sponson shape

[Rigged]

ok i see now. Pretty decent speed with a 275 i supose. I like how your boat looks.

Mine is powered by a Quickdraw 25HT & QD Hotpipe.. same motor/pipe combo in my cat has been 70mph, id hope the rigger will at least be able to match that. Sofar have a 2916/2, 3014/2 and 2716/2 20* to try... ill have to try grabbing a 6719/3 to try on it as well. Hopefully my boom tube clamps show up this week so i can finally get it wet sunday.

 

[Geraghty]

#3.... Don.. it wont trip on that edge..

Tell ya what. Put that on the left sponson of a rigger & then tell me what happens when you throw it hard into a corner at speed. I'll give you a hint, you'll get to know the retrieve boat real well..........

Don my .12 rigger is like #3 on both sides with a stepped bottom. I can turn my rigger so tight it will spin your head and it never trips on the edge. That little overhang keeps the sides of the sponsons from wetting up and creating drag. Maybe it is different for larger boats . But it works great on the light little .12's. hitting near 50mph.

Mark

Mark,

It isn't any different for the larger boats........just keep on doin' what you have been doin'.

Rod

 

[Don Ferrette]

#3.... Don.. it wont trip on that edge..

Tell ya what. Put that on the left sponson of a rigger & then tell me what happens when you throw it hard into a corner at speed. I'll give you a hint, you'll get to know the retrieve boat real well..........

Don my .12 rigger is like #3 on both sides with a stepped bottom. I can turn my rigger so tight it will spin your head and it never trips on the edge. That little overhang keeps the sides of the sponsons from wetting up and creating drag. Maybe it is different for larger boats . But it works great on the light little .12's. hitting near 50mph.

Mark

Mark,

It isn't any different for the larger boats........just keep on doin' what you have been doin'.

Rod

Whatever Rod.

I know what I saw when one guy tried it .... and tried it ..... and tried it. He was no average boater either when he ran with us years back. A very analytical type .... sharp guy who often thought outside the box .... sometimes waaaaay outside the box. ^_^ Many variables can come into play so there's no guarantee what works for one will always work for all ... and vice versa.

 

[AndyBrown]

#3.... Don.. it wont trip on that edge..

Tell ya what. Put that on the left sponson of a rigger & then tell me what happens when you throw it hard into a corner at speed. I'll give you a hint, you'll get to know the retrieve boat real well..........

Don my .12 rigger is like #3 on both sides with a stepped bottom. I can turn my rigger so tight it will spin your head and it never trips on the edge. That little overhang keeps the sides of the sponsons from wetting up and creating drag. Maybe it is different for larger boats . But it works great on the light little .12's. hitting near 50mph.

Mark

Mark,

It isn't any different for the larger boats........just keep on doin' what you have been doin'.

Rod

Whatever Rod.

I know what I saw when one guy tried it .... and tried it ..... and tried it. He was no average boater either when he ran with us years back. A very analytical type .... sharp guy who often thought outside the box .... sometimes waaaaay outside the box. ^_^ Many variables can come into play so there's no guarantee what works for one will always work for all ... and vice versa.

"Many variables can come into play so there's no guarantee what works for one will always work for all ... and vice versa."

That's the reality!

 

[hydro]

Needs opinion: what is the best bottom shape of front sponsons ( rigger, hydro ). I completeted FIRE FIGHTER Gas Rigger and ROCKET Retro Hydro with #1 shape of sponsons. Now is timer to make improvements. Thanks. Boris

Number four is the one to go with, a small step is good but add more chine angle and then back cut the deck some so the profile is not to wide. Sorta like what roadrunner does, By the way they did not invent that .....it's been around for a long time before there were even model riggers. I am very big on lots of chine angle. Those firefighter riggers look ok , but the sponson chine line not enough for my taste, way to square like pushing a block of wood sideways across the waves LOL . Also the chine angle on the rear sponson is some what more important than the front. On the front sponson you have a large angle of attack the give you some leeway on tripping. On the rears typically, that have very little angle of attack , so the whole side profile of the sponson in relation to the water is increased, the result is easier tripping on square shoulder sponsons. You want the boat to have a limited slide in the corners controlled by the turn fin and go thru crazy water & not trip. Lots of chine angle for the most part in conjunction with the turn fin make's that happen.

John

 

[Grimracer]

#3.... Don.. it wont trip on that edge..

Tell ya what. Put that on the left sponson of a rigger & then tell me what happens when you throw it hard into a corner at speed. I'll give you a hint, you'll get to know the retrieve boat real well..........

Don my .12 rigger is like #3 on both sides with a stepped bottom. I can turn my rigger so tight it will spin your head and it never trips on the edge. That little overhang keeps the sides of the sponsons from wetting up and creating drag. Maybe it is different for larger boats . But it works great on the light little .12's. hitting near 50mph.

Mark

Mark,

It isn't any different for the larger boats........just keep on doin' what you have been doin'.

Rod

Whatever Rod.

I know what I saw when one guy tried it .... and tried it ..... and tried it. He was no average boater either when he ran with us years back. A very analytical type .... sharp guy who often thought outside the box .... sometimes waaaaay outside the box. ^_^ Many variables can come into play so there's no guarantee what works for one will always work for all ... and vice versa.

Don.. True enough man.. true enough...

However laws of physics don’t change.

It like Vacuum forming..

There are a few key principles.

Heat, vacuum and draft angle.. and I can STILL FIND 25 ways to screw up a part. There really are no dead set rules to vacuum forming except for the ones listed above.

Manipulating the water is the same.. no dead set standards just how well we work with what we are given – physics.. and for some reason I just can not get it to change to my way of thinking.

