Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: Wilbus on May 21, 2002, 03:10:56 AM
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What's the real difference?
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Wilbuz, i think the main difference ist that an inline is almost everytime an liquid cooled engine, while the radial is an aircooled one.
Also inlines can be fittet into a longer but more streamline housing while an radial has more often larger frontal area that leads to greater drag.
Also radials can substain more battledamage (cause most often they dont have a vulnurable cooling system).
And last but not least it's a matter of personal taste, it's the same as if you want an V6 in your car or a line 6. :D
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Radials air-cooled and inlines water-cooled.
Radials have always "unpaired" numbers of cylinders in a row (7 or 9) when ww2 inlines had usually 12 or sometime even 24. Napier Sabre (Typhoon, Tempest) was built in H-configuration, you might think it as a two 12cyl boxer-engines stacked one above another.
There was also samekind X-engine, four inline cyl-blocks using one crankshaft.
was that enough ?
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Thanks both :)
Just a question Staga, what do you mean with "unpaired", they sat one by one or what? Looking at an F4u engine on a picture, they all sit in around the enringe in a circle, 2 rows I think, 9 in each, is that what you mean?
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i think stage means that aircooled hat odd numbers in a row like 5,7,9,11 and so on, while inlines had even numbers like 8,10,12 and so on.
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Hardly know anything about engines at all. Take the 190 engine, in sweden it's called "stjärn motor", Freely translated that means "star engine" because the cylinders are put in a star (all around as in a circle, like on the Boeing Stearman). Is this in a row or what?
Are ALL radials like that? Cylinders in a circle?
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let reformulate wilbus's question :
Blonde or brunette ?
hmmmm ...
that's truly an hard question ...
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Inline........never heard of it.:D :D
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Check this (http://216.219.216.110/engines/radial.htm) out about radial engine.
(http://www.cke-tech.com/graphics/Animation/40°by18°v-re-anim-th.gif)
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It's not the hair straffo, it's the "big blue eyes" ;)
That is a difficult question though :)
Thanks link, reading now (ok not now, typing but soon).
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Yes Xjazz! That is what I ment about "star engine" all in a sort of circle :)
Thanks :)
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AFAIK, radials use odd numbers of cylinders per circle as to under no circumstance have TWO cylinders pushing/pulling on the central rod in opposing directions (There is no 180 degree angle 'tween two cylinders, vector addition does the rest for u) This would damage the rod, and some inline engines (dunno about the WW2 ones) were able to produce such a direct-opposition condition with fatal results to the drive train (is that the correct word ?)
Also, inlines are liquid-cooled while ww2 radials were air-cooled, as has been pointed out above.
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A long-time friend and former AVG member (Flying Tigers), Erik Shilling, used to go ballistic whenever anyone would describe his beloved Curtiss Tomahawk (P-40) as having an "inline" engine.
"A Chrysler Slant-6 is an inline engine. the P-40 had a V-12!"
BTW, Erik passed away several weeks ago after a long term fight with cancer. He is greatly missed.
My regards,
Widewing
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It's easy: cylinders, valves etc. in line = inline :)
btw did you know a boxer-engine (=180 degree angle between cyl-blocks, like in old beetle and Subarus) could be called as a V engine in some cases ?
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No idea Staga, I know zip about engines :)
Any info welcome, don't even understand all you're saying about it :(
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Another interesting engine. (http://www.wpafb.af.mil/museum/engines/eng3.htm) The Allison V-3420 24-cylinder double-v or W. Much like the Sabre but a little different cylinder arrangement.
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In general terms:
radial engine advantages:
-Lighter weight per HP- no heavy cooling systems
-relative simplicity and durability
Disadvantages:
-Large frontal area to give every cylinder equal airflow
-Large cooling drag penalty from moving a large volume of air through the cowl or nacelle.
