New P Sport Hydro 2015!

[Shooter]

D - So I guess what you are saying is that the fin should be at the CG or slightly forward of it. Mine is slightly behind the CG.

[detox]

D - So I guess what you are saying is that the fin should be at the CG or slightly forward of it. Mine is slightly behind the CG.

Yes. Try shifting weight more toward stern (balance hull with finger by hanging at turnfin) I like my hydros to be slightly tail heavy. This will loosen boat up and be faster...watch for blow overs...there is a fine line.

Can you shift the motor back more?



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[Shooter]

Based on my conversation with Terry and this pathetic drawing, wouldn't a fin mounted too forward cause a hook? I know there is more to it, but the major forces are there (force due to acceleration towards the center, and the force that is exhibited on the turn fin).

[detox]

You can use a separate power supply (batteries) for your servo. I know this will add weight, but atleast you can move weight around to test which COG works best.

Moving turn fin will not help strait line speed. You want the hull to run lighter on sponsons without running too wet and tight down straits and in turns. Moving COG more rearward will help.

[T.S.Davis]

Pete, what about a simple end point limitation on your rudder throw. Did you ever look at the rudder throw on my JAE? That thing needs about 5 degrees to turn. Any more and it absolutely will swap ends. Looks like this............it's turning.....little bit more......lit bit....................awww! AAHOOKA!

So because I can't trust myself to just judge that fine line between turning and oh crap! I use the end point adjustment to keep me from doing anything to hurt myself. My Pursuit will hook with too much rudder.

Another way to try that without buying more radio is to just move the pin at the servo closer to the center of the hub. Not sure if you've already done that.

[Shooter]

Yep, I tried reducing the throw by moving the clasp closer to the center of the servo. It works!!!, but then you don't have enough to really bite in and hold lane 1 around the pins at full throttle.

I'm definitely making more of this than I should. The boats run great! Good enough for both of us to place in the top 3 every heat, without a single blowover on rough (6 boats per heat!) water on a windy day! Just need to make a few tweaks. The boats are only 2 weeks old!

[flraptor07]

Yep, I tried reducing the throw by moving the clasp closer to the center of the servo. It works!!!, but then you don't have enough to really bite in and hold lane 1 around the pins at full throttle.

I'm definitely making more of this than I should. The boats run great! Good enough for both of us to place in the top 3 every heat, without a single blowover on rough (6 boats per heat!) water on a windy day! Just need to make a few tweaks. The boats are only 2 weeks old!

Pete you're probably right, that and the fact that you probably just need to get used to driving it.

[detox]

Will adding more weight to stern help rudder and prop bite better?

[Shooter]

Hi guys. It's been nearly a month of playing with these things. Here's what we got:

Pros:
1. Stable in race water. Out of the two boats built, they've taken either a first or second in every heat race (sometimes 6 boats per heat!).
2. No blow-overs. I think the air bleeds are working well!

Cons:
1. They don't like slow speeds and they take awhile to plane, mostly due to the recovery sponson design and the 'drop nose'. However, I think some of this is aiding the 'no blow-overs' in the pro's section, so I'm not willing change anything just yet!
2. The turning is ridiculous. They are practically on rails. Too much steering! We've been playing with several things. I've found two things that work well in taming the steering: a. shifted turn fin 1" towards rear, b. less aggressive fin. Both work well, but it still has me curious what is causing it. Any ideas? The only difference since the first boat is the 3deg dihedral on each sponson. Would making the inside sponson flat help??

[Heath M]

Have you tried turn the steering travel % down on the transmitter? My 31" cat turned great into the corner but hooked bad coming out, turned the the steering down to 50% and now it's perfect.

[Shooter]

Hi Heath. Yes, we've tried turning the travel down as well as moving the position on the servo horn. She still has a wicked hook at the apex of the turn. It's just not smooth/predictable. I caused a major accident in a race a few weeks ago because of it.

So......here's what I've done. The sponson width is about 36mm. Since I had 3° dihedral, the tangent is 1.88mm. That's about the thickness of the ply + sealer and paint. I sanded one end down until the ply met the stringer. The other was untouched. It's flat now on the inside sponson. I put a coat of West Systems on the surface. We'll see how she does on Saturday.

Recall that BOTH boats are doing this with different turn fins, so it has to be something in the geometry. I'm hoping it's not the drop nose!!! That would be tough to fix!!

[Shooter]

BTW. I'm not saying the boat runs bad. It's just difficult to drive. Check out the first turn again if you haven't see it..... HOOK-O-RAMA!!!!

https://www.youtube.com/watch?v=iuqf-BGNr2s

[detox]

I built my hulls so I could change rudder location from left or right side of stern. Maybe mounting rudder on opposite side of current location will help.

Prop splashing water against rudder is not good either....so I use longer prop shaft support so that prop spray does not hit rudder.

[detox]

Or maybe you just need longer rudder?

[Shooter]

These are very good thoughts. I know for a fact that the prop is a tad closer to the rudder on this design when compared to previous (2014 version). Also, the 2014 version had a longer rudder! I'll add both of these to the potential root cause list. Thanks!