Was a pre-war, larger DH Albatross ever considered? (2 Viewers)

[Admiral Beez]

And I think we are forgetting that the DH Albatross was originally designed to be a trans Atlantic Mail carrier,

Trans Atlantic? Wikipedia gives the Albatross a range of 1,070 miles. It's 2,345 miles from Great West Aerodrome (LHR) to the closest North American airport of Gander, NL (opened in 1938), and at the Albatross's normal cruising altitude of 10,000–15,000 feet, on the way out we'd be flying against the prevailing North Atlantic westerlies. If we remove the passengers and fittings, can we reduce the weight and get in enough fuel to increase endurance by 120%?

 

[cammerjeff]

Trans Atlantic? Wikipedia gives the Albatross a range of 1,070 miles. It's 2,345 miles from Great West Aerodrome (LHR) to the closest North American airport of Gander, NL (opened in 1938), and at the Albatross's normal cruising altitude of 10,000–15,000 feet, on the way out we'd be flying against the prevailing North Atlantic westerlies. If we remove the passengers and fittings, can we reduce the weight and get in enough fuel to increase endurance by 120%?

I didn't say it met the original specification, just that what what it was designed for, the specification as far as I can tell was 36/35 for a transatlantic Mail Plane, I can't seem to find out much more about it.

And I agree that it probably won't extent the range by that amout.

 

[Shortround6]

Trans Atlantic? Wikipedia gives the Albatross a range of 1,070 miles. It's 2,345 miles from Great West Aerodrome (LHR) to the closest North American airport of Gander, NL (opened in 1938), and at the Albatross's normal cruising altitude of 10,000–15,000 feet, on the way out we'd be flying against the prevailing North Atlantic westerlies. If we remove the passengers and fittings, can we reduce the weight and get in enough fuel to increase endurance by 120%?

1938 "Janes" describes fuel capacity for the trans-Atlantic mail role as four 330 imp gal tanks (1500l) in the fuselage, two on each side of the central gangway. As passenger carriers
they were given two tanks in the bottom of the fuselage. A 270imp gal tank (1277l) forward of the wing and 170gal (773l) tank aft of the wing.
Mail plane may have operated overloaded. In the weight breakdown they are claiming 3040lbs for 408 imp gal (know it doesn't agree) in passenger versions and 4186lbs for passengers, luggage, mail and freight. Crew was four men but that included a steward.
0nly two were completed as mail-planes and rest as passenger aircraft. Mail carriers had fewer windows and I have no Idea of what else may have been take out (seats, bulkheads, insulation, galley accessories
I have no idea of the gross weight of the mail-carriers but they were planning to increase the fuel capacity by 200%.
Edit] Mail carrier planes might not have had to meet the same standards as passenger aircraft? As in take-off distances and ceiling and engine out situations?

 

[MikeMeech]

Trans Atlantic? Wikipedia gives the Albatross a range of 1,070 miles. It's 2,345 miles from Great West Aerodrome (LHR) to the closest North American airport of Gander, NL (opened in 1938), and at the Albatross's normal cruising altitude of 10,000–15,000 feet, on the way out we'd be flying against the prevailing North Atlantic westerlies. If we remove the passengers and fittings, can we reduce the weight and get in enough fuel to increase endurance by 120%?

Hi
Wikipedia has its limitations, the 1939 edition of 'Aircraft of the British Empire' by Leonard Bridgman has 3,300 miles for the mail plane:

The 1987 Edition of 'De Havilland Aircraft since 1909' by A J Jackson has 3,230 miles for the mail plane:

However, the same author in his 1988, reprinted with corrections, edition of 'British Civil Aircraft since 1919 Volume Two' has 3.300 miles:

Arthur W J G Ord-Hume in his 2003 book 'British Commercial Aircraft' also has 3.300 miles:

I would suggest that 3,300 mile range for the mail plane is probably the most correct.