In-line, or vee advantages: (liquid cooled only)
-Higher combustion temps possible, so more power per cubic inch
-narrow, low-drag profile
disadvantages:
-Heavy, complex cooling system that has radiatiors, which impart their own large drag penalty unless the designer is very clever.
by the end of the war, I think it was agreed that neither configuration was totally superior. Both engines were developed to high levels, and placed on highly developed fighters.
Just my own thoughts, though.
-Vspeed
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"BTW, Erik passed away several weeks ago after a long term fight with cancer. He is greatly missed.
My regards,
Widewing"
Damm!:(
If you ever had the chance to exchange messages with him, you know we lost one of the few people "who were there" that was willing to talk with the public at large.
He was nice enough to answer some questions I had on the C.W. Demon. In his writings to me he was every bit the gentleman. If your last name was the same as a certain American car company, it was a different thing.
Now I know what markings I want on the A.V.G. Hawk.
Rest in peace, and thanks from me for your service...
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Some old Ferrari 12-cyl boxers (Flat-12s) can be described as a V-engines because engine's crankshaft's "knees" (for connecting rods) and ignition timing were arranged similar way like in V-engines and not like they usually are in flat engines.
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Originally posted by Naudet
i think stage means that aircooled hat odd numbers in a row like 5,7,9,11 and so on, while inlines had even numbers like 8,10,12 and so on.
BTW
Audi had (have?) inline 5 car engine which runs very smoothly.
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Yeah, and Suzuki and Daihatsu had 3cyl engines too which btw had a very nice sounds. I believe first 5cyl engine was used in old Mercedes-Benz 300 diesel in late seventies AFAIR.
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Yep, Mercedes OM617.912 used in early 300D's, came in Feb.1976.
I'm not sure if there were some earlier car engines with odd numbers of cyls.
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Yes i know that 5 cylinder inlines too.
My dad had such a good old 300 TD, very reliable.
The numbers i gave are for WW2 plane engines, yet did not hear that they used odd numbers for inlines.
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Sorry for my lack of knowledge but was Erik a WW2 pilot?
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Something Google found: http://www.danford.net/erikrip.htm
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Originally posted by Xjazz
BTW
Audi had (have?) inline 5 car engine which runs very smoothly.
Inline 5 cylinder engines are common engines. Volvo has one in many cars, Audi too.
Regarding the 180° V called Boxer. I thought the term "Boxer" for those engines is wrong cause in a "real" Boxer engine the cylinders are aranged in opposite direction (and working in opposite direction) while in a 180° V-engine the opposite cylinders aren't working in opposite direction.
(Wow bad english hope u can understand this) :)
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I know the engine type you're talking about but I cant remember it's english term (4 pistons "head to head" in two cylinders with two crankshafts in opposite sides of the cyl-block).
Anyway if Porsche (http://www.porsche.com/english/dialog/faq/technology.htm) is using word Boxer when talking about their engines I'm going to do the same when talking about flat engines :)
edit:Good link (http://www.e31.net/engines_e.html)
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Originally posted by Staga
Anyway if Porsche (http://www.porsche.com/english/dialog/faq/technology.htm) is using word Boxer when talking about their engines I'm going to do the same when talking about flat engines :)
edit:Good link (http://www.e31.net/engines_e.html)
:D
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AFAIK, radials use odd numbers of cylinders per circle as to under no circumstance have TWO cylinders pushing/pulling on the central rod in opposing directions (There is no 180 degree angle 'tween two cylinders, vector addition does the rest for u)
That is actually quite a good guess as to why they use an odd number of cylinders, but the truth is a little more subtle than that.
The reason a radial has an odd number of cylinders to make the firing sequence come out smooth. These engines are all 4-stroke engines and so only fire once every *other* time that the piston reaches the top of the cylinder. With an odd number of cylinders you never have two adjacent pistons firing on the same engine revolutions.
By way of example, if you have three cylinders, the following happens during two revolutions of the engine:
- Cyl 1 fires
- Cyl 2 exhausts
- Cyl 3 fires
- Cyl 1 exhausts
- Cyl 2 fires
- Cyl 3 exhausts
At this point we can start again with the next two revolutions.
