PS Magazine Issue 134 1963 Series [134 ed.]

Citation preview

THE

PREVENTIVE MAINTENANCE MONTHLY

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The people who put out the telephone directories for the posts, camps lind stations have been doing some mighty

post directory , where more than likely you' ll find the post maintenance activities lumped together under a generlll term such as " Consolidated Field M(lintenance" or "Combined Field Maintenance,"

lind further broken down under such functional sections as Armament, Tracked Vehicles, Wheel Vehicles , General Purpose, Avionics, Electronics, Aircraft and such, instead of

and when you start looking real close you mllY discover that a number of these functioned sections have the same building number or address,

which should send shivers of gladness through your heart since tl~re' s nothing more convenient than having a one-building or one-area service center where your tank, for example, cun get its engine, guns, radio, searchlight and filter unit, gas particulate, up-snuffed .pretty much in one fell swoop instead I of having to be shuttled around from one specialty shop to another at a considerable waste of time and effort,

gee, the authority and responsibility for combining

and consolidating these important mllintenance functions doesn't generally rest on the shoulders of people who compile telephone

so you start looking further and sure enough, you sUlrt running across such titles as "Director of Field Maintenance," and "Superintendent 0/ Field

and CO's for some strange reason take a mighty dim view of being

·'surrounded."

longer seems to be any doubt as to "who's in charge here,"

JV ell, any ol' how, the more you study the directory the more intriguing it becomes and

it

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conduct his maintenance business since he always felt that under the old system he wasn't being "supported" so much by maintenance as he was "surrounded" by it,

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TIME FOR

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Dear Half-Mast, This ain't Ileggs_ackly" like the chicken and the hen/ruit hex, Sarge, bitt when you get the march order for your towed l05-mm howitzer which should you do fwst-put the cradle lock strut in place like FM says or should YOII first close the locking trails, traveling lock piece and traveling lock loop like TM 9-325 spells out? ll7e got a h~sle going on this. Sgt. J. J. D.

6-75

make adjustments on

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And- last- push the cradle strut down. But do it easy. If it slides in place with no sweat, fin e, great. This means all's well with the world. But if it won't slide easy, now's the time to take an extra minute to double check and fix. If it's off in traverse, the travel lock brackets need adjusting . .. If it's off in elevation, the cradle strut

Dear Sergeant J. J. D., Max nix, actually. Although the apparent contradiction in the two pubs makes' it look like somebody's laid an omelet, you'll get about the same results no matter which' way you do it. However, I like the TM's way better because it gives you more chance to the Strut if

they're needed. Look at it this way-if you do it the FM's way and lock the cradle locking strut first you .rpay save time for a hot date hut only if everything's adjusted right. If even one lock's out of line though, and some hefty cannonee; should try to force a fit, your gonna howl.

After you bring the trails almost together, work the elevating handwheels to lir,e up the cradle locking shoff piece with the crodle traveling . lock brackets. Then close and lock the trails, the travel locking piece Dnd trovel locking loop. 16

To odjust the traveling lock brockets, first loosen the capscrews holding the brackets to the roils. Next, tighten or loosen the adjusting nut till the socket and the ball-shaped end pieces line up even. Then re·tighten the setscrews.

To work on the cradle lock strut-whether it's too long or too short-loosen the iam nuts on the strut and turn the turnbuckle till you get the exact length you need. Then re-tighten the jam nuts. There, now you're ready to hit the road. 17

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with no sweat, fin e, great. This means a ll's well with the world. But if it won't slide easy, now's the time to take an extra minute to double check and fix. If it's off in traverse, the travel lock brackets need adjusting ... If it's off in elevation, the cradle

To adjust the traveling lock brackets, first loosen the copscrews holding the brockets to the roils. Next, lighten or loosen the ad· justing nul till the socket and the ball-shaped end pieces line up even. Then re-tighten the setscrews.

To work on the cradle lock strut-whether it's faa long or too short-loosen the jam nuts on the strut and turn the turnbuckle fill you get the exact length you need. Then re-tighten the jam nuts. There, now you're ready to hit the road. 17

EASY DOES IT - LIKE ALWAYS

Easy does it if you want to keep tabs on your M73 machine gun.

