PMDG MD-11X speed at takeoff increase rapidly

[flesland 2]

Hey fellows, I have an issue with my PMDG MD11X,  when I'm taking off. I did a flight from SCEL to SAEZ with a 1:55 time flight. So i configured with a moderate load and a 15.000 Kg of fuel (33.000 lb) So according the computer onboard I have a V2+10 speed of 172 kt. but when I takeoff the speed increase so rapidly that if I want to maintain that v2+10 speed, I have to lift up the nose so much (23°-25° nose up) making the taking off phase very unreal (it looks like entering stall, very unreal). I have tried to solve this problem by increase the load and fuel, but carring too much load and extra, extra fuel.

 

I did a tutorial from London to Zürich and happen the same v2+10 issue.

 

Do i'm doing something wrong?...please help, I like this plane.

 

Best regards.

-----------------

[eNVee 14]

MD-11 has got a lot of engine power. If the planned trip is so short, loads so light, then you should use derated t/o, otherwise that high nose-up t/o is normal. Acts like rocket...  

[Noble. 142]

Firstly, you're taking way too little fuel for a 2 hour flight, you want to be landing with 8-12 tonnes of fuel on board, if I recall correctly. Also, considering you were departing with only 15 tonnes of fuel, you're going to be very light (a maximum TOW of 224t assuming you went with cargo and completely filled it up) and you have to remember this aircraft is designed to be able to depart with an addition 60t so I'm guessing you didn't de-rate the departure? In fact, quickly looking at the numbers, you can even do the maximum 60C de-rate at 223t departing from 35L @ SCEL - this will also slow the ascent rate. Having said that, the MD11 is a very powerful beast at low weights and I've done plenty of flights with it having 25 degrees nose up, there's nothing wrong with it.

 

Also, if you want to see how powerful the MD-11 is at low weights: http://www.youtube.com/watch?v=OOIg0DE9oyI

[Wendall 50]

Hi there,

 

Echoing Namejs, the MD-11 is extremely powerful. Some of my own takeoffs are crazy if I don't have a heavy load. It's just a quirk of the plane.

[squerble 300]

As per all the replies above, too little fuel. Additionally, you should derate the takeoff if you aren't already.

[Kerlix 99]

You're basically running on fumes, comparatively speaking. At weights that low (especially without derating significantly), you'd better strap in and hang on because she's gonna wanna imitate the space shuttle. 

[lodestar 186]

the pitch after take off is ususally about 20°. Maximum pitch is 25°. Just load some fuel and derate take of like  already been said

[flesland 2]

but when i did that flight I did configure the plane with derated takeoff with 51°C (123F)...so I think i use the maybe little load of fuel...thanks for replies

[hopskip 253]

Yea, 15 tonnes (metric?) of fuel is not too far off what I'd want to land with. Taking off with that is ... well I'd be wanting to land within 20 mins.

 

Don't plan to land with 0 fuel, otherwise you end up gliding to the runway and waiting for a tow to the gate.

 

Plan to land with 10 metric tonnes of fuel at your destination assuming there's no holding or go arounds or diversions.

 

I usually rotate and expect to get the nose up to 20° as standard, then pitch up or down to maintain speed. If it's light, 25° isn't unheard of till acceleration height. Flap 15 will have less drag than 22. 

 

Bit different to flying across the atlantic on an 8+ hour flight. Even there it goes up pretty quick.

[HighTowers 1,434]

Feel the power!  This is why we love to fly the MD11. Shes just fun to fly. Think fighter jet without weapons. 

 

Totally agree with everyone above. This is why a program like Topcat helps a great deal, as you can put in the weights to see where you sit, and then adjust flex temp appropriately according to how much runway would be left. 

 

Check out this FDX takeoff. 

http://www.youtube.com/watch?v=6n-GuSOekc4

[ricochetv1 0]

Too bad FSCaptain has a problem with the plane's normal pitch-up after takeoff. Every time I take off, one of the first things I hear after "Gear up" is "Good grief!". hehe

I just keep telling him to stfu!

[lodestar 186]

high pitch on take off is becouse short distances too(short for MD11). Try to load MD11 properly with aprox. 250pax and fuel for 3-4000nm, pitch will be just about 15°

[ricochetv1 0]

high pitch on take off is becouse short distances too(short for MD11). Try to load MD11 properly with aprox. 250pax and fuel for 3-4000nm, pitch will be just about 15°

Unless, of course, you're using a program like FSCaptain, which defines your pax count, cargo carried, and fuel load...

[hopskip 253]

Unless, of course, you're using a program like FSCaptain, which defines your pax count, cargo carried, and fuel load...

 

I'd hope the actual captain would determine the fuel load. Sure passengers and cargo are a function of any given airline and the fact of how many people bought tickets, so could be pretty randomly either totally full or nearly empty. (I once flew on a 767-200 that replaced a 737-300 on a flight that went tech. I think there were about 50 people on board, most of the plane was empty. I had a whole row of something like 9 seats to myself and nobody in any of the 2 rows behind or in front of me.)

 

But if some program that doesn't take into account winds, temperatures, exact routing... did I mention WINDS. Actual forecast winds... then it's not telling me what amount of fuel I'm loading!

 

PFPX on the other hand...

[3-2-1-Now 126]

Uhh - ever heard of manual thrust?

 

The thing has so much power empty, that yes, it is normal to either accelerate rapidly (shallow climb angle, relatively) or a very high pitch attitude in order to keep the speed in check against the thrust.

 

The way I handle it without proper tables for calculating FLEX is that I use full power takeoff as normal, but NO auto-throttle. I rotate to 20 degrees of pitch (keeping the gear in the airflow for additional drag), then just pull the thrust back very slightly to keep the speed in check, then gear up.

 

There is absolutely nothing saying you can not do this, because your climb angle is such that there isn't a problem with terrain avoidance.

 

Of course, if you're empty, or hauling freight, then keep on pitching! :lol: :wub:   Aerodynamically there is no reason why you can't pitch to 40 degrees if you have the power to maintain airspeed. It's all about the flow over those wings and excess thrust to defy gravity. ^_^  Just be ready to push in the event of engine failure.

 

Best regards,

Robin.