hydoplane design engineers ?

[afrhydro]

i got a get this boat to quit flying so high
i was thinking of adding some smaller sponson to the outside corners of the afterplane like the unlimitieds have kinda
or can this just be done as simiple as adding some reverse air traps
i posted some pictures for references

thanks for any help

Pretty boat. Always a balance between taking off and stuffing, I'd take the former. Doesn't do you much good, but I believe the F1 guys are all going with more rounded, mor controllable front ends so they aren't so touchy. I'm not a hydro expert, as few are (but was around them a lot when I was young), and it's difficult to give advice that, if it's wrong, could cause a serious accident. Can you feel it start to take off and have to back off on the throttle? Is there any type of control surface on the leading edge?

[Tcubed]

Isn't the whole point to just barely touch the water?

What are you worried about?

If it is control then i understand since these types of boat are extremely unstable aerodynamically and when at speed are essentially ekranoplanes with the weight way too far back.

For this i would say that the best approach is to accept the fact that it is essentially a wannabe airplane and work the aerodynamics of it.

There are many options if you are not restricted by race rules. the main thing is to get your aerodynamic center over , or aft of your CG. After that it is a matter of trim.

If you are bound by race rules it gets very complicated indeed.

This is only a quick reply and may not be relevant to what you have in mind.....

[afrhydro]

yea its flying its very managable @ 70 mph anything more and ill needs a set of wings and flaps
which im not aposed to trying anyhow
i did start to make a canard for the front
the sky,s the limit for me on shape or anything this is just my boat i use to go riding in the river
no rules apply

[Tcubed]

No rules, great!!

No canard, that moves your aerodynamic center forward.

You need horizontal surface way aft and have it adjustable a few degrees.

For absolute maximum speed, control is not a luxury , it a requisite.
When you wipe out your speed goes to zero , maybe even permanently.

[afrhydro]

that maybe the only way im going to gain the control and stability to go any faster is put the whole same wing on it like the unlimiteds have
in the origanl design it had a rear wing designed into it but i scraped it

[Tcubed]

Yeah except i would put it a lot further back still.

You could also try paring away some horizontal surfaces at the front. It seems like you have plenty enough lift already.

Although i would have to see better images or better yet , the plans, to be able to comment further in an intelligent way.

[afrhydro]

all kinds of lift is right i bet i could put a prop on the front and the back it would fly

the center section has a wing angle of a 13" center line on entry and the sponsons are 13" deep at the deepest part shes 15'3" down the center the sponsons are 8' long cog is off center by 2' aft {empty hull cog)
48" wide tunnel
those air traps are 4' sponsons are 6 inches deep
um
center section has a 6 " flat pad or knife bottom with a 15* dead rise
10' wide 1 1/2 deep air slots stepped
sponsors are also stepped

i can take more pictures on monday or draw it out for you from memory

[Tcubed]

All right yeah, pics (from straight above , front, details, etc), exact weight, your weight, more numbers....
Then i can give you my best opinion on reasonable aerodynamic solutions.

[afrhydro]

that pic is on the shop putor i cant find it right yet if i posted it some where
this is all i have of the front from above
im 185 lbs the boats 1200lbs with 8 gallons of fuel aft battery aft

the wing in the picture was just sitting on there in mock up
the other picks shows the wing struts on a 80 * angle
this time i think that should be vertical and swept way aft maybe cl on the crank on the motor
ill add the pic if i find it from the top

[afrhydro]

these pic,s are from before the dash was moved up and the struts where removed

[Dan Ellison]

Are you trying to carry the boat on the transom ? or trying to run it as a hydroplane on the front sponsons and prop? It looks like from the pictures it's a tail dragger.Can you move weight forward? Neg on the trim or drop the motor down to take some angle of attack out. A prop with alot of transom lift. Just a few thoughts. Our 21' 3200lb fuel hull balances at about 40% front 60% rear and only rides on 7" pads.

[afrhydro]

yes sir dan i would like to fly the boat on just the prop and maybe a hint of the pad on the bottom with out blowing over
in the photos i had my trim pin in so i could go no more then 3 *negative trim
i can add more negative by moving the pin in for 6 * etc
i have some new props to test to do here as soon as the weather warms a bit and the $ is there
14x4x26 rh dewald cleaver2.01 gears and a 14x3x24 dewald cleaver and a mercurt et 14x24 touque hub i also have two other 14x24 mercury cleavers
the test photos was during a prop test with a 14x22 mercury et copy

Battery could go more forward as a start. Fuel maybe. I wouldn't put a wing on this pretty boat unless necessary, tho I am not an engineer.

[afrhydro]

Originally Posted by mark775

Battery could go more forward as a start. Fuel maybe. I wouldn't put a wing on this pretty boat unless necessary, tho I am not an engineer.

with a little effort i could move both to the front would moving weight alone show more speed or do the same thing with the air traps i spoke of in the first post

i would think if weight distrubution was going to show more top end that as the fuel burns off the top end speed would get better