Finally... our Finch's First Flight

By Peter Ashwood Smith

Biplanes are special! The first airplanes of course had two wings and there is something therefore very nostalgic about a biplane.  Two wings are not just beautiful, that pair of wings together are also very light and remarkably strong, however they present some challenges that monoplanes don't.  Rigging being one of the tricky things to get right!

The brand new Finch propeller shines.

We rolled out our yellow wings Finch biplane today for her first flight of the season and I was the lucky pilot asked to check her out. She has a brand new prop which is slightly lower pitch than last season's which will give a slightly better climb rate at the expense of a few miles an hour of top speed. Prop pitch is a bit like gears on a bike or car, but unlike a car or bike our Finch has only one gear. 

We also made some new "N" struts which are the black struts that keep the wing tips separated. These struts are a very important part of a biplane as together with the "flying" and "landing" wires ( the X wires between the wings ), they provide the majority of the strength of a biplane's wings (like the towers and  wires in a suspension bridge).  A biplane will often fly a little differently season to season just because the wood changes due to humidity variations etc, so when you combine new parts, like the "N" struts, a bit of tweaking to get her to fly straight is expected. Her first flight this season was therefore as expected, a bit crooked, which for a pilot is perfectly safe but rather tiring because you have to keep several pounds of force on the stick for the entire flight since we have no fancy electric trim systems so its all muscle power. However, other than some minor tweaking , which our mechanics will do by adjusting the length or the rear N strut, she flew beautifully and happily sprayed me and Gatineau with little drops of fresh grease and oil. Over the next few weeks other pilots will step back into her and she will be ready at the ripe old age of 74 to take hundreds of teenagers flying again this summer... something she has not done for over 70 years!

The Finch N-strut is shaped like... well... an “N”

Now since we just changed the lower right wing on the Tiger Moth no doubt she too will be a bit crooked on her first few flights and will need a bit of tweaking too.

Volunteers install the new Tiger Moth lower wing

John Gillespie Magee presentation event..MUST SEE

A unique opportunity to see never-before published images of John Gillespie Magee and hear is compelling story from Linda Grandfield, prolific author, historian, children's writer and national treasure.

Pilot Officer John Magee at the controls of a 412 Squadron RCAF Spitfire in England, 1941

Historian and writer Linda Granfield will be presenting a power-point show, "High Flight and John G. Magee Jr." at the Main Branch of Ottawa Public Library on Monday, April 15th. The Magee family has loaned Granfield family album photos, many never before seen. The program, one hour long, will begin at 1 p.m in the Program Room, Second Floor (near the children's department). Free.

A Must See for all History buffs, aviation aficionados and poetry lovers

OTTAWA PUBLIC LIBRARY
Monday, April 15th - 1300 hours

FREE to all

Restoration Update 8

My apologies for the length between posts, but now we're back! 

and now back to the cooling system,

This time, we were working on the other side of bulkhead right inside the center section of the aircraft. We had to fit pipe #3. I’ve taken a picture of the shop drawings to give you an idea of what the cooling system will eventually look like! 

The Cooling System

After getting the appropriate hardware (that is, nuts, bolts, washers, avemos, and avemo clamps), we were ready to install our pipe. Pipe # 3 is the lower one immediately left of the radiator, between the two bulkheads. This drawing will make much more sense once you see the picture of the pipe roughly fit. However, before we could fit them, we had to lubricate them so they would slide into place. To do this we used “electrical insulator compound.” Don’t let the name fool you though, it pretty much looked like Vaseline (though I’m sure it isn’t) and allowed us to fit the pipes with ease.

Roughly fit in place

As you can see, it’s a tight fit. The black rubber avemos indicate the joints. They will be covered later with an avemo clamp and a band-type fastener. There is a special name for the band-type fastener and I will clarify that when it is actually put on. However, when we went to fasten pipe #2 to the bulkhead (the same fashion as last week) we ran into a fair bit of trouble. Pipe #2 is to the left of the rubber avemo (at the very left edge of the picture, almost out of the frame).

The Firewall, You can see Pipe #2 in the bottom right (barely).

