Lancaster and Halifax with tricycle landing gear

MatthewB

Banned
The Tudor used as many components of the Lincoln as possible but used a new fuselage where the wing location could be chosen, so why did they choose a tailwheel undercarriage for this aircraft?
I suppose they went with what was working. Perhaps the Lincoln, York and Shackleton were initially designed for grass strip operations, if only for staging and taxiing if not takeoff and landings.

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Unlike a taildragger’s big fat wheels upfront, a nose wheel equipped aircraft may push itself deep into the wet grass when sitting or taxiing.

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I wasn't challenging anyone to find the exceptions. I'm only observing that most have single main wheels
It is a timing thing.

Tricycles start coming in as engines get powerful enough to handle the extra weight.

As aircraft get bigger you need more wheels to decrease ground pressure. Here is a good example.
https://en.wikipedia.org/wiki/Convair_B-36_Peacemaker#Landing_gear

Both events happened at about the same time so large aircraft with both tricycles and single wheels are fairly rare.
 
Perhaps the Lincoln, York and Shackleton were initially designed for grass strip operations, if only for staging and taxiing if not takeoff and landings.


Unlike a taildragger’s big fat wheels upfront, a nose wheel equipped aircraft may push itself deep into the wet grass when sitting or taxiing.

Possibly but it didn't seem to matter much when the B.1/39 bomber designs were done.
 

MatthewB

Banned
Possibly but it didn't seem to matter much when the B.1/39 bomber designs were done.
That seems like an odd comment, considering that the nose wheel bomber was rejected. I would argue the nose wheel mattered a lot to determining which aircraft were chosen. Likely the Air Ministry’s Specification did not mention landing gear at all, but instead focused on performance.

Besides, the Bristol proposal looks a generation behind the Lancaster and Halifax, with no tail or nose turrets. I suppose major mods like we saw between the early streamlined B-17 and the later heavily armed models would be possible for the Bristol, but really I’d say they’re better off focusing on making Beaufighters.

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It looks more Italian or German to me, like a Piaggio P.108 with a twin tail.

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That seems like an odd comment, considering that the nose wheel bomber was rejected. I would argue the nose wheel mattered a lot to determining which aircraft were chosen. Likely the Air Ministry’s Specification did not mention landing gear at all, but instead focused on performance.

Besides, the Bristol proposal looks a generation behind the Lancaster and Halifax, with no tail or nose turrets. I suppose major mods like we saw between the early streamlined B-17 and the later heavily armed models would be possible for the Bristol, but really I’d say they’re better off focusing on making Beaufighters.

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It looks more Italian or German to me, like a Piaggio P.108 with a twin tail.

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Not so much rejected as like all the B.1/39 designs, all of which had nose wheel undercarriage, pushed out by the need to build something as the war was on, and not having the time at this time to continue to develop something from scratch.

With the turret location, the spec required a heavy cannon armament of 4 x 20mm cannon in turrets, given the turret to be used by ALL the B.1/39 spec bombers - flat and round, a conventional nose and tail turret was not possible. If you do a search for the B.1/39 'Ideal Bomber' spec and look at the designs, they all use the same flat round turret with 4 x 20mm cannon and all are in more or less the same dorsal and ventral positions.
 
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MatthewB

Banned
Can you share the B1/39 Specification with us? Did it call for a nose wheel? If not, I’d suggest the designers forgot about grass field ops.
 
Can you share the B1/39 Specification with us? Did it call for a nose wheel? If not, I’d suggest the designers forgot about grass field ops.

