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April 1993 - American Bonanza Society

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lock in place to protect the control<br />

sutfaces from ever-present dangers.<br />

Since I've been unable to find<br />

good inf0n11ation on this matter, J did<br />

my own Iitlle test during the last annual.<br />

\Vith the aircraft on jacks, the<br />

nose w heel was rotated with the gust<br />

lock bOlh in and out. We could neither<br />

feel nor measure any Significant<br />

difference in the fo rce required to<br />

turn the nose w heel. This suggests<br />

that towing the ai rcraft (which<br />

requires turning [he nose wheel) with<br />

the gust lock installed poses no threat<br />

to control linkages.<br />

Second. I've had knowledgeable<br />

old ABS salts tell me that when my<br />

gas gaps (Shaw Aero type) start closing<br />

hard and little cracks show upon<br />

the large O-rings, that it's time [Q<br />

replace the rings. I have found, however,<br />

tha( even new rings treated with<br />

Parker Iiale O-ring Lube show cracking<br />

in a very short time and that caps<br />

close ha rd because the earning<br />

surfaces are galled, or more commonly,<br />

lack lubrication.<br />

A drop o r two of silicone, or a dab<br />

of O-ring lube on the bearing surface<br />

where the gas cap lever rides against<br />

the top of the cap housing will work<br />

wonders. In fact, without some small<br />

lubrication here, it can be very difficult<br />

to close the caps or check for proper<br />

adjllSUTIent of the cap. On more than<br />

one occasion. I've seen ov,TJlers putting<br />

the muscle to caps to close them. This<br />

can lead to galling and is easily solved<br />

by a drop of lube. - Robert Can· , ABS<br />

19257, East lansing, Mich.<br />

Checking belt tension. In the December<br />

1992 issue, both Noml Colvin and<br />

Lew Gage had some conunems on<br />

checking belt tension on those engines<br />

that have belt driven genera(Qrs or<br />

alternators. I would like to add my two<br />

cents worth. In these inflationary times,<br />

it may even be worth four cenrs.<br />

EveI)' so often, it is worthwhile to<br />

pay atte ntion to what your enenlies are<br />

saying. In this case, the enemy is<br />

Lycoming. Lycoming Service Instruction<br />

' 0. 1129A describes an extremely<br />

easy, neat and reliable method for<br />

checking belt tension.<br />

You simply use a torque wrench<br />

and derennine the torque necessary to<br />

make the genermor or alternator pulley<br />

slip against the belt. Since l ycoming<br />

did not take the trouble to copyright<br />

the ir service instruction, I shall quote it<br />

directly.<br />

a. Apply a lOrque indicating wrench<br />

lO the nut that anaches the pulley to the<br />

generalOf and tum it in a clockwise direction.<br />

Observe the torque shown on<br />

the wrench at the instant the pulley<br />

slips.<br />

b. Check the torque indicated in step<br />

(a) with torque specified in the follow~<br />

ing chan. Adjust belt tension accordingly.<br />

Torque indicJted<br />

at generator<br />

Width of Belt Condition pulley<br />

3/ 8 inch New 11 to 13 ft.lbs.<br />

3/ 8 inch Used 7 to 9 rUbs.<br />

1/2 inch New 13 to 15 ft.lbs.<br />

1/2 inch Used 9 (0 11 ft.lbs.<br />

Note: The higher tension specified for<br />

a new belt is to compensate fo r the inilial<br />

stretch 1hm takes place as soon as it<br />

is operated. These higher (cnsion va l­<br />

LIes should not be applied LO belts<br />

which have been used preViously. Although<br />

the specified torque values for<br />

DC generators and alre mators are the<br />

same, the tension for alternator belts<br />

should be slighlly higher than the tension<br />

applied [0 DC gener-dtor belts.<br />

Also, Chrysler alternators do not have a<br />

nut on the shaft and therefore cannol<br />

be checked by this method.<br />

If you do not have a torque wrench,<br />

you can buy one at Sears or K-Mart for<br />

about $8-far less than it would cost to<br />

have an A&P dleck the belt tension.<br />

You w ill also need a ' y" socket for the<br />

generator nul. I do not know what size<br />

nurs are used on alte rnators (other<br />

than Chrysle r), probably the same.<br />

Lycoming fa ils to mention that you<br />

do have to hold the prop from turning<br />

while you are checking the belt tension.<br />

Also, the belt manufacturers have<br />

recently gone meLric. The three-eighths<br />

inch w ide belts, which I think are used<br />

by all Continentals, are now shown as<br />

8 mm. -Chet Steele, ABS 22902, San<br />

Antonio, Texas.<br />

Baron alternator problems. We had a<br />

problem with both alternator waming<br />

lights coming on at various timestaxiing<br />

out, afte r takeoff, in cmise<br />

night, in the landing configuration. It<br />

did not appear to be in conjunction<br />

with the operation of any avionics<br />

component or system. It seemed they<br />

would always kick out when your attcntion<br />

was on some mooe of flighttaxiing,<br />

takeoff, landing-never when<br />

you were looking at the load meters.<br />

Our local Beech shop loaned us<br />

their digital voltmeter that hooked up<br />

to the lighter socket. We operated d,e<br />

plane o n the ground. cutting on and<br />

off all lights and avionics. We duplicated<br />

a kickoff when we shut off tl,e<br />

landing lights. Volts went to 32 o r 33<br />

volts, the n kickoul. This tells us the<br />

over voltage protection is doing its<br />

thing. $0 now we h~lve a spike that is<br />

kicking dle alternator off line. Is d,e<br />

spike coming from taxiing out, taking<br />

off, cruise or landing?<br />

We decided to try and pinpoint the<br />

problem operation on one alternator<br />

or one voltage regulawr. \Vle flew in<br />

the pattern with all combinations of<br />

voltage regulator and alternator. It<br />

kicked off once-when we were in<br />

cruise and low power settings looking<br />

out the window for traffic. This was all<br />

done with the digital voltmete r in<br />

place. The load meters showed any<br />

combination of alternator and voltage<br />

regulator carried the load fine-except<br />

when it kicked out, we were on vohage<br />

regulator ':1, right alternator.<br />

I wrote Norm about our problem.<br />

He suggested changing a voltage regulator.<br />

Again, to me, dle voltage regulators<br />

were doing their thing~ver voltage<br />

trip when we get over voltage spikes.<br />

We talked to our local avionics<br />

shop to see if they had any ideas on<br />

which avionics component would<br />

cause a voltage spike. They felt it was<br />

alternator caused.<br />

We talked to John Evans of<br />

Aerotech very ncar LOU (Bowman<br />

Field , Louisville, Ky. ). John suggested<br />

stopping in when down (hat way to<br />

see w hat we could figu re o u t. \Ve<br />

scheduled a visit.<br />

On the way to LO U, they kicked<br />

alit five times-four in flight at cruise,<br />

once on fmai.<br />

On arrival, we contaaed Rich<br />

Coover, service manager for Kennlcky<br />

Flying Service (KFS). Rich wanted to<br />

run up the plane whUe it was still hot<br />

from the flight. We could not get anything<br />

to kick out. His opinion \vas that<br />

it was O.K. Of course, we knew bener.<br />

Next morning, both alternators<br />

were removed and Aerotech picked<br />

AMERICAN BONANZA SOCIETY, APRIL <strong>1993</strong><br />

PAGE 3208

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