A few annual questions

[Skates97]

6 hours ago, Raptor05121 said:

Flaps should be 4.5 pumps to get 33* of deflection

Keep up the work. The bits look pretty dirty. If I find a day off, I get on my mechanic's crawler and I clean up my landing gear bays, etc. Makes it easier to spot leaks and stuff.

What are all the counter-sunkscrews for? Looks like you took out the inspection panels under the wings?

Probably a stupid question, but what do you guys use for cleaning up the grease/gunk in the landing gear bays? If it was on my car I would just use some plain old degreaser and a rag, but new to the plane ownership experience and a bit nervous about doing more harm than good to it, just thought I would ask.

[TheTurtle]

Anybody know the number of screws in the inspection panels?  Dont really want to count all the ones I have out   I was going to make an order from spruce for SS ones but I saw they dont have an option for "metric shit ton" under quantity...  I was going to guess 150ish? 

Also I figured Id get all the same length.  Will 1/2 inch work for all of them?  Mine are anywhere from 1/2" to 1.5". 

and lastly I know Clarence has mentioned more than once the thread size on these forums but after 15 minutes of googling the site I cant find it.. are they 1/4-28 threads?

[carusoam]

The MM has all the screws listed... 90% are the same size...

It is a pain to remove all the panels, but corrosion is a killer.  If it starts, it progresses quickly.  Better to look and see nothing... any time the driver slips, toss the screw, get another...

SS screws are easy to put in and out compared to the rusty originals.  Electric screw driver with the torque set way low finish torque by hand...

Cleaning, soap and water.  Wd40...

By the third year everything is the way you want it to be. By the tenth year you are repeating some expensive thing you din't think you were going to do again...

Finding tiny screws and spring/nut devices for the dog house is a challenge.

get a good look at each rubber hose that is either touched by oil or gas or hydraulic fluid.  They are slowly degrading by adsorbing the organic fluid.

Fuzzy Memories of a decade of M20C annuals... not a mechanic.

Best regards,

-a-

 

[Guest]

6 hours ago, Bob_Belville said:

I believe you only need to remove wing panels 12, 13, 14, & 16 = 6 per side for inspection and some lube. 

page 2-15 REV. D 8/1/81

MAN106 C,E,F,G.pdf

There in lies one of the many differences between "annuals". Stuff goes wrong behind the other panels as well.  I've worked on planes that still had covers which never were opened years after the paint job was done.

Clarence

[cliffy]

While you're at it you might want to check the age/condition of the fuel pressure hose and the oil pressure hose from the firewall to the gauges. Also the hyd fluid hose from the hyd. reservoir to the pump.  Many times they are as old as the airplane. The flap supply hose can be routed a slightly different way and not go through the small hole that the factory used when building the airplane. Much easier. 

[TheTurtle]

Just now, cliffy said:

While you're at it you might want to check the age/condition of the fuel pressure hose and the oil pressure hose from the firewall to the gauges. Also the hyd fluid hose from the hyd. reservoir to the pump.  Many times they are as old as the airplane. The flap supply hose can be routed a slightly different way and not go through the small hole that the factory used when building the airplane. Much easier. 

those hoses were both squawked at PPI.  Replaced them as my first project.  Didnt want either of those fluids spraying around!!

I will recheck the hydraulic fluid hose. 

[Yetti]

I have found Goop Hand cleaner to be quite good at cleaning lots of things.   You can get it at Homer Dan.   I also like the Liquid Wrench Silicone Spray for cleaning things  10-24 is a popular size on the F

[47U]

If you're already replacing o-rings in the pump, you might consider doing the actuator at the same time (along with the hoses, as Cliffy mentions).  You'll only have to bleed the flap system one time for many years to come.

Looking at your actuator picture, has the stub spar beef up plate (SB20-217) been done?   Mine was cracked, but the crack wasn't visible until I pumped the flaps all the way down and put some pressure on the stub spar.

Getting to know your airplane as you are is to be commended.  Nice work!  

[Bob_Belville]

The pitot tube takes a beating from rain. The nickle(?) plated part is attached to the painted mast with 4 Phillips head screws that seem to be an odd size. They're rusted and I like to replace them but don't find 6-40 x 3/16". (Not 6-32 or 4-40!) Perhaps they were provided with the instrument?

Clarence? Anyone else have a resource?

[Hank]

McMaster-Carr should have them. www.mcmaster.com

 

If it's not in MSC's Big Book, you don't need it. www.mscdirect.com

[Bob_Belville]

14 minutes ago, Hank said:

McMaster-Carr should have them. www.mcmaster.com

 

If it's not in MSC's Big Book, you don't need it. www.mscdirect.com

Sure 'nuff. Phillips Head @ 1/4" long or hex drive @ 3/16" 

 

Lg. Threading Head Dia. Head Ht. Drive Size Tensile Strength, psi Pkg. Qty.   Pkg. 18-8 Stainless Steel 6-40                   3/16" Fully Threaded 0.262" 0.073" 5/64" 70,000 10 92949A336 $5.87         Product Detail     18-8 Stainless Steel Hex Drive Rounded Head Screw, 6-40 Thread Size, 3/16" Long     Packs of 10   Lg.	Threading	Head Dia.	Head Ht.	Drive Size	Tensile Strength, psi	Specifications Met	Pkg. Qty.		Pkg.
Passivated 18-8 Stainless Steel
6-40
1/4"	Fully Threaded	0.27"	0.097"	No. 2	80,000	Fed. Spec. FF-S-92, Fed. Spec. QQ-P-35, MS-51958-26	25	91400A170	$12.50
Product Detail     Mil. Spec. Phillips Rounded Head Screws, 18-8 Stainless Steel, 6-40 Thread Size, 1/4" Long

[Guest]

1 hour ago, Bob_Belville said:

The pitot tube takes a beating from rain. The nickle(?) plated part is attached to the painted mast with 4 Phillips head screws that seem to be an odd size. They're rusted and I like to replace them but don't find 6-40 x 3/16". (Not 6-32 or 4-40!) Perhaps they were provided with the instrument?

