Model Boat Turning Dynamics

Marty Davis · Dec 24, 2011

I have wanted to write a Technical Paper about Turning Dynamics of Hydros for a long time and finally got a little time to complete the project. I have posted the new Technical Paper at http://rcboat.com/past.htm It will be the top article.

I think that a lot of the items in the paper will apply to almost any of our classes.

Comments welcome.....

JeremyEdge · Dec 24, 2011

Cool,thanks Marty.

Elias Vazquez · Dec 24, 2011

Marty,

Thanks for taking the time to write these tech. notes they have been very helpful.

Merry Christmas,

Elias

Joe Warren · Dec 24, 2011

Great articles, It would take years & years for someone to teach themselves these facts. or you can take a little time & read what Marty has printed for everyone to enjoy...

Charles Perdue · Dec 24, 2011

It only took about a year. Who do you think designed and built the first boats that were as quick or quicker thru the turns as they were down the straight.

I will give you a clue. The boats were named the BOSS. And they were the BOSS.

Jack ODonnell · Dec 24, 2011

Charles Perdue said:
It only took about a year. Who do you think designed and built the first boats that were as quick or quicker thru the turns as they were down the straight.

I will give you a clue. The boats were named the BOSS. And they were the BOSS.

That just show's how far ahead Mr. Perdue was in 1981 with the Boss boat

Tom Foley · Dec 24, 2011

Thanks and Merry Christmas Marty . Your help is always appreciated . Only wish I could zone in more but too many irons in the fire as always !!

Rick Reisinger · Dec 24, 2011

MARTY

I will never forget the 1997 Internat's here in Fort Wayne when you brought your 40 Road Runner with a .60 engine in it useing what you taught us on setting up a rigger {turn fin included } I and everyone else was shocked how fast your boat was.

If you remember the next year is when I copied your boat > with narrowed .60 RR sponsons and ran over 90mph for the first time.

The lessons I learned from you I have taught every person that has ever asked >"and a lot that have not"

Thank you my freind

Rick Reisinger

Drift Wood MBC

Fort Wayne ~ Indiana

Marty Davis · Dec 24, 2011

Charles Perdue said:
It only took about a year. Who do you think designed and built the first boats that were as quick or quicker thru the turns as they were down the straight.

I will give you a clue. The boats were named the BOSS. And they were the BOSS.

Charles:

If I remember correctly, the guy who designed the Boss', was Charles Perdue <_< Sure made us think and scratch our heads....

Charles Perdue · Dec 25, 2011

Thanks Marty, maybe I will be able to go to Charleston, looking forward to seeing you and a lot of the guys...

Charles

Marty Davis · Dec 25, 2011

Charles Perdue said:
Thanks Marty, maybe I will be able to go to Charleston, looking forward to seeing you and a lot of the guys...

Charles

I hope that you can make it. I look forward to finally meeting you.....

Charles Perdue · Dec 26, 2011

Marty, I am not only speaking for myself but for a lot of other boaters also.

We wish to thank you for taking the time and effort to put a large amount of the boating knowledge into print so that it can be shared. This info is not just for beginners but for all boaters alike. A lot of the boating knowledge that we senior boaters take for granted, you have put into your writings so that it can be retained and passed along for the benefit of everyone to read and also refer back to from time to time.

Keep up the good work.

Charles

Marty Davis · Dec 26, 2011

Charles:

Having started when we did, people had to figure out things themselves. Many of the parts and pieces, they had to design and build themselves. It was MUCH harder to get a good running hydro back then. Now, with all the boats, engines, hardware, props available people can just buy stuff and put it together. The chances of having a good running boat are very high. I have always enjoyed the WHY'S of the hobby, as you do. This information will be used by only a very few people that still want to understand the WHY'S. Most will not give the effort to apply the things that we struggled with solving over the years. Not a bad rap on the hobby, but just the way it is... Hopefully people will study and apply some of it and be happy with the results.

Your compliment comes from someone that I respect greatly.....

Ted buckley · Dec 26, 2011

MartyDavis said:
Charles:

Having started when we did, people had to figure out things themselves. Many of the parts and pieces, they had to design and build themselves. It was MUCH harder to get a good running hydro back then. Now, with all the boats, engines, hardware, props available people can just buy stuff and put it together. The chances of having a good running boat are very high. I have always enjoyed the WHY'S of the hobby, as you do. This information will be used by only a very few people that still want to understand the WHY'S. Most will not give the effort to apply the things that we struggled with solving over the years. Not a bad rap on the hobby, but just the way it is... Hopefully people will study and apply some of it and be happy with the results.

Your compliment comes from someone that I respect greatly.....

