New Jet Design

[Wizard612]

I started a dicussion on a new design for a Jet Boat on the COMP JET IS BACK thread and it became an interesting diversion to the thread so I thought it would be better to have Comp Jet keep up that discussion and start a new one on this new idea.
I've worked up a new design for a Jet Tunnel that could be used for ether BFJ or even a Comp Jet or K jet circle boat and what to get input from you out there in Jet Boat Land. Background on this project can be found in the afore mentioned thread:idea:
http://www.youtube.com/watch?v=JPUcp3M9k0s

[cyclone]

I really like your design. can you explain some of the theory behind it, specifically the rear portion of the boat. It looks like the rear of the sponsons are stepped up and i'm wondering what the vertical extensions of the tunnels do.
thanks!

[sanger rat]

:idea:

[Wizard612]

The stern is sim to an eliminator but I've developed trap boxes to extend the air traps further back. The top of the traps act like aircraft elevators to increase or reduce the air preshure at the stern. The very back of the sponsons are extended to place the elevator controls inside the hull as well as the deck extention over the pump. Computer controled, they will deploy down when off plane to increase lift comming out of the whole, regulate the preshure as speed increases and help trim the boat in conjuction with the canard at the bow. As our software developes all this fuction should be automatic with the on board computer. I want the pilot to only worry about go & whoa in drag form. In sprint boat form I'm thinking a simple "set boat" button to automatically adjust the aero surfaces and nozzel to set the boat sim to plates on a flattie.:idea:

[Outlaw]

Beautiful, it nice to see a new look on things.
Are those tunnel extensions adjustable?
looks like you could actually fly it on the surface.

[sanger rat]

You are not going to need a droop on that thing.

[sstjet]

Looks good. I would think all of this extra material and hardware may add a lot of weight? The adjustable controls and elevators or flaps are probably not quite as important in a boat as they are in an airplane because, boats don't make the extreme manuevers that planes do. If it were possible to build this without adding alot of extra weight, then I believe that the idea does have good merit for boating. :)

[Wizard612]

I've always thought that a droop is a good thing to keep the thrust line as low as possible and limit the fulcrum angle between the intake and the nozzel as it relates to the direction of travel. Kind of like a lever at the transom pushing forward from the top of the boat at full throttle then releasing that preshure when throttleing down might well change the angle of attack and cauce handling problems.

[sanger rat]

You want something like this. http://www.hotboatpics.com/pics/data/500/8269gbMdzbkg8VYN-SCe6SRFIR7bennPcnXT0300-med.jpg

[Wizard612]

Problems of weight are a concern and this is why the project will need real structural engineering to put strength where it is needed and not all over as boats were layed up in the past. This will need to be Carbon fiber with selected Kevlar honeycomb, Epoxy/vacume bagged/ autoclaved technology and controls will be designed with fly-by-wire to keep it light. No 2x8 stringers and plywood bulkheads in this rig. I'm also concerned about the weight of the capsule. Current thinking is to make it sim to the unlimiteds that allow for a bottom hatch in lue of the capsule sepparating from the hull. In case of catistrophic failure the boat should leave the capsule not vise-a-vera.

[Wizard612]

sstjet - your comment about exteme manuvers in an airplane vs not-so-much in boats. I don't know about you but I can't think of a more extreme manuver than a drag boat out of control at 200 MPH. That kills a lot of drivers when G limits exceed about 20. Only the most extreme aircraft exert more than 3G manuvers in flight with military types doing about 9G before the pilot passes out. If I can design a boat that with aero controls that keeps those G's within survivable limits, even in a crash, then 90% of the design is a success.:idea:

[maxwedge]

That's a sharp looking boat!

[Placecraft Dragstar]

Boat is bad ass and so is the design! It is about time somebody works on something new.
What state are you in wizard612 ?

[Wizard612]

Wizard612 is SoCal, Orange County

[jetboatperformance]

VERY COOL !!!! lets see more Tom:D

[Wizard612]

I've posted some single images on the "comp jet's back" thread others can be created from the computer model but to be honest I don't want to show a lot of detail for a bunch of reasons, mostly legal ones. Someone try to make this thing and kills someone they might blame me so let me say now there is not enough design or resurch to make this thing safe or competitive so don't copy it!!!

