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View Full Version : Rigger Sponson Angles From Side to Side? Not AOA.



Meniscus
06-03-2009, 11:27 AM
I have a few questions for those running a rigger. I have noticed that many of the hydros I've seen feature a ride pad on the sponson that is slightly lower towards the center of the boat. I was wondering if this applies to riggers as well. I notice some have this feature and others do not.

This is not a question of AOA (Angle of Attack). My question is regarding the degrees of which one section of the ride pad sits lower in the water, towards the center of the hull.

I hope my question is clear and I'm looking forward to seeing everyone's input. If you have a picture of any of the riggers you run showing this angle, please post as well.

Thanks! :thumbup1:

jcald2000
06-04-2009, 05:27 AM
1 to 2 degrees of dihedral is common for a race water boat. 0 degrees for a SAW boat. Be prepared to change either, different setups and boats like different dihedral.

Meniscus
06-04-2009, 08:13 AM
OK, this is my understanding. For SAWS, no angle is necessary. When oval racing, the inside edge is set 2 up to 3 degrees lower in the water. This helps the outside sponson "slide" on the outside edge rather than catching which would cause a flip, or at least contribute to it. This also helps the inside edge of the inside sponson to the turn, catch the edge, thus helping to provide a surface to turn against, much like a turn fin.

Do I have this right?

longballlumber
06-04-2009, 08:31 AM
Meniscus,

Are you a member of intlwaters.com?

There is an entire thread about dihedral and anhedral angles. Some of the most experenced builders of nitro riggers discuss what your asking about.

http://www.intlwaters.com/index.php?showtopic=20987

Meniscus
06-04-2009, 09:36 AM
Thanks for the link! I am a member, I have been a member, I'm not a member, who knows.

It seems like either I don't get approved by the admin or they approve me and ditch me in a few days. I've done this 4 or 5 times now. I think it may be due to my last name seeming to be B.S., LMAO!

I will once again try to register and see how it goes. I really appreciate the link and can't wait to see the discussion.

Meniscus
06-04-2009, 10:48 AM
I can't seem to access that thread, but I can see everything else.

longballlumber
06-04-2009, 10:58 AM
Try a search on "deadrise"

J Solinger
06-05-2009, 02:03 AM
I've seen some very geometricly complex riggers. One that comes to mind used rear ride shoes so it had 4 ride pads. Each pad had a different height, dihedral angle and AOA. It worked well but it was a very hard boat to set up. The idea was to keep tension forces at work in all 4 corners of the hull at about 70 mph, in straights and turns. When I started designing my oun rigger hulls I took all of this stuff out. I run all sponson and ride pads flat with no dihedral. I then shape the deck so it won't lift. I have had very good results with this, I have changed the sponsons on my sport scale hydros and they improved to.