FM - IL-2 vs AH

[Kweassa]

109G-2 comes in right with Stalingrad.

 The difference between 15mms and 20mms are immense in IL-2.
 A good half~one second burst on IL-2 fuselage  with  109G-2s
 knock out enough material two convince the AIs to jump.

 In the case of Overheating, I also believe it might be  a  serious
 problem. But the question is, do those  planes  really  overheat
 THAT QUICKLY?

 And about the accelerations. If German planes like 109G-2s and
 190A-5s can't accelerate worth crap like currently in IL-2, I'd hate
 to think what US planes and RAF planes would be portrayed like
 if they are ever introduced within IL-2 standards.

 I think the post by Sorrow [S=A] explains and tells us  lot  of
 helpful info, but I don't think I see anything about the accelration
 issues.

[Wotan]

Voss I am planning on it..........

I let ya know maybe I look ya up......

[Toad]

I'd be basically amazed if anyone designed an aircraft where the trim panel / stick force relationship was such that the "average" pilot could find himself in a position where he was too weak to "overcome" the forces generated by a particular trim panel with the stick or rudder pedals.

However, there's an awful lot of WW2 aircraft out there, maybe there are one or two that are that poorly designed. I'd think anecdotal evidence about such a plane would be common and usually with obscene vulgar words used to describe such an aircraft.

Trim is a secondary flight control. This cannot be repeated often enough. Trim is not normally used to "fly" the airplane, but rather to relieve stick forces to reduce/avoid fatigue.

The only time someone would "fiddle" with trim enough to get it totally "hands" off would be on "cruise" legs. There's no need and absoutely no time to be totally trimming hands off while fighting. You have a stick and rudder to move the nose that are far, far more powerful than any trim panel on the aircraft.

Also, remember that trim is constantly changing as fuel burns off (weight change), with throttle/rpm changes or airspeed changes. "In trim" is a "moment to moment" thing.

I'd almost guarantee that in any WW2 dogfight the pilot had one hand on the stick and the other on the throttle quadrant 98% of the time. Maybe a couple quick turns of an elevator trim wheel as major changes in speed resulted from climbs or dives now and then. Probably NEVER on the rudder or ailerons.

I'll never forget my IP in T-38's telling me from the backseat "mister, I want this airplane totally trimmed hands off in 30 seconds. Put both hands up when you're done". Well, the 38 was real stable in cruise and easily trimmed. After you had some time in it you could trim it hands off pretty quickly. So, I trimmed and held my hands up.. it went perfectly straight for about 10 seconds then started a slow roll to the right. I got screamed at and had to do it again. Same thing. And again. Same result.

Finally, he had me trim it out, put my hands up and then he said "lean all the way to the right against the cockpit rail".  I did.. the airplane started a real slow roll to the right in a few seconds.

He had just be letting me trim it out and then leaning to the side. That's all it took, just that little shift of weight. He thought this was absolutely hilarious.

(Yeah, Larry... I still remember that one and the "hoo-hah" check too.   )

Moral of the story? Concerns about trim are usually way overmodeled.  

[Creamo]

Trim is not normally used to "fly" the airplane,

Dunno 'bout that. On approach in a civilian turboprop, trim is almost  the whole elevator input to achieve a smooth balance to glideslope.

Now maybe a jetliner is diffrent, I doubt it, and who am i to differ?

I agree you elude to stick input in combat is 98% of the time the controlling factor, but don't discount when that T-38 wasn't stable after setting it up and you had to trim it.

The trim input AH seems to model achieves this very small balance of control pretty well.

Or were you not discounting this?

[Toad]

Flying precision approaches (in anything):

You set the desired pitch attitude with the stick and relieve the resultant stick pressures with the trim. Almost always elevator only because the aileron and rudder pressures are so light as to be insignificant. However, sometimes a little rudder trim is nice, especially with a "bent" airplane.

Of course, if you're in the mood, you can just hold the pressure without trimming. You generally get a better, more precise approach if you trim however. This is due to a lot of reasons but mainly because there's other stuff going on besides pure stick and rudder flying that momentarily distract you.

And we're talking about simply flying straight down a 3 degree glideslope here, not maneuvering during ACM. Trim IS useful for a constant, nearly unchanging flight condition. THAT is the point of trimming, in fact.

