Holtzauge Posted May 3, 2016 Author Posted May 3, 2016 Holtzauge, any news from your contact regarding (no) wing twist on the Yak-1? Unfortunately I did not get any new info on the Yak-1. However, it seems the Yak-18Т wing also utilizes the Clark YH with 14,5% root and at the 9,3% tip. Apparently this aircraft has a Clmax of 1.32 according to "Practical aerodynamics" by author Bekhtir. He also thought that the Yak-18T had wing twist but did not have any details on the angles. So not much new info to go on really. Given the stuff that has been uncovered so far in this thread and that the Spitfire Clmax is cited at 1.36 and the Me-109 at 1.4 typically one can’t really say 1.39 is wrong for the Yak-1 without more evidence I think. However, what still stays strange IMHO is that the Yak-1 comes so much more closer to Its 2-D Clmax potential as compared to the Fw-190 in BoS…… Makes you wonder how the other planes in BoS are doing? Seeing you did such a good job on measuring the BoS Yak-1 and Fw-190 JtD, what would it take to get you to do the same for the Me-109?
JtD Posted May 3, 2016 Posted May 3, 2016 Thanks for the info on the Yak-18, sound reasonable, again - 1.32, 1.36, 1.4 - proper ranking and proper range. I don't think I want to/can spend a good part of another day in front of the screen right now, lots of things to do plus spring is here and it finally looks as if it was going to stay. But I'm curious about this, too, so I'll probably do it in the not too far future. I'm mostly interested in the La, because they also use the 23000 series airfoil, albeit with leading edge slats. Which in turn might makes the other LE slats plane, the 109, pretty interesting. I'm also curious about how similar LaGG/La and the two 109's are.
303_Kwiatek Posted May 3, 2016 Posted May 3, 2016 (edited) Regaring Clmax and cAoA interesting is that Yak-1 and Lagg3 got 18 deg cAoA ( suprisly high), for comparison Fw 190 A-3 - 15.5 deg cAoA, Mig3 ( with slats) - 17.3 deg and P-40 only 14 deg cAoA. If Yak-1 and Lagg-3 got such high cAoA it could also got high Clmax. I wonder also P-40 cause it got terrible sustained turn rate in BOS. From Russian test sustained turn rate P-40 E got 19 sec. at 1000m which should be little better then 109 F-4 or G-2. Looks for me that in BOS wing polar of P-40 could be wrong? Edited May 3, 2016 by 303_Kwiatek
Kurfurst Posted May 5, 2016 Posted May 5, 2016 Regaring Clmax and cAoA interesting is that Yak-1 and Lagg3 got 18 deg cAoA ( suprisly high), for comparison Fw 190 A-3 - 15.5 deg cAoA, Mig3 ( with slats) - 17.3 deg and P-40 only 14 deg cAoA. If Yak-1 and Lagg-3 got such high cAoA it could also got high Clmax. I wonder also P-40 cause it got terrible sustained turn rate in BOS. From Russian test sustained turn rate P-40 E got 19 sec. at 1000m which should be little better then 109 F-4 or G-2. Looks for me that in BOS wing polar of P-40 could be wrong? While we are at it, the listed turn times of the 109G also seem to be wrong, listed as cc 22 sec. Russians themselves got 20/21,5 sec from the plane they have captured at Stalingrad. See. http://kurfurst.org/Tactical_trials/109G_Soviet/109G_NIIVVS_1944.pdf
303_Kwiatek Posted May 5, 2016 Posted May 5, 2016 22 sec was for version with wing gunpods. Normal vesion in Russian data is 20-21 sec
Crump Posted July 31, 2016 Posted July 31, 2016 Pretty much what I'd be expecting, too. 1.6 - 0.2 = 1.4 --- Holtzauge, any news from your contact regarding (no) wing twist on the Yak-1? I am sorry JtD. I missed this because I pretty much ignore you. Focke Wulf figure for a CLmax of 1.58 for the airplane gives good agreement with all the 2D data and the fact our full sized airplane will not attain the CLmax of 1.75. Interestingly enough, the NACA concludes the change is ~.2 on the CLmax. 1.75-1.58 = .17 change coefficient of lift for the Focke Wulf. That agrees with the NACA results. 1
JtD Posted July 31, 2016 Posted July 31, 2016 Are you aware that the 0.2 NACA refers to here are the difference between a model aircraft in the 19 foot tunnel and a real aircraft in the full scale tunnel and have nothing to do with a 2D - 3D relation? If you were to look at the data actually given, you'd see that the F4U they tested in the full scale tunnel is using a 23018 root - 23009 tip airfoil and is obtaining a Clmax of about 1.15 - 1.25. Which is 0.4 less than what was measured for the airfoils. Likewise, the F6F they tested, using 23016 - 23009 achieved less than 1.3 in service condition and less than 1.4 after being modified. There must be special German laws that alter physics so that the Fw190 gets 1.58, pretty much like we in game have special Soviet laws for the Yak.
