lml@lancaironline.net Mailing List Archive

<<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> << Lancair Builders' Mail List >> <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> On the other hand how many boats have variable-pitch props?<< Props on boats are pitched for cruise speed, similar to fixed pitch aircraft props. I run a 240 HP V-8 I/O in my Cobalt (Hey! I know it's hard to believe for this group, but there are some things besides flying - particularly when the wife likes boating about as much as flying in the Lancair) and a variable pitch prop on it would be a big help when accelerating from a stop. One has a choice of pitches and like an airplane, it's a compromise. Within limits, you can opt for a lower pitch for better acceleration but you give up top cruise speed. For you who've had to select the parameters of a fixed pitch prop for you Lancair - sound familiar? Somewhat like a fixed pitch aircraft prop, the drill for getting a move on is to cob the throttle and wait until the prop quits digging a hole in the water (cavitating because it's partially stalled) as the boat begins to move forward and onto the step (cruise condition). Taking a smaller bite by turning the pitch down, as we do in an airplane by pushing the blue knob fully forward on take-off, would be pretty neat. It's probably not done (at least on a standard pleasure boat, that I know of) because you don't have the same consequences from poor acceleration in a boat that you do in an airplane - like running out of runway! All said and done, I'd like a variable pitch prop on my boat - Man! Would that ever get a skier's attention! Dan Schaefer LML website: http://members.olsusa.com/mkaye/maillist.html LML Builders' Bookstore: http://www.buildersbooks.com/lancair Please remember that purchases from the Builders' Bookstore assist with the management of the LML. Please send your photos and drawings to marvkaye@olsusa.com.