Hi Jarek I checked the Hoffman Prop manual and indeed you are correct. However all on this list will say 2200 RPM I think.
Expect a drop of 200 rpm for cruise so aim for a drop of 250 momentarily. The idea is to provide enough clearance for the slide to move into place in the Centre stem nut shoulder without the RPM dropping so far that the centrifugal force drops so much the slide will not stay out in the cruise position. It is a balancing act between RPM and hand force on pull handle. As Tom says if you pull the change handle far enough back it will rumble like hell as the blades are stalling due to too high an angle of attack. It won’t do any damage but is unnerving. This takes a little finesse but once mastered you will find it easy enough. Nige. From: dog@lists.riverland.net.au <dog@lists.riverland.net.au> On Behalf Of Tom Preisser Sent: Sunday, October 14, 2018 8:19 AM To: dog@lists.riverland.net.au Subject: Re: [DOG mailing list] Hoffman propeller HO-V62-R / Issues with changing positon to cruise Perhaps you are pulling the handle too far out ? Just pull it a little, because if you pull it too far the prop will rumble, the rpm will fall too much, and no change to cruise will happen. Let us all know what you discover. On Friday, October 12, 2018, Rob Thompson <amessageto...@gmail.com <mailto:amessageto...@gmail.com> > wrote: > 1- Normally the RPM on change should be 2200 to go into cruise. > 2 - Sounds like the pitch change/feather plate on the rear of the prop is not > running true or alternatively the two bearings that contact it are not > touching at the same time. > Use a finger dial guage to check if the plate is true. > regards > Rob > Rob Thompson > 0429 493 828 > (Please note that my new email address is amessageto...@gmail.com > <mailto:amessageto...@gmail.com> ) > > On Sat, Oct 13, 2018 at 6:53 AM Jarek Steliga <jarekstel...@gmail.com > <mailto:jarekstel...@gmail.com> > wrote: >> >> >> Hello, >> I am quite new here (have owned Dimona for only 3 months). >> Despite scrupulously folliowing the instructions regarding the required >> RPM-s of between 1800 to 1900 at which the propeller pitch is changed from >> START to CRUISE in midair, I have only succeedded twice despite numerous >> attempts. Also pulling the pitch lever in the cockpit results in scary >> vibrations which discourages me from continuing my trial and error methods. >> Can someone please help? >> >> Best regards >> Jarek >>
