Just a thought...and....don't get your panties in a knot..:-)

[Doug Smock]

Sort of on the same subject.....I have a SAW boat (under construction) that has a small flap (air brake on each rear sponson bracket) that raises at part throttle to slow the boat by aerodynamic drag and also by pushing down on the rear of the sponson to put more load on the sponson running surface. It then lowers out of the air stream at full throttle getting ready for the next pass.

I played with this idea before building it into this boat by mounting this temporally on a heat racing boat and it worked very good, much, much better than expected, very predictable.

Just a thought for some of the fast guys.

Charles

This worked out very well for Chris Harris.



I imagine the guys will come up with some cool tricks once they start needing a shovel to retrieve their boats.

 

[Charles Perdue]

Sort of on the same subject.....I have a SAW boat (under construction) that has a small flap (air brake on each rear sponson bracket) that raises at part throttle to slow the boat by aerodynamic drag and also by pushing down on the rear of the sponson to put more load on the sponson running surface. It then lowers out of the air stream at full throttle getting ready for the next pass.

I played with this idea before building it into this boat by mounting this temporally on a heat racing boat and it worked very good, much, much better than expected, very predictable.

Just a thought for some of the fast guys.

Charles

This worked out very well for Chris Harris.

Yep...that is it.

 

[Andy Greene]

Sort of on the same subject.....I have a SAW boat (under construction) that has a small flap (air brake on each rear sponson bracket) that raises at part throttle to slow the boat by aerodynamic drag and also by pushing down on the rear of the sponson to put more load on the sponson running surface. It then lowers out of the air stream at full throttle getting ready for the next pass.

I played with this idea before building it into this boat by mounting this temporally on a heat racing boat and it worked very good, much, much better than expected, very predictable.

Just a thought for some of the fast guys.

Charles

This worked out very well for Chris Harris.

Beat me too it

Hope your well Doug . gonna do Sowega in the fall ?

And just when do we get to see The quiet HammerHead H20 member , Mr Harris wet a boat ???

The bar is raising and I KNOW he wants it.

I kinda like the idea of some short beams on the top end of said run up area , but just for chits and giggles and bragging rights at a race.

The current 330 should stay for SAWS records imho - Think about it , there have been plenty of one way passes over the record that where never backed up.

Its a total effort 2 x

Your just gonna need more room .............

There where several killer spots the late Ron Green was looking into that never matured before his passing that would be perfect in the Fl area .

 

[bzubee]

Andy here is your killer spot in Huntsville over 750 feet on one end and over 800 feet on the other end for run out or run up with 330 feet in between.

View attachment 74098

 

[Bob Morton]

Portersville Pa has plenty of room per IMPBA rules for SAW. We will continue to offer a five day event at $25.00 for the event

Come and go as you please. Preregistration,have your paper work ready to be signed.

May 9th thru May 13th 2016. Check IMPBA web sit for details.

Join us for the GO FAST RECORD TRIALS

Bob Morton

 

[Andy Greene]

Andy here is your killer spot in Huntsville over 750 feet on one end and over 800 feet on the other end for run out or run up with 330 feet in between.

You guys have it going on in Huntsville for sure Bill , nice site no doubt.

Ron had a couple he was working on in Fl that would have been very nice sights to add to whats already offered.

Huntsville - Legg Lake - Blue Lake - ect . If I ever hit the lotto there will be one Bad Azz event in Central Fl , rest assured

 

[lohring]

A water brake will be lots more effective than an air brake. Big boats push a cylinder into the water with hydraulics. Notice how quickly a boat that flips stops. A water brake should approach this in a controlled way. Consider using the servo that actuates the air brake above to push a pair of rods in the same position into the water.

However, that leaves the drag race problem. Even at 100 mph the Leg Lake run up distance is short. Electrics have the highest power to weight (at this time) so it's less of a problem for them. Our really heavy GX2 boat was fairly slow to accelerate despite having nearly 9 (detuned from 12) hp and water injection into the pipe. See below. The GPS signal lags the rpm due to the slow update rate of that vintage GPS. The two graphs should overlap. Like all drag racing, power to weight is what matters most.

