Completed Gas Fire Fighter ... Exotic build

[Scott Schneider]

Just sharing my winter project for 2010 ... a FF rigger with shingled and tunnel ride surfaces.

Powered by one of the new Korean RCMK rear x RZ-254 gassers, build was purpose built for it and to explore the pro's / con's of the ride surface mods that were the buzz a few years ago ... test test test.

All the belly on trailing half was removed on ride surfaces of sponsons so the shingles first to last have a flat profile. Edges painstakingly kept sharp and square all around.

Ran the hull for the first time last Sunday and it ran very light on the water and launched effortlessly with props that did not cavitate excessively.

Boat showed promise but like all new builds will take some trial and error fine tuning to get it on rails and into the mid to upper 70's for oval race duty.

Thanks for looking, your comments are welcome :blink:

Regards,

Scott

 

[TomMoorehouse]

that looks awesome! Ive been thinking of tryng the tiles idea myself. be sure to post what ya think about them.

 

[Blackout]

Looks great, thanks for sharing!

 

[David Meloni]

Nice,,,, I like the all natural look. It also helps in case you want to make changes without having to repaint.

I'm curious to see how this boat is in turns, middle and exit ...

Good job Scott.

 

[Scott Schneider]

Tom,

Boat had it's maiden runs last Sunday, absolutely no bad habits other than it wants low lift props pushing at this point .... time will tell as set up gets tweaked upon.

Hull while on plane had almost zero water slashing from under ride surfaces, a bit while slower, but really clean at speed.

David,

With the running we did do with it @ 4 - 250ml bags, turning prowess was excellent with no tendency to trip. ( I did change sponson shape tho added a non trip chine ) speed scrub coming and going threw the corners was very minimal.

Pretty happy with the hull, it showed great promise and if nothing else it's fun to have something different than everyone else and have built it yourself

 

[bzubee]

Looks pretty nice Scott. Mark Bullard and Doc Turner have been running the Gator back sponson for a few years now. I like your turn fin mount neat way to move it forward and back to find the optimum location for the turn fin, pretty cool.

Tom,

Boat had it's maiden runs last Sunday, absolutely no bad habits other than it wants low lift props pushing at this point .... time will tell as set up gets tweaked upon.

Hull while on plane had almost zero water slashing from under ride surfaces, a bit while slower, but really clean at speed.

David,

With the running we did do with it @ 4 - 250ml bags, turning prowess was excellent with no tendency to trip. ( I did change sponson shape tho added a non trip chine ) speed scrub coming and going threw the corners was very minimal.

Pretty happy with the hull, it showed great promise and if nothing else it's fun to have something different than everyone else and have built it yourself

 

[Terry Keeley]

Nice clean job!

 

[MattHench]

Very nice, sweet sponson design, know what you mean about havin somethin different, get's boring when you see all the same boat's runnin around the course, that's why my jae .12 is stayin in the box or sell it !!!!!!!!!!!

 

[Blackout]

Very nice, sweet sponson design, know what you mean about havin somethin different, get's boring when you see all the same boat's runnin around the course, that's why my jae .12 is stayin in the box or sell it !!!!!!!!!!!

Yup, different is good! That is what this hobby is all about. Or we can just race RTR's, and let the third world factories build our boats.

 

[Tim_Duggan]

Tom,

Boat had it's maiden runs last Sunday, absolutely no bad habits other than it wants low lift props pushing at this point .... time will tell as set up gets tweaked upon.

Very nice build Scott! What was the issue with the higher lift props? Blowing out the rear / hopping / ploughing the fronts,Or Launching?

 

[Scott Schneider]

Tom,

Boat had it's maiden runs last Sunday, absolutely no bad habits other than it wants low lift props pushing at this point .... time will tell as set up gets tweaked upon.

Very nice build Scott! What was the issue with the higher lift props? Blowing out the rear / hopping / ploughing the fronts,Or Launching?

Tim,

Too much hop in general, launching was fine with them and no plowing either ... just hoppy in the straights an bad in the corners. That may change some because strut had a couple degrees negative in it after the fooling around i did finding a depth the hull needed and props liked. Once I fitted one of my highly modified low lift props hull settled right down. With the turn fin originally fitted weight transfer was not right either, so like all boats new some fine tuning and such is in order.

