Confused About Scale Offsets

[Ken Smith]

Hey All,

I'm a bit confussed about which side the offset should be for 1/8th scale hydros. I've always thought it should mimic the full size boats with an offset to the left (if you are looking at the boat from the rear facing the front). However, I've seen a few scales with the offset to the right. Is this decided by club rules? I have two scales that raced here in the Northwest and both have offests to the left. I have an ML Boatworks kit and it appears the numbering of the toytabs is setup for a right offset. Can anyone clear this up? Thx

 

[Pat Bristol]

I cant quote the rule, I would have to look it up, but scales that run clockwise run the wider sponson and the cowl/center section on the left side to use the natural weight of the boat/engine to hold the outside sponson down on the water to help counter the engine torque and have better running hull balance side to side.

 

[hgatjens]

The rule in RCU is that you can do it either way. You can match the real boat for standing appearance, or you can reverse the offset for running "appearance" sake and for performance issues. The one thing you can't do is have no offset.

 

[SayMikey]

I have never seen any advantage either way just a builders choice

 

[Ken Smith]

Ok. Thanks Harry for the RCU rule. Does the larger sponson also apply? That is, if the offset is to left then the larger sponson MUST be on the left as well and right offset would have the larger sponson to the right? Or can the offset be opposite to the larger sponson? Confusing Thx

 

[jwo]

Ok. Thanks Harry for the RCU rule. Does the larger sponson also apply? That is, if the offset is to left then the larger sponson MUST be on the left as well and right offset would have the larger sponson to the right? Or can the offset be opposite to the larger sponson? Confusing Thx

The sponson does not have to match the real boat. We turn right so the larger sponson is on the left. The offset does not matter has to what side it is as long as if the real boat had an offset the model must have. Running both left and right offsets, I have not really seen a difference. I do however center the engine and shaft between the tunnel. The real boats also cener the shaft.

 

[Ken Smith]

Ok. This makes a bit more sense now. I was always under the impression the big boats had the larger sponson on the left. However, just looked at some pics of full size boats and the larger sponson is on the right. I guess I just figured they would be on the left to move the weight closer to the left to assist with turning left. Maybe with the left offset a larger right sponson is required to balance the boat? So larger boats have left of center offset with right large sponson. Scales can offset in either direction but large sponson must be on the left (when racing clockwise). Ok I think I got it. Thanks

 

[hgatjens]

The real boats always have the larger sponson on the outside when turning. While not a rule, if you reverse the offset, you should also reverse the large sponson side.

 

[Hydro Junkie]

I have to agree with Harry on this one. If the wide sponson is on the left, offset should go to the right if you're mirror imaging the full sized boat. Granted, this is a personal taste decision and not everyone is going to want to take the time to change a frame or two to make it happen

 

[hugh hargett]

Harry,If every scale has to be offset to be legal explain the shovels? All of them dont have asymmetrical sponsons and offset ,so hows that workout?Lastly if it doesnt matter why do it? Seems like it goes back to what I said on the "who made this hull" thread. The overall displacement of the hulls is so much smaller with rc's that the issues that dictate sponson placement on a real boat dont show up so much in RC boats . People naturally build things symmetrical, so "offset" had to be a design upgrade somewhere back in the history and development of hydroplanes. In other words I cannot believe "all" hydros had it, so how could it be a rule you must have offset? :huh:

 

[jwo]

Harry,If every scale has to be offset to be legal explain the shovels? All of them dont have asymmetrical sponsons and offset ,so hows that workout?Lastly if it doesnt matter why do it? Seems like it goes back to what I said on the "who made this hull" thread. The overall displacement of the hulls is so much smaller with rc's that the issues that dictate sponson placement on a real boat dont show up so much in RC boats . People naturally build things symmetrical, so "offset" had to be a design upgrade somewhere back in the history and development of hydroplanes. In other words I cannot believe "all" hydros had it, so how could it be a rule you must have offset? :huh:

ONLY SCALES OF BOATS THAT ARE OFFSET. Same goes for NONSYMETRICAL SPONSONS. IF THE REAL BOAT IS OFFSET AND/OR HAS NONSYMETRICAL SPONSONS THE MODEL MUST COMPLY. You are able to build it just like the real one or you can mirror it. In other words you can build it for turning right.

 

[Dasboatman]

Hey John,

I believe you are quoting R/C Unlimited rules for the requirement of offset and nonsymmetrical sponsons. I don't believe that requirement exists under NAMBA or IMPBA Scale Unlimited rules. CHEERS !!! Bob

 

[hgatjens]

Harry,If every scale has to be offset to be legal explain the shovels? All of them dont have asymmetrical sponsons and offset ,so hows that workout?Lastly if it doesnt matter why do it? Seems like it goes back to what I said on the "who made this hull" thread. The overall displacement of the hulls is so much smaller with rc's that the issues that dictate sponson placement on a real boat dont show up so much in RC boats . People naturally build things symmetrical, so "offset" had to be a design upgrade somewhere back in the history and development of hydroplanes. In other words I cannot believe "all" hydros had it, so how could it be a rule you must have offset? :huh:

ONLY SCALES OF BOATS THAT ARE OFFSET. Same goes for NONSYMETRICAL SPONSONS. IF THE REAL BOAT IS OFFSET AND/OR HAS NONSYMETRICAL SPONSONS THE MODEL MUST COMPLY. You are able to build it just like the real one or you can mirror it. In other words you can build it for turning right.

What I meant, and obviously did not make clear, was that all real hydros that are offset, and have one sponsor larger then the other, are offset to the outside sponson. This practice did not start until the late 1980's.

 

[hugh hargett]

Oh, ok I see what you mean now.