Hi Daan,
Getting back to you on the anomaly's of your fine work.
I switched to the 1938 version of the Fokker, and now the TSI seems to be functioning, although I do have to make fairly high rates of turn for it to read a turn. I'm a real world commercial pilot and I have encountered these old gauges about twice in my experience. They are very sensitive to turn rates about the vertical axis in measuring yaw. A rate one turn of 3°/sec should deflect the needle about 18° (one full needle width) to the left/right of top center in the direction of the turn. Since there is no DG in this aircraft it's hard to test a timed turn to determine if the deflection is correct, so this may just be my misinterpretation of the rate of heading change to the bank angles I was using in relation to airspeed. I do have realism settings to maximum, I wouldn't have it any other way...
To be clear on my reference to the MP and RPM gauges, they do both work in Prepar3D. It was just their lack of indicating any changes when leaning the mixture. When leaning the mixture on the ground at full throttle and full RPM (prop full fine), the engine audibly begins to indicate a loss of RPM but both MP and RPM remain constant at maximum RPM and MP. Further leaning continues to cause the engine sound to indicate further loss of RPM for quite a bit until finally the RPM begins to finally show a drop, but now the engine is starved of fuel and nearly failing. I tested leaning until the RPM dropped by 100 at which point the MP was still maxed out. This is not possible. Assuming the propeller is full fine when leaning, the RPM should begin to drop the moment the MP begins to drop, the two should go hand in hand at the least. Even if I assume the prop governor is limited to automatically maintaining a maximum 2,600 RPM at high manifold pressures, as I lean, the MP should begin to drop until the governor can no longer maintain the 2,600 RPM limit because engine RPM and propeller RPM are now equal; the propeller can never turn faster than the engine.
In cruise flight the test result is the same. I set MP to 90 kPa and RPM to 2,400. I began slowly leaning the mixture. Eventually I hear the engine indicating a drop of RPM, both MP and RPM maintain their 90 kPa and 2,400 respectively, this is where the problem is observed. As soon as the engine sound indicates a drop in RPM, the MP should also be reflecting this with a decrease in manifold pressure. Because the engine has a geared supercharger, there may be a slight delay. This would indicate to the pilot "peak lean" for maximum power. The RPM maintains its 2,400 because it is still being governed, this behaves as it should. As I continue to lean the mixture, the audible engine RPM continues to drop with no change to the MP, it maintains its indicated 90 kPa. Further leaning results in the the propeller RPM now beginning to drop, but still the MP indicates 90 kPa. This too is impossible. Proper behavior would be that leaning would cause the MP to start to drop from the indicated 90 kPa until the RPM is such that the governor is no longer able to maintain the 2,400 set RPM, however in reality you could never get this far because you would be doing serious damage to the engine and it would starve of fuel and quit producing power. Proper leaning method for this aircraft would be to lean until a drop of MP is first indicated and then enriched for peak MP, this would be "leaning for peak power". For "peak endurance" the mixture would be leaned such that the MP would peak and then drop and be decreased a specified amount as per the operations handbook for the aircraft, which we do not have so we would not know. It's only used when maximum fuel economy is the issue. Unfortunately this method can not be used because the manifold pressure remains constant regardless of fuel mixture settings. It only responds to throttle movement. Since there was no EGT gauge available with this aircraft, proper leaning is near impossible without proper MP indications. The best I can muster is using the first audible change in RPM. I am aware that this may be beyond the scope of what you are creating, but since other items in the aircraft behave more correctly than some payware aircraft I thought I would pass on the info as this issue could re-appear in other creations that you have in mind.
I also forgot to mention, the aircraft shakes when the aircraft is sitting on the ground without the engine running. I thought this was a hard coded effect and didn't pay much mind to it, but on one occasion after shutting down the engine, the shaking stopped. Going into the "save" menu and returning back to the flight, the aircraft was shaking again. This one time occurrence had me believing this may not be normal intended behavior.
I hope this doesn't come across as nit picking, because I'm not. Development of an aircraft should for the most part be fun! I've taken your creation from Washington D.C. to the far northern portions of Quebec as I navigate this aircraft over the North Atlantic to cross Greenland and onward to its home in the Netherlands. So far about 9 hours of flying and I have been managing just fine. The low and slow in this vintage aircraft has been a real blast.
On a side note, you mentioned that L.M. wanted a huge amount of money from you for a license. I'm not sure I understand, unless something has changed in the last year or so.
FWIW, I have a Prepar3D Professional Developers license, and it costs me $9.95 US/month. It is not required to make creations for Prepar3D, it just gives users the ability to install Prepar3D Professional on two computers with one license and get more priority support on the Prepar3D forums. Basically it gives users closer/priority contact with the L.M. devs on the L.M. support forums, nothing more. The SDK for Prepar3D is free and available to anyone regardless of which version of Prepar3D they are using, excluding Professional Plus. There is no additional costs for making content for Prepar3D than there is for FSX. All versions of Prepar3D are identical except for the Professional Plus version. It has some additional features that allow for weapons functionality. I'm not aware of any developers in the traditional flight simulation community making products with Professional Plus in mind, it appears to be mostly used by business and corporate entities, hence its massive price tag. There are individuals making content for Prepar3D with nothing more than the $59.95 Academic license. The SDK is what is used to make the content, not the version of Prepar3D you are using, it's irrelevant. In the past I was in direct contact with one of the L.M. devs and was advised the only additional costs involved in developing for Prepar3D was if one wanted direct support from L.M. on development issues. If questions from any developers are posted in the Prepar3D support forum there are no more charges than one would get from the FS Developers Forum's. I just felt it was important to include this info so that readers of this thread don't get the impression that development for P3D requires some special license that costs the user or developer any additional costs, this is just not the case. If you wish to create a version of your Fokker D.XXI using the Prepar3D SDK and you don't have the Prepar3D client software, let me know by PM and I will happily test it for you. I would hate for the Prepa3D users to miss out on your talented efforts!
Cheers, and thanks again for sharing your great efforts.
Thad
Getting back to you on the anomaly's of your fine work.
I switched to the 1938 version of the Fokker, and now the TSI seems to be functioning, although I do have to make fairly high rates of turn for it to read a turn. I'm a real world commercial pilot and I have encountered these old gauges about twice in my experience. They are very sensitive to turn rates about the vertical axis in measuring yaw. A rate one turn of 3°/sec should deflect the needle about 18° (one full needle width) to the left/right of top center in the direction of the turn. Since there is no DG in this aircraft it's hard to test a timed turn to determine if the deflection is correct, so this may just be my misinterpretation of the rate of heading change to the bank angles I was using in relation to airspeed. I do have realism settings to maximum, I wouldn't have it any other way...
To be clear on my reference to the MP and RPM gauges, they do both work in Prepar3D. It was just their lack of indicating any changes when leaning the mixture. When leaning the mixture on the ground at full throttle and full RPM (prop full fine), the engine audibly begins to indicate a loss of RPM but both MP and RPM remain constant at maximum RPM and MP. Further leaning continues to cause the engine sound to indicate further loss of RPM for quite a bit until finally the RPM begins to finally show a drop, but now the engine is starved of fuel and nearly failing. I tested leaning until the RPM dropped by 100 at which point the MP was still maxed out. This is not possible. Assuming the propeller is full fine when leaning, the RPM should begin to drop the moment the MP begins to drop, the two should go hand in hand at the least. Even if I assume the prop governor is limited to automatically maintaining a maximum 2,600 RPM at high manifold pressures, as I lean, the MP should begin to drop until the governor can no longer maintain the 2,600 RPM limit because engine RPM and propeller RPM are now equal; the propeller can never turn faster than the engine.
In cruise flight the test result is the same. I set MP to 90 kPa and RPM to 2,400. I began slowly leaning the mixture. Eventually I hear the engine indicating a drop of RPM, both MP and RPM maintain their 90 kPa and 2,400 respectively, this is where the problem is observed. As soon as the engine sound indicates a drop in RPM, the MP should also be reflecting this with a decrease in manifold pressure. Because the engine has a geared supercharger, there may be a slight delay. This would indicate to the pilot "peak lean" for maximum power. The RPM maintains its 2,400 because it is still being governed, this behaves as it should. As I continue to lean the mixture, the audible engine RPM continues to drop with no change to the MP, it maintains its indicated 90 kPa. Further leaning results in the the propeller RPM now beginning to drop, but still the MP indicates 90 kPa. This too is impossible. Proper behavior would be that leaning would cause the MP to start to drop from the indicated 90 kPa until the RPM is such that the governor is no longer able to maintain the 2,400 set RPM, however in reality you could never get this far because you would be doing serious damage to the engine and it would starve of fuel and quit producing power. Proper leaning method for this aircraft would be to lean until a drop of MP is first indicated and then enriched for peak MP, this would be "leaning for peak power". For "peak endurance" the mixture would be leaned such that the MP would peak and then drop and be decreased a specified amount as per the operations handbook for the aircraft, which we do not have so we would not know. It's only used when maximum fuel economy is the issue. Unfortunately this method can not be used because the manifold pressure remains constant regardless of fuel mixture settings. It only responds to throttle movement. Since there was no EGT gauge available with this aircraft, proper leaning is near impossible without proper MP indications. The best I can muster is using the first audible change in RPM. I am aware that this may be beyond the scope of what you are creating, but since other items in the aircraft behave more correctly than some payware aircraft I thought I would pass on the info as this issue could re-appear in other creations that you have in mind.
I also forgot to mention, the aircraft shakes when the aircraft is sitting on the ground without the engine running. I thought this was a hard coded effect and didn't pay much mind to it, but on one occasion after shutting down the engine, the shaking stopped. Going into the "save" menu and returning back to the flight, the aircraft was shaking again. This one time occurrence had me believing this may not be normal intended behavior.
I hope this doesn't come across as nit picking, because I'm not. Development of an aircraft should for the most part be fun! I've taken your creation from Washington D.C. to the far northern portions of Quebec as I navigate this aircraft over the North Atlantic to cross Greenland and onward to its home in the Netherlands. So far about 9 hours of flying and I have been managing just fine. The low and slow in this vintage aircraft has been a real blast.
On a side note, you mentioned that L.M. wanted a huge amount of money from you for a license. I'm not sure I understand, unless something has changed in the last year or so.
FWIW, I have a Prepar3D Professional Developers license, and it costs me $9.95 US/month. It is not required to make creations for Prepar3D, it just gives users the ability to install Prepar3D Professional on two computers with one license and get more priority support on the Prepar3D forums. Basically it gives users closer/priority contact with the L.M. devs on the L.M. support forums, nothing more. The SDK for Prepar3D is free and available to anyone regardless of which version of Prepar3D they are using, excluding Professional Plus. There is no additional costs for making content for Prepar3D than there is for FSX. All versions of Prepar3D are identical except for the Professional Plus version. It has some additional features that allow for weapons functionality. I'm not aware of any developers in the traditional flight simulation community making products with Professional Plus in mind, it appears to be mostly used by business and corporate entities, hence its massive price tag. There are individuals making content for Prepar3D with nothing more than the $59.95 Academic license. The SDK is what is used to make the content, not the version of Prepar3D you are using, it's irrelevant. In the past I was in direct contact with one of the L.M. devs and was advised the only additional costs involved in developing for Prepar3D was if one wanted direct support from L.M. on development issues. If questions from any developers are posted in the Prepar3D support forum there are no more charges than one would get from the FS Developers Forum's. I just felt it was important to include this info so that readers of this thread don't get the impression that development for P3D requires some special license that costs the user or developer any additional costs, this is just not the case. If you wish to create a version of your Fokker D.XXI using the Prepar3D SDK and you don't have the Prepar3D client software, let me know by PM and I will happily test it for you. I would hate for the Prepa3D users to miss out on your talented efforts!
Cheers, and thanks again for sharing your great efforts.
Thad
. It should be available soon.