 

[Tim_Duggan]

Hi Scott,

If you don't mind me asking, what is the weight at the strut and the total weight RTR?

I have not played with the FFgas but if it's anything like it's smaller brothers, strut angle should be very low - almost 0 deg with a tub angle at about 1 degree and the bottom of the shaft level with the bottom of the rears or lower.

Again, hats off for an awesome build!

Tim

 

[Scott Schneider]

Hi Scott,

If you don't mind me asking, what is the weight at the strut and the total weight RTR?

I have not played with the FFgas but if it's anything like it's smaller brothers, strut angle should be very low - almost 0 deg with a tub angle at about 1 degree and the bottom of the shaft level with the bottom of the rears or lower.

Again, hats off for an awesome build!

Tim

Tim,

RTR weight came in at @ 13 1/4# .... have not weighed the distribution of front to rear tho.

As stated the first runs were just shake down tests and finding the strut a few degrees negative after the fooling around know for fact that had a huge effect on the hopping boat exhibited. ** The biggest issue that most seem to have questioned is the attributes or sensitivity the fronts will have on AOA .... too the contrary found out right away with high lift props jacking up the back of boat flattening out the AOA to 2* or less to fitting low lift props dropping tail having hull run on the 4* as assembled .... smoothness and a total lack of plowing of the sponsons remained running both way ... pretty **** amazing IMO.

 

[Scott Schneider]

Hi Scott,

If you don't mind me asking, what is the weight at the strut and the total weight RTR?

I have not played with the FFgas but if it's anything like it's smaller brothers, strut angle should be very low - almost 0 deg with a tub angle at about 1 degree and the bottom of the shaft level with the bottom of the rears or lower.

Again, hats off for an awesome build!

Tim

Tim,

RTR weight came in at @ 13 1/4# .... have not weighed the distribution of front to rear tho.

As stated the first runs were just shake down tests and finding the strut a few degrees negative after the fooling around know for fact that had a huge effect on the hopping boat exhibited. ** The biggest issue that most seem to have questioned is the attributes or sensitivity the fronts will have on AOA .... too the contrary found out right away with high lift props jacking up the back of boat flattening out the AOA to 2* or less to fitting low lift props dropping tail having hull run on the 4* as assembled .... smoothness and a total lack of plowing of the sponsons remained running both way ... pretty **** amazing IMO.

Had a few PM's asking about if anything was done to rear sponson ? .... so here ya go ... Yes

 

[Charles Perdue]

Hi Scott,

If you don't mind me asking, what is the weight at the strut and the total weight RTR?

I have not played with the FFgas but if it's anything like it's smaller brothers, strut angle should be very low - almost 0 deg with a tub angle at about 1 degree and the bottom of the shaft level with the bottom of the rears or lower.

Again, hats off for an awesome build!

Tim

Tim,

RTR weight came in at @ 13 1/4# .... have not weighed the distribution of front to rear tho.

As stated the first runs were just shake down tests and finding the strut a few degrees negative after the fooling around know for fact that had a huge effect on the hopping boat exhibited. ** The biggest issue that most seem to have questioned is the attributes or sensitivity the fronts will have on AOA .... too the contrary found out right away with high lift props jacking up the back of boat flattening out the AOA to 2* or less to fitting low lift props dropping tail having hull run on the 4* as assembled .... smoothness and a total lack of plowing of the sponsons remained running both way ... pretty **** amazing IMO.

Scott, what you are describing with the shingled tunnels was exactly what I experienced, they are not sensitive at all and they find their own sweet spot without a lot of adjusting and run VERY clean. There will be some more shingled sponsons running on the left coast this year, SAW and heat racing.

One other thing you might want to do. Undercut the inside edge of the shingles with an about 30* angle. This helps the shingles to come clear from the waters surface a little quicker, track straighter and gives a little bit of extra bite in the corners. Other than that you did very well.

You did a great job applying the info that was discussed on this thread. Very nice build and a very nice boat.

As you learn your new boat you will find that it will be very consistent in most water conditions. That is what wins races.

Good luck with your new toy.

Charles

 

[Scott Schneider]

Hi Scott,

If you don't mind me asking, what is the weight at the strut and the total weight RTR?

I have not played with the FFgas but if it's anything like it's smaller brothers, strut angle should be very low - almost 0 deg with a tub angle at about 1 degree and the bottom of the shaft level with the bottom of the rears or lower.

