Why was the Boeing 377 "Stratocruiser" frequently landed nosewheel first on touchdown?

Question

Why was the Boeing 377 "Stratocruiser" frequently landed nosewheel first on touchdown? In the mid-1950's I had often observed Northwest Airlines' B377's frequently being landed that way at the old Minneapolis-St. Paul airport.

A family friend and PanAm First Officer who frequently flew the SFO-HNL run in B377's told me that (as best as I can recall now) the reason for landing the B377 in that configuration had something to do with help in "setting or unlocking the nosewheel steering" for directional use when the aircraft was fully down on the ground.

As the B377 was Boeing's prototype for the "Stratocruiser", I've wondered if their wartime B-29 "SuperFortress" also was, or could be, regularly landed nosewheel first as well?

And then, during WWII, were there any other tricycle geared two- and four-engined "heavies" that were also meant to be, or could be, landed nosewheel first?

Answer 1

Apparently, the nose first landing was necessitated by the aircraft's tendency to enter into a stall if the nose was brought up too far up. According to one of its pilots:

No amount of heaving back on the pole would induce the mainwheels to make contact first. Various explanations were offered for this peculiarity... Others pinned the blame on the pernicious lift-spoilers.

Why build a splendid wing and then fit lift spoilers? The story was that the Civil Aeronautics Administration (CAA: the FAA-to-be) would not give the type its Certificate of Airworthiness because a wing was apt to drop when the aircraft stalled. The CAA wanted the nose to drop first, and the only swift remedy was to destroy an area of lift near the fuselage.

A similar discussion can be found here. However, this seems to have changed later. From the same article:

Ironically, after BOAC had operated the type for about nine years it was decided that lift-spoilers were not necessary, and they were removed. I was then flying later types, but those who were still on Strats told me that it was then a much better-behaved aircraft.

Another thing that supports this theory is that the military version, the C-97 Stratofreighter seems to have landed normally, according to its pilot:

The control wheel is eased back at 90 mph to clear the nose wheel from the runway. The airplane will fly itself off at 100 to 120 mph depending on the load.

and

Normally the nose wheel is kept off the ground for the first thousand feet, but it can be dropped immediately for cross-wind landings.

So, this seems unique to the Stratocruiser (and its derivative, the Super Guppy). B-29s as far as I know, landed main wheels first.

Answer 2

The closest anyone came to answering this question correctly was the reference to the inboard wing spoilers mandated by the CAA (one of the reasons the aircraft's entry into service was delayed for a year). Now that we actually have a C-97 flying again in 2017/2018 we will be able to see why this procedure is used.

A lightly loaded Strat can be landed on the mains but not much before the nose touches. The recent flights of 'Angel of Deliverance' were flown very light, around 89,000 lbs so landings were not much different than in a B-29, but add payload and those spoilers and longer fuselage change everything.

Also, the spoilers were never removed on any of the commercial 377 as was mentioned before. They were mandated for the civilian operators right to the end of their service lives, including on the modified Super-Strats that PAA flew. They deployed whenever flaps were lowered 10 degrees or more, and the purpose was to deflect the airflow over the inboard portion of the wing where it met the fuselage where, unlike other aircraft types, Boeing had not added a fairing. Without the fairing any sudden changes in wing angle would disrupt airflow over the inboard wing causing a stall. Early pilots (including the CAA) quickly learned that if they attempted to flare the aircraft as they would in a Douglas or a Connie the 377 would drop like a rock onto the runway. Not exactly the thing to do with tired First Class passengers after a 9-hour flight. This behavior even occurred in flight at higher air speeds with sudden pitch inputs, and it was this problem that prompted the CAA to demand the modification.

Several solutions were attempted for the nose pitch issue including a technique developed by the Air Force where anything other than a lightly-loaded C-97 would be tipped slightly to one side (usually the upwind side) and alighted on one main and the nose. This was possible because of the 3 degree angle difference between the nose wheel and the mains. If one watched old footage of the Strat or 97 you can see this technique (look for the 1951 film 'Star Lift' starring Doris Day. Rotten movie, but fantastic Stratofreighter footage!)

The problem with the dip-a-toe technique was that the airplane would then hop around on the various gear until lift was lost, less than satisfying on a cargo hop but on a commercial flight a serious source for complaints.

