Dumas Circus Circus Rossi 90 HELP PLS

[FlogginHarvey]

Okay,

Well, my first ITLwaters post. I will start by saying I am a big RC GAS boat geek but not much (nothing) by way of Nitro. A friend here started a Hydro build 12 or so years go with a Rossi 90 and finally finished it up about two days ago. We ran last night for the first time and needless to say we learned a TON in three hours and still need to learn a TON more!

So, all we had was 10% nitro fuel - hear it needs to be 30% or 40% roughly 3 turns out on the hi needle

no idea what pipe length is

prop looks like a Octura 455 or somewhere close.

When we launched the boat it BARELY went on plane and by the end we were actually able to keep it running enough to circle back to shore! (A HUGE ACCOMPLISHMENT FOR US LAST NIGHT BY THE WAY)

Anyway, if anyone can offer some starting points for everything (fuel type, pipe lenght, needle start setting, prop, strut heighth, etc) we would be VERY appreciative to say the least.

After being around and getting familiar with gas I forgot how frustrating it is to be a total beginner again! VERY HUMBLING...

Thanks for help/suggestions. We obviously need it!!! Oh, is there a way to get a emaili alert on this forum when some one replies to your thread? Jim's does that and it is really helpful?

 

[Ray Sametz]

Rossi 90 with a 455 prop, glad you didn't blow it up. More details??????

 

[Hydro Junkie]

I have to agree, a 455 is not near enough prop. You should be running at least a 460 but more likely between 465 and 475 to start with, so not getting any revs was a good thing.

Something else you need to remember is that the more nitro you run, the more fuel flow you need. Since you were running very low nitro, you may need to close down the needle a bit. If the plug was really wet, you were running too rich

Are you running a pressure fuel system? If not, you may have had a fuel flow issue as well, in this case running lean.

 

[FlogginHarvey]

Wow! Good to know on the X455...I bought it from CMDi a couple years ago at there suggestion when i told them what motor and hull to run it on! Yikes! (for the Prather 46 mono)

No, I am sure he had a pressure line: The is the line tapped into the exhaust to the vent on the fuel tank, yes?

On the needle, we played and played until it actually would stay running the lap...it just wouldn't get up on the pipe and really plane out. Another friend is a drag boat racer and he said it wasn't "blowing the transom" I think I remember.

After running some other Gas RC boats is almost seemed to me that there was too much strut/prop in the water...How far below/above the outside ride-pads should we start with strut depth?

I bought some fuel from Tower today...O'Donnell 40% and a handful of McKoy MC9 plugs. Is that the right "stuff?"

 

[FlogginHarvey]

well...it might be an important detail on the Prather -- it is a submerged drive and NOT a surface drive. I would think I may need a bit smaller prop than a surface drive setup on the same hull/motor???

 

[Hydro Junkie]

If it's running a fully submerged prop, that's half of the problem. Could you post some pictures so we can see what you have to work with and recommend changes accordingly

 

[Glenn Gates]

Wow! Good to know on the X455...I bought it from CMDi a couple years ago at there suggestion when i told them what motor and hull to run it on! Yikes! (for the Prather 46 mono)

No, I am sure he had a pressure line: The is the line tapped into the exhaust to the vent on the fuel tank, yes?

On the needle, we played and played until it actually would stay running the lap...it just wouldn't get up on the pipe and really plane out. Another friend is a drag boat racer and he said it wasn't "blowing the transom" I think I remember.

After running some other Gas RC boats is almost seemed to me that there was too much strut/prop in the water...How far below/above the outside ride-pads should we start with strut depth?

I bought some fuel from Tower today...O'Donnell 40% and a handful of McKoy MC9 plugs. Is that the right "stuff?"

Harvey, X457/3 or x460/3, Strut about 1" from bottom of boat to center of strut- Pipe 11"+ to start. OD 40% and MC9's should work. The strut should set level on a table with the prop,rudder and skid fin hanging off the table edges.

Glenn

 

[FlogginHarvey]

Harvey, X457/3 or x460/3, Strut about 1" from bottom of boat to center of strut- Pipe 11"+ to start. OD 40% and MC9's should work. The strut should set level on a table with the prop,rudder and skid fin hanging off the table edges.

Glenn

tHANKS! I will get some pics (not my boat but belongs to a friend here at the Lake). I will take notes from here and make the changes and se what we come up with1 Thanks guys!!! As I said, we are total Nitro beginners so if there is any other "starting tips" for setup please don't be shy. Again, thanks!!!