[Sleeper CP]

Does it use an intake duct ? ;)
Sleeper CP
Big Inch Ford Lover:D

[Wizard612]

If what I think you mean by an intake duct as a completely submerged duct under the keel rather than the traditional intake mounted to the keel it has the later. I don't know how you could engineer a duct type that would have enough reduction of drag at high speed let alone overload the thing after a certain speed. The traditional ramp type intake has the possibility to load it even when it is above the water line at speed reducing drag greatly. Back in the 70s we thought of how to design an intake that reduced down the entry area as speed increased (like the SR-71s intakes) but the engineering problems seemed too great at the time. To revisit those ideas now would be interesting

[Sleeper CP]

I'm sorry I was being a smart ass :) The ;) maybe should have been a :rolleyes: . I'm sure some got a laugh out of it. I'm not going to bump it but on page 2 or 3 there is a very long thread about an Intake Duct. I hope it works out for them and they can figure out what type of boat it is good for.
Nice design though have any idea how far out you are on making one, but I probably just needs $$$ like so many new projects.
Sleeper CP
Big Inch Ford Lover:D

[bp]

The adjustable controls and elevators or flaps are probably not quite as important in a boat as they are in an airplane because, boats don't make the extreme manuevers that planes do. If it were possible to build this without adding alot of extra weight, then I believe that the idea does have good merit for boating. :)
if someone had watched several daytona/cheyenne blowovers, they wouldn't be thinking like that. trying to run those things on the edge is all about managing air pressures, and the way they've been, once they start to go, it's all over because there's nothing to bleed or manage the forces applied by the air.
i'd prefer to see an sfi cert'd capsule that seperates from the boat for several reasons. in cf, they can be light enough to not cause significant weight issues, but most importantly, they routinely save people. most recently, dale comes to mind, and also the texas boat in marble falls; both were going in excess of 220, and altough some injuries occurred, both drivers are alive. those are just the most recent - there are a lot of examples where breakaway capsules saved lives. john haas last year, rex a few years back at red bluff.. (i'm only mentioning the boats that were over 200 at the time they disentigrated). can't say that for those thunderboat deals. but it depends on what you're after - a dragboat in a sanctioned event, or something else..
also, you'd never know if a droop, short droop, or something else would be necessary until it's built and and can be tested.

[Wizard612]

BP- I can't agree more. I think I didn't explain my thoughts about capsules correctly. Capsules today are fitted into a complete hull and mounted in such a way that they break out of the hull when things are comming apart. I'm thinking that this capsule would still break away from the rest of the boat but when installed it completes the hull. If you remember the F-111 it had a crew ejection system that was the whole nose of the aircraft. Same idea here. The concept of the trap door like in the unlimiteds would be for escape in a roll over not violent enough to distroy the boat but trapping the driver in an inverted hull. Due to the CG moving forward in this design a roll over would not result in a bow up boat like we're all use to seeing but a flat bottom up attitude.
I also agree on the droop issue just drew it that way in the computer model to finish off the pump in the way I was familiar.

[lilrick]

By far the most interesting jet talk in the history of HB.:D

[sstjet]

I do agree with a lot of these points. The capsule is a great idea for safety and if you run a tunnel on the ragged edge you should have a capsule. I was just stating that the added weight may not out weigh the benefit. I do disagree in the manuerverability issue however. A plane turns in every possible direction, a boat does not. I don't include crashing as a manuever. It is the result of an manuever. The ideas are good ideas and are in use on planes for a reason, however some of these planes travel in excess of
1000mph. I think it would be cool if it could be applied without adding a lot of extra weight though, because it could eliminate a large portion of crashes. What about added cost?

[Wizard612]

Stability of any vehicale, plane, car or boat will greatly reduce the possibility of it getting into a catostrophic attitude. Jeff Bennet and I had sketches of a TFH back about 1980 that we hoped could be stable up to or through 300 MPH but no owner wanter to spend the kind of money needed to develop it. They would rather use it to develope HP in the engine. I have always wondered what if we did develope it how many lives it could have saved...
Ive tried to estimate the weight penalty of just the adjustible canard and stern elevators. Assuming most surfaces are carbon, electric acuators, wiring and computer controls these two items should not weigh more than 75lbs. A good diet and some excersise and I can loose that in nine months. The bulk of the extra weight in this design in in the beam width. Materials and methods can bring this final weight number pretty close to current weights. Future weighting once these materials and methods are used in a standard design would be another matter. But stability is the main issue. Lets think about F-1 cars where a driver looses control crashes into a concrete barrier @ 200+ and walks away is a much better senario than seeing the death of a friend on the 11:00 o'clock news. Costs: I know the development of this technology can't be cheep but I'm hopeful that by using off the shelf parts and a well thought out testing program, then amortizing those costs over 100 or so boats will fall in line with other motor sports. but who knows the idea of this thead is to talk it out, thanks for the input.:idea:

[bp]

wizard, i think that trying to create an environment that would provide the same safety as an f-1 is a noble idea, but it would have to be proven technology in a water crash to be considered safe, and realistic testing for that purpose could get real expensive, especially when trying to proven over a lot of years and losses that came with it.
if you look at today's capsule boats, the capsule is integrated with the rest of the skin. if you follow this link to randy krohn's site (hope i don't get in trouble with this) you can see that with glenn wilson's outrigger, the capsule appears to be integrated from an aerodynamic perspective. http://dragboats.com/gallery/picture_detail.php?PictureID=24485&RecID=14 this may not be exactly what you had in mind, but a cert'd capsule can be built that would work. i'm also more of a fan of hydraulic actuators instead of electronic, but that's just me... being water and all...
sts, i understand your thoughts regarding planes. my only point is that, currently and for at least 3-4 decades, once a blowover commences, there is absolutely nothing that can be done by the driver/boat/anyone, to stop it. if these surfaces can be operated to affect the air pressures in such a way that blowover conditions can be controlled, to call that significant is an understatement.
wizard, jeff talked to me about some of these concepts many years ago, when we were still working together on the biz. suffice to say, we went through some things that i (and i think jeff) don't ever want to again. this looks like a real good step in the right direction...

