Horizontal Stabilizer

[hugh hargett]

Im working on one of my scales and am curious as to what angle folks are running on the horizontal stabilizer in relation to the water line?I see people have them set in place with no adjustability? Why?

It was my thinking that when it up on plane id want the wing parallel with the water line. How skewed am I in my thinking scale guys?

 

[Hydro Junkie]

It depends, are you talking the rear wing or the canard? Both have different uses in setting up the hull

 

[hugh hargett]

Horizontal stabilizer is all I know I dont know anyting about rear canards on a 89/90 u-31 lets not over complicate things please HJ. This is a real simple question im just looking for real simple answers. There is no mention of rear canards here so all we need to talk about is the horizontal stabilizer aka the rear wing!

 

[TimothyJones]

I have seen a lot of people using adjustable rear wings. There even has been a discussion on applying a servo to it.

Is this the right page or am I complicating things!!

 

[BobGutsell]

Rightly or wrongly I set mine about parallel with the rear deck. Bearing in mind the rear deck is sloping downward toward the transom. I also build my wings as close as possible to a lifting wing profile, flat underside, with an aerofoil shaped upper.

Like to think that I'm build some lift into the rea wing. But I'll accept it's debatable about how effective the lift is. The one thing I think you aboslutely don't want is downforce at the back end.

BTW Hugh, HJ looks like he was asking you whether the horizontal stabiliser you were asking about was the Canard at the front or the rear wing. You've since clarified it's the rear wing you want to know about.

 

[hugh hargett]

I too thought of a wing shape but because of the absense of a wind tunnel I have no idea how much lift that one off wing will generate I dont want to be pulling the prop out of the water.

Tim I like the idea of active surfaces but its my belief that they need to be autonomous to really make an impact. The idea is not too complicated but the execution requires alot of time testing and a proper algorithm.These type ideas get shot down consitently so until someone actually puts it into work and makes it work we wont waste our time with it here. Im talking static adjustments.Im thinking its more dependent on the boat how it needs to be. Bob g what scale you running your deck parallel setup on?it is a transom heavy boat or is it reasonable? Im thinking more negative angle than whats needed will only create drag.

 

[BobGutsell]

I run the 1987 Cellular One in my avatar, and yes it's quite a tail heavy boat. Can't really get the lift I need from it without running a ride pad on the stuffing tube and a pitched up 1455. I haven't tried running the boat without a ride plate since trying the 1455, it might sound like a small prop but I don't run any nitro at all.

If I run 455 2 blade or 3 blade, or a 245 prather without the ride plate I don't get enough lift irrespective of what angle or profile the horizontal of the tail is. I wouldn't be too concerned about lifting the tail of your boat out of the water, I don't think a wing profile can generate that much lift. It certainly doesn't on mine.

I've set my Oberto up the same way, but it's about 2-3 weeks away from paint so will be a while before I know how it runs.

 

[hugh hargett]

My Circus is 14 pounds loaded with all the gear in front of the motor the cg sits about 1.5 to 2 inches behind the tsponsons trailing edge. I really dont think its that tail heavy note the circus also sports rear skis.So its hard to judge it.I was planning on a newr boat but for now im going to play with this dumas. hopefully I can get her on the water next week. She sports a 1527 1y I plan to run it on 8slipo with a texascut Beardslee 457/3,455, or an Andy Brown full bladed x457. I hope it does well.

Tim jones pm me and we can talk more about autonomous surfaces and the research ive done .

Hugh

hope you other scalers chime in.

 

[hugh hargett]

Bob have you loaded your oberto yet and made an assesment of its transom weight?

 

[BobGutsell]

Nope, but not expecting any surprises, Engine is as far forward as it will go, Flywheel is pretty much level with sponson transoms, fuel tank sits forward of engine and radio box sits tucked to the left and immediately rear of the Engine. Pretty typical stuff really, It's skinned with 1/16 ply and sealed as usually, so weight and C Of G end up pretty much where they fall.

 

[SayMikey]

Hugh is your wing flat on the bottom? Ive never had much luck affecting the ride by messing with this wing

 

[hugh hargett]

Yes mike it is. It has a wing profile but I was worried about too much lift.You think its negligable?

 

[Samuel Hagan JR]

Phil Thomas suggested to someone to flip it over to reduse lift. Instead creating more downforce. On the new scale I'm going to look into that and see what it does to it's characteristics. I'm also curious to how people setup the horizontal wing.

 

[hugh hargett]

Now on phils front canards they are flipped holding her down on the water but unless your scale is light in the butt I dont see why youd want to create downforce in the rear?Admittedly My ss45 is very light in the transom - a good thing im thinking as it requires very little lift out of the prop so you can run close to zero angle and have the prop pushing the boat foward instead of lifting and pushing.

 

[Samuel Hagan JR]

I'm a newb to scale so I might ask a dumb question or 2 but what's the reasoning in creating lift on the rear transom. The way I'm building mine it's going to be light in the transom. I'm building a T-6 by the way.

 

[SayMikey]

All I can say is put it where you like it. Every heat and lap change and dont think you will see enough difference to tell anything.

 

[hugh hargett]

Sam if you read above your post theres my idea on why a light transom is a good thing

Hugh

 

[Samuel Hagan JR]

Gotcha. I didn't see that part. Makes sense to me. This is my first all around build/setup so I've been eating up as much info as possible.

 

[hugh hargett]

All I can say is put it where you like it. Every heat and lap change and dont think you will see enough difference to tell anything.

That could be true I just figure it has to have some affect on a lighter transomed (my own word) boat at speed.. Maybe on a heavy transomed boat it really may take alot of lift and angle to make it happen. In that scenario id try a wing with a more prominent wing profile so I dont have to get to crazy on angle to see some effect.

 

[hugh hargett]

Good night fellas have a good evening IW

later.

Hugh