Russia Says Its New Commercial Airliner Is as Good as Any Boeing or Airbus

Popular Mechanics ^ | June 9, 2016 | David Grossman

[C19fan]

The Russian government is getting into the business of commercial planes. The Russian United Aircraft Corporation (UAC), which is majority owned by the government, has just unveiled the MC-21 300, which it boasts will be a rival to the best planes coming out of commercial aerospace, like the Airbus A320neo and the Boeing 737Max.

[Mears]

“Winglets add efficiency on longer flights, “

—

How? (Not sarcasm—I really don’t know.)

.

[libstripper]

I remember seeing one or two documentaries that mentioned the Russians having a four engine diesel powered bomber at the beginning of the war. I don't know if it was the T2 engine. In T34 tanks it was a real winner givingbthose tanks terrific range and combat survivability.

[Mount Athos]

Something about reducing drag from turbulence, i don’t understand too well but could do a search

[CFIIIMEIATP737]

“Something about reducing drag from turbulence, i don’t understand too well but could do a search”

It has nothing to do with turbulence. And if your first statement was true about long range versus short range, at what distance is the break even point?

[r_barton]

That should work out just fine until Russia gets mad at your airline and won’t sell it spare parts.

[Mount Athos]

“It has nothing to do with turbulence.”

A 3 second internet search proved you wrong.

“Wingtip vortices create turbulence, originating at the leading edge of the wingtip and propagating backwards and inboard. This turbulence ‘delaminates’ the airflow over a small triangular section of the outboard wing, which destroys lift in that area. The fence/winglet drives the area where the vortex forms upward away from the wing surface, since the center of the resulting vortex is now at the tip of the winglet.”

“And if your first statement was true about long range versus short range, at what distance is the break even point?”

Here’s what I found:

“In simple terms, if your average sector length is short (less than one hour) you wont get much the benefit from winglets - unless you need any of the other benefits such as reduced noise or you regularly operate from obstacle limited runways.”

http://www.b737.org.uk/winglets.htm

[CFIIIMEIATP737]

No. Turbulence is a violent movement of a fluid, such as air or water. Winglets don’t create violent movements of air.

Winglets reduce induced drag. Winglets increase the effective area of a wing.

Winglets provide benefits while the aircraft is still on the runway during the production of lift. That is why your statement about hurting/helping is incorrect.

Do you have any idea what my screen name, CFIIIMEIATP737 means?

[Mount Athos]

If you would like to learn more about how winglets work by reducing wingtip turbulence, check out this article from Popular Science I found.

“They’re called winglets, AND THEIR PURPOSE IS TO REDUCE TURBULENCE AT THE TIPS OF AN AIRPLANE’S WINGS. The air pressure on the bottom of a wing is greater than the pressure on top, so when air flowing across the two surfaces meets at the wing tip, it forms a vortex-a miniature tornado. The vortices created by a large airplane are strong enough to flip a smaller plane that is following too closely.”

http://www.popsci.com/military-aviation-space/article/2002-02/fyi-what-are-winglets

[CFIIIMEIATP737]

Mr. Athos, I was trying to be nice.

Earlier you posted winglets create turbulence. Now you quote Popular Science saying they reduce turbulence.

You look stuff up on the internet. I do this for a living.

My screen name represents Certificated Flight Instructor, Instrument Instructor, Multiengine Intructor, Airline Transport Pilot, Type rating Boeing 737. I am type rated in several other jets.

I train professional pilots. I have advanced degrees in aeronautical science.

You don’t know what your talking about. Quit looking up stuff on the internet that contradicts itself and maybe listen to those of us who have a lifetime of experience on the subject.

[Mount Athos]

“I train professional pilots. I have advanced degrees in aeronautical science.”

That’s cool.

You’re also completely wrong when you say that Wingtips have nothing to do with turbulence.

Moving the turbulence from wingtip vortices away from the wing where they reduce lift is the key to how wingtips work.

“Earlier you posted winglets create turbulence. “

That’s not true.

I didn’t say winglets create turbulence, I cited a passage that said WINGTIP VORTICES cause turbulence. That would include wings that do not have winglets at all:

“Wingtip vortices create turbulence, originating at the leading edge of the wingtip and propagating backwards and inboard. This turbulence ‘delaminates’ the airflow over a small triangular section of the outboard wing, which destroys lift in that area. The fence/winglet drives the area where the vortex forms upward away from the wing surface, since the center of the resulting vortex is now at the tip of the winglet.”

[Mount Athos]

“You’re also completely wrong when you say that Wingtips have nothing to do with turbulence.”

I meant to say instead:

“You’re also completely wrong when you say that Winglets have nothing to do with turbulence.”

[Mount Athos]

Second correction:

Moving the turbulence from wingtip vortices away from the wing where they reduce lift is the key to how winglets work.

(I also see this explanation is confirmed in the patent applications for winglets)

[CFIIIMEIATP737]

Wow, I’m getting a real education here! I’ve spent my whole aviation career teaching students about drag,coefficients of lift and I never knew that all this time it was that darn turbulence out there slowing the plane.

Since I have obviously met someone who knows more about aviation than I do, could you elaborate on your comments in post #26 about how winglets affect noise and obstacle clearance?

[Mount Athos]

"Since I have obviously met someone who knows more about aviation than I do, could you elaborate on your comments in post #26 about how winglets affect noise and obstacle clearance?"

