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The Fokker DVII


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#41 Manny_Pfalz

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Posted 09 January 2012 - 14:07

There are FOUR forces of flight, not just one. LIFT is very important of course! But the evil twin of lift is DRAG. LIFT and DRAG are ALWAYS proportional. Then of course, there are WEIGHT and THRUST. No single force determines the superiority of one plane over another. The combinations are infinitely variable.
Concerning rotary engines, there are two things to consider, not just one. Counter-torque, AND gyroscopic precession. Counter-torque affects roll rate, gyroscopic precession is a force acting PERPINDICULAR to the axis of rotation, which CAN be used to increase turn rate, if handled properly.
Hope this adds to the discussion.
Cheers,
Manny
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#42 neuro

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Posted 09 January 2012 - 14:12

Forget about that. There's one force that keeps all planes in the air, and that's money.
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#43 Finkeren

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Posted 09 January 2012 - 14:34

Manny: Strictly speaking "weight" is not a force, "gravity" is. And I don't get this about lift and drag being proportional. What exactly do you mean?
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#44 Manny_Pfalz

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Posted 09 January 2012 - 15:15

Forget about that. There's one force that keeps all planes in the air, and that's money.

D'OH! Forgot about the most important one! Forgive me Jason! :lol:
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#45 Manny_Pfalz

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Posted 09 January 2012 - 15:23

Manny: Strictly speaking "weight" is not a force, "gravity" is. And I don't get this about lift and drag being proportional. What exactly do you mean?

Hi Finkeren,
Simply put, as lift increases, drag increases exponentially. It's the old power curve, there's no escaping it.
Weight is absolutely a force. Gravity is a vector. Otherwise, a plane with 100% fuel would behave the same as a plane with 10% fuel.
I wish I could provide a better example, I'm tired, I'll try again later!
Cheers,
Manny
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#46 gavagai

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Posted 09 January 2012 - 15:49

Manny: Strictly speaking "weight" is not a force, "gravity" is.

News to me! Why, then, are units of weight = mass*acceleration?

Aren't you conflating the "force" of mass*acceleration, and "force" in the fundamental forces of nature?
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#47 Finkeren

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Posted 09 January 2012 - 15:56

Yeah ofc, you're both right. I keep getting mass and weight mixed up in my head :oops: This is why, I'm not a scientist and should propably stay away once the discussion gets too technical, I can't keep my terminology straight :P I just can't help myself.
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#48 gavagai

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Posted 09 January 2012 - 15:58

It's an easy mistake to make when scientists use one word to refer to two separate things. ;)

What really kills me is that a kg is not the equivalent of a lb. A kg is the equivalent of a slug, and a newton is the equivalent of a lb. :o
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#49 Panthera

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Posted 09 January 2012 - 17:27

Well, there are two forms of drag, parasitic drag and induced drag.

Induced drag (Cdi) comes as a biproduct of lift and is therefore directly proportional to the lift generated pr. area (Cl).

Parasitic drag (Cd0) is the drag caused by the actual act of moving the aircraft through the air and comprises of skin friction drag, form drag & intereference drag, the former two being the only ones of importance for WW1 aircraft. Furthermore skin friction drag directly relates to the aircraft's wetted area, which is why the size of an aircraft is very important to the overall drag generated = the smaller the better in the case of a fighter. Where'as form drag, as the name suggests, relates to the shape of the aircraft.
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#50 Panthera

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Posted 10 January 2012 - 04:22

Ok, found some useful information regarding the airfoils. According to the book "A history of aerodynamics and its impact on flying machines" the types of airfoil used by the French and the British (Eiffel 14 & RAF 14) had a maximum lift coefficient of around 0.9 & 0.95, where'as the German Goettingen 298 airfoil had a maximum lift coefficient of around 1.38.

Based on that the relative wing loading of the Fokker DVII & Sopwith Camel are as follows:

Fokker DVII
Relative wing loading: 30.4 kg/m²

Sopwith Camel
Relative wing loading: 32.4 kg/m²
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#51 Panthera

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Posted 10 January 2012 - 04:27

By comparison the Fokker Dr.1's relative wing loading was a very low 23 kg/m².
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#52 LLv34Wmaker

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Posted 11 January 2012 - 19:29

Now ofcourse this comparison is open to critique and debate, seeing as no doubt a lot assumptions are being made, and ofcourse I welcome any additional insight on each aircraft.

