It was at LOTO this year and still has some BIG power in it. Don't think it is the original Brummett motors but it is not hurting on power and sounded great.

The only thing a cat would need to prevent a blowover would be a hydraulic spoiler on the deck of the boat, just behind the leading edge of the tunnel. It would deploy incrementally as the bow of the boat rises.

I know pretty much everyone on here has flown a commercial airline and seen those big flaps that raise up on the top of the wing. They are designed to kill lift. I linked a slow motion video:

https://en.wikipedia.org/wiki/Spoiler_(aeronautics)

https://www.youtube.com/watch?v=MOHG82Urj2Y

Hooked to some type of AHRS (Attitude and heading referencing system), this system would operate and react thousands of times faster than a human brain and body could react.

AND it was driven SOLO. For me, this is probably the most impressive LOTO Shootout run ever.

I will throw something else out there that kind of falls along the same situation we have with the speeds these cats and some v bottoms are now capable of. Not sure how many of you guys are snowmobilers but let me contribute this. Having been a snowmobile drag racer since the mid 80's, I have drag raced on every surface imaginable. Ice, grass, snow, and then the newest craze.....asphalt. Back in the late 90's when asphalt snowmobile drag racing was in it's infancy and sleds were lucky to dip into the 8's in the 1/4 mile, I started/promoted what was then the biggest/richest snowmobile asphalt drag race in the world here in Syracuse, NY. I did this for 5 or 6 years and the speeds and et's kept evolving at a rapid pace. Asphalt tracks were manufactured by one company, Camoplast, and still are. I know that back then Camoplast would not put a speed rating on their tracks and I was told verbally by the rep that they were never designed for speeds anywhere near 150 mph. Fast forward 10 years after I got out of it, and with the advent of 500-600 hp turbo powered sleds (I know because I had one for ice only), these things are running low 7's at almost 170 mph on the tar. I have lost one friend due to a top end crash on one of these on asphalt, and was familiar with another young man that was killed at the very same track where I had held my event for years. Bottom line is that in every form of motor sports, people are doing things that the originators of these vehicles never intended them to do. It's only when a fatality or two or three happen that we all take this huge step back and say, jesus, what the hell are we doing. People die climbing Mt. Everest every year. Why? Because if they succeed they are one of a select few people that can say they did. In the grand scheme of things, boat speed records, snowmobile speed and et records, and even a successful summit of Everest mean very little to anyone that isn't directly involved in that sport or hobby. Last I checked, no one wanted my autograph for putting on the biggest asphalt snowmobile race in the world, and outside of those who were there, no one even cared. Is a life worth all of that?

And therein lies the question. Where to draw that line?

Typically it's an individual's personal choice, but regulation comes into play when we collectively decide (or a governing body decides) to put ourselves in check. It's the balance of freedom vs common sense and it will always be subjective.

Its funny when you put it like that, I was all bent out of shape a couple years ago because I missed qualifying for the biggest short track race in the country by .004 Seconds. I was beside myself, then I thought about it for a minute and said why am I so upset over this, other than the 10k people here, nobody even knows this thing is happening right now. Even 95% of the population in Pensacola don't know this is even going on. But...when you're a racer at heart (or climber or athlete, etc.) it's not that easy to dismiss. A lot of people have that insane desire to go to the edge, and everybody has different reasons.

Amazed at all the reasonable ideas being brought up, and calm discussion this time around. Nice to see.

I do have to disagree with the just slow them down approach. We are still talking about speeds 100mph below the 317 record set by Ken Warby way back in 1978. Even the 244mph SoQ run is only on par with a 1957 boat record. Of course the big difference here is those craft were basically salt flat jets with sponsons glued on.. Verses the production prop boats with massive HP upgrades we have pushing the limits today.

Point is the bar was set pretty high a long time ago using a lot less technology than available today. Boats like Fight Club's do demonstrate the correct approach going forward. Center rudder stability for one, and a well thought out safety cage and canopy design as a back up. A couple more additions of modern technology, and things could be much different two or three years from now.

Below is a simple Photoshop modded concept submitted by a member over on boat design forum back in 2014 when some of us were discussing this same topic. Not that radical looking today is it?

