RE: [DOG mailing list] Hoffman propeller HO-V62-R / Issues withchanging positon to cruise
Tom A picture says a thousand words. That is a really good way to deal with the questions. Must be cold there at the moment looking at how Kristen is rugged up. Nige. From: dog@lists.riverland.net.au On Behalf Of kristinnow...@gmail.com Sent: Monday, October 15, 2018 5:09 AM To: dog@lists.riverland.net.au Subject: RE: [DOG mailing list] Hoffman propeller HO-V62-R / Issues withchanging positon to cruise Hi Jarek, With our newish prop (280 hours, also with aSN that starts with A), we shift into cruise at about 1800-2000 rpm, and find that when in flight (as opposed to pitch changes on the ground during run-up), the pull requires a bit more force, but the lever should only come out about 2-4 cm. I would describe the pull as steady but not sharp and not particularly slow. Kristn just uploaded a short video of me this https://m.youtube.com/watch?v=VyYbV802UAM Tom Sent from my Windows 10 device From: Jarek Steliga <mailto:jarekstel...@gmail.com> Sent: Sunday, October 14, 2018 13:57 To: dog@lists.riverland.net.au <mailto:dog@lists.riverland.net.au> Subject: Re: [DOG mailing list] Hoffman propeller HO-V62-R / Issues withchanging positon to cruise Tom and Nigel, Perhaps that's where the shoe pinches? Perhaps the manner I pull the pitch change handle needs to be looked into before other reasons are examined (shaft runout or two bearings not touching the driven plate simultaneously). It is unlikely that serious mechanical malfancions occur just a year since that particular prop had been released by Hoffman from overhaul, with the time of actual use not exceeding 20 hours. I have to admit that I always pulled the handle all the way and only now having read your remarks realize that perhaps that was completely wrong. Can the handle be pulled slowly untill the drop of RPM occurs or does it have to be a shorter but energetic jerk? Is the jury out on the RPMs at which the pitch change should be made? Is it 2200 or between 1800 and 1900 or what? Which works best for you? Regards Jarek niedz., 14 paź 2018 o 14:03 Nigel Baker mailto:ni...@limbachaustralia.com> > napisał(a): 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 <mailto:dog@lists.riverland.net.au> mailto:dog@lists.riverland.net.au> > On Behalf Of Tom Preisser Sent: Sunday, October 14, 2018 8:19 AM To: dog@lists.riverland.net.au <mailto: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 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 <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 >>
Re: [DOG mailing list] Hoffman propeller HO-V62-R / Issues withchanging positon to cruise
Hi All, Just some further observation on pitch change. The pitch change action is usually in three stages. The first is the easy take up of any slack in the cable until noticeable resistance is felt. The second is the continued pulling of the lever with some effort (but without pulling the lever very far!). The third is relaxing the the pressure on the lever. We have found that the process can vary quite a bit between props on the same aircraft depending on how the prop is configured after overhaul or resetting. We have also found that in addition to RPM, AIS is significant. eg the prop current not wanting to go into cruise pitch at 60-65kt but readily going in at 55-60kts at the same RPM. The current prop also has a much great difference between the fine and course settings requiring a significantly greater AIS for efficiency in course. Jarek, that there is an even clearance between the pitch plate and the two pitch change bearings was previously mentioned. You can make an easy visual check on this from the right hand side of the motor. Just look to see that the clearances look to be the same as this is very important as any even load applied will cause premature wear on the mechanism and worse, especially if you have been a little over boisterous in operating the lever. We have found the change usually works best at 2200 RPM. From P31 of the H36 manual... Hoffmann 4 H 36 DIMONA NormalProcedures 4.10 Cruise: To changepropeller position from Take—Off to Cruise the RPM must be between 2000 and2200. Pull and release the propeller control. A 500 RPM drop should occurwithout throttle adjustment. The throttle