Crump Posted July 31, 2016 Posted July 31, 2016 The F6F-4 CLmax of 1.4 is the accelerated flight CLmax which is a completely different animal as airspeed measurement becomes very unreliable in accelerated flight! It is not the same topic. Once more, the definition of a stall between the NACA and RLM is not the same. In the NACA, the stall is the point the aircraft begins to exhibit adverse behavior and control becomes degraded. In the RLM, the stall is the point the wing breaks and no longer flies. That is why the FW-190's Landing Speed (1.1Vs) matches the Clean Configuration Stall Speed!! You can see that on the lift coefficient graphs provided by the NACA that they got 1.5 easily in the power off condition. He attempted to control the aircraft and you can see his input just before the stall when the longitudinal buffet kicks. I think he could have gotten higher if he would have not put the angular acceleration on the wing. For the power on, the ailerons and rudder where fixed and the pilot did not attempt to control the airplane thru the stall. Here we get a power on CLmax of over 2.0!! Power on will always be higher than power off CLmax due to propeller effects. You have upwash from the ascending blade and boundary layer gets some energy from the thrust axis. Now that is all clean configuration! He is a comparison of experimental data on wing design vs calculated data. The wing using the NACA 23015 root and NACA 23009 wingtip airfoil like the FW-190 and the F6F Hellcat has a CLmax of 1.71 determined experimentally and 1.7 calculated. That Focke Wulf would use 1.58 as the designs CLmax is unremarkable for that airfoil selection and well within normal range of what would be expected. It is just plain old physics. 1.4 is far below what you should see for the clean configuration CLmax for that airfoil selection. It would represent an impaired aircraft with lots of surface contamination, wing racks, poorly construction, or any number of issues that are NOT representative of a typical fighter variant. The other way that value comes into play is if you do not apply any Position Error Correction to the raw indicated airspeed. That is fine if you are just going to fly the airplane. It is invalid though for comparative performance. As for the practical side of relative performance and your game.... Focke Wulf tells us the CLmax. If you do an analysis using standard aircraft performance math using their CLmax.... It works perfectly and the aircraft fits all of its physical and anecdotal evidence. It still is not a great sustained turner and does not become a UFO. It simply balances the aircraft better.
JtD Posted July 31, 2016 Posted July 31, 2016 The F6F-4 CLmax of 1.4 is the accelerated flight CLmax which is a completely different animal as airspeed measurement becomes very unreliable in accelerated flight! It is not the same topic. Absolutely. And if NACA did indeed measure accelerated stall in their wind tunnel, they'd have been years ahead of everybody else. As it is, they didn't, and their air speed measurements are far more accurate than the ones taken in some flight tests. As usual, you don't have a clue what I'm talking about. If you so much like to put words in other peoples mouths, you can save yourself a lot of time if you just argue with a mirror. 1
Crump Posted July 31, 2016 Posted July 31, 2016 JtD.... They included the Coefficient of Lift information in the stall testing.... That is the charts I posted. Read them and use your brain. You are a smart guy and frankly I am impressed that you are able to do some of the science without ever having sat in a classroom. That is a good trait. Being obstinate and stubborn just to be right is not a good trait. You are the one who claimed the NACA 23015.NACA 23009 was limited to a CLmax of 1.4 in the F6F. That is just not true in any sense of the word and it is not my fault you did not read the report or understand the information.
