I was taking a look at pictures of the MAX and I remembered reading in related threads about the type that landing gear height limited engine size and rotation angles on take off especially for the MAX9 and the MadMAX.

My understanding is that the MAX10 will have a different style of gear that will help ground clearance and rotation angle that hasn’t been publized yet by Boeing.

Would it be possible to apply lifts (hydraulic or electric) to the gear such that the gear could be raised when down to allow for higher ground clearance, (possibly larger engines?) then lowered when retracted to fit in the wheel wells.

I imagine it would increase weights slightly but I imagine the gear to be used on MAX10 will be heavier than the MAX7-9.

I’d imagine this to be similar to the folding wingtips to be employed on the 777X.

How viable would this option for the MAX or feature aircraft ?

77H

The issue of raising the height of the landing gear revolves around the increased loads associated with the main strut which acts like a lever arm. You increase the length, you increase the weight and you increase the lever arm. If we consider aircraft are generally highly optimised small changes can have very substantial effects on supporting aircraft structures.

The -10 MAX landing gear function is explained some in this article: https://en.wikipedia.org/wiki/Boeing_737_MAX#737_MAX_10

Found these that seem to explain the concept of levering and telescoping the -10 max landing gear. It does look like the strut telescopes shorter and possibly moves slightly forward during retraction.

Boeing shows some videos at PAS:

https://twitter.com/thatjohn/status/877101578888589313
https://twitter.com/jonostrower/status/ ... 9319045121

The solution looks to be a lot more refined than using additional hydraulics. From what I could see, it is done by changing the geometry of some of the landing gear components.

Now if they could lower the location of the flight interphone jack it would be great. Even the -8MAX is taller than NextGen. When you unplug the interphone ground cord when you launch (for flight) a -8 MAX, I'm about 5 foot 11 and had to stand on my tip toes and could barely reach the top latch to secure external power/interphone panel door.

stratclub wrote:

The -10 MAX landing gear function is explained some in this article: https://en.wikipedia.org/wiki/Boeing_737_MAX#737_MAX_10

Found these that seem to explain the concept of levering and telescoping the -10 max landing gear. It does look like the strut telescopes shorter and possibly moves slightly forward during retraction.

Boeing shows some videos at PAS:

https://twitter.com/thatjohn/status/877101578888589313
https://twitter.com/jonostrower/status/ ... 9319045121

The solution looks to be a lot more refined than using additional hydraulics. From what I could see, it is done by changing the geometry of some of the landing gear components.

Now if they could lower the location of the flight interphone jack it would be great. Even the -8MAX is taller than NextGen. When you unplug the interphone ground cord when you launch (for flight) a -8 MAX, I'm about 5 foot 11 and had to stand on my tip toes and could barely reach the top latch to secure external power/interphone panel door.

They should just put an auxiliary jack on the nose gear somewhere. That way they can keep commonality to an extent. But I don’t think they’ll do that.

jetmatt777 wrote:

stratclub wrote:

The -10 MAX landing gear function is explained some in this article: https://en.wikipedia.org/wiki/Boeing_737_MAX#737_MAX_10

Found these that seem to explain the concept of levering and telescoping the -10 max landing gear. It does look like the strut telescopes shorter and possibly moves slightly forward during retraction.

Boeing shows some videos at PAS:

https://twitter.com/thatjohn/status/877101578888589313
https://twitter.com/jonostrower/status/ ... 9319045121

The solution looks to be a lot more refined than using additional hydraulics. From what I could see, it is done by changing the geometry of some of the landing gear components.

Now if they could lower the location of the flight interphone jack it would be great. Even the -8MAX is taller than NextGen. When you unplug the interphone ground cord when you launch (for flight) a -8 MAX, I'm about 5 foot 11 and had to stand on my tip toes and could barely reach the top latch to secure external power/interphone panel door.

They should just put an auxiliary jack on the nose gear somewhere. That way they can keep commonality to an extent. But I don’t think they’ll do that.

That would do the trick, me thinks. Communality for parts that are rarely or never replaced isn't really an issue. Check out the solution that Boeing came up with for the -10 MAX being longer. Looks like a really clever bit of engineering. Impressive stuff, really.

Makes you wonder why Boeing didn’t develop this earlier

The -800 / 900 and 900 ER could all have benefited from a taller main landing gear, the lower take off and landing speeds and improved runway performance that would have provided


Not to mention a better looking aircraft on the ground and less tailstrikes.


This will be a side benefit on the -10, aesthetically a tall landing gear always improves an aircraft


And why the 787 with its short gear looks stumpy on the ground

Max Q wrote:

Makes you wonder why Boeing didn’t develop this earlier

The -800 / 900 and 900 ER could all have benefited from a taller main landing gear, the lower take off and landing speeds and improved runway performance that would have provided


Not to mention a better looking aircraft on the ground and less tailstrikes.


This will be a side benefit on the -10, aesthetically a tall landing gear always improves an aircraft


And why the 787 with its short gear looks stumpy on the ground

Develop what exactly? Add addition complexity to the landing gear that is not needed? The next Gens and earlier meet all of their as designed performance requirements as proven through FAA validation testing. Other than adding addition weight, how are tall gear a benefit to an aircraft that performs as designed? Aesthetics? Not really a consideration in aircraft design. As it is, tail strikes are extremely rare.

With only some scant details, it seems that the MLG will incorporate something similar to what the A340 MLG has which retracts the shock strut during the retraction sequence to allow the MLG to fit in the existing wheel well. If designed right, it would have little negative impact to dispatch reliability as it is a fully mechanical system. It will increase the overhaul costs by only a few manhours and add a few new bushings to be replaced. Not a big deal in my opinion.

Erau82 wrote:

With only some scant details, it seems that the MLG will incorporate something similar to what the A340 MLG has which retracts the shock strut during the retraction sequence to allow the MLG to fit in the existing wheel well. If designed right, it would have little negative impact to dispatch reliability as it is a fully mechanical system. It will increase the overhaul costs by only a few manhours and add a few new bushings to be replaced. Not a big deal in my opinion.

As with the 340, so also the 330.

It's called the "shortening mechanism", but for no good reason if it malfunctions the message is "lengthening fault".

Now I wonder where Airbus got that idea for their A340/330 from. Could i suggest. from Concorde which had shortening devices on both main Landing gears