[sleekcrafter]

Today's technology of composites, certainly opens the door to advances in boat design. The movable surfaces, can be manufactured strong, yet light, and the mechanisms equally as light. These items would not need to be crash worthy, but merely safety devices incorporated in the new designs. Hull and capsule design would be main goals for survivability, in the event of a catastrophic event. Who would have thunk computors would take us this far, let alone make it happen. I hope to see you development of these ideas and designs in the future, it's amazing design work, keep at it.

[HOSS]

If what I think you mean by an intake duct as a completely submerged duct under the keel rather than the traditional intake mounted to the keel it has the later. I don't know how you could engineer a duct type that would have enough reduction of drag at high speed let alone overload the thing after a certain speed. The traditional ramp type intake has the possibility to load it even when it is above the water line at speed reducing drag greatly. Back in the 70s we thought of how to design an intake that reduced down the entry area as speed increased (like the SR-71s intakes) but the engineering problems seemed too great at the time. To revisit those ideas now would be interesting
Look into the Navy project with jets. I believe it was in the 70`s (late) at Textron down here. Drank a bunch of Bud so the brain cant remeber everything but really cool stuff.

[Wizard612]

bp- thanks for the input. The link to the photo is great. The interface between the deck and the capsule still looks to me like a complete separate capsule was put in the hull and the deck made to come up to it and match it at the edges. My thinking is close but differnt in one very different way. The bottom of the capsule is the bottom of the boat. I though, as I was looking at a capsule installation, that there was a redundant surface in that design. One capsule bottom and one boat bottom, both built quite strong and relatively heavy. The question then became how do I lighten the boat? answer, eliminate one of the two bottoms and let the capsule bottom take the load of the bottom of the boat.:idea:

[UBFJ #454]

My thinking is close but differnt in one very different way. The bottom of the capsule is the bottom of the boat. I though, as I was looking at a capsule installation, that there was a redundant surface in that design. One capsule bottom and one boat bottom, both built quite strong and relatively heavy. The question then became how do I lighten the boat? answer, eliminate one of the two bottoms and let the capsule bottom take the load of the bottom of the boat.
The way a SFI Certified Capsule has to be constructed (in particular, the way the Required Crash Cage Tubular Frame is constructed with its bottom cross bracing) and the way the rigid seat has to be attached to the frame excludes any bottom escape door. Additionally, any weight savings would be under 12 lbs., if modern composites were used.

[Jet Hydro]

i already have that boat with out all the lid and BS ;)
http://www.hotboatpics.com/pics/data/500/15497P1040404-med.JPG

[steelcomp]

This is great stuff. My thought on the cpomparison between an F1 driver surviving, and this design: The F1 car is designed to disintegrate, absorbing huge amounts of energy that would otherwise be transferred to the driver. To do that in a boat, you'd almost have to keep the "capsule" attached and allow the boat to do the same thing...come apart in pre-determined crash zones absorbing the impact and protecting the driver. A breakaway capsule escapes the dangers of the collision, but I imagine the driver can have one hulluva ride in one hitting the H2O at over 200. I guess the challange would be protecting the driver from the flying debris if he was to remain in the boat, but the F1 drivers are exposed as well. "Course, they won't sink and drown, either. I notice that the Aussies, in their open boats similar to our GN boats, (blown alky 130mph+) wear seatbelts and are sitting in race seats. Their boats are aluminum and don't disintegrate like fiberglass boats, so I wonder if it's safer to be strapped in one in the event of a crash, rather than get thrown.

[Xerophobic]

Their boats are aluminum and don't disintegrate like fiberglass boats, so I wonder if it's safer to be strapped in one in the event of a crash, rather than get thrown.
Better watch what you say or someone may misunderstand where you're coming from there! :D
LOL

[Pops@Aggressor]

Love what you have going- Would not a Gyro be required for computer reaction time on both the cunnard and the exhaust of the air entrapment release. I don't see the Driver reaction time being quick enough to save it.

[Wizard612]

POPS- we haven't even started thinking about how the aero could be controlled. small electronic lazer gyros are possible also preshure monitors at critical areas might work. Simuations will probably give us some good starting numbers including preshures above and below the hull which could be put into an angle of attach sensor and not rely on gyros.

[sstjet]

What about a pressure sensor similar to the stall warning on a plane? With it hooked to a computer that would sense too much pressure or lift and automatically adjust before a blow-over could occur.