These twO tabs on the rear of the receiver are the seating surfaces for the backplate assembly. And these control the adjustment of the sear hooks. Now, if you get careless and bend these tabs, you'll change the adjustment. Bending the tabs upward , for instance, could cause failure to fire-if the sear hooks don't release the barrel extension when the trigger's pulled. On t'other hand, if you bend 'em downward by slamming the backplate in place, or any other way. you'll cause a "runaway" gun by letting the sear hooks go so far down that they won't catch the barrel extension when the trigger's released. 18

Your whirlybirdman just with this gripe: His M37C machine gun refused to accept a cease-fire order. It kept blazing away. What gives? Could be one or both of the cotter pins (MS-24665 _ .. FSN 5315-8151405) that secure the solenoid cap assemblies (8427806 ... FSN 1005-8041679) caused the ruckus.

cotter pins likely vibrated into a vertical position and lodged against the top of the solenoid. This'd keep the solenoid plunger from returning to its 19

original position after the solenoid was de-energized-and the gun kept chattering. The way to prevent this in the future is this: Clip off enough of the cotter pin so's only at most Ys inch sticks out beyond the cap when it's installed. And snug the ends of the pin tight around the cap.

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MAKES NO DIFFERENCE That's right. The nut that's used with a bolt to attach the center fin to the warhead section on your Nike-Hercules missile is supposed to be Y2 inch across the flats. But there was a slipup somewhere along the line, and nuts that're ¥s inch across the flats were packaged under the FSN (5310-535-8668) that goes with the nuts with the Y2 -in flats. Go ahead and use the smaller nut. Both have a 5/16-24 UNF-3B thread ... and that's the important thing.

BEFORE MWO 9-1440-252-30 10

20

80TH HAVE 5/ 16-24 UNF-38 THREAD

a~ 'fa SO .. . OK TO USE SMAUER NUT

DOING THE You might be doing the twist when you go to move the electrical cables on the power receptacle to the dummy receptacle and back again on your Nike-Hercules launcher. If you're having a twisting problem with the cables, the chances are that your support unit hasn't been around to apply MWO 9-1440252-30110 (22 Mar 62) to the launching-handling rail. The MWO changes (he dummy recep(acle disconnec( lever co a new configuration to cut down on the chances of the lever getting damaged. Dummy receptacles had been in

LUBE OR NOT?

r--=-------,

MAKES NO DIFFERENCE That's right. The nut that's used with a bolt to attach the center fin to the warhead section on your Nike-Hercules missile is supposed to be Y2 inch across the flats. But there was a slipup somewhere along the line , and nuts that're ¥s inch across the flats were packaged under the FSN (5310- 5 3 5 -8668) that goes with the nuts with the Y2 -in flats. Go ahead and use the smaller nut. Both have a 5/16-24 UNF-3B thread . . . and that's the important thing.

BEFORE MWO 9-1440-252-30 10

20

80TH HAVE 5/ 16-24 UNF-38 THREAD

a~ 'fO SO . .. OK TO USE SMAllER NUT

Dear Half-Mast, Tell me . .. do the waveguide shutters in our Nike-Hercules track radars get lubed? I've heard arguments that they do and illSt as strong arguments that they don't. Sgt D. T. Dear Sergeant D. T., No-that's spelled N-O - the shutters don't get lubed. That is, firing batteries don't lube them . And your support unit has a publication on maintenance of the waveguide shutter assemblies (TB Ord 1430-34/1) that says the shutters are hit with molybdenum disulphide by the manufacturer and shouldn't need any more of the stuff for the life of the assembly. t..=====~"'::~~::::::::~J Of course, if the shutters in your radars act stubborn when it comes to opening and closing. it's time to buzz your support people for a helping hand.

1I1l/{H/04t DOING THE You might be doing the twist when you go to move the electrical cables on the power receptacle to the dummy receptacle and back again on your Nike-Hercules launcher. If you're having a twisting problem with the cables, the chances arc that your support unit hasn't been around to apply MWO 9-1440252-30/10 (22 Mar 62) to the launching-handling rail. The MWO changes the dummy receptacle disconnect lever to a new configuration to cut down on the chances of the lever getting damaged. Dummy receptacles had been in

TWIST?

AFTER MWO 9-1440-252-30 10

a position where you didn't have to twist the cables to get them in the shells. But MWO Ord Y86-W12 (2 Nov 59) came along and turned 'em around 180 degrees to keep the lever assembly from getting battered. MW09-1440-252-30/ 10 puts things right back where thcy were before MWO Y86-W12 came out 'cause there's a notc in the latest MWO that says the receptacles shou ld be reversed, in other words. be put in the position they were in before M\VO Y86-W12 was applied. Once this is done, you won't have to swea t out the twisting causing the insulation on the cables to split away. and make things ripe for a short. 21

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LUBE OR NOT?

