fbpx

 

Greetings, gentlemen

During the very first ground run, of a new 912S2 engine, RPM indicator goes to yellow arc.

During take-off, A/c climb rate unsatisfactory; RPM indicator crosses red line.

During flight, RPM indicator erratic, sometimes on yellow arc, also on red line.

Engine done 20 hrs only, A/c is P-2008J (not new),Prop: Hoffman HO-17G

Should we suspect malfunctioning of the overload clutch? 

Please provide your suggestions

Regards,

Ray.   

 

  • Re: Low climb rate-RPM indicator in red

    by » Yesterday


    Hello Ray

    It is doubtful you are having issues with the overload clutch with an engine that has only 20 hours. Most likely you are seeing an indication error on your instrument. With that said, the Yellow arc, and the Redline doesn't provide enough information regarding what your actual RPMs are. Max RPM for 5 min is 5800 RPM (take-off RPM) and cruise is normally set to 5300 - 5500 RPM.


  • Re: Low climb rate-RPM indicator in red

    by » Yesterday


    Thank you, this point is well taken.

    Actually, the prime issue is R.O.C. not satisfactory. That means, the propeller isn't able to convert engine power to forward thrust. Since the clutch connects the engine to the propeller, it is possible that the clutch is slipping. Hence we suspect something could be wrong with the propeller or with the clutch. Another propeller was also tried out, but no change. Thus the focus is on the clutch, though not quite sure. 

    This may also address the RPM issue. Propeller load is not being correctly felt by the engine due to slipping clutch and hence engine is free to rotate with low load, thus allowing RPM to go up. Does it sound logical?  kindly comment. If anyone had experience of working with a defective / worn out clutch, it would be great to share. Thanks.

    Ray


  • Re: Low climb rate-RPM indicator in red

    by » Yesterday


    What type of prop setup is on this Tecnam?

    I have a couple of Tecnams at my field. Is it a constant speed / variable prop or ground adjustable?


    Roger Lee
    LSRM-A & Rotax Instructor & Rotax IRC
    Tucson, AZ Ryan Airfield (KRYN)
    520-349-7056 Cell


  • Re: Low climb rate-RPM indicator in red

    by » Yesterday


    hi Roger,

    Thanks for your response.

    It's a  Hoffman fixed pitch wooden prop, model no. HO 17G HMA 174 177C. Would you need any other information, please let me know.

    Looking for your expert opinion..

    Regards,

    Ray


  • Re: Low climb rate-RPM indicator in red

    by » 8 hours ago


    We could use a few more numbers to make a good decision. When you are in level flight what is your maximum rpm? If it's over 6K don't go there. Let us know if it's under 5500 rpm in level flight at WOT. If it's a fixed pitch and the pitch is either way to corse or too flat then you may want to install a ground adjustable prop. I've put several on Tecnam's and all had a far better performance. All my guys had too course a pitch and they went to a Sensenich 68" 3 blade ground adjustable prop with really good improved performance. Tecnam approved this prop in about two days.


    Roger Lee
    LSRM-A & Rotax Instructor & Rotax IRC
    Tucson, AZ Ryan Airfield (KRYN)
    520-349-7056 Cell


You do not have permissions to reply to this topic.