the control cable directly to one air rudder blade and this seems to work okay.

Edit: added pictures.

Horizontal mount, big Kamikaze

MiniKaze:

Altered1

Hey 1QwkSport2.5r,

I've been meaning to ask - the white holder for the golden rod on the rudder control line of the Minikaze - where did you get that ? Did you make that ?

1QwkSport2.5r

I made it myself from aluminum soffit material. It acts as a cable clamp and an anti-buckling device.

Altered1

It's a great idea, cheers

Altered1

1QwkSport2.5r

I use Sullivan semi-flex cables (.056" diameter) and I havent had one buckle yet, but I put the holder on there for insurance". Its what I like to call "Redneckin' it". lmao.

1QwkSport2.5r

Here's a few pics of the rudder strut I'm making..

Raw block, made from 1/8" +/- american cherry and red oak.

Carved it today. Each one I've done I carved differently.

1QwkSport2.5r

Evidently I had a duplicate post there for some weird reason.

edit: dupe post.

Altered1

I'm guessing here, but are you using a belt sander for the shaping?

1QwkSport2.5r

No. I made all of the cuts with my benchtop band saw and did my rough shaping with the band saw with final detail work done with a Dremel and 60 grit sanding drum. I followed with 80 grit sandpaper by hand to remove the scratches from the dremel and now I will drill the holes and get 2-3 coats of epoxy on it to seal it from all water intrusion. When the last coat of epoxy is cured, I'll topcoat the epoxy with polyurethane to drop the sheen from a "sticky" gloss to a slippery satin/matte finish. This makes a HUGE difference in how the water "sticks" to the surfaces.