can then be opened for Cruise power(2500 - 3000 RPM) as required. Best Regards Laurie On Monday, 15 October 2018, 6:09:32 am AEDT, Jarek Steliga wrote: Michael, That convinces me further that my "pull" was ridiculously inadequate. I am beggining to hope that my troubles are soon going to be over, but can't be sure of course before trying to do it the way it is demonstrated in your clip. RegardsJarek niedz., 14 paź 2018 o 20:58 Michael Stockhill napisał(a): In my case, when on the ground before takeoff, I start with flat pitch at 1500 rpm, A fairly easy pull of an inch or so drops the rpm to 1200. A second more aggressive pull returns the rpm to 1500 rpm. I have noted over the last fifteen years that in flight the required force has progressively increased. I have mitigated that by dropping the rpm at pitch change. I am now probably closer to 1800 rpm than 2200. There is some evident wear on the pitch change rods, likely creating some binding due to greater centrifugal force at increased rpm. Not to suggest that this is yet an airworthiness issue. M On Sun, Oct 14, 2018, 12:38 PM wrote: Hi Jarek, With our newish prop (280 hours, also with aSN that starts with A), we shift into cruise at about 1800-2000 rpm, and find that when in flight (as opposed to pitch changes on the ground during run-up), the pull requires a bit more force, but the lever should only come out about 2-4 cm. I would describe the pull as steady but not sharp and not particularly slow. Kristn just uploaded a short video of me this https://m.youtube.com/watch?v=VyYbV802UAM Tom Sent from my Windows 10 device From: Jarek Steliga Sent: Sunday, October 14, 2018 13:57 To: dog@lists.riverland.net.au Subject: Re: [DOG mailing list] Hoffman propeller HO-V62-R / Issues withchanging positon to cruise Tom and Nigel, Perhaps that's where the shoe pinches? Perhaps the manner I pull the pitch change handle needs to be looked into before other reasons are examined (shaft runout or two bearings not touching the driven plate simultaneously). It is unlikely that serious mechanical malfancions occur just a year since that particular prop had been released by Hoffman from overhaul, with the time of actual use not exceeding 20 hours. I have to admit that I always pulled the handle all the way and only now having read your remarks realize that perhaps that was completely wrong. Can the handle be pulled slowly untill the drop of RPM occurs or does it have to be a shorter but energetic jerk? Is the jury out on the RPMs at which the pitch change should be made? Is it 2200 or between 1800 and 1900 or what? Which works best for you? Regards Jarek niedz., 14 paź 2018 o 14:03 Nigel Baker napisał(a): 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
Re: [DOG mailing list] Hoffman propeller HO-V62-R / Issues withchanging positon to cruise
Michael, That convinces me further that my "pull" was ridiculously inadequate. I am beggining to hope that my troubles are soon going to be over, but can't be sure of course before trying to do it the way it is demonstrated in your clip. Regards Jarek niedz., 14 paź 2018 o 20:58 Michael Stockhill napisał(a): > In my case, when on the ground before takeoff, I start with flat pitch at > 1500 rpm, A fairly easy pull of an inch or so drops the rpm to 1200. A > second more aggressive pull returns the rpm to 1500 rpm. I have noted > over the last fifteen years that in flight the required force has > progressively increased. I have mitigated that by dropping the rpm at pitch > change. I am now probably closer to 1800 rpm than 2200. There is some > evident wear on the pitch change rods, likely creating some binding due to > greater centrifugal force at increased rpm. Not to suggest that this is yet > an airworthiness issue. > > M > > On Sun, Oct 14, 2018, 12:38 PM wrote: > >> Hi Jarek, >> >> >> >> With our newish prop (280 hours, also with aSN that starts with A), we >> shift into cruise at about 1800-2000 rpm, and find that when in flight (as >> opposed to pitch changes on the ground during run-up), the pull requires a >> bit more force, but the lever should only come out about 2-4 cm. I would >> describe the pull as steady but not sharp and not particularly slow. Kristn >> just uploaded a short video of me this >> https://m.youtube.com/watch?v=VyYbV802UAM >> >>Tom >> >> >> >> Sent from my Windows 10 device >> >> >> >> *From: *Jarek Steliga >> *Sent: *Sunday, October 14, 2018 13:57 >> *To: *dog@lists.riverland.net.au >> *Subject: *Re: [DOG mailing list] Hoffman propeller HO-V62-R / Issues >> withchanging positon to cruise >> >> >> >> [image: smigło dimona nr.JPG] >> >> Tom and Nigel, >> >> >> >> Perhaps that's where the shoe pinches? Perhaps the manner I pull the >> pitch change handle needs to be looked into before other reasons are >> examined (shaft runout or two bearings not touching the driven plate >> simultaneously). It is unlikely that serious mechanical malfancions occur >> just a year since that particular prop had been released by Hoffman from >> overhaul, with the time of actual use not exceeding 20 hours. >> >> >> >> I have to admit that I always pulled the handle all the way and only now >> having read your remarks realize that perhaps that was completely wrong. >> Can the handle be pulled slowly untill the drop of RPM occurs or does it >> have to be a shorter but energetic jerk? >> >> >> >> Is the jury out on the RPMs at which the pitch change should be made? Is >> it 2200 or between 1800 and 1900 or what? Which works best for you? >> >> >> >> >> >> Regards >> >> >> >> Jarek >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> niedz., 14 paź 2018 o 14:03 Nigel Baker >> napisał(a): >> >> 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 *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
Re: [DOG mailing list] Hoffman propeller HO-V62-R / Issues withchanging positon to cruise
In my case, when on the ground before takeoff, I start with flat pitch at 1500 rpm, A fairly easy pull of an inch or so drops the rpm to 1200. A second more aggressive pull returns the rpm to 1500 rpm. I have noted over the last fifteen years that in flight the required force has progressively increased. I have mitigated that by dropping the rpm at pitch change. I am now probably closer to 1800 rpm than 2200. There is some evident wear on the pitch change rods, likely creating some binding due to greater centrifugal force at increased rpm. Not to suggest that this is yet an airworthiness issue. M On Sun, Oct 14, 2018, 12:38 PM wrote: > Hi Jarek, > > > > With our newish prop (280 hours, also with aSN that starts with A), we > shift into cruise at about 1800-2000 rpm, and find that when in flight (as > opposed to pitch changes on the ground during run-up), the pull requires a > bit more force, but the lever should only come out about 2-4 cm. I would > describe the pull as steady but not sharp and not particularly slow. Kristn > just uploaded a short video of me this > https://m.youtube.com/watch?v=VyYbV802UAM > >Tom > > > > Sent from my Windows 10 device > > > > *From: *Jarek Steliga > *Sent: *Sunday, October 14, 2018 13:57 > *To: *dog@lists.riverland.net.au > *Subject: *Re: [DOG mailing list] Hoffman propeller HO-V62-R / Issues > withchanging positon to cruise > > > > [image: smigło dimona nr.JPG] > > Tom and Nigel, > > > > Perhaps that's where the shoe pinches? Perhaps the manner I pull the pitch > change handle needs to be looked into before other reasons are examined > (shaft runout or two bearings not touching the driven plate > simultaneously). It is unlikely that serious mechanical malfancions occur > just a year since that particular prop had been released by Hoffman from > overhaul, with the time of actual use not exceeding 20 hours. > > > > I have to admit that I always pulled the handle all the way and only now > having read your remarks realize that perhaps that was completely wrong. > Can the handle be pulled slowly untill the drop of RPM occurs or does it > have to be a shorter but energetic jerk? > > > > Is the jury out on the RPMs at which the pitch change should be made? Is > it 2200 or between 1800 and 1900 or what? Which works best for you? > > > > > > Regards > > > > Jarek > > > > > > > > > > > > > > > > > > > > niedz., 14 paź 2018 o 14:03 Nigel Baker > napisał(a): > > 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 *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 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) > > > > On Sat, Oct 13, 2018 at 6:53 AM Jarek Steliga > 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 180
RE: [DOG mailing list] Hoffman propeller HO-V62-R / Issues withchanging positon to cruise
Hi Jarek, With our newish prop (280 hours, also with aSN that starts with A), we shift into cruise at about 1800-2000 rpm, and find that when in flight (as opposed to pitch changes on the ground during run-up), the pull requires a bit more force, but the lever should only come out about 2-4 cm. I would describe the pull as steady but not sharp and not particularly slow. Kristn just uploaded a short video of me this https://m.youtube.com/watch?v=VyYbV802UAM Tom Sent from my Windows 10 device From: Jarek Steliga Sent: Sunday, October 14, 2018 13:57 To: dog@lists.riverland.net.au Subject: Re: [DOG mailing list] Hoffman propeller HO-V62-R / Issues withchanging positon to cruise Tom and Nigel, Perhaps that's where the shoe pinches? Perhaps the manner I pull the pitch change handle needs to be looked into before other reasons are examined (shaft runout or two bearings not touching the driven plate simultaneously). It is unlikely that serious mechanical malfancions occur just a year since that particular prop had been released by Hoffman from overhaul, with the time of actual use not exceeding 20 hours. I have to admit that I always pulled the handle all the way and only now having read your remarks realize that perhaps that was completely wrong. Can the handle be pulled slowly untill the drop of RPM occurs or does it have to be a shorter but energetic jerk? Is the jury out on the RPMs at which the pitch change should be made? Is it 2200 or between 1800 and 1900 or what? Which works best for you? Regards Jarek niedz., 14 paź 2018 o 14:03 Nigel Baker napisał(a): 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 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 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) > > On Sat, Oct 13, 2018 at 6:53 AM Jarek Steliga 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 >> - You are subscribed to the Dimona Owners Group mailing list. To unsubscribe, send email to: dog-unsubscr...@lists.riverland.net.au
RE: [DOG mailing list] Hoffman propeller HO-V62-R / Issues withchanging positon to cruise
The Hoffman Prop Service Bulletin E34 rev B. (attached) that underlies both the EASA and FAA ADs is more clear in it's explanation that the blades in question are of pre-1983 manufacture. They also note that with these older design blades, no power on aerobatics are allowed. I guess that means with our 1998 “A” design (rounded tip style: HO-V-62 R/L160BT) we’re good to go try some! Kristin Sent from my Windows 10 device From: Laurie Hoffman via dog Sent: Saturday, October 13, 2018 18:21 To:; Rob Thompson; dog@lists.riverland.net.au Subject: Re: [DOG mailing list] Hoffman propeller HO-V62-R / Issues withchanging positon to cruise While carrying out a daily inspection a couple of years ago, I was surprised to discover a lot of vertical movement at the prop tips. Up till then I'd focussed more on lateral tip movement but since then I make a thorough check of both. Laurie Sent from Yahoo7 Mail on Android On Sun, 14 Oct 2018 at 9:14 am, Rob Thompson wrote: That is the old style props which didn't have enough lag screws to safely hold the blades in. Make sure you check the silicone seal on the inner blade where it goes into the hub. If a blade is coming out the silicon splits and you can see a definite gap in the silicone. Rob Rob Thompson 0429 493 828 (Please note that my new email address is amessageto...@gmail.com) On Sun, Oct 14, 2018 at 8:58 AM Michael Stockhill wrote: Tom, and others, The FAA just issued an airworthiness directive AD on Hoffman props used with Limbach 2000. It requires any blades that do not have an A or B suffix to the serial number to be replaced. It deals with possible loss of a blade, and the number and size of the retaining screws. I dodged that bullet M On Sat, Oct 13, 2018, 3:48 PM Tom Preisser wrote: 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 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) > > On Sat, Oct 13, 2018 at 6:53 AM Jarek Steliga 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 >> SBE034_B.pdf Description: Adobe PDF document - You are subscribed to the Dimona Owners Group mailing list. To unsubscribe, send email to: dog-unsubscr...@lists.riverland.net.au