Marty & Charles, I've always been one of those WHY guys.. I've already saved your information on my Favorites tab.. Even though alot of this info. has already been covered through the years, it's good to know it's(Information) is still out there. "It was MUCH harder to get a good running hydro back then."

This is true, especially when (Back then) your trying to run against someone like: Bob Bonahum. He, for sure was a hydro boater(ahead of his time). He must of read ALL your articles - before me.

Marty Davis · Dec 26, 2011

Ted buckley said:
MartyDavis said:

Charles:

Having started when we did, people had to figure out things themselves. Many of the parts and pieces, they had to design and build themselves. It was MUCH harder to get a good running hydro back then. Now, with all the boats, engines, hardware, props available people can just buy stuff and put it together. The chances of having a good running boat are very high. I have always enjoyed the WHY'S of the hobby, as you do. This information will be used by only a very few people that still want to understand the WHY'S. Most will not give the effort to apply the things that we struggled with solving over the years. Not a bad rap on the hobby, but just the way it is... Hopefully people will study and apply some of it and be happy with the results.

Your compliment comes from someone that I respect greatly.....

Click to expand...

Marty & Charles, I've always been one of those WHY guys.. I've already saved your information on my Favorites tab.. Even though alot of this info. has already been covered through the years, it's good to know it's(Information) is still out there. "It was MUCH harder to get a good running hydro back then."

This is true, especially when (Back then) your trying to run against someone like: Bob Bonahum. He, for sure was a hydro boater(ahead of his time). He must of read ALL your articles - before me.

Ted:

Bob is a WHY guy. He was in the Indy Model Boat Club for several years. That was a great place to learn with people like Ed & Dee Hughey, Tom Grannis, Gregg Huey, Fred McBroom, Bill LeFeber, John Ackerman and MANY MANY more. I probably missed some others. Bob was like a sponge.....

Bob Blazer · Dec 26, 2011

Nice to hear from you Marty and thanks for the articles, good job. I like the statement about light boats, never too light.

Thanks Bob Blazer

Ian Inverarity · Dec 26, 2011

Marty,

When you talk about hull balance such that the boat will bounce level, is this a COG balance, or balance between COG and riding surface widths and angles? I have had the sort of balance you describe on a A/S Cobra many years ago but that is how it worked out without input from me. The hulls I have had since are not balanced like that. Can the balance of an existing hull be changed enough thru normal adjustments?

Thanks.

Marty Davis · Dec 26, 2011

nitrocrazed said:
Marty,

When you talk about hull balance such that the boat will bounce level, is this a COG balance, or balance between COG and riding surface widths and angles? I have had the sort of balance you describe on a A/S Cobra many years ago but that is how it worked out without input from me. The hulls I have had since are not balanced like that. Can the balance of an existing hull be changed enough thru normal adjustments?

Thanks.

Yes,

It is all of those components. COG, Wheelbase, Engine Placement, Top of Sponson Angle, Attack Angle, Strut Angle (by the way, I forgot that component in the Tech Article). I will need to add that.

If you take the informtion that I gave you and apply it, you will gain a huge amount in handling. Some built-in components you obviously can't change. You can, however look at what is happening and when you build a new boat, apply those things that you have observed into the new boat. This information will just make it easier to analyze.

Have you seen boats that when they hit a wave or rougher race water, the front end comes up? That is the extreme and NOT what you want, to be able to handle the rougher water.

Ian Inverarity · Dec 26, 2011

MartyDavis said:
Yes,

It is all of those components. COG, Wheelbase, Engine Placement, Top of Sponson Angle, Attack Angle, Strut Angle (by the way, I forgot that component in the Tech Article). I will need to add that.

If you take the informtion that I gave you and apply it, you will gain a huge amount in handling. Some built-in components you obviously can't change. You can, however look at what is happening and when you build a new boat, apply those things that you have observed into the new boat. This information will just make it easier to analyze.

Have you seen boats that when they hit a wave or rougher race water, the front end comes up? That is the extreme and NOT what you want, to be able to handle the rougher water.

I would like a boat that boat that does not come up at the front. Given that parameters such as "wheelbase", engine placement and so on are largely fixed by the designer it seems this may be difficult to achieve. Some boats have engine placement more rearward in relation to the sponson riding surfaces, can this sort of balance be achieved with these designs?

Tom Foley · Dec 26, 2011

I will have to say that my Series 1 Extreme 80 Twin Roadrunner with 80's or 90's in it defies all common sense at how nasty conditions are tolerated . It is AMAZING in it's ability to handle stupidly rough water and radical direction changes and just keep trucking !! No other boat I have ever had displays this characteristic so well . It must have all the right stuff !

Model Boat Turning Dynamics

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