Probably because of the underdeveloped runways back in the day.

So bombs could be loaded under them. Most Post-war early Soviet-period commercial aircraft were designed to be quickly converted into bombers.

FlyingElvii wrote:

So bombs could be loaded under them. Most Post-war early Soviet-period commercial aircraft were designed to be quickly converted into bombers.

Hence the clear bombardier's nose cone on so many models, right?

FiscAutTecGarte wrote:

Why did so many Russian Aircraft have such tall landing gear?

Could it be a leftover from the Tu-114 which needed those long legs due to the massive props?

WayexTDI wrote:

FiscAutTecGarte wrote:

Why did so many Russian Aircraft have such tall landing gear?

Could it be a leftover from the Tu-114 which needed those long legs due to the massive props?

Nope. Photo is of a Tu-104, this was a few years before the Tu-114 or it's Tu-95 "father" with those big props.

tu204 wrote:

WayexTDI wrote:

FiscAutTecGarte wrote:

Why did so many Russian Aircraft have such tall landing gear?

Could it be a leftover from the Tu-114 which needed those long legs due to the massive props?

Nope. Photo is of a Tu-104, this was a few years before the Tu-114 or it's Tu-95 "father" with those big props.

I know it's the Tu-104; too bad for your argument that it first flew in 1955, 3 years after the Tu-95 (1952)...

Wingtips56 wrote:

FlyingElvii wrote:

So bombs could be loaded under them. Most Post-war early Soviet-period commercial aircraft were designed to be quickly converted into bombers.

Hence the clear bombardier's nose cone on so many models, right?

1) I think it was more that the civil designs were just slightly modified bombers, to simplify design/production, rather than to literally convert airliners to bombers.

2) The clear nose was kept because it was easier in the earlier days after WWII to have a navigator in there maintaining VFR with the ground rather than set up nav beacons all over Siberia.

meecrob wrote:

Wingtips56 wrote:

FlyingElvii wrote:

So bombs could be loaded under them. Most Post-war early Soviet-period commercial aircraft were designed to be quickly converted into bombers.

Hence the clear bombardier's nose cone on so many models, right?

1) I think it was more that the civil designs were just slightly modified bombers, to simplify design/production, rather than to literally convert airliners to bombers.

2) The clear nose was kept because it was easier in the earlier days after WWII to have a navigator in there maintaining VFR with the ground rather than set up nav beacons all over Siberia.

Many Soviet passenger and cargo aircraft were quasi-military and could be modified as bombers quickly, including the AN-24/26, AN-72 and iirc the AN-12.

All three of those examples are transport aircraft, not bombers though. I agree they are designed to have the seats ripped out so they can put tanks them for transport, but there is no way that TU-104 is going to have external bombs hung from the wings. this isn't an attack aircraft.

I would say it's partly because they were required to be rough field capable but mostly due to the design of the aircraft. Look at the wings of the TU-104, 124, 134 and the 154. They are mounted very low on the fuselage and angled downwards so they need the extra ground clearance. Just a leftover design trait from the TU-16 bomber.

meecrob wrote:

All three of those examples are transport aircraft, not bombers though. I agree they are designed to have the seats ripped out so they can put tanks them for transport, but there is no way that TU-104 is going to have external bombs hung from the wings. this isn't an attack aircraft.

The Tu-104 has the exact same wings (and tail, and engines) as the Tu-16 bomber. It is basically a Tu-16 with a wider fuselage.

Remember the Tu-104 is only the second commercial jet to ever enter service (after the Comet). Early jet design was born from the military where focus was on using the new emerging technology for air superiority (ie bombers and fighters), not troop/cargo transport.

Polot wrote:

meecrob wrote:

All three of those examples are transport aircraft, not bombers though. I agree they are designed to have the seats ripped out so they can put tanks them for transport, but there is no way that TU-104 is going to have external bombs hung from the wings. this isn't an attack aircraft.

The Tu-104 has the exact same wings (and tail, and engines) as the Tu-16 bomber. It is basically a Tu-16 with a wider fuselage.