Above, you can see the firewall of our Hurricane. At the very top, you can see the coolant header tank. At the very bottom, slightly to the right, you can just make out pipe #2. Coolant will eventually run from the header tank to the radiator, through the radiator where it is cooled, then through pipe #4, #3, #2,and #1 into the engine. It will then circulate crucial components in the Merlin and keep the engine from over heating. Then the cycle repeats. If you look closely at the shop drawing, you can see the direction of the coolants flow. The small arrows next to the pipes represent the flow. 

But back to the problems! The first problem was that we could not get the bolts through the bulkhead and flange on the pipe itself. At first it seemed like the holes in the bulkhead needed a cleaning out. To do this, we used the drill and appropriate bit to just clean out the holes. We had to be very, very careful not to oversize the holes or “ovalize” them.

A close work environment

Once that was done, Ted and I tried once more to fasten pipe #2. However, this time it turned out that the flange itself was lining up with the holes in the bulkhead. Unfortunately, the flange is on Ted’s size and you can’t quite see what it looks like. Yet, if you remember from last week, or want to see what the flange looks like, you can see it in “Restoration Update #7.”  We weren’t sure what the problem was so we needed Paul’s opinion. Luckily, we were able to compare the fit on our Bunny McLarty Hurricane Mk. IV. So after some consultation and discussion we figured out what the problem was.

We figured out that the problem was with the ring riveted to the bulkhead. It was placed 90 degrees out. In the above picture, you can see Paul showing us how to drill out rivets. It turns out that on the ring, there is one quadrant of it where the lip is shaved down. This lip allows for the correct amount of clearance and lets the bolt holes line up with the flange. The rivets were particularly tough to remove. You first have to drill out the head just down to the surface it mates with. Then you have to chisel it off. Then you have to punch out the remainder of the rivet. In some cases that required drilling with a smaller drill bit into the rivet. This weakens it and eventually allows you to punch it out of the hole. To save breaking up each photo with a few lines of the process went as follows:

Knocking the head off of the rivet

 Repeat that process 8 times and we were ready to refit our plate and pipe #2. It took most of the afternoon to get those rivets out. Again, we had to be extremely careful not to oversize or ovalize the holes. Rivets will be going back into those holes and they need to remain the exact same size. 
 

All bolted together!

Above, you can see the pipe reinstalled and the plate adjusted. We had to turn it 90 degrees to the left, counterclockwise, to get the shaved down portion of the lip in the correct spot. Later this week, the plate will be re-riveted. Unfortunately for the general fit, turns out Pipe #3 is out of alignment now. Despite the photo below, the pipe was quite a bit closer in fit, but it wasn’t 100 percent correct. It was just really awkward to take a picture and hold the pipe at the same time. To fix this, the pipe will be heated up at its joint and positioned so that the fit is 100 percent perfect.

At the time this was discovered, we had reached the end of the day. So that will have to wait until the next session. That’s all I have for this week on the restoration. However, we have received our first question for “Ask an AME.”

John Park, a fellow Vintage Wings member asked:

You often see people turning the propeller over by hand prior to starting an engine. Especially on radial engines. Can you turn the prop either way or only the way it operates or opposite to the way it operates? Why?

Well John,

1) The propeller is pulled through by hand prior to starting to check for "hydraulic lock" (just for those who don’t know why the propeller is pulled through on radial engines).

2) Whether or not you rotate the propeller the way it runs during regular operation or not, depends.

1) “Hydraulic lock” can happen on radial engines and other inverted engines (such as the gypsy major - I believe - on the Tiger Moth). There are cylinders where their heads face towards the ground. What can happen, when the aircraft has been sitting, is that the oil from the engine can seep around the piston rings and enter the combustion chamber. Once this oil has built up in the combustion chamber, it obstructs the piston from reaching "top-dead-center" during the compression stroke. That layer of oil that has now built up between the piston and the top of the cylinder head is pretty much incompressible. The engine components aren't meant to take that kind of stress so they will give out long before that oil is compressed. When this happens, you've got hydraulic lock.