Look, trim is defined as a secondary flight control by the Feds.

Yeah, you can fly down the glideslope using only minor adjustments to elevator trim... on a calm day, AFTER the aircraft is fully configured and on speed. Basically, a constant, unchanging flight path.... that's what trim is really for; relieveing the stick pressures and reducing the number of things you have to be worrying about at one time.

Trim is NOT a primary flight control.

Will a WW2 fighter fly if you remove the elevator trim panel from the airplane? Absolutely YES.

Will a WW2 fighter fly if you remove the elevators from the airplane? Absolutely NO.

[Vortex]

I think Sorrows covered most of the issues well. A couple points I'd excentuate.

IL2 nicer points:

Overrev: This should be in AH, it IS a crucial factor of pushing a plane to the envelope and beyond, and it would add a great dimension to AH. All of a sudden those slower P&W rides like the Jug and F4 have a VERY real advantage over the Runstangs, D9's, and La7's (the latter's radial wasn't nearly as robust as the P&W) in drawn out fights.

Graphics: IL2's graphics are indeed nice, but I wouldn't want them in AH. For online sims framerate is everything. I much prefer a slightly older graphics engine and enhanced frame rate for something like AH.

Gunnery and damage: One needs to be careful here as I think they do a bit of "gamey" stuff in IL2 to help give the appearance of a historic gun model. No hard testing on that mind you, just an observation. Nevertheless IL2 does have a good feel to its gunnery. Damage is a nice touch, although I'd tend to agree with others that I don't think the _effects_ of the damage are that stringently modelled. Nice eye candy though.

Stalls: The planes actually mush out in IL2, very much like how a high speed stall should feel. AH doesn't really model this, or at least not to that degree.

IL2 minuses:

Trim: This is a mess imo. IL2 is a perfect example of trying to take "realism" too far. Keep an A/C in trim is a constant battle with the big difference over an actual a/c being you can't "feel" a thing in a sim. Moreover inputs to one degree or another DO significantly limit the maneuverability of the plane along that axis. AH is leaps and bounds ahead here providing a nice compromise between playability and this concept of realism. IL2 is pretty much exactly what I wouldn't do in a sim wrt trim.

Stick config: I don't know what the exact cause is here but I've yet to see a game that is so sensitive when it comes to stick config. Get it wrong and you will see some of the strangest effects ever in a sim. As an example my first SCALING (not deadband or the like, although its absolutely amazing how much slight adjustments in those settings can mess things up too) setup caused limitless inertia along the roll axis of the plane. Start a roll, let stick come center, and the plane would continue to roll infinitely until you applied offsetting pressure...at which point it would start rolling back the other way. You can tweak a lot of this out but it takes much time and a bit of luck to be sure. In the end you never really know if the effect you're seeing in game is the result of the model itself, or the porked stick config. Another "Top of the List" for the worst I've seen in a game. Worth noting I use an older analog stick. It works fine in every other sim I've tried though, including AH.

Other than some wizzy graphics in IL2 I don't really know what all the fuss is about. Its got some nice features, its a nice change to be sure, but it certainly isn't lighting my sim world afire.

[Creamo]

that's what trim is really for; relieveing the stick pressures and reducing the number of things you have to be worrying about at one time.

Of course, which I use every time I try and trim the Dora out on the flat merge, and any other envelope/speed/'angle it demands so she aint so dirty.

Some use Combat Trim to achieve a desired result, i choose to just work in what the sim provides for the simulation itself. Good trim characterists. See?

[Toad]

I see you left out the part about "constant unchanging flight path" which is really the relevant part with respect to trim use and ACM in the game.

IMO, trim is one of the aspects of the AH FM that doesn't really make the grade. Trim effects are WAY overmodeled I think. A minor spin of the trim wheel shouldn't put you in a 1500 FPM climb.

After flying the P-38 for a tour, I am more convinced than ever. If you don't constantly work the manual trim the airplane barely performs. Sorry, that's just not right. ELEVATOR moves the nose.. not trim. Trim just relieves stick pressure.

Trim is not a primary flight control. ELEVATOR moves the nose. Elevator trim relieves stick pressure.