Remember the Tu-104 is only the second commercial jet to ever enter service (after the Comet). Early jet design was born from the military where focus was on using the new emerging technology for air superiority (ie bombers and fighters), not troop/cargo transport.

I get that it is adapted from the Tu-16. My point is that I'm pretty sure you could not convert the Tu-104 to carry bombs.

Somewhere I read that a distinctive feature of Tupolev aircraft is stowage of the main gear wheels in the wings rather than the fuselage.

If so, does this necessitate taller gear to create clearance between the bogeys and the top of the strut when in the stowed position?

Is the same gear assembly used on the Tu-95/114 and the Tu-104?

Don't know about "so many". Maybe on early aircraft based on military designs, but not much in airliner clean sheet designs.

HowardDGA wrote:

Is the same gear assembly used on the Tu-95/114 and the Tu-104?

No. The Tu-114 gear assembly is much bigger.

The Tu-104s have a drag parachute for short runways. Perhaps the taller landing gear is needed to keep the parachute off the ground.

SELMER40 wrote:

The Tu-104s have a drag parachute for short runways. Perhaps the taller landing gear is needed to keep the parachute off the ground.

That seems like solving a small problem with a lot of expensive engineering.

Always like an aircraft with tall landing gear, just looks better


That’s why the 787 with it’s short, stubby gear looks all wrong to me

The only two Soviet airliners with tall landing gear I can think of are the Tu-104 and the Tu-114. So "many" is quite a stretch here. In case of the Tu-114 this is quite obviously due to the huge props. The Tu-104 wing and engines were directly taken over from the Tu-16 and I guess this includes the landing gear. As the Tu-16 was a mid-wing aircraft, it does make for long legs if you use the same design for a low-wing aircraft. The later Tu-124 had quite the usual gear hight, as do all other Tupolev designs.

SELMER40 wrote:

The Tu-104s have a drag parachute for short runways. Perhaps the taller landing gear is needed to keep the parachute off the ground.

SELMER40, some of the variants of the Sud-Aviation Caravelle—I think it was the III and VI-N series—were equipped with drag chutes and the Caravelle did not have particularly long or tall landing gear, so I’m not sure drag chutes would have been the reason for the landing gear design on the TU-104.

e38

e38 wrote:

SELMER40 wrote:

The Tu-104s have a drag parachute for short runways. Perhaps the taller landing gear is needed to keep the parachute off the ground.

SELMER40, some of the variants of the Sud-Aviation Caravelle—I think it was the III and VI-N series—were equipped with drag chutes and the Caravelle did not have particularly long or tall landing gear, so I’m not sure drag chutes would have been the reason for the landing gear design on the TU-104.

e38

The Handley Page Victor also sat really low to the ground and had a massive drogue chute. B-47 too.

The gear for the Tu-104 was taken directly from the Tu-16...and I imagine if the drag chute had an issue with scraping the runway, they would have mounted it higher up, or just put bolts on it around the perimeter to impinge on the runway like they do with trailing cones for flight test. At like 180 knots, a few grams of metal isn't going to prevent the parachute from doing its job. And to address my previous posts, I'd agree that the gear is long for access to the bomb bay with vehicles...on the Tu-16.

Can’t think of any negatives with a nice tall landing gear, it gives good clearance from the possibility of tail, wingtip or engine nacelle strikes and allows for easy fuselage stretches


A short landing gear on the other hand does not and can create unforeseen consequences, no better example of those exists than the problems with the 737 Max


Boeing went back and forth on this, the 707 had a short gear and unlike the DC8 with it’s tall MLG couldn’t be easily stretched


The superb 727’s ‘stretchability’ ended with the -200 series, it had a short gear


I don’t think the designers of the original 737-100/ 200 series anticipated further stretches but they should probably have called it a day with the -800NG


The 747 had a nice tall gear with plenty of clearance all around, it allowed for a fuselage stretch finally after decades in service with the -8