Truth is there really is little to no difference between #2 and #3. #2 is just a good way to pull #3 out of a mold. Dang key principles..

ROCK ON.. go with #3..

The spell check thing is still funny tho...

Grim

 

[Preston_Hall]

The prop is PRATHER 275, SIKK-27 with ligted up piston (I remove ~3g from 31g). Boris

Shorten the pipe & put a 6719/3 blade on it.

If he is having problems at low speed then why would he shorten the pipe?

 

[AndyBrown]

All four of those sponson configurations have won many Championships and set many records, past and current.

 

[Grimracer]

very true.. and i suspect there have been others as well...

Grim

 

[Don Ferrette]

The prop is PRATHER 275, SIKK-27 with ligted up piston (I remove ~3g from 31g). Boris

Shorten the pipe & put a 6719/3 blade on it.

If he is having problems at low speed then why would he shorten the pipe?

He's only doing 50mph and pipe looks rather long. One thing we have found is having the pipe wrong on the gassers seems to hurt both sides of the powerband. Also that Prather 275 is not a good choice for a rigger, the smaller diameter & higher pitch of the 6719 will work better at low & high speeds. Been there, done that .............

 

[Rigged]

one issue i see though is, the 27cc CY's are not RPM monsters, they are more so torque motors. May not be able to pull a 6719/3 into the 17000+ range needed to go "fast"...

 

[Boris Mazor]

The prop is PRATHER 275, SIKK-27 with ligted up piston (I remove ~3g from 31g). Boris

Shorten the pipe & put a 6719/3 blade on it.

If he is having problems at low speed then why would he shorten the pipe?

He's only doing 50mph and pipe looks rather long. One thing we have found is having the pipe wrong on the gassers seems to hurt both sides of the powerband. Also that Prather 275 is not a good choice for a rigger, the smaller diameter & higher pitch of the 6719 will work better at low & high speeds. Been there, done that .............

Hi, Don! How long pipe have to be? I still can short it ~1 1/4". I tryed to use 6719 prop, but ... have no proper launch. Will do this on weekend.

 

[Don Ferrette]

The prop is PRATHER 275, SIKK-27 with ligted up piston (I remove ~3g from 31g). Boris

Shorten the pipe & put a 6719/3 blade on it.

If he is having problems at low speed then why would he shorten the pipe?

He's only doing 50mph and pipe looks rather long. One thing we have found is having the pipe wrong on the gassers seems to hurt both sides of the powerband. Also that Prather 275 is not a good choice for a rigger, the smaller diameter & higher pitch of the 6719 will work better at low & high speeds. Been there, done that .............

Hi, Don! How long pipe have to be? I still can short it ~1 1/4". I tryed to use 6719 prop, but ... have no proper launch. Will do this on weekend.

Let me check where my CY (sikk) is set at later this evening. That pic it doesn't look as long as the earlier overhead shot you posted. Do you have a 6717/3 to try? A 6518 pitched is another good one. When you say no proper launch what do you mean?

 

[Rigged]

ive never used the Cooper pipe, but if my eyes are focusing correctly looks like the pipe is at 9-1/2" to the first weld, 10" to the center of the band.... thats seems very very short....

Don what pitch 6717/3 have you used? I have a backcut 410 that was done for my cat... not sure that'd be enough pitch for a rigger?

 

[Joe_Knesek]

Jon Staudacher's latest 2.5 Liter Modified design pictured below uses overhang. I can tell you first hand the boat handles well & is plenty fast.

 

[Don Ferrette]

ive never used the Cooper pipe, but if my eyes are focusing correctly looks like the pipe is at 9-1/2" to the first weld, 10" to the center of the band.... thats seems very very short....

Don what pitch 6717/3 have you used? I have a backcut 410 that was done for my cat... not sure that'd be enough pitch for a rigger?

You're right, the first posted pic, the overhead shot, made it look longer. My CY pipe length is 10" from center of port to first weld.

None of the props on the rigger were back cut & pitch is higher.

 

[Rigged]

ive never used the Cooper pipe, but if my eyes are focusing correctly looks like the pipe is at 9-1/2" to the first weld, 10" to the center of the band.... thats seems very very short....

Don what pitch 6717/3 have you used? I have a backcut 410 that was done for my cat... not sure that'd be enough pitch for a rigger?

You're right, the first posted pic, the overhead shot, made it look longer. My CY pipe length is 10" from center of port to first weld.

None of the props on the rigger were back cut & pitch is higher.

Come on now... need a little more info then that lol. What kind of pitch on the 6717/3? stock is 448... did you run stock? Dont make me come take that oil back

 

[Don Ferrette]

ive never used the Cooper pipe, but if my eyes are focusing correctly looks like the pipe is at 9-1/2" to the first weld, 10" to the center of the band.... thats seems very very short....

Don what pitch 6717/3 have you used? I have a backcut 410 that was done for my cat... not sure that'd be enough pitch for a rigger?

You're right, the first posted pic, the overhead shot, made it look longer. My CY pipe length is 10" from center of port to first weld.

None of the props on the rigger were back cut & pitch is higher.

Come on now... need a little more info then that lol. What kind of pitch on the 6717/3? stock is 448... did you run stock? Dont make me come take that oil back

Not totally sure to be honest and we're now playing with pitched up 6518/3's, also very fast.

 

[Grimracer]

Joe,

Great looking 2.5s..

grim

 

[Darin Jordan]

Joe,
Great looking 2.5s..

grim

Hmmmmm.... A new generation of Mr. Bud?? Looks like I may have an inspiration for getting to work on the next gen of my HydroSport 28...