Stance

[T.S.Davis]

Sorry if this has been asked before guys.

What is the theory on the width of the sponson stance? I noticed that a JAE45 is shown at 22.4" where as a JAE45 twin is 24". Made me realize how ignorant I am. I really don't understand how these conclusions are made. What would I watch for to tell me I'm too narrow too wide?

Is there a rule of thumb or is it a wild a$$ guess for everyone?

 

[RodneyPierce]

Subscribed to find out this answer. Good question!

 

[javier molina]

from my understanding the wider the stance the more stable the boat will be when its haulin the mail.

 

[timothy johnson]

Another theory is that Rod G who designed the JAE 45 said that 24" is a good number, when in doubt check with the people who designed the boat.

 

[Mike Larson]

Theres alot of theory involved.... wider/more stable to a point.... the pivot point on the fin factors in there, and all kinds of neat engineering principles that, are above me.... Help us out Rod?.... the boat'll gain speed in you tighten the stance... but too much and it'll barrel out eventually...... alls i can say is... stay with what the Jae guys have on the sheet.... theyve done the work... my 45 boat goes.... if i could keep a dang radio in it...... 'luck.... Mike

 

[T.S.Davis]

I'm not building a JAE. That was just an example. Some of my geometry is similar but I'm 6s2p LiPo with Neu power. I have 3 or 4 different winds and multiple battery combos I'll likely try. Thinking mid 70's in oval trim but that may be conservative.

Stability from width makes sense. Hadn't thought about pivot point. That makes even more sense given the difference in width from a single to a twin that Rod uses. You're changing the pivot point with the wider stance making it easier to turn the extra weight of a twin. Speculation on my part. Heavier boat........wider stance?

Honest, this isn't my first boat or my first rigger. I just wanted to understand the criteria the big dogs use. Might be grey matter not for public consumption. I understand if that's the case.

It feels like a best guess then adjust based on the performance. Stability and turning torque may be all there is to watch for.

 

[Geraghty]

Sorry if this has been asked before guys.

What is the theory on the width of the sponson stance? I noticed that a JAE45 is shown at 22.4" where as a JAE45 twin is 24". Made me realize how ignorant I am. I really don't understand how these conclusions are made. What would I watch for to tell me I'm too narrow too wide?

Is there a rule of thumb or is it a wild a$$ guess for everyone?

There really isn't much theory here.....it is simple geometry, physics and common sense applies here........the wider the sponsons the more stable the boat.........

The JAE rides so free on the water with virtually no Coanda or Bernoulli effect that there is no outside hydrodynamic forces being exerted on the boats performance....That is the reason

there are no sponson AOA adjustments required on the boat......

I know I am going to meet some resistance on that statement.....but..........The JAE team has always said from day one,take everything you think you know about traditional rigger set-up

and flush it out of your mind....It does not apply to the JAE principle of design.......

To the best of my knowledge and to date, the JAE team has yet to have a sponson stance that was too wide on a JAE boat......

Excuse me but this would be a good time to say this again..........

There have been a ton of JAE's built and run and 98+% of the JAE's built were built by newbies to riggers and most are non-racers.........to a man,every JAE built by the instructions comes

off the stand fast and competitive and leaves their owners with smiles on their faces.......

There isn't anything more frustrating to spend hours and hours building a boat and have it not launch or require hours of testing to get it to make a lap around the pond......

99% of the time I get a question or complaint about a JAE's performance,I eventually find out the builder has incorporated changes into the build thinking he knows more about the boat than the JAE team......

This is where traditional rigger thinking infects the JAE build process and it comes back to bite the builder in both cheeks.......

For example:...sponson or ski bottom changes....adjustable sponsons.......adjustable struts or strut depth.........shortening the rudder........too much rudder throw or rate......

narrower sponson stance........moving the motor forward.........just to mention a few.....

RE: Fin pivot point......The principals behind the physics of the fin/turning pivot point remain the same no matter how wide the sponsons are.....this is primarily a driving style decision

that the driver will make....The only thing that really counts on a JAE's fin is you have enough fin size and curl to eliminate any boat slide in the corners........

I hope this helps.....once again 1-715-926-6096 if you want to talk about this......

 

[Don Ferrette]

This JAE commercial advertisement has been brought to you by........................... :lol: :lol: :lol: :lol: :lol:

Sorry Rod just couldn't resist pokin' a little fun at ya.

 

[javier molina]

Great post Rod G.

 

[lohring]

It's even simpler than that with apologies to Rod. My Raptor P spec electric kept getting faster as we ran better props and equipment but It started dumping in the corners. Wider sponson stance was the answer along with a new turn fin. There is very little down side to a wider stance within reason.

Lohring Miller

 

[T.S.Davis]

I have two Jae. One is a scaled version that is 27". The other is the FE version but the tub is shallower. Both run pretty well. Need to put the ski back on the 32" though. This new one is different. I've in corpororated some cues from the reesor riggers.

 

[Andy Brown]

Sorry if this has been asked before guys.