Dear Half-Mast, (""",=---"",="""---, Tell me ... do the waveguide shutters in our Nike-Hercules track radars get lubed? I've heard arguments that they do and just as strong arguments that they don't.

S9t D. T. Dear Sergeant D. T., No - that's spelled N-O - the shutcers don't get lubed. That is, firing batceries don't lube them. And your sUPPOI'[ unit has a publication on maintenance of the waveguide shuaer assemblies (TB Ord 1430-34/1) that says the shutters are hit with molybdenum disulphide by the manufacturer and shouldn't need any more of the stuff for the life of the assembly. L.::====~...::~~c:::::.:"-J Of course, if the shutters in your radars act stubborn when it comes to opening and closing, it's time co buzz your support people for a helping hand.

lIo/{ff/fJ4I TWIST?

AFTER MWO 9·1440·252·30 10

a position where you didn't have to twist the cables to get them in the shells. But MWO Ord Y86·W12 (2 Nov 59) came along and turned 'em around 180 degrees to keep the lever assembly from getting battered. MW09·1440.252·30!lOputs things right back where they were before MWOY86-W12 came Out 'cause there's a note in the latest MWO that says the receptacles should be reversed, in other words, be put in the position they were in before MWO Y86-W12 was applied. Once this is done, you won't have to sweat out the twisting causing the insulation on the cables to split away. and make things ripe for a short. 21

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"Hands Off." And in letters maybe one foot high. That's the kind of sign that oughta be hanging from the bracket that holds the umbilical plug on the Hawk missile. It can be done, tho, so you and all the other people in your outfit have to remember nOt to mess around 'with the cap parr of the bracker-like taking it off. The cap and the rest of the bracket are machine-matched around the piug

and should stay where they are-unless some guy in a higher echelon has to rake them off. And it wouldn't hurt any to pass along a hint to the guys up the maintenance line---Qne rhey can use to make sure the cap and the rest of the bracket stay with the same missile whenever the cap is taken off. Sort of suggest that they tie the cap and bracket together with a piece of wire. Then when they reassem~ bie things, the plug will be sure to fit. 22

Dear Mister W. G ., You use the lot number on the igniter in the serial 'l/":!I!';!,_.... number column on the 2408-10. That's right-the lot number. With the igniter, and many other ammo items, one lot number includes different serial numbers. So . . . if you have to suspend a certain lot of NO INITIATOR igniters for any reason, the lot number identification INfORMATION turns out to be the best way of doing it. I As for the initiator ... you' re right about it not having a serial number. Those four digits a re the manufactu rer's number and are the same on all initiators. And there's no req uirement for putting initiator information on the 240S-IO

liol!_»!fJ4i;

" Hands Off." And in letters maybe one foot high. That's the kind of sign that oughta be hanging from the bracket that holds the umbilical plug on the Hawk missile. It can be done, tho, so you and all the other people in your outfit have to remember not to mess around 'with the cap part of the bracket-like taking it off. The cap and the rest of the bracket arc machine-matched around the plug

and should stay where they are--unless some guy in a higher echelon has to take them off. And it wouldn't hurt any to pass along a him to the guys up the maintenance line--one they can use to make sure the cap and the rest of the bracket stay with the same missile whenever the cap is taken off. Sort of suggest that they tie the cap and bracket together with a piece of wire. Then when they reassem~ ble things, the plug will be sure t6 fit. 22

So your support unit came along and applied MWO 9-1440-500-30/6 to your Hawk pallet. And now you don't have to sweat out whether the missiles are held in place when you tow the pallet with the birds on it. You know they are. Trouble is, tho, the MWO brought a slight problem with it-getting hold of an extra plug or two. You know the one ... it screws into the stud for the missile anchoring assembly--one of the things put on the pallet by the MWO. Now and again, a plug turns

up missing ... and you haven't been able to get any replacements. But that was before your support unit was issued TM 9-1440-500-35P/2 (Mar 63). The plug is listed on page 241 . . . and under OPN 10065570. When you ask your support people to requisition some of the plugs, you might tell 'em the FSN for the plug is 5340-530-5542. If you wam to keep dirt and water out of the stud while you're waiting for some replacement plugs, try putting some tape over the top of the stud.

