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another radial question



 
 
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  #1  
Old September 23rd 07, 12:57 AM posted to rec.aviation.piloting
Tater
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Posts: 35
Default another radial question

after looking at all the planes in the oshkosh museum, I saw a few
radials where the crank was stationary, and the rest of the engine
moved with the prop.

which brought me to this question. why did they use radials? some of
the first planes used inline engines, nut for some reason radials came
into play.

  #2  
Old September 23rd 07, 01:02 AM posted to rec.aviation.piloting
Capt. Geoffrey Thorpe
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Posts: 790
Default another radial question

"Tater" wrote in message
oups.com...
after looking at all the planes in the oshkosh museum, I saw a few
radials where the crank was stationary, and the rest of the engine
moved with the prop.

which brought me to this question. why did they use radials? some of
the first planes used inline engines, nut for some reason radials came
into play.


Good cooling with all the cylinders whirling in the breeze.

BTW: They are called "rotary" engines - "radials" have stationary cylinders
(but are also easier to cool)

--
Geoff
The Sea Hawk at Wow Way d0t Com
remove spaces and make the obvious substitutions to reply by mail
When immigration is outlawed, only outlaws will immigrate.


  #3  
Old September 23rd 07, 01:05 AM posted to rec.aviation.piloting
[email protected]
external usenet poster
 
Posts: 1,130
Default another radial question

On Sep 22, 6:02 pm, "Capt. Geoffrey Thorpe" The Sea Hawk at wow way
d0t com wrote:
"Tater" wrote in message

oups.com...

after looking at all the planes in the oshkosh museum, I saw a few
radials where the crank was stationary, and the rest of the engine
moved with the prop.


which brought me to this question. why did they use radials? some of
the first planes used inline engines, nut for some reason radials came
into play.


Good cooling with all the cylinders whirling in the breeze.

BTW: They are called "rotary" engines - "radials" have stationary cylinders
(but are also easier to cool)

--
Geoff
The Sea Hawk at Wow Way d0t Com
remove spaces and make the obvious substitutions to reply by mail
When immigration is outlawed, only outlaws will immigrate.


Radials have a short, stiff crank, which keeps the weight
down. All the cylinders (in a single-row radial) get lots of cooling
air. On old airplanes the whole engine was out in the breeze. No cowl,
no baffles, no nothing. Light and cheap.

Dan

  #4  
Old September 23rd 07, 03:33 AM posted to rec.aviation.piloting
Morgans[_2_]
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Posts: 3,924
Default another radial question


"Tater" wrote

which brought me to this question. why did they use radials? some of
the first planes used inline engines, nut for some reason radials came
into play.


Reasons for widespread use of radials

#10 Simplicity
#9 Durability
#8 Reliability
#7 Ease of repair
#6 Able to take battle damage without quitting
#5 Ease of repair after #6 occurs
#4 Weight
#3 Weight
#2 Weight
#1 Savings of all the above Weight
--
Jim in NC


  #5  
Old September 23rd 07, 08:19 AM posted to rec.aviation.piloting
James Sleeman
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Posts: 106
Default another radial question

On Sep 23, 11:57 am, Tater wrote:
after looking at all the planes in the oshkosh museum, I saw a few
radials where the crank was stationary, and the rest of the engine
moved with the prop.


An engine with all the clyinders spinning around a stationary crank
(and the prop bolted onto the engine) is called a Rotary engine.
World-war-one vintage stuff.

The main reasons for thier usage in those early times was that the
engines of the time were big, inefficient, and rotated slowly, this
meant a couple of things, first is that they needed good cooling (esp
when the aircraft was on the ground) and second is that a plain radial
of the time (rotating crank) would introduce lots of nasty power-pulse
vibration due to the slow running and large combustion strokes. With
a rotary, the engine itself becomes an *enormous* flywheel which both
provides cooling for the cylinders even if the aircraft is stationary,
and also smooths out the power.

The big disadvantage is you effectively have built a massive gyroscope
onto the front of your plane, which radically affects the handling, if
you move with the gyro then the effect can be used to your advantage
(if it doesn't take you by surprise first!), but that big engine only
spins in one direction so moving against the gyro causes some issues.
And of course when you open the throttle and the engine starts
spinning faster, your whole plane is going to have a very distinct
notion to roll over with the engine.

As engine technology improved (fairly rapidly), the advantage of a
rotary (spinning engine) over a radial (spinning crank) waned and
radials took over.

Radials are not common in modern aircraft having been surplanted by
inline engines, however they do still find favour in certain
applications (bush flying for example) due to thier relative
simplicity and therefore reliability (if treated right).

  #6  
Old September 26th 07, 01:30 AM posted to rec.aviation.piloting
Tater
external usenet poster
 
Posts: 35
Default another radial question

On Sep 22, 6:57 pm, Tater wrote:
after looking at all the planes in the oshkosh museum, I saw a few
radials where the crank was stationary, and the rest of the engine
moved with the prop.

which brought me to this question. why did they use radials? some of
the first planes used inline engines, nut for some reason radials came
into play.


hey, thanks for all the replies, but it brings up one more
question.....

why don't we use radials now?

  #7  
Old September 26th 07, 01:47 AM posted to rec.aviation.piloting
[email protected]
external usenet poster
 
Posts: 58
Default another radial question

On 26 Sep, 01:30, Tater wrote:
On Sep 22, 6:57 pm, Tater wrote:

after looking at all the planes in the oshkosh museum, I saw a few
radials where the crank was stationary, and the rest of the engine
moved with the prop.


which brought me to this question. why did they use radials? some of
the first planes used inline engines, nut for some reason radials came
into play.


hey, thanks for all the replies, but it brings up one more
question.....

why don't we use radials now?


For lower power engines the air cooled flat 4/6 has
turned out to be the winner. higher power
requirements are best met with a gas turbine.

I think that the smallest turbines in widespread use
are about 400hp.

Smaller ones do exist:-

http://www.youtube.com/watch?v=OVxeZYdVRLM

http://www.jet-man.com/actuel_eng.html

  #8  
Old September 26th 07, 02:00 AM posted to rec.aviation.piloting
Mike Granby
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Posts: 83
Default another radial question


why don't we use radials now?


Lubrication is a messy business, AIUI.

  #9  
Old September 26th 07, 08:39 AM posted to rec.aviation.piloting
Bertie the Bunyip[_19_]
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Posts: 3,851
Default another radial question

Tater wrote in news:1190766611.292026.287600
@g4g2000hsf.googlegroups.com:

On Sep 22, 6:57 pm, Tater wrote:
after looking at all the planes in the oshkosh museum, I saw a few
radials where the crank was stationary, and the rest of the engine
moved with the prop.

which brought me to this question. why did they use radials? some of
the first planes used inline engines, nut for some reason radials came
into play.


hey, thanks for all the replies, but it brings up one more
question.....

why don't we use radials now?


I do, why don';t you?

Bertie
  #10  
Old September 26th 07, 03:37 PM posted to rec.aviation.piloting
Paul kgyy
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Posts: 283
Default another radial question


why don't we use radials now?


The large frontal area produces more drag (lower airspeed), and note
the statements above about reliability "if treated right". They also
limit forward visibility to some extent.

Having said that, they are still used a lot. I've heard that one nice
thing about radials is instant power response.

 




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