The damage that hydraulic lock can cause your engine is catastrophic. You can range from bending your connecting rods (that's the rod that drives the piston up and down) to blowing the head off the cylinder entirely. You do not want to start an engine that is hydraulically locked. If you discover hydraulic lock while pulling the prop through you must expel the built up oil before attempting to start the engine. Some newer engines have drain plugs. On others, you will have to remove the spark plug to drain the oil. You will then also have to clean the spark plug up before replacing it. Thus to prevent starting an engine that is hydraulically locked, the prop is gently pulled through by hand.

2) The reason that it depends whether you can pull the prop through in either direction is because of the vacuum pump (also called a vane pump). Generally it is good practice to pull the prop through in the normal direction of operation. However, the reason it’s a good idea to pull the prop through in the direction of operation is to protect the vacuum pump. The vacuum pump has very delicate vanes in it made of a material like carbon fiber. When you pull the prop in the wrong...or...opposite direction, you run the risk of damaging those vanes. Certain vacuum pumps strongly recommend or even prohibit you from pulling the prop through opposite of its normal rotation. This is because you run the risk of breaking those vanes in the pump. If those vanes shatter, the can also damage a number of instruments which are controlled via that vacuum pump. This is because when it is destroyed, the negative pressure (which is keeping some of your instruments active) ceases. This causes broken bits of the vanes to be sucked into the instruments themselves.

The end goal is to protect that pump and if you aren’t sure whether or not it is safe to pull the prop through opposite to its operation direction (because you don’t know what type of vacuum pump there is in the engine - or the pumps manufacture specifications), then you should not. 

Hope this answers your question, thank you John!

If you've got a question about the restoration or for Ask An AME, send me an email: ceaton@vintagewings.ca 

Until next time,

Chris 

Restoration Update #7

From flight controls to cooling systems…

Well, as promised, the Elevator trim tabs have been repainted and they look fantastic! Here’s the photo to prove it!

Freshly Painted Elevator Trim Tabs

I moved onto a new task today. I was tasked with helping Ted, another of Vintage Wings’ fine volunteers, clean and re-install the cooling lines/pipes on our Flying Officer William McKnight Hawker Hurricane Mk. XII – a task that looked pretty straightforward at first. However, before we knew it, it had taken up the entire day!

Coolant Pipes, Shop Towels, Gloves, and a coil of Lockwire

Meet the cooling pipes. These copper pipes connect the radiator (which you’ll see in a little bit) and run all they way up to the engine. Due to the fact that these pipes have been sitting around for a long while, we had to make sure they were nice and clean before re-installation. The all important engine coolant flows through these and we don’t want to have contaminated coolant. Cleaning them wasn’t too hard. All we needed was a rag, a really long piece of lock wire, and some alcohol.

The alcohol even comes in a nice little keg, although, I think I’ll stick to pints of beer, thank you very much. Joking aside, it’s incredibly toxic and flammable. So we made sure to take proper precautions when using it. 

In the above photo, you can see what we were up against. Inside these pipes was a whitish/greenish/yellowy dust. I suppose this could have been anything from dried coolant, to corrosion and perhaps a little dust. To clean this out, Ted fashioned an alcohol soaked rag with a real long piece of lock wire attached to it. We then fed that piece of lock wire through to the other end and used this to pull the alcohol soaked rag through.

Sorry Terry!

In the above photo you can see Ted (left) pulling our rag through the dirty copper coolant pipe. On the right you can see Terry Cooper waiting patiently to get back to work on or around the fire shield (I think). On more than one occasion we interrupted him. More often than not, it seems that there is always one part of the airplane that everyone’s task ends up focusing around, even if they’re completely different tasks!

Another action shot here, you can see that the rag has almost been pulled all the way through. In the picture below, you can see Ted trying to clean the remaining bits of aluminum foil from the threads/lip of the coolant pipe. That aluminum foil was put there to protect the opening while the pipes were being stripped of their paint. Did I mention that Ted is 87! Not only is Ted a true role model, but a lot of fun to work with!

After we had all the pipes cleaned, it was time to try fitting some into place. On the left, the pipe that Ted is just finishing cleaning off is the first and only one we tried to connect to the radiator.  

