350 Outrigger Hydro

[dwhitford]

My concern, Lee, is that without a bottom surface connecting the sponsons, what sort of "aero-tunnel" do you have to lift those sponsons from the surface on top-end straightaway? Won't the sponsons always drag and not lift free ... except maybe on bounces?


On the other hand, the concept looks quite stable, if fast enough down the chute.

[Guest]

Yes the sponson tips are legal. As far a construction, it does have a wood bottom and transom. The rest is Carbon Fiber and glass honeycomb panels. I didn't make the sponsons adjustable to save weight. The bracketry required is heavy. But I have provisions built in to the sponsons to change angles. If this design it close and shows some promise, I'll build rev 2 with some adjustability built in and lighter. Before I added hardware and windshield it weighed 105lbs. I've been told by several boat builders that it wouldn't work so I welcome any response. Positive or negative. I drew it up full size several years ago and after a failed attempt to buy a boat from Europe I decided it was time to try this.

Lee,
Years ago mid 70's I guess, Paul Keller in Michigan built a wooden Pro Hydro with aluminum sponsons, might have been a 350cc boat. The idea if I remember correctly, was to be able to change angle of attack and offset as required by the race course. I seen the boat run and at the time it seem to have some possibilities. Before I built my one and only capsule Hydro, I had the idea to built it with outrigger sponsons and rear running pads, but at the last moment went with a different design. I still have my early wooden model of the concept. What troubled me was to get enough strength in the tubes.
Good luck on your effort!
Bill

[Guest]

Lee,
I think Paul Keller idea for the sponsons, was to use a single large diameter tube so that the angle of attack could be adjusted easily up or down.

Comment - That right sponson outside edge seems a little too vertical for my liking. I would be careful the first few times around the course to see if it going to bite.
Bill

[bill van steenwyk]

Some time ago before Jim Apel moved to the NW I had him build a 125 boat of the 4 point design. Looked similar to Lee's boat, but of more standard type construction with the front sponsons attached directly to the cockpit sides instead of out side the main portion of the boat as Lee's design shows on a tubular bracket.

I would think the same way that Apel had the air traps on my boat would also work on this type design. On my boat the sponson ends ended just where they do on a conventional type, but then Jim put two pieces of aluminum approximately 1'8 to 3/16" thick from the sponson back vertical surface back to approximately where the non trips began as is shown in Lee's photos. Vertical slots were cut in the aluminum strips which were actually air traps and they were adjustable as to depth. This was done as this was the first 4 point he built for a 125 and he wanted a way to adjust for more or less air between the traps. I don't see any reason this could not be done with this type of design. other than the inside of the front sponsons would not serve any purpose as far as an air trap is concerned. The aluminum, strips could start right at the front of the boat and go back as far as desired. The air traps on mine went about 75/80 percent to the back of the boat and had a depth adjustment of about an inch at the back edge and could be adjusted so as to end up with a "taper" from front to back just like a regular designed boat with wooden traps that are also the inside edge of the sponsons.

In the 90's I believe, Apel built a 4 point 350 Hydro that Danny Kirts campaigned for several years, or maybe just one, don't remember now. It was built to be "adjustable" insofar as sponson angles and possibly even different sponsons could be tried. Jim explained to me that the boat was not built as an "adjustable" boat to be changed between race courses, etc., but was made adjustable so as to be able to change different configurations during the "testing" phase of the boat and then another one would be built incorporating the design features that were found to be beneficial, and then made permanent on the following boat that were found to be best. If Apel is still around in the NW perhaps he could lend some comments as to what worked and what did not. even though his 4 point design differs from Lee's boat in the way the front sponsons are attached and their location in reference to the main part of the boat.

As far as meeting the finer points of APBA rules such as rounded sponson tips, etc., I can very easily understand why those features might not be on the boat until the concept was proved and testing done. Don't think it would be required if you did not run the boat at an APBA sanctioned race, and if it were something that I built, I would not screw with the finer points until I determined it was going to either work, or not. Why go the extra trouble to meet rules like the sponson tip rule, when the boat is a prototype and the decision to run it in sanctioned competition probably would not be made until after it was tested. Plenty of time then to meet APBA requirements if wanted or needed.

[machinedcomp]

Good point Bill, my intentions weren't to race it in APBA anyway.

I had 2 of Jim Apel's 4 point hydro's A 350cc & 125cc. They had a wing section connecting the sponsons to the center hull.
So they relied on trapping air under the boat, and low pressure lift from behind the wing cord. My design relies on hydrodynamic lift rather than aerodynamic. At this point I'm not too concerned about turning it. Thats why I don't have a chine on the right sponson. The true test is making enough power to get the boat up on the riding surfaces. It's designed to ride on the inside rear corners of the front sponsons.

