Crumpp

Removing large chunks of drag producing metal sticking out on both sides will help improve speed! Honestly, I am not sure what they were thinking with the original exhaust design outside of noise abatement.

The 1900PS based engine..... :doh: Got it. Thanks again Yo-Yo!

Here is the Mark I with NACA ejector stacks.

Excellent agreement....but is it a fighter variant engine?

To further illustrate the point, I have included the Lycoming O-360 Operators Manual. The connection to the German engines is the fact is it not unusual for a manufacturer to make a single engine and tune that basic engine for different applications. Junkers certainly did this for the Jumo 213 series. The engines will created different amounts of power based on that specific application. In the case of the O-360 we see a 16% power variation out of the same basic engine. The Power variation we are seeing in the Jumo 213 charts is ~4.7%.

I agree, the chart does not match the table below. [/url] While this chart does match: http://www.wwiiaircraftperformance.org/fw190/Jumo_213A_power_graph.jpg However, allow me to explain the reason why I used the power chart previously posted. During the restoration of White 1, we did not start out with a good core engine to rebuild. We proceeded in the beginning of the project with the understanding we would have to resurrect the BMW801D2. That meant buying up wrecked motors in order to acquire examples of the parts we would have to reproduce. We had quite a few wrecked BMW801D2's. When we started to disassemble the engines we began to notice details between the various wrecks were not always the same. Different magneto's, ignition harness some where even pressurized, plugs, and even different pistons. Puzzling but not unexplained. Lycoming for example makes numerous models of the O-360 and not all of them are created equal. The engine is tuned and set up for the specific installation/application based on the different missions the aircraft is expected to perform. In fact, some of this was reflected in the BMW801D2 Ersatzteilliste. Digging through the archives at the Smithsonian, we came across this report: When you get ready to make an FW-190F8, I will give you a copy of the report. It has a nice matrix of what was interchangeble with what. It was done to educate the Luftwaffe supply chain that there were 6 different BMW801D2's that were designed to go into different radial engined FW-190 variants. We finally found an overhaulable core in the form of a BMW801G2 engine. Theoretically, the same engine as the BMW801D2 but set up for bomber installation. All we thought it was missing was the synchronization gear. It even had the housing for it on the block. We were wrong and ended up having to resurrect pistons, magnetos, and other peripherals. You can see that the Jumo 213 series also had various set ups and was tuned for the installation and mission it was expected to perform. The Jumo213A1 that was installed in the FW-190D9 was a specifically tuned fighter engine. I came across this power graph as part of the investigation comparing the Jumo 213A1 as installed in the FW-190D9 to the DB603 series engines. As you know, the DB603 was a major contender and a favorite of Kurt Tank. That power curve is clearly labeled for a fighter engine variant as found in the FW-190D9. That curve matches this power chart. The clear connection to the fighter engine variant is why I use it. Just food for thought.

Yes, please fix that! It should be at sea level ~2250 hp with the worlds lowest 1st gear FTH of ~800 meters. Any idea Yo-Yo why Junkers did that?

Who said that? The purpose of running the math is to let you know if the performance is plausible. When it does not agree, it is time to start looking for answer's as to why. That reason has been found. The aircraft performance math that estimate is based on is designed to give good agreement with actual flight. Just because it is a convenient method does not mean it is not an accurate method. It has been around for ~60 years and works well. Present the evidence. Obviously Yo-Yo looks at it. If it makes sense then I am confident Yo-Yo will make the right call. His track record speaks for itself. I can tell you it would help if you knew more about the science of flight so you can pick out good data and know how to set the conditions to compare performance. Otherwise, it becomes difficult to see your point. I do not see an issue with the P-51 climb rate from what I have checked out but would extend an offer to help you compare some of the data to confirm or deny your assumption. That is the good thing about math.... it does not care about anyone's opinion.

Ahh, that is the weird instability that I sometimes experience!! Now, it is not so weird.

Never a production machine, always a new type fighter. Fixed Wing...United States Department of Defense... :music_whistling: It is a good book and is on my shelf. It does if you read the title of the graph. Climb Rate over Altitude at Climb and Combat Power. Nothing about reporting performance at Special Emergency Power. That is why curves 1, 2, and 3 include aircraft condition information. The curve you refer too has no aircraft condition information nor is it even labeled in the legend. It matches the Flugmechanik data.

The right education makes a world of difference.

You mean the racing prototype that held the world speed record for 30 years? Not exactly a production machine built for a customer. See the attached article below. And what happened with that? Bell never mass produced another fixed wing aircraft. They never got another mass production contract from the Department of Defense. Grapejam, Read the NOTES ON THE USE OF PERFORMANCE ESTIMATE The margin of error is always much smaller for level speed performance prediction vs climb performance. It is simply easier to predict level speed performance. Please read the information presented in the thread, the answers to all of your posted questions are in it and nothing new is being presented. A Yo-Yo explained, not all engines develop exhaust thrust to the same extent. It very much depends on the design of the exhaust system. On the first page of this thread, it talks about the changes made to the BMW801 series to improve the exhaust thrust of the engine. :thumbup::thumbup::thumbup::thumbup::thumbup: Yo-Yo knows what he is doing and is delivering great products. That is why I bought DCS. High Speed Feud.pdf High Speed Feud part II.pdf

This will help folks to gain an understanding of how to align some of the data found in these reports. From the Air Ministry, UK: http://www.spitfireperformance.com/spittest.html The terminology might change New Type, Experimental, Original Estimate, Provisional, Final, etc. The specific language is unique to the culture and country but the principle remains the same.

Experimental vs New type vs production...depending on the purpose of the report. It depends on who the information is for Grapejam. If is it for the company internal staff to expand its capability boundaries thru an experimental or new type design, I would agree. If the information meant for a potential buyer, as a general rule it tends to be pessimistic. That is not to say mistakes do not happen. Rules made by man do get broken. Which brings us to this: Great find...that is Focke Wulf telling us the difference in their estimates vs flight tested performance. That is a flight test of Erhöhte Notleistung. http://www.wwiiaircraftperformance.org/fw190/BMW_VB_126.pdf You have presented data but are not correctly interpreting it for different conditions of flight. That is good information. Our DCS Mustang weighs 10,066lbs clean configuration with full fuel. I do not have a weight and balance sheet for the P-51 that reflects the tail warning radar I just know there is 300lbs difference from the weight and balance sheets I have on the design.

There is actually measured data. IIRC, our pilot exert's some 34Kg/sec on the stick. That is a lot of force. Pretty much and it is a realistic one too. I think DCS modeled the effect after a NACA investigation on the maximum stick forces a pilot could exert. Part of that study is the maximum rate pilots could move the controls. That is really the thing missing in most "sims". Our pilot is quite strong as evidenced by all the broken wings.

Good post Jcomm. One the best thing's in Aviation is passing it on to the kids.

Reading the site helps to cut down on misunderstandings. None of those aircraft use butted seams AFAIK. It certainly does not appear that way on the Bf-109... http://s747.photobucket.com/user/groverpics/media/Funny/Bf109E4_spine1_zpsc968343f.jpg.html I think you are confusing the welding with the type of joint used to join the sheet metal. The Bf-109 has an overlap joint which was the most common in aviation at the time. You should probably take up the nitpicking with the website owner. I am sure he would be happy to have the information!

Which is what makes it realistic. There is a rate limit pilot's can move a control as the force on that control builds.

Which I am Solty. I read your post and answer it. Please return the same courtesy. While it gives good agreement, it is actually slightly optimistic. The DCS P-51 is heavier due to the tail warning radar and matches the climb performance of a 300lbs lighter variant. Bottom line is there is nothing to complain about in either FM.

Extremely offensive, immature, and uncalled for Grapejam. Please discuss this like an adult using facts to advance your argument and not an emotional plea. Do you really think it would common sense to over estimate and lie on a piece of paper promising something you could not deliver in any circumstances? Once again, it is fact that North American Aviation also underestimated the P-51's climb performance in their calculations. You will find most performance calculations are pessimistic in the performance they report. How do you explain that? A lack of common sense? :music_whistling:

Which matches Flugmechanik calculated performance..... That is not a flight test. Notice Notleistung m MW50 curve is not part of curves 1, 2, and 3, which have defined aircraft conditions according to the legend. Which is excellent agreement with the actual aircraft's performance and is only 50 fpm short of the aircrafts 3600 fpm climb rate for a example some 300lbs lighter. Yes the P-51 climb performance gives good agreement and is slightly optimistic compared to the average example. NAA also underestimated their aircraft's performance. Here we see a 10,000lb airplane should be climbing at ~3200 to 3400fpm at sea level. http://www.wwiiaircraftperformance.org/mustang/na-46-130-chart.jpg The DCS Mustang at 1066lbs climbs at 3543fpm. In the calculation NAA predicts a 9611lb airplane should climb at 3410fpm at 67" @ sea level. http://www.wwiiaircraftperformance.org/mustang/p-51d-na-46-130.html Here we see a 9760lbs airplane in a flight test achieves 3600 fpm at 67" @ sea level: http://www.wwiiaircraftperformance.org/mustang/p51d-15342.html That puts the NAA climb prediction some 5% pessimistic when compared to flight testing. As a general rule, calculated performance is almost never optimistic. Why? Making an optimistic performance estimate that the company cannot deliver on in flight makes the company look stupid and the customer unhappy. It is a great way to never sell another airplane.

Let's see. If you ran a company that guaranteed a 10% performance variation by contract meaning the customer does not have to pay for any aircraft that fall below that 10% margin....wouldn't you do something to ensure you could always meet that requirement? I would. :smilewink:

At 4175Kg..... And it should be 19.5 m/s at sea level at 4070kg.... http://www.wwiiaircraftperformance.org/fw190/Fw_190_V53_climb.jpg Which means the FM is spot on and additional climb performance is the result of additional power at 1.8ata using MW-50..... Understand? It is just physics man!!!

Kwaitek, You are a smart guy. Re-read Yo-Yo post. It is explained very well. The only data that the DCS Dora does not match is the ONE calculated performance report. That calculated report does not include exhaust thrust effects. All the flight tested data at a lower power setting; Steig u Kampfleistung; the DCS Dora matches almost perfectly. That Focke Wulf FLIGHT TESTED data is 10% better than Focke Wulf's calculated performance. There is NO flight tested data of an FW-190D9 climbing using MW-50 at 1.8ata @ 3250rpm. When you run the math it all agrees...The Dora in DCS climbs as it should with the additional power of 1.8ata @ 3250rpm. What do you propose ED does? Not model the aircraft with any additional power, just limit it to the lower power setting in a climb? :noexpression:

And what does your math say?