Left, you can see the Hurricanes Radiator and Oil Cooler. The oil cooler is the brass coloured tube protruding from the rad. We had to move it out of the way to fit our pipe. The coolant pipe connects where you can see the red cap just off to the left. That cap is in there to keep dust out of the rad. The coolant pipe then runs through the hole in the center section just to the right and behind that dust red cap.

In the shot below, you can see what the coolant pipe looked like once it was bolted securely to the center section. However, in order to get it there was another story. In the other pictures below you can see that it was quite awkward. I was having a hard enough time getting enough grip on the bolts, while Ted was fighting for space with Philip.

           

Some quality bonding time.

 It was quite the tight spot back in there, but after a little perseverance and TLC, we got the coolant pipe secured.

So close!

However, even after that entire struggle, it turns out our pipe didn’t fit so well. The threads, or grooves if you will, should be concealed inside that rubber connection (which I believe is called an avemo). This turned out to be quite important though. We figured out why it wasn’t fitting properly. It turns out, either the bolts holding the radiator on haven’t come in from order yet or they just hadn’t been swapped. Right now, there are four temporary bolts that aren’t quite the right thickness. As a result the rad is sitting a little bit low. If all goes well, when the hardware is swapped it should fit nice and snug…fingers crossed!

Between various questions being asked, tools searched for, and pipes struggled with, the day had come and gone. So in order to avoid having to clean all the coolant pipes again, we covered up their ends with some masking tape.

All ready for next Saturday.

Next week, when Ted and I revisit the coolant pipes and rad, we’ll hopefully be able to get them fit properly! Well that’s all I have for this week, but don’t forget! If you ever have any questions about the restoration, the history of the aircraft, Flying Officer William K. McKnight – the inspiration of our restoration, or you have a question for “Ask An AME” feel free to send me an email:

ceaton@vintagewings.ca

Until next week, Take care!

Chris

Hurricane Restoration Update 6

A little while more with the trim tabs,

Two Saturday's ago I finally made my way back to the Hurricane. The task I undertook was a bit simpler than the compression test from a few weeks back, but equally important. This task involved removing, and preparing for painting, the elevator trim tabs.

Trim tab on the left elevator of the Flight Lieutenant Bunny McLarty Hurricane IV – the world's only flying Mark IV

Now before I took a picture of the task I was assigned, I had already removed the tabs on the Mk. XII. However, seeing as they are exactly the same on the MK IV, a picture of the tabs on the MK IV will serve nicely for showing where I began.

Close up of trim tab on Hurricane IV elevator.

Interestingly enough, removing the trim tab is not as complicated as it looks. Well to take only the tab itself isn’t all that troublesome. It is merely held in place by two bolts and two nuts. If you wanted to service the chains and pulleys that operate it, then you’d have a job on your hands. The chain, cables, and pulleys are concealed underneath the fabric. To get at them would be quite the pain in the arse. However, luckily for us, the Mk. XII isn’t fabric covered yet.

The starboard elevator trim tab location on the exposed structure of the Flying Officer Willie McKnight Hurricane XII

Pictured above, the starboard elevator trim tab has been removed. On the right hand side, where the dark green paint is, is the control for the entire tab and where it is bolted in place. On the opposite side, there is a hole for a pin (which is attached to the tab itself). But back to the right-hand side of the photo, if you look a little past, you’ll see a box and a chain running towards the nose from the box. That chain then goes around another pulley and connects to the trim cables which then runs into the fuselage and up to the cockpit.

The attachment point and control linkage point for the starboard elevator trim tab

That aside, there is only a very small mechanism that actually moves and activates the tab. The piece you can see the bolt going through in the picture above rotates when the trim is adjusted from the cockpit. As the back end is a pin, the tab rotates up and down with ease. To better illustrate, see the picture of the removed tab below:

Trim tabs are ready for paint prep.

Now you can clearly see the pin end and the U-shaped end that attaches to the rotating/adjusting mechanism. Now it was time to prepare the tabs for a repaint. After using scotch-brite to scuff up the current paint job to allow the paint stripper to penetrate, it was time to bust out the chemicals.

