Sponsons and Tub Tips

[Wasted wages]

I think it's been a learning curve for a long time,,
look at what guys did years ago on riggers..
As the speeds got faster, the boats began to lift off so much that they were putting flaps and wings on sponson booms to try to keep the boats planted.

Now that new technology has improved design and our understanding of what works best and the speeds are increasing to the point that current technology is becoming the limit, we need to look at every single critical issue to andvance further... which why I threw out the idea of the front boom becoming the leading edge of the sponson and tub.

Kind of like indy car tech, if there needs to be a part on the car, I guarantee that it is improved and incorporated into the design of the total car.
In other words,,we have to use a front boom to hold the sponson on the hull...why not incorporate it in every way possible.
That will lead to the rear boom attachment,, maybe that could be a triangulated tube design like that of the link bars of a RC truck or crawler.

This is just food for thought,,, I was thinking about how much air drag could be eliminated or directed around a rigger to advance the speeds and handling... that's all.

Watch this video and think about how stone age some of our boats seem...
This guy has major skills...

 

[Wasted wages]

Sharp sponsons work good. Tub not so much. The sponsons need to control the boat front end. The tub needs to be neutral on the front end. If you have to many surfaces trying to control the boat it never finds a balance be tween them. Sharp on the sponsons is good as you use the aero to control the front end. There is a top angle of attack on a sponsons. So the sharp front helps keep it on track. The tub does not need to control the front end. So rounded us better to keep it out of play. Just my 2 cents for what is worth.

This is the way I always understood it....
if so much time and effort is put into the shape of the sponson there must have been a reason.
Airflow and changes to AoA measured in thousands of an inch didn't just come around by accident...as well as adjustable rear booms.

 

[dwilfong]

You can get aluminum foils from K&S to put over the boom tubes. It is a waste of time just one more surface to manage in control the boat. The top of the sponson dose more than you think. The balance between the top aero and the bottom hydro is the trick. You have to build it in to the sponson from the get go. When you adjust one it changes the other. 3 on the bottom 0 on the top. Then adjust with shims form that.

 

[Charles Perdue]

Everyone has their own opinions.....

BUT, my dog in my avatar wants to chase Joels' cat that is in his avatar.
Lets get THEM racing......
David, your dog is much larger and is in another class and cannot race in ours. He may have to race in the twin class and chase two cats at the same time

 

[JRXHydros]

Everyone has their own opinions.....

BUT, my dog in my avatar wants to chase Joels' cat that is in his avatar.
Lets get THEM racing......
David, your dog is much larger and is in another class and cannot race in ours. He may have to race in the twin class and chase two cats at the same time

Cute little dog Charles,I have 5 pugs & my fastcat. Racing,well I would rather go & hangout at the pond & play toy boats with friends. I raced for years in boats & raced 1/10 scale off-road for years. When the transponder came out for car racing,then the rc car world grew into a mega star of fun,I know I was in it when it all started back in the 80s. Boats need the same thing,I want my lap time. My Opinion...

 

[Charles Perdue]

Joel, yes, Chaz is my BUDDY. I do not think that I could keep up with five like him.

Sometimes we get caught up in our personal opinions and take things much too serious.
I too really enjoy going to the lake, playing and hanging out with friends.
I have not ran boats for a while but after selling one of my businesses that was taking up way too much time, I am preparing to get back into it but on a limited level.

There are things that are serious but toy boats is not one of them.
Maybe we can meet at the lake some day and chat together......

Charles

 

[dwilfong]

I had to put my dog Skylar down last week.
Thy will have to wait to play with her on the other side of the rainbow bridge.
I gust started to build my own boat taking things from all the different boats I have run.
I find keeping it simple and incorporating the best attributes of different design has work out good so far.
No need to reinvent the wheel.
Thy say imitation is the best form of flattery.
That is where the inspiration for the Zegull came from.

Having to much fun at the ponds around me with this.
Toy boat will have to wait a little till I get tired of fishing.

O and crabbing .......LOL

 

[JRXHydros]

Sorry for hijacking your post Wasted Wages on Sponsons & Tub Tips.

 

[Wasted wages]

No problem...

That's a good looking bucket mouth and stone crab claw you got there Dwilfong!!
You must be from Fla ??

Sorry about your pup....had to do the same a few months ago myself... it's never easy..

 

[Charles Perdue]

Me too...I got a little side tracked.
Sorry about Davids dog....I would be lost without mine....he is one of the family around my house.

Charles

 

[K F Wheeler]

Some where there is a video that was made a few years ago. My cheese mind won't let me remember the guys name!
But it was a very well known designer and builder of the real unlimited hydroplanes that was talking about the leading edges of the real hydros.
As well as other parts of the boats. Interesting video!!! I've watched it twice and will do so again! It's on youtube.

 

[bermudadude]

really nothing new. it was discovered about 100 years ago. at least SHORTLY after i discovered model boats. facts- sharp leading edges make the boat "dart" ,with steering and water/air conditions. rigger/hydro/cat will dart up,down(submarine),left,right when u have good acceleration and/or at high top speed. u have to tell urself ur building a boat for its planned top speed not to go faster. if ur not a motor-head/speed demon the there are lots of problems u will never see and ur boat will be set up or designed completely different from the next guy.
food for thought

 

[KenOlvis]

Interesting read

Oval racing
Dose the weight of a boat get lighter
When the Hull hits a balance (riding on a cushion of air) today boats are so much lighter.
so fatten up the boat an turn right.
Finish the race you will place.

 

[LohringMiller]

I won a bet with Mike over sponson tube drag. He built an ingenious wind tunnel with a leaf blower that showed a streamlined boom had a lot less drag than a round tube. I said the difference wouldn't be measurable and got a free lunch. The streamlined section made a great flap to hold down the bow, though. We've done a lot of tests since. A distillation of this is in my articles on high speed boat design. The first is an introduction, the second is about airfoils, the third is about planing, and the fourth is about hydrofoils. See:

Propwash October 2016 Web.pub
Namba April 2017 Web.pub
NAMBA Propwash October 2017.pub
http://namba.com/content/library/propwash/2018/April/8/
Lohring Miller

 

[dwilfong]

A good balanced boat between aero and hydo forces will not get lighter. It will maintain its attitude no mater what the speed to a limit. I do not think weight will be a factor if the boat is set up with a good balance. Sharp on a sponsons keeps the aero on top of the surface. If the front surface is to be a set angle of attack I feel it needs to have a defined point . Now the tub on the other hand I feel needs to be neutral on the front end so a blunt end will help keep it that way.

 

[dwilfong]

Interesting read

Oval racing
Dose the weight of a boat get lighter
When the Hull hits a balance (riding on a cushion of air) today boats are so much lighter.
so fatten up the boat an turn right.
Finish the race you will place.

Kinda funny I put in for the race in Miami last weekend but could not make it. I still got a 3rd place trophy in X hydro. So the point is you do not even have to show up any more to place.....LOL
So a win is a win no mater what I will take my 3rd place with pride then...............................

 

[Charles Perdue]

There is some VERY good information online now, especially on some NASA sites, on air flow, ground effects and aerodynamics.

A little time invested in learning can pay huge dividends for you on understanding accurately how objects react at speed going through the air. Many ideas sound good until you apply some known scientific facts to them and then they are not what you may think...

Charles

 

[Wasted wages]

I like the old methods....reality.

Drive down the road 85-90 mph and stick a 2 ft piece of boom tube out of the window...

 

[Charles Perdue]

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[dwilfong]

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