Now let's try the same thing with a four cylinder radial:
- Cyl 1 fires
- Cyl 2 exhausts
- Cyl 3 fires
- Cyl 4 exhausts
- Cyl 1 exhausts
- Cyl 2 fires
- Cyl 3 exhausts
- Cyl 4 fires
See the two exhausts right next to each other? That is why radials have an odd number of cylinders.
(BTW: BMW motorcycles and Subaru autos have 180 degree opposed boxer engines. Both are know for their reliability.)
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Originally posted by Wilbus
Sorry for my lack of knowledge but was Erik a WW2 pilot?
He sure was. Erik began flying with the USAAC in the late 1930s. During an assignment to Langley Field, he tested such aircraft as the Curtiss YP-37 and the Bell YFM-1 Airacuda. He was qualified in virtually every fighter the USAAC had prior to WWII. When Chennault was granted permission to recruit American pilots for the AVG, Erik was quick to sign up for the adventure and the promise of high pay and bounties. Chennault would come to hold Erik as one of his favorite pilots, stating, "Shilling can fly anything better than anyone." Indeed, Chennault picked Erik to defend AVG honor in a mock combat between the RAF detachment at Rangoon and the AVG. Over the course of several engagements, Shilling easily defeated his British counterpart by "flying circles around the Brewster" Buffalo with his Curtiss Tomahawk. Shilling was chosen as the AVG's recon pilot. He stripped a Tomahawk of its guns and non-essential components. He then cut a hole in the bottom of the aft fuselage, where he installed an aerial camera. Mechanics worked to tune the already hand-built Allison to peak performance. Shilling would routinely fly deep into Japanese air space and photograph airfields and military installations. His lightweight, high powered Tomahawk was capable of speeds close to 390 mph, and Erik used this to race away from pursuing Japanese fighters. After the AVG was disbanded (7/4/42), Erik signed up with CNAC, and flew transport aircraft "over the Hump" for the remainder of the war.
(http://home.att.net/~C.C.Jordan/Erikluce.JPG)
Erik later flew for various organizations, being the last aircraft in and out of Dien Bien Phu. No other contract pilot was willing to fly into that dirt strip under heavy fire. He landed a C-119 under fire, bringing in medical supplies, food and ammunition. Likewise he took off under fire taking out the sick and wounded. His C-119 taking over 50 hits, and having to fly most of the way back on one engine, Erik would be decorated by the French government for his courage.
Later in his remarkable career, Erik was a contract pilot for Air America, flying covert missions deep into Laos and Cambodia. He is rumored to have actually landed in North Vietnam, bringing in CIA operatives.
Erik was the personafication of the Flying Tiger, right until his death, which he met with great dignity and an indomidable spirit, passing on with the great satisfaction of knowing that he had made a difference. I can't think of a single person I admire more.
To read more about Erik, click on the link.
Erik Shilling (http://home.att.net/~C.C.Jordan/Shilling.html)
My regards,
Widewing
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Thank you :)
Sounds like a Great man for sure, wish I could have known him.
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porsche invented the 4 cyl boxer in one night
for the world greatest car ever seen the beetle :)
Aircooled boxers are great an very reliable also have alot off bottom power.
inline engine mostly have more power in high rev.
I believe this bottom power on radials gives the torque effect.
How reliable now i talk from experience i took my beetle on vacation a few years ago i went from holland to venice and went via Monaco, St. tropez to lloret de mar near barcelona (spain) and back to holland. I did it all with my old 44 hp boxer wich i had to start up with after- shave through my carburator. Probably my cylinder head leaked a bit. I went full gas all the road i notice some power loss in the end against hills. But it went on and on :)
And brought me through a 5000 km trip with no problems at all.
I have seen a lot off modern watercooled cars having probs standing a side on the highway.
It was a hot summer and the traffic help had 20% more cals from cars that went broke.
could never made with it water cooling.