[ATTACH=CONFIG]560663[/ATTACH]

Passion.

The reason we all boat in the first place. The reason we're all here on this forum.

Passion is essential to a full life and I think we'd all agree on this. It comes down to weighing risk vs reward in each situation, and it's different for every individual.

Yes to the rudder on the turbo skater, looks great.

A cat does not have an airfoil. It does not produce lift like an airplane wing airfoil. It relies on the forced air thru the tunnel which is compressed to create lift at the rear of the vessel, similar to an airplane experiencing ground effects, not airfoil lift. Once the attitude of the hull is great enough that the air it is encountering (plowing thru it, like a kite) exceeds the downward force of gravity, the hull behaves like a kite...Without a "string" to resist the force of the air, a blow-over occurs. At that point, disturbing the airflow over the hull or relieving some pressure has little or no effect on the result.

I get what you are saying. That is why I am saying that the spoiler would open gradually and most likely a tiny bit under normal operation, like when a big wave is hit and the bow comes up a couple of feet. The comuter would fully deploy the spoiler before the angle of attack was so great that the boat was to that kite point. Also, the spoilers on the aircraft are fully deployed as soon as the aircraft has WOW and are used to plant the aircraft to the runway, when it is in ground effect.

Think about how often somebody works their throttle hand in rough water, that is how i am saying this spoiler would operate, probably every couple of seconds in normal operation but would only fully deploy to prevent a blowover. A canard could basically do the same thing and also give you positive lift when needed, plus be programmed to get the boat at the perfect attitude every single time it is run, but at what point do these not become boats and more along the lines of a WIG.

I think Ron's decision is great and hope more follow. I don't think the shootout events will go away one way or the other. I am sure the manufacturers are discussing what has happened this past year and what if anything could have prevented the accidents.Whether changes are made or not there is always the chance of an accident in the boating world. RIP to those we have lost.

That's why a large portion of the tunnel roof needs to pop up in front of the windshield. Hinged up at the front of the boat.

A spoiler or flap cannot offset the tremendous wind force under the boat once it starts to lift. Maybe a parachute would work but it would need to deploy very fast.

Would anyone familiar with aerodynamics care to comment on this?

OK, Try to throw an arrow, feather side first. What happens? It will quickly switch to the point (heavy end) first. A boat, cat especially has, as does an arrow, a very high rear polar moment of inertia. Once the bow is up, even with a large hole in the tunnel, it is going to swap ends quickly. Also note that as the bow heads skyward, the effect of gravity holding it down diminishes by the square of the angle to level of the hull. Once all this starts, there is not much one can do to stop it without moving mass to the front very quickly (faster than can be accomplished realistically) or throw an anchor off the back (parachute) to counteract the physics involved in the dynamic sequence of events in a blow over. Question is... what triggers the chute and at what time???

Copelands Phenomenon was fitted with a frontal wing...wasn't that built/designed by a military aero guy/group

http://www.copelandsphenomenon.com/pheno1.htm

All it would have to do is prevent reaching the extreme angle of attack of the whole boat.

And at this point in time one's azz ends up in the drink. Having been in this spot myself, the speed at which one enters the drink has all to do with whether one comes out or not.

I have all the sympathy one can have for those involved here, their loved ones as well. The simple fact is that chit happens. simple as that, Chit happens!

To answer that question you have two obvious choices. Human interaction, by button or lanyard and seat of the pants input. Or human armed and computer activated system. Lets face it, a computer can calculate the angle of attack changes and estimate where the bow will be in next 30ms based off gyroscopic forces and speed quicker than you or I could ever hope by feel. However for a computer to make an accurate calculation, it needs baseline data to base that math off of. Which currently we have zero.

https://youtu.be/LDHx7_LTwWA

I wrote the app, and built some test rigs to start collecting data two years ago yesterday actually. Hardware cost about $100 a unit or less. Cellular based it even streams data live back to whomever you wish. When offered for free to all SBI teams in exchange for the data, it was shot down in flames... Without the data to build a working deployment model, human input is the only other option.