Tal-Strip II. So powerful it can clean off a Boeing Globemaster with just one bottle…well I suppose that might be a bit of a grandiose claim, but it’s one way to market otherwise normal paint stripper. In the second picture you will note its’ turquoise colour, its’ jelly like texture and appearance, and its despicable smell/odour…or perhaps that last one’s just me. Also, stripping various aircraft parts is a task apprentices will often do when they get hired. I now see why, though I quite enjoyed it because I was working on a Hurricane, I can see it as being a less-than-desirable task. Nonetheless, for our restoration and any other project, protecting parts against corrosion is important and our Hurricane could use a new coat of paint.

Due to the fact that I had pre-scuffed the paint, when the stripper was applied, it was able to “get underneath” and “lift” the old paint off. It was then just a matter of wiping and scraping it off. Then once that was done, the pieces were rinsed with water (because water neutralizes the acidic paint-stripper), tagged, and placed on the shelf to await painting. I will show a picture next week or whenever they are given a fresh coat of paint to show the difference.

Some of the other tasks that were completed/worked on, of which I didn’t get a picture, included making some new gaskets to protect some of the flight controls when they pass through a firewall, installation and running of the elevator trim cables, inspection of the wings and aileron cables, and cleaning out of the alternator and generator and preparing them for installation.

That’ll have to bring this week’s session to a conclusion, I apologize for such a short one, but I suppose only so much can be said about stripping paint and we’ve already had a lesson in trim tabs.



Looking forward to next week, until then, take care!

Chris Eaton, the Bloggin' Vintage Winger

Restoration Update #5

Let’s take another look at that tail...better pull up a chair too.

            Rudder Trim 101 is brought to you by Terry Cooper & Ed Durand. Thanks to Terry’s lesson and an Article from Ed on the very tragic Reno 2011 Air Race crash of “Galloping Ghost” (The cause of the crash was a defective/broken off Elevator trim tab on a modified P-51D). I can now follow through on my promise to explain the significance of the trim tab. I am also most grateful for Terry’s conversation; a quick lesson on rudder trim digressed into a lesson on fixed pitch and constant speed propellers, which further digressed into a lesson on the propeller governor, but not before a digression on private aircraft powerplants (such as the Lycoming and Continental), before finally digressing back to trim tabs! A very well spent and much appreciated hour and a half, Thanks Terry and Ed!

That's a nice Hurricane tail

Rudder Trim:

Pictured above you can see the rudder and tail of our Hurricane (and an additional picture that’s easier to see the rudder trim). The solid, green vertical bar in the foreground of the picture is the Hurricane’s rudder trim tab. The trim tabs are primarily used to relieve pressure from the control columns. For instance, when air is flowing over the wings and stabilizers it puts pressure on the control surfaces depending on the direction you are heading. Some aircraft have trim tabs on their ailerons, elevators, and rudders. I believe our Hurricane only has Rudder and Elevator trims. However the rudder trim tab also serves an additional purpose.

The propeller is essentially a gigantic gyroscope. It, when spinning, pretty much forms a giant disk. It is also spinning in a particular direction. On aircraft that are tail draggers, that is, aircraft that have their landing gear beneath the tail section and rests on its tail, the rudder trim is critical for take-off. The Hurricane is a tail dragger. So when the Hurricane is moving forward on takeoff, it wants to go in the direction of the spinning propeller. That’s because there is force acting on the aircraft, 90 degrees, causing it to want to do a 180, or change directions. So if the propeller is spinning clockwise (from the pilot’s point-of-view), on take off, force will be hitting the aircraft on the pilot’s right-hand side making it want to spin-out or turn 180 degrees. By activating rudder and setting the rudder trim, the pilot is able to counter-act that 90 degree force and maintain a particular heading for take off. Likewise while the plane is in flight that force is still pressing on the aircraft but to a lesser extent because the power level is lower during cruise than it is during take-off. However, the principle remains the same, the rudder can be utilized or the trim to counter act the force and help the pilot maintain a straight heading.

Now, that’s about it for the Rudder trim and I apologize if I horribly botched that explanation. If I need to make anything clearer or if you have any questions I will try to answer them next week! Unfortunately I didn’t snap a picture of the reinstalled locking pin and landing gear on the Spitfire, however, it looks exactly the same as the installed landing gear from last weeks blog with the addition of a tire. All you need to do is imagine a stainless steel pin instead of a brass one!

Ok so now let’s talk about what happened Saturday. Well again I was not working on the Hurricane, but equally exciting things were done on the Spitfire. Philip and I were tasked with running a compression check on the big V-12 Merlin, the heart of the Spitfire (and eventually on our Hurricane {but the smaller Merlin 29}). I started this blog in the hopes of keeping it about the Hurricane but I seem to have gone off-topic the past few weeks. That doesn’t mean that nothing has been done on the Hurricane, we have a small army of volunteers working on it. I will make sure that if I do not work on the Hurricane a particular Saturday, I will take note and pictures of what’s being done. Then we can return to the original purpose of this blog. In the mean time, I hope you have found the work being done on the Spitfire interesting, I sure do. And who knows, the Hurricane will need a compression check done eventually so consider this a practice round!

The Compression Check:

The compression check is done to ensure that the cylinders are maintaining the proper level of compression during the compression stroke of a reciprocating engine. Piston engines in aircraft are generally 4 stroke, 5 cycle/event engines:

 1) Intake stroke, where the piston moves downwards in the cylinder drawing in fuel and air mixture.

2) Compression stroke, where the piston moves back up in the cylinder compressing the fuel/air mixture.

* Then you have ignition or combustion, where the spark plug ignites the fuel/air mixture once the piston has compressed it and reached a certain point before top-dead-center (the point when the piston is at its highest on the upstroke before going back down).

3) Power stroke, where the ignited fuel/air mix drives back down the piston doing useful work, turning the crankshaft.

4) Exhaust stroke, where the spent fuel/air mix is pushed out the exhaust valve as the piston goes back up.

Then the process repeats; 4 distinct strokes, 5 different events. The only time the piston does any useful work is on the power stroke because that is the stroke where it is being used to turn the crankshaft. In order to have a successful power stroke, the fuel/air mixed needs to be compressed to a certain psi (pounds per square inch) of pressure before it is ignited. If not, it will not exert the appropriate amount of force during the power stroke and the engine will run inefficiently (also probably a sub-par explanation but I haven’t got that far in my Powerplant text yet).

The first thing we had to do on the Spitfire was remove the spark plug leads and spark plugs. The Spitfire has 24 sparkplugs all together, two per cylinder. By removing one bank on each side, an adapter could be placed in and the cylinder compressed (more about that later though).

Packard built Merlin 266 

Pictured above you can see the beautiful Packard built Merlin 266 in the Spitfire. The silver wires are the Spark Plug leads. They screw into the top of the spark plug and send the electrical current, or spark, to the spark plug from the Magneto. That spark then ignites the fuel mixture and so on in that particular cylinder.

Above you can see two spark plugs with their spark leads removed

In the picture above you can see 5 spark plugs removed on the “A” bank. Rather than calling the two banks of the engine left and right, the British opted for A and B. I guess that makes more sense because depending which side you side of the engine you look at, the “right” and “left” bank could easily be confused. We also had to take the spark plugs out in a particular order. We took them out from the one closest to the propeller (“A1”) to the one closest to the cockpit (“A6”). This was to ensure that they are returned to the proper cylinder. As you can see they are quite dirty and in need of cleaning. The engine was like running rich (meaning a high percentage of fuel in the fuel/air mix) because most of the flights were short. That means the Spit spent a lot of time taxiing and running on the ground where the fuel mix is set to full rich (I believe).

Looks kind of like the space control unit I built at home

Anyways once they were out on both sides we could do the compression test. I mentioned earlier that only 12 of the 24 were taken out. This is because if we had removed both, when air was forced into the cylinder it would have escaped out the other spark plug hole and it would be impossible to do the compression test.

To do the compression test, an adapter was fitted to the open spark plug hole and a regulator and air hose connected to that adapter. However, before doing that, the piston in the cylinder being tested had to be at top-dead-center (tdc). Once the piston was in the correct position air could be forced into the cylinder. The easiest way to tell when the piston was at tdc was by looking at the valves and camshaft.

