front sponson ride pad question

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Michael Costanzo

Well-Known Member
Joined
Jan 7, 2009
Messages
1,953
after looking at a bunch of sponson bottom ride pads,was wondering why some boats are built with the lift/ride pad towards the inside and some are built toward the outside of the sponson? is this just to match the real boats or is there a benefit to the way the boat ride's or handles? i have a older hull and the ride pad is flat across. thanks,mike.
 
Mike,

flat on the right side is ok, or even anhedral, but the left sponson needs dihedral, I prefer dihedral on both, on a scale hull, with allot of wetted surface, for me the hull seams lees reactive in rough water and wakes.
 
Mike,

flat on the right side is ok, or even anhedral, but the left sponson needs dihedral, I prefer dihedral on both, on a scale hull, with allot of wetted surface, for me the hull seams lees reactive in rough water and wakes.
hi joe,both of my sponsons have dihedral on them. (Muck hull).boat runs very well in all waters. when you say "less Reactive) are you saying that it get less upset in rough water? thanks,mike.
 
Joe has good info for you. If you are wondering why the running surfaces are placed wider it is to improve stability in the corners.



As demonstrated in this wrecked boat.
mike,in the picture here,i see space between the riding pad and the turning point (outside angle) and the inside towards the tub.my pads are one flat section from tub to first turn angle towards the outside.was just wondering if the is any benifit between your design and mine? thanks for the insight. 25+ years and still trying to learn something new.mike.
 
Joe has good info for you. If you are wondering why the running surfaces are placed wider it is to improve stability in the corners.



As demonstrated in this wrecked boat.
mike,in the picture here,i see space between the riding pad and the turning point (outside angle) and the inside towards the tub.my pads are one flat section from tub to first turn angle towards the outside.was just wondering if the is any benifit between your design and mine? thanks for the insight. 25+ years and still trying to learn something new.mike.
The ride pad can be placed where ever the builder wants it to be, not to mention how wide and at what angles.

In the picture Ray posted, those are from a newer boat and are built to look somewhat scale. The sponsons on my Elam are similar in that they are made to look somewhat scale but, like in Ray's picture, the runners are actually wider than on the full sized boat. This benefits a heavier boat as it gives more lifting surface when going slow. On the other hand, a lighter boat might benefit from a narrower runner as it might not need as much lift. The only way to really know is through lots of testing in various water conditions.
 
Joe has good info for you. If you are wondering why the running surfaces are placed wider it is to improve stability in the corners.



As demonstrated in this wrecked boat.
mike,in the picture here,i see space between the riding pad and the turning point (outside angle) and the inside towards the tub.my pads are one flat section from tub to first turn angle towards the outside.was just wondering if the is any benifit between your design and mine? thanks for the insight. 25+ years and still trying to learn something new.mike.
I didn't build this boat. I think Scott Meyers did. I ended up with it when a club member became too ill to race anymore and I helped him sell his stuff.

To answer your question though I would assume it's more about the width and placement of the pad. I have had the most success with pads that are pretty close to 2 1/4" - 2 1/2" wide in boats that are in the 13-15 lb. range. My first boat was a Speedy that Ron Erickson built that weighed over 20 lbs with a K&B in it and it just sagged terribly in the turns until I added wider surfaces and Picco Bluehead to that tank and actually blew it over. I think my jaw hit my shoes when that happened. It also showed me that running surfaces also can pack air as well as the tunnel. One of the more successful guys here actually uses really deep recovery pads to block the air getting to the riding surfaces. If you were to see that boat on a set up board you would swear it would never work (his boats are also light, perfectly balanced with a really successful center section design as well). What I know is if this guy shows up he is most likely going home with the hardware.

My first Speedy was a total pig to drive. If you went left you just held your breath because it would spin or roll in a heartbeat. Having never driven any other boat I wasn't sure I could even do this because I was out of control half the time. Once John Logan built me a 15lb. boat with a Geraty/Nachweih sponson design I actually won the first race it ran in (albeit most the rest of the field was dead in the water). More to the point I had never even been in a final before that.

I only mention this because there seems to be a lot of guys who struggle in this hobby like I did initially and it's because they are trying to run boats that no one could drive. Of course while a basic design might be flawed there are also a lot of factors like weight distribution, strut and turn fin alignment, prop selection, ect. So if there are any new guys out there wanting to do this, get a boat with a proven design and not just buy the first POS you see on ebay (not to mention that the registration might already be taken). I have seen people squander a lot of money and bought themselves 15lbs. of grief that they could have spared themselves if they had just went to some races and asked questions of the people who were running well. I loaned a long-time club member and in the hobby generally for 30 years one of my boats yesterday and he had never driven a boat that stable, predictable or handled that well. Didn't even know a boat could be that easy to drive.

