FF12 Complete and at WOT

[Eric Perez]

This is my much anticipated Firefighter 12 Rigger.

It's going to run with MACS 2.5 pipe and Traxxas TRX 2.5 Engine, lightened Octura mount, spedmaster .21 hydro harware and a box full of props!

Just have a few details that need to be address:

Pipe mount

Temporary Cowl

on/off switch

antenna

attach rear shoes

fuel tank

turnfin

... and throw it in the water B)

Here are some pics

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[TomMoorehouse]

looking good eric!

 

[longballlumber]

Eric,

Is that a TRX 2.5 with the traxxas watercooling head?

 

[Eric Perez]

Eric,
Is that a TRX 2.5 with the traxxas watercooling head?

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Yes, that's the marine water cooled head. What's different on this engine is that I used the TRX 2.5 version with the threaded crankshaft. It comes with a long 5mm threaded-insert (25mm grub-screw) and a short one. This "transforms" the engine to the old airplane length crank SPEC and makes it compatible with off-the-shelf 5mm octura flex-hex hardware. I'm running an OS flywheel with an ofna prop-washer (Fit's inside the flywheel and keeps everything tight and slip-free)

Engine-side hardware is a little limited at the moment with small-block powerplants. You almost have to piece it together from stuff you find in your parts bin. A lot of the hot Italian power plants are coming in pilot shaft only configurations. I wonder how the folks are using belt starters on these ???

 

[anthony_marquart]

Eric

Your FF makes mine look like a tank. GREAT work. That's alot of metal on the back of that boat. I've heard that that engine tends to run hot. Some say they don't seal well and are sucking air from somewhere, making then run lean.

Just a word from the grape vine I guess but you might watch it closely, espcially the way we run our engines.

 

[4 play racing]

Eric, I have a question on what size flex shaft and prop shaft you are using....I am building a 30" fiberglass mono around the same TRX 2.5 engine, but have still been trying to determine the best drive setup. I had installed several 2.5's into Nitro Vee's and the engine was much more power than the hull could handle. I'm thinking that with a fiberglass hull and flex shaft versus the solid shaft that the NV uses, I can get it to work. Any ideas?

 

[Ron Olson]

Anthony, the old Traxxas engines used an open cage front bearing that used to suck in a lot of air, throwing the fuel mixture off. If they still have them, I'd replace it with a sealed bearing.

Traxxas has recently come out with a marine version of their motor with a changable threaded shaft on them so you can go short, long or SG style. The downside is it looks like they're still using the slide carb, usable but more linkage hassle.

 

[Eric Perez]

Eric, I have a question on what size flex shaft and prop shaft you are using....I am building a 30" fiberglass mono around the same TRX 2.5 engine, but have still been trying to determine the best drive setup.  I had installed several 2.5's into Nitro Vee's and the engine was much more power than the hull could handle.  I'm thinking that with a fiberglass hull and flex shaft versus the solid shaft that the NV uses, I can get it to work.  Any ideas?

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If the hull is light and you are running surface drive then .130 or .150 flex cable with a 3/16 stub should work well. I run the TRX 2.5 with an octura X438 with rounded corners and a long pipe on a 24" cat with good results. Some folks are turning some monster props with small block engines with success, I think smaller props that turn faster go faster. Look at the speeds that the electics are achieving with small props

Me, personally -The best results with the TRX2.5 have been with 3/16 props that have been cut back and diamter reduced to fall in the 35-36mm range. The RPM's go up and so does the speed...

Octura released a new small diameter X-Series prop the Y536 that has less blade area than a 1/8 35mm prop but mounts to a 3/16 shaft. I would start there and prop up as the model allows.

To run the engine from a T-maxx 2.5 with pull-start or ez-start 2 configuration I just use a T-maxx fly-wheel and use a smooth bore Octura .130 / 5mm flex-hex. I cut a small notch on the pilot shaft of the engine and install the assembly with red-loctite. I have never had any reliability problems with this setup.

There are a few members with .12 monos, I suggest you check some of their setups.

