Why winglets

[bafanguy]

mar,

Got the PM...thx. RPM/Kfactor=BHP/BMEP. Don't tell 'em here what it means...knowledge is power.

 

[TonyC]

mar,

Got the PM...thx. RMP/Kfactor=BHP/BMEP. Don't tell 'em here what it means...knowledge is power.

Did you mean RPM?

 

[bafanguy]

DARN !!! Messed up my own joke...story of my life...

 

[enigma]

I have an interview coming up in the near future and a friend of mine was asked the following question:

Why doesn't the 777 have winglets.


It was after he was asked what the winglets do, and what the purpose was.

His answer to the first question was: To safe fuel. Installed on modern aircraft. (and a few other things).Then the interviewer said: "Why not on a 777 then".

Any inputs would be greatly appreciated

Frix, winglets are a great way to enhance the performance of an existing wing design. They allow the aerodynamicist to gain the span effects of a longer wing, without gaining the root bending effects of a longer wing. In other words, if an engineer needs to upgrade his airplanes performance with wingspan, winglets let him do so without having to change the basic wing structure. He can't just add span, that would demand increased structure and the attendent weight.

The 777, as well as the CitationX, and Falcons don't need winglets because their wings were engineered properly to begin with. Please don't misunderstand, there are numerous examples of properly engineered wings getting winglets added later in life, but those applications exist where the wing is being asked to work harder than it was originally designed to work. For example, the Lear Longhorn wing is just the original Lear 23 wing with some aero mods and the tipsails (Lear name for winglets). Lear added the tipsails to a wing originally designed to lift around 15000 pounds as a way to get more work. Their redesign worked, because the Longhorn wing was eventually fitted to the 23000 pound Lear 60.

There are other valid reasons to design the wing for winglets in the beginning. One reason would be room, the wing can be made shorter with the winglet, allowing for easier hangar-ability, better ground manuverability, etc.

The best way to make the point is to look at the wings of the most efficient/highest performing aircraft. They generally don't have winglets. Examples would be the 777, the aforementioned Falcons, CitationX, etc.

regards,
enigma

 

[banned username 2]

Re: Re: Why winglets

The 777, as well as the CitationX, and Falcons don't need winglets because their wings were engineered properly to begin with.

Hehehehe... This can only mean ONE thing about the Gulfstream wings!

(Running to duck for cover before GVFlyer arrives on scene!)

 

[Frix]

Winglets

Wow,
You look away from your PC for a few days. Thanks a bunch for the inputs. Even though not all of the replies were about winglets, I still enjoyed reading them.

Fly safe. (with or without those darn things)

 

[CaSyndrm]

Cause they look cool and chicks dig them...

 

[ThomasMore]

> Max. Dem X/W

Bad crosswind technique...

 

[TopGun-MAV]

depends on the design of th aircraft. they are there for stablilty and also they reduce the flow of high pressude air to the low pressure area.

just my 2 cents

 

[Dizel8]

I meant to ask you, what is "Lauch", a new austrian lite beer or....?

 

[Dizel8]

I meant to ask you, what is "Lauch", a new austrian lite beer or....?

 

[GVFlyer]

\

The 777, as well as the CitationX, and Falcons don't need winglets because their wings were engineered properly to begin with. Please don't misunderstand, there are numerous examples of properly engineered wings getting winglets added later in life, but those applications exist where the wing is being asked to work harder than it was originally designed to work...The best way to make the point is to look at the wings of the most efficient/highest performing aircraft. They generally don't have winglets. Examples would be the 777, the aforementioned Falcons, CitationX, etc.

regards,
enigma

I just found this post. You should have begun it with, "Once upon a time," as most fairytails begin. The GV wing was developed with winglets by Gulfstream scientists on the same Boeing computers that had been used for 777 development. Final development was accomplished at the NASA Langley wind tunnel. The wing is a beautiful design unmatched by any aircraft in the industry. The entire top surface is a single bonded piece of extruded aluminum. It is an all lifting design including the radius going into the winglet, there are no washed-in or washed-out areas and no stalled regions. The winglets provide a forward thrust vector. There are no leading edge devices required to provide a min. Vref of 110 knots or any canoes needed to hide flap gear. The wing develops even more lift than the computers had predicted necessitating the addition of vortices generators to the horizontal stabilizer.

The proof is in how the aircraft performs. The G550 at maximum gross weight, 91,000 lbs., will always initially climb to at least 41,000 feet. 51,000 feet is available for up to the last 3 hours of flight. With 8 passengers, the G550 will fly 6750 nm at M.80, 6500 nm at M.83, 6000 nm at M.85 and 5,000 nm at M.87. How does this compare to the, "most efficient/highest performing aircraft" referenced in your post?

The Citation X is such an aeronautical blunder that with 8 passengers on board range is reduced by two-thirds at max speed. Low speed controlability has been such an issue that a series of aerodynamic patchs have been applied to improve safety. This has not been enough to keep one Midwestern Citation X operator from deeming them unsafe and parking theirs until they are sold.

GV