Why no aerodynamic control/stabilizer surfaces on high speed cats?

AFR,

I can relate...Just my two cents. Get a good old not bucketing helmet, and a race jacket! Even @ 70 you should be wearing some gear.

The cleaver has little bow lift and you are most likely just too slow to fly...so a rounded ear with some cup helps you with the 115. Airs the boat out more without the trim. When you go to the bigger vee motor only use a cleaver unless you absolutely still need the bow lift. I would NOT even try a big ear with bow lift unless the V6 is a turd.

When you get her flyin she will be fastest with negative trim. If the speed is too high for the hull and you get too negative (all depending on cg) she will lift off when you chop the throttle...so back off easy and use some steering to rock her enough to dump air and touch the pads too slow her down.

You probably already know all this but I feel smart now

p.s. charge more for what you do...it's only fair...you need your share.


NAD

 

thanks man
i got the life line and i been trying to hook the tether more
every time i think of it i hook it anyways

i dont think the v motor is going to be able to do anything but negative trim

it has been good to learn with the 115 or it would have been splinter,s already
more than a few times i have had issues and learned what not to do

charge more the people dont want to pay me what i am worth now
most of them have no idea who i even am
i had to move out of the keys it got to expensive to live there anymore
but i got twice what i get now for the same jobs and that works both ways
you know what I'm saying it is just about survival anymore these days
i had a wait list and ten boats on deck just about all the time
now i keep right up

 

I agree that one autogyro control would not be enough. A different system would be needed for every moment (pitch,yaw,roll,etc.).Maybe some hover height sensors to govern the throttles while on the wick.Think fly-by-wire for military aircraft and RC jets, some of which also use gyros for stability.So much technology so little time.I'm sorry to jump topics, but who's hydro, any plans available?

 

i hear ya so many options its not even funny
but the only true test is on the water in real time
i designed that hydro all myself with input from the teams mentioned
and got the bugs worked out so to speak
i been looking into a front wing for a while now and the plan was to have a rear wing as well but i would have them fixed with a manual adjustment only
you get to much to play with and that could cause trouble as well
IMO
i have to get some number,s to my buddy in canada (jimboat) so at least i know what the program will say the limit is


oh by the way i finally figured out a name for the boat

it is
the WHY KNOT

 

oh i have quite a bit of wing set up experience

 

auto sensing and flight control

There are many kinds of Gyro's these days... Very important factor's in using aero types would be things like sampling rate and error. If the frequency is 60hz then compensation would only be per second. Not fast enough considering the boat would have already covered a lot of distance between samples. Another would be gyroscopic error which is a problem for a fast boats where inches count for pitch and roll. An aircraft does not care much if it ended up 20 feet higher or lower after an auto control compensated to level things out, but even 2 inches could be devastating to a boat. There are gyro's today that are better...such as a laser gyro...fiber optic gyro...or possibly a quantum gyro. Sampling rates could be very high if the gyro is very accurate and not disturbed by error, shock loads and so on and possibly do the trick.

Sheesh it's hard enough to build a 200 mph hull for calm water, not to mention a 400 mph craft. Do you think American Challenge or Quicksliver had any idea what they where setting out to do when they started talking about it?

Last i heard they are still talking?

I think blood and guts are here for a little longer yet!

NAD

 

Vertocal Stabilizers

Those wing end plates are a good example of how a vertical stabilizer can generate an anti-roll force when a vehicle is sliding sideways through a turn.

 

i just copied and pasted some info here
this is a subject with no ending to it



Sprint Car wings act like upside down aircraft wings, creating downforce instead of lift. A wing generates downforce due to the air pressure differential between the top and bottom surfaces of the wing. Due to the shape and angle of attack of the wing the air below the wing travels faster than that above, meaning that its air pressure will be lower. The speed of the air above the wing is either not changed or slowed by the shape of the wing, meaning the pressure of the air above the wing is higher than the air flowing under the wing. The downforce is created as the high pressure area on top of the wing is drawn to the low pressure area under the wing forcing the wing down. As the speed of the wing moving through the air is increased, so is the downforce.
Wing Angle
The wing angle is important for it to work efficiently. As the wing angle is increased so is the downforce, however this also increases the aerodynamic drag. Too much drag will reduce the car’s speed down long straights, this is not as much of a concern on smaller or slick race tracks. Too much wing angle can also cause what is known as wing stall, this is where the extreme angle of the wing can cause the air to separate on the wing surface, creating turbulence. This turbulence will reduce the amount of downforce and increase drag. A top wing angle of around 22-24 degrees is a good starting point when trying to find the optimum angle.

