Lenny777

TOPS - TAKEOFF PERFORMANCE SYSTEM FSX P3D

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I've got it.  It does what it says.  It gives the temperature for derating the takeoff for the aircraft that it covers.

Right now that is the PMDG 737NGX, the Flightsim Labs A320 and several others that are listed.

It will be working for the TFDi 717 pretty soon too, from what the developer says.

It's nice because it doesn't require a lot of input.  It reads the aircraft specs with FSUIPC, so you just have minimal data to put in.  That makes it quick and easy to get the flex temperature and it seems pretty accurate.

Bob

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I particularly love the perf. calculation option if you choose to use an intersection rather than whole runway length.  Very useful.

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Does it have lbs or just kgs for weight input?

 

I use a similar tool but it doesn't have derates just assumed temps

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6 hours ago, Richard McDonald Woods said:

Does the application consider obstacle clearance heights in its calculations?

No it doesn't.

The only thing I don't like its the metric system they use, they don't use imperial. But overall its very good and simple way of calculating.

Though I did notice that every time I ran the calculator with the same settings (weight, runway etc) the calculations became different. For example if it said assumed temperature of 34 the first time, the next time I ran the calculator with the same settings it would give me 37 the next time and 39 the next time which I found rather strange. Anybody else got that?

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Ok sounds decent. Thanks. I do have Topcat and was wondering how/if this adds anything special to flight calculations.

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14 minutes ago, Lenny777 said:

Ok sounds decent. Thanks. I do have Topcat and was wondering how/if this adds anything special to flight calculations.

Looking at the product description, it seems to add some variants that Topcat doesn't have: the 736, 739, and 77W. But it doesn't seem to do fixed derates, only assumed temp / flex.

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I took a first look at it if you guys are interested. I like the tool a lot and I think it has great potential!

 

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Just now, wsmeier said:

Looking at the product description, it seems to add some variants that Topcat doesn't have: the 736, 739, and 77W. But it doesn't seem to do fixed derates, only assumed temp / flex.

I believe you are correct. It's limited in ways, but is just something quick to use to get an assumed temperature that is figured from engine type, weight and temperature and will give you an optimal climb rate without over-stressing the engines.

I also have Topcat, which works very good for the aircraft that it covers.  The advantage of ToPS is that it gets the information from your aircraft automatically so it gives you a quick calculation of flex temp with little user input. 

It doesn't figure Vspeeds but usually the aircraft FMS or MCDU will give those anyway.  

14 hours ago, fakeflyer737 said:

Does it have lbs or just kgs for weight input?

 

I use a similar tool but it doesn't have derates just assumed temps

It uses KG for weight, but gets it automatically from the aircraft within the flightsim by FSUIPC, so there is no manual input for takeoff weight.

 

17 hours ago, Richard McDonald Woods said:

Does the application consider obstacle clearance heights in its calculations?

You shouldn't have to figure any different obstacle clearance since using an assumed takeoff temperature for the weight of the aircraft does not degrade the performance of the takeoff. You would be doing an optimal takeoff for your engine type, weight and temperature, so the aircraft is not sacrificing climb rate or performance.

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11 minutes ago, signmanbob said:

I believe you are correct. It's limited in ways, but is just something quick to use to get an assumed temperature that is figured from engine type, weight and temperature and will give you an optimal climb rate without over-stressing the engines.

I also have Topcat, which works very good for the aircraft that it covers.  The advantage of ToPS is that it gets the information from your aircraft automatically so it gives you a quick calculation of flex temp with little user input. 

It doesn't figure Vspeeds but usually the aircraft FMS or MCDU will give those anyway.  

It uses KG for weight, but gets it automatically from the aircraft within the flightsim by FSUIPC, so there is no manual input for takeoff weight.

 

You shouldn't have to figure any different obstacle clearance since using an assumed takeoff temperature for the weight of the aircraft does not degrade the performance of the takeoff. You would be doing an optimal takeoff for your engine type, weight and temperature, so the aircraft is not sacrificing climb rate or performance.

That's not true. Any reduced thrust takeoff will degrade aircraft performance vs full thrust. Sometimes an obstacle is the limiting factor in places where buildings or terrain are on the departure path. Thrust can only be reduced to the point where you can guarantee obstacle clearance in the event of an engine failure, and this is taken into account in real-world performance calculations. In most places, a field or climb limit is reached before an obstacle limit, but in places like LAS or MDW, an obstacle may very well be your limit, and your thrust reduction will be limited based on this, whereas it would be more of a reduction had it been only a field limit, climb limit, etc 

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31 minutes ago, bbain1187 said:

That's not true. Any reduced thrust takeoff will degrade aircraft performance vs full thrust. 

 

The main purpose of reduced thrust is to get optimal performance from the engine when the aircraft is below max weight, but I'm not here to argue. Think what you like.

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3 hours ago, signmanbob said:

The main purpose of reduced thrust is to get optimal performance from the engine when the aircraft is below max weight, but I'm not here to argue. Think what you like.

Reduced thrust is to save on engine wear, not for "increased" performance.

 

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7 hours ago, sultanofswing said:

Reduced thrust is to save on engine wear, not for "increased" performance.

 

You reduce the thrust of the engines to the point where it is most efficient for the weight of the aircraft, for the most optimized takeoff.  Not just to reduce the performance to extend engine life, although that is also a benefit.

If you have a light aircraft and you takeoff at full thrust, that's not the best performance.  It could even be dangerous when the aircraft engines are designed to takeoff with a max load on a short runway at full thrust.

 

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