Q - American Bonanza Society

the blades as possible. It is very easy to grind them so they willbe below minimum dimensions and the blades are thenunserviceable.HARTZELL PROPSIf your airplane is Hartzell-equipped. there are bladeclamp lubrication requirements that should be done at eachannual or every 100 hours. Be sure to use the grease the propshop used when the last overhaul was done and which shou ldbe listed in the propeller log.There should be placards on the blade clamps that say toremove one of the grease fittin gs (remove the inboard fitting).and pump the proper grease into the other filling until greaseflows out of the removed fitting hole. It is quite common tohave some oil leakage out of the outboard end of the bladeclamps. This is oil that was in the grease you pump into theclamps.The seal that is supposed to prevent this leakage is a beadof Permatex gasket compound (or equal) that is ap pliedbetween the shank of the blade and the clamp. Depending onthe ski ll and experience of the propeller mechanic, the blademayor may not leak at the outboard end of the clamp. With theengine turning at takeoff rpm, there is about 30 PSI hydrostaticpressure on this seal. Si nce there is no gasket or O-ringto make the joint leak-free, there needs to be a ce rtain amountof artistry involved in assembling the blade clamps to theblade.Another oil leak that may appear is one from the propellerpiston, or "dome" as it is more commonly called. Ahhough th isis a leak past tl,e O-ring seal, it may not be due to a faulty ring.There is a phenolic guide bushing that keeps the piston centeredon the cylinder and therefore also provides and controls the necessaryclearances so the O-ring will be able to seal. I have talkedto mechanics in Hartze ll -approved propeller shops who havenever measured this bushing to see if it wi ll provide therequi red piston-centering function. but would simply keepreplacing O-rings in an effort to stop a piston leak.If the surface of the cylinder is smooth and leaks continueto plague the installation, measure the inside diameter ofthe bushing, and if there is more than .003 clearance. the problemis most likely being caused by too much slop in the bushingfit. These bushings are replaceable.The oi l transfer unit (OTV) nose seal can also cause an oilleak. Some time ago, Hartzell changed the req ui rement of theseal installation fro m two seals to one seal. This was a changefor the better, since the use of two seals may actually cause thestart of an oil leak. The next time you have an OTU nose sealleak, make sure the mechanic doing the seal repair has a copyof the Hartzell service letter detailing this change.Another very common error mechanics make installingthe Hartzell propeller. as opposed to the Beech prop. is usingthe listed propeller retention nut torque for the Beech prop(400 foot/pounds) for installation of the Hartzell prop. Themaximum torque for the Hartze ll prop is 300 foot/pounds. If400 pounds is used, the OTU slip ring assembly WILL FAIL.causing a multitude of serious (costly) engine and propellerproblems.If control problems arise with a Hartze ll insta llation, donot allow your mechanic to attempt a fix unless he/she hasexperience wi th a Hartzell insta llation on an E engine. This isa different animal than any other engine/prop installation.The November 2000 ABS Magazine, page 6489, has alengthy article detailing the complete troubleshooting of theHartzell installation on an E engine. Hartzell has in print amanu al for the troubl eshooting of thi s installation.Unfortunately. it is sadly lacking in detail and completelyomits several important test steps that should or will pi n downthe problem.Many mechanics simply start changing components orsending off governors. T-drives, OTUs, etc. without testing tofind the trouble SpOI. I have heard of numerous times when itcost the aircraft owner several thousand dollars to fi nd a nickel'sworth of problem'ENGINE MOUNTSMoving a little fart her aft, we come to the engine mounts.They should be rotated 180 degrees at each annual. regardlessof the number of hours flown between annuals. Simply paint ayellow or white stripe across the mount rubbers on the outboardside. Loosen the mount through-bah about three turnsand then rotate the mounts so the paint stripe is on the inboardside. Usually the mount can be rotated by hand effort alone.The left rear mount is sort of hard to get to and mayrequire the use of water pump type pliers to rotate. Be carefulnot to skin up the involved parts using the pliers. I am able torotate all four mounts on my airplane in less than one hour.If your mounts have not been rotated on a regular basis,they may be sagged off center to the point where you mayhave to take the weight of the engine off the mounts to rotatethem. or new mountS may be in order. For those airplanes thatoriginall y had a 185- 1 or a 185-8 engine that has been convertedto a 185-11 or 225-8, be aware that the mount rubbersare different between the engi nes if a complete conversion ofthe original engine was done or if a different engine was usedfor tbe conversion.The earlier engi nes use a rubber mount with a cone shapeto the side that makes up to the engine mount leg (the piecebolted to the crankcase). The 185- 11 and the 225-8 engines.however, use an engine mount leg that does not have the coneshape, and therefore uses a rubber that is flat on both sides.When ordering Lord Mounts, remember that the engine modelshould be the QoverninQ factor, /l ot the aircraft model.If the mo~nt s are ~ot rotated and allowed to sag, as theywill do. serious engine and airframe structural problems willresuh.