The 757 had a tall gear, once again that allowed for an easy stretch to the -300 series


Not sure what Boeing were thinking with the 767 but they went back to a short gear, tail clearance wasn’t an issue with the original -200 series but it was tight with the -300 (tailstrikes have not been uncommon) and impossible without modifications on the -400


The gear had to be extended 18 inches on that aircraft along with installing taller 777 wheels and tires on the MLG take off and landing speeds had to be boosted artificially to provide tail clearance, it has been a very good aircraft in service however


The 777 was extremely well designed all around with Boeing seeming to remember the virtues of a tall gear with no issues stretching it to the -300


Back to a short, stubby gear with the 787 again though, aesthetically I don’t like it but I guess Boeing has made it work stretching all the way to the -10 series now



The A350 with it’s tall gear looks a lot better to me !

Max Q wrote:

Can’t think of any negatives with a nice tall landing gear, it gives good clearance from the possibility of tail, wingtip or engine nacelle strikes and allows for easy fuselage stretches

A huge negative: weight

dlednicer wrote:

Max Q wrote:

Can’t think of any negatives with a nice tall landing gear, it gives good clearance from the possibility of tail, wingtip or engine nacelle strikes and allows for easy fuselage stretches

A huge negative: weight

Weight is always a consideration

But if you’re unable to stretch your design because the gear is too short you’ll have to add weight anyway in the modification process

Max Q wrote:

dlednicer wrote:

Max Q wrote:

Can’t think of any negatives with a nice tall landing gear, it gives good clearance from the possibility of tail, wingtip or engine nacelle strikes and allows for easy fuselage stretches

A huge negative: weight

Weight is always a consideration

But if you’re unable to stretch your design because the gear is too short you’ll have to add weight anyway in the modification process

Indeed.

Case in point, Airbus' decision to go with almost disproportionately tall gear on the A300B1 paid off in spades, as it could be evolved/stretched all the way to the A340-600. That's a difference of almost 25 metres in length, from 50.97m to 75.36 m.

meecrob wrote:

The gear for the Tu-104 was taken directly from the Tu-16...and I imagine if the drag chute had an issue with scraping the runway, they would have mounted it higher up, or just put bolts on it around the perimeter to impinge on the runway like they do with trailing cones for flight test. At like 180 knots, a few grams of metal isn't going to prevent the parachute from doing its job. And to address my previous posts, I'd agree that the gear is long for access to the bomb bay with vehicles...on the Tu-16.

You can't just place it anywhere. Place it too high above the center of gravity, and it will start rotating the aircraft. Too low and it will slam the nose into the ground if you deploy it before the nose gear is on the ground. China had a lot of fun with this when they started developing its own versions of the MiG-19.

Starlionblue wrote:

Max Q wrote:

dlednicer wrote:

A huge negative: weight

Weight is always a consideration

But if you’re unable to stretch your design because the gear is too short you’ll have to add weight anyway in the modification process

Indeed.

Case in point, Airbus' decision to go with almost disproportionately tall gear on the A300B1 paid off in spades, as it could be evolved/stretched all the way to the A340-600. That's a difference of almost 25 metres in length, from 50.97m to 75.36 m.

That’s a very good example


Airbus has always done this right, the A320 with its tall gear is another good example, stretching the design to the A321 was no problem and later adding the much larger engines of the NEO was no issue either


Unlike the 737 Max

VSMUT wrote:

meecrob wrote:

The gear for the Tu-104 was taken directly from the Tu-16...and I imagine if the drag chute had an issue with scraping the runway, they would have mounted it higher up, or just put bolts on it around the perimeter to impinge on the runway like they do with trailing cones for flight test. At like 180 knots, a few grams of metal isn't going to prevent the parachute from doing its job. And to address my previous posts, I'd agree that the gear is long for access to the bomb bay with vehicles...on the Tu-16.

You can't just place it anywhere. Place it too high above the center of gravity, and it will start rotating the aircraft. Too low and it will slam the nose into the ground if you deploy it before the nose gear is on the ground. China had a lot of fun with this when they started developing its own versions of the MiG-19.

