Why is the DH Dove tail asymmetrical?

Going off at a slight tangent……

The wartime Macchi C.200 Saetta and C.202 Folgore had asymmetrical wings – with the port wing being 21cm longer than the starboard – to counteract engine torque.

Ken

Those examples were built in 1949 and 1947 respectively and so were early examples delivered prior to the adoption of the asymmetric elevators.

Can’t find an asymmetrical tail here
http://www.dehavilland.co.za/images/DH104%20Dove%2004235%20SAAF%20101%20John%20Miller.jpg
and here
http://www.edcoatescollection.com/ac5/ROW%20Asia/VT-CQA.jpg

Martin

Like all de Havilland’s, it is a pleasant aircraft to look at, even if it is the ugly duckling from this designer.

The cockpit bump does look excessive, but I am sure pilots appreciated it!

Here you go Christer:

Thanks, that starboard side certainly looks different than the “rounded” in the drawing I linked to!

One elevator gets a fence effect from the slab side of the fuselage and the other side doesnt .

It is definitely to do with airflow from the Props, Hence the Riley Dove has swapped the side of the asymmetrical elevator

Yes and also on some Warwicks. I have found another comment (in the “Vickers Aircraft since 1908” this time) which also mentions asymmetric turblence from propwash from high-power piston engines reaching the tail surfaces, so it does seem to be a question of reducing snatching on the elevators rather than anything to do with single-engine performance. Do you have a reference for the claim that the starboard elevator was increased at the same time?

And, I believe it had previously been found on the Viking.

Actually, that article is wrong. In the event of single engine failure, the asymmetric airflow over the fuselage caused one elevator to become less effective than the other. In order to rectify this, the port elevator tip was cropped and the corresponding starboard elevator horn increased. This occurred right from the early production and had nothing to do with the later engine changes.

Here you go Christer:

http://www.airliners.net/photo/Jordan-Air-Force/De-Havilland-DH-104-Dove-7/806438

See the penultimate paragraph in this link:

https://www.flightglobal.com/FlightP…20-%202057.PDF

That ties it down pretty well thanks.

Could someone post a picture or a link to a picture of this arrangement? I have gone google on the tail of the Devon and found drawings/pictures with either square tipped or rounded tailplane but not one of each.

See the penultimate paragraph in this link:

https://www.flightglobal.com/FlightPDFArchive/1970/1970%20-%202057.PDF

While this was discussed in a previous thread, I can’t find it now. So, ‘De Havilland Aircraft since 1909’ only refers to the production change to the tailplane being in order to reduce buffetting (a form of turbulence, a different effect to asymmetric forces). This suggests that propellor swirl tended to cause a problem on that side resulting from interaction with downstream parts of the airframe. Does anyone have any more specific information?

I always thought it was the vertical component of the tailplane, along with rudder and trim tab, that sorted out the assymetrical swing of the airflow coming off the props on a multi-engine aircraft. The Dove though has different size/shaped horizontal tail surfaces. Surely the rotational vortices off the props would have an upwards push on one side, countered evenly by downward push on the other? So is the answer really as easy as the above replies suggest, just why different shape and length of the horizontal tail surfaces?

Blohm und Voss 141.

Few, however, are quite as asymmetric as the Rutan Boomerang.

As per the VIKING!

Probably because the props both go the same way round, so some aerodynamic balancing is required. Many propeller-driven aircraft are asymmetric to some greater or lesser degree.