I am using TOPCAT and the NGX with great precision!Remember to have pneumatic pressure running through the aircraft, ideally from the APU(APU bleed on).Also remember to use real world weather in both TOPCAT and FSX when calculating the take off data for a specific runway.I would say that I have 0,1% accuracy at best. But 0,3% is not bad at all! Set the thrust at 0,3% higher than recommended for added safety :)

That much i know about those engines, that setting thrust +0.3% doesn't mean +0.3% rate :) well, but if we go to that line, then we dont need topcat because then we are using absolutely wrong de-rates and by then even more wrong runway margins. Now that is called a FAIL. Look at page 102 at this dockument.

Edited January 30, 201214 yr by Kazzukki

Kazukki, make sure you have same configuration in TOPCAT as in FSX in regards to anti-ice etc.FMC will show different values if you have for ex. packs on or antiice off when entering the data, it will correct before takeoff after air system configuration.

You mis read my post, I am refering to TOPCAT, I don't think it has an "NGX" option

These options only refer to the loads. Perf calc is always the same, and a real deal from FPPMs. Valid to within meters/maximum one knot to real calculators a certain charter airline uses - I have checked.

I am almost exclusively flying the -700's, but am actually finding TOPCAT to be off as far as 3-5% N1. I am setting TOPCAT to the same weight/balance as in the sim, using the same configuration and verifying that all weather parameters match. Then I enter TO/1/2 and the assumed OAT calculated from TOPCAT and the NGX shows an N1 3-5% higher.

Not to be devil's advocate here but does anyone here use the old method? I mean PMDG/Boeing were generous enough to give us the performance charts so can't you interpolate the correct N1 from there? I know you have to do the math yourself but surely it's possible...I know, I know....don't call me surely...

I am almost exclusively flying the -700's, but am actually finding TOPCAT to be off as far as 3-5% N1. I am setting TOPCAT to the same weight/balance as in the sim, using the same configuration and verifying that all weather parameters match. Then I enter TO/1/2 and the assumed OAT calculated from TOPCAT and the NGX shows an N1 3-5% higher.

That's because Topcat's -700 assumes 22k engines and the -700 NGX has 24k engines with a 26k bump. So basically TO in Topcat equals TO-1 in NGX and TO-1 in Topcat equals TO-2 for the -700 NGX. Ben

That's because Topcat's -700 assumes 22k engines and the -700 NGX has 24k engines with a 26k bump. So basically TO in Topcat equals TO-1 in NGX and TO-1 in Topcat equals TO-2 for the -700 NGX.Ben

Well that just cleared things up for me. TOPCAT is useless to the NGX. Seems to work for me with the Maddog though and flaps 11 for instance.I am sorry but i am alone in the cockpit with not the luxury of a co-pilot doing the math so maybe we want a Software add-on that can handle this ?PMDG make it and we will all buy it i believe :-) Remember the 747 MD-11 and the 777Michael

Edited January 31, 201214 yr by Michael Moe

That's because Topcat's -700 assumes 22k engines and the -700 NGX has 24k engines with a 26k bump. So basically TO in Topcat equals TO-1 in NGX and TO-1 in Topcat equals TO-2 for the -700 NGX.Ben

exactly !Guys i'm doin a tutorial vid right now and should be up before the end of the day .

I am almost exclusively flying the -700's, but am actually finding TOPCAT to be off as far as 3-5% N1. I am setting TOPCAT to the same weight/balance as in the sim, using the same configuration and verifying that all weather parameters match. Then I enter TO/1/2 and the assumed OAT calculated from TOPCAT and the NGX shows an N1 3-5% higher.

Try calculating with TC's altimeter set to 29.92 and of course anti-ice and packs to match with simulations. Thats my problem. When calculating N1 rates, weight and flap settings are partly irrelevant as they only change the needed RWY margins ect. something else. Correct me if i'm wrong.

Hi, I have a question related to TOPCAT and sorry to hack to the thread like this, OK, at the W&B page and at the fuel load section, there are "Estimate" button, doing the obvious fuel estimation for the trip? however, I couldn't find anywhere a place to insert the cruise altitude, which doesn't make sense to me, so am I missing something ?Thanks

Hi, I have a question related to TOPCAT and sorry to hack to the thread like this, OK, at the W&B page and at the fuel load section, there are "Estimate" button, doing the obvious fuel estimation for the trip? however, I couldn't find anywhere a place to insert the cruise altitude, which doesn't make sense to me, so am I missing something ?

Note the name of the button: "Estimate"Estimate is another word for 'guess'.Basically, TOPCAT is a takeoff and landing calculator, not a fuel planner, but they put that feature in there to help you out if you needed a rough guess of how much fuel. Therefore, it's not going to have fuel planner accuracy, or any of the advanced inputs for wind/altitude/etc.

Well that just cleared things up for me. TOPCAT is useless to the NGX.

Definitely not, TOPCAT works great for the NGX., provided you select TO or TO1 derate. Those are equivalent to TO1 and TO2 of NGX. Unless you fly to severly restricted airports, where you can always use flight manuals, it will give you very good results.

When calculating N1 rates, weight and flap settings are partly irrelevant as they only change the needed RWY margins ect. something else. Correct me if i'm wrong.

Definitely they are not irrelevant. The de-rate N1 is calculated so, that at that specific weight and flap setting, you are just in the limits, be it runway performance, obstacle performance or climb performance.

Basically, TOPCAT is a takeoff and landing calculator, not a fuel planner, but they put that feature in there to help you out if you needed a rough guess of how much fuel. Therefore, it's not going to have fuel planner accuracy, or any of the advanced inputs for wind/altitude/etc.

Very much so. That will be what the PFPX will do, once it is out.

Definitely they are not irrelevant. The de-rate N1 is calculated so, that at that specific weight and flap setting, you are just in the limits, be it runway performance, obstacle performance or climb performance.

But is that why they use the assumed temperature? What i mean is that in my TOPCAT (2.70), it makes no difference to calculated TO N1 rate that what I put to Take-Off Weight Box or flap settings. Just the Margin changes and there will be more or less options in D-TO. Same at TO-1 and TO-2. For exmpl. if i put 44000 kg in TOW, it will calculate 96.5 or +32 91.3 but if i change TOW to 70000 kg, it still shows 96.5 or +32 91.3%. I think that there is something that I dont know :D

That is indeed strange. What are the other variables you are using, (wind, temperature, QNH, airport, runway) so I can check.

That is indeed strange. What are the other variables you are using, (wind, temperature, QNH, airport, runway) so I can check.

Ok lets take hmmm. EDDF with some random variables.Wind 040/05Temp +0 CAltimeter 28.80inHgRWY Condition DRYRWY 07LAll calculations below at Air Conditioning ON and Anti Ice OFF--------------------------------------------------Now let's calculate with different options:**************************************************Take-Off Weight: 44000 kgFLAPS 5Thrust Config: TO-------------------------------------------------OAT +0 96.5%D-TO +30 91.6%D-TO +36 90.7%D-TO +40 90.2%****************************************************************************************************Take-Off Weight: 65000 kgFLAPS 5Thrust Config: TO-------------------------------------------------OAT +0 96.5%D-TO +30 91.6%D-TO +36 90.7%D-TO +40 90.2%****************************************************************************************************Take-Off Weight: 44000 kgFLAPS 10Thrust Config: TO-------------------------------------------------OAT +0 96.5%D-TO +30 91.6%D-TO +36 90.7%D-TO +40 90.2%****************************************************************************************************Take-Off Weight: 65000 kgFLAPS 10Thrust Config: TO-------------------------------------------------OAT +0 96.5%D-TO +30 91.6%D-TO +36 90.7%D-TO +40 90.2%****************************************************************************************************Take-Off Weight: 44000 kgFLAPS 5Thrust Config: TO-2-------------------------------------------------OAT +0 90.1%D-TO +30 85.6%D-TO +36 84.7%D-TO +40 84.2%****************************************************************************************************Take-Off Weight: 65000 kgFLAPS 5Thrust Config: TO-2-------------------------------------------------OAT +0 90.1%D-TO +30 85.6%D-TO +36 N/AD-TO +40 N/A****************************************************************************************************Take-Off Weight: 44000 kgFLAPS 10Thrust Config: TO-2-------------------------------------------------OAT +0 90.1%D-TO +30 85.6%D-TO +36 84.7%D-TO +40 84.2%****************************************************************************************************Take-Off Weight: 65000 kgFLAPS 10Thrust Config: TO-2-------------------------------------------------OAT +0 N/A (Take-Off Weight (65000 kg) exeeds Perf. Limit Weight (64569 kg)D-TO +30 N/AD-TO +36 N/AD-TO +40 N/A**************************************************If you want some additional information, please let me know :)

Now let's calculate with different options:

OK lets do it!

**************************************************Take-Off Weight: 44000 kgFLAPS 5Thrust Config: TO-------------------------------------------------OAT +0 96.5%D-TO +30 91.6%D-TO +36 90.7%D-TO +40 90.2%**************************************************

I show limiting option +64C 59646 OBS© 115-116 116 120 2706M 86.3%

**************************************************Take-Off Weight: 65000 kgFLAPS 5Thrust Config: TO-------------------------------------------------OAT +0 96.5%D-TO +30 91.6%D-TO +36 90.7%D-TO +40 90.2%**************************************************

I show limiting option+54C 65215 CLIMB 143 143 144 1649M 87.6%

**************************************************Take-Off Weight: 44000 kgFLAPS 10Thrust Config: TO-------------------------------------------------OAT +0 96.5%D-TO +30 91.6%D-TO +36 90.7%D-TO +40 90.2%**************************************************

I show limiting option+65C 56078 CLIMB 114 114 119 2725M 86.2%

**************************************************Take-Off Weight: 65000 kgFLAPS 10Thrust Config: TO-------------------------------------------------OAT +0 96.5%D-TO +30 91.6%D-TO +36 90.7%D-TO +40 90.2%**************************************************

I show limiting+47C 65181 CLIMB 140-141 141 142 1877M 88.6%So it looks good with me, but looking at it, my +40 derate is at 89.6% and full thrust is 95.9%What version of TOPCAT do you use?