Why can AH planes climb when missing a wing by bank ing 90.....

[Les Paul]

Hm. I've managed to do this several times whilst piloting the 109 series and there's only a few things I have to say about this. In fact, in my last sorty, I was flying for all of a minute with half my wing gone after a collision.

One is that at the moment your wing gets clipped down to half size you must be already going level or something close to otherwise you simply spin to your death. [Note you can still be level and turning (As long as your AoA is not high or even marginally moderate), or in a roll.] What I mean by this is the vector of your plane is roughly parallel to the ground/ perpendicular to gravity, whatever you want to call it.

You must be incredibly quick on balancing your plane out, or you'll lose your chance to stay afloat

You have to be going balls deep in terms of speed, like 400+MPH when your wing gets ripped off

From there its a matter of using rudder, and finding the new lift vector to kind of keep your plane afloat and managing E to stay as fast as possible.

If the conditions aren't near perfect when you lose your wing, you WILL plummet to the ground in a horrible case of drunken spins.

If your speed drops to low you will plummet. If you cannot maintain that soft AoA you will plummet.

You are pretty much stuck in a straight line doing a very shallow and low frequency wave, as the slightest change in your yaw, pitch, and roll will cause you to plummet

All in all, it seems realistic to me. If you can't finish off a plane with half a wing, the problem is not with the physics (As Skyyr and Hitech explained very technically) but with either your piloting skills, or your marksmanship.

Every flight-sim I ever had you could keep your plane (Unless its like... Some Goliath Boeing or crap civilian plane) going in a straight line with one wing severely damaged/broken/or in this case half missing (Half-there if your the optimist!) You could only really execute a shallow pitch climb, or a shallow pitch dive anything else and spinspinspinspinspin.

Imagine dropping a brick from 10m. It would hit the ground in 1 second.

But if you were to launch that brick with a level trajectory out of a cannon at 1,800m/s from 10m in the air I am willing to bet that the brick will take slightly longer to hit the ground. And it doesn't have any wings at all!

All these pilots are doing is using their remaining control surfaces to maintain their current momentum for as long as possible.

It would be one thing if they pulled out of a 15+ degree dive or climb with 1 and a half wings. Then I would think there is maaaaaybe something fishy.

[Estes]

I always get a chuckle when Hitech himself comes in, explains it half a dozen times and they still call BS. 

[FLS]

Les Paul the OP is talking about climbing knife edge with half a wing not flying level with half a wing. Next time you lose half try 50% flap extension. That should save you until you slow down to land. Flaps will decrease the lift imbalance as well as increasing the coefficient of lift.

[kvuo75]

But if you were to launch that brick with a level trajectory out of a cannon at 1,800m/s from 10m in the air I am willing to bet that the brick will take slightly longer to hit the ground. And it doesn't have any wings at all!

I'd take that bet.  it might tumble a certain way occasionally that makes it "fly" momentarily, but averaged out, its gonna fall at the same rate as the dropped brick.

[Brooke]

Okay, this has given me an extreme curiousity...how does one get the lift and drag coefficients for things likes the fuselage alone of a WWII airplane?

Friday night with kids asleep -- so, I'll take a crack at it. 

One could do it computationally, but it would require more work than I can put into it.  One could do it in a wind tunnel, but that's out.  Or, one can always do an estimation.  That's within my grasp.

For a lifting body, L = 0.5 * rho * v^2 * S * C_L, where rho is air density, v is velocity of the aircraft, S is reference area for the object generating aerodynamic lift, and C_L is the coefficient of lift for that object.  For wings, it is customary for S to be mean chord times wingspan.  For knife edge, the fuselage is doing the aerodynamic lifting, and I'll take S to be 0.5 * (fuselage diameter at nose of aircraft) * (aircraft length) = 0.5 * d * l.

For thrust, from propeller theory (see http://electraforge.com/brooke/flightsims/aces_high/stallSpeedMath/turningMath.html ), T= eta * BHP * 375 / v, where eta is propeller efficiency, BHP is HP of the engine.  For props with good ability to absorb the power of the engine, eta can be approximated reasonably well by knowing the advance ratio (J) and the power coefficient (C_P):  J = 88.0 * v / (N * D), where v is aircraft speed in mph, N is prop rotation in RPM, and D is prop diameter in feet; and C_P = 52.5 * gamma* BHP / [(N / 1000)^3 * D^5 * rho / rho_0], where gamma is fraction of full power being applied, BHP is engine brake horsepower, N is prop RPM, D is prop diameter in ft, rho is the air density, and rho_0 is the air density at standard sea level; and by using this chart:


I'm going to use a Pitts Special as a reference aircraft to see what a fuselage C_L is (as I can look at this video): 
http://www.youtube.com/watch?v=xvn_PTs0e5Q
And use these as references:
http://www.mt-propeller.com/pdf/stcflyer/FL003US.pdf
https://en.wikipedia.org/wiki/Lycoming_O-540
http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/ffae5a2bb5506dcc8625747a00650001/$FILE/1E4.pdf
https://en.wikipedia.org/wiki/Pitts_Special
http://www.steenaero.com/Images/Aircraft/3Views/pitts_s1c_3-view_800x500.jpg
My Pitts estimates are:
v = 175 mph (approximate cruise speed for a Pitts Special)
HP = 300 HP
D = 7 ft
N = 2700 RPM
W = 1400 lbs
alpha = 30 degrees (just eyeballing it from video)
l = 19 ft
d = 95 / 516 * 19 = 3.5 ft

For this, J = 88 * 175 * / (2700 * 7) = 0.81.  C_P = 52.5 * 300 / (2.7^3 * 7^5) = 0.048.  J/C_P^(1/3) = 0.81/0.048^0.333 = 2.22.  Then, eta = 0.8, and T = 0.8 * 300 * 375 / 175 = 514 lbs.

At sea level, rho = 1.22 kg/m^3 = mass/vol.  The equivalent weight/vol in English units is 0.0762 lbs/ft^3 = mass * g / vol = rho * g, so rho = 0.0762 / 32.2 = 0.00237 lbs * s^2 / ft^4.  For using in, say, L = 0.5 * rho * v^2 * S * C_L, where L is in lbs, v is in mph, and S in ft^2, we want rho in units of lbs / (mph^2 * ft^2), which is rho = 0.00237 lbs * s^2 / ft^4 * (5280 ft / mi)^2 * (1 hr / 3600 s)^2 = 0.00510 lbs / (mph^2 * ft^2).

L = W = 0.5 * rho * v^2 * S * C_L + T * sin(alpha).  1400 = 0.5 * 0.00510 * 175^2 * 0.5 * 19 * 3.5 * C_L + 514 * sin(30 deg).  1400 = 2600 * C_L + 257.  C_L = 0.44.

OK, so my estimate is that a fuselage has a C_L of 0.44.

Now let's see what v we need on a Brewster to keep level in knife edge at the same 30 deg.  For a Brewster, from America's Hundred Thousdand, by Dean:
HP = 1000 HP
D = 9 ft
N = 2200 RPM (had a gear ratio of 1:1)
W = 5500 lbs
l = 26 ft
d = 10 / 58 * 26 ft = 4.5 ft

So that I don't have to do a lot of algebra for a nonlinear equation, let's see if we can assume eta = 0.8 for the Brewster.  Assume we'll need to be going at least 200 mph.  In that case, J = 88 * 200 / (2200 * 9) = 0.89.  C_P = 52.5 * 1000 / (2.2^3 * 9^5) = 0.084.  J / C_P^(1/3) = 0.89 / 0.084^0.333 = 2.04, and eta = about 0.8 again.  So, we are OK.

Then, T = 0.8 * 1000 * 375 / v.  W = L = 5500 = 0.5 * 0.0051 * v^2 * 0.5 * 26 * 4.5 * 0.44 + 0.8 * 1000 * 375 / v * sin(30 deg).  5500 = 0.0656 * v^2 + 150,000 / v.  0.0656 * v^3 - 5500 * v + 150,000 = 0.  Solving numerically for v gives a root at v = 275 mph.

So, with all of these estimates, it shows that a Brewster can maintain level, knife-edge flight at 275 mph or more.

This is all assuming that I haven't made any math errors.  Also, if you think any of my numbers are wrong (like prop diameter of the Pitts Special, or whatever), plug in your own numbers and have a go at it.

[Brooke]

By the way, in the above, I don't expect the estimate to be correct within 10 mph or something that close.  It's just a rough estimate coming up with the number being well less than 500 mph and a lot more than 150 mph -- i.e., doesn't sound too outrageous compared to what we see in AH.

[Les Paul]

Les Paul the OP is talking about climbing knife edge with half a wing not flying level with half a wing. Next time you lose half try 50% flap extension. That should save you until you slow down to land. Flaps will decrease the lift imbalance as well as increasing the coefficient of lift.

Hm, maybe I didn't explain that clearly. I know he is talking about knife edging. What I meant by near level was for the planes trajectory, not the wing line. (I'm not a pilot, so my terminology is shaky. I have to resort to tard ways of explaining things I always just assumed that flying level meant you were traveling perpendicular to gravity, regardless of planes orientation. That's why at high altitude auto-level pitches your nose up. You're plane's wings are technically no longer level, but your flight path is still level.) Or if he used too much elevator trying to turn his knife edged plane, he would spin out.

The only speeds that I can fly my 109 with half a wing and keep my wings level is in the 450 to 400 mph, otherwise you're plane starts to naturally begin to roll on its side. Despite applying all the rudder in the world. The one aileron you have left can aide the rudder, and you can maintain level wings for longer, but I wouldn't advise adding all that drag.

While I was rocketing around in my 109 for a few minutes without half my wing, I was probably banked around 75 degrees maximum, 45 degrees minimum pending current speed/climb rate (The 109 can't knife edge for nada, so I needed some elevator to aide me) shifting between a -5 degree dive to maybe a +5 degree climb (Probably an even smaller margin, more like -5,+2)  by using full rudder and relaxing it only slightly, every now and then you shallow out your bank, before steepening again. I have never never seen a half wing (Knife-Edged or Not) sustain level flight indefinitely or sustain a climb in game (He uses the Rv-8, which is only available offline.), its always that slow frequency wave I see people doing, giving the appearance of sustained level flight (From out of plane looking at the plane) at varying degrees of bank pending the plane. Some of these planes have crazy weight/thrust ratio's and beefy rudders, low wing loading, so I can see certain planes being able to bank a full 90 degrees and use rudder to maintain level flight or a shallow degree climb for extended periods of time.

In essence, that plane can only maintain its momentum from when it lost half its wing, and any sudden shift in the vector of your planes momentum can and usually will cause you to spin out.

I was also trying to explain that if the guy was in a vertical climb/descent (Parallel to Gravity) when he lost his wings, his rudders, elevators, and ailerons would not have the necessary strength to stabilize the plane and get it flying perpendicular to gravity again. They only have the strength to keep your momentum perpendicular to gravity for a short period of time. In essence, you are now a projectile with some limited control flaps.

My half-wing 109 however plummets/spins out when I get around 250mph no matter what, much to fast for me to deploy flaps.

[Les Paul]

Oops, double post. Meant to edit.

Also, Icepac changed what he meant with his original posting several times. The title suggests that ALL planes in AH can do this. Then 1st and 2nd page, he goes into just using rudder to stop yourself from auguring with half a wing (No mention of knife-edging.) then he brings up some crazy convo about the Rv-8 which doesn't appear in game. He never suggests which planes have the ability to do this, and which do not, provides no video evidence of planes doing this at a full 90 degrees pure knife edge half-wing climbs, then he goes into he only made this post because he thinks the rudder authority is fishy.. I am not sure the OP knows what his own thread is about.

[Debrody]

My half-wing 109 however plummets/spins out when I get around 250mph no matter what, much to fast for me to deploy flaps.

As long as youre still fast, point your nose up high, chop throttle to slow down, then open full flaps to regain control. It works.

[ink]

what it if were two lbs of $100 bills?

$90,800

[SFRT - Frenchy]

So what exactly  is the max LCO of the fuselage  of an fm2?

I assume you must have done the calculations because you KNOW ours is not correct.

HiTech

HiTech

Oh for Christ's sake HiTech, get a hold of yourself. Learn how to take a critic. You always get defensive and throw your aeronautical engineering studies to intimidate the crowds. You can wave your fancy aerodynamic formulas all you want, they are still severe flaws in some aspects of AH flight modeling, such as the P47 nose getting 'stuck' wobbling in the sky in a stall nose high for 5 secs plus. All the planes I ever flew, including my 16,000lbs Metro or lately 10,000lbs Pilatus with 1,600HP ... when you stall at any angle : the nose goes down quicker than a Thai hooker.

Anyway, still a hell of a game that's why I've been giving you my money for the last 14 years. Please put your ego aside and listen to your customers concerns about FM even when they identify the shortcomings of the FM.

[danny76]

I'd take that bet.  it might tumble a certain way occasionally that makes it "fly" momentarily, but averaged out, its gonna fall at the same rate as the dropped brick.

^^^ this

[Brooke]

I think that HiTech is right.  Folks frequently say that a particular thing is wrong when it isn't.  Sometimes it's like someone saying that a machinegun can't possibly shoot more than one round every 10 seconds and thus that the machineguns in AH are modeled incorrectly.  That's like this knife-edge business.  For sure some aircraft can fly for a while knife edge.  Many air-show viewers have seen this.   There are videos of it.  And you can work out the math of it to show that it is feasible and that, if it weren't possible in the game, the game would be wrong.

With regard to stalls, some WWII fighters can have quirky stall behavior, depending on how the stall is entered and what control motions the pilot does, behavior including nose-high oscillations.  Design of civilian aircraft puts great emphasis on docile stall behavior.  WWII fighters, not nearly as much.  They also have 1500-2000 HP engines and huge diameter props, generating an enormous amount of torque, gyroscopic forces, and P-factor.

Here is a video titled "P-39 Tumble and Spin Tests".  Check out the footage starting at 6:37 in:

http://www.youtube.com/watch?v=BWwI6gZw67g

Here is video of a Mosquito getting into an unrecoverable and fatal stall:

http://www.youtube.com/watch?v=Ag5ut3tP3ZM

[FLS]

Oh for Christ's sake HiTech, get a hold of yourself. Learn how to take a critic. You always get defensive and throw your aeronautical engineering studies to intimidate the crowds. You can wave your fancy aerodynamic formulas all you want, they are still severe flaws in some aspects of AH flight modeling, such as the P47 nose getting 'stuck' wobbling in the sky in a stall nose high for 5 secs plus. All the planes I ever flew, including my 16,000lbs Metro or lately 10,000lbs Pilatus with 1,600HP ... when you stall at any angle : the nose goes down quicker than a Thai hooker.

Anyway, still a hell of a game that's why I've been giving you my money for the last 14 years. Please put your ego aside and listen to your customers concerns about FM even when they identify the shortcomings of the FM.

Nice rant but I don't think it fits this case. The OP has a reputation for making claims he can't back up. The aircraft in AH can only zoom climb knife edge. The half wing is beside the point.

[SFRT - Frenchy]

Alright then, carry on chaps