Need Help Mini Hydro

[BakedMopar]

Hello I have recently acquired Diegoboys Mini Hydro and need some help tuning this thing. I have no hydro experience so go easy. I got the boat to run a straight line well it just wont turn. You have to really creep through the corners. It seems to be stuffing the left side in the water at speed in the turns. It currently has no turn fin. Need some advise on placement, size etc on the fin.

Heres the current setup.

Total lenth is 17.5"
C.O.G. is at 2 7/8" behind the rear of the front sponson.

Here are some pictures. The last ones are where I think the turn fin should be. Due to the size of the hull would it be okay to mount on the hull and not the sponson? Its tight in there and the ride pad is way in. Should I space it out or should I run it as close to the hull if it's okay to mount it there?


Thanks George

[RandyatBBY]

he turn fin should not need to be more than 3/4 inch below the ride pad on that size of the boat. It will make the boat turn. The CG should be in the center of the turn fin. I put the CG about 1.25 inches behind the rear of the ride pad. If the CG can not be moved then move the turn fin back.

[BakedMopar]

Yes the battery is all the way up front. Could I mount the fin to the hull instead of the sponson?

[RandyatBBY]

Yes the battery is all the way up front. Could I mount the fin to the hull instead of the sponson?

No need I quote you said "C.O.G. is at 2 7/8" behind the rear of the front sponson"
So you put the turn fin in the middle of the COG.

[BakedMopar]

Okay here is a picture of the middle of the turn fin would be at COG.

[RandyatBBY]

as far as placement looks good but no more than 3/4 below the bottom of the ride pad. Like in the picture below.

[BakedMopar]

Okay cool. My only concern is mounting a bracket to the sponson. It seems really thin and Is a pain in the ass to reach in there. That is why I ask if it okay to mount from the side of the hull.

[BakedMopar]

So I went out to run it again today. I tried a V935 that was cut down to 32mm with this prop it was very hard to get on plane. When it did it scooted though. What kind of adjustments do I have to make to get this prop up on plane easier.

[Jesse J]

maybe a touch deeper strut.

[BakedMopar]

Leave the angle the same? I am trying to convert some short video will post them up later.

[JimClark]

show pictures of the inside setup.

[BakedMopar]

This is how the inside is setup. The speed control is in the Port side sponson and the reciever is on the starboard side. It was originally setup with the speed control on the starboard side but the torque roll was really bad.

[BakedMopar]

Here is what I did for the turn fin mount. It look good to me. What do you thinnk? The fin will be trimmed at the last bend.

[BakedMopar]

Here is a short video. It shows how it flips in the turns.

[JimClark]

hw much servo travel do you have set up plus you are taking a very tight turn

[Jesse J]

How much hook on the fin you got? On these micros, I have noticed that it is a balance between torque roll and enough weight on the inside (starboard) to keep from flipping. It looked like something caught and flipped you over; thus need to see the angle of your turn fin - please post a pic of the underneath so we can see just what angle your turn fin is set.

[BakedMopar]

In that video there was no turn fin. The rudder has about 30 degrees of throw.

[Jesse J]

How many times has it flipped like that? and agree tight turns can do this to you. A turn fin will definitely help this, especially with some hook in it.

[BakedMopar]

It flips a lot. Almost every other turn. I will try to get you some pics of the turn fin.

[Rumdog]

Agreed, less rudder throw, longer sweeping turns and the turn fin is a must!!

[JimClark]

Before I would mess with the turn fin I would add weight to the nose to drastically change the CG seems like the CG is way back too far

[BakedMopar]

Here are some better shots of the fin mounted and trimmed. I turned down the rudder throw to about 20 degrees. I am going down to run it now I will get back and let you know how it did.


Thanks for the help guys!

[BakedMopar]

I'll take some weight with me. Where should cog be?

[RandyatBBY]

Have you ran it sence you put the fin on? I run that type of fin in that location with a little more curl to hold in the cornor, turn right only at full speed and let off power to turn left. Turn fin should be stright up and down.

[RandyatBBY]

I'll take some weight with me. Where should cog be?

\
If you put the CG foward you will need to move the turn fin foward.

[BakedMopar]

Okay after a whole buch of swimming er testing, I think it runs much better. I had changed the layout of the electronics. I put the speed control back to the starboard side. I added 3 oz of weight to the port sponson and 2 1/2 oz in the middle. This was the last and best setup so far. It lost a some speed but was much more stable. I didn't have a camera person so I will try to get some later. I did not play with the fin at all with the exception of moving it's center in line with cog. All my testing today was with weight.


Thanks,
George

[Jesse J]

I would think on one that size COG shouldn't be more than 1" back from trailing edge of sponson. Where is it now?

Did it flip any this time?

[BakedMopar]

Okay here is a detailed breakdown of my testing. Plaese note that everything happens fast and my eyes aren't the best so this is what I observed.

1st run: Turn fin added only. Still flipped.

2nd run: Added 3oz. to starboard side. Same thing.

3rd run: Added 1 1/2oz plus the 3oz. from run #2. Seamed to bury the nose hard. I say that because I tend to see a lot of prop from the back.

4th run: Took everything out and remounted the electronics. Put the ESC on the starboard side and the receiver on the port side. I also took out all of the weights. Port side was really light and had bad sponson hop. Now it seemed that the fin was digging in and throwing the boat over.

5th run: Added 3oz weight to the port sponson. Calmed the hop down a little but turn much better. Flipped only once but I think it was from a cross wake.

6th run: Added 2 1/2 oz to the center (in the nose). Ran flat and turned even better. I did not flip it on this run. I still ease off the throttle a little but not much. I'd say about 85-90% on the throttle. This was the best it ever ran overall.


It lost a little speed with the fin but it's probably due to the extra drag. I did not play with any other settings other than those that are listed. The center of gravity is still way behind of what is recomended. When you say trailing edge is that where I am measuring from? This is a scale of the whole boat.




Thanks for all the help,
George

[JimClark]

What motor and batteries?

[BakedMopar]

Motor is a Feiigao 380 8L. Batteries are Turnigy 3s 2200 30c. Prop that was run today was a Octura X632.