Flying Classics

Everything Franklin.

[batthyany]

[flyingclassics]

This is the stuff! Apply it right.. there is only one proper way!! I just got the info from the horse's mouth!!

[flyingclassics]

Permatex Questions Answered! (aka "I just called Permatex!)

This is one thing that has always been on my mind. When I was younger I had a friend who's father ran a glue production company. If I didn't properly apply even Elmer's glue, I would get an earful from my buddy. 

1) Apply a thin, even coat on both surfaces.

2) Stick them together.

3) Pull them apart and let the glue "breathe".

4) Once tacky, mate your surfaces.

5) You have achieved adhesion Zen! 

When I first started working on aircraft engines, my old friend Permatex showed up again. Having used pretty much all of their products working on old cars, (especially classic VW bugs) I had my own tedious bonding method. But everyone has an opinion, and being nicknamed "Permatex Pete" at work has always made me question my application methods.  Some people would just coat it on, others would just put it in sections, There were about a million opinions about how to properly put Permatex on a gasket. Well, here it is...

I figured calling Permatex would be a fun piece, and I hope the folk at my old workplace get a kick out of this! (love ya guys!)

I am pretty sure option 3 was tech support.

Anonymous Permatex Tech Support Guy:" Permatex tech support, how may I help you?"

Me: " What is the proper application for Permatex #3 Aviation?"

APTSG: "The proper application would be for Aviation".

Me:" I mean what is the right way to put it on?"

APTSG: " Are you having a hard time with something?"

Me:" No, I have just been debating with my co-workers about the best way to use it, and everybody seems to have a different opinion. One time, during a new customer's repair, I saw so much Permatex on an engine it was in the oil filter and all over the block after i took it apart and cleaned it off! It took us a while to figure out what it actually was!  who would do that?"

APTSG " WOW! That is nuts! (laughing) That is clearly not the way to use it!"

Me: " Yep, so what is the most recommended way to apply Aviation Permatex #3?

APTSG:" What we always say is if you are using it as a dressing over a gasket, use the brush-top applicator and apply a thin, even coat on each side of the gasket. Don't try to build up alot of material between the gaskets. If, for example, you are applying it to a black gasket, and all you can see is Permatex brown, you are putting waaay too much on. you need to be able to see the natural color of the gasket through the Permatex!

Me: Nice!

APTSG: " It's like spraying cooking spay in a pan, you want a nice even coat of cooking spray before you throw the eggs on" 

Me: I can cook eggs with Permatex?

APTSG: " Definitely NOT!"

Me: " When using glue, my buddy always told me to lightly coat each surface, pull apart for a few mins, and then apply. I have used that method with Permatex #3 as well. I do these 3 things

1) Light, even coat the the area where the gasket is being applied.

2) Light, even coat the side of the gasket that contacts the area that I just applied Permatex #3 to.

3) Put gasket and area together, and pull apart for at least 1-5 minutes.

4) Put together.

5) Light, even coat other gasket surface.

6) Light, even coat other metal surface.

7) Place together, and pull apart for 1-5 minutes.

8) Put together (and tighten/torque per manual.)"

APTSG: "Yep! Just like gluing principles..just don't load up both sides."

Me: "Thanks! can I use your name?"

APTSG:" Nope! Is there anything else?"

Me: "Nope! Thanks!"

In conclusion, from the bird's mouth, light even coats on every surface! Make sure you can see the gasket color through the brown of the Permatex #3. Clean your cap and bottle after each use, and........

DO NOT USE TO COOK EGGS!!!!!!!

Pete

[flyingclassics]

Thanks for making this blog! It is very informative, and I love reading about stuff like this! Keep up the great work!

Thanks very much! I want pilots of these classic aircraft to be more aware of what keeps them in the air!

[flyingclassics]

The destructive hazards of unclean push rod tubes

Man have I seen this a few times! If you forget to polish out the insides of your push rod tubes, say bye-bye to your engine!! Consider this, if each tube has 6 barely visible grains of sand, glass, metal shards, you name it, and you have 12 tubes, you are looking at 72 grains of material that will get into your crankcase and eat up your main and cam bushings to start! why risk it? Here is a nice easy, and fast way to clean them out to reveal a beautiful, polished interior:

I take a piece of scotch brite pad and wrap it around and old push rod (That I will never use in an engine.) Just one wrap will be enough. duct tape it on, and the other end will fit perfectly into a 1/2" drill chuck. gently slide it up and down the rod tube tube polishing the inside diameter. keep stopping and looking to make sure you got everything off the sides. Once it it polished, you will be proud of your work. Now its time to clean it out with a high flash mineral spirit, and paper towel until absolutely spotless!