Not sure of the exact wording but the B1.39 spec was to carry 9,000lb over 2,500miles cruising at least 280mph. Maximum bomb load was to be 10,000lb and some could be carried externally if necessary. Provision was made to stow 20 x 250lb or 500lb bombs, 10 x 1,000lb bombs, 5 x 2,000lb AP bombs, 2 2,000lb SCI containers or 10 small bomb containers. The 20mm cannon were drum fed with 30 rounds per drum, 5 drums per gun and an additional reserve supply of 20 drums per turret was to be carried but not necessarily in the turret. The aircraft was to be stressed to carry alternate turrets with 2 40mm cannon each with 110 rounds of ammunition. Armstrong Whitworth, Blackburn, Bristol, Fairey, Gloster, Handley Page, Avro, Shorts and Vickers all produced designs with Hercules, Griffin or P.24 engines.

Take off from a grass field in still air to clear a soft obstacle when carrying 9,000lb of bombs and fuel for 2,500 miles was to be made in not more than 900 yards.

One correction on the undercarriage statement, Shorts proposal was a standard tail wheel
 
Need to shift main gear aft of COG, thus moving wings. Would be a total redesign. The basic concept is there, but not used by British aviation.
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May I disagree with you dear SwampTiger?

I challenge that - when converting from tail-wheel to tricycle landing gear - you do not need to move wings relative to the rest of the airframe (e.g. fuselage) ..... rather you only need to move the main wheels farther aft - relative to the centre of gravity (cargo hold) and centre of lift (wings).

I am thinking of all the Cessnas converted by Met-Co-Air and Beech 18s converted by Volpar.
Met-Co-Aire took regular main landing gear legs and moved them aft while adding new nose wheels. Met-Co-Aire changed hardly anything above the floor boards.
Both those after-market retrofits became factory standard as soon as customers learned how much easier they were to land.
 
I challenge that - when converting from tail-wheel to tricycle landing gear - you do not need to move wings relative to the rest of the airframe (e.g. fuselage) ..... rather you only need to move the main wheels farther aft - relative to the centre of gravity (cargo hold) and centre of lift (wings).
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Flipped retraction direction and position within the nacelle
 

MatthewB

Banned
I wonder if the erstwhile traildragger Shackleton pilots ever forgot they were flying a new tricycle type.
 
Sorry, I meant from the start.

Yes it was not use in British aviation at the time but three years later all the 15.38 airliner specs and all B1.39 bomber specs used tricycle undercarriage and Shorts was looking at it for its 15/38 spec, so most of the British aviation industry had decided this is the way to go, so what can be done to make that happen sooner?
Have the British aviation industry actually keep up to date with modern developments? The DC-4E was flying with a tricycle gear in 1938 with a design start 2-3 years earlier. Tricycle gear was fairly well understood by that point.

Less facetiously I think the expectations regarding airfields may have been a factor, since the hope was to use smaller grass airstrips to both save money on the infrastructure budget and allow operational flexibility in terms of deployment abroad. That got discarded in the rush for performance at any cost, and I think if that was accepted a few years earlier it’s possible the industry may have moved earlier.
 

trurle

Banned
What would it take for the Lancaster and the Halifax to have tricycle landing gear rather than tail wheel landing gear and would this change any of their operations?
Need to shift main gear aft of COG, thus moving wings. Would be a total redesign. The basic concept is there, but not used by British aviation.
I do agree moving wings is not a practical redesign.

As alternative, original under-wing chassis had wheel nearly at leading edge. Reversing undercarriage opening direction for wheels to open under trailing edge would give enough stability margin at takeoff. And landing is typically not a problem as remainder of fuel can be transferred to most forward tank.
Of course, this arrangement is heavier because of larger distance between wheel and main wing structural members, and because front wheel tends to be much heavier compared to tail wheel. Overall, may be additional 300-500kg weight.

More severe problem in redesign is what front gear would interfere with bomb-sight compartment. Also, handling at landing and takeoff will become terrible due more forward center of drag, but it may be partially compensated by lower landing speed allowed by more pitch-up landing attitude.

Operationally, more accidents but less fatalities and write-offs are expected for tricycle landing gear option.
 
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I do agree moving wings is not ............ Also, handling at landing and takeoff will become terrible due more forward center of drag, but it may be partially compensated by lower landing speed allowed by more pitch-up landing attitude.

