1/8 Hydro prop shaft position

[Jeremy Bodley]

Hi all. Recently purchased a 1/8 scale hydro looking to go over it all and make sure it is setup right.

The prop shaft angle was the first thing I noticed. It is kinked off to the side, seeing the hull is not symmetrical. Just looking for some advice if this is the correct position for this hull or if the prop shaft should be dead straight (not kinked off) and effectively a little off the centre line.

Any thoughts appreciated

 

[Ray Sametz]

My is also offset, it actually centers the prop between the front sponsons. My is a Moceri hull, what is yours. You need to run it and see what happens.

 

[brad nichols]

It depends on the builder. Some set it up with offset motor and drive line, some motor on centre and drive line offset, etc..... There is no right or wrong method as long as the boat runs great. There are lots of different ideas.

Brad

 

[Jeremy Bodley]

No worries. I'll give it a run and see what it's like

I wouldnt mind it being straight. To get that I would either have to move the motor over 1cm or so, and the shaft through the hull. Or have the shaft straight and not centred moving the leg (would prefer to do this). Are either of those mentioned normal? Or no way of knowing but to try haha

cheers

 

[Brandon White]

Mine is pretty straight. Looks about the same style Hull. Mine is from Roger Newton plans. Can you show pictures of the top side for that. Looks like a Winston Eagle.

 

[Mark Anderson]

I would center the strut with the engine. Have not seen a problem with the strut offset to the left of the hull. That bent stuffing box would make me crazy. Probably doesn't matter, but would bug me. If it looks wrong, it probably is.
But as said, run it and see.

 

[Jeremy Bodley]

I would rather move the strut over and have the stuffing tube straight, with the prop offset from the centre but unsure if that's an issue. Mixed feedback. Yeah bugs me looking at it haha. I shall give it a run and see how it goes. Looked like it went well in videos.

 

[Green Meany]

I know it may be stating the obvious but it was done that way because of the center section offset to try to keep the prop on the center line of the hull. My (8808 ultra bold u8) center section is offset to the left as per full-size (original owner built that way). My whole driveline has a kink in it too motor and all I think the strut is still square with the back of the boat l will have look as some use to offset the angle of the prop to them to run straight

 

[Green Meany]

if you measure total width of the tunnel at transom devide by 2 that will be where the strut is . the line you drew was center of center section ( which is offset) which is not the centerline of the hull. I know it looks weird if the center section is offset it is hard to mount the motor on centerline of the hull so this is compromise to get the prop/strut position where it should be

 

[Hydro Junkie]

Has anyone considered looking at a full sized boat? I'll be going to the HARM for an R/C Hydroplane show next weekend and, since the 80-85 Bud is "normally" kept there, I'll take a look and see if it's offset to the left or not, considering it is the boat with the most offset engine bay in the unlimited fleet

 

[Green Meany]

fullsize offset should be left side to keep the left sponson down and the turnfin in the water in the turns .remember we run clockwise and fullsize run counter clockwise. we are allowed to mirror full size offset .what i am unclear about is if fullsize has offset that scale has to have offset or if it is ok to put centre section right down the centerline of the hull

 

[Samuel Hagan JR]

I offset mine 1/4” to the left of center of hull. And Angle the Strut 1 degree to the left sponson. Works great.

 

[Don Ferrette]

I have always centered the strut at the rear and used soft S bend on the stuffing tube to align with offset engine wells. The S bend will not hurt anything and actually will control cable whip, something Ed Hughey proved years ago.

 

[Jeremy Bodley]

if you measure total width of the tunnel at transom devide by 2 that will be where the strut is . the line you drew was center of center section ( which is offset) which is not the centerline of the hull. I know it looks weird if the center section is offset it is hard to mount the motor on centerline of the hull so this is compromise to get the prop/strut position where it should be

It's not quite centred to be honest, anyway I'll give it a run and then make an assessment. Sounds like the bent tube is right. But may need to tweak it a little. Cheers for the help fellas. Any photos of other setups would be great

 

[Mikemalloy]

I offset mine 1/4” to the left of center of hull. And Angle the Strut 1 degree to the left sponson. Works great.

I agree with Sam, I use this same set up on all my boats and no issues

 

[Hydro Junkie]

I just got home from the HARM and, even though I didn't actually do any measuring, I did find out some interesting things:
1) The 1980 Budweiser's prop shaft is actually centered in the boat, running through a gearbox that moves the shaft back to the center of the boat from the highly offset engine location
2) The 1973 Pay'N Pak shaft is centered as well, which is to be expected, considering the engine is mounted on the centerline
3) Both boats have their shafts ANGLED a few degrees from straight down the center, one each direction. I did take pictures of both that I will be posting within the next few days

 

[Samuel Hagan JR]

Regardless of what the real boats have, there is no rule in IMPBA against it.

 

[Hydro Junkie]

I agree. Funny part is, if it weren't for this thread, I wouldn't have noticed the shafts being slightly angled

 

[BobGutsell]

I built my 88 Oh Boy Oberto with a kinked shaft like that, it runs great.