I

NUMBERS

Dear Mister W. G., You use the lot number on the igniter in the serial number column on the 2408-10. That's right-the

lot number. With the igniter. and many other ammo items, one lot number includes different serial numbers. So . . . if you have to suspend a certain lot of NO INITIATOR igniters for any reason, the lot number identification INFORMATION turns o ut to be the best way of doing it. REQUIRED As for the initiator ... you're right about it not ON 2408·10 having a serial number. Those four digits are the

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manufacturer's number and are the same on all initiators. And there's ~o requirement for putting

initiator information on the

240S-IOj;oI!_Jl/fJ41

So your support unit came along and up missing ... and you haven't been applied MWO 9-1440-500-30/6 to able to get any replacements. your Hawk pallet. And now you don't But that was before your support have to sweat out whether the missiles unit was issued TM 9·1440·500·35P/2 are held in place when you tow the (Mar 63). The plug is listed on page pallet with the birds on it. You know 241 . . . and unde, OPN 10065570. they are. When you ask your support people to Trouble is, tho, the MWO brought requisition some of the plugs, you a slight problem with it-getting hold might tell 'em the FSN for the plug is of an extra plug or two. You know 5340-530-5542. the one ... it screws into the stud for If you want to keep dirt and water the missile anchoring assembly--one out of the stud while you're waiting for of the things put on the pallet by the some replacement plugs, try putting MWO. Now and again, a plug turns some tape over the top of the stud.

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NO FITTING, NO . LUBE Those M514, M545 and M390 trail· ers that'ce used as chassis for various pieces of Hawk equipment-like the pallet, radar sets and missile test shop -suee do look alike. So it was no wonder that a guy use to flip his lid when he looked at La 9·2330·236·10 (Apr 60) and wondered how in blue blazes he was supposed to lube the hand brake cables on the M514 and M54S ... when, no matter what the LO said, there are no grease fittings to lube on the cables. _ _----J---::::~=---~-

cables for both of these trailers have grease prepacked in their assemblies and get no lubing.

La 9·2330·236·12 (1 4 Jun 63) cor· rects the booboo and eliminates the requirement for greasing the M51 4 and

M545 brake cables. You want to keep lubing the M390 brake cables, tho--with GAA and quarterly. 24

If you're around to make a report of survey. here's one way to get him to your Hawk outfit . .. and doing double-time. Before you go to raise the boom support, forget to release one or two of the turret latches on your Hawk launcher.

You'll wind up with a nice batch of damage-like a busted ring assembly.

r-- - - -- - - - -""D=d

You might also bend the chassis that ":::~~r::~;;:;~li~~ the ring assembly sits 00. IOf course, if you don't want to see

dollar signs in your sleep, you'll make sure the latches-all eight of •em-are down before you start raising the boom III!!I!!!!~~L~~::JL~_:":::J

support.

Real handy. But using the power and data cables on your Hawk CW acq and illuminator

radars as steps also adds up to a bad situation. Why ? You can bust the cable coo-

nector and snap the wiring inside the cables. And broken wires lead to shorts. That's why. So side-step those "steps" whenever you have to climb up on the radars. It might take an extra grunt to make the short climb, but look at what you get as a bonus-Po T. 25

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YOU'RE COVERED ..• BUTlike reference you can check para 7, AR 735-35. Di((o pam 9b(2). But, remember-don't ever let this supply tcuth go to your head. You'd best do everything possible to keep your stock of repair parts what it should be ... 'cause it takes repair parts O/H to keep you moving, shooting and communicating. Duc-outs won't get a dead lined vehicle or weapon or radio to the fight,

Stow the alibis, sad tales, excuses. A legit due-out, or a request on·theway. is all the inspection-proof you need ro show the man that your load of Hmust-be-stocked" repair parts is what it should be. Yep, D/O's and current requests for those items are just like items in the bin-when you're counting noses, like at inspection time. If you need a quick-

THAT'LL COST Y A •.• To your list of need-to-know supply

pubs you can add TB 9-30 (29 Mac 63) "Standard CONUS Maintenance Costs for Ordnance Type End Items." It sets up standard maintenance and repair costs for selected items of equipment ranging from small arms to wreckers. It's useful for figuring an item's worth for reports of survey and estimating equipment upkeep for other kinds of records and reports. 26

TIRE SCOREBOARD ~

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Dear Half-Mast, Witt you please clarify the confusion that has spr#ng liP /1'Om the lISe af VA Form 240B-3 and -3-1 (Equipment Organizational Maintenallce Record), Do we post tire and tube replacements (new or used), flats , flaps, valve caps, valve cores and hot patches? SFC C. A. F.

f-I-'"

,.-1-.3

'.loltJ,phat(wdkP"""", '3

~qJo '(j91-~'"

'7401~ - ~

Dear Sergeant C. A. F., The answer to this is in paragraph 43b(I2), page 71 of Change 1 (Mar 63) to TM 38-750; it specifies that common hardware items such as nuts, bolts, screws, cotter pins, tubing, etc" are not to be entered on the 2408-3 or -3-t. Fixing flats with hot patches, replacementS of flaps, valve caps and valve cores comes under the heading of com-

I€T,R.w..ztU

#g ,/3d{!