850kg is too low for a loaded weight of the D.VII. Captured OAW-built D.VII had an all up weight of 959kg. The store page of RoF lists D.VIIF's weight as 904kg.

Other thing is that while Camel's wing's thickness ratio remains the same throughout the wing while D.VII's wing's thickness ratio changes. Estimating the Clmax of the whole aircraft based on the Clmax of the wing's center section will yield too high value for the aircraft's Clmax.

I've understood that the D.VII's airfoil wasn't any single Göttingen foil but Fokker's own modification of one, although for this purpose I'm sure that the Göttingen 298 is "close enough". Camel's profile indeed is or is very very close to the RAF 14.

Some airfoil data:

Göttingen 298: http://www.worldofkr....com/foils/1142" onclick="window.open(this.href);return false;">http://www.worldofkr....com/foils/1142

RAF 15 (closest in this library): http://www.worldofkrauss.com/foils/608" onclick="window.open(this.href);return false;">http://www.worldofkrauss.com/foils/608
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#53 Panthera

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Posted 12 January 2012 - 00:40

Now ofcourse this comparison is open to critique and debate, seeing as no doubt a lot assumptions are being made, and ofcourse I welcome any additional insight on each aircraft.

850kg is too low for a loaded weight of the D.VII. Captured OAW-built D.VII had an all up weight of 959kg. The store page of RoF lists D.VIIF's weight as 904kg.

Other thing is that while Camel's wing's thickness ratio remains the same throughout the wing while D.VII's wing's thickness ratio changes. Estimating the Clmax of the whole aircraft based on the Clmax of the wing's center section will yield too high value for the aircraft's Clmax.

I've understood that the D.VII's airfoil wasn't any single Göttingen foil but Fokker's own modification of one, although for this purpose I'm sure that the Göttingen 298 is "close enough". Camel's profile indeed is or is very very close to the RAF 14.

Some airfoil data:

Göttingen 298: http://www.worldofkr....com/foils/1142" onclick="window.open(this.href);return false;">http://www.worldofkr....com/foils/1142

RAF 15 (closest in this library): http://www.worldofkrauss.com/foils/608" onclick="window.open(this.href);return false;">http://www.worldofkrauss.com/foils/608

Not so sure about the weight, German sources list 850 kg for the BMW engined DVII IIRC. Anyway these old aircraft tended to get heavier the more they were used, simply because of moisture building up inside many of the wooden components.

As for the wing thickness you are right, the DVII's thickness tapered down towards the tip, but not by much, it went from 12 to 9%, for which the change in CLmax is a mere 0.02 to 0.04. So basically we're talking an average CLmax of 1.52 for the DVII's wings and an average of 1.05 for the RAF 15.

That having been said the RAF 14 had a CLmax of around 0.95, and I believe the Camel used the RAF 14 and not the RAF 15. I believe the SE5a used the RAF 15 airfoil.
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#54 Chill31

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Posted 12 January 2012 - 02:43

Panthera

I really dont think you are right about the RAF 14 (Camel) airfoil and here is why:

Please visit this thread and look at the Polar plot for the RAF 14: RoF test flight data

You will see a little chart in the top left corner that gives the coordinates in percent chord of the aifoil. Compare those to the NACA 4306 and you will see that they are much closer than the 2306. Given the 1933 test of the NACA 4306, it is much more reliable than the RAF 14 test in the linked thread. Clmax of 1.2 is probably much closer to the Camels actual CLmax than .95 or even 1.05(I dont know where you got .95 from though)

Even if we say the D7 was a 1.6 CLmax airfoil, it doesnt change my previous analysis very much. Id be happy to look at any data you may have though.
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#55 Panthera

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Posted 13 January 2012 - 18:50

Chill,

On the NACA chart the Clmax is listed as 0.54 at a low reynolds number (twice dynamic pressure), which normally means a Clmax of 1.08 at actual reynolds number the real wing would encounter.

