Hi Jarek, Have you made any adjustments to the propeller pitch whilst you have been having these problems? Also have you done a compression test? regards Rob
Rob Thompson 0429 493 828 (Please note that my new email address is [email protected]) On Sun, Jan 5, 2020 at 8:48 AM Jarek Steliga <[email protected]> wrote: > Hi Ian, > > I have just stumbled upon this article > https://www.aopa.org/news-and-media/all-news/2005/august/pilot/soar-like-a-sea-gull > where > I found the following statement: " Acceleration is satisfying, especially > after you discover that the engine, which nominally produces 80 horsepower > at 3,400 rpm, only puts out 50 horsepower or so in the 2,500-to-2,800-rpm > actual operating range." > > This made me think again if perhaps my Dimona is flyable after all even > if it clearly falls short of your benchmarks. The fact is that prior to the > recent replacement of the throttle shafts and butterflies, the engine used > to rev up to 2700 static, but it was pretty erratic and uneven and I > remember distinctly I could hold the plane in place with just the use of > the handbrake (no choks), while now I need the chocks even if the max RPM > are just 2500. > > I wonder if you would find time and interest to have a look at this > article. > > Best regards > Jarek > > P.S. I discovered with some satisfaction that you have some Polish made > (or at least) designed gliders like PW5, Cobra and Puchatek in your fleet. > > > > > On Fri, 3 Jan 2020 at 21:58, Jarek Steliga <[email protected]> wrote: > >> Hello Ian, >> >> Thank you again. I know enough. There's nothing for it but to roll up my >> sleeves and find the reason for this slow rotation rate of my machine along >> the suggestions made by yourself and other people under this thread. I am >> going to report to you when/if I manage to rectify the situation. >> >> Best regards >> Jarek >> >> >> >> On Fri, 3 Jan 2020 at 21:27, Ian Williams <[email protected]> wrote: >> >>> No it’s not spectacular really. We have a older Grob 109 which I >>> refitted a 2400 Limbach into some years ago. It can cruise at 95 to 100 kts >>> However the Dimona is much better at the slow speed end. It is very >>> stable great thermalling stability. It can thermal well at 45 kts Wheras >>> the Grob 109 begins to get uncomfortable if u get below 55 kts >>> >>> Best regards >>> Ian Williams >>> ZK-GCB >>> >>> Sent from my iPhone >>> >>> On 4/01/2020, at 8:43 AM, Jarek Steliga <[email protected]> wrote: >>> >>> Hi Ian, >>> >>> Thank you. Yes, I remember you mentioning these figures before. I am >>> wondering if your plane is exceptionally fast. Do you think the other >>> owners enjoy the similar performance? >>> >>> Best regards >>> Jarek >>> >>> >>> >>> On Fri, 3 Jan 2020 at 19:21, Ian Williams <[email protected]> wrote: >>> >>>> hi Jarek, >>>> Typically I look for close to 2800 to 2900 RPM static as part of our >>>> pre take off checks to confirm the prop is in fine pitch >>>> On climb out provided the airspeed is around 60 kts or so the RPM gets >>>> to about 3200. Any more and the noise factor increases >>>> Best regards >>>> Ian Williams >>>> ZK-GCB >>>> >>>> Sent from my iPhone >>>> >>>> On 4/01/2020, at 4:55 AM, Jarek Steliga <[email protected]> wrote: >>>> >>>> Hello, >>>> >>>> I apologize for laboring the point, but what is the max static RPM on >>>> your H36 / Limbach 2000 / Hoffman H0-V62 prop? Do all of you reach >>>> consistently way above 2500 RPM? >>>> >>>> >>>> Best regards >>>> Jarek >>>> >>>> >>>> >>>> On Wed, 1 Jan 2020 at 12:28, Jarek Steliga <[email protected]> >>>> wrote: >>>> >>>>> Hello Rob, >>>>> >>>>> Thank you for your reply and all the best in the New Year! >>>>> >>>>> Yes, I have synchronized the carbs with vacuum gauges. The readings >>>>> were pretty consistent throughout the range of throttle opening. However I >>>>> noticed how throttle butterflies will not track together as they open >>>>> wide. >>>>> They are both fully closed at idle but aren't aligned at full throttle. >>>>> Should this worry me even if both sides seem to be synchronized when it >>>>> comes to the vacuum values? >>>>> >>>>> >>>>> Best regards >>>>> Jarek >>>>> >>>>> On Sun, 29 Dec 2019 at 22:45, Rob Thompson <[email protected]> >>>>> wrote: >>>>> >>>>>> Have you synchronised the carbs to make sure the throttle butterflies >>>>>> are tracking together with a full range of movement? >>>>>> regards >>>>>> Rob >>>>>> >>>>>> Rob Thompson >>>>>> 0429 493 828 >>>>>> >>>>>> >>>>>> >>>>>> On Mon, Dec 30, 2019 at 6:05 AM Jarek Steliga <[email protected]> >>>>>> wrote: >>>>>> >>>>>>> >>>>>>> Ian, >>>>>>> >>>>>>> Thank you. I will definitely look at both plungers. >>>>>>> >>>>>>> Best regards >>>>>>> Jarek >>>>>>> >>>>>>> On Thu, 26 Dec 2019 at 00:00, Ian Mc Phee <[email protected]> >>>>>>> wrote: >>>>>>> >>>>>>>> I go on colour (av gas for testing for colour), CHT (do all 4 >>>>>>>> digitally) and maximum deviation is 8deg C but often ass low as 5 deg C >>>>>>>> and EGT with a cheap dual analogue and it is of limited use. >>>>>>>> >>>>>>>> I seem to remember the bottom jet and needle controls fuel at 80% >>>>>>>> power to full power and below that is the top jet controls fuel for >>>>>>>> cruise >>>>>>>> etc. >>>>>>>> >>>>>>>> I am more familiar with Bing's these days but the CD150 is >>>>>>>> similar. 