---------------------------------------------------------- M14PEngines-List Digest Archive --- Total Messages Posted Wed 09/28/22: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 11:36 AM - M14P sound during flight. (Sylvain April) 2. 02:08 PM - Re: M14P sound during flight. () 3. 04:40 PM - Re: M14P sound during flight. (Bill) 4. 04:46 PM - Re: M14P sound during flight. (Mark Pennington) ________________________________ Message 1 _____________________________________ Time: 11:36:02 AM PST US From: Sylvain April Subject: M14PEngines-List: M14P sound during flight. Hi all, I need your experience on the M14P. I am flying a Murphy Moose with a M14P 400HP engine spinning a MTV9 propeller.The airplane is on amphib floats. The engine runs OK with all the parameters in the green. But the engine mak e an unusual noise when we are in flight, it makes a kind of RAA_ RAA_ RAA with a period of about 2 seconds. At 1840 RPM it is very noticable at 2000 RPM it is louder, this noise can also be felt as a vibration in the floor of the airplane. The prop check OK no loose blade or damage, it perform nor mally, The RPM is constant no variation seen on an 3 1/8=92=92 analog gauge . We can not find anything loose on the airplane, The cowling is solid, the float guide wire are tight. Any idea what can cause this noise, it really seems to come from the engine .. Thanks Sylvain April Envoy=E9 =E0 partir de Courrier pour Windows ________________________________ Message 2 _____________________________________ Time: 02:08:24 PM PST US From: Subject: RE: M14PEngines-List: M14P sound during flight. I apologize for stating the obvious, but this has the feel of a prop being out of balance. r/ Mark Bitterlich Yak-50 N50YK From: owner-m14pengines-list-server@matronics.com On Behalf Of Sylvain April Sent: Wednesday, September 28, 2022 2:36 PM Subject: M14PEngines-List: M14P sound during flight. Hi all, I need your experience on the M14P. I am flying a Murphy Moose with a M14P 400HP engine spinning a MTV9 propeller.The airplane is on amphib floats. The engine runs OK with all the parameters in the green. But the engine make an unusual noise when we are in flight, it makes a kind of RAA_ RAA_ RAA with a period of about 2 seconds. At 1840 RPM it is very noticable at 2000 RPM it is louder, this noise can also be felt as a vibration in the floor of the airplane. The prop check OK no loose blade or damage, it perform normally, The RPM is constant no variation seen on an 3 1/8=92=92 analog gauge. We can not find anything loose on the airplane, The cowling is solid, the float guide wire are tight. Any idea what can cause this noise, it really seems to come from the engine. Thanks Sylvain April Envoy=E9 =E0 partir de Courrier pour Windows ________________________________ Message 3 _____________________________________ Time: 04:40:16 PM PST US From: Bill Subject: Re: M14PEngines-List: M14P sound during flight. We all seem to get a low frequency vibration or rough spot that it doesnt li ke. Does it follow when changing power setting? > On Sep 28, 2022, at 1:38 PM, Sylvain April wrote: > > =EF=BB > Hi all, > > I need your experience on the M14P. I am flying a Murphy Moose with a M14P 400HP engine spinning a MTV9 propeller.The airplane is on amphib floats. > > The engine runs OK with all the parameters in the green. But the engine ma ke an unusual noise when we are in flight, it makes a kind of RAA_ RAA_ RAA with a period of about 2 seconds. At 1840 RPM it is very noticable at 2000 R PM it is louder, this noise can also be felt as a vibration in the floor of t he airplane. The prop check OK no loose blade or damage, it perform normally , The RPM is constant no variation seen on an 3 1/8=99=99 analog gauge. We can not find anything loose on the airplane, The cowling is solid , the float guide wire are tight. > > Any idea what can cause this noise, it really seems to come from the engin e. > > Thanks > Sylvain April > > > > Envoy=C3=A9 =C3- partir de Courrier pour Windows > ________________________________ Message 4 _____________________________________ Time: 04:46:29 PM PST US From: Mark Pennington Subject: Re: M14PEngines-List: M14P sound during flight. I had the same issue until I dynamically balanced my propeller. Mark N621CJ On Wed, Sep 28, 2022 at 7:43 PM Bill wrote: > We all seem to get a low frequency vibration or rough spot that it doesnt > like. Does it follow when changing power setting? > > On Sep 28, 2022, at 1:38 PM, Sylvain April wrote: > > =EF=BB > > Hi all, > > > I need your experience on the M14P. I am flying a Murphy Moose with a M14 P > 400HP engine spinning a MTV9 propeller.The airplane is on amphib floats. > > > The engine runs OK with all the parameters in the green. But the engine > make an unusual noise when we are in flight, it makes a kind of RAA_ RAA_ > RAA with a period of about 2 seconds. At 1840 RPM it is very noticable a t > 2000 RPM it is louder, this noise can also be felt as a vibration in the > floor of the airplane. The prop check OK no loose blade or damage, it > perform normally, The RPM is constant no variation seen on an 3 1/8 =99=99 > analog gauge. We can not find anything loose on the airplane, The cowling > is solid, the float guide wire are tight. > > > Any idea what can cause this noise, it really seems to come from the > engine. > > > Thanks > > Sylvain April > > > Envoy=C3=A9 =C3- partir de Courrier > pour Windows > > > -- Replied from my iPhone. 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