The “B” bank camshaft and valve assembly is to the right of the exhaust port in the above picture (look down from the 3 gears in the foreground. From there to the propeller are all 24 valves for “B” bank). Each cylinder has two intake valves and two exhaust valves for a total of 48 valves. To get the piston for ‘B1’ at tdc, the propeller had to be rotated around until the nubs on the camshaft were facing up. This means that all four valves for that cylinder would be shut. If they were shut, the piston was at tdc and air could be forced in through the air hose. The valves are springloaded. When the nubs are up, there is no pressure on the spring and the valve remains closed. When the nubs are down, pressure is put on the valve and spring and the valve is pushed open.

However, even before that Paul put the fear of God into me (for good reason). Because the piston is being compressed in the cylinder, it’s being driven downwards by the air. When the piston is driven down it wants to turn the crankshaft. When the crankshaft turns, the propeller turns. To test the compression of the cylinder, we had to put 80 psi into the cylinder. So, essentially 80 pounds of force pushing down on that cylinder. That meant a brave soul had to hold the propeller in place. Paul and Philip gave did an example of the test on the first cylinder. Paul let the air in and Philip held the propeller. All went well. However, once 80 psi was put into the cylinder, we needed to see if it maintained that psi. The first cylinder ended up holding 64 psi. That means there was a leak somewhere down the line and it will need to be inspected later on. In order to pass the compression test, the cylinder cannot lose more than twenty-five percent of its compression, so ‘B1’ just passed. The rest were all passes, the majority loosing some compression out the exhaust ports.

Back to Paul putting the fear of God into me. With the 80 psi being forced into the cylinder, if that propeller was to let go or no one was there holding it, it would spin. Quite fast. So fast, that people have been seriously injured by it. By serious, I mean a nasty gash on the noggin, concussion, stitches, comas…(that’s the fear of God bit) bad news. You don’t want a smack from that prop that’s for sure.

So Paul’s holding the propeller, I plug in the air hose (my first time too), haven’t even turned it on (which we did slowly to gradually build the psi to 80) and I hear Paul, WOAH, WOAH, JEEZ, HEY, WOAH!?!?…I’m like OH S*@&! What??…Immediately begin turning the dial to relieve the pressure I haven’t even put in yet and shut the valve off thinking the gauge maybe malfunctioned? Then, perhaps having mercy on my state of horror and for his cruel joke, Paul told me all was ok, he was joking/testing, and good job for shutting the air off (but next time just disconnect the hose, it’s faster). So after a mild heart attack and a little laugh afterwards there were 10 more cylinders to check. Fortunately there weren’t 10 more heart attacks. Once the check was done, it was on to cleaning, replacing, and reconnecting the leads. Hat’s off to a job well done, if I don’t say so myself.

Now, apparently I forgot to include a picture of myself when I introduced myself 4 blogs prior. So to solve the mystery of the masked blogger, here he is (photo courtesy of Philip). That’s yours truly making the ladder look good/getting ready to test a cylinder on ‘A’ bank; now a seasoned veteran in the Compression test.

Smile for the camera Chris

Ask An AM-E?

As if I haven’t gone on long enough today, I want to include a small piece on an addition that I want to add to future blogs. This new section will be entitled “Ask An AM-E.” In this, I will take one reader submitted question and ask Paul Tremblay, the AM-E, your question. We will then try to figure out an appropriate answer. If your question is chosen, the answer to your question will appear in the following weeks blog at the tail end! Exciting stuff. Now, keep in mind, if a question is asked about the engine on an Air Bus A-380, you might not get an answer (or you’ll get a googled one). BUT if you ask anything about the Hurricane that interests you, the restoration process, being an AM-E, or working on the myriad of other Vintage Wings aircraft, I’m sure you’ll get a most excellent answer.

Questions can be emailed to me at “ceaton@vintagewings.ca”. I will only be able to answer one per week but if your question is not answered immediately, it could be answered in subsequent weeks! You may send me the same question as a reminder if it is not answered in a few weeks (who knows, I may be able to answer your question via email exchange!).

Well thanks for sticking it out to the end this week, I hope it has been an enlightening, exciting, and enjoyable read.

Until next time, take care!

Chris