Lohring Miller

 

[Grimracer]

Rod,

I for one (no.. I am not a RT guy) but do like contests.. Like the challenges involved with what is written. There are limits to all contests and this is no different.

Its like some of the classes we race.. (Sport Tunnel or Sport 40).. they too have limits that we need to work around. To me this is what make this so much fun.

9 cents.. its all I got!

Grim

 

[DON MAHER]

Guys,

I think what Rod & Tommy are referring to is the safety of trying to run boats that are capable of speeds of 150+mph on our existing courses. Believe me at 140mph on Legg Lake you had better be on your game when you shut down or you will be on the beach!!! We are not talking 100 - 120mph boats here, 140 - 150mph is a whole different ball game!!!

Andy, no one has made a one way pass over the 142mph record of Tylers in NAMBA to date. You are right when you say we need more room, but you can't make the water bigger. BUT you can make the run up & shut down longer. And Legg Lake has almost 800ft. of both.

Don

 

[KenOlvis]

......

 

[Geraghty]

Guys,

I think what Rod & Tommy are referring to is the safety of trying to run boats that are capable of speeds of 150+mph on our existing courses. Believe me at 140mph on Legg Lake you had better be on your game when you shut down or you will be on the beach!!! We are not talking 100 - 120mph boats here, 140 - 150mph is a whole different ball game!!!

Andy, no one has made a one way pass over the 142mph record of Tylers in NAMBA to date. You are right when you say we need more room, but you can't make the water bigger. BUT you can make the run up & shut down longer. And Legg Lake has almost 800ft. of both.

Don

Don,

Exactly.....With what we have witnessed in the past 10 years I believe we will all agree that the speeds are going to increase....

Tommy and I longer have a dog in this fight and we really do not care which way it goes....we were just trying to generate some discussion and see what people thought...

This subject has generated a lot of opinions but very few suggestions on how to retain the viability of current race sites and that was the original question....

I suspect this thread is pretty much dead until somebody has to retrieve their boat with a shovel or use a net to pick up the pieces....or heaven forbid somebody gets hurt by a 150+ mph boat exiting a pond...

With the performance increases we have seen in gas and FE the speeds are going to continue to increase........I can remember very vividly when 100 mph was a very big deal....

Don't get me wrong , challenges are great but at times they can and will produce unintended consequences......

Tommy & Rod

 

[DON MAHER]

Rod,

I used 150mph example because I know one boater who has done this more than once on gps. I really feel the next few years will see speeds close to 160mph in Europe because they have a couple very long courses. To see those speeds on our existing courses there are two choices, 1 Some type of break or 2 Shorten the timed distance, maybe both. jmho

Don

 

[Mark Bullard]

One thing I noticed at the last record trial was the slow down. On a fuel boat the slow down is much better. You let off the throttle the boat slows down pretty quick. The prop will wind down the motor. With the electric's the slow down is different. If you let off the throttle the prop will do everything it can to stop. Why the ESC has no free wheel feature that I know of. And the voltage that is generated in the slow down will take out a ESC. Very common problem in VFD's. But VFD have the protection to not blow up the drive. They do have controlled freewheel and braking features. A ESC does not. So with that what I saw was a long slow down by the driver to control the back generating voltage.

 

[Grimracer]

Guys,

I think what Rod & Tommy are referring to is the safety of trying to run boats that are capable of speeds of 150+mph on our existing courses. Believe me at 140mph on Legg Lake you had better be on your game when you shut down or you will be on the beach!!! We are not talking 100 - 120mph boats here, 140 - 150mph is a whole different ball game!!!

Andy, no one has made a one way pass over the 142mph record of Tylers in NAMBA to date. You are right when you say we need more room, but you can't make the water bigger. BUT you can make the run up & shut down longer. And Legg Lake has almost 800ft. of both.