What is the theory on the width of the sponson stance? I noticed that a JAE45 is shown at 22.4" where as a JAE45 twin is 24". Made me realize how ignorant I am. I really don't understand how these conclusions are made. What would I watch for to tell me I'm too narrow too wide?

Is there a rule of thumb or is it a wild a$$ guess for everyone?

There really isn't much theory here.....it is simple geometry, physics and common sense applies here........the wider the sponsons the more stable the boat.........

The JAE rides so free on the water with virtually no Coanda or Bernoulli effect that there is no outside hydrodynamic forces being exerted on the boats performance....That is the reason

there are no sponson AOA adjustments required on the boat......

I know I am going to meet some resistance on that statement.....but..........The JAE team has always said from day one,take everything you think you know about traditional rigger set-up

and flush it out of your mind....It does not apply to the JAE principle of design.......

To the best of my knowledge and to date, the JAE team has yet to have a sponson stance that was too wide on a JAE boat......

Excuse me but this would be a good time to say this again..........

There have been a ton of JAE's built and run and 98+% of the JAE's built were built by newbies to riggers and most are non-racers.........to a man,every JAE built by the instructions comes

off the stand fast and competitive and leaves their owners with smiles on their faces.......

There isn't anything more frustrating to spend hours and hours building a boat and have it not launch or require hours of testing to get it to make a lap around the pond......

99% of the time I get a question or complaint about a JAE's performance,I eventually find out the builder has incorporated changes into the build thinking he knows more about the boat than the JAE team......

This is where traditional rigger thinking infects the JAE build process and it comes back to bite the builder in both cheeks.......

For example:...sponson or ski bottom changes....adjustable sponsons.......adjustable struts or strut depth.........shortening the rudder........too much rudder throw or rate......

narrower sponson stance........moving the motor forward.........just to mention a few.....

RE: Fin pivot point......The principals behind the physics of the fin/turning pivot point remain the same no matter how wide the sponsons are.....this is primarily a driving style decision

that the driver will make....The only thing that really counts on a JAE's fin is you have enough fin size and curl to eliminate any boat slide in the corners........

I hope this helps.....once again 1-715-926-6096 if you want to talk about this......

"The JAE rides so free on the water with virtually no Coanda or Bernoulli effect that there is no outside hydrodynamic forces being exerted on the boats performance....That is the reason

there are no sponson AOA adjustments required on the boat......

I know I am going to meet some resistance on that statement.....but......"

Yes of course you are Rod. I watched some really nice running 21 JAE's at the Brandon race last week. Both in the hands of acomplished and seasoned boat racers. One was cruising along really nicely in the smooth water.....then it encountered a little chopped in the middle of the front straight. That chop exerted all kinds of hydrodynamic forces on that JAE that quickly put an end to that run. :mellow:

The 12'' wide SGX has won 2 out of 3 florida races this year the 3rd going to Foley's Roadrunner, also about a 12" wide boat. JAE's were present at each race.

So to get back on topic....looks like any stance will work as long as you work on the corasponding details.

 

[Grimracer]

Off subject a tick but never the less..



By far the best running JAE I have ever seen run is David Preusse's 45. (not sure its “stock” or not)

Its far and ahead the best in all aspects of what we like in a Hydro. Having said this I have seen others that are OK too.. just not as good as Daves… truth is.. not even close.

Just to qualify.. That I have personally seen..



One of the deals with Dave for those that don’t know him.. he can tell you EVERYTING about the prop on the boat.. what he has run it on, what date he had to re-touch a blade.. heck.. he even knows what date he bought the thing.. (I would not be surprised if they all got birthday partys).. and I mean that in a good way..



Dave IS.. PROPS!



Dave is one of the best at putting a prop under a boat. Seems to me his Hawk was LIGHTING FAST TOO!



I don’t feel (Its just me) the JAE delivers a knock out blow in hydro design. Im just not seeing it.



As long as most of us have been doing this.. we all know how critical the prop is..



If I was a betting man.. and looking to ante up.. it would not be on the typical JAE.. (unless It was Daves boat.. with Dave on the sticks and his prop under the boat. Add in one of those nasty Nelson motor he has and GOOD GOD!).



And to get back on subject.. its that old “trade off” I have tried a number of offsets and always found the turn fin to be WAY more critical than the sponson stance/offset. Almost to the point (within a reasonable stance) that is does not matter.



BTY.. I have found all successful hydros to have a “reasonable” stance!



Grimracer

 

[T.S.Davis]

What I'm taking away from this so far is that the stance isn't where all the magic happens. It's all those other things to worry about.

My JAE needs more time spent to really get the most out of it. It does run really free even without the center ski. Very low amperage even with some pitch.

We'll see how this one goes. The tub I'm building may produce too much lift of it's own. I'll post some pics when I get it closer. It being a heavy FE tank changes it up a bit too.

Has anyone ever taken the time to compare the weight of a .45 and it's fuel to a 6s2p FE setup? I wonder about that. The speeds should/could be simliar in oval trim.

 

[Andy Brown]

What I'm taking away from this so far is that the stance isn't where all the magic happens. It's all those other things to worry about.

My JAE needs more time spent to really get the most out of it. It does run really free even without the center ski. Very low amperage even with some pitch.

We'll see how this one goes. The tub I'm building may produce too much lift of it's own. I'll post some pics when I get it closer. It being a heavy FE tank changes it up a bit too.

Has anyone ever taken the time to compare the weight of a .45 and it's fuel to a 6s2p FE setup? I wonder about that. The speeds should/could be simliar in oval trim.

"What I'm taking away from this so far is that the stance isn't where all the magic happens. It's all those other things to worry about."

I think you are on track with that thought.

A good 45 nitro rigger will be 5.5 to 6.0 pounds. I full tank of 60% nitro about 1 pound.

A couple of accomplished electric guys have set up our 45 SGX and they are running between 75 and 80 mph, which is the race speed of a good 45 nitro rigger.

 

[SayMikey]

I love my JAE it just keeps getting better,and now I know who to bum props from I may get it faster yet.

 

[T.S.Davis]

I've seen some FE SGX. Twaits ran some wicked fast heats on our pond. PAGS boat is just as fast but he can't hold a lane like Dougie can.

I ran against one of Reesors old riggers up in Canada with my whip in open hydro. That thing is just stupid fast. I got him in one heat but it had nothing to do with speed. Super fun heats.

 

[Ian Inverarity]

Off subject a tick but never the less..

By far the best running JAE I have ever seen run is David Preusse's 45. (not sure its “stock” or not)

Its far and ahead the best in all aspects of what we like in a Hydro. Having said this I have seen others that are OK too.. just not as good as Daves… truth is.. not even close.

Just to qualify.. That I have personally seen..

One of the deals with Dave for those that don’t know him.. he can tell you EVERYTING about the prop on the boat.. what he has run it on, what date he had to re-touch a blade.. heck.. he even knows what date he bought the thing.. (I would not be surprised if they all got birthday partys).. and I mean that in a good way..

Dave IS.. PROPS!

Dave is one of the best at putting a prop under a boat. Seems to me his Hawk was LIGHTING FAST TOO!

I don’t feel (Its just me) the JAE delivers a knock out blow in hydro design. Im just not seeing it.

As long as most of us have been doing this.. we all know how critical the prop is..

If I was a betting man.. and looking to ante up.. it would not be on the typical JAE.. (unless It was Daves boat.. with Dave on the sticks and his prop under the boat. Add in one of those nasty Nelson motor he has and GOOD GOD!).

And to get back on subject.. its that old “trade off” I have tried a number of offsets and always found the turn fin to be WAY more critical than the sponson stance/offset. Almost to the point (within a reasonable stance) that is does not matter.

BTY.. I have found all successful hydros to have a “reasonable” stance!

Grimracer

The best JAE I have seen is the boat Aaron Alberico used to run until it was destroyed in a crash. This was a boat built by Kently Porter, and while it certainly looked like a JAE and has many of the design features of the JAE21 kit/plans, it was not the same. The sponson widths, angles, tub clearance, engine placement, even stance was different to the kit JAE. Compared to Aaron's boat I feel my kit boat runs too light at the front. At a race meeting last year the wind came up in the first turn, mine and all the other JAE's in the field crashed in that turn, even tho we were not going fast, while Aaron was able to get thru and win the race unopposed.

My boat has stunning turn performance in turns on good water but when the water roughs up it need a lot more rudder to keep turning, even with the Preusse turn fin. In my opinion this degrading of turn performance is due to too much lift at the front. And I have blown the boat off a number of times hitting the wakes of other boats.

I do think they are an advance in design however. Compared to my previous 21 outrigger it always launches even if the prop is too big to get on pipe. And is much less sensitive to the quality of launch. The JAE is also able to turn at full throttle in my tiny test lake, the old boat was fine on a course but not on my test lake. Due to the low drag design and very low slip angle in turns this boat is able to pull enough G's in the turns (due to maintaining corner speed) that the engine cannot pull fuel when the main tank gets less than 1/2 full, a phenomenon I have never found before.

Without non-trips the boat relies on the low slip angle that comes from the larger than usual turn fin, if the turn fin doesnt hold the boat it will crash. The plan/Zippkit turn fin is larger than the fin I had on my 45SG, the Preusse fin has even more area. With the right balance of lift and turn fin it should be a very good design.

 

[T.S.Davis]

Like I said, I have two JAE. Found an old pic of one of them. It's the smaller of the two. Had to modify the booms to spot the batteries.

 

[Charles Perdue]

This is one of the instances when there is more than one right answer.

When we were running the narrow stance boats, we were using a wider running surface on the sponsons. The reason being was to counteract the engine torque trying to push the right sponson down on launch, hard accreleration, and in the corners. As we went to narrower sponson running surfaces, the stance was widened to keep from having a problem with the torque roll. This allowed us to use props with larger diameters also.

At least this was my experience.

Charles