Combat trim, provided by the game programming, is merely an attempt to moderate the overemphasis unwittingly placed on trim intially... in my opinion, of course. To a degree, it helps do that. However, relying on Combat Trim in a P-38 (and probably others as well) provides significantly less performance than is available with manual trim. So, it's not entirely effective.

Now, if folks want to believe that the essence of being a true killer fighter pilot is mastery of the elevator trim wheel.. who am I to whiz in their wheaties? There's people who still believe in Santa Claus and the Cardiff Giant too.

[Creamo]

I lost you on the Holiday character and I think comic book ref.

Regardless, trim should damn near fly the plane in the various axis in level flight. And help at least stabilize it in any flight envelope. To what degree? Dunno, ask Charles Yeager.

The velocity of the trim inputs is a argument I never commented on, nor have the batteries to point/counterpoint. Im tired.

I like what AH does with it though.

[Khavren]

Actually Toad...you're kinda wrong.

Adjusting flight controls using the trim wheel is only ineffective because of the gear ratio (so to speak we're actually talking cables and pullies) from the trim wheel to the actually control surface (or trim tab of the surface) is designed to give the pilot an easier "Fine tuning" ability.

However full control of flight Can be achieved.  In fact it's done all the time.

Autopilot systems fly aircraft through use of the aircraft trim.  Autopilot doesn't move the control surfaces directly, but indirectly through use of the trim tabs.  And don't think for a moment we're merely talking 'Attitude Hold' or 'Heading Hold'.  Terrain following, WARS, GPS Waypoint Following, and my other autopilot modes are perfect examples of this.

Plus many aircraft have electronic trim wheels, (usually larger aircraft with large control surfaces) which really zip that trim wheel quickly.

Granted I'm using more modern examples, however the Trim concept is still the same.  (of course all the planes in AH have autopilot modes anyway...go figger).

[Toad]

You are indeed talking modern aircraft and not all of them work as you say. Some autopilots do work through trim tabs... and some move the actuator that's attached to the actual control surface. The latest commercial technology autopilots mostly reposition the control surface hydraulically, eliminating the need for a tab. Additionally, when hand flying such an aircraft, 'trimming" is merely using hydraulics to reposition/redefine the "neutral" position the surface.

If you're going to tell me that fully deflecting a WW2 trim tab will eventually move the associated control surface to full deflection, I'll disagree. Some may have that much authority but I seriously doubt if very many would. It would be the definite exception, not the rule.

Ever try to takeoff using only elevator trim for pitch? It can be done (in some but not all weight/CG conditions) but it's not as efficient or fast as just pulling back on the stick. Why? Because the tab probably has enough authority to get you into the air but not as fast or efficiently as deflecting the control surface.

Ever wonder why they don't TEACH "rotate with trim only on takeoff"? I don't.

Beyond that, have you ever encountered a WW2 trim tab so powerful that the stick could not be used to overpower it? In other words, an elevator trim tab so strong that when the tab is trimmed full up using forward stick is insufficient to make the aircraft nose go down?

Trim is NOT a primary flight control.

[Sorrow[S=A]]

Thanks Toad, I was waiting desperatly for someone to FINALLY come out and say that.

Beyond that, have you ever encountered a WW2 trim tab so powerful that the stick could not be used to overpower it? In other words, an elevator trim tab so strong that when the tab is trimmed full up using forward stick is insufficient to make the aircraft nose go down?

This has been my major question about Il-2 trim models.

At max value +/- there is so much trim recenter that the pilot cannot obtain full deflection (even in slower speeds). This has been my query all along- can an elevator trim tab exert enough pressure to do this? (It is NOT like this with elevator&rudder AFAIK).

In looking at this I am left with two observations.
#1 The 109 we know had leverage problems and force was limited to what? 40-60lbs? Could the trim exceed that? We know it could exert enough force to pull the plane out when the stick could not- unless it was just the gear ratio on the tab allowing any control input to raise the nose.

#2 I honestly don't know how much effort it took to control the fighters we play with IRL. The P-38 needed hydraulics to move ailerons- was that because a normal person wouldn't have been able to do so effectivly? What about the P-47? Too many questions

[Voss]

From what I've read:

The 109's trim tabs on elevator and aileron were not adjustable in flight. The rudder had a small trim tab that was found to be ineffective and was assisted by additional (ground adjustable) tabs. Well, there were a lot of 109's, but I don't think any had aileron/elevator trims adjustable in flight.

The P-38's ailerons were boosted to assist the pilot. They were about as heavy as a Lear 25 is today, before the change. Everyone says that a four hour flight in a Lear 25 will wear you out. The autopilot fails constantly on nearly every one of them, so the PIC is constantly holding a pretty good load. This, no doubt, helped a great deal on those long missions.

I don't think either it or the Jug were so heavy in control as to cause a real problem, unless in compression.

The 109, however, was limited in lateral application of force from the pilot to the stick. This was because of the narrow cockpit, as the pilot could not elevate his elbow enough to gain proper leverage. In the Blonde Knight's case, he was so over-sortied against the Russians that, after landing. he was frequently asleep before the ground crew could remove the canopy. The 109 was that abusive.

In contrast, every Luftwaffe pilot (or British for that matter) that had a chance to inspect an American machine, was surprised at the room available in the cockpits.

109's never had to contend with the really long missions, though.

Oops, wandered off of trim tabs.,,

[niklas]

Originally posted by Voss
From what I've read:

The 109's trim tabs on elevator and aileron were not adjustable in flight.

Elevator trim was possible. You could change the AoA of the whole stabilizer. If you compare it to current highspeed designs (which often uses the whole stabi as an elevator), than you can see that it was the most advanced trim system at this time.

 The rudder had a small trim tab that was found to be ineffective and was assisted by additional (ground adjustable) tabs. Well, there were a lot of 109's, but I don't think any had aileron/elevator trims adjustable in flight.

It was a flettner tab / spring tab and not adjustable from the cockpit like a trim tab.

The 109, however, was limited in lateral application of force from the pilot to the stick. This was because of the narrow cockpit, as the pilot could not elevate his elbow enough to gain proper leverage. In the Blonde Knight's case, he was so over-sortied against the Russians that, after landing. he was frequently asleep before the ground crew could remove the canopy. The 109 was that abusive.

I´m tired to hear over and over again the same BS. Was the cockpit of the spit much larger? Yak-3? When the english test pilot has no power in his arms he shouldn´t blame the 109. And those comments refer to the aillerons of the E btw, the F model already had new designed aillerons with Frise effect.
The 109 was a small aircraft, you logically have smaller control surfaces and smaller control forces. This way it could go with a smaller stick and less stick deflection.
You can also balance the control surfaces of a P38 in a way that you could fly with the stick of a 109, but in some situations you would risk overbalance. The control surfaces of the 109 were not as good balanced as other designs imo, but the forces were afaik positiv in most (if not all) flight situations.

In contrast, every Luftwaffe pilot (or British for that matter) that had a chance to inspect an American machine, was surprised at the room available in the cockpits.

Well, they were even more suprised that the P47 performed like a lame duck near ground with such a powerful engine. What do you think, could this be somehow related to the size?  The airframe of the P47 actually had a larger diameter than some civil passenger aircraft.

by sorrow

#1 The 109 we know had leverage problems and force was limited to what? 40-60lbs? Could the trim exceed that? We know it could exert enough force to pull the plane out when the stick could not- unless it was just the gear ratio on the tab allowing any control input to raise the nose

This is simply not true. The 109 elevator was designed for at least 85kg/ 187lb "elevator pulling" and 70kg /154lb "elevator pushing". The rudder was designed for 150kg/ 330lb each feet.
And in the 109F 50lb aileron stickforce was reached in 10k feet at a speed of ~350mph, this is comparable to many other designs.

niklas

[Sorrow[S=A]]

Niklas- 50lbs would be in the "range" I quoted of between 40-60lbs. 350mph@10k would be an operational flight speed too would it not? I was not referring to the ability "on the ground" after all.

And I was aware of the changes by the F and later G model, these IIRC affected mostly the ailerons at higher speeds. The Elevators still had lockup issues and required trim to regain control in fast dives.

My question still stands- with this in mind could any of the 109 model had an issue where at 200-350mph the trim tab could create enough force the pilot could not move the stick it's full amount?
This is not about the 109, it's a question about trim with the 109 as a starting point. Don't get sidetracked!