Hi Jarek, Somehow that doesn’t sound right. In the ground, (with our Dimona) I plan on getting real close to 3000 RPM at full throttle (Part of our pre take off check to make sure it is in fine pitch.
Climb out (still at full throttle) RPM gets to around 3200 RPM. A point to note is the smaller engines like the Limbach are significantly affected by airspeed … ie the RPM will significantly increase with increasing airspeed (As opposed to the larger Lycomings for example where the RPM increase is much less. …. So on climb out you need to watch airspeed in fine pitch … above about 3300 RPM the prop noise gets really bad. Cross country flying … generally I cruise at around 2800 – 2900 and seem to get about 90 Kts. (12 to 13 L/hr) 3000 RPM will give close to 100Kts but increased fuel burn. (like 15L/hr) So I am a bit confused when you mention full throttle at 2500 RPM. It seems your prop is a bit too coarse. Maybe. Nigel Baker is the man to give you advice … Re rain … The Dimona wing is quite stable even in rain (as Laurie indicated) In fact the section Wolf Hoffman used was also used for some of the early composite gliders … very good low speed stability. I also “look after” 2 grob 109’s. They do have a rain problem … tend to turn into concrete sparrows when in rain. Best regards Ian Williams New Zealand From: [email protected] On Behalf Of Jarek Steliga Sent: Monday, 4 November 2019 10:06 a.m. To: [email protected] Subject: [DOG mailing list] H36 top speed Hello, I noticed that at level flight with the prop at cruise angle I can hardly reach the air speed of 150 km/h at RPM 2500 (full throttle). Is this something to worry about? Should not the top speed be around 190 km/h at RPM 3000? With the prop at "start" position the full throttle revs are 3000. Any comments please? Regards Jarek
