Where do we Go From Here?

[Kevin Krogness]

This is the 40 version of the new Boss rigger design.

Marty Davis, you should like the rooster tail behind this boat.

I must say, I never thought that rc boats were this advanced and how much thought goes into them until I read this thread. Thanks guys for dreaming and puting these ideas into a real boat. My other thought,,, were do I get one???

 

[Jorgen Andersson]

Charles

That looks really good. Have you both the 21 and the 45 up and running?

Stabiltzer wings:

I was just out testing some wings and the semi symetrical design that we have talking about here on the forum gives me too much downforce, even set at 0 degrees angle of attack.

I then switched to a fully symetrical wing, but otherwise the same design.

It ran really well with this one, and the stability at the rear was clearly improved.

It was the same feeling from low speed to full speed.

This was set at 0 degrees.

Jorgen

 

[Mike Larson]

Interesting thread..... posing the question, that as the hull achieves greater speed, the lift will increase to blow off proportions in a normal engineered ( todays pinnacle hull).... having the wing at 0 may work for awhile, until the physics overcome inevitably?...

Leading to, and how to adjust the wing for more downforce as the speed increases to critical.... servo and hinge?... helicopter gyro?..... weight issues with more components....... Lafluer's tunnels adjust trim on the fly.... and it works..... IDK, but, the top fuel dragsters still kite once in awhile, with a set wing.... it's there, surely, but, to what point, again?...( kite)..

keep it going..... mike

 

[Ron Olson]

Just to throw almost another equation into the mix, what about the water itself? I remember years ago about a discussion on if the water has a lot of sand, calcium or lime in it that can make the prop bite better.

 

[Martin Hamilton]

Ron i can remember many years ago we use to run on salt water and when we went to run on fresh water lakes the motors sounded like they were reving higher almost to the point of being slightly under proped Regards Martin.

 

[Hydro Junkie]

This is very true, salt water is considerably more dense than fresh. I've heard stories of people swimming in both the Great Salt Lake and the Dead Sea not being able to go under water because they were too bouyant in the extremely dense water

 

[Speed Jr.]

My full size boat runs about 4 mph faster in saltwater.........thats documented gps.

Jr.

 

[Charles Perdue]

This is the 40 version of the new Boss rigger design.

Marty Davis, you should like the rooster tail behind this boat.

I must say, I never thought that rc boats were this advanced and how much thought goes into them until I read this thread. Thanks guys for dreaming and puting these ideas into a real boat. My other thought,,, were do I get one???

Well, you start with an insatiable curiosity, a bucket of elbow grease, a love for model boats, ect......................

 

[anthony_marquart]

This is the best thread I've read in a long time,,..

thank you

 

[Tim_Duggan]

Stabilizer wings:

I was just out testing some wings and the semi symetrical design that we have talking about here on the forum gives me too much downforce, even set at 0 degrees angle of attack.

I then switched to a fully symetrical wing, but otherwise the same design.

It ran really well with this one, and the stability at the rear was clearly improved.

It was the same feeling from low speed to full speed.

This was set at 0 degrees.

Jorgen

Great post Jorgen,

Thank you for sharing your findings. Out of curiousity, do you think this approach would be useful for props that unhook in wakes etc. and did you need to change strut settings at all to take advantage?

Tim

 

[DON MAHER]

Great thread & very informitive!

I am no expert by any means,but I don't think that a wing used for heat racing would be very consistent. Wings on cars such as F-1 work very well because the surface of the race course is the same lap after lap. Just look at the water surface before a heat of 4 or 5 twins and then after a few laps. The point is the surface of water is never the same in heat racing. I do belive that a wing would be benifical for time trials, such as 2-lap & SAW because there is very little chop or wake with only 1 boat runing. As Martin H has said the wing works on tether boats.

Don

 

[Niklas Edlund]

Agreed, interesting thread.

My first Kep's rigger from 2005. The fin/stabilizer-set up was put aside though as it was my "comeback" season and we had to re-learn everything from back in the good old (80's) days. Its an area I/we will revisit for sure!

 

[Martin Hamilton]

Hi Tim what we find on our boats is though not recomended is some times a boat goes round and the motor wont come in and unload, Usual reasons not a good launch,prop slightly to big, to rich etc. By disturbing the water slightly (making small wave with your hand accross the surface of the water) when the boat is say half a lap away (50metres). When the boat goes through this wake its generally enough for the boat to jump and unload and away it goes with pipe coming in. The wing imediatelly stabalizes the boat after the initial jump,Some times they get a bit to excited doing this and end up making a wave or hole in the water and the boat leaps out the water to much even to the point of cutting the motor but the boat still lands flat on the water. Before we used these wings the slightest disturbance in the water would put a boat in so to speak. We can also run on rougher water as well without breaking boats as much,If the water is a bit to rough the boat normally just hops level. Before we used wings in these conditions we took boats home in pieces in a bag. Regards Martin.

 

[lohring]

We did a lot of testing on rear stabilizer wings on our 1/4 scale model of a proposed electric hydro design. The most interesting finding was how little the speed was effected, even with large deflections. Below is a picture.

When we were allowed to run lithium polymer rather than lead acid batteries, we went with a conventional hydro design. It is all ground effects wing and does a great job of getting everything out of the water at 100 mph.

Lohring Miller

 

[Jorgen Andersson]

Hello

Mike - Some time ago I did test with a stabilitzer that had a moveable elevator rudder mounted. The elevator was coupled to the radio and mixed with the water rudder.

On the straights it was adjusted as "neutral" and in the corners it had another setting.

This worked really well and made the boat run really light in the corners.

I will pick this thread up again later this summer.

Tim - When I did test the stabilitzers, the idea was to get a good boat even more stable and better hooked up all the time. It is working in that direction, but more fine tuning will be needed. When you get a rigger to run really light, the hook up of the prop will be an issue, hopefully this could help the situation.

Today I made some more stabiltzers with Divinycell as core and one layer CF on each side.

More tests to follow.

Don - If you get a wing working well on a rigger, I think it will improve the stability all the time, no matter if the water is good or bad.

All my comments have heatracing in mind, not SAW or time trails.

Please, we need some more "crazy" ideas to discuss!!!!

Thanks

Jorgen

 

[Charles Perdue]

To get any type of aerodynamic device to work its best with our boats, whether it is a verticle stabilizer, horizonal stabilizer or something other, first the airflow should be stable under, over and around the boat. This is done by reducing or eliminatining long flat areas, sharp corners on the upper side of the boat, rounding the nose and tapering the hull and sponsons so that the air will come back together with minimum amount of turblence, to fill the hole that the boat left in it while it was moving forward.

In our applications, we are pretty well stuck with the flat bottoms of the hull and sponsons so any changes will have to be done to the front, rear, sides and top of the boat.

I know that I am repeating myself on some of this. but until you control the air around the boat, the results will not be as consistent.

 

[TomMoorehouse]

More crazy ideas.....I've been thinking about a tubless rigger. Engine on one side rudder on the other.

 

[Jorgen Andersson]

Tom

Crazy - Maybe so, but please tell us more on your thoughts.

Jorgen

 

[Charles Perdue]

More crazy ideas.....I've been thinking about a tubless rigger. Engine on one side rudder on the other.

Tom, show us some sketches of your thoughts.

Talking different. Years ago, there was a guy testing a RC boat at Legg lake. He said that it was a scale model of a full size boat.

It used an outboard engine. The hull, looking at it from the top, was a hollow "U" shape with the bow of the "U" forward with the engine mounted near the front, inside of the "U" shape and it had planing surfaces like a shovel nose hydro underneath the front arc with small rear pads at the end of each rear boom.

He called it a "Skeeter" boat. It ran surprisingly well.

 

[lohring]

This is Mike Bontoft's 3.5 outboard hydro design. It raised the NAMBA SAW record over 20 mph to 81 mph.

Lohring Miller