Roost Air Lounge => The Classroom => Topic started by: Frank N. O. on November 18, 2007, 08:50:55 PM
Title: Request: Aircraft Piston Engines 101
Post by: Frank N. O. on November 18, 2007, 08:50:55 PM
Ok actually I'm not exactly sure what 101 means other that it's usually something written after US school classes so I figured it meant Level or something like that.
I know a fair bit about Otto-engines for cars, but what's the basic configuration of an aircraft engine and what needs to be adjusted regularly on it?
As far as I've picked up then an average aircraft piston engine is a flat-engine with a central camshaft and magneto ignition with two spark plugs per cylinder and air cooling, and some have carburators and others have fuel-injection (mechanical only I'd imagine), but what about the other aspects? Is it a single cylinderhead per bank or seperate per cylinder like Scania-trucks for instance? I can imagine there are only 2 valves per cylinder on any aircraft engine but are they overhead? Do they have mechanical valve-lifters that need periodic adjustment or are they service-free hydralic ones? Is the camshaft a std. or roller-type? Do they use cross-flow cylinderheads? What kind of firing order do they have? Like a boxer-engine or a V? (two at the same time or two pistons on the same part of he crankshaft giving more vibration, I can definately remember the Cardinal RG I flew in really shook hard when the engine stopped). Do they use wet or dry-sump lubrication and is there an oil-cooler? And do aircraft engines use oil-spray underneath the pistons to cool then down like some car-engines? Is it a mono or multi-point fuel-delivery? (one nozzle per cylinder or one for all). What does an average aircraft engine weigh?
Frank
Title: Re: Request: Aircraft Piston Engines 101
Post by: AirScorp on November 19, 2007, 01:49:15 AM
Frank, I always thought of 101 etc. like chapters in a book. First is chapter 1.01, then goes to 1.02, 1.03.. Then you go to a new "more advanced chapter" and start again 2.01, 3.01 etc. Then again, I'm Greek :)
As for your question, I'm like you so no real answers, what I do know is that most "simple" engines are dry-sump lubricated. That much I remember from the books..
Why not start at a place like http://en.wikipedia.org/wiki/List_of_aircraft_engines (http://en.wikipedia.org/wiki/List_of_aircraft_engines) and check out the Lycomings and Rotaxes for a start?
And remember, the smaller the airplane, the simpler the engine will be in most cases. Makes sense to be easy to maintain.
Title: Re: Request: Aircraft Piston Engines 101
Post by: BrianGMFS on November 19, 2007, 02:38:11 AM
While I'm not a Mechanic...... I do work in an aircraft repair shop. Most aircraft piston engines are horizontally opposed four or six cylinder powerplants. Each cylinder is a separate part. Much like a motorcycles air cooled engine or the old style VW Bug.
Here's a couple of shots showing the two extremes of aircraft engines. The first is an old tired Grumman Tiger in for major maintenance...
Title: Re: Request: Aircraft Piston Engines 101
Post by: Fabo on November 19, 2007, 01:55:47 PM
Me likes the first one the best ::loony:: ::rofl::
Title: Re: Request: Aircraft Piston Engines 101
Post by: airtac on November 19, 2007, 03:32:45 PM
Thing I noticed is what I look for when I take an airplane to have maintenence done---a clean shop |:)\
That Tiger, incidently, looks likes it's been rode hard and put away wet ::eek::
Title: Re: Request: Aircraft Piston Engines 101
Post by: PiperGirl on November 19, 2007, 04:38:51 PM
Nice clean shop there. It's always nice to see a clean area.
Title: Re: Request: Aircraft Piston Engines 101
Post by: BrianGMFS on November 20, 2007, 04:05:26 AM
Thanks for the comments on the hangar floor. One of my more "pain in the butt" jobs during the day is cleaning the hangar floor ::banghead:: The hangar is 120 feet by 100 feet. We have a walk behind floor scrubber that helps somewhat but it still can be a pain ::rofl:: I don't know how many times someone has come into the hangar as said how clean it looked and I look at it and say this is what we consider a dirty floor ::loony::
Here's a shot to show the size. in the shot is a Challenger, Citation Excel and a C-90 King Air with room for a few more planes (http://i6.photobucket.com/albums/y215/Brian_Gladden/Picture011.jpg)
or for those of you who know how big a DC-3 is in real life.... Plenty of room to spare (http://i6.photobucket.com/albums/y215/Brian_Gladden/DC-3.jpg)
That Tiger is pretty beat... it has only seen the inside of a hangar when it's getting worked on. This Annual is really gonna cost some $$$$
Brian
Title: Re: Request: Aircraft Piston Engines 101
Post by: undatc on November 20, 2007, 06:10:18 AM
Brand new cirrus and already in for work. ::banghead::
On the note about cirrus, I didn't know till about two weeks ago, one of their main plants is here in town. Had to deliver a pizza to their building.
Title: Re: Request: Aircraft Piston Engines 101
Post by: BrianGMFS on November 20, 2007, 02:14:17 PM
Quote
Brand new cirrus and already in for work.
Yep... Not Cirrus' fault.... I think the owner could grenade a lawnmower, let alone a turbo'd Continental. We've hung one complete engine (prop strike) and 3 cylinders on his Mooney 231 and so far one new jug on his Cirrus. The mechanics in the shop think he runs it WAYYY too lean and burns pistons.
Brian
Title: Re: Request: Aircraft Piston Engines 101
Post by: Rooster Cruiser on November 20, 2007, 03:34:31 PM
...The mechanics in the shop think he runs it WAYYY too lean and burns pistons.
Brian
This was exactly my thought when I saw the condition of the heat shroud around the turbo. The heat discoloring of the shroud indicates the operator is running it WAY too hot! I'm guessing he's thinking he's running lean of peak when in reality he's running it right at peak. that would explain burned up pistons and exhaust valves.
Running extra fuel through a turbocharged engine to keep the temps down is actually cheaper than replacing cylinders, etc. When it comes to peace of mind regarding how healthy your engine is on a single... it's PRICELESS!!!
Title: Re: Request: Aircraft Piston Engines 101
Post by: Mike on November 22, 2007, 05:39:15 PM
Hey Frank, to get back to the topic:
Here is a picture of a Cessna 172. (the closest I could find to a Cardinal)
Title: Re: Request: Aircraft Piston Engines 101
Post by: Mike on November 22, 2007, 05:56:44 PM
Let's just talk about what's in the little Cessnas for now:
A Lycoming engine is what they call "boxer motor" in Europe. The Americans call it horizontally opposed cylinders. For example a "O-360" means opposed cylinders, 360 cubic inches. an "IO-360" would be an injected engine w/ opposed cyl. . . . helicopters usually run HIO-360's and so on and so on . . . .
they are basically tractor engines from the 50's. Huge, but keep running.
Two sparkplugs in each cylinder, each plug runs of a different magneto. (one magneto runs the top two plugs on one side and the bottom two plugs on the other side) That helps the fuel burn better when they are both working and puts in redundnancy in case one magneto fails
They also have two mechanical vlaves in each cylinder. And, yes, they need to be checked and re-set periodically.
Each cylinder head can be removed and repaired individually. It's a very simple engine once you take a close look. There is no cylinder block. Since the engine is aircooled (needs fins around each one of them) you don't need one and this way you can fix individual cylinders pistons and rings without removing and replacing the whole engine.
Lubrication is what they call a dry sump I believe. The oil reservoir is in the bottom (square block, you can see it on the picture) and the oil gets sucked to the top, runs trough the cams and so on until it drips back into the reservoir. Yes, most have oil coolers, but the cylinders are aircooled.
The reason why the engine shook when it was shut down is a combination of the prop directly running of the driveshaft and this engine having a huge amount of cubic inches as compared to a European car.
Most of them have only one fuel nozzle per cylinder.
Did that answer all your questions? ::wave::
Title: Re: Request: Aircraft Piston Engines 101
Post by: Mike on November 22, 2007, 06:00:30 PM
the Tiger has two cylinders removed (at least on the left side) and on the top right you see the oil-cooler. in the front, underneath the ring-gear on the prop, you can see the starter
Title: Re: Request: Aircraft Piston Engines 101
Post by: Frank N. O. on November 22, 2007, 11:42:10 PM
Wow, great info there Mike, and what a cool illustration picture |:)\ It was also ok it wasn't a Cardinal since it was generally about piston engines, the note about the Cardinal was just for the shaking, but I'd thought it was because a boxer-engines cylinder's aren't exactly parallel seen from above so at low rpm it might do that.
I didn't know the classic Lycoming was based on a tractor engine, that almost completes the circle with Preston Tucker's classic Tucker Torpedo which had it's rear-mounted air-cooled flat-6 from a helicopter. The Dodge Viper V10 engine was of course derived from a Dodge pick-up engine and the Y2K Jet Bike uses a Rolls Royce Allison 250-series gasturbine from a helicopter. I've read that several ultra-lights use Mazda Wankel rotary engines and then of course there was the PFM, 'nuff said.
Frank
Title: Re: Request: Aircraft Piston Engines 101
Post by: Rooster Cruiser on November 23, 2007, 03:11:58 AM
If memory serves me, the flat, horizontally opposed, air cooled piston engine was originally designed for aircraft propulsion and patented by Dr Porsche around 1927. The design proved so reliable compared to other engine designs of the day, that when Herr Hitler decreed Germany would produce a "People's Car" or Volkswagon, the engineers selected Dr Porsche's design and modified it for automotive use. This was also due to the design's relative light weight and ease of maintenance as well as its reliability.
Title: Re: Request: Aircraft Piston Engines 101
Post by: Mike on November 23, 2007, 06:06:18 AM
ok, when I said they're old tractor engine, I was simply referring to the sturdy built, the huge cubic inches compared to their horse power, and the way they sound . . .
Title: Re: Request: Aircraft Piston Engines 101
Post by: Frank N. O. on November 23, 2007, 01:00:51 PM
Oh sorry, my mistake.
Frank
Title: Re: Request: Aircraft Piston Engines 101
Post by: BrianGMFS on November 23, 2007, 03:39:50 PM
the Tiger has two cylinders removed (at least on the left side) and on the top right you see the oil-cooler. in the front, underneath the ring-gear on the prop, you can see the starter
Actually it has all 4 Cylinders pulled.... Compressions were too low so it's getting new rings and pistons. There's a possibility that my company may buy this plane to fix up and use it as the company "hack". It's use would be for things like parts runs, flying a mechanic to another airport for a quick repair job and for anyone who works here to get their pilots licences. About 80% of our pilots are CFI's and we even have 2 FAA Check Airmen in house so that would be pretty nice, Almost like another benefit.
Brian
Title: Re: Request: Aircraft Piston Engines 101
Post by: Fabo on November 23, 2007, 08:52:56 PM
Back to Mikes nice writing about Boxer: not to forget to mention, this type of engine became, unsuprisingly, the standart of Ferdinands later car production - world-known Porsche brand.
Title: Re: Request: Aircraft Piston Engines 101
Post by: Franz on November 25, 2007, 08:47:53 PM
Of course, the large Lycomings and Continentals are the typical aircraft engines, but there are also some others. For example Rotax (http://en.wikipedia.org/wiki/Rotax) (smaller engines for light planes) and Thielert (http://en.wikipedia.org/wiki/Centurion_Engines) (diesel aircraft engines)
Maybe, when I have a little more time, I'll write more than just posting links to Wikipedia, but at the moment I'm quite busy with all kinds of school-related stuff.