Tip Plates
Tip Plates or Side Boards are used on Sprint Car wings to ensure that the high air pressure area moving over the top surface of the wing is not allowed to spill over the sides into the low pressure area under the wing and vice versa. If this is allowed to occur it produces a whirling vortex which affects the efficiency of the wing by reducing downforce, increasing drag and in some circumstances causing lift.
Another important job performed by the tip plates is to create what is known as sideforce. This is the force which acts towards the inside of the race track. To create sideforce the left tip plate is positioned higher above the wing than the right tip plate, this is to allow the high pressure air on top of the wing to push more on the left side of the wing. The right tip plate is positioned lower below the wing than the left tip plate, causing the low pressure area pull to increase on the right tip plate.

Wickerbills
A Wickerbill or Gurney Flap is a small strip of metal added to the trailing edge of a wing. The theory behind a wickerbill is that it actually creates a small low pressure area behind the flap which speeds up the flow of air from under the wing, delaying separation and increasing downforce. Wickerbills of various sizes are used from around 1 inch to 3 inches. Caution should be used on high speed tracks as the use of a wickerbill will increase drag.
Rudders
Some wing manufacturers are now adding rudders to the underside of their Sprint Car wings. The rudders help to keep the air moving under the wing cleanly and to stop flow separation.
Mounting the Wing
Sprint Car wings are mounted high above the drivers head to ensure that the flow of air under the wing is not disturbed by the car’s bodywork. The top wing is usually mounted centrally over the car (sideways). Care should be taken when mounting the wing to ensure that the brackets are as aerodynamically efficient as possible. Anything that disturbs the air under the wing will affect the performance of the wing. Most modern Sprint Car wings have internal slides which keep the brackets out of the air flow. The brackets that support the wing at the rear are known as wing trees and the front mounts are called wing posts.
Hydraulic Wing Adjusters
Hydraulic wing adjusters allow the driver to adjust the position of the top wing while racing. The driver adjusts the wing using a valve called a wing slider which is connected to a hydraulic ram. The ram allows forwards and backwards movement of the wing. The hydraulic wing adjuster uses hydraulic pressure from the power steering system of the car, this is why you will sometimes see a driver turning the steering wheel left to right when testing operation of the wing slider. Some sanctioning bodies have banned these devices to keep expenses down.
Front Wings
As mentioned earlier Front Wings or Nose Wings are used to keep the front of the car balanced. Without a front wing Sprint Cars would be very light in the front end and hard to control. A typical front wing is six square feet and most rules stipulate that it must be mounted behind the front nerf bar and not be wider than the width of the front tires.
Wing Performance
There are a few important points to remember if you want your Sprint Car wings to perform as efficiently as possible. Ensure that surface of the wings are free from dents and holes, even things such as dome headed rivets can affect the air flow. Ensure any dirt is cleaned from the surface of the wings between races. As Sprint Car wings are subjected to extreme forces of up to 600 pounds it is imperative that all of the mounts and brackets are in good order. Many a great race has ended in tears after a wing has dropped or a tip plate has collapsed due to lack of support.
Setup
The wing can be used to alter a car’s handling characteristics. If a car is too tight or is understeering, the wing can be moved forward to increase the weight on the front of the car and decrease the weight on the rear. If a car is too loose or is oversteering the wing should be moved backwards to increase the weight on the rear.

 

one more thing
the faster we went the wetter the wing would become
even to the point of seeing a vapor trail with the naked eye

heres some other stuff i was looking at

As an object moves through a fluid, or as a fluid moves past an object, the molecules of the fluid near the object are disturbed and move around the object. Aerodynamic forces are generated between the fluid and the object. The magnitude of these forces depend on the shape of the object, the speed of the object, the mass of the fluid going by the object and on two other important properties of the fluid; the viscosity, or stickiness, and the compressibility, or springiness, of the fluid. To properly model these effects, aerospace engineers use similarity parameters which are ratios of these effects to other forces present in the problem. If two experiments have the same values for the similarity parameters, then the relative importance of the forces are being correctly modeled.

Aerodynamic forces depend in a complex way on the viscosity of the fluid. As the fluid moves past the object, the molecules right next to the surface stick to the surface. The molecules just above the surface are slowed down in their collisions with the molecules sticking to the surface. These molecules in turn slow down the flow just above them. The farther one moves away from the surface, the fewer the collisions affected by the object surface. This creates a thin layer of fluid near the surface in which the velocity changes from zero at the surface to the free stream value away from the surface. Engineers call this layer the boundary layer because it occurs on the boundary of the fluid.

