A90/A45 Engines

[TimD]

Now those guys know the meaning of endurance racing :

Hammer San, where are you?

TimD racing: to be old and wise you must first be young and stupid.

 

[Ian Inverarity]

Hey Craig,

Yeah, yeah, save it for boat races!!

Nitrocrazed racing: You should quit while I'm ahead.....

 

[Ian Inverarity]

Prop Jocky,

To turn left you would probably want to put the rudder on the LHS for a mono. As a mono banks in to a RH turn with the rudder on the RHS the rudder gets deeper in the water. Going left as the boat banks left the rudder gets shallower, which is bad news! Put the rudder on the LHS and it would work.

Of course I am talking race boats here. For sport boats you can simply have one rudder in the middle or two rudders either side of the prop.

Nitrocrazed racing: Retired due to electrical failure. Conrod went thru the side of the block knocking the alternator off.....

 

[Twin_k90]

you make a good point with the rudder there ian, lucky i can change mine over in about 5min!!

Kingcraft racing : young dumb and full of .......

 

[Ian Inverarity]

Dale,

You wont need to, we wont be having a reverse direction race! :

Ian.

 

[EatMyShortsRacing]

You know I am going to get all inspired and start taking the boats out locally...

I was trying to figure out the last time I ran a boat in Victoria and I think it was the very first run of my 90 Seaducer before the 2000 nats...

Sad isnt it?

EMS Racing Yes that is me behind you, prepare to be lapped

 

[Ian Inverarity]

Craig,

Looking at the Western Districts calendar on their website there should be plenty of opportunity to get out racing again!

Last time I raced in Victoria was the 98 state titles. But I dont live there....

Ian.

 

[Twin_k90]

i have never raced in melbourne! i have raced in adelaide tho!!

 

[TimD]

I have never raced boats in Melbourne........ raced cars there a few times though.

 

[Hammerhead]

Sorry Anders! I couldn't find a close up. This is the only boat that I could find that had a nelson in it.

Hmm! Wont post my pic. I will try again later

Hammer

 

[[email protected]]

I like the idea of this demolition derby Le Mans style race. I'd be willing to fly from San Francisco USA to enter tha race w/my Twincraft. I've asked people here to do figure 8 but they want no part of it.

 

[j irwin]

[flash=200,200] Ron , keep on cutting that pipe till see the boat starting to sag in the corners then move it out 1/4 inch and it should be right on, Send me the info on the sponsership for the 21/45 outb classes, lol, jim irwin

 

[Ian Inverarity]

Mike,

Have you been following the 30cc thread? There has been a fair bit of discussions about the A100 there.

Ian.

 

[Ian Inverarity]

TimD

Did you see the pics of the A-90 in bits on Mike's site? Note crank construction and rear bearing mount which forms the sealing face for the disc.

Craig,

Note the small oil grooves on the face of the big end of the rod? That's new...

Ian.

 

[TimD]

Yep,

Sure did. What's with the grooves milled into the disk?

Tim.

 

[Ian Inverarity]

Tim,

That is the non-sealing face of the disc that has the grooves in it. I guess it is to lighten the disc in that area to reduce the out-of balance mass opposite the cut-out? :-

Ian.

 

[TimD]

Ian,

That makes sense.... Although I would have thought they could have factored that in to balancing the crank as the disk appears to be pinned to it.

Tim.

 

[Mike Bontoft]

Yes Ian

Its an interesting thread for me. Twenty something years ago I built a boxer style twin out of 2 OPS 29s which I still have. It revved like there way no tomorrow but didnt like pulling a prop. The problem was fuel starvation to the front cylinder. Last year I built an inline twin out of 2 zenoahs , crank pin problems put an end to that one. I guess I like twins. I can probably dig up pictures if your interested.

 

[EatMyShortsRacing]

I was told the milling on the disc aided the fuel flow or fuel mixing somehow.

EMS Racing

 

[Ian Inverarity]

Tim,

I dont think the balacing is so fancy, but yes the disc is bolted to the crank. Being aluminium it would be less out of balance mass than a steel disc.

Craig,

Yes, well I saw that claim too, but I dont believe it. If anything it would be aiding in centrifuging the mixture to the perimeter of the disc which would be of no benefit.

Mike,

A multi-cylinder would be interesting, but a 30cc single cylinder is more like what we are after. I am going to do some more design work on it soon. Maybe mr A could do some custom parts for us if we provide drawings?

By the way Mike, if you look into those pipes for the A motors from the engine end (using a torch) do you see a series of baffles with progressively smaller holes?

Ian.