[blueskyracer]

These are really nice looking and great ideas.. Let us know how they work and what the issues are..

[Al Peffley]

I can't wait to see this boat run for the first time! Very cool to be able to look at his lofting drawings and view the hull's construction in person as it was being built by Lee in his Canby shop over the winter and spring. If you love to work on machines, advanced concepts design innovation with dissimilar composite materials is always fun, somewhat risky, and technically challenging all at the same time. If this first design doesn't work it can expire in a traditional Tietze Viking Torch Ceremony (like a prior, four-point hull I seem to remember after a rocket launch at Cullaby a few years ago - LOL!) For now, let's think positive and say it deserves to be thoroughly tested on a closed course and then "savored" if the power to mass ratio works as calculated by Lee for a PRO 350cc motor racing application. The innovations include some new control system ideas and a comfortable cockpit width design. As I said, VERY COOL. The black GrEp surfaces with the outrigger pods look something like futuristic vehicles produced by the Lockheed Skunk Works for Advanced Projects marine systems...

[Boatbum10]

Looks to me like the outriggers allow increased beam for greater stability, without increasing the aero lift to the point of a blowover, like extending the sponsons and decks of a traditional hydro would? I'm sure the sponson shapes could be used as aerofoils, and a partial side deck or wing on the rigger tubes could be added, kind of like the forward wing on the unlimiteds. The cockpit should create a little wing and ground effect lift, though how much I'd have a hard time guessing. With the kind of speeds your running I'd think it's not hard to get enough aero lift. Looks like there's a lot of freedom to adjust hydro surface locations and angles, which sounds like a stable and fast corner boat. Will be interesting to see how it does, and looks to me like regular trips out for testing

[epugh66]

Looks great Lee! Takes alot of effort to build a boat and give it a try. Good luck!

[mrlou40]

big smile on Lee's face on the FB page, I would say testing went well !!

[aaronhl]

Very cool- I've built my own rc version of a 4 point outrigger. I am interested in knowing what planing and dihedral/anhedral angles you you on front an rear sponsons? Was it designed to have the sponson tops to be parallel to water line? Have you made the bottom of the tub to taper upwards towards the rear? I can't wait to see the video of this

[machinedcomp]

Initial testing went well, Raced it this past weekend at Eatonville Washington. A few more heats and I'll be competitive.

[blueskyracer]

That sucker looks awesome.. Good job Lee

[dcrummett]

OMG, most of the thousands of WWII aircraft flown successfully against the Axis and Japan would not be approved for safety today, which goes to prove one of my favorite modern proverbs: "A rich man has many worries, a starving man, but one."

[Yellowjacket]

~While creating all of the lift from hydrodynamic lift is desirable from a stability standpoint, this generally results in more drag because the viscosity of water is higher than air.

The trick is to create the aero lift efficiently. Aero lift created by stagnating air under a hull isn’t particularly efficient. That is because the stagnated frontal area (essentially the area of the inlet between the sponsons on a conventional hydro) creates a lot of aero drag. The drag being the stagnated pressure times the area between the sponsons.

Wings are more efficient and can provide lift with very low drag (lift to drag ratios are typically 20/1 for wings) but have the problem of reducing the stability when the wing is big enough to support the entire boat. Bottom line is that you don’t want a lot of wing area forward, because as the nose rises the wing will generate more and more lift and obviously that is unstable.

Still, there is nothing wrong with designing the support between the hull and the front sponsons as a lifting surface with a wing cross section. This would provide some lift and reduce the drag of the front hydrodynamic surfaces. You want to move the air through there efficiently, and not create a lot of drag.

As noted above, tubes and things hanging out in the airstream create a lot of drag. While lots of folks think of big flat forward facing surfaces as creating a lot of drag, aft facing vertical surfaces have separated flow and those are what creates a lot of drag at high speed. Minimizing the areas that have separated or stagnated flow is how you get big reductions in aero drag, and that needs to be a design consideration too.

Just a few things to think about.....

[PRO-MOTIONRACING]

In the old days they built race boats called Hydroplanes. They were kind of a flying saucer looking thing that used a combination of hydrodynamic/aerodynamic lift. These boats were very unstable and there were many spectacular crashes. Most of those early Hydros were of a three point design, although there was experimentation with four point and two wing designs, there was even a turbine powered reverse three point boat that met with a well documented ending.
Then in the early 21st century a well known driver from Oregon, borrowing from remote control boat racing world and going against all critics and convention successfully produced a 350cc out rigger boat thus ushering in what was to become the modern era of outboard boat racing.