Operationally, more accidents but less fatalities and write-offs are expected for tricycle landing gear option.
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Insurance statistics disagree with your conclusion.

Tricycle airplanes are MORE stable on landing and suffer fewer ground-loop accidents. Because their main wheels touch down first - and are aft of the centre of gravity - they tend to stabilize/minimize any sideways drift, steering the airplane towards the runway’s centre line. By the time they are slow enough to lower the nose wheel, the worst instability has been damped.
OTOH tailwheel airplanes are inherently unstable during touchdown. Main wheels forward of the C. of G. tend to exaggerate any sideways drift and point the airplane towards the weeds. Tail wheel pilots need to dance vigorously on rudder pedals to keep their airplanes tracking the centre of the runway.
 

trurle

Banned
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Insurance statistics disagree with your conclusion.

Tricycle airplanes are MORE stable on landing and suffer fewer ground-loop accidents. Because their main wheels touch down first - and are aft of the centre of gravity - they tend to stabilize/minimize any sideways drift, steering the airplane towards the runway’s centre line. By the time they are slow enough to lower the nose wheel, the worst instability has been damped.
OTOH tailwheel airplanes are inherently unstable during touchdown. Main wheels forward of the C. of G. tend to exaggerate any sideways drift and point the airplane towards the weeds. Tail wheel pilots need to dance vigorously on rudder pedals to keep their airplanes tracking the centre of the runway.
You should take into account the problem of low tail inherited from tail-dragger airframe, and poor handling before touchdown due more forward center of drag. The touchdown of nose wheel in converted Lancaster (as opposed to purpose-designed tricycle aircraft) will happen faster, and timing of nosewheel touchdown will be poorly controlled due crews generally not having experience with tricycle gear, small pitch angle margin in convertible, and larger pitch attitude errors due handling difficulties before touchdown. As i remember from private talks with pilots (which was part of my prior work as avionics engineer), the "three-points landing" and associated bounced landing was common for tricycle landing gears early on, especially for relatively small aircraft which have low angular inertia. "Three-points landing" is rarely fatal on smaller (compared to modern airliners) and nearly empty bomber aircraft, but damage to landing gear would be quite common.

https://en.wikipedia.org/wiki/Bounced_landing#Factors_favouring_bounced_landing
https://agairupdate.com/three-point-vs-wheel-landings/
 
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Sounds like a problem that could be solved by a few hours of practice with an instructor pilot.

P.S. I am a private pilot and have read Pazmany’s Volume One on Landing Gear Design.
 

trurle

Banned
Sounds like a problem that could be solved by a few hours of practice with an instructor pilot.

P.S. I am a private pilot and have read Pazmany’s Volume One on Landing Gear Design.
I would say rather "a several tens hours of practice, and at least thirty practice landings" to make proficient pilot. One more problem is what British bomber planes did not have dual controls, therefore special training versions have to be built.
On the other hand, Avro Lancaster And H.P. Halifax were one on the more survivable heavy bombers in WWII, with average loss 2.1% and 2.2% per sortie, respectively. Therefore, you can expect better-than-average quality of pilots for them. For comparison, contemporary Short Stirling had 4.0% loss per sortie.
Of course, severity of problems with training for tricycle gear landing hinges on date of upgrade. IOTL, Avro Lancaster which first went off assembly lines in late 1941 is doomed to have pilot training problems, but it can be easier if H.P. Halifax is upgraded in similar manner in late 1940.
 
When was the originally hoped for in service dates for the B.12/36 and P.13/36 designs?

The Short Stirling was built to B12/36 and was the back up design if the Supermarine Bomber didnt work out. Stirlings got into service early 1941.
 
The Short Stirling was built to B12/36 and was the back up design if the Supermarine Bomber didnt work out. Stirlings got into service early 1941.

But when the specs for both the B.12/36 and P.13/36 aircraft were issued, when was the hoped for in service date.
 
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