JtD Posted July 31, 2016 Posted July 31, 2016 Dude, I'm quoting full scale wind tunnel figures published by NACA. Read them up and correct NACA, not me. Same way, flight test by NACA I quote "the maximum lift coefficient in the gliding condition varied between 1.35 and 1.45" which is just slightly more than what NACA tested in the wind tunnel and easily explained by the different test methods. Likewise, Focke Wulf tested the Fw190 CLmax in the 1.3 range in the wind tunnel. Plus, Focke Wulf explicitly states they are using the 1.58 for the determination of the landing speed in the landing configuration. Your 1.58 clean fantasy was entertaining to some point, but it's just a fantasy and your spamming is just annoying by now.
Crump Posted July 31, 2016 Posted July 31, 2016 Dude, I'm quoting full scale wind tunnel figures published by NACA. Read them up and correct NACA, not me. Dude.... I just posted the report you quoted INCORRECTLY along with all the NACA wind tunnel and calculated data.... The NACA 230015/NACA23009 airfoil combination in a wing design simply produces much higher coefficients of lift than 1.4. End of Story. Here is the report, btw. F6F3 Stall.pdf Did you or did you not say: Likewise, the F6F they tested, using 23016 - 23009 achieved less than 1.3 in service condition and less than 1.4 after being modified. I am sorry, but the NACA report does not support such a low CLmax in the F6F-3 for an unmodified aircraft. You pulled values out of thin air. I posted verifiable facts and data compiled by the NACA on the F6F. Nor does it change the fact Focke Wulf GmbH used 1.58 as the CLmax for the clean wing design. That value is well within the limits of what can be expected from the NACA 230015/NACA23009 airfoil selection. The data fits in every way including the fact Focke Wulf used a Clmax of 1.58 to determine both Landing Speed (1.1Vs) and clean configuration stall speed (Vs). Landing Speed is NOT stall speed. It is Landing Speed and typically 1.1 times Stall Speed in the landing configuration. That gives EXCELLENT agreement with the RAE results of Clean Configuration Stall speed of 110mph IAS exactly matching Touchdown Speed of 110mph IAS. Stall speed in the Landing Configuration was found to be 105mph IAS. RAW airspeed measurements puts Touchdown Speed at 1.1Vs according to the RAE measurement exactly matching our 1.1Vs requirement within the realm of significant digits. You find the same results on every test that shows stall speeds. The second RAE test also shows 1.1Vs for the Landing Speed exactly matching the Focke Wulf Landing chart used by the pilot to determine his Landing Speed. That is kind of a wrap, JtD and end of discussion. It is that simple and is the only explanation that fits all science, design convention, airfoil selection, and the reality of airspeed measurement. Once more, in the mechanics of aircraft performance math you use the 2D data of the root airfoil. Using anything else will not produce the correct results out of the math formula. End of Story.
Crump Posted July 31, 2016 Posted July 31, 2016 Read the reports, contact NACA. That IS the NACA data on the NACA23015/NACA23009 wing design AND the F6F-3 data you inaccurately quoted: It would probably help if you had a little practical experience. You are stuck on that "Landing Speed" being the stall point in clean configuration. That is simply useless information to a pilot. In thousands of hours at the controls and thousands of landing, I have never ONCE looked at my airspeed after arriving over the numbers or until after the wheels have touched down and the aircraft has slowed down under control. The last time a pilot checks airspeed is about 1000 feet from where the wheels touch down on most aircraft of any size, weight, and power. The fact the FW-190 POH and the RAE data backs it up the conclusion that the Landing Speed chart tells us that is the Approach Speed. It is 1.1Vs and the speed we need to be at over the numbers. If it was our stall speed, we would not land but rather tumble down the runway in a huge fireball. In other words, Landing Speed simply cannot be Stall Speed in the Landing configuration. We can confirm that by looking in any aerodynamic textbook to find the definition of Landing Speed.
JtD Posted July 31, 2016 Posted July 31, 2016 I quoted wind tunnel data, not flight test data. I've said that already. If you don't get it, don't blame me.
Crump Posted July 31, 2016 Posted July 31, 2016 BTW, for the readers... Both the F6F-3 Hellcat and FW-190 used the airfoil combination of the NACA 230015 root airfoil and NACA 23009.
Crump Posted July 31, 2016 Posted July 31, 2016 I quoted wind tunnel data, not flight test data. I've said that already. If you don't get it, don't blame me. Mmmm. You quoted 1.4 as the CLmax of the F6F3 without an understanding of the conditions that value was derived. That does NOT limit the wing design to that 1.4 as CLmax is based upon Reynolds Number. That is a fancy way of saying surface condition and atmospheric effects. And the significance of that 1.4 value is what? Nothing outside of you pulling some baloney out of thin air. Put the NACA 23015/NACA 23009 at sea level on a standard day traveling at an FW-190 stall speed, and you can easily get a CLmax of 1.58 out of the airfoil selection. In fact, 1.4 or less is simply not viable unless you wish to represent an impaired aircraft.
Crump Posted August 1, 2016 Posted August 1, 2016 Are you aware that the 0.2 NACA refers to here are the difference between a model aircraft in the 19 foot tunnel and a real aircraft in the full scale tunnel and have nothing to do with a 2D - 3D relation? It compares all the results from the 2D data thru the finished aircraft. The top graphs show the 2D data. The models give good agreement with the 2D data and the entire aircraft can be as much as .2 reduction depending on surface condition.
JtD Posted August 1, 2016 Posted August 1, 2016 I take this as a no. I'd recommend to read again, but I know you'll ignore that. So I quote "...the airplane in service condition had a maximum lift coefficient more than 0.2 lower than that of the model..." Read up or don't.
Crump Posted August 1, 2016 Posted August 1, 2016 I take this as a no. I'd recommend to read again, but I know you'll ignore that. So I quote "...the airplane in service condition had a maximum lift coefficient more than 0.2 lower than that of the model..." Read up or don't. Wow...Maybe you should read it again and drop the attitude. After all....you are the one who made the silly claim about the Hellcat because you did not read the information!!! Let me spell it out.... 2D data gives good agreement with Models means 2D data = Models. That is what the top of the page comparison of 2D data to wind tunnel test results using a model tells us. Model to full size aircraft can be as much as .2 off the CLmax depending on the "fit and finish" of the full size aircraft. If careful attention is not paid to the full size aircraft it will not give as good agreement as 2D data to model. So, in other words, the full size aircraft is not necessarily going to be any different than the 2D data as long as the design team prepares the full size aircraft accordingly. That means ensuring it is properly constructed and has a normal aircraft finish. If the finish is not done properly and the aircraft is not constructed properly then it will not agree. That is why we still use models today!!
unreasonable Posted August 1, 2016 Posted August 1, 2016 JtD your mailbox is full. You must realize by now that this is hopeless, you cannot ever have the last word with such. Go chase some Aryan maidens in the sun! 1
JtD Posted August 1, 2016 Posted August 1, 2016 JtD your mailbox is full. You must realize by now that this is hopeless, you cannot ever have the last word with such. Go chase some Aryan maidens in the sun! Yeah, I was going to post something along the lines of "whatever". Pity the topic was killed in the process, it is still containing some open points.
Crump Posted August 6, 2016 Posted August 6, 2016 Model to full size aircraft can be as much as .2 off the CLmax depending on the "fit and finish" of the full size aircraft. If careful attention is not paid to the full size aircraft it will not give as good agreement as 2D data to model. So, in other words, the full size aircraft is not necessarily going to be any different than the 2D data as long as the design team prepares the full size aircraft accordingly. That means ensuring it is properly constructed and has a normal aircraft finish. If the finish is not done properly and the aircraft is not constructed properly then it will not agree. That is why we still use models today!! That is the main take away of the NACA data. 2D data + Induced angle of Attack equals the full sized aircraft's angle of attack. That is math formula used today and why we use the 2D data of the root airfoil as valid data for determining the full sized aircraft's CLmax. We still use models today because they give good agreement with both the 2D data and the full sized aircraft. The design team just has to be careful and the NACA data shows them what to look for the full sized aircraft polar is impaired!!! Bottom line, if the polar is impaired, then there is something WRONG! LOL.
Crump Posted August 13, 2016 Posted August 13, 2016 There must be special German laws that alter physics so that the Fw190 gets 1.58, pretty much like we in game have special Soviet laws for the Yak. http://forum.il2sturmovik.com/topic/21732-whats-your-opinion-new-fw-fm/?p=376053 http://forum.il2sturmovik.com/topic/21732-whats-your-opinion-new-fw-fm/?p=376176 http://forum.il2sturmovik.com/topic/21732-whats-your-opinion-new-fw-fm/?p=376178 http://forum.il2sturmovik.com/topic/21732-whats-your-opinion-new-fw-fm/?p=376182 Crumpp says: So in conclusion we can believe that Kurt Tanks clean wing Clmax of 1.58 is in good agreement with other tested data on the NACA 23015/23009 airfoil selection at a Reynolds number of 6.1 x 10-6 stall speed vicinity of the design. It represents the power off stall CLmax of the design straight from the design teams own data. That airfoil series was selected for its high CLmax like every other engineer who picked it. Or we can believe that physics was altered on the European side of the world and Focke Wulf was just an extremely incompetent designer who could not even get in the ballpark of the clean wing Clmax even with 60 degrees of 35% wing coverage Split Flaps deployed.... It is up to the reader to decide! It is a lot of data, digest it slowly JtD!
JtD Posted August 13, 2016 Posted August 13, 2016 (edited) I've read that like 10 years ago. Truth still is that a model isn't the full aircraft, and the full aircraft was tested by NACA at ~1.3 in the wind tunnel and ~1.4 in flight tests. So... whateverTry fishing for someone else's attention. Edited August 13, 2016 by JtD 1
Crump Posted August 13, 2016 Posted August 13, 2016 Truth still is that a model isn't the full aircraft, and the full aircraft was tested by NACA at ~1.3 in the wind tunnel and ~1.4 in flight tests. So... No it is a actually a flight test....and a model comparison...and they give good agreement at the same Reynolds number with the 2D data. All is well and as it should be.... F6F3 Stall.pdf But anyway I just want to see if you were man enough to admit the truth or if you would continue to argue even when wrong.... From another NACA report.....
NZTyphoon Posted August 14, 2016 Posted August 14, 2016 (edited) But anyway I just want to see if you were man enough to admit the truth or if you would continue to argue even when wrong.... Pot calling Kettle...Talk about someone who NEVER admits he's wrong about anything! Funny how Crump hijacks every thread he can lay his paws on and turns it into a Crump vs everybody else stoush, just to prove that he alone is some kind of aeronautical genius, while everyone else (except those who agree with him) is, ICNSHO (In Crump's Not So Humble Opinion ), a moron.He's been doing it for years on many many forums, most of which have banned him, and he hasn't yet got the message. Edited August 14, 2016 by NZTyphoon 2
Crump Posted August 14, 2016 Posted August 14, 2016 ot calling Kettle...Talk about someone who NEVER admits he's wrong about anything! Funny how Crump hijacks every thread he can lay his paws on and turns it into a Crump vs everybody else stoush, just to prove that he alone is some kind of aeronautical genius, while everyone else (except those who agree with him) is, ICNSHO (In Crump's Not So Humble Opinion ), a moron.He's been doing it for years on many many forums, most of which have banned him, and he hasn't yet got the message. The righteous indignation of it all!!! Grrrrr........ Thank god you are here to warn the public about me and the NACA as named co conspirators against the Spitfire... <PS - airfoils are basics...not aeronautical genius stuff, LMAO!>
=EXPEND=Tripwire Posted August 14, 2016 Posted August 14, 2016 (edited) I enjoy "attempting" to read some of the charts, data and assessments that Crump and others have provided even though I don't have the ability to contribute in any meaningful way. I'm sure there are others that do too. Keep on posting Crump. Please keep the personal attacks out, as I am sick of seeing threads get locked when there was some awesome content being provided. Edited August 14, 2016 by Tripwire
NZTyphoon Posted August 14, 2016 Posted August 14, 2016 The righteous indignation of it all!!! Grrrrr........ Wry amusement actually. Thank god you are here to warn the public about me and the NACA as named co conspirators against the Spitfire... Thank God Crump got himself banned from ED and can no longer plague the developers with his cockeyed theories.