[Wizard612]

Continuing... testing and simuations will obviusly need to be very extensive when developing this. We will be looking into sim. technology in other fields to see if we can develope off the shelf parts. Don't want to design an new widget for a gazillion dollars when a $5 part from a retired F-16 will do. Another way to answer your question POP, gyros may not be the only or best way to control it. Angle of attack between running fine and having a bad day may be so close together that the gyro system may not react fast enough ether. If that was the case maybe the gyro hooked to a "shit hold on" light may be required... I would hope that through the testing we will develope trends that the software could recognize through preshure, speed, angle of attack inputs and have the computer set the boat automatically to the best setting for given speed and water conditions. HEY THIS IS GETTING WAY TOOOO TECH... Right now it's just a drawing! Is is great to have fun with it though.:eek:

[steelcomp]

Better watch what you say or someone may misunderstand where you're coming from there! :D
LOL
It's not a rhetorical question. Refer to the F1 car that disintegrates on impact saving the driver from absorbing the energy. Your scenario is the exact opposite.
Remember the old Indy cars that when they flipped, they went bouncing down the track, not losing a single part? That was not good.
Not saying which is best or worse here, just saying there's a lot to think about on a clean sheet of paper.

[Wizard612]

That's one of the reasons I started this thread. I like to hear other opinions.

[Xerophobic]

It's not a rhetorical question. Refer to the F1 car that disintegrates on impact saving the driver from absorbing the energy. Your scenario is the exact opposite.
Remember the old Indy cars that when they flipped, they went bouncing down the track, not losing a single part? That was not good.
Not saying which is best or worse here, just saying there's a lot to think about on a clean sheet of paper.
Im just razzin ya! :D
Any links or places one can see these aluminum hull'd drag boats?
For the record I would rather be strapped into the hull with a rollcage and something that didn't break apart around me any day of the week vs being thrown our of something at those speeds
Cheers

[cyclone]

Continuing... testing and simuations will obviusly need to be very extensive when developing this. We will be looking into sim. technology in other fields to see if we can develope off the shelf parts. Don't want to design an new widget for a gazillion dollars when a $5 part from a retired F-16 will do. Another way to answer your question POP, gyros may not be the only or best way to control it. Angle of attack between running fine and having a bad day may be so close together that the gyro system may not react fast enough ether. If that was the case maybe the gyro hooked to a "shit hold on" light may be required... I would hope that through the testing we will develope trends that the software could recognize through preshure, speed, angle of attack inputs and have the computer set the boat automatically to the best setting for given speed and water conditions. HEY THIS IS GETTING WAY TOOOO TECH... Right now it's just a drawing! Is is great to have fun with it though.:eek:
Shoemaker once mentioned that some of the Daytona's with the wing on the front had a gyro controlling the angle of the wing. This was back when blow overs were more common. i think there's someone on this site that has one, although i cant remember his name or if he kept the gyro in place. You might want to contact Shoe and ask him how well it worked.

[Wizard612]

Greg's a great guy and lord knows he has experience in jets. But I think my old buddy Jeff Bennett had more to do with the adjustible wings on the daytonas from a technical perspective. I should give him a call...

[cyclone]

Greg's a great guy and lord knows he has experience in jets. But I think my old buddy Jeff Bennett had more to do with the adjustible wings on the daytonas from a technical perspective. I should give him a call...
sounds good. i figured i had some of that info screwed up. lol

[1968Droptop]

I like the drawing, and your ideas are outstanding. Disclamer, I by NO means can even come close to understanding air pressures on a hull like you've designed. One thing came to mind when I read this post and looked at your drawing. Is there anyway flaps could be designed into the front/middle top of the tunnel area. Could these not relieve some of the pressure that can cause a blow over ? Maybe the sponsons have to great of a surface area to overcome ?
I'll go back to drinking beer now............

[steelcomp]

I like the drawing, and your ideas are outstanding. Disclamer, I by NO means can even come close to understanding air pressures on a hull like you've designed. One thing came to mind when I read this post and looked at your drawing. Is there anyway flaps could be designed into the front/middle top of the tunnel area. Could these not relieve some of the pressure that can cause a blow over ? Maybe the sponsons have to great of a surface are to overcome ?
I'll go back to drinking beer now............ Something like a NASCAR roof flap. Good idea.

[1968Droptop]

Something like a NASCAR roof flap. Good idea.
That was EXACTLY what I was thinking ! Like I said, way outta my league here. But depending on how thick the top of the tunnel section is, it could be done.