Mike

 

[Simon Thomas]

The cruise speed of the Albatross was faster than the DC-3 & DC-3A's of the same era.

167 knots = 192 mph

 

[EwenS]

"The British Aircraft Specification File" has this to say about Spec 36/35 written around the DH91 Albatross:-

"An Experimental Transatlantic Mailplane with extra fuselage tanks, to permit the carriage of 1,000lb of payload for 2,500 miles against a 40 mph headwind at 210 mph. The wooden stressed skin construction consisted of lamination of cedar ply with a thick layer of balsa between, and cemented under pressure in a special jig. The one-piece cantilever wing was built around a stress bearing box spar, with a thick planning of spruce applied diagonally in two layers. It had a retractable electrically-operated undercarriage and (in its initial form) tall inset fins and rudders. Apart from the extra fuel tanks, there were other minor differences between the Mailplane and passenger versions, with the latter having additional windows and slotted instead of split flaps.

De Havilland sought financial assistance from the Air Ministry for the construction of a 200 mph four-engined passenger plane. four-On 21/1/36, an order was placed by the Air Ministry for two experimental Transatlantic Mailplane to Specification 36/35. K8618 and K8619 were allotted under Contract no. 458574/35 But were not taken up.

The prototype D.H.91, E-2/G-AEVV, first flew at Hatfield on 30/5/37. Following some problems and modifications to both prototypes, five 'F' Class aircraft were delivered to Imperial Airways (commencing on 17/10/38 with G-AFDI), followed by tgevtwo long-range mail carriers, G-AEVVPlane on 29/9/38 and G-AEVW on 3/7/40.

Performance Mailplane;

Maximum speed : 213mph
Cruising speed: 205mph
Initial rate of climb: 620 ft/min
Service ceiling: 16,800ft
Range: 3,230 miles
AUW: 28,500 lbs

Performance Passenger Plane
Maximum speed : 225 mph
Cruising speed: 210 mph
Initial rate of climb: 700 ft/min
Service ceiling: 17,900 ft
Range: 1,040 miles
AUW: 29,500 lbs

Engines: Four 525 hp Gipsy Twelve Series I inverted V engines, with D.H. two-bladed controllable-pitch airscrews.

Crew of four, with mail or 22 passengers."

The comment in Alex Lumsden's "British Piston Engines and Their Aircraft" about the Gipsy Twelve was

"The Gipsy Twelve, or King of 1936 was a double Six, an inverted, supercharged and geared Vee-12. Because of the outbreak of war in 1939 and the big building programme for the Gipsy Major, installed in Tiger Moth and Magister trainers, it did not achieve the success expected."

As well as the Albatross, these engines went into the DH93 Don trainer (only 30 of which flew). Approx 90 of these engines were produced.

 

[Shortround6]

I would suggest that 3,300 mile range for the mail plane is probably the most correct.

I would too, but 70 miles out 3300 miles could be the difference between a couple of bad spark plugs

Thank you for all the work you did in scanning and posting those pages.
A sort of structural problem for the Albatross is that they never used the wing structure for fuel storage. All fuel was either under the cabin floor or inside the main cabin.
DH was pushing the envelope in wood construction and building such a large all wood unbraced monoplane was certainly quite an undertaking and gave them a lot of knowledge when they came to design the Mosquito.

Early DC-3s could hold up to 822 US gallons in the wings, freeing up volume in the fuselage.

 

[Shortround6]

Transport aircraft are all over the place when it comes to cruise speeds and ranges.

DC-3 is especially bad in this regard because they used two different basic engines, the 9-cylinder R-1820 and the 14-cylinder R-1830 but they used different models of each engine depending on when they were manufactured, customers preference and sometimes the routes they were flying on. They also seem to have expanded the fuel capacity fairly early from 650 gallons to the 822 gallons but many routes only required 600 gallons or less and more cargo could be loaded on the shorter routes.
Speeds and ranges differed from the early 930hp T-O (850 max cruise) engines to the later 1200hp T-0 (1000hp max cruise) engines. Best cruise altitude also changed with engines.
Many airlines in later years cut cruising speeds to get a lower fuel burn as the DC-3s were operating on shorter, less prestigious routes as new planes (post WW II) took over.
DC-3s with the R-1820 engines could vary from 93-94 gph at 75% power and 184mph to 112gph at 75% power and 198 mph depending on engine model.

 

[tomo pauk]

The comment in Alex Lumsden's "British Piston Engines and Their Aircraft" about the Gipsy Twelve was

"The Gipsy Twelve, or King of 1936 was a double Six, an inverted, supercharged and geared Vee-12. Because of the outbreak of war in 1939 and the big building programme for the Gipsy Major, installed in Tiger Moth and Magister trainers, it did not achieve the success expected."

(my bold)

Sir Alex either gives too much of the credit to the engine, or he takes the expectations of the engine division of D-H as facts.
The Gipsy Twelve combined the lavish layout of a 'normal' V12 engine with the bad power/weith ratio and low power (and especially power at altitude) - meaning that it will never be choosen as a mainstream engine for the British. One can warm-over the ww1 engine tech only for so much.

Whomever decided to pull the plug out, made an excellent call.

 

[Shortround6]

The Gipsy Twelve was an expensive and complicated way to get 500-525hp, except that the Cylinders, heads, valve gear, pistons and piston rods were already in production for the in-line 6 cylinder and in-line 4 cylinder engines.
This was a common way for the 4/6 cylinder air cooled engine companies to try to break into the over 200hp market and compete with the 300-500hp air cooled radials. It didn't really work long term. It kept initial costs low but also restricted development potential.
An inline 6 was going to be heavier than a radial 5 or 7 cylinder engine. It was also going to be harder to keep cool. The V-12 was going to be heavier than the radial 7-9 cylinder engines and again, needed more work on cooling.

DH during the war improved the 6 cylinder engine by introducing reduction gearing and supercharger, perhaps based off the V-12? Also made the cylinders slightly bigger.

Lycoming killed the inline 6 market post war with the opposed 6 engines. It took a while, but it happened. Market forces (tariffs/taxes) also played a part.

Keeping high-powered air-cooled engines alive was always a trick and needing complicated air-flows/ducts and adjustments of flaps and louvers on what are supposed to be 'simple' engines is not going to be a long-term selling feature.

The market had passed the 500hp V-12 by.

 

[Shortround6]

meaning that it will never be choosen as a mainstream engine for the British.

Sort of, the British had gap in the power range offered by domestic engines.
A-S had the 300-340hp 7 cylinder Lynx engines and jumped to the 700hp + Puma (twin Lynx) and Napier was offering the 395hp H-16 Rapier and the 780-805hp H-24 cylinder Dagger III.
RR-Kestrel was being phased out.

One can warm-over the ww1 engine tech only for so much.

Not sure about that. Two valve heads, pushrods and air cooling seemed to work fairly well for American radial engines
Granted they changed an awful lot of other stuff in order to keep the "old tech" working.

One does wonder what Ranger and DH might have been able to do if they worked together on a clean sheet of paper engine?

 

[tomo pauk]

Granted they changed an awful lot of other stuff in order to keep the "old tech" working.

Bingo.

One does wonder what Ranger and DH might have been able to do if they worked together on a clean sheet of paper engine?

A 450 kg V12 that does 600 HP in a temperamental way with 87 oct fuel, with the price that is 90% of a Merlin, or 150% of a price of an interwar Mercury (in the case of RAF, just yank it from an obsolete fighter, making the Mercury free) that does same power with 80 oct fuel? As seen by the Ranger V-770.
I'd rather have the D-H make a Mercury- or Pegasus-based V8 - both cheaper and faster to make, and it will at least do some useful power.