1/8 SCALE PROPELLER ALIGNMENT

[mark couty]

Should the tip of the propeller blade be even with the back of the transom ? Not sure what distance to use. I think I read somewhere here that the front of the prop hub should be even with the transom or one drive dog length past the transom. I know someone has an answer for this. Thanks.

 

[Hydro Junkie]

It depends on which rule book you're using. According to the R/C Unlimiteds rulebook, the prop hub must be partially under the hull unless the full sized boat extends further aft. Acording to the NAMBA rulebook, the drive dog may extend one drive dog length beyond the transom while the IMPBA rulebook says the drive dog must be under the hull unless the full sized boat extended further aft. In this case, you need to look at what rules are used in your area and build to meet those rules.

 

[mark couty]

Thanks for the heads up HJ, my club and district race under NAMBA rules, so I will go by that.

 

[Dasboatman]

Mark,

I think you may want to reconsider the 'one drive dog length aft of transon per NAMBA Rule Book (available on-line) and position the drive dog to comply with what I believe ( Maybe there will be a current Rule Book on-line or available from IMPBA soon) the IMPBA current rule is:

"The drive dog must not extend beyond the transom unless the prototype's strut and/or drive dog did. Photo documentation may be requested for proof by race CD or district scale director."

Being that I too am in District 5/7 area, and have only seen Scale boats race twice in the 8 years I have lived in Houston - first time was here at the Lone Star MBC pond while they were still an IMPBA Club, second time was at the Reserve, LA NAMBA Nationals last summer.

If you place the drive dog per IMPBA specifications, the boat will be legal to run under IMPBA and NAMBA Sanctions, without having to reposition the prop. My Oberto is set up this way, my Executone will be set up so it's only NAMBA Sanction legal. Most Districts around Texas/ Louisiana are IMPBA - - you do the math. CHEERS !!! Bob

 

[mark couty]

Good advice to consider, what effect does the different drive dog / propeller distance at the transom have on the boat ?

 

[Hydro Junkie]

The biggest effect is that it makes the boat act like it's longer than it really is, thus changing the ride characteristics of the boat. I'm sure others will have other things to add to this as well.