Inspect and measure according to Franklin manual!

Wash, rinse, repeat X12!

[flyingclassics]

This is what the inside of your push rod tubes should look like when you look into them while facing a window or a light. Be sure to look all around and check for corrosion, or anything sticking to the sides that will harm your main and cam bushings!

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There are a few areas like the main bushing stud nuts, and washers, where it feels like you are playing this game.."Just don't hit the sides and drop the washer!"

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A messy engine room is a sign of future potential engine problems! 

[flyingclassics]

Nuts, Bolts, and Washers: OH MY!!

Cleanliness! I have walked into several engine shops and have seen used parts on the floor, along with heaps of nuts and bolts and washers all over the place. Its like a washer city! This is not only a sign of disorganization, but it's potential for catastrophic engine failure! Here's just one reason why..

While assembling the engine during overhaul, there are a couple of sensitive nut/washer installations. When I mean sensitive, I mean it's like that old game "Operation"  and you are at risk of dropping the washer into the partially assembled crankcase. I am talking about areas like the main bushing studs, cam bushing studs, and God help you, the accessory drive case. There is a little hole there, gives me nightmares every time I get to that point. The list goes on.

While working in these sensitive areas, you could drop a washer or a nut, and it could land in the case, or on the floor. If a shop floor is full of hardware, or has ANY hardware on it, and that washer falls on the floor, how do you know? maybe it is still in the block and you just didn't see it? 

This is why when I see a messy shop and even a SINGLE washer on the floor, I have a heart attack! I know everybody drops a washer...but this is an engine room! it should be as clean as a surgeons room!

The best way to keep track of your hardware, is to prep EXACTLY the number of nuts, washers, and bolts you need for each section. Count and double count. This way if you are missing one or have an extra one at the end of installing that section (i.e connecting rods, main bushing studs, accessory drive, cam bearing studs, engine tie bolts..) You know to hit the brakes, and find out what is going on.

If you as a customer, walks into an engine room, and it's not absolutely spotless, and there is hardware all over the floor, and used parts everywhere, I would find somewhere else to get my overhaul done.

[flyingclassics]

This little guy, with the help of your A&P can keep your engine leak free, or put you in a pretty sticky situation!

[flyingclassics]

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Silk Thread? are you kidding?

I found this great article on the dangers of improper application of silk thread on your engine. I am going to pick out my favorite parts here. Silk thread is applied on the crankcase as a gasket where no gasket material is used. It's pretty amazing it's still used. How was it decided that silk thread be used? did an engineer run out of gasket material and pulled some thread from his shirt? What kind of engineer wears silk..

In the assembly procedure of a piston engine, it is standard practice to use silk thread and a thin film of sealant to seal the crankcase parting surfaces. Engine manufacturers outline this procedure in their overhaul manuals, and it is an acceptable method of sealing these surfaces. But if silk thread is used in other areas of the engine during assembly, namely around the bearing saddles at the thru-studs, it can lead to disaster.

With the good intention of preventing possible oil leaks, some mechanics have gotten in the habit of applying sealer and a ring of silk thread around the thru-studs. While this may seem like a harmless practice to try and reduce oil leaks, sealer and thread applied at this area can cause a catastrophic engine failure.

James L. Tubbs, vice president of engineering at Engine Components Inc., has been involved in numerous accident and incident investigations where the failures stem from the addition of materials between the bearing saddles. He points out, "We have conducted comprehensive engineering analysis of these phenomena, and the results are clear!"

It can be hard for a mechanic who is not an engineer to understand why such a harmless seeming procedure can be so detrimental to the engine.

When engineers design an engine, they perform analysis on all of the stresses involved with each part. These stresses as well as temperature changes and fatigue are taken into consideration when figuring how much preload must be applied to the part. This preload is the clamping force that the bolt will be applying to the part.