Hence why I said the bit about the bolts...I don't know the weight and balance of the Tu-104, but its a relatively simple engineering challenge. Also, a simple bit in the manual that says "apply brakes when parachute deployed" would solve those issues. You aren't gonna do a wheelie while braking. And this is 1950's soviet tech...I doubt it was "user-friendly"

Starlionblue wrote:

Max Q wrote:

dlednicer wrote:

A huge negative: weight

Weight is always a consideration

But if you’re unable to stretch your design because the gear is too short you’ll have to add weight anyway in the modification process

Indeed.

Case in point, Airbus' decision to go with almost disproportionately tall gear on the A300B1 paid off in spades, as it could be evolved/stretched all the way to the A340-600. That's a difference of almost 25 metres in length, from 50.97m to 75.36 m.

The 330/340 had a completely different WBF, MLG, bigger wheels/tires, and several other parts, so I don't think you can use the A300 as the baseline. Still, from the 343 to the 346 is 12 meters (20%), respectable for sure, but not a bunch more than B was able to do stretching the 777 from the 200 to the 300.

LH707330 wrote:

Starlionblue wrote:

Max Q wrote:

Weight is always a consideration

But if you’re unable to stretch your design because the gear is too short you’ll have to add weight anyway in the modification process

Indeed.

Case in point, Airbus' decision to go with almost disproportionately tall gear on the A300B1 paid off in spades, as it could be evolved/stretched all the way to the A340-600. That's a difference of almost 25 metres in length, from 50.97m to 75.36 m.

The 330/340 had a completely different WBF, MLG, bigger wheels/tires, and several other parts, so I don't think you can use the A300 as the baseline. Still, from the 343 to the 346 is 12 meters (20%), respectable for sure, but not a bunch more than B was able to do stretching the 777 from the 200 to the 300.

The A330/A340 are quite a bit more than stretches of the A300, to be sure. Hence why I said "evolved".

However, the fuselage cross-section is the same, and the height of the gear is, if not the same, then quite close. Airbus did not need to radically redesign the structure itself just to accommodate taller gear, since the gear was tall enough to begin with.

The wing-body fairing doesn't really affect the gear beyond door design. It isn't part of the structure.

So far, none of you have mentioned the landing gear on the Tupolev Tu-144, the Soviet SST . . .



Props were not an issue for this aircraft, but check out the height of that nose gear. One had to board the plane with airstairs so tall that the feeling of boarding must have been one of climbing a fire escape just to get into a building's second (or third) floor!

Starlionblue wrote:

LH707330 wrote:

Starlionblue wrote:

Indeed.

Case in point, Airbus' decision to go with almost disproportionately tall gear on the A300B1 paid off in spades, as it could be evolved/stretched all the way to the A340-600. That's a difference of almost 25 metres in length, from 50.97m to 75.36 m.

The 330/340 had a completely different WBF, MLG, bigger wheels/tires, and several other parts, so I don't think you can use the A300 as the baseline. Still, from the 343 to the 346 is 12 meters (20%), respectable for sure, but not a bunch more than B was able to do stretching the 777 from the 200 to the 300.

The A330/A340 are quite a bit more than stretches of the A300, to be sure. Hence why I said "evolved".

However, the fuselage cross-section is the same, and the height of the gear is, if not the same, then quite close. Airbus did not need to radically redesign the structure itself just to accommodate taller gear, since the gear was tall enough to begin with.

The wing-body fairing doesn't really affect the gear beyond door design. It isn't part of the structure.

Thanks for the clarification. I suppose I should have been more specific: the entire wingbox is mounted lower on the 330/340, and I'm pretty sure those two have more ground clearance than the A300, even if they look lower due to their length.

Edit: Looking at the ACAPs, it's about 30 cm difference:

A300 rear cargo door height at MRW: 3.01/2.92
A340-300 rear cargo door height at MRW: 3.27/3.18

Interestingly, the front door sill height is within a few centimeters, I wonder if they kept the same NLG design.

