[Public-List] Standard Prop Size and Pitch

Mike Lehman sail_505 at hotmail.com
Thu May 22 09:09:18 PDT 2008


Brian,
 
12" diameter is actually much better since on the A30 the prop is in an aperature. The experts will tell you that the prop diameter should not be more than 80% of the aperature opening. With a smaller prop there is less prop wash and less noise. Higher RPMs help to reduce carbon build up. An engine running at a low RPM under laod is often laboring because you are not high enough on the designed power curve. Tis laboring promotes carbon build up.Mike Lehman  ><((((º>`·.¸¸.·´¯`·.¸><((((º>`·.¸¸.·´¯`·.¸><((((º>  > Date: Thu, 22 May 2008 11:20:22 -0400> From: Bpalmer at DigitalArsenal.com> To: public-list at lists.alberg30.org> Subject: Re: [Public-List] Standard Prop Size and Pitch> > On L'Esprit, I've got an Atomic 4 with the 13x7 prop. The engine runs> strong and smooth, but when in gear, I can't rev higher than maybe> 1900RPMs. If I push the throttle higher, the engine doesn't go any faster.> I think it's just that the engine is working hard enough that it simply> can't spin the prop any faster under that load.> > It's not a problem, since I can motor along at 6 kts or so on flat water. I> hear people mentioning 2300RPMs... It would be nice to have this as reserve> power if I was motoring against the wind and chop or something. Do those of> you who also have A4s with the standard 13x7 2 blade find the same> limitation?> > On a side note, Towney mentioned before that he had his 13x7 prop turned> down to a 12x7 prop after getting a nick in it or something. He said the> engine ran like never before! He had the same problem I speak of, with the> RPMs never getting high enough to take advantage of ideal HP and torque> available at those higher RPMs. He said that once the prop was smaller it> felt like it was a better match for the A4.> > -Brian Palmer> _______________________________________________> These businesses support your Association:> http://www.alberg30.org/store/A30supporters.html> Please support them.> _______________________________________________> Public-List mailing list> Public-List at lists.alberg30.org> http://lists.alberg30.org/listinfo.cgi/public-list-alberg30.org
_________________________________________________________________
Give to a good cause with every e-mail. Join the i’m Initiative from Microsoft.
http://im.live.com/Messenger/IM/Join/Default.aspx?souce=EML_WL_ GoodCause
 1211472558.0


More information about the Public-List mailing list