October 2005 - American Bonanza Society

HARTZELL PROP &E-SERIES ENGINESAlthough I have published the diagnostic procedurefor determining the root of a problem witha dome-type, governed Hartzell propeller installedon an E-series engine in prior issues of the ABSMagazine, here's another go at it in this missive.I am quite amazed at the number of our memberswho do not have the back issues of the magazineor the CD-ROM to refer to when encounteringa problem with this system.This article will or should take one through the process ofpmnll1g down a problem in this prop system. However,one should also obtain and read a previous article on thesame subject which begins on page 6489 in the November2000 ABS Magazine and a related article that followed in theDecember issue. Perhaps the slightly different phraseologyused in the earlier articles would clarify, to some, informationin this article.This propeller and the necessary accessories needed tomake it work properly are really a very simple and cleverdesign. Hanzell has managed to fit a hydraulically controlledpropeller to an engine that was never intended to operate withthat sort of a system.However, it does require that all the components be inproper condition, and the engine modified as per Hartzelldrawings and instructions. If those conditions are met, the systemoperates exactly as we would like it to. That is, we are ableto get full takeoff rpm at any time; the selected governed rpmremains steady at any selected allowable setting; the oi l transferunit (OTU) does not leak an oil spray onto the windshieldin flight; and we are not paying some mechanic not familiarwith the system to "shotgun" the fix , if a fix is needed.For the above to happen, the owner of the airplane (that isyou, friend) must know at least the basics and, better yet, theintricacies of this installation. It is not that one needs to knowhow to overhaul the governor, but one needs to be able todetermine if the governor needs overhaul or bench-checking.The same goes for the oro and the T-drive.There is a test of the equipmelll that //lay be dOlle for eachmalady that confrollIs the mechanic attempting to find thesouree of the problem.Find source of problemThere are a number of situations that may cause a problem.But hopefully the cause of the problem is simply that theparts have served enough time and given enough trouble-freeservice that they are just plain worn out.Another is that one component has been removed, possiblysome repair work done on it, reinstalled and now the systemdoes not work as intended. Or the engine and all the accessories,prop system and everything else were overhauled andnow the system does not perform correctly.TestingIn any case, to pin down the problem, the troubleshooter onthe project must do a test or two. Most mechanics will simplysay, "It's the governor. We should send it off for a bench checkor overhauL" That may well be, but if the tests are not done, itwould be pure luck if the problem were fixed by that method.Before and during any testing, one needs to determine thatseveral conditions are met, per the Hartzell installation instructionsas detailed below. All of these would need to be done onlyon a newly overhauled engine or an engille that has had someamount of repair 1V0rk dOlle, or one that is being convertedfrom the Beech 215 prop to the Hartzell system. If the propellerhas been operating normally and a problem shows up afterwork is done on only some component of the propeller-andno work has been done on the engine-the fo llowing itemswill not be a factor, or rather, they should not be a factor.OK. here we gO ...Determine that the normal crankshaft seal (normallyinstalled at the front end of the engine) is not installed. On theBonanza "dry sump engines," this seal is now at the front endof the OTU. (Per Hanzell Service Letter, there should only beone seal installed, not two as was done in the past years.)If this normal crankcase seal is left in place, the OTUhousing will be pressurized to 225 psi and may force the sealin the fro nt of the housing out of the housing, causing rapidloss of all the engine oil.Determine that the shaft seal normally installed in thelower left accessory drive shaftgear adapter (where the T-driveis mounted) is not installed. This seal is now installed at therear of the T-drive where the fuel pump is now mounted.Determine that if a repair bearing bushing has beeninstalled at the front end of the lower left accessory shaftgear (thebushing is a press fit into the front wall of the accessory case), anannulus groove has been provided in the bushing so adequate oilsupply is fed to the governor through the shaftgear.The original bearing at this location was machined in themagnesium accessory case and an annulus groove was provided