Hydro pros..........need help, PLEASE!!

[Make-a-Wake]

This is my first Hydro(miss Elam 1/12) after many Vees and i am having some trouble getting her to run well after several times out. A hydro is surely a different hull from what im used too, but i loved the look and wanted one.

Anyways, she has her moments of glory, but mostly not. Any and all suggestions are very appreciated as i am feeling a bit "beaten" by her.

I have been told to use an "M" prop, and to give the prop some positive angle. Running an x642.

Only got to 3/4 throttle once at about 1:14..........ran good right there til i slowed.
Thanks again in advance...............

The madness begins at 0:27

http://www.youtube.com/watch?v=VNvg19xML8M

[Make-a-Wake]

Just realized i posted in "building"............sorry mods. ..........i did build it though..........

[domwilson]

Try raising the prop till it's level with the ride pads. That would be a good place to start. Also run the prop level.
Where is your COG? Jesse on this forum as well as Darin have good advice on setting these up.

[domwilson]

Der...Didn't see the pic for the COG. Try moving it forward to 1 1/2" behind the sponsons.

[Jesse J]

Hey Carl, based on how she ran in the first half, I would suspect the turn fin came loose. This has happened to me and once that goes its like loosing a tie rod in a car.... That turn fin is your best friend and worst enemy. make sure everything is tight.

This is still pretty stock? do what ever you can to get weight forward, but that isn't your wigglywobbly problem. Check for loose stuff then if nothing loose come back and report. In the mean time I will study your pics in OP.

J

[Jesse J]

She looked real good at first. As for COG, you are a bit back, but that will only really become a problem at higher speeds. I think the strut is stock low like that to compensate some for the rearward COG. My buddies is over 3" back... I need to make him leave it in my shop so I can do some doctoring (probably what yours needs as well).

Darin added adhesive weights to the front and it supposedly helped out.

Last run on my avatar hydro, the whole strut came loose and was floppin like a fish held by its tail (I should post the poor mangled prop - its a trophy).

I was also told by a very credible source that cupping the prop some will help tame down that tail end.

If all else fails, you may need to redo the stuffing tube so you can raise up your strut some more. mine is probably about where Dom suggested and is pretty standard starting place. Remember, that prop is in equilibrium when riding at the surface and will try to achieve that. so if you have it too deep, it will keep popping up the back end. You will be perfect when you have a touch of hop, but it settles into the turn nicely.

Don't get discouraged, hydros are the hardest to tune, many variables - change one at a time.

[Make-a-Wake]

Thanks guys............................the cog is as far forward as i can get it.

As for the turn fin..............when it comes in, i dont notice it at a different angle..........seems tight. I think i'll try it tomorrow without the turn fin and go easy on corners while testing. Is the prop too big.........is it torquing the hull and lifting the left sponson?

I had a 5 ounce weight in the front left side and it didnt really help. Hmmmmmmmmm?

[Jesse J]

DO NOT TAKE OFF THE TURN FIN - it will not turn at all!

Try stuffing the ESC into the cockpit and the batteries into the sponsons. The more I think about it, the more I want to get your strut up higher. How much can you raise it? you may need to bend the stuffing tube (very gently as it is cheap brass and will break pretty easily). I cut mine off flush with hull inside and out then retrofitted it for .078" wire drive. But that should not really be done unless you are ready for the "overhaul".

These are the best looking hulls out there, but at a price. To get em to perform, you gotta tear into em.

oh, and the prop is perfect! you are not torquing the hull, it is sponson walking, frustrating little stunt they do when the back end is bouncing all around.

[Make-a-Wake]

OK............wont take the fin off. The strut is actually higher than it is stock already from what i've seen.

"you are not torquing the hull, it is sponson walking, frustrating little stunt they do when the back end is bouncing all around."

OK, so whats the cause of this? Back end too high as you have said the strut needs to be higher? I am at the end of the strut adjustment so i guess i'll ream out the slot for more travel up.

These suckers are tough!

[Darin Jordan]

It looks to me like it's fighting the turn fin. I think if you find my "Race Prep" thread for this boat, you'll should see an example pic of the turn fin I fabbed for mine. You can try rotating the fin forward or aft a little. I looks like it's pulling DOWN on the sponson, so rotating it forward a tad will eliminate that to a degree. I was never able to really make the stock fin work, so I replaced it.

This hull has a tendency to do this walking at speeds exceeding 45-mph when the water gets choppy, but you should be able to get it better than it is. Little adjustments.

[Make-a-Wake]

Thanks Darin! I was suspecting the turn fin myself, kinda why i wanted to run it without it, Jesse mentioned it wouldnt turn at all though.............with the cupping, it has to be perfectly aligned or it seems that it would pull down or push up. Gonna check your "Race prep" thread. I have been scouring your posts on the Elam.............even found the part about extra weight..........i think my COG is pretty close............?

[Darin Jordan]

To test the fin theory... go ahead and take it off and run the boat. You won't be able to turn very well, but you'll be able to test it for straight-line stability. Just slow down for the turns.... WAY down...

[Make-a-Wake]

Well................off with the fin then!

I'll report back later today.....thanks again!

[befu]

Turn fin

I have tested this before also by replacing a curved turn fin with a small flat one. It will still help it turn slowly, but will not cause a digging or lifting in the straights.
Just make sure it is straight up and down.

Brian

[detox]

Here's Darin's fin.

I've made a new turn fin. Just about 1/4" longer, and a longer chord length to give it more area. It's made from .060" 7075 T6, and has two slight bends in it to hook it at the bottom, one 1/2" up and the second 1" up... Not quite as hooked as the stock one. Sharpened and drilled up. Should provide a bit more control in the corners when the water gets "racey".