Rigger prop depth

[jstolz]

I am new to riggers. I am building a Climate Blizzard. I would lile to get an idea of where the prop centerline should be in relationship to the tub bottom.

 

[crowebar]

I am new to riggers.  I am building a Climate Blizzard.  I would lile to get an idea of where the prop centerline should be in relationship to the tub bottom.

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I don't know where the "sweet spot" would be for this boat, but here is a brief explanation I did a while back that might help you get the concept.

Remember, it's not just depth, but angle too! Depth controls the angle of attack on the sponsons, angle contols the back of the boat. Too much angle and the tail will hop, too little angle and the boat will ride on the transom, not the prop like it should (that means slow).

Good luck,

Dick

 

[Paul Pachmayer]

Hi Dick,

too little angle and the boat will ride on the transom, not the prop like it should (that means slow).

I don't know if I would agree with that. Not saying that having some angle on the strut is a bad thing but for me I wouldn't be satisfied with a hydro that needed angle to keep the transom up. On all my hydros (sport and rigger) I run flat struts and let the prop/CG do the work, guess that's why I like the 17 and P series props.

Paul.

 

[crowebar]

Hi Dick,

too little angle and the boat will ride on the transom, not the prop like it should (that means slow).

I don't know if I would agree with that. Not saying that having some angle on the strut is a bad thing but for me I wouldn't be satisfied with a hydro that needed angle to keep the transom up. On all my hydros (sport and rigger) I run flat struts and let the prop/CG do the work, guess that's why I like the 17 and P series props.

Paul.

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I think you are reading more into this then is meant Paul. The key is to run your boat like a hydroplane and use whatever you have at your disposal to do so: CG, Prop lift, Rudder angle, strut depth and angle.

If you are really hung up on getting your strut as flat as possible you may be sacrificing a good setup to do so.

My N2 Hydro runs best with a non lifting prop. This setup is not the fastest in a straight line, but it is all the way around the course. To use my little x632 I need to have a little angle in the strut so that I don't drag the tail of my boat around the lake and get my tail kicked. I could move my CG farther forward, but then the boat becomes a little unpredictable in the corners and can hop a little as well. I can kick my rudder out a little more, but again, I sacrifice cornering. I try and optimize each variable for the best overall performance.

When you can master CG, Prop lift, Rudder angle, strut angle you'll be ahead of the rest, assuming you have the rest of your act together (motors, batteries, etc). Each has their own important role to play. Ignore one of them and you'll get to follow me around the lake!

See you soon!

Dick

 

[RvE]

If you are running the Blizzard with the rear sponsons on, the stuffing tube centreline is supposed to be at the same depth as the bottom of the sponson.

Without the rear sponsons it can go a bit shallower.

I run with the sponsons and my stuffing tube CL is 3/4" from tub bottom. I run a bit of an angle since I am using X series props.

RvE

 

[Jeff Shriver]

Good post.

Is the strut depth (angle of attack) as important to riggers as it is to sport hydros? Sport hydros pack much more air under them, so too shallow of a strut will cause blowovers. But riggers with their narrow tubs I don't think will pack air in oval racing. I do play with play with strut angle if I change between a X632 and a 1732 to make sure the transom stays up.

 

[Paul Pachmayer]

Hi Dick,

I think you are reading more into this then is meant Paul.

Not really, just that there's more than one way to skin the cat. Take my SAW boats for example, my LSH boat was set up just as it would have been for oval racing, the only real difference was the CG moved back a tick to lossen it up a tick. My O-Sport had the strut set about an 1/8th deeper than I normally would run it in oval trim, but, they both ran flat.

I don't know if you had a chance to run my rigger yet but try the boat with a 6S and a 1732 then try the 632. Push the batteries (6 cell) as far forward as they'll go. That boat has run under 60 many times, even with the owie on the sponson. Not saying it's as fast as your boat butit's no slouch, lol.

Paul.

 

[crowebar]

Paul,

Why do I get the feeling you are arguing with me for the sake of argument?

When I said you were reading more into my statement then was meant. Your reply is Not really?

Then you follow up with "there's more than one way to skin the cat." Did you stop reading after my first comment? Or did I leave something out when I said: "The key is to run your boat like a hydroplane and use whatever you have at your disposal to do so: CG, Prop lift, Rudder angle, strut depth and angle." Maybe I should have just said there is more then one way to skin a cat, but I thought for the benefit of the readers on this forum I'd try to be a little descriptive!

I saw your boat run at the SAW's and I wouldn't have messed with the strut either, mine was too deep though and needed to be shallowed up until the boat floated. I only had enough angle in the strut so that it was parallel at prop riding depth. Ever think about that one?

I'll be happy to debate you till the cows come home on the merits of setting up a hydroplane. The truth is there would be no debate because you set your boats up using the same concepts as I do weather you want to believe it or not.

We're good friends Paul but two things will get me worked up. Saying bad things about my family and telling me I'm out to lunch on Hydro Setup......well, them's fightin words!!!!!

Have a good weekend,

Dick

 

[Paul Pachmayer]

Hi Dick,

Why do I get the feeling you are arguing with me for the sake of argument?When I said you were reading more into my statement then was meant. Your reply is Not really?

Then you follow up with "there's more than one way to skin the cat." Did you stop reading after my first comment?

LMAO!!!!! When I said not really I was agreeing with you, not arguing. I did say that the setup I mentioned was my prefered way of doing things, I also mentioned my prop choices which aren't readily used by the masses.

telling me I'm out to lunch on Hydro Setup

That is something I would NEVER do, if it sounded that way it wasn't meant too. The only reason I put up an "arguement" (lol) was when I read your first post it sounds like putting angle in the prop is the way to go. I was just adding my .02 which put me in the red. :lol:

Your the man Dick, come the NATs I hope to at least stay close to you on the water. I don't kid myself in the pecking order.

Paul.

 

[crowebar]

Thanks Paul,

I did misread read you, I kept thinking to myself, what's he talking about? He does the same things I do?

I was trying to save a little time and re-used a graphic I had made for a slightly different subject hoping it would work on this post too. Although I might be able to add a naked cat to the graphic!

Did you get the New Boat Modeler yet? My Dad got his and told me they talked about our LSH battle!

Thanks!

Dick

 

[Paul Pachmayer]

Hi Dick,

Did you get the New Boat Modeler yet? My Dad got his and told me they talked about our LSH battle!

No, I'll have to pick one up. I don't have a subsciption so I guess it's off to the LHS. I'm still kicking myself for not trying to up my original record early on, oh well, live and learn. I really wish I would have figured out that speedo problem in O-Sport, by he time I did my batts where dead.

This year should be a real battle though huh.

Paul.

 

[crowebar]

Hi Dick,

Did you get the New Boat Modeler yet? My Dad got his and told me they talked about our LSH battle!

No, I'll have to pick one up. I don't have a subsciption so I guess it's off to the LHS. I'm still kicking myself for not trying to up my original record early on....

Paul.

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Oh ya, and then I would have gone out again and........

I still think the O sport was the real dissapointment. It's one of the Few Sport boats I've seen that can handle the speed! Next year right?

Dick