How A Radial Engine Works

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Darrell
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How A Radial Engine Works

Postby Darrell » Mon Jan 25, 2016 2:05 am

Parts 1 & 2:

https://www.youtube.com/watch?v=qjnQKXNPsk4

https://www.youtube.com/watch?v=R71Xhrkc3EQ

Fascinating! Seems like it would produce a lot of torque. Shamelessly stolen from an arfcom thread. 8-)
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Re: How A Radial Engine Works

Postby JustinR » Mon Jan 25, 2016 3:01 am

That is awesome. I mostly understood the concepts from my reading, but I am a visual learner and that helps to put it together. Thanks for sharing.
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Re: How A Radial Engine Works

Postby mekender » Mon Jan 25, 2016 4:47 am

Certainly interesting, I had always thought that the outer part with the pistons was what rotated.
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Re: How A Radial Engine Works

Postby Captain Wheelgun » Mon Jan 25, 2016 6:58 am

mekender wrote:Certainly interesting, I had always thought that the outer part with the pistons was what rotated.

Nope, that's a Rotary engine (not to be confused with a Wankel engine). Rotaries are what you saw on most of the WW1 fighters. A lot of the mechanism is the same, but a rotary has the crankshaft bolted to the airplane and the propeller bolted to the crankcase, which turned with the cylinders. This allowed for adequate cooling at very low airspeeds, but was apparently a pain in the behind to throttle and has massive gyroscopic torque.
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Re: How A Radial Engine Works

Postby tfbncc » Mon Jan 25, 2016 3:15 pm

Certainly interesting, I had always thought that the outer part with the pistons was what rotated.


Well, you're not completely wrong. The Fokker DR1 Triplane used a rotary engine that the cylinders spun and the crank shaft was stationary. The major problem with this was that there was no throttle control. It was either on or off. The pilot slowed the airplane down by switching off the magnetos momentarily until he reached his desired speed. Not very efficient and it was one of the leading causes why the DR1 was replaced by the DR7 as the frontline scout of WWI

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Re: How A Radial Engine Works

Postby blackeagle603 » Mon Jan 25, 2016 3:28 pm

Yeah, word is that with a rotary if you want to turn left you're better off making a 270 to the right. Those were fed a fuel/oil mix thru the crankshaft (to deal with fuel delivery/plumbing challenge I imagine). Forget your dry sump, those were total loss oilers.
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Re: How A Radial Engine Works

Postby blackeagle603 » Mon Jan 25, 2016 3:36 pm

Interesting wiki on rotaries here: https://en.wikipedia.org/wiki/Rotary_engine
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Re: How A Radial Engine Works

Postby Greg » Mon Jan 25, 2016 3:44 pm

Captain Wheelgun wrote:
mekender wrote:Certainly interesting, I had always thought that the outer part with the pistons was what rotated.

Nope, that's a Rotary engine (not to be confused with a Wankel engine). Rotaries are what you saw on most of the WW1 fighters. A lot of the mechanism is the same, but a rotary has the crankshaft bolted to the airplane and the propeller bolted to the crankcase, which turned with the cylinders. This allowed for adequate cooling at very low airspeeds, but was apparently a pain in the behind to throttle and has massive gyroscopic torque.


Apparently there were a few different ways to modulate power output, but none of them was particularly satisfactory.

Also getting fuel and air into the cylinders is an issue, requiring the crankcase to serve as intake manifold. That has problematic consequences of its own, oil loss being only one of them.

Just as a side note, rotary engines are spectacularly loud for their power output.
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Re: How A Radial Engine Works

Postby mekender » Mon Jan 25, 2016 5:34 pm

blackeagle603 wrote:Interesting wiki on rotaries here: https://en.wikipedia.org/wiki/Rotary_engine


The animation on the right is what I remember seeing years ago that made me think that radials were like that... I never put 2 and 2 together to realize they were different designs.

Thinking about it logically for a split second, it makes total sense to do it the radial way, but it was not something I had ever really given a ton of thought to.

And I believe that there were some cars that had a rotary engine too...
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Re: How A Radial Engine Works

Postby randy » Mon Jan 25, 2016 6:44 pm

mekender wrote:And I believe that there were some cars that had a rotary engine too...


"...but the Mazda goes mmm..."
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Re: How A Radial Engine Works

Postby Captain Wheelgun » Mon Jan 25, 2016 6:56 pm

mekender wrote:
blackeagle603 wrote:Interesting wiki on rotaries here: https://en.wikipedia.org/wiki/Rotary_engine

Snip....

And I believe that there were some cars that had a rotary engine too...

I don't know about cars with rotaries, but if you look at the mechanical details, a Harley engine is effectively a two cylinder radial. Which is why both Harleys and radial engine airplanes sound so cool. :geek:
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Re: How A Radial Engine Works

Postby mekender » Mon Jan 25, 2016 9:04 pm

Captain Wheelgun wrote:
mekender wrote:
blackeagle603 wrote:Interesting wiki on rotaries here: https://en.wikipedia.org/wiki/Rotary_engine

Snip....

And I believe that there were some cars that had a rotary engine too...

I don't know about cars with rotaries, but if you look at the mechanical details, a Harley engine is effectively a two cylinder radial. Which is why both Harleys and radial engine airplanes sound so cool. :geek:


I actually saw it on a TV show a while back, older car, probably pre-WWII...

Ayup, found one... It was an Adams:

https://youtu.be/tZmd7k33JWE
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Re: How A Radial Engine Works

Postby Captain Wheelgun » Mon Jan 25, 2016 9:33 pm

mekender wrote:
Captain Wheelgun wrote:
mekender wrote:
blackeagle603 wrote:Interesting wiki on rotaries here: https://en.wikipedia.org/wiki/Rotary_engine

Snip....