I wrote a lengthy article with lots of photos on rigging an 1/8th scale nitro boat that should be up on the Unlimited Northwest website in a little while. I will post a link on IW when it's there. Hopefully it will help more people be successful and want to keep doing this hobby. I am going to do other pieces on finishing and scale features, another on reassembly and initial set up and finally on testing.
 
Last edited by a moderator:
Joe has good info for you. If you are wondering why the running surfaces are placed wider it is to improve stability in the corners.



As demonstrated in this wrecked boat.
mike,in the picture here,i see space between the riding pad and the turning point (outside angle) and the inside towards the tub.my pads are one flat section from tub to first turn angle towards the outside.was just wondering if the is any benifit between your design and mine? thanks for the insight. 25+ years and still trying to learn something new.mike.
I didn't build this boat. I think Scott Meyers did. I ended up with it when a club member became too ill to race anymore and I helped him sell his stuff.

To answer your question though I would assume it's more about the width and placement of the pad. I have had the most success with pads that are pretty close to 2 1/4" - 2 1/2" wide in boats that are in the 13-15 lb. range. My first boat was a Speedy that Ron Erickson built that weighed over 20 lbs with a K&B in it and it just sagged terribly in the turns until I added wider surfaces and Picco Bluehead to that tank and actually blew it over. I think my jaw hit my shoes when that happened. It also showed me that running surfaces also can pack air as well as the tunnel. One of the more successful guys here actually uses really deep recovery pads to block the air getting to the riding surfaces. If you were to see that boat on a set up board you would swear it would never work (his boats are also light, perfectly balanced with a really successful center section design as well). What I know is if this guy shows up he is most likely going home with the hardware.

My first Speedy was a total pig to drive. If you went left you just held your breath because it would spin or roll in a heartbeat. Having never driven any other boat I wasn't sure I could even do this because I was out of control half the time. Once John Logan built me a 15lb. boat with a Geraty/Nachweih sponson design I actually won the first race it ran in (albeit most the rest of the field was dead in the water). More to the point I had never even been in a final before that.

I only mention this because there seems to be a lot of guys who struggle in this hobby like I did initially and it's because they are trying to run boats that no one could drive. Of course while a basic design might be flawed there are also a lot of factors like weight distribution, strut and turn fin alignment, prop selection, ect. So if there are any new guys out there wanting to do this, get a boat with a proven design and not just buy the first POS you see on ebay (not to mention that the registration might already be taken). I have seen people squander a lot of money and bought themselves 15lbs. of grief that they could have spared themselves if they had just went to some races and asked questions of the people who were running well. I loaned a long-time club member and in the hobby generally for 30 years one of my boats yesterday and he had never driven a boat that stable, predictable or handled that well. Didn't even know a boat could be that easy to drive.

I wrote a lengthy article with lots of photos on rigging an 1/8th scale nitro boat that should be up on the Unlimited Northwest website in a little while. I will post a link on IW when it's there. Hopefully it will help more people be successful and want to keep doing this hobby. I am going to do other pieces on finishing and scale features, another on reassembly and initial set up and finally on testing.
hi mike, thank you for this post. this boat is the opposite,it took 3rd place at a NAMBA Nats the 2nd race it ever ran, and always won race's,but i am a life long test and tuner, i am always looking for more..
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so i am going to play around with the front sponson a little and see what happens. just trying to make a good boat better.
 
I'm in the middle of building a 1/10 scale FE boat, a Master Tire U-3. Mike I remember you talking about a 1 degree anhedral angle on inside sponson and 3 degree dihedral on outside sponson. In theory you would be effectively 1 degree dihedral in the corners at speed. Any thoughts on this, I will have a balanced hull with straight shaft, no offset.

Thanks, Kevin
 
Personally, I don't think there's any performance advantage in 1/10 Scale with different sponson dihedral angles compared to just running a flat dihedral. But, that's just one guys opinion.

JD
 
In my 40 years of boat racing I have built and driven pretty much every combination of ride surfaces. I prefer flat running surfaces. If the boat is too reactive they are too wide for the weight of the boat. I have never seen a dihedral/anhedral set up work better then a properly tuned flat set up. And usually I see them do silly things at times.The flat surfaces are also easier to build and maintain. Get a good look at a Geraghty or Nachtweih boat. Running surfaces offset to the outside widen the stance of the boat making it more stable.
 
You ever going to make it out to a race Mark? Too many **** fires going on right now. You guys must be putting in a lot of OT.
 
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