NowCorporate

I think it would be really neat if we could put the G550 engines on my buddys batman airplane, which has the super efficient 7X type wing. Then I bet it gets the same range as the Fusion Global FBW, which will outlfy the G650.

Ziggy

Most operators would plan routes to stay within an acceptable range of adequate airfield in case of emergencies. The most crucial emergencies dealing with degraded aircraft performance. So far everyone has been quick to point out just the loss of power in an OEI situation. But what about performance. Basic multi engine doctrine taught that with an engine failure on a twin aircraft. Not only did you lose half the power, but suffered an 80% degradation in aircraft performance. This being because now the failed engine is dead weight creating only drag. Most twin jets have nacelles and engines that have bigger surface area than the competing 3 or more aircraft.
So when you lose an engine on a trijet sure you've only lost 1/3 the power, but performance wise. Smaller engine, less weight, less drag. This probably means you can continue to cruise at higher altitudes and speeds for the given weights, temperatures, and etc. It was about 2 years ago that British Airways 747-400 lost an engine on departure out of LAX and continued it's flight to London. Would an twin engine whatever have done that? I am only using the BA flight as an example, I am not commenting on whether is was wrong or right.

tuna hp

I'd add that in addition to drag from the dead engine, you also have your centerline of thrust way out to the side at the nacelle with the working engine. So you have to waste a lot of energy to fly straight. Trijet, if you lose the center engine you still have centered thrust. If you lose an outside engine, the centerline of thrust is still only half way to the nacelle, so you should have to waste less energy to fly straight.

Maybe, but what if when people are designing airplanes, when they have a twinjet versus a trijet they know that they are going to be able to have 20% more thrust so they are able to build a bigger wing for the plane. And when an engine goes out they'll have somewhat less thrust to weight than the trijet, but they'll have more wing to weight. Which is safer?

geosynchronous

QuietSpike,

I simply compared the top-of-the-line Falcon product with the top-of-the-line Gulfstream product- both of which are suited to global operations. You have the right to disagree with my research of the two products that I chose (with a supporting macro breakdown from an outside source.) However, simply disagreeing without backing yourself up with data makes for a weak retort...

To that end, fly safe and remember:

"It is the mark of an educated mind to entertain a thought without accepting it"

-- Aristotle

(that was a compliment to you)

Ziggy

Traditionally I am a fan for having more wing. But this usually pertains to the mid-size aircraft size. Again for better runway, and hot & high performance. However with more wing comes more lift, and more drag. Both induced and parasitic. Also while larger wings are more conducive to takeoff performance, they are a hinderance in the high speed flight regime. It all comes down to what you're trying to accomplish performance wise for the aircraft.

tuna hp

Unless the more wing and more engine allows them to climb higher where there air is thinner... I think it would be interesting to understand that tradeoff, I doubt anyone on this forum understands it.

QuietSpike

Geo...dont take this the wrong way!!

I used to sell gulfstreams... it was my job to know their performance and limitations along with each and every competitor out there. to say I "know" about these planes is an understatement...

To change someone's mind in a forum like this would take an act of congress (and even then, you know they wouldnt get it done!)

So I just gave up... I had given my two cents, it was discarded... no hard feelings!

-spike

QuietSpike

Good point Tuna!!

Look at the U-2.. huge wing area, and ultra-high performance (albeit slllooowww).

Look at the G550 wing-- huge wing area (against other similar planes), and has low ref speed and high cruise speed. The G650 will be similar-- completely new wing, but similar ref speeds and a .90 normal cruise!

The G550 has huge wing, great climb performance, and great cruise performance.... and not leading edge slats... that has to say something about the designers!!

galaxy flyer

The real advantage of three engines is, in the event of OEI, one is not required to land, one can continue, if the performance allows. That is, you have the MEA accounted for. In the end, once an engine dies, a twin is now a single-engine plane not going far. ETOPS is a consideration for everyone who wants to run a airline-grade operation.

The BA 747 is an example of four-engine capability.

GF

QuietSpike

So I guess you are saying the lockheed jetstar was the safest bizjet because it had 4 engines...

This is like a Motor Trend debate--- my car has 8 cyl engine... oh yeah, mine has 12, so it must be better...

doesnt work that way!