Again, hats off for an awesome build!

Tim

Tim,

RTR weight came in at @ 13 1/4# .... have not weighed the distribution of front to rear tho.

As stated the first runs were just shake down tests and finding the strut a few degrees negative after the fooling around know for fact that had a huge effect on the hopping boat exhibited. ** The biggest issue that most seem to have questioned is the attributes or sensitivity the fronts will have on AOA .... too the contrary found out right away with high lift props jacking up the back of boat flattening out the AOA to 2* or less to fitting low lift props dropping tail having hull run on the 4* as assembled .... smoothness and a total lack of plowing of the sponsons remained running both way ... pretty **** amazing IMO.

Scott, what you are describing with the shingled tunnels was exactly what I experienced, they are not sensitive at all and they find their own sweet spot without a lot of adjusting and run VERY clean. There will be some more shingled sponsons running on the left coast this year, SAW and heat racing.

One other thing you might want to do. Undercut the inside edge of the shingles with an about 30* angle. This helps the shingles to come clear from the waters surface a little quicker, track straighter and gives a little bit of extra bite in the corners. Other than that you did very well.

You did a great job applying the info that was discussed on this thread. Very nice build and a very nice boat.

As you learn your new boat you will find that it will be very consistent in most water conditions. That is what wins races.

Good luck with your new toy.

Charles

Thanks for the input Charles.

* When you say "Undercut" .... we talking trailing edge of each shingle ? ... or lengthwise down the edge of both sides of the stack ?

 

[Charles Perdue]

Hi Scott,

If you don't mind me asking, what is the weight at the strut and the total weight RTR?

I have not played with the FFgas but if it's anything like it's smaller brothers, strut angle should be very low - almost 0 deg with a tub angle at about 1 degree and the bottom of the shaft level with the bottom of the rears or lower.

Again, hats off for an awesome build!

Tim

Tim,

RTR weight came in at @ 13 1/4# .... have not weighed the distribution of front to rear tho.

As stated the first runs were just shake down tests and finding the strut a few degrees negative after the fooling around know for fact that had a huge effect on the hopping boat exhibited. ** The biggest issue that most seem to have questioned is the attributes or sensitivity the fronts will have on AOA .... too the contrary found out right away with high lift props jacking up the back of boat flattening out the AOA to 2* or less to fitting low lift props dropping tail having hull run on the 4* as assembled .... smoothness and a total lack of plowing of the sponsons remained running both way ... pretty **** amazing IMO.

Scott, what you are describing with the shingled tunnels was exactly what I experienced, they are not sensitive at all and they find their own sweet spot without a lot of adjusting and run VERY clean. There will be some more shingled sponsons running on the left coast this year, SAW and heat racing.

One other thing you might want to do. Undercut the inside edge of the shingles with an about 30* angle. This helps the shingles to come clear from the waters surface a little quicker, track straighter and gives a little bit of extra bite in the corners. Other than that you did very well.

You did a great job applying the info that was discussed on this thread. Very nice build and a very nice boat.

As you learn your new boat you will find that it will be very consistent in most water conditions. That is what wins races.

Good luck with your new toy.

Charles

Thanks for the input Charles.

* When you say "Undercut" .... we talking trailing edge of each shingle ? ... or lengthwise down the edge of both sides of the stack ?

I was suggesting down the inside edge of each stack. It also helps at the trailing edge of each shingle.

An angle of 30* is an all around good back cut or undercut to keep water from following around the edge of the wet surface.

I see that you also did not build any diahedral at all into the sponson bottoms. This is what the shingled tunnels like. Makes for some smooooooooooth running.

Keep us up to date with your testing.

Charles

 

[misshydro]

looks awsom... B)

 

[Scott Schneider]

After another couple hours run time finding prop & strut settings that settle down the hull into race attitude & trim .... the design just ROCKS !!

Spent a bit of time conversing with Jim Wilson at the Gary Johnson Memorial Gran Prix Classic who also just applied the design to his record setting sport 21 hull, we critiqued what each had done right or wrong coming up with further fine tuning ideas to fit each hulls needs.

One thing we both agreed on was the need for ALL edges to be very flat, crisp and sharp !! .... about 15-30* of backcut on shingles trailing edges is highly recommended.

More to follow if something worth mentioning comes to light :blink: