74 inch Mono with 4-cylinder engine
 

pics of internals and vid-links will follow when finished.......

some data:
hull 1850 x 480mm
weight: nearby 30kg (about 60lbs)
self designed 4-cylinder named RAT HOUSE (see: www.matho-powertrain.de ) with approx 22hp
self designed splitter gearbox with overdrive
4 pipes
electronic ignition www.power-spark.de
3 stainless steel tanks
double drivetrain self made
etc......

speed target: 120kph minimum

RE: 74 inch Mono with 4-cylinder engine
 

Impressive:D Lets have a look have look under the hood:D

RE: 74 inch Mono with 4-cylinder engine
 

Welcome to the forum Matho!!

Beautiful build (as usual!!).

Looking forward to seeing more of her as you go and perhaps some video when she is ready.

RE: 74 inch Mono with 4-cylinder engine
 

whats up with the rudders mounted on an angle like that? never seen that before

RE: 74 inch Mono with 4-cylinder engine
 

Should be interesting to see how that works out .Boat looks fantastic though.
Mart

RE: 74 inch Mono with 4-cylinder engine
 

Im some cases the rudder angeled like that helps lock the boat in a turn.Ive seen it on several nitro nonos.

RE: 74 inch Mono with 4-cylinder engine
 

powerhouse took place to check a few things....still not ready to run....

RE: 74 inch Mono with 4-cylinder engine
 

That may be true with a single rudder but having two i would think one would counteract with the other and cause some issues.Be intersting to hear if its been tried before as ive never seen it before.
Mart

RE: 74 inch Mono with 4-cylinder engine
 

Any further work done Matho. Boat looks great can not wait to see it run.

Cobus

RE: 74 inch Mono with 4-cylinder engine
 

Have you run the rudder setup curious to here how it went.

Cobus

RE: 74 inch Mono with 4-cylinder engine
 

I use this rudder setup since the last 5 years on several mono hulls with success

RE: 74 inch Mono with 4-cylinder engine
 

Please can you explain the reasoning behind having them angled like this ?.Looks very odd to me and i would think it would cause serious problems especially at speed.
Mart

RE: 74 inch Mono with 4-cylinder engine
 

as stated at Jim

RE: 74 inch Mono with 4-cylinder engine
 

as stated at Jim's:

angled rudders: I use this concept since years with success. Theory behind: if the boat turns in a curve, the hull is tilting to the side. If the rudder axis is vertical the rudder blade acts now as a flap and will bring the bow down. Result: understeering and this leads to keel over.
If you'd ensure, that the rudder axis is vertically located if the hull has rolled to the side this understeering is gone.
But: in this case the boat wants to stay in the curve, the trick is now to find the best angle.

RE: 74 inch Mono with 4-cylinder engine
 

I can see what your saying to some extent but sureley the fact that there are two rudders one will counteract the other.To alter the hulls ride attitude in turns i use the rudder by angling it in or out from the transom,ive just never seen it done like that before at least not with dual rudders but thanks for the explanation ;).Not sure what you said on Jims you lost me there sory.
Mart

RE: 74 inch Mono with 4-cylinder engine
 

Video footage of it running would be great

RE: 74 inch Mono with 4-cylinder engine
 

Still no video footage???

RE: 74 inch Mono with 4-cylinder engine
 

So long as the outboard rudder is clear of the water once in the turn it should be OK, though if both rudders are in the water then I can see a lot of drag.

What an impressive engine though.

Nice work Matho.

Glenn
PS: Hi Martin!

RE: 74 inch Mono with 4-cylinder engine
 

John Finch covered the angled rudders in one of his books from Air Age, Advanced RC Boat Modeling I think it was. He said to run them at half of the angle of the bottom so if you have a 20 degree angle then tilt the rudder 10 degrees. This was only used on a single rudder though. I've been curious as to how well it worked. I think that I've only seen it used once.

RE: 74 inch Mono with 4-cylinder engine
 

Glenn i would have thought that as you start to turn the outboard rudder would be causing drag and acting like a trim tab causing all kinds of issues,i may be wrong but it seems logical to me.Proofs in the pudding and Matho says it works and ive no reason to disbelieve him but some video footage would be nice,would also love to see this engine working as ive only ever seen one running on the bench.
Mart
ps hi Glenn ;)

RE: 74 inch Mono with 4-cylinder engine
 

sorry for being late but I still miss my modified pistons for that engine due to a lot of F1 orders of my milling shop (supplier and friend of mine).
Hope to get the pistons end of coming week, so the test runs could be done mid of August.
So I am not able to show her running during the Heilbronn meeting, damned.
Current plan is to introduce her mid of September during a meeting at the Dutch border, I know there will be professionals (pics & vids) present...I will
give a note......

RE: 74 inch Mono with 4-cylinder engine
 

Look forward to seeing her run when you get it sorted,should be very impressive with all that power.
Mart

RE: 74 inch Mono with 4-cylinder engine
 

update: adapted double 2in1 exhaust system with selfmade manifolds (stainless steel, laser welded) and new designed damped pipes. First test schowed succes but due to too much water injection some power output issues. Have changed the water flow, next run planned during powerboat meeting in Heilbronn / Germany Sunday afternoon.

RE: 74 inch Mono with 4-cylinder engine
 

Wow man, i had not seen this post! congrats for that monster!
I can't imagine how will be the Heilbronn meeting this year, with boats like yours....I have also seen Torstens Apache 84 and that of his friend (yellow one) that surely they will be present. Well, keep us informed.

Regards

RE: 74 inch Mono with 4-cylinder engine
 

Mario ... you sure have to visit the Heilbronn-meeting sometime.

Bring some sleeping-gear , sure there will be someone with spare-room , in tent or caravan/campervan.

Micha Rissmann showed us a beautiful hull and engine-setup at the Eersel-meeting in Holland :