And I believe that there were some cars that had a rotary engine too...

I don't know about cars with rotaries, but if you look at the mechanical details, a Harley engine is effectively a two cylinder radial. Which is why both Harleys and radial engine airplanes sound so cool. :geek:


I actually saw it on a TV show a while back, older car, probably pre-WWII...

Ayup, found one... It was an Adams:

https://youtu.be/tZmd7k33JWE


Arte Johnson wrote:Verrrry Interestink


Huh, you learn something every day. Since the engine turns counter-clockwise, I wonder if it was easier to make right turns than left turns, Like BE603 mentioned with rotary engine planes?
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Re: How A Radial Engine Works

Postby mekender » Tue Jan 26, 2016 3:55 am

Captain Wheelgun wrote:Huh, you learn something every day. Since the engine turns counter-clockwise, I wonder if it was easier to make right turns than left turns, Like BE603 mentioned with rotary engine planes?



I have to wonder if such a device would have meant a smoother ride than other contemporary vehicles given that they were far before modern suspensions?

The gyroscopic effect of such a large mass must have been immense.

Of course, the vibration of the engine may have offset that.
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Re: How A Radial Engine Works

Postby Denis » Tue Jan 26, 2016 8:22 am

randy wrote:
mekender wrote:And I believe that there were some cars that had a rotary engine too...


"...but the Mazda goes mmm..."


Priceless. Be sure to read all the comments on the YT link. There are very funny parody lyrics...

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Re: How A Radial Engine Works

Postby toad » Wed Jan 27, 2016 11:21 am

I always enjoyed the story about the French pilot who flew a Rotary engine fighter. An early Spad IIRC. Anyway the castor oil used for engine lube really, really got to him. So he had a hole cut into his trousers, one in his seat, and through the bottom of the fuselage. " I try to hold it till I'm over the German lines." It must of been fun for the mechanics, they had to drain the castor oil out of the engine while it was still hot, otherwise a complete tear down was necessary. Then there was probably some feces splatter on the aircraft. Ah nothing smells like a burning mechanic and hot used castor oil in the afternoon.

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Re: How A Radial Engine Works

Postby Old Grafton » Wed Jan 27, 2016 2:49 pm

Castor oil gels after being heated and cooled, thus the need to drain while hot. Mechanics reheated the oil using various methods and dumped it back in the engines pre-mission. For a marvelous view of the internal workings of a radial engine the Mighty Eighth Air Fore Museum in in suburban Savannah( Pooler) Georgia has a stunning motorized cutaway of a P&W R 2800(IIRC) that made my eyeballs ache just trying to watch all the clockworks churning in that thing.

And the rest of the Museum is an awesome place, too!!
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Re: How A Radial Engine Works

Postby Netpackrat » Wed Jan 27, 2016 2:55 pm

To this day, many aircraft mechanics still keep a small bottle of castor oil in their toolbox or line bag.
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Re: How A Radial Engine Works

Postby Denis » Wed Jan 27, 2016 3:22 pm

Netpackrat wrote:To this day, many aircraft mechanics still keep a small bottle of castor oil in their toolbox or line bag.


I wasn't aware that constipation was a professional problem for aircraft mechanics. :mrgreen:

Castor oil is a great case lube for resizing brass when reloading, BTW, much better than aalox, sprays and such. Just don't lick your fingers...

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Re: How A Radial Engine Works

Postby Netpackrat » Wed Jan 27, 2016 6:25 pm

Denis wrote:I wasn't aware that constipation was a professional problem for aircraft mechanics. :mrgreen:


Skydrol in the eyes can be.
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Re: How A Radial Engine Works

Postby Denis » Wed Jan 27, 2016 6:53 pm

Netpackrat wrote:
Denis wrote:I wasn't aware that constipation was a professional problem for aircraft mechanics. :mrgreen:


Skydrol in the eyes can be.


I had to look that up in WP:

Skydrol fluids are irritating to human tissue. Gloves and goggles are recommended safety equipment when servicing Skydrol systems. If the fluid gets on the skin it creates an itchy, red rash with a burning sensation which feels similar to a sunburn. The effects subside within a few hours and castor oil can be applied to the affected area to neutralize the burning.


Does castor oil in the eyes help, or just on affected skin?

Hah, apparently castor oil works on eyes too:

http://www.airliners.net/aviation-forum ... main/19582

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Re: How A Radial Engine Works

Postby toad » Thu Jan 28, 2016 12:09 pm

Fokker Aircraft built short haul twin turboprop aircraft. I think the first of the series was the F-27 Friendship. It used pneumatics for landing gear and brakes IIRC. Apparently they didn't have trouble with it. Must be nice not to have the "dribbles" under the mains anyway.
Skydrol sounds like it would be good for soaking gun parts in to remove carbon.
I like the all electric set up on the MU-200. I wonder if that could be up scaled for commuter aircraft?

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Re: How A Radial Engine Works

Postby Denis » Fri Jan 29, 2016 1:43 pm

toad wrote:Fokker Aircraft built short haul twin turboprop aircraft.


A humourous, but very learned, engineer of my acquaintance was retained by an airline to evaluate aircraft in which it was considering investing. Fokker was one potential supplier, so he frequently had to visit their premises. He gleefully and at every opportunity declared to all and sundry, "I'm off now to see the Fokkers!" :mrgreen:

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Re: How A Radial Engine Works

Postby randy » Fri Jan 29, 2016 6:59 pm

I remember one of Harlan Ellison's books had a series of NSFW King Kong cartoons. One was of Kong on top of the Empire State Building shaking his fist and yelling "Fokkers!"
...even before I read MHI, my response to seeing a poster for the stars of the latest Twilight movies was "I see 2 targets and a collaborator".


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