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moo hardware and are not entered on the 2408-3 and -3-l. Tires and tubes are a different subjeer. These items have a dirccr bearing on the over-all cost and maintenance history of the vehicle, so you want to make sure they get posted on the Equipment Organizational Maintenance Record (DA Form 2408-3 or -3-1). 27

Halrff/Mt

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Dear Half-Mast, I keep getting static (from a neighbor) on my interpretation of para 13b(3), AR 735-35, and of the hand receipt annex info on page 9, P5 118. 50 please correct me if I'm off the beam. I say that: 1. We no longer keep a hand receipt annex (DA Form 2062) itemizing all components of sets, kits, chests and olltfits. 2. The annex is prepared only when components (of sets, kits, etc.) are short or over. 3. The supply manllal covering the end item is noted on the hand receipt and used for inventory info. Well, Sarge? CWO F. E. P.

Dear Mister F. E. P. , Drown the static. You're right. Note also that the AR's Change 1, para 13b(3) says that the word balance will be lined out on a hand receipt annex, and the quantities short or over recorded in the numbered columns. Fig 3, page 6, of Change 1, shows a sample H/R annex. 28

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loES Dope Sheet

IF YOU WANT TO DISPLAY THIS CENTERPIECE ON YOUR BUl

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lo£S Dope Sheet

Combat-read4 equipment's the stuff: It will keep 40ur outfit up to snuff. For fighting be read4, Trim, willing and stead4·

~ An'

the aggressor will alwa4s find 40u tough.

IF YOU WANT TO DISPLAY THIS CENTERPIECE ON YOUR BULLETIN BOARD, OPEN STAPLES, LIFT IT

our AND PIN IT UP.

combat-read4 equipment's the stuff: It will keep 40ur outfit up to snuff. For fighting be read4, Trim, willing and stead4· the aggressor will alwa4s find 40u tough.

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We were really on the go for a while, trying to take the hydromechanical dutch screen out of our Mojave (CH-37) on an intermediate inspection, as called out on page 841 of Change 1 (21 Mar 62) to the basic TM 55-1520203-20. We searched high and low (without any luck) for a wrench big enough to break the 2-in oil hose connection at the pump, in order to get the screen out. The largest wrench in the organizational "C" tool set only goes to 1 ~ -in, so we made up this handy 2-in open-end wrench to do the job, The wrench head is made from 3/16-in flat steel, SAE 4130, and the hex handle from Y2-in steel. We cut a slot in the handle to hold the head, and welded both pieces together. Now we have a genuine wrench that works real fine in breaking the hose

(Ed Note-Good going, No doubt the wrench also comes in handy at olhel' places on your bird!) 37

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PRE-OIL YOUR CHOCTAW (CH-34) ENGINE TO KEEP_TH_E_"_AI_R_YIlLA_IN_"__"_"_ _ _ _::!~

A~ fJ2 ~

~~~ Whoever said what you can't see won't hurt you never spent any time around a bird engine, that's for sure! Otherwise he would have realized that an cngine may be accidentally cranked up on a dry maSter rod bearing. So how docs a bearing get dry in the

first place? \Vell, the forces of gravity being what they are, oil just naturally drains off bearings and other vital engine parts. And there's just about noth. ing that'll cause an engine to fold up faster'n running it without oil. That's why pre-oiling is mighty important. Take the R-1820-84A or 84C engine in rour Choctaw (CH-34), You want to make with the pre-oiler: Before starting a new, or newly over· hauled engine for the first time; Before starting an engine that hasn't been run for -72 hours; After an oil change; Whenever oil drains from the oil inlet line; Or if you suspect that air has gotten into the line. Air in the oil inlet line is the real villain of this story. It can find its way into the oil pump _and block the passages. Even after cranking an engine

over for several minutes- without preoiling-it'll refuse to move. The result is no oil pressure (and no oil) to the bearing. The best way to get rid of the "air villain" is to flood him out of the oil passages. This pre-oiling change to the TM 55-1520-202-20 maintenance pub is in the works to do just that.

HEAT THE OIL Move the pre-oiler to the bird and start 'er up.

Fill the bird's oil tank to the capacity given in 1M 55-1520-202-20 (20 Feb 62) . Wheel up an APU to give you a high engine cranking speed and reduce the strain on the starter.

38

A\ _

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PRE-OIL YOUR CHOCTAW (CH-34) ENGINE TO KEEP _TH_E_"_AI_R_YI_LLA_IN_"__'_' _ _ _ _:j~

~ iQ1T::r

A~ ~~ .~