Hope this helps

 

[Eric Perez]

Got some work done on the hull.

I really like the way the front cowl looks. Sort of reminds me a bit of the old Mike P .12 mini-SG rigger from a couple of years ago.

https://www.intlwaters.com/gallery/displayimage.php?&pos=-700

Let's see if this works...

 

[Don Templeton]

Got some work done on the hull.
I really like the way the front cowl looks. Sort of reminds me a bit of the old Mike P .12 mini-SG rigger from a couple of years ago.

https://www.intlwaters.com/gallery/displayimage.php?&pos=-700

Let's see if this works...

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"Yup" I think that was the first .12 rigger I ever saw. We were all talking about building them, Tom was working on some plans and all of a sudden up comes Mike with a picture on his. :huh:

Anyway, that's a super job on your FF.

Don

 

[Eric Perez]

Got some work done on the hull.
I really like the way the front cowl looks. Sort of reminds me a bit of the old Mike P .12 mini-SG rigger from a couple of years ago.

https://www.intlwaters.com/gallery/displayimage.php?&pos=-700

Let's see if this works...

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"Yup" I think that was the first .12 rigger I ever saw. We were all talking about building them, Tom was working on some plans and all of a sudden up comes Mike with a picture on his. :huh:

Anyway, that's a super job on your FF.

Don

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Yes and Mikes rigger ran with a 35mm 1/8 bore propeller... How things have changed...

 

[Eric Perez]

Fire Fighter 12

Well I finally got my FF12 wet this weekend. Here is a play-by-play. Keep in mind that it’s normal to have growing pains with a new boat. This time it was not any different…

I first got the boat to the pond on Saturday. Had a cut-down S215 with a short Macs 2.5 airplane pipe, strut set level and at the same depth as the front sponsons.

I tried launching the boat about 6 times. It would go in almost want to get on plain and just die… I would open up the high-speed needle a little for the next attempt.

I pulled the pipe out a little, moved the strut up a bit and richened her up again I crossed my fingers and launched again. This time the hull popped in plane I turned a big circle and it appeared like I did not have enough rudder throw to make the turn so I shut the engine down near the weeds and got the boat back on the stand.

A quick rudder arm adjustment and I was back on track. The launch was still very difficult but I finally nailed it and it took of. Did a lap and a half and it died again. Well I called it a day. I ran out of time and headed back to the house. I knew the boat worked and all I needed was a little TLC with the engine/prop/pipe combination. That little burst of speed had me hooked.

On Sunday I was up and running again (Yea, I don’t give up!!!) I installed a longer MACS 2.5 airplane pipe and put a new high-speed needle on the carb (On Saturday I was running it so open that the needle fell off…)

The engine seemed to like the longer pipe and I was able to spend some quality trigger time on the pond. The water was a little choppy and it was quite windy. This was the perfect primer for race-water if I ever saw it. Still I struggled to find the right needle setting. It seemed to do a lap and just quit on me. I checked the plug and there was no sign of overheating, changed the plug and went back to the grind.

This time I ran a coupe of good laps and the engine died again… Got the boat back to shore and the high-speed needle was missing again… This is an engine that I got used at the LHS for close to nothing –maybe it’s just too tired. I will troubleshoot the fuel system to make sure there are no leaks, same with the engine. If that does not work I will refresh the engine with a new piston and sleeve.

Still I got a couple of good laps with the boat going into a nice head wind on choppy water and the FF12 was smoking down the straight a way. The boat had a very good composure it never got out of shape even though I was running it hard. I liked the way it handled and I know that once I get things sorted out with the power plant that it will be a great heat-race boat. Sort of wish I had finished this boat in time to enter it at the Fort Worth race this year I would have walked away with some extra wood!

I did notice that even in “wild” water the boat was running quite flat, I think that glass water would probably not be the boats best element. I bet the boat would probably run quite wet on the smooth stuff. I think with the adjustability of the spoons that this could be overcome in part with dropping the spoons down and playing with the prop-angle. This is a race boat meant to be run on race-water, which is almost never flat, so I guess that the boats has been design with rough-water conditions in mind.