8 do know if there is any sucking of air inlet manifold it >>>>>>>> effects both sides and not just the side of the leak. >>>>>>>> >>>>>>>> A bit of an aside but been having issues going onto full power on >>>>>>>> take off and if done real slow over 15 seconds no issues. Do it over >>>>>>>> 5 >>>>>>>> sec engine would not go full revs at first till you had just broken >>>>>>>> ground. >>>>>>>> I even added extra spring to bring it better to full throttle. Then >>>>>>>> suggested to me as was not running rich it was a pin hole in diaphragm >>>>>>>> but >>>>>>>> was perfect BUT on second carb I noticed some scour marks on engine >>>>>>>> side of >>>>>>>> the plunger with the needle. I polished the aluminium first with emery >>>>>>>> then worked up with 400, 600 and 1200 wet and dry. Totally fixed. >>>>>>>> Plunger >>>>>>>> was binding or sticking on its way up. So simple to fix. This has been >>>>>>>> creeping up on me over 9 months. >>>>>>>> >>>>>>>> >>>>>>>> Ian McPhee >>>>>>>> +61 428847642 >>>>>>>> Box 657 Byron Bay NSW 2481 Australia >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> On Thu, 26 Dec. 2019, 09:01 Jarek Steliga, <[email protected]> >>>>>>>> wrote: >>>>>>>> >>>>>>>>> Hello Martin, >>>>>>>>> >>>>>>>>> I did the very opposite thing! Suspecting that it was the >>>>>>>>> insufficient supply of fuel that caused the problem, I lifted the >>>>>>>>> metereing >>>>>>>>> needles all the way up from neutral (flush). This manoeuvre changed >>>>>>>>> nothing >>>>>>>>> except (predictably) making the plugs even blacker. The CHT behave >>>>>>>>> normally. I am afraid the snag lies elsewhere, but many thanks for >>>>>>>>> your >>>>>>>>> suggestion. >>>>>>>>> >>>>>>>>> >>>>>>>>> Regards >>>>>>>>> Jarek >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> On Wed, 25 Dec 2019 at 22:30, Martyn Cook <[email protected]> >>>>>>>>> wrote: >>>>>>>>> >>>>>>>>>> Hi Jarek >>>>>>>>>> >>>>>>>>>> Maybe now that you have blocked the air leaks around the throttle >>>>>>>>>> shaft the engine is running a little rich? That would certainly >>>>>>>>>> reduce >>>>>>>>>> your peak rpm. >>>>>>>>>> >>>>>>>>>> I have found getting the mixture correct on each side to be a bit >>>>>>>>>> tricky. I adjusted the mixture on mine a bit at a time, watching the >>>>>>>>>> degree of "blackness" on the spark plugs, plus the CHT behaviour. >>>>>>>>>> But I >>>>>>>>>> was taking it for a flight then adjusting when back on the ground. >>>>>>>>>> >>>>>>>>>> Maybe others know of a way to get the mixture setting correct on >>>>>>>>>> the ground? >>>>>>>>>> >>>>>>>>>> Kindest regards >>>>>>>>>> Martyn >>>>>>>>>> >>>>>>>>>> -- >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> On 26/12/19 9:37 AM, Jarek Steliga wrote: >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> Hello everyone, >>>>>>>>>> >>>>>>>>>> I have replaced the throttle shafts and the throttle plates. >>>>>>>>>> Fortunately it looks like no rebushing will be necessary. The engine >>>>>>>>>> became >>>>>>>>>> far more stable now and responds precisely to throttle control >>>>>>>>>> inputs. >>>>>>>>>> Clearly the badly worn out throttle shaft was (at least partly) >>>>>>>>>> where the >>>>>>>>>> shoe pinched. However, strangely enough, the engine will not rev up >>>>>>>>>> beyond >>>>>>>>>> static 2500 RPM. See the attached video. I am faced with yet another >>>>>>>>>> conundrum. >>>>>>>>>> max static RPM 2500.3gp >>>>>>>>>> <https://drive.google.com/file/d/17rdy2gc83H4FCpMXqlTOlBn-KBV8kVJA/view?usp=drive_web> >>>>>>>>>> Also the engine will not respond to throttle control beyond ca 4 >>>>>>>>>> cm before the max power position. >>>>>>>>>> >>>>>>>>>> I am not sure if it's safe for me to attempt a take off as before >>>>>>>>>> the throttle repair, the engine had reved up to static 2600 / 2700. >>>>>>>>>> >>>>>>>>>> I am looking forward to your thoughts. >>>>>>>>>> >>>>>>>>>> Best regards >>>>>>>>>> Jarek >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>>
