Hydroplane aerodynamics

[ram95]

You OPC guys go pretty fast. Anybody know of any material, books, technical or otherwise, etc, which talks about the aero-dynamics that come into play when running a few inches above the water at the speeds you run? I realize that tunnel-boats run powertrim. An advantage, as opposed to stock and mod outboard hydros where the engine thrust angle is fixed while underway.

Try to be kind huh.. the river is frozen 2 feet thick, the freaking fuel-oil tanks are about empty ( mission accomplished!!!) The $1400 plus bucks it would cost to fill them went for a new J motor for my kid. The warmest thing in the house is this PC and the heating pad under my feet. This is Maine.... as the sign at the border says: "Maine, the way life should be". Yeee haaaa!! So much for life in the slo lane up hee ahhh.

Got ice?

Alex
12A DSH

[sam]

THE book

http://www.aeromarineresearch.com/stbd2.html

[Silas_53A]

Maine's weather, don't like it wait 5 minutes. During a snow storm last week we couldn't see the road 40 feet in font of the shop, went back to work and didn't pay attention. 30 minutes later UPS showed up and I helped him with the packages, was blue skies with ZERO clouds! And there is 0 exaggeration in that story!

(Sorry for being off topic and being no help )

[crankbearing]

Books

Alex,

The first books you want to buy are from a PILOT's book store and the history of airplane wings (not too technical! Sorry.)These are not titles. Go to any pilot training center personal or professional (Not your local " hair care, tire center & airport") They will have a list, My buddy was in pilot school for a while and had left his books with me a few years back and I have read them front to back about three times and everytime I do I learn something New.

Subjects

Aeronautical Engineering
Aero/Hydro (dynaimcs)
Boeing has published some great reading, I had a story of the wing development on the 777 and the tasks they had to overcome which I cannot find for the life of me. the tech data in that report alone are amazing

When Dave Rawson (Canada) built his first Rawsoncraft he booked time in the Ottawa Wind Tunnel with that boat, I think he booked three or four hours of testing and the TECHS were so into the project that it ended up being in there for a couple days at no charge and the stuff he learned from that testing is amazing.

HERE is a big tip - Absolutely NO square edges make them all round.

A square edge is the biggest drag coeffient you will find, in the test with flow over the boat any square edge show the flow stopping and shooting straight up in the air stopping or hindering any current smooth flow over the boat or air frame if you want to call it that.

Regards,

Dave Scott

[Fast Jack]

wings

Dvae, Alex is a CFI. I bet he can tell ya why things fly .!!!!

[Blackhawkguy]

Square edges

I do believe that your comment on square edges is correct for any part of the boat that air goes over but the trailing edge of the bottom or chines needs to be a sharp, square edge, otherwise the water does not break clean away. Gary Romberg told me that there was a study done on Unlimiteds having to do with Aero and Hydro dynamics, you may check with the APBA headquarters on this and see if they have it. Boats are alot diferent because you not only have air but water to deal with.

Kerry

[sam]

EVERYTHING you'd even remotely be interested in - is in Jim Russell's book. He covers every part of both aerodymanics and hydrodynamics from the Wright brothers to Seebold

[Kelli Pomphrey]

Also, if you can contact Bob Wartinger, he could give you all the hydrodynamics you need to know.

This is screen name "MGallagher" by the way.

[ram95]

Geez guys! This has been great. I was expecting a real beating, but all your comments have been a lot of help. I've been thinking of buying Jim Russells book but wasn't sure if it was what I needed - I'll go buy one. And, I figured someone had put a hull in a wind tunnel, but had no idea who it was. Dave's right about flying books - I've got a pile of them and am fairly familiar with why wings work, that knowledge has kept me alive... along with an active elevator, rudder, and ailerons. But, it's the 'fixed' aspect of a hydroplane traveling thru the air with no controllable surfaces that has generated a lot of different opinions as to what affects what. It would be one thing if the speed of the air remained constant at top end (no wind gusts, no headwind, crosswind or tailwind). And, if there weren't that prop blade and bullet in the water. Flying an airplane real close to the ground, in what's referred to as 'ground effect' over a flat prairie is one thing. Trying to keep it over the center of a runway ( down the back straight ) is another matter. One needs aileron and rudder for that trick. And, at 60 to 80, in a light aircraft a 3 or 4 knot wind-gust will result in an increase in altitude. It's a function of the angle of attack. Walking around the pits looking at the various hull layouts, it's obvious there are different theories, most born from experience along the way. I really appreciate and want to thank you for all of your comments. This is a great website.
Alex