1,567
edits
Difference between revisions of "Common Questions and Answers"
Jump to navigation
Jump to search
→Other Questions: Add What is the process before takeoff? Section
(→Other Questions: Add What does "sloshed/suitable for aromatic fuel(s)" mean? Section) |
(→Other Questions: Add What is the process before takeoff? Section) |
||
| Line 314: | Line 314: | ||
The aircraft that had this treatment therefore had a note added to the technical data block on the side of the fuselage that it was safe to use these type of fuels in them. | The aircraft that had this treatment therefore had a note added to the technical data block on the side of the fuselage that it was safe to use these type of fuels in them. | ||
=== What is the process before takeoff? === | |||
# Pulling propeller through | |||
#:* Before they even enter the airplane, the pilots will pull and push the propellers through a certain number of complete rotations to ensure that the engines are not hydraulically locked. If this were the case, when attempting to turn them they would reach a point that they could not move any further. | |||
# Pre-start checklist | |||
#:* There are a variety of settings and instruments to check to ensure they are properly configured before starting the engine. This is performed via "call and response" between the pilot and copilot in the cockpit, so the only evidence of this from the ground will be a delay where it appears nothing is happening. | |||
# Ground power (optional) | |||
#:* Although most World War II aircraft have a battery to power their electrical starter, they can also be started using a "battery cart" that plugs into the side of the aircraft. This lessens wear on the battery. Once the engines are started, the cart is unplugged by a member of the ground crew. | |||
# Bumping the propellers through | |||
#:* The pilots will then slowly rotate the propellers with the engine starter to check again that the engine is not hydraulically locked. As they do so, they will "count blades" to make sure that every cylinder has gone through compression. | |||
# Call "Clear!" | |||
#:* This callout alerts anyone on the ground that the engines are about to start and they should clear the area.{{efn|Sometimes expanded to “Clear Prop!” The callout “Contact!” serves the same purpose, but for hand propping.}} | |||
# Engine start | |||
#:* The engines will initially exhaust a large amount of smoke before clearing up. This is the result of the extra oil in the cylinders being burned off. The amount and duration of smoke will therefore generally depend on how long the airplane has sat since its last flight. | |||
# Oil temperature wait | |||
#:* Much of the time spent on the ramp before the airplane starts rolling is waiting for the engine oil to warm up. When cold, oil is more viscous and attempting to push thick oil through an engine can result in a failure of some component. | |||
# Control surface checks | |||
#:* The control surfaces are moved to their fullest extent of travel in each direction to ensure that they are not blocked. | |||
# Magneto checks | |||
#:* Piston aircraft engines have two magnetos and for redundancy each controls one of the two spark plugs per cylinder. The pilots will briefly switch off both magnetos to confirm that they are working properly. This step, called idle ignition grounding, ensures that the engine can be shut down if necessary and results in it briefly sounding like it is cutting out. | |||
# Taxi out | |||
#:* The aircraft leaves the ramp and taxies to the end of the taxiway. | |||
# Run up | |||
#:* Once the aircraft reaches the end of the taxiway, the throttles are briefly advanced to near takeoff power before being brought back down again. This serves the same purpose as the control surface check, but for the engines. | |||
# Takeoff | |||
This guide is written for the benefit of a person watching the airplane from the ground. As a result, it omits or simplifies certain steps in the process that are not evident from this position. Furthermore, it is written in reference to a B-25, but while there are minor differences from airplane to airplane (e.g. number of pilots and engines), the steps are generally similar.{{efn|For an in-cockpit example, see: {{cite web |title=(4K POV) B-25 Mitchell | Formation Flying & Low Passes | Tri-State Warbird Museum |url=http://www.youtube.com/watch?v=gP-6tXyT5B8 |website=YouTube |date=2024}}}} Third, while certain steps must occur in a specific order, a few can be performed at different points between the aircraft leaving the hangar and takeoff. | |||
== References == | == References == | ||