~~~ Whoever said what you can't see won't hurt you never spen t any time around a bird engine, that's for sure! Otherwise he would have realized that an cngine may be accidentally cranked up on a dry maSter rod bearing. So how docs a bearing get dry in the first place? \Vell, the forces of gravity being what they are, oil just naturally

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over for several minutes- without preoiling-it'll refuse to move. The result is no oil pressure (and no oil) to the bearing. The best way to get rid of the "air villain" is to flood him out of the oil passages. This pre-oiling change to the TM 55-1520-202-20 maintenance pub is in the works to do jusc chat.

drains off bearings and other vital en-

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Latch on to some drain pails to take care of the oil flow and you're 'bout ready for action. Disconnect the spark plug lead and take out a plug from each cylinder to get rid of the compression. 'Tis a mighty important step because you want a high cranking speed. This will give you the pressure needed to push the oil to those dry bearings.

That's why if you have a low cranking speed, or even if the engine doesn't start in a reasonable time, you wanc to eye the front sump for a possible overflow and drain off any excess oil.

Next, place the pails under the magnetic drain plugs-and toke out the plug at the front sump and at the supercharger rear housing.

HEAT THE OIL

gine parts. And there's just about noth. ing that'll cause an cngine to fold up faster'n running it without oil. That's why pre-oiling is mighty important. Take the R-1820-84A or 84C engine in rour Choctaw (CH-34), You want to make with the pre-oiler:

Move the pre-oiler to the bird and start 'er up.

Before starting a new, or newly overhauled engine for the first time; Before starting an engine that hasn't been run for -72 hours; After an oil change; \Vhenever oil drains f rom the oil inlet line; Or if you suspect that air has gotten into the line. Air in the oil inlet line is the real villain of this story. Ie can find its way into the oil p u mp .and block the passages. Even after cranking an engine

If you're pre-oiling 0 new engine, or a newly

Fill the bird's oil tank to the capacity given in TM 55- 1520-202-20 (20 Feb 62),

Wheel up an APU to g ive you a high engine cranking speed and reduce the scrain on the starter.

38

overhauled engine, you also want to take out oiling can overflow the front sump the oil inlet strainer, cleDn it, and put it bock with oil, giving you a partial or full in before you go any further,,'--r:77.".......' " hydraulic lock in the lower jugs. This is caused by the smaller return capacity 1L-l1!'!!J'~~'f'"l:li of the scavenge pump when operating at too Iowa speed.

latch on to some drain pails to take care of the oil flow and you're 'bout ready lor adion. Disconnect the spark plug lead and take out a plug from each cylinder to get rid 01 the compression. 'Tis a mighty important step because you wont a high cranking speed. This will give you the pressure needed to push the oil to those dry bearings.

Keep in m ind that a low cranking speed and a delayed start after preoi li ng can overflow the f ront sump with oil, g iving you a partia l or fu ll hydraulic lock in the lower jugs. This is caused by the smaller return capacity of the scavenge pump when operating at too Iowa speed.

T hat's why if you have a low cranking speed, or even if the eng ine doesn't start in a reasonable time, you want to eye the front sump fo r a possible overflow and drain off any excess oil.

Next, place the pails under the magnetic drain plugs-and take out the plug at the front sump and at the supercharger rear

If you 're pre·oiling a new engine, ora newly overhauled engine, you also want to take out the oil inlet strainer, denn it, and put it back in before you go any:...f~uT rth~en ' . ~~~~~

So far ... so good. Take five and try remember the last time you pre-oiled this baby! Did you get a quick reading on the oil pressure gage in the cockpit? If not, that old "air villain" may be in the line again. So you'll want to bleed and refill the line between the engine and the pressure gage with engine oil.

Keep pumping (he oil until two (0 three gallons have drained .from (he engine frone sump and you get a reading on (he oil pressure gage in the cockpit. Then shut off the pre-oiler and disconnect the pre-oiler line. But don't put the pre-oiling hole plug back just yet.

