Why don't 777s have winglets?

**lauchit** · 09-19-2003, 01:49 AM

Anyone can answer that question? I've search so many places yet can't find the answer about that.... Theoretically the use of winglets can help to reduce wake turbulence underneath the wing. Then why doesn't the Boeing company implement such design in their 777s?

Chit

**jmagyar** · 09-19-2003, 05:18 AM

You really want to know??

The 777 was not designed with winglets. At the time Boeing chose to increase the span of the wing rather than add winglets. As increased span also increases wing aspect ratio [another measure of efficiency] Boeing outlined the addition of winglets did not overcome the weight penalty of carrying winglets. Sources have since shown that increasing the span of the wing by 4/5 of the height of the winglet will have a similar effect on induced drag as a winglet, though without the added complexities of extra outboard structure, extra weight and extra cost.

Quote from http://airtransportbiz.free.fr/ Or Air transport Business Website.

**chasw** · 09-19-2003, 07:31 AM

Now that's an answer, and a great question! Let's have some more of this kind of stuff in the forum please!

**flyinggriffin** · 09-19-2003, 08:45 AM

There are a number of excellent books on aerodynamics. One conclusion they all seem to come to is that there is no such thing as a free lunch. When you optimize one thing on an aircraft you pay in another area.

Woulnd't it be be nice to have a light g/a plane that could go 200knots, have 1000 mile range, but still only burn about 5 gallons an hour and carry four full size adults.

**rtriez** · 09-19-2003, 08:55 AM

>Now that's an answer,
>and a great question!

>Let's have some
>more of this kind of stuff
>in the forum please!

But in the proper forum ;-) The OM is just the place for something like this. Don't mean to be a buzzkill, but we are trying to keep congestion down by instilling in everyone's thought processes what goes where.

I'll leave it open, but just an FYI for next time....

Regards,

Bob

**chasw** · 09-19-2003, 09:52 AM

>There are a number of excellent books on aerodynamics. One
>conclusion they all seem to come to is that there is no such
>thing as a free lunch. When you optimize one thing on an
>aircraft you pay in another area.
>
>Woulnd't it be be nice to have a light g/a plane that could
>go 200knots, have 1000 mile range, but still only burn about
>5 gallons an hour and carry four full size adults.

Diamond Aircraft already make one, and shortly two. Is there a model of a DIESEL engined Diamond for FS9 anywhere on the net? I was talking to a friend the other day about diesel/jet fuel aero engines (one of his pet raves) and he mentioned their new DA-42 twin prop. Haven't seen many Diamod aircraft modelled in FS.

**chasw** · 09-19-2003, 12:43 PM

>They do? :)
>
>http://www.diamondaero.com/da40specs.htm
>
>The 4-place sure has a nice looking interior though!
>
>Ladamson

They do - and they do!

http://www.diamondair.com/contentc/TwinStar1.htm

Chas

**lauchit** · 09-20-2003, 12:55 AM

Then why is Boeing putting the winglets back in their 777LRs and ERs?

Chit

**bjmcintyre** · 09-20-2003, 08:31 AM

>>They do?
>>
>>http://www.diamondaero.com/da40specs.htm
>>
>>The 4-place sure has a nice looking interior though!
>>
>>Ladamson
>
>They do - and they do!
>
>http://www.diamondair.com/contentc/TwinStar1.htm
>

But they don't. In the sheet you specified, it burns over 2x as much fuel as the original statement (1000nm, 4 adults, 200kts, 5 gph) What you posted has 1079nm, 4 adults, 201kts (max cruise) and 10.7gph (11.8gph at 200 kts). Still... close.

Brian