[Warp Speed]

Remeber the anti-blowover design tried in Hydroplane racing?
I think it would have benefited from some of the modern air managment technology described in this thread.
I thought this was the coolest boat, and it did exactly what it was designed for. I don't think they thought about re-entry though. I remember watching it live and thinking damn, it worked!!............... Oh SH*T!!!!! :eek:
That guy was lucky!!!
http://www.youtube.com/watch?v=Hanb_nsjMjw
Damn rollers coming off the log boom will get you every time!!!
Warp Speed ;)

[Wizard612]

We called it a canard and It was a great idea poorly exicuted. I think they built one boat and when it blew up (but not over) they didn't stop to figure out why and the program ended. When a boat blows over it's angle of attack is so great it stalls just like an airplane. A boat is so short on wing span it will usually snap roll. The center of lift and the center of mass cause it to swap ends easily. The canard went airborn due to it's angle of attack but it's stall carateristics were much more docile due to the center of lift being much closer to the center of mass and the span being wider than a traditional design. Problem though when it fell out of it's stall it was 30 feet in the air and slaped the water like an egg on concrete. Even an airplane in a controlled stall will loose altitude before control is regained, hence the problems with boat design. You never ever want to get in that stalled angle of attack. 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.

[Wizard612]

I plugged in my headphones and listened to the audio on the link and heard that they weighted the nose to help keep the boat from blowing over. With what they were trying to do at first sounds like a good idea but as you can see the results in the crash caused the bow's now heavier mass to accelerate toward the lake faster after the stall recovery and the structure of the boat could not keep the now heavy bow from departing the hull, thus allowing the drivers legs to be browken when the bow left the boat... bad day!
The lesson learned is to keep the boat's attitude under control as the speed pickes up and the impact of the boat's angle of attack vs. the water conditions deteriorates. Opperable canards on the bow that would have kept the angle of attack flatter would have allowed that boat to keep accelerating until the prop came out of the water!

[Cs19]

I like the drawing, and your ideas are outstanding. Disclamer, I by NO means can even come close to understanding air pressures on a hull like you've designed. One thing came to mind when I read this post and looked at your drawing. Is there anyway flaps could be designed into the front/middle top of the tunnel area. Could these not relieve some of the pressure that can cause a blow over ?
great idea and we talk about doing something like that on the daytonas all the time, i just cant get myself to cut the holes. I feel it will work for a boat like mine but resale value is gone at that point. Its getting to the point on my deal that something has to be done, we'll see.

[Warp Speed]

Has anyone ever had a hull in a wind tunnel??
That may be interesting!!
Warp Speed ;)

[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=OQKHvihechE&feature=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/data/521/1729aeromarine-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/data/521/1729aeromarine-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

[Wizard612]

everyone on this thread are starting to get the idea of where we need to go from here. The wing section through the tunnels is intentional but I dought that that section has ever been analized with respect to ground effect, faster speeds, angle of attack etc. Though wind tunnel testing would be real interesting we have had years of test flights wih brave (or testosterone induced bravery) test pilots with pass after pass with no data aquisition. We are now starting to get that data but it needs to be put into a computer model to see what happens if... X,Y, or Z. without hurting someone. With the stuff we have talked about in his thread I think it's about time to build scematic model #3 and see what you all think. Issues I will try to address are weight & balance, Capsule design, Aero with controls, Sponson to tunnel angles hull strength etc.

[UBFJ #454]

Wizard612,
Just to keep things straight here, at least in my mind .....
From your posts I get the impression that the design your working with is for a Comp Jet, or, a Roundy Round Type Boat and not a Purely 'Point & Shoot' 1/4 Miler. Am I correct in my understanding?

[Pops@Aggressor]

Wizard612,
Just to keep things straight here, at least in my mind .....
From your posts I get the impression that the design your working with is for a Comp Jet, or, a Roundy Round Type Boat and not a Purely 'Point & Shoot' 1/4 Miler. Am I correct in my understanding? Im not sure also. If its a Drag Boat I think its going the wrong way.

[Goad]

yes, this thread started out as a comp jet concept over on the 'compjet is back' thread.

[Wizard612]

I think to do both with the same boat is not the idea but I think doing both with the same design with modifications is the idea I'm going for. The sketch on youtube more closely resembles the drag boat but as this thread continues the design in my head is changing a bit.

[UBFJ #454]

Thanks for the clarification.

[cyclone]

In this clip you can see the effects of the chop, on the hull, resulting in flight. http://www.youtube.com/watch?v=OQKHvihechE&feature=related
I think minimizing the surface contact would be key to absorbing ripples in the water
That video is scary to watch for a couple of different reasons. It basically shows that even with a tunnel that's running flat, a small hop across rough water is enough to push the bow up with enough positive angle to blow the boat over.
It tells me that even the guys who run their tunnels flat are susceptible to blowing over. not as much as the guys that like to fly the nose, but its a definate possibility.