When in middle school I was a crew member on a 7 Litre Hydro Team. (I washed the boat and held it in the water waiting for the 5 minute gun) - anyway this boat had a system in where it would fill the sponsons with water should the front get light. So it would work like this...coming out of the turn, the driver would get on the gas, and start letting water out. If the boat felt good, he would continue to let more water out to "fly the hull" they called it all the way to the turn, at which time he would fill them back up so it would settle down really quick, could drive deeper into the turn, and could turn fast without rolling over. If going down the straight the driver felt the front getting light and rising too much, he would open the inlet, and it would fill the sponson up almost instantly. During the few years I was doing this I saw at least 12-15 boats go over, ours never did, and it held the lap speed record for whatever the course length was I don't remember.

Of course I realize a big difference between a 22 foot boat weighing almost nothing running about 145 MPH, and a 40+ foot boat running 175+, but a way to control weight in the front very quickly is perhaps something to think about?

What was their reason? Why cant you sign a NDA not to divulge to other teams and used for safety only. Its for their benefit.... WTF?

Technology havs been proven by Cirrus customers many times now. Watch video just below "Parachute maker BRS says 324 lives have been saved to date in successful full-airframe parachute deployments."
http://www.flyingmag.com/another-cir...aught-on-video

While there is no need or time to deploy such large canopy as used by Cirrus, a similar approach using a smaller drag chute deployed by an airbag inflation technique would be quickest. We estimated trigger to fully open chute in under 250ms at speeds over 100mph. When teamed with a computer controlled trigger, you'd be slowing down before you ever felt you were going up...

You built an AHARS unit it looks like.. I built one using a RY835AI 10Hz USB GPS Glonass BeiDou antenna module pressure Compass Gyro sensors and a raspberry pi

Actually Rik, that's a Samsung S3 mini stuffed inside a pelican case... :D

Samsung uses the best 9-axis MEMS chips on the market. So after exploring all off the shelf and breadboard options, it became clear that an Android app written for a $100 used cell phone would be just as accurate and more reliable than building something from scratch. That app along with several others now are available on Android for free. I have the PC side software also for anyone who wants it.

But yes your certainly on the same page. Data data data..

Sorry this is getting this thread off course, but I built a "Stratux" is why I used that Chip.. Problem is the system cannot read the AHARS so it was kinda useless feature so I bought a VK172. Both are WAAS enabled

No disrespect to all these ideas and concepts, anything to help make high speed boating safer is welcome to most, but think of what you are trying to do here.

To make one of these boats safer would be like taking a 57' Chevy and putting enough HP in it to compete with Top Fuel dragsters. You may get the speed, but the car design is antiquated beyond modification to be safe and stay together. And this is where the boat builders are in 2016. There is no real functional design technology in any of these boats. The only way to make them safer, is to go longer, and that still isn't a guarantee as we know from the Outerlimits blowover!

With these speeds, the responsible thing for a manufacturer who would like to compete in this superfast category would be to "start from scratch" and engineer a design specific boat for around speed, technology and safety. That would require a tremendous amount of money, like 10's of million$$$$, a seriously steep learning curve and real world testing with the use of wind flow dynamics and tunnel data. Just so they can design all kinds of technology that hasn't been created and tested yet. Remember, in the offshore industry, it's only 1957.

Oh, and I would guess that we would end up with something more like a trimaran, not a cat.

I have not been on OSO for a long time but the carnage of late is hard to ignore.

Tunnel boats are absolutely wings in that they create aerodynamic lift via a pressure differential between the upper and lower surfaces of the tunnel. Whilst an aircraft in free flight derives 2/3 of its lift from the upper suction part of the wing, a wing in extreme ground effect is the reciprocal. The suction portion of the wing produces the same quantum of suction lift as in free flight but the pressure side of the wing (by virtue of its proximity to ground (water)), produces vastly more lift. When combined with the effective increase in aspect ratio , GE lift is very efficient and that’s why aerodynamicists have been chasing this Holy Grail for over a century.


