Here we go again

[Gary]

Ok Im on that downward spiral yet again after a very long positive run. My PT 45 has been running perfect for months. I swaped out motor for a 1530 and it has been perfect with consistant 96-98mph runs. After poking around the Eagle Tree 2Dgps I noticed that the boat was always on a curve towards land, very slight but there. So I flip the boat over and after running a straight edge from off the strut it had a bend to the left. WOW ok thats why she curves slightly to the right. So I figure I can pick up some speed buy making it perfectly straight.WRONG!!! It now will not get on plane, meaning the bow is catching so much air that it will blow over long before top speed . You can watch it keep the nose up off the water and will not settle down to get into the run. Tried some small adjustments to no avail. What the hell did I do? Its almost like I added a ton of AOA the the hull and she wont stick to the water at all. BUT it will in very slight chop. Probably because it is letting air under the hull. Any thoghts?

[NativePaul]

is it possible you raised the strut a little while you were taking the bend out of the strut?

[Gary]

No because I have a small jig that is my stut level is set by on a perfectly flat board. Im begining to think that the slight bend actually put the boat into a very slight turn all the time there by pushing the sponson down. Now I have illiminated that and it wants to raise up all the time. I guess I will have to start all over with strut setings wich really sucks.

[RaceMechaniX]

Gary,

It is common to offset the strut and/or add angle the the strut to counter prop walk. The left you had in the strut was probably helping instead of hurting. Put the left angle back in the strut and test again. I have run up to 5 deg in some SAW combo's to help a boat track straight without rudder.

Tyler

[Gary]

Well at this point the boat runs dead straight so I will try a little more negitive angle and see what happens. Its kind of a pain in the ass as you already know and costly when blow overs happen. Im always told hey just do this and that but batteries and esc's get costly when there dunked and cracked up hulls aswell so I am very carefull with "trial and error". I see your Q-Hydro record... thats fantastic!!!

[RaceMechaniX]

Thanks Gary,

The Q-hydro record was a good feeling and hopefully it will fall again in November with a new boat.

Unforetunately a lot of high speed testing takes trial and error. Keep at it.

Tyler

[Gary]

Well your right on some angle. A little downward and side angle put me almost back to normal. Having an angle pushed down on the left sponson making it settle down right away. Its odd that the prop walk and strut angle wouldnt produce more issues but who knows. I couldnt deal with another blow over LOL. Its amazing how much abuse a PT 45 super sport can withstand I have to say.

On your Q record what size/type hull and what did it come in at race wieght? I am at 13lbs right now.

[RaceMechaniX]

Gary,

The SAW rigger is my own design. It's a three point design with specific SAW sponsons. I never weighed it, but depending on motor and size of battery used it was between 6-7 lbs.

I posted some pics and build comments on Rum Runners: http://www.rumrunnerracing.com/fefor...t=32182&page=2

look at post 43.

Tyler

[Gary]

Thats really well built. Nice job!

Came back from lake again and speeds are at 97-98 on 6 seperate runs and tracks perfectly straight now but still very hard to get bow down to start the run...almost 50-60 yards.... so I am thinking of adding wieght to the tip of the sponson, but I really dont want to make her any more heavy than it is. Any thoughts on what to do? I only need 2-3 mph to hit my goal but again anything I do that the hull dosent like and I could be deep sea diving for it as you already know LOL.

[RaceMechaniX]

Add a little cup to the prop for the speed. Or raise the strut in .010" increments to loosen the front end up more at speed. I would live with the nose gonig up for the first part of the run as long as it flattens out. Are all the wetted surfaces scuffed?

[Gary]

Ok I will add a little cup tonight and give it another try in the morning. The problem with the nose settleing down is the running out of room issue on the run. I will let you know what happens......been raining like a champ here.
Here is a vid of when it used to run around 90 mph you might like . Its early morning so sun glare not to good with video. http://www.youtube.com/watch?v=mvi9KIth-kg

[Gary]

So this is where I am at right now. Added some cup and put a little wieght up front . Moved strutt .20. Boat responded with 99.1 and 99.2mph, two seperate battery packs,opposite directions. Fastest it has ever gone so I am thrilled with that... thanks Tyler and Jay for the help. But its even harder to get on plane now and had a blowover at 55mph trying to get on plane as well.Im so close to 100, so I may try more wieght up front since it didnt bother the speed at all. My permit for the lake runs out today so im under the gun for time.

[RaceMechaniX]

A little more pitch and nothing else.