Modders: is differential braking impossible or improbable? - Printable Version

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+---- Thread: Modders: is differential braking impossible or improbable? (/showthread.php?tid=58413)

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Re: Spitfire Brakes - beercamel - 05.12.2009

Nummy Wrote:I am interested in a program that duplicates real spitfire brakes. English airplanes of the WWII period did not have toe activated brakes as did te US and LW planes, but had a bicycle like lever on the control column that released compressed air into the main wheel brakes proportionally to the amount of rudder input to one side or the other.
In other words, to activate the left brake, the left rudder was pushed, then the lever on the joystick sqeezed, and the air flowed to the left brake, giving braking action. If the rudder was centered air flowed equally to each wheel brake and onehad a parking brake so to speak.
I had the opportunity to fly a spitfire simulator on a trip to England. It had been flown earlier by two spitfire pilots from the RAF Battle of Britain Memorial Flight.

http://www.simcontrol.co.uk/offboard.htm

It took some tweaking--read the Review--but the two pilots said, "If you can fly this, you can fly the real thing".
But, they said, the braking was very unrealistic, compared to an actual spitfire. The problem is, they said, that the rudder on a spit is totally ineffectual for steering on the ground until a speed of 40 knots or so is reached. Up to that point, all steering is done with the brakes. So far as I know, no program yet exists in any Flight Simulator program that realistically simulates real spitfire braking.
So it seems to me that there is a crying need for an accurate spitfire (Hurricane, etc, which is the same) braking program, for all of us who desire ultimate realism in our flight sims.

Nummy,

You already have that available... In the 'Normal' IL2 game!

I have flown some WW2 British aircraft (In Real life).. there aren't brakes on the rudder pedals... but there is a lever on the stick that applies brakes when squeezed... the amount of braking applied to each wheel is PROPORTIONAL to how much rudder input you have... If rudders are neutral, and the brakes engaged.... then equal braking on each wheel is the result.. If you have full left rudder input.. and you apply the brakes the vast majority of the braking action will be applied to to the left wheel with little or none to the right..

The same in IL2..

If you put in full left rudder and press the 'B' key (either by keyboard or macro program on CH or Saitek rudder pedals..) you get EXACTLY the same result.. the more/less rudder input the more/less braking you get on that wheel. Il2 also very closely emulates the tail wheel center 'breakaway' when you want a pivot turn... just as in real life aircraft.. Stop the aircraft.. apply full rudder and brake.. and add power (Don't nose over!) to 'hold one wheel in position and rotate around it as the tail wheel goes into full caster.. just like in REAL LIFE.. ON AIRCRAFT THAT HAVE THE ENGLISH AND RUSSIAN STYLE BRAKES..

US and German aircraft were/are a little different but for tail wheel aircraft this is close enough.. And with the macro programing on CH Rudder Pedals.. is pretty close to the US system except that rudder must be used in conjunction.. which is what would/should be done in real life..in real life you never (well almost never) use ONLY the brakes as it will cause more wear than necessary, and in some cases with the older aircraft, can cause a problem if one locks up..as some of the older drum designs are prone to..

The P-38 single engine taxi in IL2 is pretty wrong.. although, in real life, it is more difficult in twins to single engine taxi than most non-pilots think.. possible .. but not nearly as easy as two engine taxi..

BC

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- Ironwrench - 29.05.2010

Having flown a number of the real aircraft, both single and multi-engine, I find taxiing and braking these sim aircraft to be most unrealistic. In the real aircraft, unless you are on soft surfaced runways like grass or mud, once the bird is rolling it takes little power to keep up momentum. Sim aircraft require a highly unrealistic amount of throttle to overcome inertia and keep the aircraft rolling. When the aircraft is finally moving, it then continues to accelerate requiring reduced throttle, at which point the aircraft immediately decelerates to a stop. When I was a flying ace, I used to fast taxi up to a parking stand, shut off the engine, and spin the aircraft around using the momentum. A few hundred hours later, I learned how few flying aces lived to retirement or at least stayed employed; thus, I became more judicious in my ground handling techniques. Now in a risk free environment of virtual airworthiness where all mistakes can be corrected by applying the escape key, I find I cannot indulge my former ground handling panache to impress the actors (nor can I escape the cockpit and head to the bar after a grueling flight. I thank the sim gods I can at least open the canopy and gulp down some fresh air).

Keeping the balance between throttle and brakes proves far more difficult in the sim than in real life. Had I used brakes and throttle in this manner on real aircraft, I would have worn out the brakes in short order and probably lost my seat for such heavy-handedness. Even driving smaller multis, while using a small amount of differential throttle, at slower taxiing speeds I invariably used brakes more than throttles. Such throttle usage is most effective during high-speed rollout and taxiing. The reason for this is that it is just as easy and efficient to use brakes as it is throttle for taxiing and shifting the throttles in your hand to the necessary degree was difficult compared to using the toe brakes. It must be remembered that on smaller twins the engines are closer to the centerline. For this reason, asymmetrical throttling requires more throttle input. At slow speeds, typically once the necessary amount of throttle is employed, it is already too much and the aircraft swings too far. Heavier asymmetrical throttle action comes into play more often on larger two and four engine aircraft like the C-47 and B-17 or when one wants to hard pivot the aircraft on a wheel, but as this tears up tires, one always allows for a small amount of forward movement as the aircraft is turned. Of course this hardly applies to nose-wheeled aircraft where one simple uses nose wheel steering to point the aircraft where they want it to go. The exception is in large, four engine aircraft where a judicious amount of outboard engine throttle can be used to assist a reduction in turn radius.

My other beef is turbulence when flying in weather. While I can understand turbulence being difficult to recreate in a sim, the rapid yawing action of the sim is most unrealistic and makes me feel seasick. Real turbulence is rather more like riding straight down a road filled with pot holes, an effect that would be difficult to recreate without some fancy hydraulic actuators. Even the legendary yawing effect of the old V-tailed Bonanza was tolerable once one became accustomed to it, but the sim yawing is like nothing I have ever experienced outside of having a damaged airframe. I have also experienced this yawing action under CAVU conditions in aircraft like the Bf-109. I find it hard to believe the real aircraft would have had a defect of this magnitude left uncorrected. The P-51D suffered from such yawing instability, which accounted for the small strake ahead of the vertical stabilizer. Most floatplanes also have ventral fins to alleviate this type of yawing instability induced by the floats. Obviously designers are quick to fix the yawing issue, so why do the sim aircraft suffer from this defect?

In any event, I would like to mention that I quit flying years ago. I was through with aviation until a friend of mine asked me to install IL-2 on his computer. After the installation, I tried the game and became addicted. For the last month and a half, I have done little else besides upgrade and fly missions. I always loved stick and rudder far more than procedural manuals, and I always wanted to fly WWII combat - this game allows both. Better still no need for lengthy checklists, runups or return to the ramp for some system failure. I have flown

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