Vfrpilot : The aircraft must have already been run or had heaters in it. I could not imagine any pilot starting a cold soaked aircraft and taking off in 3 or 4 minutes.
In Canada there are various pre-heating devices available. Tanis Corporation has heating pads that are attached to the gear boxes, oil reservoirs, and fuel control units.
Most operators of light helicopters in Canada use car interior heaters and insulated engine covers. On a Jet-Ranger
one would go in the transmission area, another in the engine compartement, and a 3rd in the cabin. In addition to car heaters operators also employ heated battery blankets. Of course in the absence of a battery blanket one could remove the battery and keep it inside ( a warm building).
Because of unusaual circunstances I have even seen a 60 watt trouble light placed under the fuel control of a 206 a -40.
Temperatures of -27 would probably require a 10 minute warm up to get all the oil temperatures up into the proper operating range. In addition If I were operating at that temperature and had to wait for a client I would start and run-up the aircraft ever hour or so,.