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Aquila,
First thank you for reviewing our Accu-simmed P47, and for the compliments on the manuals. We spend a lot of time trying to make things simple as we assume the user knows nothing. Also, yes, thinking about this, we should have explained this area of engine damage in a bit more detail. Here is a review:
Detonation
If your mechanic inspects the engine and sees signs of detonation, it is usually a result of too much power and / or high carb air temps. Keeping the power within limits, cool carb air temps, and using water injection all help to insure a properly running engine. You will hear detonation before it becomes damaging, so listen to your motor.
Stress
Stress damage can happen by simply over-torquing your motor. A common cause is running very high power at lower RPM which is something all pilots know is a big no-no. You will hear your motor being pushed too hard here too, so along with proper techniques, listening to your motor is key.
Heat
Running very high CHT (Cylinder Head Temperature) can cause parts to fatigue, change shape, oil to break down, and damage to result. This is usually caused by pushing an engine too hard without adequate air flow to remove the heat. Also, even idling on very hot summer days where the tarmac is hot can create hot conditions. Probably the most common reason for overheating an engine is the pilot not backing off power soon enough after takeoff. Some just keep the throttle at full and enter into a steep climb, which is terrible for the engine to do right after a full power takeoff. As soon as you are airborne, keep your nose down. Retract flaps and reduce power. The engine will be at its hottest at this initial climb point, so I tend to go a bit easy at first. Once you start getting up into cooler air while keeping speed up, you can add a bit more power. Also, water injection helps considerably to keep the CHT lower.
Wear
This is just general wear of running an engine. Those who use better habits like keeping the engine as cool as possible, not pushing it too hard, etc. will get a longer lifespan out of the engine.
Shock Cooling
Also, some have asked us about shock cooling. This is modeled in Accu-sim, but I think the word “Shock Cooling” to non pilots can sound like something is going to blow in your engine. If you have a hot engine and are running in cool air, and suddenly pull back the power and go into a dive, what happens is the very hot engine is rapidly cooled. It’s like pouring cold coolant in a piping hot engine. That cold water hits the block, and it can crack it. However, in an air cooled engine, Shock Cooling is not something that will typically destroy your engine. It is simply a matter of learning good habits, and not to ‘shock cool’ your engine as it does add wear, weaken the metal, and can cause a malfunction. Sometimes you will have an engine that is used in flight training that is constantly being shock cooled by untrained pilots. The result is this engine will get overhauls sooner, is more likely to fail, etc. This is how Accu-Sim works. It literally monitors the temp, and if the temp rapidly changes, it weakens the metal. The engine will degrade quicker over time and the chance of a sudden failure is higher.
The end result is you get the rewards over the long run of using proper flying techniques.
Blown oil pump
When you start a cold engine, the oil can be thick which causes very high oil pressure. Running the engine over 1,000rpm under these conditions can cause critical pressures that can damage the oil system. If your oil pressure suddenly goes to 0, there is a problem.
Blown Hydraulic Pump
This is unlikely, but can happen for no other reason than you just had a pump that failed. You may lose pressure over time and will need to use your hand pump.
Broken or frozen flaps
Accu-Sim measures the force being put on the flaps. You can pop your flaps out a bit even at very high speeds without risk of damage (using it as a maneuver flap), just like any aircraft. Just be careful not to deploy it too much as pressure increases drastically as the flap angle increases. If this force gets too big, you could break the hardware or possibly jam / bend it. Breaking something would cause the flap to just be loose without any control. In flight, it may wobble based on forces, but once you stop on the ground, it will just hang. Jamming your flap will cause it to not move.
Jammed Gear
The landing gear is strongest when it is locked and down, and weakest when it is moving. If you are moving too fast and your gear is down, pull back and reduce speed. Don’t retract it because in this state it is more likely to break. Don’t operate your gear over 200mph. You can push it, the gear is tough. You may even get 300mph with gear down before it is damaged to the point of jamming.
Also, listen to the airframe too. You will hear the rumble of flaps and gear and quickly get used to what is or isn’t acceptable. You can even get buffeting under very high stress from drag.
I hope this helps.
Scott.
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A2A Simulations Inc.
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