[steelcomp]

That video is scary to watch for a couple of different reasons. It basically shows that even with a tunnel that's running flat, a small hop across rough water is enough to push the bow up with enough positive angle to blow the boat over.
It tells me that even the guys who run their tunnels flat are susceptible to blowing over. not as much as the guys that like to fly the nose, but its a definate possibility.The underside of the "airfoil" if you will, isn't in purely clean air when the boat's on the water. I think what happens isn't due soley to the increased angle of attack, but I think it's also about allowing more air under the boat and getting the airfoil up in clean air where it actually creates more lift than desired, and the boat begins to literally fly. Becuase of the weight and balance, and without the drag of the water to stabailze it, the natural tendancy for the airborne hull is to go nose-up, and fly over backwards. Even an airplane will do this. Here's an example...I used to fly gliders out at El Mirage, and it would get so windy that I could actually ground fly the glider. Sitting in the cockpit, I would pick up the tail, level the wings, and balance on the single landing wheel. Thing was, that if I didn't have the dive brakes open killing the lift on the wing, the plane would leave the ground, and instantly flop straight over on it's back. Not exactly sure why, but I bet the two behaviors are very related.

[bp]

That video is scary to watch for a couple of different reasons. It basically shows that even with a tunnel that's running flat, a small hop across rough water is enough to push the bow up with enough positive angle to blow the boat over. .
if that were true, every one of them would blow over at every race.
It tells me that even the guys who run their tunnels flat are susceptible to blowing over. not as much as the guys that like to fly the nose, but its a definate possibility.
anything -can- be susceptible to blowing over, but attitude is only one attribute, and not necessarily the most important. dynamic c/g, or balance, for the intended speed is the most important factor.
the boat in this video began to climb for no apparent reason which indicates to me that it was not set up properly, balance wise, for the intended speed. lift is good, climb is bad.
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.
the problem is that the dynamic c/g shifts further and further rearward the faster you go. this has to be accounted for as the boat goes faster and faster. at some point, options are limited other than adding weight or significantly modifying the area you're talking about, which wizard's design does do.
there is nothing wrong with lift - as long as no climbing occurs simultaneously. if the nose begins to climb, you are done as it turns into a sail.
in '01 at red bluff, we ran the fastest that boat ever went, 134.9, and the boat hit a small roller right at the end of the lights. the whole boat lifted, and settled right back in - no climb. the dynamic c/g was correct for the speed/power applied (and it looked bitchin too).
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.
i would say, ask joe barnes about that (rip 239), but you cannot. cheyenne's can blow over just as easily as daytona's can - they may be able to run safely at a designated speed with a little more [I]attitude[I] than a daytona, but it still boils down to having the correct dynamic c/g for a given speed/power applied. greater attitude doesn't necessarily equal quicker/faster; lift does.

[Wizard612]

bp- I'm confused, please give me your best definition of dynamic CG. to me the center of gravity (or more appropriatly the center of mass) is not a dynamic location unless something in the boat (ie. mass), is moving. CG does not shift with speed. lift changes with speed and the center of lift might well change with speed. Center of lift can also change with the angle of attack as it pertains to speed. but the mass of the boat as it pertains to the boat only stays put. ( well ok it is moving in the same direction of the boat but it is in the same XYZ coordinate within the boat).

[Wizard612]

Cyclone - reading your reaction to the You tube clip on the hydro crash I have problems with much of what you are concered about. I don't for a minute think we can stop all crashes but let us talk about what your concerns are. 1) Tunnel boats - that video was not of a tunnel boat but one of an unlimited hydro, if there is ever a class of boats that can't react quickly it's an unlimited hydro. the tubine takes forever to spool up and down just for starters. 2) smooth water - nope not there, that chop that may look to the casual observer as flat is probably 1' chop with occational 3' holes. I counted at least 8 instances where that boat was upset by water conditions on that one straight-a-way alone. 3) he was running flat - Unlimited hydros can't run any other way. the forward mounted sponsons the thrust angle of the prop shaft, the whole concept of Hydros as they were designed over 60 years ago demand that they run flat when they don't you REALY have a problem compared to jets. 4) I didn't calculate the angle but the boat definately entered an attitude, long before it flipped, that it had not entered before, that it could not get out of. 5) once the boat was commited to the crash the design did not allow for the even semi-controled departure and re-entry to the lake surface. The (what is currently) A-typical lift, snap-roll and re-entry, assured the MAD ( mutual assured distruction) of boat and sometimes the opperator. I have been thinking about these senarios and the nightmares they may produce for over thirty years and I strongly believe that by avioding the "some will blow over no matter what " mind set, we can run boats faster, straighter, handle better, includung getting arround turns harder, and most of all do this all safer than we ever had before. :argue:

[Hass828]

Cyclone - reading your reaction to the You tube clip on the hydro crash I have problems with much of what you are concered about. I don't for a minute think we can stop all crashes but let us talk about what your concerns are. 1) Tunnel boats - that video was not of a tunnel boat but one of an unlimited hydro, if there is ever a class of boats that can't react quickly it's an unlimited hydro. the tubine takes forever to spool up and down just for starters. 2) smooth water - nope not there, that chop that may look to the casual observer as flat is probably 1' chop with occational 3' holes. I counted at least 8 instances where that boat was upset by water conditions on that one straight-a-way alone. 3) he was running flat - Unlimited hydros can't run any other way. the forward mounted sponsons the thrust angle of the prop shaft, the whole concept of Hydros as they were designed over 60 years ago demand that they run flat when they don't you REALY have a problem compared to jets. 4) I didn't calculate the angle but the boat definately entered an attitude, long before it flipped, that it had not entered before, that it could not get out of. 5) once the boat was commited to the crash the design did not allow for the even semi-controled departure and re-entry to the lake surface. The (what is currently) A-typical lift, snap-roll and re-entry, assured the MAD ( mutual assured distruction) of boat and sometimes the opperator. I have been thinking about these senarios and the nightmares they may produce for over thirty years and I strongly believe that by avioding the "some will blow over no matter what " mind set, we can run boats faster, straighter, handle better, includung getting arround turns harder, and most of all do this all safer than we ever had before. :argue:
Great topic, great arguments that you guys are making. I like your ideas wizard keep thinking outside the box. This is were great inventions come from to help us all be faster and safer. Just be sure to share the wealth when you come up with somthin that you get the time to test out:D

[Wizard612]

Hass828 - If I can do something no dout in my mind I would share it. Just get out the old American Express and donate to the cause.

[Placecraft Dragstar]

Hass828 - If I can do something no dout in my mind I would share it. Just get out the old American Express and donate to the cause.
He should, looks like he has $$$$$ he has posted that he wants to buy some land and make a drag boat facility to run everyweekend.

[bp]

bp- I'm confused, please give me your best definition of dynamic CG. to me the center of gravity (or more appropriatly the center of mass) is not a dynamic location unless something in the boat (ie. mass), is moving. CG does not shift with speed. lift changes with speed and the center of lift might well change with speed. Center of lift can also change with the angle of attack as it pertains to speed. but the mass of the boat as it pertains to the boat only stays put. ( well ok it is moving in the same direction of the boat but it is in the same XYZ coordinate within the boat).
no, i don't think so.

[steelcomp]

no, i don't think so.
Huh? :idea: :idea:
Here's my thought on "dynamic" cg..if the boat's nose comes up, it moves on an axis, call it the pitch axis which will typically be rearward of the CG. If you have a vertical line through the pitch axis (referencing gravity) and a vertical line thourgh the CG, the pitch axis remains the same as the nose rises, but the vertical line through the CG moves rearward, getting closer to the vertical line through the pitch axis. Of course, the CG is also rising, and technically not moving rearward in relation to it's actual location in the hull, but in reference to the pitch axis, it does move rearward. As weight and balance is concerned, when the nose rises, the CG changes along with the basic shape of the hull. When flat, the hull is 18' long by say 24" high, and the CG may be 6' from the transom. As the nose of the boat comes up, the "dimensions" of the hull in relation to gravity change, and at the extreme, if the boat is vertical, it's dimensions are now 24" long by 18' tall, and the CG is now 6' off the water. Gravity is the key here, and the reference to it, not speed or wind resistance or aerodynamics.

[UBFJ #454]

Huh?
While bp is certainly able to explain if he chooses to, from my perspective it's kinda like our Crew Business Manager says: "If someone someone can't turn the computer on, what good is it to try and explain the Program?"
Having said that ...
CG is a Mathematical Concept used in design work to describe the Center of Mass of an object. The Static CG describes the Center of Mass at Rest. Some designers us the term 'Dynamic CG' to describe the CG in Motion.
In terms of Tunnel Boats in motion, when they are moving 3-dimensionally in WIG Effect (Wing In Ground Effect), the 3-dimensional Position of the CG (Relative to the Outside X,Y,Z World they are moving in) is Constantly Changing and very different than the Static, At Rest CG. This is why some choose to use the term 'Dynamic CG'.
True, in terms of the boat's own Reference Frame, the position of the Center of Mass doesn't change (disregarding sloshing of fluids) when it is in motion, but, not to understand that the CG is Dynamic (Constantly Changing due to the Aerodynamic & Hydrodynamic External Forces exerted on the boat) in its position when in the X, Y & Z'd World of Motion is .........
The 'Computer' is now 'Turned On' ... Do with it what you want.

[bp]

While bp is certainly able to explain if he chooses to, from my perspective it's kinda like our Crew Business Manager says: "If someone someone can't turn the computer on, what good is it to try and explain the Program?"
Having said that ...
CG is a Mathematical Concept used in design work to describe the Center of Mass of an object. The Static CG describes the Center of Mass at Rest. Some designers us the term 'Dynamic CG' to describe the CG in Motion.
In terms of Tunnel Boats in motion, when they are moving 3-dimensionally in WIG Effect (Wing In Ground Effect), the 3-dimensional Position of the CG (Relative to the Outside X,Y,Z World they are moving in) is Constantly Changing and very different than the Static, At Rest CG. This is why some choose to use the term 'Dynamic CG'.
True, in terms of the boat's own Reference Frame, the position of the Center of Mass doesn't change (disregarding sloshing of fluids) when it is in motion, but, not to understand that the CG is Dynamic (Constantly Changing due to the Aerodynamic & Hydrodynamic External Forces exerted on the boat) in its position when in the X, Y & Z'd World of Motion is .........
The 'Computer' is now 'Turned On' ... Do with it what you want.
very good. thanks.

