Doubledog

My Feedback: (48)

Ken, come on man... a 5.3 in prop with that engine? What prop on the chart has that pitch ratio?

**EDIT, I'm looking at my prop charts & the only thing I come close to is ABC & Propshops so we're even off the page for this boat as it doesn't run those.**

Even if it was possible, the thing would have MONSTER torque to pull it at those revs. Plus you've got to consider a lot of other things to get a boat that effecient.

ken0276

My Feedback: (2)

Jamie, ABC 2167/3 does but I don't think it's a good prop for mono cause its diam. He can raise the strut until the engine screams on the water but he really needs a good CG for the boat or blow off.

Doubledog

My Feedback: (48)

Ok Ken, you've officially lost me now. We've got to stay on the same sheet of music.

My point was, there isn't much in the way that a 12k engine is going to run 45mph unless its a large prop & extremely efficient setup. Plus @ 5.3 you're talking about extreme pitch which works well for riggers etc.

Share on

**edit again**
I see the 2167 on the prop chart but isn't this a rigger prop? Pretty much useless on a mono?

Grimracer

The Grimracer 67X105/3 is right around 2.6 dia and 4.1" of pitch.

Grim

ken0276

My Feedback: (2)

Jamie, forgot about these 670 or 2716 prop, we might misunderstand each other...the Rio 51's designer was here sometimes, we should ask him what's the best speed for his mono, 45 MPH is not a big number, lots 260s can over reach that, also the guy confirmed that speed by GPS, why didn't you believe him? I had 2 Mid-west missile II gas riggers in the past years, BBmods saw that a lot, the best prop for that rigger was a 6719/3 or V967/3 5.12" prop, Have you seen a 41" cat powered by a stock 260 runs with a 5.55" pitched prop? which I mean every 260 can run a big pitch prop if it in a normal working condition....

Grimracer

Ken0267

Just to clarify for the new guys, our boat (Rio 51) is not Zen powered having said that we are always looking to make more HP… Aha.. The true life of a gear head… isn’t it great!

Our Fuji Engine is a tad off the mark from the Zen in HP but it is still quite good and remember.. its task was to get some RTR action for the masses. It does that quite well.

Also.

I have run The Rio over 45 and its just keeps rocking. I feel the hull is capable of quite a bit more.

Remember..

45MPH at 80db is noting to sneeze at. You can go faster with a different pipe but to us we feel we need to be as responsible as we can about helping racers keep there ponds through quieter model boating.

Also.. for those of you that want to experiment.. You do know (I think I have said it before on here someplace) the exhaust bolt pattern to the Fuji 28 is the same as the Zen.

Enjoy and see ya at the pond

Grim

ken0276

My Feedback: (2)

I knew that Grim, they are pretty similar around 25cc engines for me, the only difference is the HP and RPM. I agree with that, a good tuned pipe especially the steel pipe can make more a couple MPH, I saw some Zenoah type alum or steel pipes on bay and the prices are reasonable.

ken0276

My Feedback: (2)

Jamie, Those are stuff are the hobbies so don't be serious, you might fill up 4 numbers on this then the MPH will pop up.



http://www.props4u.com/prop_chart.htm

martno1fan

Im with Jamie on this to be honest,as you say the fuji isnt a zen and id like to see it do 45 in a mono i really would so i hope they post some video of it.Also to say a pipe has to be loud to produce great power is not true ask Jamie i believe he runs the jeroen pipe ?,also dave marles has very quiet pipes that give great power ask anyone whos run them.Both come well under 85 desables 82 to be exact.
[link]http://www.jeroentune.nl/indexpipeeng.htm[/link]

[link]http://www.prestwich.ndirect.co.uk/gaspipes.htm[/link]

Justaddwata

My Feedback: (3)

For what it is worth I dare say that boat in the video looks to be running in the 40's. I would imagine it capable of such with just a prop change. I have seen bigger boats with stock motors running faster so I no doubt it can be done.

I see the 12000rpm number mentioned - is that a tach reading or is the motor limited? Will it rev beyond that. Sounds like it is running harder than that but my ear is not that well calibrated.

Funny how quickly the interest in this boat has gone from that of a starter boat to one of "how fast will she go".

There was not one of these under my tree (was not much under there at all sadly ).

glennb2006

There was not one of these under my tree (was not much under there at all sadly ).
[/quote]


Probably because there was no more space for any more boats in your house Matt...

Glenn

glennb2006

Hi Ken,

my tuned zen does not like high pitch, so I would question your comment. I run fine pitch, short pipe and high revs and, everyone is a winner...

I am impressed that this RTR is doing 45 MPH as a standard, that is really quite quick.

It is going to be very interesting to see what the final top out speed works out as.


Glenn

ken0276

My Feedback: (2)

Glenn, My 260s on my 41" Cats didn't like high pitch prop either but since a member told me to raise the strut about 5/16", oh man, the Cat was insane right away....but before I did that I had to change my Cat's CG other than the factory recommendation.

Doubledog

My Feedback: (48)

Ken,
No one here is upset but you are extremely hard to follow.

FTR, You said that the boat will run 45mph turning a 5.? pitch prop @ 12k.

I'm only asking -- How is this possible? What engine is going to make the torque to do so at that engine speed?

THAT was my initial point. Please verify this information & how it will work.

This time try not to loose us.


__________________________________________________ _____________________

Next,
I'm not taking any stabs at the Rio. Mike (Grim) says it will run 40+ then OK. My only questions were made about the boat a few threads back.
__________________________________________________ _______________

Exhausts....

Yes, I run JTP's & love them. They're pretty easy to tune, run fast as stink & QUIET. Did I mention they're QUIET?

I've ran almost every quiet version out there except the Prestwich. However, the QUIETEST to my ears & others that I run with is the NEW Hanson system. In my latest build, it didn't work out size wise because. Its pretty large & wouldn't work for its intended application.

One last time for a REMINDER ~~ I'm not knocking the Rio.


Just somehow Ken got off on how a 5.? prop can push a boat to 45+ @ 12k.
Later,
Jamie

ps, no one is pissed off. [8D]

edmkills

Just curious how does the pipe exit the transom does it allow for some movement? I don't think vibration is breaking the weld but rather the torque of the motor twisting the dampners. If the engine can move more than pipe through the transom will allow somethings got to give.

Grimracer

The way the pipe is mounted has nothing to do with the headers breaking..

Thanks for you input..

ROCK ON

Mike

martno1fan

What is the reason Mike have you got to the bottom of it now?.
Mart

ken0276

My Feedback: (2)

Ok Jamie, I might not discuss with you at this point anymore, me and you don't make this BT-28 engine, so the best way to do this is to let the Fuji engine guy to reply this question if possible, if the answer on your side, you'll be the winner, is that OK?

pyro1

SOOOOOOOOOO true

Doubledog

My Feedback: (48)

Once again, you miss the point. Don't get frustrated at me, just stick to the program & quit dogging the question.

Where is this prop a 5.? pitch ratio? Who said its running that size prop? You said with a 5.? pitch ratio it would run 45mph @ 12k. Ok, but the boat does not come with a prop that size.

Where is this prop 5.3 ratio to make it run that fast @ 12k.???

I'm only asking you to show how you get this. Nothing more.

Doubledog

My Feedback: (48)

Btw, I'll always be a winner... (at least that what my wife tells me)[sm=biggrin.gif] God bless that woman.

ken0276

My Feedback: (2)

Hey "Winner", I'm really confused with what you said that between pitch and ratio, I just know the prop's Dim. and pitch, if you take that ratio away, the question will be more simple and easy before continual....

Doubledog

My Feedback: (48)

Ok, I give up. You just can't make posts like that as they might steer newbies the wrong direction.

Chat later on another thread. Btw, I'm taking my boats too & you can't play with them (joke bro', have a good one)

ken0276

My Feedback: (2)

I'm a new too Jamie, I was trying to learn something here as I could, look at those guys, especially the second last one, he has a couple awesome Cats to aims on me... just kidding...let the moderator knows if I'm wrong.





bd323, BlizzWave, brianwhiteboy, CC Racing Engines, Doubledog, firelite_marine, ken0276, malicent, mauian, radman35, skoda450, Tahoe1970, webdr

Believe It

Would have to be a very small diameter prop to spin 12000rpm with 5+ pitch.


and i doubt there are many motors on the market (if any) that would spin any prop thats 65+mm with a 5.0 pitch ratio...as with a 5.0 pitch RATIO, you'd have ALOT of pitch (IE a 6717/3 has 4.48 pitch... the 17 = 1.7 pitch ratio).