3-blade prop RPM's on a piper arrow

KS Arrow PilotKS Arrow Pilot
in General Discussion
Quick question for anyone out there flying a piper arrow with a 3-bladed prop. I'm the new owner of a 1968 PA-28R-180. The previous owner installed a 3-bladed hartzell propeller. I notice shortly after take off, my RPM's go over the 2700 red line - closer to 2900. The engine is screaming. I pull the prop back to 2700 and continue climbing to 1000 feet AGL and pull back throttle and prop to 25's like I was trained. Since the RPM gauge is original from the 2-bladed prop, do the same "red-line's" apply? Or is it OK to go over 2700 RPM's for a short bit? I plan on discussing with my local A&P, but thought I would check with this site too in case there are other Arrow owners with experience. Thanks

Comments

  • flyguydonflyguydon
    No. It is never OK to go over the redline of 2700. It is, however, ok to run it anywhere between idle and 2700. The 2 blade Arrows have a "red zone" where they do not suggest prolonged operation at those RPMs. I have a 3 blade and my tach has been refaced to get rid of the red zone, so I forget exactly where it is, but I think it was 2100 - 2300. Anyway, a 3 blade is fine from idle to redline. There is an adjustment on your governer that needs to be made so yours stays at 2700 a full speed.

    25 is rather high for cruise. 24/24 is very standard. A 3 blade makes it possible to use anywhere for cruise... and sometimes it is cool to go say 2200 or even 2100. Good fuel burns there and real quiet... It is approved to leave the MP at 24 and pull the prop down to 2100. You only lose a few kts in cruise there.

    To further clarify if it is OK to run your engine over redline... it is supposed to be required to pull the engine down for an inspection (sort of like a prop strike) if you EVER run it over redline.

    Get your governor adjusted... or at least get the accuracy of your tach checked... as it is not uncommon for tachs to be "off" a hundred or two. In fact, it is more likely that your tach is not correct than that your governor is out of adjustment. Unless nobody ever adjusted it after the 3 blade conversion??
  • tooth32@aol.comtooth32@aol.com
    If I am not mistaken isn't the red zone for engines that do not have counter balanced crankshafts. I didn't think it had anything to do with the prop, although mine is a 200 arrow.
    Never a good idea to go above 2700 rpms, definitely get the prop governor adjusted. My guess is it is time or an overhaul on it.
    Let us know how it goes.

    Randy
  • flyguydonflyguydon
    The 2 blade Arrows have a red zone. The 3 blade conversion eliminates the red zone.
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