HOWEVER these poor chaps in the Skater are just the latest victims of GE’s dark side - The change in Cm (pitching moment) and centre of aerodynamic pressure (CP) when the wing (tunnel) starts to rise from the water and/or increase its angle of attack (AOA). In extreme GE, the CP is roughly 40-50% of the chord (subject to AOA, aspect ratio, section etc). Due to their ‘dirty’ upper side (cockpits etc) and very low aspect ratios, tunnel boats derive very little of their operating aerodynamic lift from the suction side of the wing (which acts at roughly 25% MAC). This explains why a tunnel boat’s CP is closer to the centre of area (i.e. 50% MAC) when in GE. However once the bow starts to rise, the CP moves towards the freestream point of 25% MAC and the nose down pitching moment decreases. Most tunnel boats have their lcg at roughly 70% of the chord, so once the bow starts to rise the CP moves further and further away from the lcg, and we all know what happens next. This is exasperated by the fact that at higher AOA's the tunnel starts to create vortex lift (same as Concorde) by virtue of its low aspect ratio. Therefore instead of stalling (as a conventional aerofoil would at a high AOA), it keeps on lifting and then (as mentioned in a previous post) pure drag takes over. If you look at the video of this most recent tragedy, the angular velocity is shockingly high. It shows just how out of balance the boat is (at this velocity) once it loses the stabilising support of the surface. Tunnel boats are partial aircraft with no means of aerodynamic control and negative aerodynamic stability (lcg is not even close to the CP once a perturbation which causes a bow up pitching moment occurs).

For those that have not been enlightened by Mr. Szolack’s astute decision, fly at high velocities at your own considerable risk,

ND1

DUDE, ARE YOU SERIOUS?
I can tell you're smart, but please put this in layman's terms.

What! ................. you didn't understand that? ;-)

Hi Naut, long time.

Found this old picture which I think helps visualize your explanation?
[ATTACH=CONFIG]560682[/ATTACH]

Red dot is the CoG position, green rectangle is the CP in ground effect, magenta is where the CP can travel as the boat moves with 6 degrees of freedom.

P.S. Still blows me away too...

Hey someone did ask if anyone familiar with aerodynamics would comment....lol

I'm right with you nautdesign1, but I'm a pilot with an engineering and aerodynamics background ;)

I knew Jim melley when I was a kid. I grew up down the road from him. I haven seen him in years and it's very sad to me to see this happen. Jim was always a speed guy. Started in motocross... Funny thing is many many years ago before motocross flat track bikes got faster and faster until the out profoarmed the tire technology. People where getting hurt and worse. Things advanced and got better because of science and learning from failure . But to keep putting yourself in this ( roll the dice) actions of flying a ( plane) with no controls nothing will be safe. Every time I have seen the posts or people from fiore to Garth and Jim ......it's to much to soon. I feel horrible for ALL the family and friends along the way... Congrats to anyone who knows that they are fast enough. It's hard to come to turms with that natural human instinct to be better fast stronger.

I had to read the post a few times but I think he's saying this.....

Planes get 1/3 of their aerodynamic lift from under the wing and 2/3 from suction above the wing.
A tunnel hull boat however, gets most of it's lift from under due to the compressed air through the tunnel and the hard surface (water) below.
The point of maximum lift is somewhere around the cockpit when the boat is running nicely.
As the bow lifts slightly, the point of maximum lift moves forward.
When the bow lifts up more severely, the point of maximum lift moves further forward and leads to an inevitable blow-over.

He summarizes by saying the tunnel boat has no way to control where the lift is centered, unlike an airplane wing. The boat is like a fixed wing being pushed further without altering shape to allow for higher speed.


Sounds like it's not possible to overcome the 'ground effects' lift from underneath because a boat is always running close to the water.

Please let me know if I've misunderstood and I'll correct/delete.

RR

I remember a lot of the hydros had " open" backs to the sponsons. Sitting in the water they were full. Then when they plained off, they slowly drained. Good memories

Think about what these guys are doing. Its all starting to make sense with all this "lift" talk... Consider that a Cessna cruises at about 140 and tops out at 185!

and a small Cessna Skyhawk can take off at about 75 mph.......:eekdrop:

Great input and conversation from folks in the know. Very enlightening.

Agree with ^^^^.
Interesting and informative thread, some pretty 'clued-up' guys with lots of great info!

RR