The beetle rocks IMHO :D
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You guys did a great job on most of Wilbuz's question. But I did not see anyone address battle damage.
Inline engines like in the P51 had to have a liquid radiator cooler just like in a car. (That thing under the hood right behind the bumper)
There is no way to armour a copper radiator.
A single 30 caliber slug to the radiator ruins a pony's day.
Radial engines are more durable in battle, Coming back with 2 or more cylinder heads shot off. No liquids to lose except hydraulics & oil. Plus it would take more firepower to damage a radial.
Instead of a copper radiator, your looking at damageing a cast iron cylinder head big as your head.
That's part of why the P47's, F4u's, & F6f's have such a good reputation for ground attack. All have big radial engines, lots of power and tough as nails.
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Thanks Ghosth :)
The reason the 190 A/F/G Used radial (one of the reasons) aswell, wish that would be more modelled for all planes in AH, read stories, specially about P47's that had their engines running without any oil (didn't sound too good acording to the pilot reports) but they "worked" :)
Think I like radials better, love the sound, only need to hear a Boeing Stearman to fall in love with it.
Then again, P51 has got a lovely sound, so does spitfire, this is tough :(
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An aircooled engine makes more noise also
it's not damped by a water layer.
:)
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The more noise there is the more happy will I be :D
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The Best of the Breed
Airpower, July, 1976 Vol. 6 No. 4
by Col. "Kit" Carson
(FW.190)[/i]
The BMW 801D was a 14 cylinder, twin row radial with direct fuel injection. A 10.9 foot diameter, 3-bladed VDM prop was used and was provided with hand lever or automatic pitch control. The 801D radial air cooled engine first appeared on the Dornier 217 and the Fw-190. Its most novel feature was the oil cooler system which was a number of finned tubes shaped into a ring of tubes a little larger in diameter than the cooling fan. This ring was fitted into the rounded front portion of the cowling just aft of the fan.
I don't think this was a good idea. For example, my principal aiming point was always the forward portion of an enemy ship; the engine, cockpit, wing root section. If you get any hits at all, even only a few, you're bound to put one or two slugs into the engine compartment. Having a couple of bullets riccochet off the engine block and tear up some ignition harness is not too bad at all, at least not fatal. But to have all those thin-walled oil cooling tubes ahead of the engine is bad news. Any hits or riccochets in the engine section are bound to puncture the oil tubes. Then the whole engine is immersed in oil spray, and sometimes it would flash over into a fire. All of the 12 Focke-Wulfs that I shot down sent off a trail of dense, boiling oil smoke heavy enough to fog up my gun camera lens and windshield if I were so close.
The Best of the Breed
Airpower, July, 1976 Vol. 6 No. 4
by Col. "Kit" Carson
(Me-109)[/i]
In principle the DB601 and 605 series engines were the same as the Allison or Merlin, except they were inverted and had direct fuel injection; otherwise they were 12-cylinder, 60 degree Vee, glycol cooled engines. The prop was a 10.2 foot, 3 blade variable pitch mechanism of VDM design. here is another major difference between their design approach and ours. The pitch on the Me-109 prop could be set at any value between 22.5 and 90 degrees, a visual pitch indicator being provided for the pilot. There was no provision for automatically governing the rpm. We did just the opposite, using a constant speed governor and flying by a constant tachometer indication of rpm. For any flight condition the rpm remained constant. We didn't know, or care, what the blade angle was.
Much has been written about the which was better, the US Navy used radial engines almost exclusively due to thier reliability, that and if the engine took a few hits the it continued to run, whereas an "inline" typically would sieze up if the coolant (i.e radiator, engine block) took any damage.
For this reason pilots felt secure using the P-38 for ground support, as they had TWO engines, kinda like having one in reserve to get home on.
And of course the P-47 reknown for it's JABO work was a radial engined A/C, practically immune to small arms fire from the ground.
The P-51 although it too did much ground support work had it's radiator mounted low, and was therefore quite vunerable to ground fire.