back on the ole red hydro handeling issues ?.s

[afrhydro]

hey guys see if you think im on track here
hydoplane design engineers ?
what you guys think about cutting the pickle back straight across would this reduce the lift ?
and or cutting release slots in the top of the tunnel allowing the air to escape out the center section ahead of the cockpit ??
old topic but i had this boat layed up for a while and returned to it to figure it out
there has been some more mods on the bottom it now has wedges / reverse air traps 4ft long 0 to 3.5 and some fins on the sponson steps closing in the sides both these mods improved hadeling but added no speed

hydroplane design additions

[Jimboat]

hi scott - call me anytime...

[afrhydro]

calling now ileft a few messages

[Jimboat]

Originally Posted by afrhydro

calling now ileft a few messages

i will give you another call.

[afrhydro]

http://www.youtube.com/watch?v=ZDDWj...1&feature=plcp
it was a little better with more negative trim angle

[afrhydro]

hey jim when you watch this video see if you can tell how that water is coming off the sponson then it gets in the wind stream and fly up faster and hits me right in the face
this boat has always done that over the waves

[Jimboat]

scott - i watched the videos....it's hard to tell about the spray from that angle. could be just the details of the sponson at the fore location. maybe you can email me a photo/picture of the sponson shape in that area. i see a bit of chine-walk there too.

call me anytime to talk more on it, scott.

[afrhydro]

will do jim from what i can see in my minds eye is the steep angle up that high on the sponson is just so that it throws the water forward then the air brings it right at me
i think a simple step up higher just might kick back down for me

[afrhydro]

oh and the extra trim angle was nice till it started that sponson walk and dipped that left front sponson in
that was 7 ill try 5 next time and i might try 7 again with a round ear 30 hooter prop i got

[IMP-ish]

Good looking boat afrhydro.

Is your boat a one-off design or a modified boat I should be able to recognize?

[afrhydro]

thanks man its a one off thats a old old picture its been highly modified sence that shot

[afrhydro]

and i thought i would add what i think is the problem

as the speed reaches 70 + the water is planing to far forward of the intended foot print area and as it moves of of that zone the angle increases and it makes it sponson walk / dig and dart around

[tunnels]

Have you tryed to adjust the motor trim one way or the other . It sounds like the boat is at the stage of just being airborne but its out of balance !!
Just behind the back of the sponsons is there a plywood panel partly blocking the escape of air out the sides of the tunnel just before the air is forced under the after end of the hull .
Remember you are in the zone of Aero dynamics at 70 mph . you have done the change from hydro dynamics to Aero dynamics and well in the phase of surface effect and squash . as your speed increases you will be flying !!! You need to get good clear pictures and video so you are able to still frame and see what happening . Its a good idea also to get a bright coloured stick on tape and set it level line on the side of the coaming so its able to be seen on a picture or video . you boat has a problem just need to find the cause of it and understand why its doing what it doing .

[afrhydro]

yea no one got any pics last two times out
funny thing is if i add a rider the tail pops and its fine at 68/70 at three degrees negative to 0 trim angle
i run it alone and it does a 180 and tail drags with high flight risk
so increased the negative trim and it went back to the same problem with the sponsons
the foot print is just not there its to small to short and to steep
as best i can tell from the seat

[tunnels]

Hydros lift their tail with a inboard so it rides on just the tips of the two sponsons . with the tail hanging loose . hanging the tail is done by the propeller liftinthe back plus the rudder is normally long and digs deep so has to be incredibly strong . Ok now you have a out board and completel changed the concept and balance of the thing so a out board hydro must be a sightly different design .So which one do you have ?? With boats if you change just one thing everything else changes as well . From sitting in the seat you can only feel whats happening .if the boat rode better with a passenger then it need weight some where . You got to get video and clear pictures at all kinds different angles and trim settings. other wise you just chasing your tail going round andround and getting no where .