Guest

Tri-engine Aircrafts

Mon May 24, 1999 2:12 am

Hi :



I personally experienced that the three-engined aircrafts climb and fly better than all the other aircrafts. In other words, the DC-10 and MD-11 are more powerful than B767-300ER and B-777 when taking off. Although they consume more fuel than the others, they give a better performance ...

What do you guys think ...

Andy
 
cedarjet
Posts: 8101
Joined: Mon May 24, 1999 1:12 am

RE: Tri-engine Aircrafts

Mon May 24, 1999 10:44 am

a tri-jet is less powerful and has a lesser max climb performance than a twin. To be certified for operation, a new plane must be able to climb with one engine out. So a 757 must be able to climb with half of it's power lost, whereas an MD11, TriStar or 727 must be able to climb with only a third of it's power lost (not sure of exact rule on 4 engine designs). You can see that the power in reserve on a twin is correspondingly higher, and a twin would be able to outclimb any trijet, let alone any 4-engine design. This is why in some circles (the author included), twins are safer than 3- and 4-engine designs because most accidents occur on take-off and landing, virtually never over the ocean. The greater power-to-weight ratio in a twin gives an extra margin of power when it may be most needed.
fly Saha Air 707s daily from Tehran's downtown Mehrabad to Mashhad, Kish Island and Ahwaz
 
JETPILOT
Posts: 3094
Joined: Tue May 18, 1999 6:40 am

RE: Tri-engine Aircrafts

Mon May 24, 1999 11:34 am

You can't possibly evaluate the performance of the aircraft you were on. You don't know the factors involved to determine performance. What was the density altitude, the weight of the aircraft. Was it a max power takeoff or a reduced power takeoff. Was there a climb gradient to be met. Were noise abatment procedures in effect. These factors change with every aircraft form flight to flight. The performance of the jet is impossible to estimate from a passenger who know none of the variables.