Next, (heck the chart in the pre-oiler to get the right size (onnection fiHing for the R1820 engine. The 1/4-in NPT fiHing is the boby you wont.

Take off (he ¥s-in cap at the "Y" drain fitting, and connect the pre-oiler. Plug in the APU.

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'" l~~~~~~~~~~~~~ PRE-Oil AT THE PUMP Take out the pre-oiling plug atthe oil pump, put in the %-in NPT fiHing, and conne~1the pre-oiler hose. (heck the temperature of the oil-it should be 160 to nO-degrees F-ond ... shoottheworks!

Start the pre-oiler and pump oil into the engine, at a temperature of 160 (0 220 degrees F, while at the same time cranking the engine over with the starter. (Of course you made sure that the ignition switch was off and the mixture control was in idle cut-off before that's Crank 'er over no longer than 20 or 30 seconds at a time, so the starter has a chance to cool off.

40

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stop hose, _take the T/.. _in NPT fiHing out, and put the engine plug back in right away ... that'll stop the ·'air villain" in his tracks!

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Meanwhile, the overflow oil from the plug hole in the sur.np and supercharger rear housing should have completed draining. So put the plugs back in the engine. Remember to follow the reassembly poop in your maintenance manual on all the parts you took off, including torque values and lock wiring instructions. 41

Dear Wi1JdYI IV'e have an aircraft in our outfit which has not had TM 1-1L-20A-I030 complied with. The modification reads as follows:

IV'hen to accomplish: As scheduled by fourth echelon maintenance activities or IIpon failure of the valve prese1Jtly i11Stalled in the aircraft bllt in 110 event later thanJO March 1963. The statement ltmderlined means to me that the modification will be complied with by that date or the aircraft is grounded. Am I right or wroug? Sp-5 W. P. W. Dear Specialist \Xf. P. \Xf., You're wrong! The aircraft goes on a red dash status as of 31 Mar 63 if the modification has not been applied. According to Para 57c (e) (3) on page 104 of TM 38-750 (May (2) you've got a "component replacement" due on that aircraft. which calls for a red horizontal dash on the DA Form 2408-13. You won't accomplish the purpose of the MWO by grounding that bird. because this makes it impossible to fly the aircraft over to 4th echelon for :M\.VO compliance. Between the continuing red dash on the aircraft's DA Form 2408-13 and the MW'O entry in the)eft hand portion of the aircraft's DA Form 2408-5, an incompleted MWO . . will stick out like a sore thumb the very next eM!.

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That's right! Thy maintenance will be done. This is the only way the Army can be sure all MWO's are applied within a reasonable period of time. Configuration control, they call it.

PICTURE YOUR GASKETS Dear Editor, Can't see ruining perfectly good gaskets by hanging 'em up like a tanned hide stuck on a peg in the woodshed. It dries 'em out and makes 'em hard to reshape afte r being exposed to the air. Here's part of a gasket board we made up for the mechanics to eyeball, with black outlines of the gaskets on a wh ite background. Since each FSN and bin location is lettered underneath the drawing, any body on duty in the tool room can hit the right drawer without any sweat. That way a11 our gaskets stay in the original packages until they're used. 55g! Edgar L. Lee Lawson AAC Fort Benning, Ga.

(Ed Note-That sllre is a shm'p 100ki1Jg board. But the one thing paint won't show is (he material used in manufacturing the gasket. IVith the cost of gaskets being pretty reasonable, might pay to Pllt liP the real thing in additiml to the paint job, Sarge.) 43

•

It wasn't really the last straw that broke the camel's back-it was the total effcct of all the straws put together. So the first straw is just as important. The same can be said of cy linder COOling fins that get packed ~ith straw, grass, leaves, and other debris when you're operating out in the boondocks. The total effect can give you a cracked jug! Take a Mojave (CH·37), for example. The engine cooling fan takes hefcy bites of air all the time. And if she's roostin' on a fresh cut field you can bet that some straw, as well as air, is going to be sucked in by the fan and get packed into the cylinder cooling fins. 'Course nothing will boost cylinder head temperatures like garbage-filled cooling fins. And if the cylinder heat isn't passed into the air stream-well, something's got to give!