Don

That may be.. he just did not state that very clear..

Grim

 

[RaceMechaniX]

One thing I noticed at the last record trial was the slow down. On a fuel boat the slow down is much better. You let off the throttle the boat slows down pretty quick. The prop will wind down the motor. With the electric's the slow down is different. If you let off the throttle the prop will do everything it can to stop. Why the ESC has no free wheel feature that I know of. And the voltage that is generated in the slow down will take out a ESC. Very common problem in VFD's. But VFD have the protection to not blow up the drive. They do have controlled freewheel and braking features. A ESC does not. So with that what I saw was a long slow down by the driver to control the back generating voltage.

Mark,

Just to elaborate on the topic, many of the ESC's due have active or passive freewheeling however the motor selected has a greater effect. The slotless motors have very low cogging detent compared to the more traditional distributed wound stators, hence they coast a long ways like a nitro boat would. Most of the SAW riggers I run use the slotless motors. The benefit being you can lift immediately and it will coast down smoothly. With the high detent motors you do have to be careful when letting off as the cogging torque can stall the prop enough to cause the tail to lift and you stuff. A little more throttle finesse is required.

One could set a throttle expo to slow the decel throttle return to zero, but I think most would have more panic moments than benefits from such a laggy throttle return.

Tyler

 

[Mark Bullard]

Fair enough Tyler. I just don't keep up with the ESC's like you do. And I was just looking at the outside of the box. I do work with a lot of VFD's and motors.

 

[John Finch]

I see the point of having more run up room, But.....Tylers record of 133 mph only took 1.6 seconds to go 330 feet. If you cut the timed distance to 200 feet you only extend run up distance by 65 feet and run down distance by 65 feet. So, you only have 65 extra feet to slow down So, the reality is.........Tyler gets 3 tenths of a second more time to slow down before hitting the bank. That is not worth the effort to shorten the timed distance!

John

 

[Geraghty]

I see the point of having more run up room, But.....Tylers record of 133 mph only took 1.6 seconds to go 330 feet. If you cut the timed distance to 200 feet you only extend run up distance by 65 feet and run down distance by 65 feet. So, you only have 65 extra feet to slow down So, the reality is.........Tyler gets 3 tenths of a second more time to slow down before hitting the bank. That is not worth the effort to shorten the timed distance!

John

John,

Hell , why don't we just make the SAW trap 500' and make it a real challenge for SAW time trials......

There would not be any return passes because everything would be on the beach...

200' was just a number we picked out of the air to generate discussion on retaining the viability of existing sites.....

Just like Maher said the NHRA lights are only 60' to get speed readings...

If a change was ever to happen in the distant future , RC boating should pick a trap length number that makes sense......Whatever that might be....

Rod

 

[bzubee]

Right now I would imagine the trap distances match up with the 1/3 mile oval course buoy line and that gives a good reference for the drivers of where the traps are located while driving. Other wise if changed all sites would need to have another point surveyed which would be a PIA for many clubs since you still need the NEW paper work submitted and signed.

 

[Andy Greene]

Im gonna say it because no one else has , or chooses to ignore it, either way ,

The speeds have gone up , no doubt - and the need for longer runup/shutdown room may or may not need to be addressed , but what I have not heard one word about is safety due to said speeds.

Sure longer runup/shutdown will be "safer " if a boat doesnt hit the bank because it couldnt turn or slow down , But what about when it leaves the lake on its own (blowoff) at 120 - 130 - 140 ++ ???

Its happened and anyone that ever saw Jeorges boat leave Legg Lake after a blow off chasing the record a few years back will attest -

That fricking thing went a hell of a long way - AT SPEED - scarier than hurting your boat due to lack of rundown room IMHO

I dont think I coulda thrown that boat as far as it went, all the runoff in the world would not have saved someones life in that case.