Well, I should have read this cautionary remark myself. No flying with propeller in pitch position at RPM below 2300, full stop. I understand, no such restriction as regards flying with prop at start position.
Thank you and regards Jarek śr., 17 paź 2018 o 00:37 Laurie Hoffman via dog <[email protected]> napisał(a): > I just found the reference in the manual..P9. > No minimum RPM stated. > > > > *CAUTION* > > > > Avoid RPM during cruise below 2300 min –1! > > > > > > > > > > > On Wednesday, 17 October 2018, 9:19:12 am AEDT, Laurie Hoffman via dog < > [email protected]> wrote: > > > There's a requirement in the manual not to cruise between 2000-2300 rpm > (I'm pretty sure this is the nominated range). > I understand its a harmonics issue. > > Jarek if you intend to remain in the thermal I'd suggest that you > incrementally reduce the throttle and CHT back to the point where you > believe the prop is not generating drag (near but not to idle and dependent > on pitch setting). > > After all if the thermal or wave strength is sufficient to soar, maybe > somewhere above 230-250fpm, why not save fuel and engine wear? Ideally > switch off altogether once the CHT is low enough. The H36 soars better than > just about any other TMG. > > Sent from Yahoo7 Mail on Android > <https://go.onelink.me/107872968?pid=InProduct&c=Global_Internal_YGrowth_AndroidEmailSig__AndroidUsers&af_wl=ym&af_sub1=Internal&af_sub2=Global_YGrowth&af_sub3=EmailSignature> > > On Wed, 17 Oct 2018 at 8:39 am, Michael Stockhill > <[email protected]> wrote: > Others will have other thoughts, but effectively, with any fixed pitch > propeller, its maximum rpm at full throttle will follow airspeed. If you > left the prop in low pitch and leveled off and let the bird accelerate > without reducing throttle, the rpm would readily exceed maximum redline > rpm. Similarly, with the propeller in cruise pitch, its rpm will also > follow airspeed. Slowing from cruise airspeed to thermalling speed will > also reduce rpm. At the extreme, if these propeller had much more pitch or > bite, rpm at climb could be significantly less that what you are seeing. > Think of a bicycle kept in the wrong gear. But extreme pitch would be > unusable in anything other than level flight. Does it matter that your rpm > drops to 2200? I see that frequently at reduced airspeeds especially at > high altitudes where the engine produces less power. After 16 years, I > would say it is not a factor, and it is improbable that you will harm the > engine. If you could fly at an airspeed significantly less than stall > speed, maximum rpm with cruise pitch would be even less. You might do a > static runup before your next takeoff with the pitch in cruise position to > discover the minimum/maximum anticipated full throttle rpm. If you ever > inadvertenly try a takeoff with the prop in cruise pitch position, you will > likely see rpm of 2000-2200 as you accelerate to liftoff speed. > > On Tue, Oct 16, 2018 at 2:20 PM Jarek Steliga <[email protected]> > wrote: > > > > Hello, > > When trying to thermal with engine running and propeller in cruise > position, I noticed that the recommended RPMs of ca 2400, drop with > airspeed even as low as 2200. Is this harmful to the engine and should be > avoided? > > > Best regards > Jarek > > >
