Experiences w/ a straight turn fin

[Ub Hauled]

On a hydro you have to either have a bend or a hook. hooks work better but require some tuning to get them right. Evert time I have seen someone try a straight fin the boat rides up on the fin and flips over.

I personally do not like hooks on the fins I have, straight (or VERY little bend) is the way to go... one can angle the fin to where it needs to be. The reason is, the hook creates
a good amount of lift and only one side of the hull with lift is not good.

Anyone thats tried a strait or strait angled turn fin please post your results. I wanna see if they'r a good idea or not for this boat.

Good results with a straight angled fin. I like my hulls to slide ever so slightly on turns, I shave the fins until I get the desired slide.

Im kinda looking for feedback from ul-1 owners that have tried different fins, but thank you very much for chiming in.

Tony (Proper Chopper) has a UL with a great fin (IMO), he should be able to tell you about it.

[Raydee]

WOW, i have never had any luck with straight fins. To each his own I guess.

[6S HYDRO]

I personally do not like hooks on the fins I have, straight (or VERY little bend) is the way to go... one can angle the fin to where it needs to be. The reason is, the hook creates
a good amount of lift and only one side of the hull with lift is not good.



Good results with a straight angled fin. I like my hulls to slide ever so slightly on turns, I shave the fins until I get the desired slide.



Tony (Proper Chopper) has a UL with a great fin (IMO), he should be able to tell you about it.

THANKS UB, ILL GIVE TONY A HOLLER

[Grimracer]

6S

How much does your UL-1 weigh RTR?

Where do you have the CG set?

The two questions above are the two most important questions regarding turn fin performance.

Here is why..

Weight and or lack of it or more of it will determine the size of the fin.. for the most part size = slide control.

The CG to far forward of the fin and the boat will push.. to far aft and the boat will hunt. I have found, and race my UL-1, with the fins aft most part set at the CG.

The fin that come with the boat (the black one) is a copy (slightly smaller) then the one I use to sell as is used on my nats winning sport 20. Having said this I have also done a ton of TF testing on the UL-1 and have found a blank copy of the fin thats on the boat (the black one), rolled to a 1.125" radii (bottom 1/3rd) works best for my type of driving.

You can make this out of 1/16" 7075-T6 if you like..

Be warned.. flex is not good... but thicker fins WILL loose MPH.


Grim

[6S HYDRO]

Thanks grim, i am using one 4s 5000 pack placed perpendicular to the motor all the way back. I got way better speed last night as i found that my strut bushing slipped all the way back into the strut and left the prop and shaft wobbleing over a 1/16 of an inch, so i took a small piece of 6mm shrink tubing and placed it over the bushing, and pushed it back into the strut, now it was nice and tight and stayed in place. No more horrible noise at launch and it picked up lots of speed and it actually almost blew over on me for the first time.

But it still does scrub off alot of speed in the corners, is there an adjustment i can do to the curved fin that will make it hold speed in the turns.
Im at work now but i will check the cg at my lunch break. it seemed way to nose heavy with 2 2s packs in the stock position

[Grimracer]

After posting i got to thinking...truth is.. its likey not the turn fin..

I would go to the prop FIRST then the fin to gain cornering speed.

Just a thought.

Grim

[Drag Boat Bob]

After posting i got to thinking...truth is.. its likey not the turn fin..

I would go to the prop FIRST then the fin to gain cornering speed.

Just a thought.

Grim

I also agree with Grim. In my prop testing I found that sharp turns and cavitation go hand and hand.

I didn't think my UL-1 was turning sharp enough, so I moved the servo arm steering rod to the top hole. Woah, did that change the turning... but it shaved a lot of speed in the process. I found that certain props shed more speed in the turns than others.

I did try moving the stock turn fin up to the next hole, but this changes the angle of the bend and did not work well.

All I can say is, try other props also as Grim advises. You may be surprised...

[6S HYDRO]

I have tried a few 40-52/3, l38/63, 42-55. I moved the servo to the top after the first run, i almost hit the bank on the maiden w/ the stock setup and radio adjustment

[detox]

Grim has done a ton of testing the UL-1. I am sure the same goes for his L40X57/3 prop.

...........

[Capt. Crash]

I moved my servo out just one hole and it is perfect. Yes...if I do a full rudder turn it scrubs speed. I learn to turn only as much as needed to keep off land.

I tried the straight fin from Kintec Racing. I only tried it in the all the way down position, but for me...it didn't work out. I was trying to find a solution to the instability after crossing a wake. I love the Kintec stuff and Jan has great service....thanks Jan, but my brief testing took me back to the original fin.

My boat was several MPH slower and I could not keep her on the water no matter where I put the batteries or GPS. It was one blow over after another until I put the orignal fin back on. I haven't tried the new thicker UL-1 fin yet....I see no need.

Y'all have seen the performance I get in my videos...what do you think?

[detox]

I would like to see several UL-1 boats racing together...that would be a cool.


...

[6S HYDRO]

I will be putting up a hopefully 54 mph video up soon guys- got to get back ahold of the camera