In order to achieve the desired preload, the engineers take the preload that is required and convert that into a torque value to use when torquing the bolt. When figuring out this torque, they take all of the factors like the bolt size, material, and friction into account. Varying any of these factors will affect the effective preload that is being applied. For example, if the procedure calls for lubricating a bolt before torquing and it is not, although the torque wrench may indicate that the desired torque was achieved, the actual preload will be lower because of the added friction when torquing. In addition, damaged or dirty threads can reduce the amount of preload applied.

In the same manner, the bolted joint preload for the thru-studs is a critical factor. When torquing these thru-studs, if gasket material and silk thread are added to the thru-studs, although the indicated torque may be reached on the torque wrench, the effective preload will be lower. Instead of a firm preload being applied to the part, the gasket material acts like microscopic springs. The result is an effective loss of preload on the assembly.

I think you get the point, but I highly recommend you read the article. I will attach a link to it in a minute. There is a reason why you have to follow every step in the manual!!

http://www.aviationpros.com/article/10387221/silk-thread-incorrect-use-can-lead-to-disaster

[flyingclassics]

Proper cool down and warm up a MUST!!

George Kramer from East Coast Helicopters in Gettysburg, PA has been a Franklin/Hiller service tech forever (pretty much). The most common serious damage he sees from pilots is skipping proper warm up and cool down!

These failures from not warming up and cooling down properly puts lives at risk! (and cost a ton of money). It's not something you can get away with even once! These little engines are working very hard and the metal can crack at anytime! It's basic physics.

Catastophic Failure #1 Improper Cool Down

If you don't properly cool down your engine, you are at serious risk of cracking your precious cylinders! Don't forget you are flying an air-cooled engine! Those cylinders get really hot, and sensitive. Consider the cylinder's fin filled exterior as the human body's extremities (fingers and toes). Their job is to maintain the "body" temperature of the engine, and if you cool down too fast, they get frostbite, and crack. After that crazy analogy, all I am trying to say is if you just shut down after a solid flight, the cylinders could cool down TOO FAST, thus cracking the thin walls, which is surprisingly easy to do.

Catastrophic Failure #2 Improper Warm Up

I know you want to get right up there, but follow the warm up procedure every time! If you don't, it can lead to stuck valves, and the next thing you know, you are in the middle of an emergency landing with a push rod sticking out the side of one or more of your cylinders and oil EVERYWHERE!

[flyingclassics]

Proper torque order stops induction leaks!

It's all in the manual.. I know you are excited to get those cylinders on, The feeling you get as a builder/hobbyist is amazing to see them all on the crankcase. But wait!! don't torque them yet! you have to install the intake manifolds, then torque the cylinders. If you miss this, you are looking at a world of issues later down the road.. wait not road, later in the air?  

Look in the manual, double check it.. This is a common mistake made by hobbyist engine builders and pros alike. Not seating the intake properly with the cylinders will cause induction leaks and cracks later when the engine is up and running due to vibration. Also, look in the manual to make sure you have installed the induction packings properly. There is a trick to it. if you think you don't understand it, call a pro for help.

[flyingclassics]

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Oil pressure part 2

The elusive Phil Davis from Davis Aviation in Tennessee finally got back to me, so I figured I need to put it on due to the fact that it's gold.

Phil Davis says that when your pressure drops, the first thing you do is to took at your oil temp. If the pressure is very low, LAND!! find the nearest airport and land, even if it feels fine.

You want to start with the simple things. if your temp is fine and the pressure is low, check for oil loss. It should be obvious, like, look down, you are probably standing in it.

If you are not swimming in oil, lets not break apart the engine quite yet. Lets look at your gauge. The electric ones tend to be the first to go. Test your leads. could be a broken wire,bad connection or splice.

Other simple things are bypass plate, sticky plunger, debris or excessive wear on plunger and plate.

Some people add an oil filter on their fixed wings.. This too will cause a noticeable drop in oil pressure.

Phil also says the oil temp gets hot and pressure drops during climbing.. if you are climbing, and the drop in pressure makes you nervous, level out first and see if it goes back to normal before you radio an emergency landing. 

Oh yea, take it easy on these old birds and stop climbing so darn hard all the time!! Its an antique, not a leer jet!!

Thanks Phil!