I am not a real pilot nor an airplane engineer but infinite flight has made me wonder why are most planes made to be nose heavy rather than be balanced? The way I made this observation is that most planes need a positive trim for take off and landing, the newly reworked A330 for example needs 40% trim for take off and 50% trim for landing, and it only becomes balanced when the plane is flying over 300 IAS, which is only 5-10% of the total time of the flight. At cruise altitude the plane would still need at least 25% trim. I tried fully loading the rear cargo bay while leaving the front cargo bay empty to counter the imbalance, but the plane still felt nose heavy and needed over 20% trim for the majority of the flight. I might be naive but shouldnāt planes be designed to be most balanced during cruise, meaning they should need 0% trim during cruise when theyāre flying around 240-280 IAS above FL300 if the cargo and passengers are well balanced? Or is there something I am doing wrong? I usually fly with over 250 passengers (depending on model), a fully loaded rear cargo bay and a half full front cargo bay. And I carry enough fuel to reach my destination at MLW (I weirdly enjoy heavy landings).
It depends on the plane in all fairness. I do not have too much of an issue with this. Normally I dont go above 30% trim and Iām at no more than 5 during cruise. Iām not sure how they handle in real life but the newer planes will have more realistic flight models. My best bet for getting used to the nose heavy is cutting down on the trim and just trying that out and you will get used to it.
Planes are mostly nose heavy to prevent stall.
If planes were tail heavy this could lead to a stall, as you already know. However the nose is not overloaded. Its just a little heavier than the rear.
The way an aircraft is typically loaded or designed is to have the centre of pressure (the point at which the lift acts) just behind the centre of gravity (the point at which the weight is assumed to act). This creates a slight nose-down pitching moment, creating the nose-heavy effect you feel during flight.
This effect has to be counteracted by pulling up slightly on the elevators, hence where the 30% or whatever trim during cruise comes from.
This doesnāt necessarily reduce the risk of stalling, however it does explain why the nose drops during a stall in order to aid recovery.
This is a very brief, generic explanation. But I hope it helps nonetheless.
In my experience in IF, the need to.trim comes from airspeed, which seems logical.
For instance, withe the A330, I use about 40% positive trim for take off, which I the gradually decrease to 0% at 300kt while climbing, which is roughly dtandard cruise speed whilst in Mach altitudes.
When descending, I trim gradually to about 20% when reaching 250kt, then about 40% at 180kt (flaps 2), and slowly to about 65% on final at Vapp.
Values above for about 185 tons TOW and 180 LW. More weight usually requires more positive trimming.
The same principle applies in my experience (A320/319, TBM, B757, B777) for all other aircrafts, with particular values of course.
In one word, planes appear balanced at their standard speed and need positive triming when flying slower.
My two cents, happy flying.
I will try to explain this in a more technical terms and hopefully itās easily understandable. Basically just imagine u are looking at the aircraft from the sideways view and thereās the CG which is acting downwards of course and the CP( Centre of Pressure) which basically means the average location of lift force is happening at, just think of it like the CG where the weight of the aircraft acts upon on average. Adding on to what @A_Hippopotamus is explaining thereās also something called the moment arm , just imagine u are driving a car and now u want to park and u have to pull the handbrake isnt it? Imagine if the handbrake is short do you think u can easily pull it? No of course. Hence why they designed the brake lever to be longer . The distance between your hand and the end of the handbrake lever is termed as the moment arm. So if the distance of the moment arm between the aircraft elevator and the CG is further then u have a larger moment arm hence u will be able to manoeuvre the aircraft more easily( control surface more effective). So say u are in a stall and want to pull out from it obviously a larger moment arm will benefit from this. Imagine u have a short moment arm( Aft CG) u wont be able to manoeuvre the aircraft easily in a stall hence why most aircraft prefer a slightly nose heavy configuration. Also during a stall u would always want the plane to go nose down hence why it is more preferred to have the CG ahead of the CP otherwise if the nose is going to pitch up u would go into a deep stall which is not what we want because it is very hard or close to impossible to recover. Correct me if i am wrong @A_Hippopotamus
Jesus you all use so much trim, sometimes I use negative trim š . I always stay within -5 trim and +30 trim I usually use +15 for landing in the a330, and Iāve been doing a lot of long haul with it leaving me very light at the end of the flight so I use flaps 3 landing which makes the plane nice and floaty but it can land like a champ if you know how to fly it
I only occasionally use trim in IF (but I calibrate a lot). I learned to fly before first using a simulator.
If you didnāt trim when in an actual aircraft, your brain and muscles would be constantly fighting the changing vertical aerodynamic forces on the elevator as you change phases of flight (change speed, flaps, gear etc.)
In an actual aircraft you trim for each flight configuration to, in a sense, relieve the muscle/brain work (my FAA examiner called it āweight liftingā). No human can fly an aircraft without trim for very long. Concentration has itās limits.
When pitching a phone as the control device, unfortunately there is no way to feel the offsetting forces so directly. The signal your brain gets is the changing angle your phone needs to hold pitch. Itās clear when the ānose stableā angle of my phone is way off, but feeling itās off is different from having a reference for exactly where that nose stable position is. In a real aircraft, take you hands off the yoke, and itās very clear - itās where the nose doesnāt move with hands off; no force on the muscles while holding the yoke.
Itās the nature of the input device. I like the way IF includes trim. I think itās the best possible compromise for simulating reality within the given limitations of our input devices. It lets you see how it really works, even though the feel must be somewhat different.
Sometimes I tell myself that calibrate is auto trim.
(edit: As for your topic title, for take-off anyway, take-off trim corresponds to pitch neutral at the best rate of climb speed. For that to be true you will feel nose heavy from lift off until acceleration to that speed. Seems reasonable from a stall-on-take-off avoidance perspective? - ease off the yoke as you accelerate rather than having to push it. You apply relaxation rather than more tension to adjust as you accelerate leaving the ground)
I think because if planes were tail heavy, on the ground thereād be a chance of the tail striking the ground.
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