WOF building and general tunnel theories...

[Mike Larson]

Hey guys... Frost has arrived, and has Marty and I discussing possible new developments in a better test platform for the coming year... feedback from past refinements/results in the JD 29/30 WOF tunnel boat build are welcome.

With Marty's standard platform as a constant, i'd like to pose a few questions to possibly further the R and D with a little more radical build this year...

What effect/result is gained from a deeper depth of the tunnel?.. ie: 7/8ths to 1 inch per se

What effect/result would be gained by moving the center of the center section airfoil ( currently center hull) to a more aft position?...

On that same tangent what result to a higher actual airfoil height versus lower?

Has anyone tested the theory, of creating a wedge shaped tunnel, wider aft, and it's effects? ( Toe in on a rigger sponson while minute is not unheard of)

The incorporation of steps in the sponsons of the race hulls currently out there, poses questions of what %/age the steps are located and why?.... granted you couldnt just have "built 'em in there"

I suppose we could, and I probably would, but, with the hull known to ride on approximately the rearward 30% on plane, common sense thinking being that foreward steps are allowing the hull to break free from the waters hold easier, and arrive on plane quicker?....

While refinement to a basic platform could be taken as "if it aint broke" attitude, questions abound, while my knowledge/testing is more in the novice stage, combined information to at least whittle down some of the X factors would be appreciated. The building of an actual one off, and alleviating a small percentage of headaches testing is the goal here..... we could build a half dozen easy.... it's the time involved proving/disproving proto type theory for the summer i'd like to help with this post, ie: "well that dont work!" Granted, innovation has it's setbacks, and a fast track to stardom i'm not seeking, just general ideas, and a furtherance of tunnel information for all.....

Lotta builders out there.... throw out your radicality.... lets hear it.... mike

 

[Jerry Wyss]

You want an Idea? Copy the Lynx running surface profile and you'll be good there atleast. Find that apex droop

in the sponson that allows some vertical movement (in the bow) for cornering. h34r:

 

[Mark Poole ModVP]

A deeper tunnel will result in more air being scooped under the boat which usually means more blowovers as speed is increased.

Airfoil height has to work hand in hand with where the lift point is within the foil. Higher (thicker) foil means you are punching a larger hole in the air.

I have also thought about the toe out sponsons. Just remember that if too much compression is lost in the tunnel the boat will probably not perfrom very well especially if the rear of the boat is being sucked down.

I like trying new things also. With that in mind, look at the difference between some of the current tunnel designs. This is evidence that there is no magic bullet hull design. The key is to use proven principles in the boat design and then the rest is set up. I have seen proven tunnel boats run like crap in the hands of one person and then go like rockets and win races in the hands of another. Again, it is about set up.

 

[Body Guard]

Mark,

I've been doing tunnel R&D from 1989 till now and have found what work and what doesn't . I have a few designs which have been race proven and one may be produced in the US real soon but meant for OB gas.

Two types of tunnel theories are : tunnel scooping air under for lift. Most likely to blow over when speed increase. Tunnel scooping air under just for the purpose of working with the top deck air foil to create lift from the top will give you a flying tunnel when speed increase and can take off the water and fly level and land further forward safely to carry on running or racing if you are in the middle of one. Watch this happening on this link at 7.05 minutes.http://www.youtube.com/watch?v=Xl1PuHcVxsE.

Also other links for more of our race proven hull by now at least.http://www.youtube.com/watch?v=VuPZxIF4mVY

http://www.youtube.com/watch?v=ZMJ7xY9JVrE

My email bglatiff@yahoo

Latiff

 

[moparbarn]

want ideas? google switzer flying wing or switzercraft flying wing. not all results will show under either spelling, do both B) . a whole DIFFERENT take on tunnels.

 

[Body Guard]

Mike,

I agree with you, set up is the last telling touch on a race craft and that includes prop choice for the kind of waters you are running in. However, a hull design comes first and that is what you would like to be submitted here, right ?

I have raced with one of my design which proves to be user friendly in one of our many races here. It gave me such confidence in the race that it even rubbed off on the motors. It.s only a few of the many races that I didn't have motor problem. I even had time to fuel up the craft and chat with the others in between heats.Led from start to finish in the finals was something I don't normally do, as my preference was to start from behind to avoid first turn pin clashes.

Thanks moparbarn for the interesting link. It just help to confirm why wing configuration on a tunnel is much more important than the shape of the sponson

The thick wing on those crafts and the power they get from the old motors was right on the dot to give optimum lift while still keeping the gear case and prop in the water. Modern EFI motors will make that craft too 'flighty'.

Regards to both.