Rudder blade bottom surface

[Tim_Duggan]

When trimming down rudder blades, what is the best shape for the bottom of the blade on mono's?

Straight cut, knife edged or rounded?

 

[Andy Greene]

When trimming down rudder blades, what is the best shape for the bottom of the blade on mono's?

Straight cut, knife edged or rounded?

I run the bottom edge flat and everything else as sharp as possible for an oval rudder. For sure take some length out , I also like to round the flat area just below the hinge pin- on the forward edge of the rudder-

on the Speedmaster rudders .

I would think a knife blade type taper would be well suited for SAWS

Dont know if those are really the right answers, but it seems to work for me.

Andy

 

[Joe Warren]

When trimming down rudder blades, what is the best shape for the bottom of the blade on mono's?

Straight cut, knife edged or rounded?

rounded....

 

[Andy Greene]

When trimming down rudder blades, what is the best shape for the bottom of the blade on mono's?

Straight cut, knife edged or rounded?

rounded....

Any particular reasoning on that theory Joe ? and would one hull brand favor flat or tapered ?

At one point or another it seems to me there was a thread about this a few years ago ???

For the life of me I cant find it.

Not stirring the pot- just interested in opinions B)

Andy

 

[Ed Knudsen]

Rounded or sharp "V" shaped - flat bottom tends to act like a sponson (ride surface)and can raise the rear of the hull - like a hydrofoil. Think of a flat bottomed strut on an outrigger.

 

[Tim_Duggan]

Thanks for the replies. B)

 

[Joe Warren]

When trimming down rudder blades, what is the best shape for the bottom of the blade on mono's?

Straight cut, knife edged or rounded?

rounded....

Any particular reasoning on that theory Joe ? and would one hull brand favor flat or tapered ?

At one point or another it seems to me there was a thread about this a few years ago ???

For the life of me I cant find it.

Not stirring the pot- just interested in opinions B)

Andy

keeps the blade from having a lifting surface. The tapered rudder blades want to craw out of the water looking for less drag resistance as it is. no need to give them lifting surface too.

 

[SeanKewley]

I was always told to add a radius to the bottom of the rudder to prevent it from becoming a planing surface.

 

[dwilfong]

I run mine flat bottom different than most and a strait blade. I think a little lift on the rudder compensates for the right hand roll from the prop.

Just what seams to work on my setup.

David

 

[nitrotwin]

There's nothing as pretty as a nice round bottom

 

[Andy Greene]

I run mine flat bottom different than most and a strait blade. I think a little lift on the rudder compensates for the right hand roll from the prop.

Just what seams to work on my setup.

David

David, that thing runs ragged edge all the time- but it sure huals azz in the straights- :huh:

You ought to be just fine in the am btw

Just keep it off the pins- okay- lol ......

Kidding

Watched ya run for a bit today- didnt get a chance to catch up to you and say hello- had to leave early.

See ya in the am ...

Andy

 

[dwilfong]

Andy Took off the X455 and put the AB 5077 on and it settled down. Got dick to pinch the sleeve and ran 4 tanks thew it runs much better now. B)

Hope I don't crash

Just hard to start should be good by the 3rd heat.

See you in the AM.

David

PS I put the X457/3 on you should have seen that action. B)

 

[Mike Hughes]

Here another little trick for those days that are really rough and you do not want to have to change you setup. Take a piece of radio box tape and fold it in half over the leading edge of the blade, so it tapes back onto itself. Now you have a little flag hanging off the back of the blade this will cause drag and settle the boat down. The longger the tape, the more drag. Easy to do and change.

Mike

 

[SeanKewley]

Nice Tip. Thanks!

 

[Tim_Duggan]

I tried my SD3 33" yesterday after changing the shape of the bottom of the blade from flat. Made a noticable difference to the feel of the boat, for the better.

Thanks for the info guys!