30 cm is similar to the Max-10 pogo gear, or 2/3 of the 767-400's extension, but given how much they got out of it, it seems worthwhile.

Ref: https://www.airbus.com/aircraft/support ... stics.html

AFAIK the wingbox isn't actually lower. The fairing is just much larger. If you look up an A330 wheel well you can see that the wing spar is way up in there.

The reason the rear cargo door is higher on the A340 is that the fuselage is not horizontal when on the ground. The tail sits higher.

Unfortunately, the A300 ACAP does not have a clearance number for the bottom of the fuselage.

Starlionblue wrote:

AFAIK the wingbox isn't actually lower. The fairing is just much larger. If you look up an A330 wheel well you can see that the wing spar is way up in there.

The reason the rear cargo door is higher on the A340 is that the fuselage is not horizontal when on the ground. The tail sits higher.

Unfortunately, the A300 ACAP does not have a clearance number for the bottom of the fuselage.

I know the 330/340 wing is deeper, so I wonder if the top skin is in a similar location and the bottom had to be extended to accommodate.

The slant on the 340 shows that the mains are bigger. The nose boarding doors on the 300/340 are at roughly the same height, so the nose legs are either the same design or the same height. If the rear cargo doors are higher on the 340, that means the mains are where the difference happens. Assuming the mains are roughly 2/3 of the way to the cargo door, then the mains on the 340 are ca 20 cm higher than on the 300.

LH707330 wrote:

Starlionblue wrote:

AFAIK the wingbox isn't actually lower. The fairing is just much larger. If you look up an A330 wheel well you can see that the wing spar is way up in there.

The reason the rear cargo door is higher on the A340 is that the fuselage is not horizontal when on the ground. The tail sits higher.

Unfortunately, the A300 ACAP does not have a clearance number for the bottom of the fuselage.

I know the 330/340 wing is deeper, so I wonder if the top skin is in a similar location and the bottom had to be extended to accommodate.

The slant on the 340 shows that the mains are bigger. The nose boarding doors on the 300/340 are at roughly the same height, so the nose legs are either the same design or the same height. If the rear cargo doors are higher on the 340, that means the mains are where the difference happens. Assuming the mains are roughly 2/3 of the way to the cargo door, then the mains on the 340 are ca 20 cm higher than on the 300.

As far as I can tell, the fuselage is not horizontal in either aircraft. The tail is higher than the nose. It just isn't as apparent on the A300 because it is shorter. Assuming the mains are the same height, this would still mean the rear cargo door is higher on the A340 given it is further back,

But I could be wrong.

Starlionblue wrote:

LH707330 wrote:

Starlionblue wrote:

AFAIK the wingbox isn't actually lower. The fairing is just much larger. If you look up an A330 wheel well you can see that the wing spar is way up in there.

The reason the rear cargo door is higher on the A340 is that the fuselage is not horizontal when on the ground. The tail sits higher.

Unfortunately, the A300 ACAP does not have a clearance number for the bottom of the fuselage.

I know the 330/340 wing is deeper, so I wonder if the top skin is in a similar location and the bottom had to be extended to accommodate.

The slant on the 340 shows that the mains are bigger. The nose boarding doors on the 300/340 are at roughly the same height, so the nose legs are either the same design or the same height. If the rear cargo doors are higher on the 340, that means the mains are where the difference happens. Assuming the mains are roughly 2/3 of the way to the cargo door, then the mains on the 340 are ca 20 cm higher than on the 300.

As far as I can tell, the fuselage is not horizontal in either aircraft. The tail is higher than the nose. It just isn't as apparent on the A300 because it is shorter. Assuming the mains are the same height, this would still mean the rear cargo door is higher on the A340 given it is further back,

But I could be wrong.

The A330 and A340 have different, longer landing gear than the A300. From this 13 year old topic below, post number 28:

A300
Nose: 105,98 inches
Main: 117,05 inches

A330/A340
Nose: 104,70 inches
Main: 159,80 inches

viewtopic.php?t=758805

hloutweg wrote:

Then I want to show how, officially the gear of the A300 differs from that of the A330.

A300 nose landing gear:


compared to A330/340


The measurements are:

105.98 inches for the A300,and
104.70 inches for the A330/340.

But observe that the main landing gear is different: A300:
https://farm4.static.flickr.com/3264/28 ... a13a_o.png

compared to A330/340:




117.05 inches for the A300, and
159.80 inches for the A330/340.

That would explain at least one reason why the A330/340 have a slope. Main landing gear is longer, and that, I suppose, is to accommodate for the A330's engines.

VSMUT wrote:

Starlionblue wrote:

LH707330 wrote:

I know the 330/340 wing is deeper, so I wonder if the top skin is in a similar location and the bottom had to be extended to accommodate.

The slant on the 340 shows that the mains are bigger. The nose boarding doors on the 300/340 are at roughly the same height, so the nose legs are either the same design or the same height. If the rear cargo doors are higher on the 340, that means the mains are where the difference happens. Assuming the mains are roughly 2/3 of the way to the cargo door, then the mains on the 340 are ca 20 cm higher than on the 300.

As far as I can tell, the fuselage is not horizontal in either aircraft. The tail is higher than the nose. It just isn't as apparent on the A300 because it is shorter. Assuming the mains are the same height, this would still mean the rear cargo door is higher on the A340 given it is further back,

But I could be wrong.

The A330 and A340 have different, longer landing gear than the A300. From this 13 year old topic below, post number 28:

A300
Nose: 105,98 inches
Main: 117,05 inches

A330/A340
Nose: 104,70 inches
Main: 159,80 inches

viewtopic.php?t=758805

hloutweg wrote:

Then I want to show how, officially the gear of the A300 differs from that of the A330.

A300 nose landing gear:


compared to A330/340


The measurements are:

105.98 inches for the A300,and
104.70 inches for the A330/340.

But observe that the main landing gear is different: A300:
https://farm4.static.flickr.com/3264/28 ... a13a_o.png

compared to A330/340:




117.05 inches for the A300, and
159.80 inches for the A330/340.

That would explain at least one reason why the A330/340 have a slope. Main landing gear is longer, and that, I suppose, is to accommodate for the A330's engines.

Awesome find. Thanks!

Also I note that the very next post was mine.

Thanks for that reference! I dug out my Norris and Wagner "A340 and A330" book, on page 68 there's a discussion of the gear:

"Another change discussed at the meeting was a possible 1'4" extension to the nose gear leg to improve ground handling...Airbus planned to introduce the longer noseleg from line 87 onwards, though the plan was later dropped when in-service experience showed it was not really needed.

SELMER40 wrote:

The Tu-104s have a drag parachute for short runways. Perhaps the taller landing gear is needed to keep the parachute off the ground.

The Caravelle had a drag chute as well but sat rather low to the ground.

Max Q wrote:

Can’t think of any negatives with a nice tall landing gear, it gives good clearance from the possibility of tail, wingtip or engine nacelle strikes and allows for easy fuselage stretches


A short landing gear on the other hand does not and can create unforeseen consequences, no better example of those exists than the problems with the 737 Max


Boeing went back and forth on this, the 707 had a short gear and unlike the DC8 with it’s tall MLG couldn’t be easily stretched


The superb 727’s ‘stretchability’ ended with the -200 series, it had a short gear


I don’t think the designers of the original 737-100/ 200 series anticipated further stretches but they should probably have called it a day with the -800NG


The 747 had a nice tall gear with plenty of clearance all around, it allowed for a fuselage stretch finally after decades in service with the -8


The 757 had a tall gear, once again that allowed for an easy stretch to the -300 series


Not sure what Boeing were thinking with the 767 but they went back to a short gear, tail clearance wasn’t an issue with the original -200 series but it was tight with the -300 (tailstrikes have not been uncommon) and impossible without modifications on the -400


The gear had to be extended 18 inches on that aircraft along with installing taller 777 wheels and tires on the MLG take off and landing speeds had to be boosted artificially to provide tail clearance, it has been a very good aircraft in service however


The 777 was extremely well designed all around with Boeing seeming to remember the virtues of a tall gear with no issues stretching it to the -300


Back to a short, stubby gear with the 787 again though, aesthetically I don’t like it but I guess Boeing has made it work stretching all the way to the -10 series now



The A350 with it’s tall gear looks a lot better to me !