I remember a couple of years ago I designed a small electric cat that tended to run wet on smooth water. I could run that thing on extra choppy water and it just went through the rough stuff like it wasn’t even there. It’s hard to design a boat that will run well in all water conditions.

 

[Watercadet]

Eric- that is almost the exact way my first outtings went as well. Out and die. Adjust things. Out one lap stall. Frusterating huh? I have a few great runs yesterday though. I think the motor still needed a little more run in on mine. I think is dragging it's butt arround the course though. Even with a little negative strut (1.5) it wouldn't get dry. I was running a stock 215; it still won't turn a v937/3. :unsure: My day ended with a barrel roll caused by a cross wake. I didn't get off it in time and the crash made the flex hex rip off the end of the crank.

Adam

 

[Don Templeton]

Eric:

Open up the low speed adjustment a bunch. I'm no expert but I had the same problems that you are having the first time out. It would run like a bat out of hell for a lap or so and then sag and die. Then it would act like it was going to go and shut down. The high speed needle didn't have any effect. Preston Hall told me that these motors need a bunch of fuel and to cut off the low speed needle. I didn't cut it but I backed it out as much as I could and I've never had that problem again. Also the high speed needle is now very sensitive.

Don

 

[ClayGlover]

Hmmm, I'm guessing it's the motor/carb is the culprit doods, but you've run them TRX's before with success correct Eric? :huh:

Nothing for nothing, but since you are reviewing TM's boat here on IW, I'll give a quick review too from my side of the fence.

Firefighter 12

Pros- Simple construction, detailed instructions, great support, very easy setup.

First run with an off-the-shelf $150 Mugen MT12 3 port "touring car" motor and Mac 2.5cc pipe. Octura V937 prop. Just set it up like the instructions say to.

Fueled up (55% nitro because that's what I had handy, and the needle was not finicky with high nitro). Started engine with low speed needle all the way out. Dialed main needle to a fairly rich setting. Walked to the lake, tossed the boat in, and had a blast for several tankfulls on its' first outing.

Easy and forgiving boat to setup and run in my experience. Maybe I just got lucky.

Cons- None I can see

These little water rockets are a great way to get into outrigger hydros on a budget. Tom Moorehouse's firefighter .12 is a h00t. B)

 

[Eric Perez]

Hmmm,  I'm guessing it's the motor/carb is the culprit doods, but you've run them TRX's before with success correct Eric?   :huh:

Nothing for nothing, but since you are reviewing TM's boat here on IW, I'll give a quick review too from my side of the fence.    

Firefighter 12 

Pros-  Simple construction, detailed instructions, great support, very easy setup.

First run with an off-the-shelf $150 Mugen MT12 3 port "touring car" motor and Mac 2.5cc pipe. Octura V937 prop.  Just set it up like the instructions say to.

Fueled up (55% nitro because that's what I had handy, and the needle was not finicky with high nitro).  Started engine with low speed needle all the way out.  Dialed main needle to a fairly rich setting.  Walked to the lake, tossed the boat in, and had a blast for several tankfulls on its' first outing.

Easy and forgiving boat to setup and run in my experience.  Maybe I just got lucky.      

Cons-  None I can see

These little water rockets are a great way to get into outrigger hydros on a budget.  Tom Moorehouse's firefighter .12 is a h00t.   B)

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I've run this engine on my last rigger and ran okay, spun all types of props with it 1640, V937, X438, S215 and 1740. I had similar leaning out problems at first but I traced it to a loose tank fitting. I'm hopping that this is the case this time around. I have a couple of gallons on my other TRX 2.5 that I bought new and installed on my cat and it works like a timex watch, heck I start it with the pull start without much problems.

I've sacrificed a low-speed needle to the dremel gods... just to see if I get a bit more reponse from tuning the high-speed needle. I will report an update on my next run. I also added a piece of fuel tubing over the high-speed needle (This is my last one <_<

Over and out. Hey my problems where with the carb/engine/prop/pipe not the boat. I don't want to appear as if I'm giving Tom a black eye h34r:

Quick note: My boat is actually the wide version of the hull. Mine comes up to 3.75" at the tub. I think some of the newer versions are coming out to be 3.5" but I'm not sure . Clay how wide is your tub?

