Junkers Ju 88A-1, Jumo 211 Props rotation ?

[redleader]

What was the direction of rotation of the props on the A-1 Schnellbomber?

[Lawzer]

Counter clock wise by the look of things: 

http://www.asisbiz.com/il2/Ju-88/(F)121/pages/Junkers-Ju-88A-1.(F)121-undergoing-a-tyre-change-Sicily-1942.html

[stevehnz]

Counter clock wise from standing in front, clockwise from the pilots viewpoint.

Steve. 

[RAS]

Just a thought - one clockwise the other anti clockwise then the torque is evened out.

 

[stevehnz]

Although a good idea in theory, it didn't seem to catch on for anything other than small high powered twins such as P-38s & DH Hornets. Possibly some others I'm not aware of too.

Steve

[JWM]

12 hours ago, Lawzer said:

Counter clock wise by the look of things: 

http://www.asisbiz.com/il2/Ju-88/(F)121/pages/Junkers-Ju-88A-1.(F)121-undergoing-a-tyre-change-Sicily-1942.html

Be careful - the photo is described Ju 88 A1 but is is later variant - look at the wingtips!

Here is A1 (so OK, both goes counter clock wise if you look from front):

The two directions of rotations were typical for French bimotors with GR engines. BTW - the torque in bimotor is not a big problem since there are two different axes of rotation and it does not sum that easy in algebra as they oblige rules for  pseudo vectors. 

Regards

J-W

 

 

[redleader]

Cheers lads. Yeah I wondered whether both rotated the same way or in opposite directions

[JWM]

3 hours ago, redleader said:

Cheers lads. Yeah I wondered whether both rotated the same way or in opposite directions

Here is another early from web site

https://www.worldwarphotos.info/gallery/germany/aircrafts-2/junkers_ju88/ju-88-a-1-a-0-of-ii-kg-30/

Described as A1 or A0. Both the same  direction

Cheers

J-W

 

[Graham Boak]

Generally speaking they both rotated the same way because that meant you didn't need so many spare engines, and the  asymmetric effect wasn't significant at that period with large aircraft.

 

Incidentally, the Merlin was the odd one out, the vast majority of engines rotated.clockwise - it was judged as seen from the cockpit.  I haven't seen any reason given why, but it did lead the RAE to issue an instruction that no newer engine did it that way.

[JWM]

The direction of rotation had something to do in times when you start engine with a help of a person, who started rotate it. Since majority of people are right handed this was chosing one direction (i think clock wise looking from front). What do you think?

Cheers

J-W

 

[Work In Progress]

2 hours ago, Graham Boak said:

Generally speaking they both rotated the same way because that meant you didn't need so many spare engines, and the  asymmetric effect wasn't significant at that period with large aircraft.

 

Incidentally, the Merlin was the odd one out, the vast majority of engines rotated.clockwise - it was judged as seen from the cockpit.  I haven't seen any reason given why, but it did lead the RAE to issue an instruction that no newer engine did it that way.

The only benefit of the Merlin's odd prop rotation by British / French / Russian standards was proabbly from the point of view of the USAAF, in that it conformed to the US standard, as American props generally go the 'wrong' way round. The last mass-produced piston aero engine with 'correct' prop rotation of which I'm aware is the delightful Russian Vedeneyev M-14P geared radial and its siblings, which I think is still in limited production.

Edited April 9, 2018 by Work In Progress

[noelh]

    VB

On 4/8/2018 at 6:12 AM, RAS said:

Just a thought - one clockwise the other anti clockwise then the torque is evened out.

 

A good idea but not often applied. The P38 was like that and Hornet later had opposite turning propellers. But for example the Mossie could be tricky if an engine failed during take off before the minimum control speed on either engine, but particularly if the left engine failed. On other twins the right engine was the 'critical' engine. That lasted right into the post war light twins with propellers turning the same way. Some light twins had a horrendous reputation.  However the only one I ever flew had counterrotating propellers. So that was one less worry.