Tall gear produces the following penalties:
1. Higher cost
2. Higher weight
3. More equipment needed for loading luggage/people
4. Maintenance times are extended due to the need for ladders and lifts to access what was easier before.
weight of maintenance items goes down if technicians must list above their heads.

Short gear saves money at construction and on the flight line. There is a reason the early 737, 727, and DC-9 pushed most competition out of the market. They were well engineered to reduce costs

Considering an aircraft is designed with a 15 year sales life, the fact the -10 MAX needs new gear is a small issue. I recall reading the 738 entered service with the same revision nose gear as the 737-100.

There are design reasons for tall and short gear. I am a fan of short gear as most of the flight, gear is stowed weight. There needs to be enough height, but meeting access requirements for maintenance is tough on tall gear.

Lightsaber

lightsaber wrote:

Max Q wrote:

Can’t think of any negatives with a nice tall landing gear, it gives good clearance from the possibility of tail, wingtip or engine nacelle strikes and allows for easy fuselage stretches


A short landing gear on the other hand does not and can create unforeseen consequences, no better example of those exists than the problems with the 737 Max


Boeing went back and forth on this, the 707 had a short gear and unlike the DC8 with it’s tall MLG couldn’t be easily stretched


The superb 727’s ‘stretchability’ ended with the -200 series, it had a short gear


I don’t think the designers of the original 737-100/ 200 series anticipated further stretches but they should probably have called it a day with the -800NG


The 747 had a nice tall gear with plenty of clearance all around, it allowed for a fuselage stretch finally after decades in service with the -8


The 757 had a tall gear, once again that allowed for an easy stretch to the -300 series


Not sure what Boeing were thinking with the 767 but they went back to a short gear, tail clearance wasn’t an issue with the original -200 series but it was tight with the -300 (tailstrikes have not been uncommon) and impossible without modifications on the -400


The gear had to be extended 18 inches on that aircraft along with installing taller 777 wheels and tires on the MLG take off and landing speeds had to be boosted artificially to provide tail clearance, it has been a very good aircraft in service however


The 777 was extremely well designed all around with Boeing seeming to remember the virtues of a tall gear with no issues stretching it to the -300


Back to a short, stubby gear with the 787 again though, aesthetically I don’t like it but I guess Boeing has made it work stretching all the way to the -10 series now



The A350 with it’s tall gear looks a lot better to me !

Tall gear produces the following penalties:
1. Higher cost
2. Higher weight
3. More equipment needed for loading luggage/people
4. Maintenance times are extended due to the need for ladders and lifts to access what was easier before.
weight of maintenance items goes down if technicians must list above their heads.

Short gear saves money at construction and on the flight line. There is a reason the early 737, 727, and DC-9 pushed most competition out of the market. They were well engineered to reduce costs

Considering an aircraft is designed with a 15 year sales life, the fact the -10 MAX needs new gear is a small issue. I recall reading the 738 entered service with the same revision nose gear as the 737-100.

There are design reasons for tall and short gear. I am a fan of short gear as most of the flight, gear is stowed weight. There needs to be enough height, but meeting access requirements for maintenance is tough on tall gear.

Lightsaber

Not so sure that a length in gear affects the cost of construction that much. The “pricier” bits to build are at each end of the gear- adding a few inches to a tube doesn’t cost much in materials. Materials and build are minimal costs in aviation: it’s the design and certification that generate the costs. So, arguing with myself,those taller gear cost more to design!