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26 votes

Why has the 777x been designed with folding wingtips?

Many modern aircraft have been designed with winglets, and older ones have been retrofitted with them. They allow a wing to produce more lift with less drag. However, the benefit is even greater if ...
fooot's user avatar
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26 votes
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Why has the 777x been designed with folding wingtips?

The Boeing 777X website states that this is to enable a more efficient wing (read: wider span) while maintaining the airport gate and taxi footprint of the classic 777 (which ensures airlines can use ...
Cpt Reynolds's user avatar
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25 votes
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May an airplane with folding wings legally taxi on the street?

When driving on roads there is no such category as flying car. You must meet the regulations for the vehicle class in question, and if the vehicle can also fly that is a separate matter. The most ...
Pilothead's user avatar
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17 votes

What are these pipelines for between the folding wing mechanism of F4 Phantom II FGR2 and Buccaneer?

Yes they are engine bleed ducts, either for anti-icing purposes, or for blowing along the flap leading edge to improve the efficiency of the flap. High temp ducts often depend on just a smooth metal ...
John K's user avatar
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14 votes

What are these pipelines for between the folding wing mechanism of F4 Phantom II FGR2 and Buccaneer?

According to the following cutaway of the Buccaneer, 53 and 67 seem to be good candidates for your answer i.e. ducts for the leading edge, aileron and flaps blowing system. According to this other ...
sophit's user avatar
  • 13.5k
14 votes

Do F-4 Phantom II pilots actually fold the wings?

As several of the comments have mentioned, the F-4 have the option of folding the outermost section of their wings, as shown in the picture below. The main purpose of this was simply to save ...
bjelleklang's user avatar
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10 votes
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Do F-4 Phantom II pilots actually fold the wings?

In U.S. Navy and Marine Corps F-4 Phantoms, the wing fold mechanism was controlled and powered by hydraulics, since the pilot had to fold the wings after landing for taxiing around on the deck. The ...
Charles Bretana's user avatar
7 votes

May an airplane with folding wings legally taxi on the street?

Unlikely. Some problems: Putting additional lights on vehicles is illegal per CVC 24003 (California Vehicle Code). You'd need an aircraft with no navigation lights, landing light, etc. Per CVC 26311, ...
Chris's user avatar
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7 votes

Why weren't the XB-70's wingtips fixed in the down position?

First, you need more wing area at low speeds in order to have a reasonable landing speed. Second, you want downward turned wingtips at supersonic speeds to create compression lift. At supersonic ...
Praying Pilot's user avatar
6 votes

Why do the wing tips on the Boeing 777X fold up instead of down?

It's not that big a deal. It's fairly easy to make a latching mechanism that is incapable of operating under load, a great example is extension ladders or an over-center dog mechanism on a ship door. ...
Harper - Reinstate Monica's user avatar
6 votes

What are these pipelines for between the folding wing mechanism of F4 Phantom II FGR2 and Buccaneer?

Manage to find this document, unfortunately don't have the full access. https://arc.aiaa.org/doi/pdf/10.2514/6.2018-0561
Daniel Yang's user avatar
5 votes

May an airplane with folding wings legally taxi on the street?

It looks like someone is seriously underestimating the complexity of this enterprise. I wouldn't be surprised if Aptera just attaches wings, propeller Aptera can also just slap antennas integrated ...
WPNSGuy's user avatar
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5 votes
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Can a 777X legally be ferried with one or both wingtips folded?

As Ron notes in the comments to another answer this is a perfect situation for a Ferry Permit/Special Flight Permit. The FAA via your local FSDO can authorize aircraft to fly for the purpose of being ...
Dave's user avatar
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4 votes

How can the 777X's longer wing reduce vortices?

So it can fit into standard size airport gates and taxiways. One reason the A380 didn't see wider adoption was it exceeded the maximum wingspan that most airports are set up for, requiring airports ...
tj1000's user avatar
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4 votes

May an airplane with folding wings legally taxi on the street?

Sure, the CAA (FAA precursor) certified the Aerocar in 1956 and 6 examples were actually produced with folding wings and a road capable car body. There is still at least one that is airworthy. Granted ...
Dave's user avatar
  • 101k
3 votes
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Why can canard wings not be used in all sonic aircraft despite their high control?

The forward canard does not replace the horizontal stabilizer, it actually forces a larger one for the same directional stability$^1$. It is also less efficient than the main wing at producing lift, ...
Robert DiGiovanni's user avatar
3 votes

In which position does Starship wings produce the most drag?

Because the Starship falls horizontally you are correct to have Cdrag rather than Clift in your equation. Based on coefficient of drag shapes here, having the fins canted down may produce more drag, ...
Robert DiGiovanni's user avatar
3 votes

Do F-4 Phantom II pilots actually fold the wings?

On our RF-4C's the pilot could not fold the wings the crew chief had to do it. It was part of the 25 hour check to fold them and inspect and lube them.
baney's user avatar
  • 81
3 votes

Were there any folding wing biplanes?

Fairey Swordfish, operated off Royal Navy carriers in WW2. Supermarine Walrus, a single engine pusher flying boat carried on cruisers. Similar vintage.
BlokeDownThePub's user avatar
2 votes

Is there any benefit to folding wings on commercial aircraft?

It looks like these wings have ends that fold up to become winglets, for drag reduction at high speed, and down to increase wing area, and thus lift, at low speed for takeoff and landing.
CCTO's user avatar
  • 205
2 votes
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Is there any benefit to folding wings on commercial aircraft?

It would allow an aircraft to have a wingspan of >80 meters yet still be able to be serviced at a standard airport gate. There are a variety of benefits to longer wingspan, but the major drawback is ...
FreeMan's user avatar
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2 votes
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In which position does Starship wings produce the most drag?

In the subsonic re-entry phase, Starship is basically falling free from the sky laying on its belly with the forward (upper) and rear (lower) fins stabilising the free fall and keeping it parallel to ...
sophit's user avatar
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2 votes
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What are these pipelines for between the folding wing mechanism of F4 Phantom II FGR2 and Buccaneer?

From Dowgwillo on boundary layer control, cited elsewhere:
Louise's user avatar
  • 144
1 vote

Why can canard wings not be used in all sonic aircraft despite their high control?

They can be used on any aircraft designed for canards. Retrofitting “all” supersonic aircraft with canards would be impractical for many reasons.
Michael Hall's user avatar
  • 26.9k
1 vote

Can a 777X legally be ferried with one or both wingtips folded?

I don’t believe Boeing authorizes flight of the 777x with a wing fold failure. To be blunt, if you can afford a \$425 million airplane, you can afford a \$30,000-\$40,000 maintenance call where an ...
Romeo_4808N's user avatar
  • 74.1k
1 vote

Can a 777X legally be ferried with one or both wingtips folded?

Not with one tip up and one tip down, but it could be possible to ferry with BOTH tips folded, or removed, if Boeing has tested it. A scenario might go like this: Airline can't get one wing tip to ...
John K's user avatar
  • 132k
1 vote

Why weren't the XB-70's wingtips fixed in the down position?

The purpose of the pivoting wingtips, which could be rotated downwards to an angle of 65 degrees from the horizontal during supersonic flight was to improve directional stability, while shifting the ...
J. Southworth's user avatar

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