A CLmax of 1.2 the RAF14 would never achieve, it was simply to thin with too little camber, and the sharp leading edge would limit the critical AoA.

Also keep in mind that the actual CLmax probably is lower than 1.08, seeing as thinner airfoils tend to suffer as the reynolds number increases.

Anyway the RAF 14 & 15 are very similar and probably have a similar Clmax, so a 1.05 CLmax for the RAF 14 seems reasonable, where'as the Goettingen 298 has a Clmax of around 1.60.
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#56 Chill31

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Posted 13 January 2012 - 21:09

A higher reynolds number means that the fluid is less viscous which means that it will not stick as well to the surface of the object over which the fluid is moving. This means that flow separation/turbulence is less likely to occur (ie stall). So you can see that a higher reynolds number increases CLmax for airfoils.

http://www.grc.nasa....H/reynolds.html" onclick="window.open(this.href);return false;">http://www.grc.nasa....H/reynolds.html

I also dont see the reynolds number on the RAF 14 NACA chart anywhere. Where did you find it?

Did you look at the camber of the RAF 14 compared to the NACA 4306? By look at, I dont mean visually compare them. I mean compare the coordinates of the wing.

If anything, I estimate the Camel CLmax with RAF 14 to be 1.08 or higher, provided you are correct about them using a low reynolds number which would explain the very low CLmax. The ability to manipulate reynolds number in a wind tunnel was not available until 1922 as far as I can tell from NASA's website.

I will compare airfoil data for the GOE 298, but I thought (unconfirmed) that the 298 was the Fokker DR1 airfoil…
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#57 Panthera

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Posted 13 January 2012 - 23:19

A higher reynolds number means that the fluid is less viscous which means that it will not stick as well to the surface of the object over which the fluid is moving. This means that flow separation/turbulence is less likely to occur (ie stall). So you can see that a higher reynolds number increases CLmax for airfoils.

Correct, but the expected double figure (when corrected for twice dynamic pressure) tends to be lower for airfoils with a thickness ratio of less than 6%, where'as like you mentioned it tends to be a little bit higher than expected for airfoils thicker than 10%. In short, I believe that under a normal reynolds number the RAF 14 wouldn't exceed the 1.05 figure in CLmax similar to the RAF 15 airfoil.

Anyway I am certainly sure that the RAF 14's CLmax can't be over 1.08, as I have yet to see such a thin airfoil with the same amount of camber and sharp leading edge have a CLmax of over 1.01.

Furthermore the RAF 15 actually has a more rounded leading edge than the RAF14, which normally leads to a slightly higher critical AoA and CLmax. So if anything I'd expect the RAF 15's CLmax, which is 1.05, to be higher than the RAF 14's which is listed as 0.95 in the book I mentioned.
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#58 Chill31

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Posted 14 January 2012 - 20:54

Here is the RAF 14 compared to the NACA 4306 (on left) and the RAF 15 (on right) by percent difference.

v 4306— vs 15
0— 0
-0.26—
-0.29— 0.09
0.06— -0.19
0.02— -0.8
0.15— -0.56
-0.1— -0.39
-0.36— 0.2
-0.41— 1
-0.3— 1.1
0.1— 1.14
0.63— 1.2
1.12— 1.15
1.26— 0.91
1.87— 0.49
0.68—
0 —0
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#59 Chill31

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Posted 14 January 2012 - 21:14

Through the first 60% of chord, the 4306 and RAF 14 are withing .5% of each other

Also, the NACA 4306 has half a percent less camber than the RAF 14 and the RAF 15 has .3-.5% less camber from 20 percent chord aft. I just dont buy it, based on this data, that the RAF 14 has a CLmax less than 1.08.

You can also reference this test report for RAF 15 data which shows variable CLmax from 1.05 to 1.14 depending on the reynolds number (wind velocity) and test site: http://naca.central....-report-309.pdf" onclick="window.open(this.href);return false;">http://naca.central....field.ac.uk/rep … rt-309.pdf
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#60 catchov

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Posted 15 January 2012 - 00:43

Yes! :P Now I get it. You make a compelling argument Chill. :S!:
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#61 Panthera

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Posted 15 January 2012 - 03:24

Chill,

The problem is that the NACA 4306 is a very different design from the RAF 14, for one featuring a more rounded leading edge than the RAF 14, which is a crucial difference. Furthermore the RAF 15, which is not only abit thicker than the RAF 14 but also has a rounder leading edge, and as such if anything should feature a higher CLmax than the RAF 14, features a CLmax of 1.05.

RAF14, 15 & 16:
Image

The Camel's RAF 14 features very little camber:
Image

NACA 4306 by comparison:
Image

As such I just can't imagine the RAF 14 can have a CLmax above the 1.05 of the RAF 15.
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#62 Manny_Pfalz

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Posted 16 January 2012 - 10:45

Yeah ofc, you're both right. I keep getting mass and weight mixed up in my head :oops: This is why, I'm not a scientist and should propably stay away once the discussion gets too technical, I can't keep my terminology straight :P I just can't help myself.

LOL! ME TOO! At least we made enough noise to get the gurus involved! Now we can either learn from them, or go back to sleep, as we choose! :S!:
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#63 catchov

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Posted 16 January 2012 - 23:36

I have no idea what they are talking about. :? Is it about planes ?
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#64 neuro

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Posted 17 January 2012 - 05:18

It is? I thought it was about video games…

Image
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#65 Panthera

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Posted 28 January 2012 - 10:36

It would be interesting to see what CLmax figures the developers used for the different aircraft ingame, compared to the real life figures:

Goettingen 298 CLmax: ~1.52
RAF 15 CLmax: ~1.05
RAF 14 CLmax: ~0.95
Eiffel 14 CLmax: ~0.92
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#66 catchov

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Posted 28 January 2012 - 12:10

It is? I thought it was about video games…

Image

So was Jaykwon right neuro ? And what happened when they did the wind tunnel tests in the lab ? Please don't leave us in suspenders. :D
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#67 piecost

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Posted 29 January 2012 - 02:22

An interesting discussion & I can't resist sticking my nose in. A few points:

1. I didn't know that the Camel used an RAF14 section (even though I have the Replicraft drawings!), so thanks for that.

2. Maximum lift for an aeroplane will not be the same as the maximum lift of its wing aerofoil. The finite wingspan of the aeroplane, biplane interference, fuselage lift/interference, lift loss due to control deflection, etc will change it.

3. I measured CLmax for the RoF aeroplanes:

RoF test flight data
post #16

(see attached graph). I do not claim that these numbers are accurate, but you can benchmark them from the SE5a flight model review, where A.P. states what the original value was (just over 1.0?). I found it to be 0.9 to 1.0. Note that I could not stall the DVII and DVIIf due to running out of elevator authority so they are based on an estimated stall speed. I thought that the DVII and DVIIf should share the same CLmax. Fuel and Ammo loads impact the centre of gravity position (CoG) which has a significant impact on CLmax. A forward CoG requires more download on the tail and hence a lower CLmax. The DVII and DVIIf have inconsistent changes in CLmax with aircraft weight, this I believe to be due to my estimation of the stall speed.

4. Based on the CLmax measurements, corner speed measurements and the RoF Store weights I calculated the maximum instantaneous turn of the RoF planes (see attached). Hence, there are a few errors building up here but the graph is still interesting (confusing?) Unfortunately, I don't have my graph plotting PC running at the moment or I would have removed the other planes and plotted a low weight case. Fuel/ammo loads are all important.

If my graph is to be believed; the Camel has about a 8º/sec instantaneous turn advantage over the DVII at its corner speed of 140mph and an unrealistic 9g! Turning at about 80º/sec it would take 45 sec and 10 turns to swap places with a DVII on its tail. Seeing the height loss when chasing the ace AI in the near corner speed descending spiral, this would need allot of initial height to complete.

5. The maximum turn rate of the Camel was tested/calculated:

Current ROF Airplanes Flight Model Data Topic.
post #37

The real corner speed of a Camel was about 5.4g to 6g, combat flight sims always perform more violent manoeuvres than reality.