The details of the flow within the boundary layer are very important for many problems in aerodynamics, including wing stall, the skin friction drag on an object, and the heat transfer that occurs in high speed flight. Unfortunately, the physical and mathematical details of boundary layer theory are beyond the scope of this beginner's guide and are usually studied in late undergraduate or graduate school in college. We will only present some of the effects of the boundary layer at this time.

On the slide we show the streamwise velocity variation from free stream to the surface. In reality, the effects are three dimensional. From the conservation of mass in three dimensions, a change in velocity in the streamwise direction causes a change in velocity in the other directions as well. There is a small component of velocity perpendicular to the surface which displaces or moves the flow above it. One can define the thickness of the boundary layer to be the amount of this displacement. The displacement thickness depends on the Reynolds number which is the ratio of inertial (resistant to change or motion) forces to viscous (heavy and gluey) forces and is given by the equation : Reynolds number (Re) equals velocity (V) times density (r) times a characteristic length (l) divided by the viscosity coefficient (mu).

Re = V * r * l / mu

Boundary layers may be either laminar (layered), or turbulent (disordered) depending on the value of the Reynolds number. For lower Reynolds numbers, the boundary layer is laminar and the streamwise velocity changes uniformly as one moves away from the wall, as shown on the left side of the figure. For higher Reynolds numbers, the boundary layer is turbulent and the streamwise velocity is characterized by unsteady (changing with time) swirling flows inside the boundary layer. The external flow reacts to the edge of the boundary layer just as it would to the physical surface of an object. So the boundary layer gives any object an "effective" shape which is usually slightly different from the physical shape. To make things more confusing, the boundary layer may lift off or "separate" from the body and create an effective shape much different from the physical shape. This happens because the flow in the boundary has very low energy (relative to the free stream) and is more easily driven by changes in pressure. Flow separation is the reason for wing stall at high angle of attack. The effects of the boundary layer on lift are contained in the lift coefficient and the effects on drag are contained in the drag coefficient.

HISTORICAL NOTE: The theory which describes boundary layer effects was first presented by Ludwig Prandtl in the early 1900's. The general fluids equations had been known for many years, but solutions to the equations did not properly describe observed flow effects (like wing stalls). Prandtl was the first to realize that the relative magnitude of the inertial and viscous forces changed from a layer very near the surface to a region far from the surface. He first proposed the interactively coupled, two layer solution which properly models many flow problems.

 

the more i have dug into this subject the more i find it all has already been done before

Popular Science (March 1933)

"Sea Gull Boat Skims Water At 70 Miles An hour"

Skimming the surface like a gull, a speedboat that rises clear out of the water has just completed its first trial runs successfully at Marshfield, OR. It resembles a hybrid between an airplane and a watercraft. Plywood-covered fins, shaped like airplane wings, extend from the sides in three successively smaller steps. By lifting the boat into the air, they virtually eliminate water friction on the hull and permit 70-mph speed without using unusual power.

Seated behind a small windshield in the one-man cockpit, the pilot operates a 55-hp motor of outboard type that dries the new boat. It behaves like an ordinary craft until it attains a speed of 45-mph. At this velocity, which corresponds to the takeoff speed of an airplane, an abrupt change occurs. The pilot can feel the boat rise from the water as the fins take hold on the air. Only the propeller beneath the hull remains I the water where its full thrust is effective. A small water rudder used a t low speed is now ineffective, and an air rudder, resembling an airplane tail fin, steers the boat. Most noticeable to an occupant is the absence of the bumping sensation experienced in fast watercraft. The cushion of air between the hull and the water acts as a shock absorber; the boat is literally riding on air.

Other advantages of the strange craft are pointed out by the inventor, Victor W. Strode, of Portland, OR., who has been granted a patent on the unconventional design. The boat turns in an abnormally short radius, with little tendency to tip. It possesses unusual stability largely because of the care with which the propeller was placed after a series of experiments --- about one-third of the way back from the bow of the boat to the stern. Complete streamlining minimizes air resistance and fuel consumption. While the hull weighs twice as much as one of the standard type, its extra weight is more than offset by the lift of the wings.

Since the first model is an experimental one, the inventor has made no attempt to provide seating accommodations for passengers. Its success in further trials may presage the building of similar, larger craft with enclosed passenger cabins. They would be suitable for use as pleasure craft, as mail or naval dispatch boats, or for high-speed passenger transport over inland water routs and might be used for express service for commuters.


IMO
there is just no way to point a finger and say eureka that's it

 

i used to live in key west and recall a surface effects craft being home built there, it was made of luan type wood and had a small air cooled eng. with air prop. i'm not sure if it was ever finished. reading this article reminded me of it and i wondered as you had said you lived there if it was you that built it.