PDA

View Full Version : scale hydro turn fin question.



T3Merc
04-17-2014, 07:54 PM
I picked up a never used pro boat llumar hydro for next to nothing and after running just once tore it down for a major
rework. Question is I changed to a hooked turn fin so my angle is critical and what is a good starting angle.? Do I string a line from the sponson to the bottom of strut or to the rear sponson.? About a .625 difference at the rear.
thanks in advance.!

Dago

Luck as a Constant
04-17-2014, 07:56 PM
im not sure i understand what you mean....

siberianhusky
04-18-2014, 08:37 AM
I've always installed them straight up and down as far to the outside of the sponson as possible, adjust the caster according to what the boat actually wants, I always start out with as close to 0 as possible, if the sponson digs in tilt the turn fin forwards a little, if it rides up out of the water tilt the leading edge down a little bit to suck the sponson down onto the water.
And parallel to the hull centreline. Although with testing this may change a very little bit if the hull isn't square, had this happen with a scratch built hydro once.
I'm not really sure I entirely understand what you are asking either.
Never measured to the strut or a rear sponson, not exactly sure what knowing that number would accomplish. Also no idea what you mean by 0.625 difference, what measurement is this?
LOL wondering if you know some secret I don't about hydro setup!

T3Merc
04-18-2014, 02:13 PM
Sorry yes its hard to explain.
my turn fin is hooked so not only has to
be straight down the center line but also parallel
to the running surface. If not it will pull down or push
up on that sponson.
my question is on these big scale boats what is the running surface. Is it a line from the bottom of the front sponson to the bottom of the strut or to the bottom of the rear sponson. Just looking for a starting point.
thanks.

dago

siberianhusky
04-18-2014, 06:44 PM
I get you now. Bottom of front sponson to bottom of strut.
It will be a process getting it dialed in, moving the strut up or down will change the angle of attack of the hull changing the turnfin angle again......Readjust and try again.
Each adjustment has an effect on all the other adjustments, I try to measure everything and keep notes so I don't have to start from scratch if I tear down a hull for paint or something.
Cheers and have fun!

T3Merc
04-18-2014, 06:53 PM
Thank you.!
Thats my starting point. Cool.

dago.