Icing in R/W Aircraft

[sycamore]

M-H Driver, if you can look back at `rotorheads around the World,views from the cockpit(not video),page 15 /16,you will see some photos of icing on the rotor/etc on the Wessex/Wasp/Gazelle/Sea-king trials I was involved in between 1969-75.Admittedly old technology aircraft/aerofoil sections,and different engines to todays helos; however ,we did it as test flying with specific limits and modifications to the aircraft,wore parachutes,had lots of instrumentation,and generally operated in an area where the weather was benign,and with a safe cloudbase ie generally stratiform cloud, hopefully with uniform cloud density,and water content/droplet size(or,hopefully so,not always true.)As a general limit,we used 15-20 % TQ rise as a guide if the blades were `shedding ice(no blade heating) as a limit to descend /get out.now if it didn`t shed/or Tq rose(fixed collective).We had also decreased the Minimum blade pitch at Min.pitch on ground,as the engines were susceptible to ingestion and could surge(Gnome/T58)readily,to cover,hopefully,the rapid drag/blade stall if both engines failed.And you can see on one of the photos the shape of the ice build-up that occurs.`Idle-stop ` and others will hopefully endorse it if I say that you cannot/should not consider flight into known icing unless you have a fully prepared /cleared aircraft; and if you inadvertently get into it in a non-certified a/c,get out as soon as you can.
A last point for those with certified a/c...Do you have a `stabiliser` de-icing system..?as the autopilot may have difficulty holding attitude.IAS if the `stab starts to pick-up ice.....
Safe flying all....Syc..

ps.I would also endorse SAS`s freezing rain..any rain around +-2 can give you a slow TQ rise,and little or no shedding,even with heated blades,maybe because of heated blades,as it will form behind the heating elements and re-freeze.....Sometimes you have to give the head a real shake/stir to get it to break.If you lose an engine,or two,crank it into a steep bank to get the RRPM back...RRPM is life...don`t lose it. See also the discussion on entering autos...