Sure! The wisdom of the 3 second internet search wins against the credential king again.

Source is boeing -- what do they know?

----

BLENDED WINGLET PERFORMANCE IMPROVEMENTS

Depending on the airplane, its cargo, the airline's routes, and other factors, blended winglets can:

* Improve takeoff performance and OBSTACLE CLEARANCE, allowing airlines to derate engine thrust.

(Winglets let planes take off from runways in a shorter distance as shown in this boeing chart)



REDUCTION IN EMISSIONS AND COMMUNITY NOISE

At airports that charge landing fees based on an airplane's noise profile, blended winglets can save airlines money every time they land. The noise affected area on takeoff can be reduced by up to 6.5 percent. With requirements pending in many European airports for airplanes to meet Stage 4/Chapter 4 noise limits, the addition of blended winglets may result in lower landing fees if the winglet noise reduction drops the airplane into a lower-charging noise category. The noise reduction offered by blended winglets can also help prevent airport fines for violating monitored noise limits.

http://www.boeing.com/commercial/aeromagazine/articles/qtr_03_09/article_03_1.html

[CFIIIMEIATP737]

That’s great, Mr. Athos!

Now how about winglets and drag reduction?

[RedWulf]

Cost a lot less?

[Mount Athos]

“Now how about winglets and drag reduction?”

Sure!

“Wingtip vortices create turbulence, originating at the leading edge of the wingtip and propagating backwards and inboard. This turbulence ‘delaminates’ the airflow over a small triangular section of the outboard wing, which destroys lift in that area. The fence/winglet drives the area where the vortex forms upward away from the wing surface, since the center of the resulting vortex is now at the tip of the winglet.”

This effect is demonstrated in this national geographic video:

http://www.youtube.com/watch?v=CnvIf3vFEYA

[CFIIIMEIATP737]

Man, you knocked it out of the park with that one!

So let’s review:

Winglets reduce drag.
Winglets reduce noise.
Winglets help with obstacle clearance.
Winglets help with turbulence.

So an aircraft manufacturer would be an idiot not to include winglets in the design or their aircraft, right?

[Mount Athos]

No! Recall my first comment in this thread, pointing out that winglets increase efficiency on long haul routes, but can decrease efficiency on short haul.

I happen to live in an area with some very short haul flights, the planes on these routes do not have winglets.

http://airinsight.com/2012/04/10/winglets-a-triumph-of-marketing-over-reality/

“While more efficient at high altitude, for many flights on the US east coast and west coast, where heavy traffic areas exist, a flight may not get above FL270, and never reach the altitude at which the efficiency of winglets kicks in. And at those lower altitudes, cruising at more than M0.71 will result in an increase in fuel consumption because of the weight of the winglets and parasitic drag.”

In addition, winglets add weight to the wingtips of an aircraft, more than 1,000 pounds for a typical Boeing. This has an impact on the strength of the wing, effectively weakening wing torsional rigidity and introducing aeroelastic issues that must be compensated for, currently accomplished by the installation of about 100 pounds of depleted uranium in the leading edge to reduce the twist on the wing generated by the winglet installation. A basic 737 has a high gust tolerance, well in excess of regulatory standards, but one modified with winglets will lose much of that margin above regulatory requirements.

A rule of thumb for most aircraft is that its cost is about 3% of any additional weight carried in fuel each hour. For a winglet equipped aircraft, operating on short-haul routes with virtually no fuel efficiency benefit, a winglet equipped aircraft could, depending on operating procedures, have a negative, rather than positive, impact on fuel economy.

If you don’t believe the numbers, run a flight plan for a short-haul flight that doesn’t go above FL330 for a winglet and non-winglet equipped aircraft. The fuel differential will be about 0.5% better, not the 5% commonly repeated by pundits in the industry.

The position we take is not unique. Russian aerospace, for whom winglets are not a new technology or idea, have decided not to use them on the Sukhoi SuperJet or on the forthcoming MC-21.

The reality is that the payback for winglets will take about 10 times longer than marketing brochures would imply, unless all your flights are long-haul operations operating above FL390. For Air New Zealand’s 767s, winglets make perfect sense for their long-haul operations. For short-haul domestic operations, one must question the payback of winglets, which certainly isn’t going to be quick with a 0.5% fuel benefit. We wonder whether taking on 1,000 pounds of revenue belly cargo, rather than saving 0.5% of fuel with winglets, might generate a better economic result for an airline.

[There also is increased risk of runway overrun on landing with winglets:]

Winglets add lift to the wings, which results in faster speeds for the aircraft in ground effect. While jets typically increase speed by 7-8 knots in ground effect, winglets exacerbate that process, with speed increases of 10-12 knots once power is off. Without different operating procedures, it is easier to overrun a runway in a winglet equipped aircraft than one without winglets, as the speed change in ground effect can increase landing distances. And because winglets generate additional lift, the effectiveness of braking can be minimized unless pilots pull back on the yoke to firmly transfer weight from the nose wheel to the main gear and wings, which is not a part of normal operating procedures at many airlines. The potential for a runway overrun is more significant with a winglet equipped aircraft unless operational procedures are modified, as evidence by a couple of recent events.

[CFIIIMEIATP737]

So that turbulence thing we talked about isn’t important? Noise reduction isn’t important? Obstacle clearance isn’t important?

Any why are we only talking about airliners? What about corporate aircraft, single and twin engine piston aircraft, military aircraft, etc.?