It would, indeed, be difficult to hand prop a plane with the prop at 2 & 8 or 1 & 7 (on a clock) as viewed from in front of the plane. As viewed from the cockpit this incorrect position would look like 10 & 4 or 11 & 5.
Kevin and Bob are correct in the 10 & 4 position when standing in front of the plane "addressing" the prop. WRB -- On Aug 17, 2010, at 10:08, Andy Anderson wrote: > 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 >> >> >> >> > > > > > ------------------------------------ > > Yahoo! Groups Links > > >
