Cavatation??

[M.M.]

Well this past weekend was the maiden voyage of my DF copy. I was happy with it but there was one major problem. I could not get the boat to "bite" the water. It would not get on plane so i had to push it, once it was going it was alright but with more prop i feel it would be mucho faster. So do i need more diameter or pitch or both?

What would be some good cheap props just to test with for now? Preferably plastic just untill i find what works well, then ill get a S&B.

The boat is a 25" mono, powered by a 2881kv 380l sized motor. It also has a turnigy 120A speed controller with two 3s wired in parallel. None of the electronics were even warm after the run either.

[M.M.]

Well i am thinking of trying an octura x435, and x632

anyone?

[M.M.]

Nobody has any prop suggestions??

[Diegoboy]

How about a picture of the business end of your boat. There may be more than just a prop issue. It'll help get more participation when we can get a better idea of the situation.

[M.M.]

here ya go:

[Jesse J]

what prop were you using that caused the prob? That motor seems a bit small for that hull too. I would go with a 540L can if possible, or try 435, 438 and 440. I bet a 440 will get you out of the hole.

How were speeds once up?

[M.M.]

The prop i beleive is a 430, and when it was trying to get on plane it would just barely move, but you could hear the motor revving like crazy. Yes i know, but i want to run his motor till it dies then i will probably get a 13xl. Once i pushed it and it got up on plane it moved ok, but seemed to top out fast. So i think i definently need some more prop.

So for testing how would a x435, and x632 work?

[Punisher 67]

This is just an observation but your tabs look to be angled down , Check that . Also we were having issues getting more speed out of a DF29 so when Ken (KSM2001) REMOVED the tabs altogether his gain was almost 20 more miles per hour with a slightly larger prop . Ken is getting 57mph out of his DF29

[Diegoboy]

...see? A picture is worth 1000 words.

[Meniscus]

Depending on the manufacturer of the 380L, you could also try advancing the timing up a notch after you try the suggestions above.

Personally, for the size hull, I'd try an x432 if you have one, but I admit, I don't have any experience with this hull, rather I have read a lot about hulls in this range and many folks have success with that prop. However, with the lower KV motor, the x432 may still be small.

[HOTWATER]

The strut and drive dog are too close together...you need to have about an 1/8" gap between them. When the motor spools up, the flex cable will get tighter and the drive dog will be drawn into the strut! Whith that note...you should check and make sure your drive dog is still tite and not spinning on the stubshaft...did you grind down a flat spot on the shaft for the drive dog grub screw to bite on?

Also, you should put a zip tie or a peice of fuel tubing around that water line/ fitting on your rudder...

-Kent

[Meniscus]

The strut and drive dog are too close together...

Good call Kent, I didn't even notice that. I was too busy looking at the other hardware and the angle of the trim tabs.

They also have spring loaded fuel line clamps that Diego found at the LHS. He may be able to provide the manufacturer's name. I'm thinking it's maybe Dubro, but I don't remember off hand.

Ben

[M.M.]

The way my set up works is that the flex cable is squared on the end, which then slides into the propshaft. So when the flexi cable shirinks it slides within the coupling. (kind of hard to explain, but i know that its not that)

I beleive that it is a 1/8 shaft so the 435 seems to be a good choice so far, and i was thinking a 632 would also give me some more pitch. This way i can figure out if i need more diameter or pitch.

So what is the view on trim tabs? Are they neccesarry? Should i remove them?

[HOTWATER]

Good call Kent, I didn't even notice that. I was too busy looking at the other hardware and the angle of the trim tabs.

They also have spring loaded fuel line clamps that Diego found at the LHS. He may be able to provide the manufacturer's name. I'm thinking it's maybe Dubro, but I don't remember off hand.

Ben

Hey Ben!

Those spring clamps would be great to have! LMK where Danny found them...

Ahh...square drive...not sure on that...but I would still check out that drive dog...Just to make sure it's not spinning on the shaft...Just trying to help on some small thing that can make a world of difference...

Also, I would keep the tabs...they will be a huge help later in dialing in your setup...

-Kent

[M.M.]

Yes there is a notch that was ground into the propshaft so that the drive dor will not spin. However, one problem i was having was the flexi cable spining inside of the coupler, but some wrenches took care of that

How should the strut be adjusted? for example when should i move the angle up or down?