[steelcomp]

While bp is certainly able to explain if he chooses to, from my perspective it's kinda like our Crew Business Manager says: "If someone someone can't turn the computer on, what good is it to try and explain the Program?"
Having said that ...
CG is a Mathematical Concept used in design work to describe the Center of Mass of an object. The Static CG describes the Center of Mass at Rest. Some designers us the term 'Dynamic CG' to describe the CG in Motion.
In terms of Tunnel Boats in motion, when they are moving 3-dimensionally in WIG Effect (Wing In Ground Effect), the 3-dimensional Position of the CG (Relative to the Outside X,Y,Z World they are moving in) is Constantly Changing and very different than the Static, At Rest CG. This is why some choose to use the term 'Dynamic CG'.
True, in terms of the boat's own Reference Frame, the position of the Center of Mass doesn't change (disregarding sloshing of fluids) when it is in motion, but, not to understand that the CG is Dynamic (Constantly Changing due to the Aerodynamic & Hydrodynamic External Forces exerted on the boat) in its position when in the X, Y & Z'd World of Motion is .........
The 'Computer' is now 'Turned On' ... Do with it what you want.Guess I should have used words like "mathematical concept" and WIG, or 3-dimensional, X,Y, and Z.:D
So finish your sentence, Jak...not to understand that the CG is Dynamic...is .........

[UBFJ #454]

Guess I should have used words like "mathematical concept" and WIG, or 3-dimensional, X,Y, and Z.:D
Scott - I wasn't critizing what you posted so don't go 'Beating That Dog' ... I posted in the way I did so people could go Research the 'Terms' and find out what they meant if they didn't already know.
So finish your sentence, Jak...
Naw ...... To quote bp ... "I don't think so".

[steelcomp]

Scott - I wasn't critizing what you posted so don't go 'Beating That Dog' ... I posted in the way I did so people could go Research the 'Terms' and find out what they meant if they didn't already know.
Naw ...... To quote bp ... "I don't think so". Would defeat the reason I posted it that way.
Sorry Jak...shoulda added :D :D to the end of my last post. Just funnin' ya.
AFA Bob's "I don't think so"...I think that was some what of a brush-off...if you don't want to answer, just don't answer.
This isn't adding anything to the thread, though. Sorry.

[bp]

AFA Bob's "I don't think so"...I think that was some what of a brush-off...if you don't want to answer, just don't answer.
This isn't adding anything to the thread, though. Sorry.
he asked a question, i answered with as much as i'm going to. if the peanut gallery doesn't like it, tough.

[Pops@Aggressor]

I think to do both with the same boat is not the idea but I think doing both with the same design with modifications is the idea I'm going for. The sketch on youtube more closely resembles the drag boat but as this thread continues the design in my head is changing a bit.Let me throw out my feelings.
#1 Fuel Boats will soon need to get away from Air entrapment design. The Cozy style of outriggers, no air entrapment will become the next safety feature in Fuel Boats. Motors are monster now, ETs are getting so quick you don't need aero dynamic lift as found in the tunnel.
Twin Prop TFH are now starting to run this and have proven that. I am aware of the Ron Jones Hydro lift that is being utilized by Props yet this will not fit the Pump format as it enterfears with the pump load process. see no reason why a smaller center pod with outriggers would not fit the bill. This beats the conard wing of control, which I see no way of that working in a TF pump with out a Gyro- to Computer, The Driver would never react to the time element. In Circle I would think that Art Carlsons Patent design would be the winner. Tunnels after center retaining the frontal V keel for turning and primary climb lift and a controlled aft tunnel effect. My 2 cents only.

[Wizard612]

OK guys I don't think I had too much wine for lunch but your discussions have thrown me a bit. For evaluating what goes on in a boat at speed you should not look at the outside world as affecting the boat except for lift, drag and dynamic forces i.e. air and water hitting the hull (which can also be described as lift and drag) the boat itself has mass and thrust going for it. Engineers always want to simplify to the simplest common denominator. This hole idea of dynamic CG does not fit within any equation I'm familiar with in the design of moving bodies through fluids (air and or water) unless you have some big old weight in the boat on rollers that move around, or water tanks that fill and drain like some ski boats, fuel burn might effect CG a bit depending on where the tanks are located. This type of discussion is what I heard thirty years ago on the beach at Long Beach. People described how they thought about an issue in words but when it came time to describe it in numbers it was ether way too complicated to reduce it to an equation or it just fell apart in confusion. Now if I'm as full of water as some lakes we used to run in, fine, but will someone will please tell me how your supposed a design a boat with a dynamic CG?:idea: