Hi David,
Firstly, I just wanted to let you know that I am greatly enjoying the Cygnus...thank you and fantastic job! I have, however, run into a problem with the fuel tank dump/selector switches in the VC:
- When I want to dump fuel from certain tanks to lighten the aircraft before landing or shift the CG, the switch will only dump from the nose tank. I tested rotating the tank selector knob to the right of the dump switch to
see if the other tanks would empty when selected...no luck. The other tanks are unaffected. I tested all six tanks and only the nose tank dumps. I have the fuel panel set to "Manual" mode when I attempt to do this. Is
there something I'm doing incorrectly on my end?
- Also, when I first load the aircraft in FSX before takeoff (when all tanks are 100% full), the "default" CG of the aircraft measures about 25 percent when the manual explains that a CG of 21-22 percent is optimal (pg. 20).
By contrast, the "default" CG of your Glowingheat SR-71A (which I also have and enjoy) measures the 21-22 percent with the tanks fully fueled. Should it be the same or at least similar for the Cygnus as well?
Thanks again for all of your hard work and help!!
-Leo
CG/Fuel Dump Problems/Questions
Moderators:fsafranek, DBushell, admin
Re: CG/Fuel Dump Problems/Questions
Edit: I just read the manual a little more closely, and found that the fuel selector knob only shows the contents of each tank, not selects which one dumps (page 17)...sorry about that!!
I also tried selecting "AFT" , "FWD", "Nose" and "Tail" tanks via the fuel panel popup screen, but again, only the nose tank will dump.
Also, when I select the forward tanks (tanks 2 and 3) to burn during flight to maintain the CG, only tank 2 shows that fuel has been consumed. Tank 3 remains full (at 10,220 lbs) even after tank 2 has been emptied by the engines and the fuel tank selector is on "FWD".
Thanks again for your patience and help!!
-Leo
I also tried selecting "AFT" , "FWD", "Nose" and "Tail" tanks via the fuel panel popup screen, but again, only the nose tank will dump.
Also, when I select the forward tanks (tanks 2 and 3) to burn during flight to maintain the CG, only tank 2 shows that fuel has been consumed. Tank 3 remains full (at 10,220 lbs) even after tank 2 has been emptied by the engines and the fuel tank selector is on "FWD".
Thanks again for your patience and help!!
-Leo
Re: CG/Fuel Dump Problems/Questions
Hi,
Will take a look at the fuel selectors on that pop up tonight - see if I can work that one out. And I will also look at fuel tank placement now we have 6 actual tanks in this flight model to see if I can adjust the fully fuelled CG slightly after verifying the details from the real manual.
For the time being, please dump fuel and use the emergency forward transfer switch to adjust the CG. Please note the real A-12 had no CG gauge! So the fuel was fed to the engines in an order set to keep CG optimal. So the only time you needed to adjust the CG was in an emergency or when the aircraft arrived at it's destination airfield with too much fuel and needed to dump!
I believe that when you select fuel dump in FS, it will dump all tanks regardless of which tank is specified, this I believe is default FS behaviour however there may be specialist gauges to do this out there - perhaps Doug Dawsons gauge.
Glad you're enjoying it.
David.
Will take a look at the fuel selectors on that pop up tonight - see if I can work that one out. And I will also look at fuel tank placement now we have 6 actual tanks in this flight model to see if I can adjust the fully fuelled CG slightly after verifying the details from the real manual.
For the time being, please dump fuel and use the emergency forward transfer switch to adjust the CG. Please note the real A-12 had no CG gauge! So the fuel was fed to the engines in an order set to keep CG optimal. So the only time you needed to adjust the CG was in an emergency or when the aircraft arrived at it's destination airfield with too much fuel and needed to dump!
I believe that when you select fuel dump in FS, it will dump all tanks regardless of which tank is specified, this I believe is default FS behaviour however there may be specialist gauges to do this out there - perhaps Doug Dawsons gauge.
Glad you're enjoying it.
David.
Re: CG/Fuel Dump Problems/Questions
Hi,
Just thought I'd let you know that I have created a new fuel popup gauge that includes tank selectors for all 6 tanks, and they are working successfully. Next I need to move one of the tanks to bring the CG back in line with the manual for take-off.
This and the other bug will be released as part of an update, which will hopefully include the D-21 version.
David.
Just thought I'd let you know that I have created a new fuel popup gauge that includes tank selectors for all 6 tanks, and they are working successfully. Next I need to move one of the tanks to bring the CG back in line with the manual for take-off.
This and the other bug will be released as part of an update, which will hopefully include the D-21 version.
David.
Re: CG/Fuel Dump Problems/Questions
Excellent! Thanks very much for taking the time to look into that, David. I really appreciate it (sorry about being so nitpicky!). Also, thank you for those tips regarding the fuel consumption and the CG in the A-12 versus the SR-71. I'll keep that in mind the next time that I fly and plan accordingly. You and the folks at Glowingheat have done an incredible job on this project. Definitely looking forward to the patch update and the M-21/D-21 version!!
-Leo
-Leo
Re: CG/Fuel Dump Problems/Questions
Hi Leo,lmeirose wrote:Excellent! Thanks very much for taking the time to look into that, David. I really appreciate it (sorry about being so nitpicky!). Also, thank you for those tips regarding the fuel consumption and the CG in the A-12 versus the SR-71. I'll keep that in mind the next time that I fly and plan accordingly. You and the folks at Glowingheat have done an incredible job on this project. Definitely looking forward to the patch update and the M-21/D-21 version!!
-Leo
Just been reading through the real life manual, and it appears I made a typo in the manual with the aircraft and I have duly corrected this!
Please see below:
Re: CG/Fuel Dump Problems/Questions
Hello, David!!
Thanks very much for the information!! Sorry to wrack your brain with the CG issue. Hope that you didn't lose much sleep trying to solve it programmatically. Glad to hear that it was just a typo in the manual!! That's great that it doesn't need too much adjustment from its takeoff configuration of 25%. It's interesting that in comparison with the SR-71, the A-12's 'default' CG fully fueled is higher. I would have thought the opposite, being that SR-71 is slightly longer and broader in the fuselage than the A-12. In any case, this information is extremely helpful and greatly simplifies the fuel transfer process I was following. In addition, the good news is that until the V1.1 update comes out, I can just set the fuel panel to "AUTO" and can maintain the proper CG (via the transfer pump switch) without having to worry about necessarily selecting individual tanks to burn fuel from to maintain the CG. Worst-case scenario: if I arrive over the field with extra fuel, I can just dump it and adjust the CG to the proper landing configuration with the transfer pump accordingly. Thanks again for looking into that and for your help!!
By the way, that's really fascinating that you have access to an original A-12 manual! What resource did you use to navigate to and access it? Is the original manual available for the public to view online? Thanks!!
Thanks very much for the information!! Sorry to wrack your brain with the CG issue. Hope that you didn't lose much sleep trying to solve it programmatically. Glad to hear that it was just a typo in the manual!! That's great that it doesn't need too much adjustment from its takeoff configuration of 25%. It's interesting that in comparison with the SR-71, the A-12's 'default' CG fully fueled is higher. I would have thought the opposite, being that SR-71 is slightly longer and broader in the fuselage than the A-12. In any case, this information is extremely helpful and greatly simplifies the fuel transfer process I was following. In addition, the good news is that until the V1.1 update comes out, I can just set the fuel panel to "AUTO" and can maintain the proper CG (via the transfer pump switch) without having to worry about necessarily selecting individual tanks to burn fuel from to maintain the CG. Worst-case scenario: if I arrive over the field with extra fuel, I can just dump it and adjust the CG to the proper landing configuration with the transfer pump accordingly. Thanks again for looking into that and for your help!!
By the way, that's really fascinating that you have access to an original A-12 manual! What resource did you use to navigate to and access it? Is the original manual available for the public to view online? Thanks!!
Re: CG/Fuel Dump Problems/Questions
I located it on the CIA reading room website released through Freedom of Information.
You can view it here https://www.cia.gov/library/readingroom ... 0001316457
You can view it here https://www.cia.gov/library/readingroom ... 0001316457
Re: CG/Fuel Dump Problems/Questions
Thanks for that helpful information David! I really appreciate it! I noticed that the library also has a flight manual for an early-model Lockheed U-2. It might prove helpful with your u-2 project:
https://www.cia.gov/library/center-for- ... r-1959.pdf
https://www.cia.gov/library/center-for- ... r-1959.pdf