Clarence? Anyone else have a resource?

Bob,

6-40 NF sounds right.  Harder to get AN MS series, industrial may be the choice.

Clarence

 

[Raptor05121]

17 hours ago, M20Doc said:

How do you inspect the plane without removing the inspection covers? The amount of work can be reduced by choosing correct length screws.  Most Mooneys I've encountered have been assembled with loads of incorrect screws.

Clarence

 

The smaller oval ones are inspection panels. The large square ones are close-out panels used to reach things in final assembly. As least that's what I've been told by a few people.

[madjano]

My mechanic swears the SS screws heat up more going in and make it PITA to get them out next go.  Any truth to this?

[Raptor05121]

The countersunk ones?

[madjano]

9 minutes ago, Raptor05121 said:

The countersunk ones?

Yup, for the wing inspection panels.  

[Raptor05121]

I replaced all of mine and put a tad bit of lube on the tips when I screwed them in. I highly doubt turning them in will get them hot enough to deform

[Guest]

52 minutes ago, madjano said:

My mechanic swears the SS screws heat up more going in and make it PITA to get them out next go.  Any truth to this?

He's not the only one. They do tend to bind in the nut plate unless both are well worn.

Clarence

 

[carusoam]

Compared to the rusty old originals my SS ones were nearly garaunteed to come out the next year. The originals had a tendency to strip out where the driver would slip. Followed by drilling it out.

What choices do we have lately?

It also helps to have a maintenance manual that tells the right hardware to use.

Best regards,

-a-

[Vance Harral]

We went to all SS screws a while back and I do notice they occasionally bind up going in or out, even when new.  But I always assumed it was just a random thing, not particular to SS screws.  Certainly no worse than dealing with a corroded cad-plated screw.

In practice, these bind-ups aren't a big deal.  I've never had one bind up so badly I couldn't remove it easily with a good hand screwdriver (well, not including a couple of "pilot errors" where I cross-threaded the screw).  We made a project a couple years ago of replacing all the inspection and belly panel screws with new, correct hardware.  Ever since then, we've kept a little bin of fresh screws and nut plates readily available.  Any time a screw binds up or cams out, I just replace the screw and/or the nut plate with hardware that doesn't bind.  We probably wind up replacing a dozen or so screws per annual, for trivial effort and cost.

[Hank]

Me, too, Vance. Same experience. I replace screws every annual for being tight or for buggering up the slots in the head. Also started using the plastic washers between every screw and it's panel, that seems to help, too. Washers are cheap, maybe 2¢ each. Inky the nut plates are expensive . . . Everything else I buy in packs of 100 for economy of purchase and ease of replacement.

[Vance Harral]

Yeah, the nut plates are spendier, but fortunately it seems the screw is usually the cause of binding vs. the nut plate.

I like the washer idea, but I confess we don't bother with it.  A lot of that has to do with the paint on our airplane being pretty old and beat up (still looks good from 50' away!).  The paint is already worn away under the screw head on most of our panels.  I'll probably feel differently about it if we ever get the airplane prettied up with fresh paint.

For all you guys with less-than-pristine cosmetics, there's a certain luxury in not having a showpiece when you're in the maintenance hangar.  I'm able to get inspection plates and belly panels off a lot quicker, since I don't have to be quite so paranoid about the occasional paint scratch from a slipped bit.  It's been nice to learn screw-craft on a less-pretty airplane.  After 12 years of owner-assist annuals, I like to think I've reached the point where I can make pretty good judgement calls on where I can use drill drivers vs. breaking out the hand tools, when I need a new bit, etc.

[TheTurtle]

after much waiting around and stressing I fired up 36M yesterday for the first time in almost a month.  Overhauled mags and no crack in the exhaust and it sounds really good and smooth.  No oil leaks other than the drips from me way overcharging the K&N airfilter...  Actually seems quieter as well.  Not convinced the tiny crack in exhaust was making it loud but I could have an almost normal conversation with the IA with the door shut and engine at fast idle.  Mag checks went fine.

Eddy current of course found no cracks in my hub.  I fixed the smoking rheostat which was caused by a short in the IP lights.  Got my flaps to come up in about 10 seconds vs less than 2.  With all the oil and grease I put in it the controls it feels like butter on the ground. 

Put the rebuilt pilot valve for the PC system in.

500 hour inspection on yoke shafts and while they were out painted them really well with 10 layers of clearcoat after the base, so hopefully i never get paint rubbing off on my hands.  and the cracked plastic is finally gone.

Raining like hell here so I'm not doing anything today but I just need to button up the cowl and swing the new compass and shes ready to fly.

[Bob_Belville]

On ‎1‎/‎2‎/‎2017 at 11:51 PM, Raptor05121 said:

The smaller oval ones are inspection panels. The large square ones are close-out panels used to reach things in final assembly. As least that's what I've been told by a few people.

Not exactly. I spent about 3 hours today putting my plane back together following inspection. The MM indicates the panels that come off, 7 in each wing (#12-16). 4 small(#14, #16 - 2ea), 3 large (#12, #13, #15). I put them back with 8-32 x 1/2" cad plated rather than ss. I've used both and I've decided the ss are a little softer and easier to bugger up.

Page 2-11.pdf

[Bob_Belville]

On ‎1‎/‎5‎/‎2017 at 4:18 PM, M20Doc said:

He's not the only one. They do tend to bind in the nut plate unless both are well worn.

Clarence

 

Clarence, isn't the thread pitch of the ss a little different?