Radials

[Dave T]

A couple of radial engined aircraft shots.

[yancovitch]

two great designs....always wondered if the radials used counter rotation props.....or is that counter active?

[papituwall]

Contra rotation propellers are independent of the "achitecture" of the engine. At the reduction gear of the propeller is where there can be two counter-rotating propellers.

When you say "counter active" i can imagine that you are thinking in this: There is (was) a radial (architecture) variant where the engine is rotating, the Gnome-Rhône rotary engine.

https://www.youtube.com/watch?v=CYc-H8Wg-MQ

http://www.animatedengines.com/gnome.html

You can search in the net for Gnome-Rhône

[Hagar]

two great designs....always wondered if the radials used counter rotation props.....or is that counter active?

I think you mean counter rotation as used on some twins where the prop on the left engine rotates in the opposite direction to the one on the right. For example on the P-38 Lightning. I could be wrong but I can't think of any radial-engined types using this configuration.

Contra-rotating props are where both props are on a single shaft, one behind the other as on the Westland Whirlwind fighter.

The Gnome-Rhone was a rotary engine used mainly on wwI fighters. This was superseded by the radial engine soon after the end of the war.

[papituwall]

Some examples:

PISTON ENGINED

Macchi MC72



Supermarine Spitfire Mk.21, also Seafire 47





Avro Shackleton



TURBOPROPS

Westland Wywern



Fairey Gannet



Douglas Skyshark

[img]https://1000aircraftphotos.com/Contributions/Juvet/1583L-1.jpg
[/img]
Tupolev 95 to 142 and 114

[Hagar]

Oops! I meant Westland Wyvern in my previous reply, not Whirlwind.

Some examples:

PISTON ENGINED

Macchi MC72

Supermarine Spitfire Mk.21, also Seafire 47

Avro Shackleton

TURBOPROPS

Westland Wywern

Fairey Gannet

Douglas Skyshark

Tupolev 95 to 142 and 114

These are all examples of aircraft with contra-rotating props - NOT counter-rotating engines which is completely different.
See this vid of the P-38 Lightning with counter-rotating engines. https://www.youtube.com/watch?v=yZjzJFH-hsE

[yancovitch]

hagar is right....counter-rotating, as in the lightening....what are the advantages or disadvantages....i thought that the lightening was very a successful aircraft....why wouldn't the other twins follow suit?

[Hagar]

hagar is right....counter-rotating, as in the lightening....what are the advantages or disadvantages....i thought that the lightening was very a successful aircraft....why wouldn't the other twins follow suit?

The advantage is lack of torque & P-factor effects which makes for easier handling, especially on powerful twins. Apart from cost the main disadvantages are production & spares holdings, the engines & props both being handed & not interchangeable. This could cause serviceability difficulties with military aircraft in remote locations if stocks of either left or right engines/props became unavailable. During WWII the RAF did not want to have the logistics complications of dealing with handed engines.

I read somewhere that Rolls-Royce experienced problems developing an opposite rotation Merlin intended for the DH Mosquito which had a nasty swing on take-off. It's not just a simple case of adding an extra "cog" in the reduction gear train. However, they obviously overcame these problems for use in the later DH Hornet.
https://en.wikipedia.org/wiki/De_Havilland_Hornet

[papituwall]

Oops! I meant Westland Wyvern in my previous reply, not Whirlwind.

These are all examples of aircraft with contra-rotating props - NOT counter-rotating engines which is completely different.
See this vid of the P-38 Lightning with counter-rotating engines. https://www.youtube.com/watch?v=yZjzJFH-hsE

In fact the Macchi MC72 had two engines in tandem, so the engines were counter rotating.

[napamule]

But...only ONE 'prop' and not TWO different props (on different engines). Do I get the shaft?
Chuck B
Napamule

[papituwall]

No, the MC72 had two contrarotating propellers, two blades each. More info here:https://en.wikipedia.org/wiki/Fiat_AS.6

In this video at 0:51 you can see the start of the engines:

https://www.youtube.com/watch?v=gLRLhZJsCh4

You can see in this pictures: