It has many names. The motor, the power plant, the fan... But by any measure it's really important! This week we are talking about the most important system on your airplane. The engine!! If you've got a checkride coming up, this week's episode is a must listen. Wally (DPE) walks through exactly what he's looking for as far as an understanding of the engine on your oral exam. Very valuable info on this week's episode of Behind The Prop!
What's the first thing you look at when you see a new aircraft? Definitely the paint. Maybe the panel. But buried under the cowling lies the airplane's most important system... the engine! This week Bobby & Wally delve into the basic components of the engine, as well as some basic things you can do to care for yours and keep it running smoothly.
Clear prop! Number two following twin traffic on 3 mile final. JB using runway 25 on a 4-mile final.
This is Behind the Prop with United Flight Systems owner and licensed pilot, Bobby Doss. and it's co-host: major airline captain Designated Pilot Examiner, Wally Mulhearn. Now let's go behind the prop!
What's up, Wally? Hey bobby, How are you? I’m doing great. this week Is another system probably most important system this week. We're going to talk about engines or ab commonly referred to as the power plant. Wally, you fly a lot of different planes a lot of different schools and a lot of different places. How important to you is the engine? And what do you think about when you think about set engines?
Well yeah, the engine is pretty doggone important and I’m just going to plug future episode. We In fact I’m going to let you plug it, bobby. Why don't you. You made the contact. Why don't you tell our listeners Who were going to have on our show here in a couple of weeks.
yes. So we reached out to Mike. Bush and Savvy aviation dot com. He is going to join us on the show and a few weeks and we're going to have a great systems conversation hopefully apart one of many parts and visits for mike bush. If you're not familiar with Mike Bush, Wally and I would refer to him Probably as the only famous mechanic in the world maybe probably so as it relates aviation so We can't wait to have mike pushing on the show. If you haven't listened to any of his stuff. Lots of books and lots of other podcasts and things. But we can't wait to have mike bush on the show and he'll probably teach all of us more about engines and things we need to learn. But we are excited to have him and we're excited to start the conversation this week as it relates to the power plant.
So we're going to we're just going to scratch the surface on engines here and when we when we talked to mike. We're going to get much more in depth than engines. But I’ll just tell a little story when I was looking for a six-place airplane Several years ago I put I came up with three categories. And I first of all I set a budget I said okay I want to spend this much money. Or I don't want to spend more than this much money on an airplane. and I went through and I said okay. I'm going to look at airplanes. I'm going to look at painting Interior as one area. I'm going to look at avionics as another area. And I’m going to look at the engine as another area. so I wanted An airplane had good paint and interior good avionics and a good engine. And I quickly found that the budget that I had set that I was not going to find an airplane that Put a checkmark by all three of those. I can get good painting interior. I could get good avionics. But I was going to have a very high time engine or I could get You know a mid-time to low time mention with good avionics but it needed painting interior. and the one thing I did not want to do on I bought an airplane. I didn't want to buy an airplane and bring it home and immediately put it in the shop for a prolonged period of time. So what did I do? I up my budget. And I found that airplane that met all three of the requirements. But I think when we when we look at airplanes physically when we see an airplane on the ramp the first thing, we probably see is the paint and that's the first appeal to it. Wow that's a really nice paint job. And I’m not talking about an exotic Paint scheme. I've seen airplanes That are white with black numbers. And I can look at it and say that's a really nice job it looks good. It's good paint or you know it's not chipping or anything and that kind of stuff. So I’m not talking about a fancy paint scheme per se. I'm just talking about a nice, good paint job. So I think that's the first thing that we look at And as I. I don't know about most of listeners but I know what I do is I’ll look up to, I'll walk up to an airplane and I peak in the peak in the window and then the next thing I probably see is the interior. Wow boy it's got nice leather interior. It's got the dull the logo on the headrests of the weather. A Beechcraft piper or Cessna or whatever cirrus. And then the next thing I do is I look up at the panel. Oh wow yeah. It's got a nice whatever system in it And we forget about the engine you know most. I've obviously you're not going to go up to a stranger's airplane the cowling and start looking at the engine but the fact of the matter is I’ve flown many airplanes.
That have bad paint jobs. And they fly just fine Flown airplanes that have very dated avionics and they fly just fine. Probably the most important thing of those three areas that I mentioned is the engine and it's probably forgotten. I mean a bad engine is going to probably result in a bad flight. so Something that that we need to think about, And a high time engine doesn't meet a mean a bad engine. You know, mike bush is going to talk about this a lot and a couple of episodes. I think I know many of his Webinars I’ve listened to. He does talk about flying airplanes beyond tbo But then I let him talk about that. but obviously without an engine, the airplane is not going to fly. So it's probably the most important question.
No question; and so I think I think the understanding of it is key and that's really what we want to try and help everybody with today and I think there's varying needs of understanding, but as a private pilot student You need to understand what's going on what's creating and producing the power. I joked with Wally before we started recording, I can remember memorizing the first two paragraphs of the POH about the description of the engine. It's a Lycoming. It's an opposing engine. And but I didn't really know what any of that meant I just knew that. If I got asked him, I check ride oral I needed to be able to talk about the engine a little bit and that. That's probably where most of us are at and if you're beyond that great, But I think as I became an instrument pilot, and I bought a flight school, and learn more and more, I understood the importance of understanding What's going on. Because there's a lot of I guess points of redundancy but those create points of failure and most points a failure don't mean that you're going to have a really bad day. it just means you need understand what to do about that point of failure. And how serious is at point of failure and I think the better and smarter you get the more confident you get as a pilot. The more the you can you can take on as a pilot in the cockpit and understand What's going on. So let's talk through those things at a really high level we're going to talk about the basics for a little bit. There's a lot of components. and so if you think about all the things under the cowing there's obviously an engine in the components that make up that engine. There's a case, Which is the true poured block of that engine and their cylinders, And there's pistons and there's vows and push rods; There's a whole bunch of components, but we're going to assume that that camshaft and crankshaft and all that stuff together and we're not going to talk about each of those individual components today. because that that could go on and on that would be an engines class not necessarily podcast. And then on top of that around that engine There's a lot of other things and we've done episode on some of those like the ignition system. That ignition system has magnetos, and spark plugs and wires and a starter and an ignition switch. A whole separate system. We've done shows on those There you could say the electrical system the vacuum system the exhaust system the heater system. All those are kind of tied into around the engine. Not necessarily what We're going to dive deeper in into today. We want to talk about really What makes that power plant create power and how do we diagnose if we have a problem with power plant. So let's jump right In I think the key is that those the pistons inside the cylinders going up and down and they're creating power right and yeah most of what we're talking about a really all we're talking about today or the common general aviation four-cylinder Lycoming engines That are out there now. Guess one thing of the verge to here's these are really basic engines. These you put a nineteen seventy-eight Cessna next to a two thousand twenty Cessna, ones probably carbureted engine and ones fuel injected the engines probably really similar underneath the quote unquote hood. You put a nineteen seventy-eight chevy pickup truck next to a two thousand chevy pickup truck, They're going to be very different. Absolutely. why I mean, Hopefully we know the answer. But why are they so different. Wally? What's kept one back from the other well with a car.
I mean we got all kinds of computers in there you know and computer I don't know you know monitors.
Yeah, and airplanes And again I keep referring to Mike Bush because he's going to talk about this a lot. You know how airplane engine Technology has not advanced near as much as car technology has advanced. You know the technology of most aircraft engines today is probably nineteen forties technology.
and the reason the short answer in my opinion for all that is the faa. Yeah, it's the regulation. Yeah, like cars Spend a lot of money to just to get the regulations covered. But I mean the how. I'm not sure it's faulting them because they're trying to keep us safe, but the faa it is so freaking hard. you look at the non-regulated experimental aircraft that are that are out there, They've got newer Better stuff. But you can't train 'em you can't have pat you know there's lots of regulations around an experimental aircraft but that's avionics and engines and all that stuff but yeah. They're pretty similar over the last, You know forty years those engines are going to be identical in Cessnas for the most part, no question. yes, and so those four-cylinder engines that are super redundant and have all the of the great capabilities. We need to stay in the air. is why they haven't changed and then regulations are why them saints. But there's four strokes so that cylinder goes up and down in in in four strokes to create power. And I guess without visuals here. We'll talk kind of a little bit of what's going on inside of each cylinder think of a round cylinder that the top of that. There's two spark plugs that come from two from both magnetos. We've had a show on that and that's cylinder goes down. There's two valves. Also the top of that cylinder one valve opens and then the cylinder piston goes down and it pulls in the air gas mixture. The air fuel mixture that we would have a in that aircraft for that day. and as it comes back up. It's creating compression. It's the compression stroke which takes all that and makes it get into a really small area, and then the to spark plugs assuming both magnetos are working, fire and they stood in that piston back down. Which is the power stroke and then as it comes back up. The other valve opens while keeping the other one closed. Which is the exhaust valve sending that exhaust out through the exhaust system. and so those four strokes happening simultaneously in all four pistons, cylinders and that creates power which turns the crankshaft which then in turn turns the prop which creates air to move the aircraft. Right, right. so hopefully we did a good job there Without visuals but if you think about the engine the cylinders are opposing each other. So they're kind of pointing out sideways And that kind of helps the balance, and the torque, and all those things that are going on and they turned that prop which makes continues make power but if you think about these four cylinders each of those four cylinders are simultaneously at a different stroke of those four strokes. ones creating power ones creating intake once craig impression and once creating exhaust. and they're going really fast, right Wally? this is not something while on a YouTube video you might see them happening slowly. They're happening really fast. if yes think that The crankshaft is turning at twenty-three hundred Rpm per minute. I had this. Ah mathur but that. That's a lot of strokes per second. Yes absolutely. It's really really really really turning.
And so you know the designation of the engine. Let's take an oh three twenty that oh in front of the three twenty actually means something and what it stands for is opposed. means The cylinders are opposite of each other Those letters in front of an engine designation; There's four that we probably three that we see a lot. Sometimes we'll see an io in io three sixty. Or what is the I stand for the ice dance for injected in other words ascension is fuel injected. So right off the bat I know I’m not going to have carburetor. I don't have a carburetor. So fuel injected engine And then you may see a t- which means it's charged My Saratoga has a tio five forty so it's a turbocharged fuel injected and a post so Those letters actually do mean something. so in an airplane when we have a rough running engine It is probably because the engine is essentially out of balance, per se. One of the cylinders is probably or one of the pistons inside
The cylinder is probably not firing are moving like the one on the opposite side is and that's probably what's causing the the the airplane to run rough. so We see this on mag checks where we go out and we were doing our run up and we shut the mag We shut one mag at a time off and essentially were shutting half of the spark plugs one spark sparkplug from each cylinder off so we have a bad spark plug, maybe One cylinder is not performing properly. That's why we get the rough running engine, because basically engine out of balance.
so you mentioned there were four letters. The other letter is s. that stands for supercharge. Probably not going to see that at your local flight school anytime soon. I'm just going to call that out. But there is a fourth letter there and it's s so talk about, you said five forty most of the one seventy twos on our flight line at the flight school Here, All have three twenty. So what's the difference between a five forty and a three twenty, And what do you What do you think of when you hear those numbers?
The Three twenty is the displacement. It's three twenty Cubic inches and three sixty would be three hundred sixty. It works out to where the horsepower avenge of the engine is usually About half of the displacement so an oath three twenty is usually one hundred sixty horsepower Engine, or about. Now in the case of Saratoga tio five forty at half a five forty-eight to seventy but it does have a three hundred horsepower engine but that could be attributed to the turbocharger adds a little bit of extra power. But you know an I o three sixty Most archers piper archers have an I o three sixty maybe an oath three sixty hundred and eighty horsepower engine so you can get an idea of what the horse power is by just looking at that designation.
so we talked About the four strokes in the engine. We talked about the identifiers of those engines. You probably assume during private pilots checkrides Ask your candidates questions about the engine. What what are you looking for in their understanding of an engine, if you if you could share with us a little bit. not necessarily exactly what the answer needs to be. But what are you looking for as it relates to their understanding of the engine or powerplant?
Yeah, I’m going to ask them questions In a scenario base situation. I may ask them about if you know if during the run-up You had a rough running engine, What would you do? And of course the these answer and what most people give me as long to taxi back in and having mechanic look at it and I go well okay you could do that. And I can't say that's wrong But I say well let Let's say you're at an airport where you don't have that available to you and usually the next thing is they say. Well I’ll cancel the flight and so Well we try to get into is you know at that point. We'll talk about how many cylinders we have on the airplane. And how many sparkplugs we have in the airplane. How many magnetos does and what What's actually going on inside that engine. I don't I get super involved in things. But I think it is important that we kind of know what is going on inside the engine and The reason why the engine is running rough. Why, Why is the airplane running rough right now?
So they don't need a big mechanic. Of course no need to have some knowledge about reading the POH assumes probably enough and yeah the articulate some of the components. common problems We start a lot of engines. I would say the biggest thing that people struggle with is the starting of the engine we at home probably start our vehicles every day and never have any trouble when we do. It's very unlikely. We're going to pop the hood and figure it out on own. maybe when I was in high school, That was possible with a little bit of trips to high low auto parts which doesn't exist anymore. Yeah, but today. In in an aircraft's there's twelve on my line out there. They're all probably going to start multiple times today. People struggle starting aircraft.
Why do People struggle starting aircraft?
Well one thing versus your car is most cars are going to have nice electronic ignition systems. Modern ignition systems and in these airplanes, literally, We have nineteen twenty technology. for most of these airplanes we have magney does and We don't have a nice electronic ignition system that goes to the and at some airplanes are going to an electronic ignition system and and experimental airplanes all most of them probably have it. And so there's a lot of lot of pull push and pull with the faa trying to get them to allow us to use more of electronic ignition system. That's that's an argument for another day. And that's against something I keep referring to Mike Bush but something. He's very passionate about is electric ignition system. So that's part of the problem is just the ignition system and by definition the ignition system is what excites the engine right and keeps it running. The other thing is A lot of these airplanes have carburetors rather than fuel injected. so that’s another Maybe more complex System of mixing the fuel and air.
Yes so there's really three types of starting an engine hot, cold and flooded. All should be referenced in your POH for the type of aircraft that you're flying on any given day but we're talking generalities here a Lycoming. Three sixty-three twenty. Four cylinder opposing ends in a piper or Cessna product is probably going to start fairly similarly if it's carbureted or its fuel injected based on a hot, cold, or flooded start. meaning fuel injected one type of problem carbonated one. A problem Most commonly lesson after less than after lesson these engines are or hot or very warm for the from the flight prior to and we think of a hot start quite a bit. so A hot start is much harder in a fuel injected aircraft than it is in a carbonated aircraft. And I think has to do If you read your POH probably talks about it but the heat vaporizes the fuel in the fuel lines going into the injection system and you really have to try and start The plane with the mixture pulled all the way out and just a little bit a throttle. And really what you're doing as you're cranking That engine is clear. Clearing that vapor out of those lines to then get fuel to get to the cylinders and vaporize there. And probably the common mistake is too much of that red pushed in While you're trying to start that aircraft warm or hot. And then the carburetor engines probably easier to start When it's hot but you just don't want to over prime it at that point right you put a whole lot of fuel those cylinders you might flood it. We'll talk about that as the second. Yeah we just went through the coldest time probably ever in the city of Houston. Both experienced our own woes as it would relate to water broken pipes and frozen this in the area Not a lot of flying going on. but man cold starts. My maintenance manager gets real agitated real quick because they try and they try and they try to take all the juice out of those batteries right. any tips for a cold start?
You know I when I when I got my Saratoga. The guy that sold it to me We went out. We fluid for about an hour and he said okay. Well here's how you start it. We got in and it started right up and so I was flying at home we to make fuel stop on the way home and I got back in the airplane and that airplane not start. I was doing it the way he told me to start it. And then I finally got smart. Actually pulled out the POH. And I did the procedure in the POH. And the airplanes started right up. So that's where I would start is start. Start with the POH. it seems kind of ridiculous that I’m having to say that but I would look in the mirror and say I was guilty of trying to come up with another way to start it and the POH works.
That’s why the maintenance manager is always upset. He's like the come in the batteries dead. They need a jump and he's like did you read the POH not to start right. It's right there for you. Yeah it's not going to be like last Saturday when it was ninety degrees.
Yeah and I. And I know in in in my airplane The Saratoga you know it is a big bore engine and it is fuel injected. A cold start is actually fairly easy. Well they're very easy If I shut down the airplane for five minutes,
I can get in and it's not a problem. The start where kind of run into The problem is the time when it's shut down for about forty-five minutes and what's that that's a fuel stop that's you you're stopping somewhere to get fuel. You go in, use the bathroom, You pay your bill. That's usually about forty-five minutes, And that's the time. that It's taken me a couple of years. But I’ve now at I’m pretty good. Getting the airplanes started. But it's kind of embarrassing when you're out on the ramp trying to start the engine and You know the line guy standing in front of you telling you you're clear to start near saying well I’m trying to start; It's just not starting.
so on a cold start. I think the tip again. Look at the But it's probably harder to start a carburetor engine as you said a fuel injected engine probably fairly easy to start when it's cold but a carburetor engine is more difficult. and the reason for that is the fuel air ratio or the mixture And what that really needs so very dense air needs lots of fuel. and the common mistake might be over priming in a situation but you and it is probably an art You probably not going to get it if you have Five hours of flight time. but A little bit more fuel and a little bit more mixture or you got to really trying to get that mixture balanced to where the engine can start. So, if you don't private excessively then you need to probably take some of that mixture out And there's there is a setting on the carburetor of the fuel air mixture that set. That you really can't change unless you change the throttle characteristic so you might have to have a little bit throttle and a little bit of mixture out it becomes the science. but if you can think about my putting enough fuel in that cylinder That's getting some spark with the dense air today. That's really what you're trying to get to on a cold Start to get that engine fire up on carbonated engine.
flooded start. We've all been there We've probably all flooded an engine in our days On the flight line so the gym comes flooded. The answer simply again: check your POH. Ph but probably most Cessnas and warriors Call for the engine The well the fuel system to be set up as much as having a completely full throttle and a completely mixture pulled out. Or no mixture I guess would be the words. and what you're going to do is start cranking that engine and as it starts to start you're going to take and pull the throttle back and push the mixture in Which is going to get the balances right. and that never made sense to me. Which kind of brings us to the last topic you know. What are these levers controlling? what are we What are we doing? So when I have the full throttle fully in. It's not called the fuel. I'm pushing the fuel all the way in and pushing the throttle all the way. and so a carbonated engine, I'm really opening that dampers valve. I guess at the top of the car raider that lets that fuel air ratio flush itself to the right so. and that probably if you look it up. It's probably one to fifteen parts One part fuel fifteen parts air. It's flooding through the carburetor the throttles wide open and stop sucking and all that air and all that that little bits of fuel and then based on the mixture the red knob, im Able to control. What am I Controlling there, Wally, with that red knob? I think a lot of people. It's called the mixture is it. Is it air or fuel or combination of both what am controlling?
You’re controlling fuel with that with that red knob.
Yeah so it. Is the fuel amount that is going in a cylinder so I think I’ve heard people reference it as you know, I'm controlling the amount of air. That's not the case. You're leaning at three thousand feet and above in most cases. Because the air density is less up there and I need less fuel so as I back out that red knob on backing out the fuel. That's going into that system or that cylinder. so if I have a flooded engine I want the throttle wide open and I want that amount of fuel going in there to be less I pull the red knob out and I think just little bit of learnings like that will make you a much better pilot, as well. so I hope we've helped explain the engine, What's going on in the engine with the four strokes are what some of the letters and numbers me around the engine. We can't wait to If you've never met, Listen any Mike Bush stuff in addition and Mr. Mike Bush and savvy aviation in a couple of weeks anything to wrap while we as we wrap up today on engines?
No we're good just You know don't forget about that. Engine you know some of it. Some of the older pipers Have cowlings that you can actually open up in a preflight.
And I’m so I so wish we could do that on more airplanes. Because you know most Cessnas you got a little thing that we open up and we reach in there and can't really even see but we reach in there and pull out the oil dipstick and maybe drain a sump- But we don't really get a very good look on it. so my know my courage would be to When you're at your flight school are at an FBO, And they've got an engine on cow. Go out there and take a look at it.
That's a great point. My mechanic at this airfield would love for people to visit and look inside cowlings every time. My twin is in a hundred hour. Or an annual. I love to go down there while it’s on jacks. The seats are off. You can watch the gear and all the things going on like there's great opportunities to do that. But you're going to have to be proactive. There's never you can't be ever too smart on systems as it relates to these aircraft and there's always another aircraft that you can learn something about a system that you're not familiar with. so go Challenge yourself, get to your mechanic, and check out some of the things that are under the cowing and under those seats you'll really become smarter and a much better pilot as you do so. as always thanks for listening, Please share with a friend, Please give us five stars wherever you Listen to podcasts as we have earned it and as always stay behind the prop.
Thanks for listening. Thanks for checking out the Behind The Prop podcast. be sure to click subscribe and check us out online at BehindTheProp.com behind the prop is recorded in Houston, Texas. Show creator and host is Bobby Doss. Co-host is Wally Mulhearn. This shoe is for entertainment purposes Only. and not meant to replace actual flight instruction. Thanks for listening and remember: fly safe!