Twin cat props.. in or out ?

[drwayne]

Hi
Have seen both setups run successfully..what is your considered opinion as best ?
Props under rear transom overhang.. or outside/free from there ?

[drwayne]

This will be for 1100-1400 size c5000

[MarkF]

I would run them out.
I would think the prop blast might hit the hull causing some weird effects if there in.

Mark

[nata2run]

Reading on the German forum (spending a bit of time there lately), 90% of the "mad Germans" run them IN for bigger props and saw/max speed, you can see it on the spray they leave behind as well, but I reckon the hull will turn better if you run them outward, maybe because less air/wash around the rudder. Even looking on youtube on the HPR Models, most I see run them IN. Speed in excess of 165km/h - 200km/h though. Some on small Lehners!!

Maybe Wayne, when we meet on the big lake I'll change the props/shafts around :) By then there will be a little sticker on the side of the boat reading "Lehner Powered" watch out Wayne

I'm gonna run mine out for now

[drwayne]

Hi.
I need to measure the area on this cat's bum..
You measured transom overhang at just 37mm stinger height.. that limits me to around 55mm props.
On some 100% offshore they extend behind..some with air traps to aerate them also... else prop wash pushes the nose under.
Still considering Lehhner.. a lot of coin for oval racing, M8.

Ive read the De forums also.. most those 90% run +12S2P (+4Kg) of battery.. here in Au our rules limit us to just 1900gms or 12S1P.
That extra 33% mass makes a large change to hull dynamics.

Hahaha on your larger lake you dont scare me , matey !
You've a physical disability where the trigger finger doesnt reach WOT

000_0029.JPG

[nata2run]

Well, firstly from centre of props shaft to bottom of hull is 33mm so it will fit quite a big prop. More news, my props are not under hull but over hanging by 10mm but still 10mm behind rudder. So really no limit there apart from too big props might be unstable. More people are using propshop 4518/3 and are getting close to 200km/h mark

Trust me, finger not disabled! The fear of crashing, wallet damage, makes me think twice.....for now. Might be game sooner than you think.