Thai's why when you eye any recip cngine on a daily or intermediate, it's a good idea to focus on the cylinder fins. When you find debris, you may be able to take it out of the fins by using your fingers. But if it's really packed in, compressed air should do the trick. Another air intake on your Mojave that can swallow debris, even though there's a protecting screen up front, is the carburetor air intake. Under field conditions a certain amount of grass can be drawn into the duning and find its way to the screen on top of the carburetor. 44

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So how can you see into the ducting to find out whether the carburetor screen is dean? You can't. But if there's a lot of loose material in the air during engine runup or low altitude hover and the pilot gets a drop in manifold pressure after take off from a grassy area, you have a mighty good reason for checking the carburetor air screen. To check for debris on this particular aircraft, all you do is disconnect the rubber boot and reach in to the Screen. You can easily clean it with your fingers. 'Course if you want a real good look at this screen, follow the disconnect poop in Chapter 2, Section 111, paragraph 3-201 of TM 55·1520-20320 (11 Sep 61) for the Mojavl:.

Yessir, there's just one way to keep any recip engine cool and healthy, man, and that's by eyeing the cooling fins and the carburetor screen from time to time.

SAFETY BELT CHECK Dear Windy , The orgatlizational maintenance manual for my bird says that safety belts should be weight tested every third periodic impectioll. But Table XXIX in TM 55-405-3 (IO AJay 62), IIMai'1ltena'1lce of Aircmft S9' W. O. D.

Dear Sergeant W. O. D., Normally, when there is a conflict in instructions, you follow the organizational maintenance manual. But there can be an exception to this rule, especially when newer info comes out. So the latest poop on safety belt testing in TM 55-405-3 will be picked up in your maintenance pub with the next change. The l2-month setup is correct. 45

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MATCH

Dear Windy, TB 55-2810-207-2011 (25 fun 63) gives tIS different TBO', for ollr Bird Dog (0-1) engine. Using 115/145 Avgas we can go to 800 hours if we have exhamt valve 4065] in the cylinders, and 1000 hours if we have exhamt valve 626540 installed.

Good deal. But we don't know which exhaust valve is in the cylinders.' Can you give 1IS a hand? SFC R. O. R. Dear Sergeant R. O. R., Can do. Here's a list of all the cylinders, and what!s in 'em, on the 0-470-11, 0-470-

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ENGINE MODEl 0-470-\1 0-470-\1 0-470-\1 0-470-\1 0-470-llA 0·470-\1A 0-470·11 0-470-11 0-470-11 0-470-IIA 0-470-11A 0-470·15

CYUlDER HEAD NUM8EI $324$2 mm $12m $324$2 $124$2 mm $16727 $16727 m727 536727 536727 536727

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Dear Editor, There's one point any mechanic will admit about putting a new part on a bird-it's not going to do a job if it's not made right in the -first place! Take the recent case of a couple of boxes of castellated nuts, AN 310-4, FSN 5310-167-1285, used on just about any bird you'd care to mention. \X'e found that some of the nuts had little or no threads at all, while others 46

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Dear Windy,

TB 55 -2810.207-20/1 (25 Jun 63) gives tIS different TBO's for our Bird Dog (0-1) engine. Using 115/145 Avgas we can go to 800 hours if we have exhaust valve 40651 in the cylinders, and 1000 hours if we have exhaust valve 626540 installed. Good deal. ENGIHE CYUIIOER But we don't know which exhaust MODEl HEAD JtUMI£I: l324l2 0·470-11 valve is in the cylinders.' Can you give us 0-410·1\ l32412 a hand? lJ2412 SFC R. O. R. 0-410-11 l324l2 0·410-11 Dear Sergeant R. O. R., 0-410-11A 532m 0-410-lIA l324l2 Can do. 0-410·1\ mm Here's a list of all the cylinders, and lUm 0-410-11 . 0-470-11 what!s in 'cm, on the 0-470-11, 0-470mm m121 0-410-11A O·410·lIA m127 0-410-ll lU121 l36m 0·470-1S

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I Dear Editor, There's one point any mechanic will admit about putting a new part on a bird-it's not going to do a job if it's not made right in the nrst place! Take the recent case of a couple of boxes of castellated nuts, AN 310-4, FSN 5310-167-1285. used on just abclUtany bird you'd care to mention. We found that some of the nuts had little or no threads at all, while others 46

had the threads cut too wide apart. There wasn't a good dne in the whole lot. That's why we eye aDd try a new part before installing it. Then we can tell right-off whether or not the new part will do the job it's supposed to do. Sgt J . R. Snyder Fort Knox, Ky. (Ed Note-A good genera/rule to follow. No doubt an EIR is in the works on the nut!) 47

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