How would you like to hand prop one that stops in the 2 & 8 position. It is scary enough hand proping from the 10 o'clock position. You young bucks probably never were trained on hand proping. We had no other choice on light aircraft "back in the day". And I really did walk 5 miles to school up hill, but only in one direction.
Andy > David, > > 11 and 5 viewed from the cockpit is not correct and will cause vibration. > Viewed from the cockpit is should be more like 2 and 8. > > Kevin1 > > > > --- In [email protected], "drdlhammond" <drdlhamm...@...> > wrote: >> >> Hi Kevin, >> >> We had the prop off during the March 2010 annual and it was re-mounted >> in the same spot on the hub. Engine vibration following the annual was >> no different than prior to the annual. The increase vibration was noted >> following replacement of the rubber motor mounts. >> >> After re-indexing the magnetos during the annual (to obtain proper >> impulse coupling for hand propping the engine), the prop stops at the 11 >> and 5 position as viewed from the cockpit. Again, the engine vibration >> post-annual was not different that pre-annual. >> >> Thanks, >> David >> N95CV >> >> --- In [email protected], "Kevin" <kgassert@> wrote: >> > >> > And make sure the prop is mounted in the proper spot on the hub. When >> your engine stops does it usually stop with the blades at about 10 and >> 4 looking at the front of the aircraft from outside? >> > >> > Kevin1 >> > >> > >> > >> > --- In [email protected], "BobD KSVE" <bevbobdtn@> wrote: >> > > >> > > David, >> > > When I bought my coupe N3047H, it had a bad vibration. After doing >> what you are doing, motor mounts, clearances, engine stuff, dynamic >> balancing, we removed the prop and took it to a prop shop. They >> promptly red tagged it!! (someone had drilled a couple of extra >> holes in the back of the hub) >> > > >> > > A new prop and dynamic balance and empty wallet later and I could >> finally make out the writing on the gauge faces while flying. >> > > Bob D. >> > > 1946 415E N3047 "Honey" >> > > Susanville, CA >> > > >> > > >> > > --- In [email protected], "drdlhammond" <drdlhammond@> >> wrote: >> > > > >> > > > Hi John, >> > > > >> > > > How can I/we tell if the rubber motor mounts are bad??? The AP >> thought they looked normal (i.e. compared to others he had >> replaced). His torque wrench was "validated" about 1-2 months >> prior to my job (he questioned both the 60 inch pounds - too tight >> - and his wrench but a second, older wrench was almost identical). >> Should we further tighten the mounting bolts? >> > > > >> > > > Both magnetos checked good during the March annual and both have >> been acting "normally" since (i.e. no difference has been noted >> during engine run up prior to take off). Yes, the right exhaust >> pipe vibrates enough to touch the cowling at its exit hole (has >> since I bought the plane a little over 2 years ago). Otherwise, >> we have not found anything that touches the cowling. I will pass >> along the suggestion to check for valve spring and lifter >> malfunctions. >> > > > >> > > > The engine vibration reminds me of the old K&B 0.35 >> nitro/methane/castor oil model airplane engines we used in the >> late '60s and early '70s. These engines were mass produced and >> inexpensive. Regardless of how well the prop was balanced, they >> vibrated! At the time, older modelers told me these engines were >> not internally "balanced" and thus their vibration. How much >> engine vibration is "normal" for a 43 year old 4 cylinder 4 stroke >> engine??? >> > > > >> > > > Thanks for your input! >> > > > >> > > > David >> > > > N95CV >> > > > >> > > > --- In [email protected], John Cooper <john@> wrote: >> > > > > >> > > > > On 8/14/2010 10:32 AM, drdlhammond wrote: >> > > > > > We could NOT tighten the mounting bolts to the prescribed 60 >> inch >> > > > > > pounds (we had metal to metal contact between the engine and >> the >> > > > > > mount). At 45 inch pounds there was very little clearance so >> we >> > > > > > settled on 40 inch pounds. >> > > > > >> > > > > OK, there's something wrong there. Bad rubbers, bad torque >> wrench??? >> > > > > >> > > > > Once that's corrected, there are many possible causes of >> vibration. >> > > > > How's your mag check? Any baffles, exhaust or intake parts >> touching the >> > > > > cowl? Broken valve springs? Bad lifters?.... >> > > > > >> > > > > -- >> > > > > John Cooper >> > > > > Skyport East >> > > > > www.skyportservices.net >> > > > > >> > > > >> > > >> > >> > > > > > ------------------------------------ > > Yahoo! Groups Links > > > >
