.21 sponson specs

[anthony_marquart]

IT came up in the other thread,.. I would like to hear more opinions.

What sponson widths are working for you guys and what are their traits at launch and at speed.

I'm running 32mm width, 167mm ride surface length and 4deg AOA. I run a 1/16 or so over hang and no dihedral. I set the boat up so the hull runs flat.

This works real well.. it plows bit up to about 3/4 speed,.. but is really fast and stable at speed,.. I also run a center ski rear.. I also like to add shingles,.. I think they help on launch..

What you guys got? I would like to know what the eagles and RR's have as well..

THanks

 

[Charles Perdue]

Anthony, tell me more on how you have the shingles set up. A pic would be helpful.

 

[anthony_marquart]

I'll see about a pic,.. but it's just a piece of ply about 1.5in long 1/8 think at the thickest point, tapered to a point at the forward side. I place these end to end to end with the last one ending at the trailing edge of the sponson. These are the full width of the sponson.

 

[anthony_marquart]

No input guys?,.. come on..

 

[Chris Wood]

1" wide ( i think you can go narrower ) ( On a 21 boat )

5 degree's attack angle

if it is plowing it is dragging and that ain't any good

 

[anthony_marquart]

I would think at 5deg it would plow even more...

 

[RodneyPierce]

The more angle, the looser the boat is on the water. So in theory, more angle should help with the plowing I would think.

 

[Chris Wood]

you are correct rod

the less the angle say 1 2 or 3 degree's the more the PLOW effect

 

[Ron Zaker Jr]

I would think at 5deg it would plow even more...

why even ask for input

 

[anthony_marquart]

What do you mean "why even ask for input".. Is it not the purpose to talk about it and ask questions? Physics tells us that the higher aoa you the closer the forward load gets to horizontal, which would be total plowing..

I ask for input because I want to learn,.. what was the purpose of your comment? The JAE runs less than 5deg AOA

 

[user 115]

Sheesh, Zaker.. Have a heart!!!

 

[Ron Zaker Jr]

What do you mean "why even ask for input".. Is it not the purpose to talk about it and ask questions? Physics tells us that the higher aoa you the closer the forward load gets to horizontal, which would be total plowing..

I ask for input because I want to learn,.. what was the purpose of your comment? The JAE runs less than 5deg AOA

PEOPLE ASK FOR INPUT,THEN WHEN YOU TELL THEM THE TESTED ANSWER, THEY FIGHT IT. AND YES I KNOW WHAT THE JAE AOA'S ARE.

 

[Ron Zaker Jr]

Sheesh, Zaker.. Have a heart!!!

Yeah like I don't help people.

 

[user 115]

Sheesh, Zaker.. Have a heart!!!

Yeah like I don't help people.

Lots of Love, Ron!

 

[TimothyJones]

Ok,

So with tub level and a protractor(for instance) If you raise the front boom that increases the AOA?

I have never checked that on mine, so that means I suck>>>> But anyway!!!

Tim

 

[RodneyPierce]

Tim, yes. Or vice versa. Lowering the rear boom with increase the AOA, raising the rear boom will decrease the AOA. But something to remember, is this also changes the angle that the tub rides when setting on all riding surfaces. I just did a little test on a rigger file I have here, and appears that dropping the rear boom .063 and leaving the front in the same place, on this particular boat, made the rear of the ski set off the flat surface by .080. So when the rigger is riding on all riding surfaces, the tub angle also changed. This gave me an increase in AOA by 1* and changed the tub from riding level, to a slight upward angle towards the front (but still less then 1*) so I doubt it would really matter much there.

 

[TimothyJones]

Thats what I love about this hobby. There are always things to check,do and try.

 

[shoboat]

Rodney,

I would try not to adjust the rear boom tube on a hydro unless you

need to reduce your angle of attack. It will change your tub ride height.

To increase the angle of attack just move your front boom tube up.

This will make most hydros run a little faster if they are to tight on the

water. The road runners can use this adjustment and it will wake them

right up. Most hydros are running too little Angle of Attack and they are

always looking for more speed. This is the way to achieve it with some

propeller work also. Lighter on the water will allow you to pull a little more

propeller. You will need a great digital angle finder for these adjustments.

Have Fun Testing,

Mark Sholund

 

[Niklas Edlund]

You can check the ride surfaces AoA without any fancy digital gauge also...

http://ne-stuff.blogspot.com/2010/11/outrigger-set-up-board-and-aoa-charts.html

 

[Grimracer]

I tested a bunch.. the boat (Ninja) has 3 US-1s to prove it! lol

And truth is I would not have had it any other way.. because I learned A TON about other aspects of the boat doing sponson AOA testing..

And then after all my hard work and labor..... I was rewarded with a good prop from a fellow racing buddy.(had no clue it was coming). I then went on to beat him in an event.

The real reward.. EARNING IT!.. not asking for it.. I have a sneaky suspicion that was Rons comment in a nut shell (look, Im in a nut shell!)

Grim