Russian aircraft - what is that on the fin?

[witchdoctor]

Always wondered, but never thought to ask. What is that pod that most of the older generation of Soviet-era jet transports (Tu 134/154 and Il 62/76 for example) have on top of the fin? I just can't think what it is as there doesn't seem to be an obvious equivalent anywhere on other manufacturer's aircraft.:confused:

[Boss Raptor]

Just an aerodynamic fairing as on a VC10, not aware of any equipment inside it

[noisy]

Acorn fairings are sometimes used in order to stop the control surfaces resonating/fluttering at high Mach numbers. They can be seen on such classic British types as the Hunter & Victor.

:ok:

[HotDog]

Noisy is right, they are flutter dampers, very heavy, usually made out of depleted uranium. Also used on older western aircraft.

[noisy]

Hotdog-is that true about the depleted uranium? I didn't know that. I thought that the effect was purely aerodynamic.
I knew that DU was used *in* certain control surfaces.

[Boss Raptor]

There is no DU on the TU134, 154 and IL62, in this case it is purely a forward pointing aerodynamic fairing. On the TU's the fairing is fixed to the tailplane, the IL62 fairing moves with the angle of the all moving tailplane which alters angle dependant on flap setting, low airspeed etc.

[747FOCAL]

It is my understanding that a lot of older commercial aircraft used depleted uranium as tail weight.

[noisy]

747focal

i understand after reading the report on that korean 747 that went into the field outside stanstead that there is DU in the rudder and the elevators.

noisy

[CR2]

Found this here (http://www.transonicaviation.com/faq.html)
.... the component that poses the greatest risk are the Flight Control Counter-Balance Weights. The weights are made of depleted Uranium 238, which are 100% Cadmium Plated, emits low levels of radiation that is not harmful to humans, but these weights must be handled with caution. The true danger arises if a person were to grind through the cadmium plating. This action would cause radioactive Alpha particles to become airborne. Ingestion of these particles may cause irreparable damage to one's internal tissues. Maintenance professionals should remember that, if grinding is a required action, use gloves, industrial eye protection and a respirator. Gloves, wrapping material, wiping cloths, respirator filters, or any other articles used in the handling of damaged balance weights should be discarded and appropriately labeled as radioactive waste and disposed of accordingly. For more information see Advisory Circular 20-123 - AVOIDING OR MINIMIZING ENCOUNTERS WITH AIRCRAFT EQUIPPED WITH DEPLETED URANIUM BALANCE WEIGHTS DURING ACCIDENT INVESTIGATIONS.

[Aboveglidepath]

Don't quote me on this, but the phrase 'mach cone' springs to mind. Not sure if it has anything to do with area-ruling, but I think that's what its called.

[phnuff]

Didnt the issue of DU first hit the headlines following the EL AL 747 freighter crash on the Amsterdam suburb when a few years later, luekemia rates in the area showed a sudden upturn ?

[swish266]

DU my a--!

On all Russian jet airliners with T-tail this fairing houses the actuator ( on bigger - hydraulic, on smaller - electric) for positioning the stabiliser...

Stop the bulls--t. That's it.

[Boss Raptor]

The forward pointy thing on the tail of a TU134/TU154 does not contain DU (why should it as it doesnt move and is not a control surface), it does not contain the jackscrew which is within the vertical tailplane itself at the top, it does not move, it is an aerodynamic device which has effect on the airflow over the tailplane

A Russian GSGA Inspector has just told/confirmed to me on the phone ;)