New Jet Design

[steelcomp]

I think one of thte problems is that you can never 100% predict what the water will do. On pavement, you can look 100 yards in front of a car and know what to expect when you get there, but not in a boat. You can look 10 feet in front of a boat, and the water is still going to be different when you get there. Lot of blowovers were caused by the boat being forced into an attitude (by hitting bad water) that it wouldn't normally reach under a good run. That kind of occurance is almost instantaneous, and flaps, cannards, whatever, would have to react in miliseconds. Roof flaps on race cars work to keep the car from flying, but they still come off the ground and get very light, bounce around on the tires, and finally settle down. By the time all this happens on a boat, it's all over.
Just an observation...not trying to throw water on anything.

[maxwedge]

There is not enough altitude to regain control. If anything that unlimited had the best "controled" crash I'd seen but I emagine the driver was a few inches shorter after being piledrived into the lake.
I think best unlimited controlled crash has to go to Miss Beacon Plumbing last year in Evansville IN. See the video
http://www.youtube.com/watch?v=c65F3Bvn2y8
I believe all the modern unlimited hydros have canards (Fancy name for a front wing) controlled by a pedal, but it can only do so much. They were interviewing Miss Madison driver Steve David in Madison a couple years ago between heats on the podium and he said something like "I think a lot of people don't realize how much we use that pedal...and how little it actually does."
Flat bottom drag racer and last years Ahern Rentals unlimited driver David Bryant posts here on Hot Boat. Wonder if he could add some input. He posts under Davey B.
Nasa has done tons of reasearch on using computer operated flaps and spoilers to control airflow. I think a lot of it could be probably be applied to fast boats that hasn't been. A lot of it is public knowledge and even common knowledge among aeronautical engineering students and pilot types. Wind tunnel testing is expensive and pretty much way out of budget for most boat designers, but I've always wondered if maybe wouldn't be a bad idea to work on trying to get a research grant for a race boat related saftey project through an aeronautical university like Embry Riddle in Tucson or someplace like that.:idea:

[H20MOFO]

And he sticks the landing! Un-fricken -beliveable!

[Wizard612]

Great stuff guys. Here's an oldies story for you. We were racing APBA Kilo's and 5mi closed course attempts at bluewater probably about 1972-3 During one heat of I think Comp Jet, on the back straight ,some guy in a Horizon Jette did a 360 loop sim to the unlimited but this guy didn't loose a position and continued to race.

[Wizard612]

Steelcomp - Your comment on water conditions is the root of the problem. If you are taveling at 150mph and a roller hits the bow, that bow will want to rise making the boat ever closer to it's critical angle of attach or blow over angle. What can be done in that fraction of a second that allows the boat to not go bow up into that blow over attitude? 1) lower the bow 2) raise the stern, 3) lower the speed, any or all may be nessisary. How do you keep that bow from hitting that roller is an other possibiliy this could be done by 1) raising the boat above the water to prevent the bow from hitting the roller, 2) have the course officials not run a heat when rollers are present, 3) Design a track that reduces the risk of rollers developing ( Firebird was originally designed for that) 4) Submarine races!!!

[Cs19]

Nasa has done tons of reasearch on using computer operated flaps and spoilers to control airflow. I think a lot of it could be probably be applied to fast boats that hasn't been. A lot of it is public knowledge and even common knowledge among aeronautical engineering students and pilot types. Wind tunnel testing is expensive and pretty much way out of budget for most boat designers, but I've always wondered if maybe wouldn't be a bad idea to work on trying to get a research grant for a race boat related saftey project through an aeronautical university like Embry Riddle in Tucson or someplace like that.:idea:
I would love to take a daytona to a wind tunnel to have some experts take a look at it. I think there is something to the shape of the top deck of the daytona that creates lift. Its shaped like the top of a wing in between the pickleforks and I wonder how much lift is generated by that shape at 100? 135? Not sure if a wind tunnell would tell you that or not but i think that shape creates problems for the faster daytonas. Cheyennes dont have that shape and dont seem to have the problems eliminators have and are able to run positive nozzle angle unlike most daytonas. dont mean to hijack the thread, its kinda related...I hope

[sleekcrafter]

In this clip you can see the effects of the chop, on the hull, resulting in flight. http://www.youtube.com/watch?v=OQKHv...eature=related
I think minimizing the surface contact would be key to absorbing ripples in the water

[steelcomp]

I would love to take a daytona to a wind tunnel to have some experts take a look at it. I think there is something to the shape of the top deck of the daytona that creates lift. Its shaped like the top of a wing in between the pickleforks and I wonder how much lift is generated by that shape at 100? 135? Not sure if a wind tunnell would tell you that or not but i think that shape creates problems for the faster daytonas. Cheyennes dont have that shape and dont seem to have the problems eliminators have and are able to run positive nozzle angle unlike most daytonas. dont mean to hijack the thread, its kinda related...I hopeOn a true tunnel hull, that airfoil shape between the sponsons and center section
is very intentional and made to create lift. Your Daytona is a variation of that idea.
http://www.***boat.com/image_center/...ine-forces.gif

[BrendellaJet]

On a true tunnel hull, that airfoil shape between the sponsons and center section
is very intentional and made to create lift. Your Daytona is a variation of that idea.
http://www.***boat.com/image_center/...ine-forces.gif
I doubt they intended it to go as fast as some are though... The idea is to keep the boat in the water, not turn it into a wing capable real lift.

[TRG]

If it is an "Air Entrapment" hull, it is not too hard to figure out that the hull was intended to create lift as a wing does, look at the center of most all tunnels, the area between the sponsons start off lower than the area just one/two feet back, there is an element of downforce designed in all of the tunnels, the way i see it the wing that is used in the daytonas (19') are a big help with keeping them, not necessarily glued to the water, but definitly help with flying it too high, just a quick thought, i wonder if the wing, like the one used in the porsche, you know, the one that moves with speed (or however it works)?...would something like that help out in tunnell design? nevermind, im just dealing with diarreah of thought, and am having a hard time typing it out! lol
Todd