6. More reality:

"February 1919 THE AERONAUTICAL JOURNAL page 58

CONTROLLABILlTY

Controllability of an aeroplane is mixed up to a great extent with stability; and it has proved even more difficult to measure. One of the simplest measurements that can be made is that rate of turn. It can easily be shown, that there is a smallest circle in which a machine can be turned. If the controls are powerful enough the diameter of this circle does not depend on the size or speed of the Machine. This is supported by experiment, though when we come to aeroplanes ,so large that the diameter of the smallest theoretical turning circle is approximately the same as a dimension of the machine, it will probably cease to be true.

The wings of the aeroplane will give the most lift at stalling angle and the lift will be the weight of the aeroplane multiplied by the ratio of the square of the actual speed and the stalling speed. If, then, the aeroplane is banked vertically this force will supply the necessary central acceleration, i.e., the mass of the aeroplane multiplied by the square of the actual velocity and divided by the radius. Therefore the minimum radius is independent of the mass or the actual speed, and is given, in fact by (stalling speed in ft/sec)^2 divided by the acceleration due to gravity. For a stalling speed of 40 m.p.h., say 60 ft/sec., the: radius is about 110 feet!

Many measurements of the smallest radius of turn which could be obtained have been made either by taking the time of a turn at a known speed, or by camera obscura observation; The maximum acceleration has also been measured directly. It was found that for a number of different aeroplanes the minimum radius obtainable was above the theoretical minimum but by an approximately constant percentage (20% to 30%).

This measurement is comparatively simple because the motion is fairly steady. When we come to lateral and directional control the motion cannot be kept up indefinitely, and not only does measurement become difficult but the actual motion ,of the aeroplane depends on the pilot and how rapidly he moves the controls to predetermined positions. For instance, the time to bank to 45° was measured for several aeroplanes and the time recorded was found to vary in apparently identical conditions on the same aeroplane with the same, pilot by as much as 1 sec in about 3 secs. By great care a very valuable set of results was eventually obtained, which did clearly put the machines in an order of excellence, but that order was not probably the order of preference of the average pilot of these machines.

I am not sure that we shall ever be able to put down everything about this very debated question in black and White -personal preferences will always have a good ideal of weight. But we shall gradually clear up a number of uncertainties which now trouble us, and the time will come when we shall be able to say to a man, “that machine will do what you want, and it is better for that purpose than any other machine," and if he says he cannot make it do what he wants, we shall be able to say that the fault is his and not the machine's. At present we are inclined to hang our heads and go away and try to satisfy what are in many cases purely personal prejudices."

Attached Files


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#68 piecost

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Posted 29 January 2012 - 02:26

Doh, point 4; the DVII can achieve a similar turn rate (at a higher radius) by flying 15mph faster!
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#69 hq_Jorri

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Posted 29 January 2012 - 10:48

Mig77 tested the Sopwith Camel in rof to 40deg/s @ 120km/h with a full tank and at ground level.

He also tested the D.VIIF (before it was updated) to turn 36deg/s @ 110km/h at the same settings.

These were turns to the right.
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#70 Panthera

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Posted 29 January 2012 - 12:06

Nice charts piecost, many thanks for that :)

It looks like 777 is using too low a CLmax figure for the aircraft fitted with the Goettingen 298 airfoil, whilst the Pfalz D.III has a more realistic CLmax.

However a possible reason for the Camel's rather unrealistic turning prowess ingame is very likely linked to its' unrealistically high speed of 190 km/h at SL, indicating that 777 has modelled the aircraft with either too much power available or too little drag.

As for the difference in CLmax between the DVII & DVIIF, when pulling propeller aircraft recieve an increase in power/thrust the calculated CLmax of the wing rises as air is propelled faster over the wings. One will see this when comparing the calculated CLmax of propeller aircraft with the engine on or off.

Also reading up on the effects of stagger etc in biplanes, there seems to be an advantage in efficiency when the lower wing is smaller than the top one, so I believe this is another advantage added to the Fokker's list.


I did make a rather funny discovery though when comparing the speeds of the aircraft we have ingame with the speeds of the same aircraft as reported in the history books (Note: the history books usually aren't 100% right themselves ofcourse):


Official figures vs ROF

Sopwith Camel: 185 km/h vs 190 km/h
Sopwith Triplane: 185 km/h vs 185 km/h
SE5a: 222 km/h vs 222 km/h
SPAD XIII: 218 km/h vs 220 km/h
_________________________________________

Fokker Dr.1: 185 km/h vs 178 km/h
Fokker DVIIF: 200 km/h vs 195 km/h
Albatros D.Va: 187 km/h vs 170 km/h
Albatros D.III: 180 km/h vs 170 km/h


Looking at the figures above it seems like German aircraft are given a pretty bad rep in this game for some reason, where'as British & French aircraft are closer to the numbers in the books, and often better.
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#71 Tom-Cundall

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Posted 29 January 2012 - 12:13

Official figures vs ROF

Sopwith Camel: 185 km/h vs 190 km/h
Sopwith Triplane: 185 km/h vs 185 km/h
SE5a: 222 km/h vs 222 km/h
SPAD XIII: 218 km/h vs 220 km/h
_________________________________________

Fokker Dr.1: 185 km/h vs 178 km/h
Fokker DVIIF: 200 km/h vs 195 km/h
Albatros D.Va: 187 km/h vs 170 km/h
Albatros D.III: 180 km/h vs 170 km/h


Looking at the figures above it seems like German aircraft are given a pretty bad rep in this game for some reason, where'as British & French aircraft are closer to the numbers in the books, and often better.

Would you like to list your sources?

'History books' doesn't count if you want to be listened to or taken seriously.

Also sorry for the delay in replying your suggestion that the D.IIIa was correct while the D.VIIF is wrong stunned me for a bit - I had to lift my jaw back off the floor.

Then your last bit of Wingerian paranoia about 'bad rep' for German planes then removed any remaining credibility.
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#72 piecost

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Posted 29 January 2012 - 12:44

Jorri, I assume that Mig77s tests were are sustained turns.

The Camel test point coincides well with the Pfalz DIIIa curve and the Camel curve underneath it. So perhaps this is the slowest sustained turn, where the sustained turn and instantaneous turns are coincident (i.e. the slowest sustained turn, limited by stalling)

The Fokker DVIIf turn test is well above my curve suggesting than my estimated CLmax is 15% too low.

My values of CLmax were for the engine idling, the maximum lift is significantly increased with power.
The turn rate graph is for maximum power, so the curves should probably be a bit higher.

I have not shown sustained turns as I did not successfully measure it.
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#73 Panthera

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Posted 29 January 2012 - 13:32

Having a bad day again Tom Cundall ? Seriously, drink your coffee next time before responding in such a rash manner.

Also sorry for the delay in replying your suggestion that the D.IIIa was correct while the D.VIIF is wrong stunned me for a bit - I had to lift my jaw back off the floor.

Why is that? The Pfalz D.IIIa featured a very high camber airfoil, and I mean very high, with a correspondingly high CLmax.

Image

The Albatros D.III & D.V fighters also feature a very high camber airfoil btw, such as the Goettingen 173 etc.

So with the above in mind how is it I am so wrong in assuming that the Pfalz's CLmax is more correctly modelled ingame atm than the Fokker DVIIF's ? I'd like you to enlighten me on that part. Just saying *Your wrong!* over and over again doesn't stand as proof or evidence of anything Cundall, other than you disliking what is being suggested ofcourse.

Then your last bit of Wingerian paranoia about 'bad rep' for German planes then removed any remaining credibility.

Wingerian ? Seems it's easy to get on your bad side Cundall, and no I'm not having any form of paranoia here, I just find it interesting that British & French aircraft ingame are so much closer to their often quoted values than their German counterparts. Apparently you don't, which is fine, but it doesn't ruin my credibility in any way.

Also you can't honestly say that you don't find it just a little strange that the Albatros D.Va is 17 km/h too slow ingame atm ? (170 vs 187 km/h)
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#74 MiG-77

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Posted 29 January 2012 - 13:51

Jorri, I assume that Mig77s tests were are sustained turns.

Yes, those were sustained turns (couple of full circles already turned before I even started timing). Planes could turn slower speed aswell but they were not fastest way to get around 360deg (also I only tested speeds with 10km/h interwalls. IE from 110km/h -> 120km/h -> 130km/h, not 115km/h or 125km/h. So "optimal" also can be anything between those "full tens").
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#75 Panthera

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Posted 29 January 2012 - 13:52

The Albatross D.Va's wing profile:
Image
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#76 Tom-Cundall

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Posted 29 January 2012 - 14:14

What are your sources for those speeds? What 'history books'?

Stop evading the question.

Yes the Albs and the D.IIIa are too slow and the Camel and Dr.1 too fast.

The D.IIIa is a very odd (unplausible ATM) FM using it as an example to prove a point is an illustration that you haven't played the sim much.
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#77 Panthera

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Posted 29 January 2012 - 14:15

According to the Airfoil Investigation Database the airfoils used on these aircraft compared as follows in terms of CLmax:

Goettingen 298 CLmax = 1.54
Goettingen 173 CLmax = 1.61
Pfalz 11 CLmax = 1.53
RAF 15 CLmax = 1.05

One must remember though that the thinner airfoils suffer from som nasty stalling characteristics in terms of a sudden seperation of the boundary layer at a rather low critical AoA.

No data on the site regarding the RAF 14 sadly. Also the above figures aren't to be taken as the final word on the matter, esp. since we aren't sure how the results were achieved, may it be from use of advanced computer software or actual windtunnel testing.
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#78 Panthera

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Posted 29 January 2012 - 14:33

What are your sources for those speeds? What 'history books'?

Stop evading the question.

Evading ? Only one evading the real question here is yourself.

Anyway as for my sources on the speeds, NASA's Quest for performance article is one of them, which lists all of its' sources as-well. "German Combat Planes" by Ray Wagner is a good reference for me as-well.

Yes the Albs and the D.IIIa are too slow and the Camel and Dr.1 too fast.

What is your source that the Dr.1 is too fast ? It was apparently capable of 165 km/h at 4000 m, which would correspond well with a 180 to 185 km/h top speed at SL. Also Mikael Carlson's faithful reproduction cruises at 160 km/h, and he mentions it to be much less draggy of an aircraft than any of the conventionally rigged WW1 aircraft he has flown.

In short: Evidence very much seems to suggest that with the 110 hp UR.IIa the Dr.1 was capable of a 180 to 185 km/h top speed at SL.

The D.IIIa is a very odd (unplausible ATM) FM using it as an example to prove a point is an illustration that you haven't played the sim much.

What ? Sorry but that's simply nonesense. The D.III turns very well ingame, which I have duly noted and not found to be at odds with how one would percieve it to fly based on its' design. Using an airfoil design with a CLmax higher than 1.6 on an aircraft with a low wing loading and you'd expect a pretty tight turning crate - which is what we got ingame as far as I can tell.

Only odd thing about the D.IIIa ingame is its' extremely mild stall, I'd expect a much more violent depature considering the design of the airfoil. So that is one thing which needs to be looked into, but then again that goes for quite a few aircraft. Currently only the SPAD fighters really seem to suffer from their thin airfoils, where'as other thin winged aircraft fly almost as if they have leading edge slats installed.
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#79 ImPeRaToR

ImPeRaToR
  • Posts: 7902

Posted 29 January 2012 - 15:00

where'as other thin winged aircraft fly almost as if they have leading edge slats installed.

Have you flown the Dolphin, D.XII or Camel with high fuel?
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#80 Panthera

Panthera
  • Posts: 462

Posted 29 January 2012 - 15:58

where'as other thin winged aircraft fly almost as if they have leading edge slats installed.

Have you flown the Dolphin, D.XII or Camel with high fuel?

Yes I have. In that configuration they are not part of the problem however, aircraft such as the Albatross & Pfalz D.III howecer seem too forgiving, they can be flown too easily near the stall IMO.

As for the Pfalz D.XII, that thing has a vicious and irrecoverable flat spin ingame, which perhaps needs to be looked into, not so much in terms of the fact that it stalls easily, but more the fact that it can't be recovered in a spin.
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