Anyone run this boat??? HOR Sea Predator Hydro

[Meniscus]

Here's a picture. Does anyone run one?

hor sea predator.jpg

Specs:

Length: 16" (excludes rudder and strut) 18 1/2" with strut and drive
Beam: 7 1/8"


All input welcome

[785boats]

I run the 33" one. Bought it from R/C Boatbitz here in Australia.
Still having problems with skipping in the turns & hopping up the straights.

The video is its test run with an 8Xl on 4s with an X640 prop.

http://www.youtube.com/watch?v=q4NZuRk9tR4

Cheers.
Paul.

[Meniscus]

Paul, I was really hoping you would see this and share your setup. I didn't realize that there were different sizes available and 33" is a pretty big size difference.

Do you run a turn fin? Also, have you GPS'd? I'm really curious about how the aerodynamics effect the attitude of the boat on the water. For reference to the video, could you take a picture of the strut angle?

Last question, sorry for so many, do you know anyone that runs the smaller one?

[785boats]

Hi Ben.
It might be easier if you have a read through this & then I can clear up any questions you have.

http://www.rcgroups.com/forums/showthread.php?t=1147418

But to answer your immediate questions...
Yes I made a turn fin.
GPS reading was 45 mph I think on one of the 5 lap runs.
One of the guys at our club has the smaller one & it was pretty damn quick. Here's a cute pic of them together for comparison

Here it is with a 7Xl. Gives you more of an idea on the skipping & hopping & chine walk. As you'll read in the R/C groups thread I've had to add weights in the sponsons & have the battery right up the front to balance the hull.
There is very little adjustment for angle or height with the setup on these boats & I haven't pulled the whole assembly off yet to drill & file it to increase the adjustments , as I intend to do. They are also those square drive type of setup which is a pain. Perhaps a complete new Hydro assembly is the best fix & with an offset rudder.
And as you'll read the water pickup below the strut pumped water up the shaft into the boat. The guy with the small one had exactly the same problem.

http://www.youtube.com/watch?v=t1wcxlyQD7Q&feature=player_embedded

Anyhow have a read through the thread & hit me with all the questions you like.
Cheers.
Paul.

[Meniscus]

Paul, that thread sheds some light on the subject for sure.

That's a great picture of the two sizes together. I like that!

Have you had the chance to try any high lift props or set the strut deeper in the water? Now I'm no expert and admittedly, I don't have the most experience, but I think your suspicions regarding the inline hardware are likely true. If you think about offset hardware, keep in mind for hydros at least, you want the leading edge of the rudder to have clean water. This means you don't want it back where it gets in the prop thrust cone. If the rudder does encounter prop wash or other water turbulence, then the rudder will have to be that much longer to get to clean water. Of course this creates drag.

My recommendation before you go to too much trouble, pull off the strut, file it so that you can lower the strut more than what the stock allows you to and try a high lift prop, say V937/3. My main concern is the AOA of the sponsons. Can you post a profile picture of the sponsons on a flat table? Also, have you looked closely to see if the smaller brother has the same AOA?

[MarkF]

The more lift a prop has the more it will want to hop. Since you dont have much strut angle to play with I would try running a low lift prop like a 440 or 445 prop. Cupping the tips of your 640 will help with the hop as well.

Mark

[Meniscus]

The more lift a prop has the more it will want to hop. Since you dont have much strut angle to play with I would try running a low lift prop like a 440 or 445 prop. Cupping the tips of your 640 will help with the hop as well.

Mark

Mark, this does make sense. I was looking at the ride attitude on the water before addressing the hop and also suggesting another approach, at least to try and see how it responds.

Paul, Mark knows far more than I do. I'd take his suggestions before mine, any day.

[785boats]

Ben.
I did actually try my 1640 prop which is a higher lift prop but it made no difference.
I should get to it & make the adjustments to the strut assembly, but I've been playing around with other projects & not giving this one the attention it deserves. I'm sure you know how it is.
But I did buy some styrene sheet to make some ride pads just the other day. The edges of all four sponsons are very rounded.
Just took a few pics for ya. Hope they help. Not sure if the smaller one is exactly the same.

Mark.
Thanks for the advice. I've got a K440 & K442. I'll give them a try too.
When I mentioned "chine walk" it's more the lifting of the left sponson. The right one stays planted, I think probably because of the hooked turn fin. The left one lifts even more if I add some left rudder under power. I'm talking small corrective rudder if I've turned too much coming out of a corner & need to veer left slightly to get outside the first buoy at the next corner.
Does this suggest a typical setup problem to you? Or anyone?
Cheers.
Paul.

[Meniscus]

To me, the strut looks fairly low enough, although you could try it lower. Do you have enough adjustment to make the strut angle more neutral?

[MarkF]

On some of my hydros I use to put the battery in the left sponson to get it to stay planted.
Try shifting some weight over to the left side. Also put a little left into the strut.

Mark

[785boats]

Ben.
That is it's lowest adjustment and as level as it will go. Hence the need to pull it apart to do a bit of 'machining' with drill & files.
I was hoping that, that setting, would lift the rear sponsons off the water a bit because when that happens the strut is then level with the table (waterline).
The only way to put more neutral angle into the strut (with the adjustments available) is to raise the strut. Then the tail seems to drag in the water & it still skips & runs slower. If I have time I'll pull it apart tonight & see what I can do with it.

Mark.
I do place the battery over to the side as you suggest but the sponson still lifts.
Thanks for the tip on angling the strut to the left a bit. I'll give that a go too.

Thanks for your help guys. As this is my first Hydro, it's a big learning curve for me.
Sorry if all this has jacked your original thread Ben, but it has been a great help.
All the best.
Paul.

[Meniscus]

You haven't hijacked the thread. This is the reason why I created it! You're encouraged to continue!!!

I'm wondering if this can be attributed to torque roll or not offsetting the driveline. Mark's suggestion will definitely help. I've had to do that before. I'm sure that he can also give you more input based on the model's attitude on the water.

You say learning curve? And you've been able to get a canard running? I'd say you're either really lucky or you are understating your abilities.

[785boats]

Thanks Ben.
This thread, & the info from you & Mark, have certainly given me the inspiration to put a motor back in it, make the adjustments & give it another run.
I found this video on the smaller version. Speed looks similar to the one at our club.

http://www.youtube.com/watch?v=aLvtJQ743Rg&feature=related

All the best.
Paul.