And I quote myself :

Still I got a couple of good laps with the boat going into a nice head wind on choppy water and the FF12 was smoking down the straight a way. The boat had a very good composure it never got out of shape even though I was running it hard. I liked the way it handled and I know that once I get things sorted out with the power plant that it will be a great heat-race boat. Sort of wish I had finished this boat in time to enter it at the Fort Worth race this year I would have walked away with some extra wood!

End of my own quote B)

 

[ernest2]

hi eric,

i have a few questions. i am thinking (and saving ) of buying a strut, the one your using is speedmaster, is this strut complete? i will be using it in a .21 engine. what else do i need to complete the strut setup and what size would my stuffing tube be?

thanks!

ernest

 

[Eric Perez]

hi eric,i have a few questions. i am thinking (and saving ) of buying a strut, the one your using is speedmaster, is this strut complete? i will be using it in a .21 engine. what else do i need to complete the strut setup and what size would my stuffing tube be?

thanks!

ernest

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Yes, the speed master .21/.45 strut is "complete" - but you will need (2) 3/16 led-teflon sleeve bearings if that's what you like using; or you can use a piece of brass tubing with one side flared or solder a small piece of the next size up. I have tried both and like the brass tube cause it's cheaper.

I'm not sure about the diameter of the tube that goes in. I will check when I get home -I'm sure someone will chip in before that. All I know is that it's a tight fit I had to heat the strut with a torch and sanded the tube down a little to help it go in.

Yep, 1/4 brass tube is what you need. I'm not sure what the stuffing tube diameter is for 3/16 cable. I know that you want to run a solid connection from the strut to the stuffing tube. Design the system so if you need to adjust the strut the tube side on the stuffing box is the one that moves back and forth. This will make the installation stronger, yet allow for adjustability of the system.

 

[anthony_marquart]

I finally got my FF.12 out last night. I'm runing the E.P. special sponsons with mine now. Usually I only have the opportunuty to run the boat in the evening when the water here is very smooth. No exception last night. This was my first run with Eric's Sponsons.

I'm now running a rear exhaust Picco .15, macs 2.5 pipe and a variety of props. The hull is now running with a greater AOA on the sponsons and the tub. The sponsons definitley ran lighter on the water. In fact, going down the straight at full speed the left sponson was only occasionally touching the water. The right sponson was deeper of course do to the fin. I need to adjust the angle on the fin to lighten it up some. I'm running Grims .12 fin with this set up and it is perfect for this boat. In the turns I could see where the fin was lifting just a little and gripping the water with just the hooked part of the fin. I noticed what seemed like a reduction in drag through the turns. Eric's sponsons are also much lighter than the orignial FF.12 spoons.

The boat was noticibly faster with Erics Sponsons. Eric's sponsons are just a little wider and the booms place them out a bit further. The rounded tops also create lift and keep the boat light. I do think I will have to decrease the sponson AOA for race water. I could see the boat getting real light at the speeds it's now running.

Eric, you're design is a great success in my book. I don't see a need to go back to the original spoons unless I have some crazy problem int he future. Right now they appear to be a good improvement.

I also had an unexpected discovery with props. I have a few different 215's. Some bar cut with tounge cut back,...etc... I have one that I cut the tounge back just a little and left the tips where they were, except that I sharpend and thinned those tips till the prop was actually dangerous to handle. This prop was the fastest one last night. It put up an odd rooster tail, lifted the rear of the boat a bit more than the others and REALLY flew.... I was surprised...

I'll post pics of the boat with Erics sponsons at lunch.

Anthony Marquart

 

[Watercadet]

I'm not sure about the diameter of the tube that goes in. I will check when I get home -I'm sure someone will chip in before that. All I know is that it's a tight fit I had to heat the strut with a torch and sanded the tube down a little to help it go in.

1/4"

Adam