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profqwerty - n/a
17-Jul-07, 04:11 PM
Hi all,



I've just ordered a mirage hull from K&M, should be here in about 5 weeks.



I have some questions about the thrust system though:



The coupling block which KM sells,

http://www.avdw32.dsl.pipex.com/images/bearingnb.jpg

can it be replaced with a coupling shaft on from the flex coupling, with 2 pillow block bearings?



I'm guessing the coupling block is to keep the bottom pulley of the belt drive dead steady whilst the engine moves slightly? Otherwise is there any other use it has?



I'm planning on building the engine frames myself.

I'm assuming the fan shaft is welded onto the frame, and the drive hub sits on this with bearings?



How do people do minor adjustments to the positioning of the fanshaft to center it? guessing 2 bolts at right angles can be turned to shift it?



The initial build will be with a 447, then i will put something else on later.



What's the best way to do steearing on a mirage - single or double rudders?



What sort of fan is used in the lift duct? 3z blades in a 9 blade hub right? i'm guessing 9 blades are used to generate the higher pressure/low flow rates.



Are there any other issues anyone can think of at the moment?

I have loads of fittings from my old hover; I only need 2 more skirt segments!

Thanks for the help!

Toby

bryan - n/a
18-Jul-07, 08:38 PM
Hi i have had great success with three craft using KM bottom block bearings. Using pillar block bearings are a step back in time.If you spend time setting your drive pullies and belt tension it should need no adjustment. In my experiance you might be better off putting more tension than usual on the belt when using the Rotax twin and a centreflex coupling this will stop the osolation on start up. Good luck on the build!