JtD Posted August 14, 2016 Posted August 14, 2016 I enjoy "attempting" to read some of the charts, data and assessments that Crump and others have provided even though I don't have the ability to contribute in any meaningful way. I'm sure there are others that do too. Keep on posting Crump. For as long as in your attempts you manage to see a difference between a perfectly smooth wooden model, without leakage through hatches, panels or fold joints, with no disturbances from gun inlets and other leading edge protrusions, and an aircraft in service condition, I'm sure you can put the data provided into the right perspective. If, however, your attempts end with you swallowing the misinformation campaign as a whole, I'd say you're better off not reading any of it. Instead, the next time you feel like filling your head with something, go to the primary sources. Takes more effort, but in the long term is much more rewarding. The NASA technical reports server is free to access for everyone, and full of interesting information from the era, with hundreds of reports available. You can use the search function at your leisure, just type in the plane type or topic you're interested in and see what it gets you. For instance, search for documents that have F6F in the title to find the flight test report. On the subject of wind tunnels, air foils, lift coefficients and so on, there's plenty. Below just a few to get you started. Summary of Measurements in Langley Full-Scale Tunnel of Maximum Lift Coefficients and Stalling Characteristics of Airplanes - The technical report 829 Summary of Measurements in Langley Full-Scale Tunnel of Maximum Lift Coefficients and Stalling Characteristics of Airplanes - Similar to technical report 829, but a bit nicer formatted. Summary of Airfoil Data - The technical report 824. Summary of Airfoil Data - Similar to technical report 824, but a bit nicer formatted. Tests in the 19-foot Pressure Tunnel of a 1/2.75-scale Model of the F4U-1 Airplane with Several Balanced Elevators, Full-span Flaps, and Droppable Gas Tank - model data Wind-Tunnel Tests of a 0.182-Scale Model of an F4U-1 Airplane with External Stores - a bit on stores drag Summary of Data Relating to the Effects of Wing Machine-gun and Cannon Installations on the Aerodynamic Characteristics of Airplanes - some figures for reduced lift and increased drag caused by a variety of gun installations Effect of Mach and Reynolds Numbers on the Maximum Lift Coefficient Obtainable in Gradual and Abrupt Stalls of a Pursuit Airplane Equipped with a Low-Drag Wing - P-63 flight tests Comparative Flight and Full-Scale Wind-Tunnel Measurements of the Maximum Lift of an Airplane - 1938, but used as a general reference in many later reports Wind-tunnel investigation of NACA 23012, 23021, and 23030 airfoils with various sizes of split flap - wind tunnel/airfoil data Flow Observations with Tufts and Lampblack of the Stalling of Four Typical Airfoil Sections in the NACA Variable-density Tunnel - wind tunnel/airfoil data Design charts relating to the stalling of tapered wings - wind tunnel/airfoil data Additional design charts relating to the stalling of tapered wings - wind tunnel/airfoil data Effects of Mach Number and Reynolds Number on the Maximum Lift Coefficient of a Wing of NACA 230-series Airfoil Sections - wind tunnel/airfoil data Airfoil Section Characteristics as Affected by Variations of the Reynolds Number - wind tunnel/airfoil data Wind-tunnel investigation of NACA 23012 airfoil with various arrangements of slotted flaps - wind tunnel/airfoil data Wind-Tunnel Investigation of an NACA 23012 Airfoil with Various Arrangements of Slotted Flaps - wind tunnel/airfoil data The experimental and calculated characteristics of 22 tapered wings - wind tunnel/airfoil data Maximum lift coefficients of airplanes based on sum of wing and tail areas - simple maths Study of Turning Performance of a Fighter-Type Airplane Particularly as Affected by Flaps and Increased Supercharging, Special Report - a little bit on turning performance calculation, interesting because it includes flaps Summary of Lateral-control Research - Report 868 - basics of rolling characteristics and performance. Summary of Lateral-control Research - Similar to report 868, but a bit nicer formatted. Of course, there's a load more, on many subjects.
Crump Posted August 14, 2016 Posted August 14, 2016 For as long as in your attempts you manage to see a difference between a perfectly smooth wooden model, without leakage through hatches, panels or fold joints, with no disturbances from gun inlets and other leading edge protrusions, and an aircraft in service condition, I'm sure you can put the data provided into the right perspective. If, however, your attempts end with you swallowing the misinformation campaign as a whole, I'd say you're better off not reading any of it. Instead, the next time you feel like filling your head with something, go to the primary sources. Takes more effort, but in the long term is much more rewarding. The NASA technical reports server is free to access for everyone, and full of interesting information from the era, with hundreds of reports available. You can use the search function at your leisure, just type in the plane type or topic you're interested in and see what it gets you. For instance, search for documents that have F6F in the title to find the flight test report. On the subject of wind tunnels, air foils, lift coefficients and so on, there's plenty. Below just a few to get you started. Summary of Measurements in Langley Full-Scale Tunnel of Maximum Lift Coefficients and Stalling Characteristics of Airplanes - The technical report 829 Summary of Measurements in Langley Full-Scale Tunnel of Maximum Lift Coefficients and Stalling Characteristics of Airplanes - Similar to technical report 829, but a bit nicer formatted. Summary of Airfoil Data - The technical report 824. Summary of Airfoil Data - Similar to technical report 824, but a bit nicer formatted. Tests in the 19-foot Pressure Tunnel of a 1/2.75-scale Model of the F4U-1 Airplane with Several Balanced Elevators, Full-span Flaps, and Droppable Gas Tank - model data Wind-Tunnel Tests of a 0.182-Scale Model of an F4U-1 Airplane with External Stores - a bit on stores drag Summary of Data Relating to the Effects of Wing Machine-gun and Cannon Installations on the Aerodynamic Characteristics of Airplanes - some figures for reduced lift and increased drag caused by a variety of gun installations Effect of Mach and Reynolds Numbers on the Maximum Lift Coefficient Obtainable in Gradual and Abrupt Stalls of a Pursuit Airplane Equipped with a Low-Drag Wing - P-63 flight tests Comparative Flight and Full-Scale Wind-Tunnel Measurements of the Maximum Lift of an Airplane - 1938, but used as a general reference in many later reports Wind-tunnel investigation of NACA 23012, 23021, and 23030 airfoils with various sizes of split flap - wind tunnel/airfoil data Flow Observations with Tufts and Lampblack of the Stalling of Four Typical Airfoil Sections in the NACA Variable-density Tunnel - wind tunnel/airfoil data Design charts relating to the stalling of tapered wings - wind tunnel/airfoil data Additional design charts relating to the stalling of tapered wings - wind tunnel/airfoil data Effects of Mach Number and Reynolds Number on the Maximum Lift Coefficient of a Wing of NACA 230-series Airfoil Sections - wind tunnel/airfoil data Airfoil Section Characteristics as Affected by Variations of the Reynolds Number - wind tunnel/airfoil data Wind-tunnel investigation of NACA 23012 airfoil with various arrangements of slotted flaps - wind tunnel/airfoil data Wind-Tunnel Investigation of an NACA 23012 Airfoil with Various Arrangements of Slotted Flaps - wind tunnel/airfoil data The experimental and calculated characteristics of 22 tapered wings - wind tunnel/airfoil data Maximum lift coefficients of airplanes based on sum of wing and tail areas - simple maths Study of Turning Performance of a Fighter-Type Airplane Particularly as Affected by Flaps and Increased Supercharging, Special Report - a little bit on turning performance calculation, interesting because it includes flaps Summary of Lateral-control Research - Report 868 - basics of rolling characteristics and performance. Summary of Lateral-control Research - Similar to report 868, but a bit nicer formatted. Of course, there's a load more, on many subjects. Ha ha ha ah!! The first four reports are the referenced in this thread!! So you take the information with the conclusions I posted from the NACA and now list the same sources without any conclusion leaving the reader to believe it supports your wrong conclusion from earlier in the thread. Isn't that a strawman argument? We post something that is correct in place of our your original statement which was not correct.... Specifically being that the CLmax listed byFocke Wulf for the clean wing could not possibly be the clean wing CLmax according to you? Crumpp says: So in conclusion we can believe that Kurt Tanks clean wing Clmax of 1.58 is in good agreement with other tested data on the NACA 23015/23009 airfoil selection at a Reynolds number of 6.1 x 10-6 stall speed vicinity of the design. It represents the power off stall CLmax of the design straight from the design teams own data. That airfoil series was selected for its high CLmax like every other engineer who picked it. Or we can believe that physics was altered on the European side of the world and Focke Wulf was just an extremely incompetent designer who could not even get in the ballpark of the clean wing Clmax even with 60 degrees of 35% wing coverage Split Flaps deployed.... It is up to the reader to decide! Now I supposed to repost the information, link the report so is shows how stupid an stubborn you are being just to appear correct when you are simply wrong. Man up JtD.... Maybe learn about Reynolds Number?????
unreasonable Posted August 15, 2016 Posted August 15, 2016 As a layman, "discussions" like this often come down to: 1) Which story seems to be most consistent with the evidence? And given a layman's limitations in judging this: 2) Which "authority" is more credible? On the first, that a service condition aircraft has a lower CLmax than a smooth wooden model, full size or not, seems to be the clear conclusion, expressed in plain English, from the reports. On the second, AFAIK Crump is a professional pilot who has done some aeronautical courses. JtD is an academically trained, professional engineer who likes to simulate aircraft on PC as a hobby. When Crump flies, his passengers or cargo depend on his practical flying skills. When JtD carries out his safety studies, future citizens lives depend on his engineering competence. Suppose you got in a taxi and wanted to know the practicalities of driving it compared to your normal motor: clearly asking the cabbie would be a good idea. But suppose you wanted to know why the engine had some specific characteristics? You would ask the engineers who designed and built it. So let the reader decide who is being "stupid an stubborn".
MiloMorai Posted August 15, 2016 Posted August 15, 2016 A college professor told our class at the beginning of the term that all that book learning theory is useless until you have practical experience because reality doesn't always follow theory. We all rolled our eyes but he was so right as we all found out when we began working.
Crump Posted August 15, 2016 Posted August 15, 2016 OMG....JTD is not an aeronautical engineer. On the second, AFAIK Crump is a professional pilot who has done some aeronautical courses.. That would be correct....some aeronautical courses are in fact required to get an MSAS, lol....
unreasonable Posted August 15, 2016 Posted August 15, 2016 OMG....JTD is not an aeronautical engineer. That would be correct....some aeronautical courses are in fact required to get an MSAS, lol.... No, but he is a qualified engineer, which you are not, so it is hardly surprising that he has a grasp of the science. I think you had better just accept that there are people here who are as intelligent, knowledgeable or qualified as you, or more so, and when they disagree with you is not because they are "stupid an stubborn". By all means make your case, then leave it at that. 4
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