It was United Airlines' pilots that found a better solution with their Mainliners. They elected to carry an additional 5 M.P.H (later knots) into the landing, roll on with the nose wheel while still supported by the wing and wait for the back end to gently settle; finally a smooth solution to the flat landing attitude. United released a color promotional film in 1950 about flying to Hawaii where the technique was clearly demonstrated (and United's CEO 'Pat' Patterson nor its senior flight managers would ever have approved a film for national theatrical release with a "bad landing"). The landing, which is supposed to be at Honolulu but is actually on Runway 28R in SFO, shows the 377 gently touch on the nose and then roll right off camera--still floating on the nose. A video taken in the 80's of a cargo C-97 in Anchorage shows it touch on the nose and the pilot deliberately hold it there with a punch of smokey power before the mains come down. Look for both on YouTube.

These days this technique is often seen with NASA's Super Guppy, which has a further elongated fuselage (and everything else!) Despite having the original nose gear replaced by a shorter but tougher 707 gear the Super Guppy must rotate and land at higher speeds and often spends several seconds rolling on the nose.

Answer 3

You are indeed correct that both the B-29 and the C-97 landed in a quite flat attitude. Randy Sohn mentions this in a report on flying FiFi for the first time:

Normal landings can be made with either 80% or full flaps. The aircraft has more of a tendency to land nosewheel first with full flaps and in fact, the first landing at Harlingen occurred this way. We used to do our short field landings this way with the C-97s, touching down precisely where we desired, although the USAF certainly viewed it with a jaundiced eye. With 25° of flaps as normally used in a crosswind it's fairly easy to strike the tailskid bumper. Any scrape marks on this heavy iron forging requires a round of beer for the crew!

Answer 4

Simple fact. Tricycle gear aircraft were never designed to be landed on the nose wheel. That fact that it was routinely done on the B-29, C-97, B377, etc. does not change this fact. At most it says it was a difficult aircraft to land CORRECTLY.

I maintain that anytime you see an aircraft land nose wheel first, it is a bad landing and nothing more.

War Department Training Film: How to Fly the Boeing B-29 Superfortress: B-29 Flight Procedure & Combat Crew Functioning

When you touch the ground the plane should be slightly tail low,. and going and going between 95 and 100 miles per hour. Notice how the main wheels bear most of the shock of Landing. Then the ship slowly settles forward. Don't apply brakes immediately, let the plane lose some of its speed rolling.

More info: Why do planes always land on rear wheels instead of the nose wheels?

Aircraft land on the main wheels. For aircraft with nose wheel it is the back ones, but for aircraft with tail wheel (also called “tail-draggers”) it is the front ones. In either case the main wheels are very close to centre of gravity and carry most of the aircraft's weight, the nose or tail wheel only carries a small fraction of it. The aircraft must land on wheels that are close to the centre of gravity (longitudinally). If they were not, the force on the wheels would create a moment that would violently pitch the aircraft. Actually, tail-draggers tend to bounce on landing a bit because there still is some moment left and in case of tail-draggers it pitches the aircraft up

Also: https://www.quora.com/Why-is-an-airplane-nose-up-while-landing

Even if you don't drive the nose gear up into the aircraft, you can still have a bad day if you touch down nose gear-first -- you might wind up "wheelbarrowing" (rolling along on your nose gear, which will caster (pivot) VERY freely and could offer you a breathtaking view of the grass next to the runway). Then again, you could emulate an aquatic mammal and "porpoise" (push down the nose gear, let it spring you backwards to bounce off the mains, which will bounce you back onto the nose gear, et cetera ad nauseum) until you (a) get sick; (b) strike the ground with the propellor; (c) collapse the nose gear, or (d) all of the above.

Answer 5

Airplanes with nose wheel touching first behavior are dangerous.

If you have to land with gusty crosswind, you may not be able to perform a perfectly smooth & tangential landing. One bounce of the nose wheel will immediately cause a pitch up momentum, increasing angle of attack. The initial bounce becomes a lift-assisted bounce. Nose wheel contact combined with yaw angle due to crosswind, will induce a yawing momentum in the wrong direction, which will increase asymmetric airflow speed between left and right wing. And that's how to start a spin at 10m above the runway.

Whatever the cause of nose wheel first touch tendency is, it may be wise to decrease average angle of incidence of the wing, by reducing flaps deflection, allowing main wheels to touch first. This immediately pitches down the aircraft and prevents bounces, this also tends to align aircraft to runway. You can start braking, steering, and stop.

One airframe modification would allow full flaps down deflection combined with slight upwards ailerons deflection, which will decrease wing's average angle of incidence.

An other better modification which also leads to a lighter airframe, is to shorten the front gear's leg.

To answer question : Why was the Boeing 377 “Stratocruiser” frequently landed nosewheel first on touchdown?

It's either because B-377 pilots frequently approach the runway way too fast, maybe afraid of stalling since there's a huge speed difference between stall speed when fully loaded, and stall speed when empty, or there is some bad design of both wing and consecutively elevator angle of incidence. First option is way more likely tu be true.