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

[Admiral Beez]

For a 1930s four-engined passenger/transport aircraft, the de Havilland DH.91 Albatross was quite small and lightweight compared to others of the type, such as the Focke-Wulf Fw 200 Condor, which had an almost identical span to the Albatross, but was substantially heavier. An upscaled Albatross with four RR Peregrine engines might have been interesting, more akin to a British Boeing 307.

As an aside, some good interior pics of this cutaway model Model of de Havilland DH.91 Albatross 'Frobisher' Aircraft | Science Museum Group Collection

 

[yulzari]

For a 1930s four-engined passenger/transport aircraft, the de Havilland DH.91 Albatross was quite small and lightweight compared to others of the type, such as the Focke-Wulf Fw 200 Condor, which had an almost identical span to the Albatross, but was substantially heavier. An upscaled Albatross with four RR Peregrine engines might have been interesting, more akin to a British Boeing 307.

As an aside, some good interior pics of this cutaway model Model of de Havilland DH.91 Albatross 'Frobisher' Aircraft | Science Museum Group Collection

I suspect that the DH91 Flamingo was built around the largest engines that De Havilland had in production which limited the gross weight.

 

[EwenS]

1936/37 saw significant changes in the DH design personnel and construction methods.

Arthur Hagg resigned from the company in early 1937 to pursue other interests on his own account firstly in yachting and then in consultancy work with D Napier & Son Ltd. His final DH projects being the DH 88 Comet Racer and then DH 91 Albatross and DH 93 Don trainer both of which flew for the first time in mid-1937. All were of wooden construction. His work with Napiers began with the wooden Napier-Heston Racer, a single seat monoplane racing aircraft that finally flew in mid-1940. His interests clearly lay in the design of wooden craft for air & Sea.

His replacement in the role was R E Bishop, who had worked for the company since 1921. He was appointed chief designer in late 1936. The first DH aircraft he wasHe fully responsible for was the DH 95 Flamingo. This marked a significant change of direction for the company with that aircraft being its first all-metal stressed skin aircraft. It flew in Dec 1938.

While Bishop oversaw design of the wooden DH 98 Mosquito and the part wood / part metal DH 100 Vampire and DH 102 Hornet, post-war he went on to head the design teams for the various metal DH airliners and other aircraft into the 1960s.

 

[MikeMeech]

Hi
The DH.91 Albatross was powered by four de Havilland Gipsy Twelve series I engines of 525 hp each.

The DH.95 Flamingo was powered by two 890 hp Bristol Perseus XIIC or 930 hp Perseus XVI engines.

Mike

 

[Shortround6]

For a 1930s four-engined passenger/transport aircraft, the de Havilland DH.91 Albatross was quite small and lightweight compared to others of the type, such as the Focke-Wulf Fw 200 Condor, which had an almost identical span to the Albatross, but was substantially heavier.

What is the point of a four-engine transport?
By that I mean why use 4 engines instead of 3 or two engines?
Does the four-engine transport carry more passengers per flight?
Will the four-engine transport carry the same number of passengers further?
Will the four-engine transport carry the same number of passengers significantly faster?

The Albatross was beautiful. As an actual transport it was just OK, not good and not a basis for scaling up.
One problem was the engines. Needing 4 engines to get 2100hp and paying over 4000lbs for that power was not going to work well.
Fw 200 prototype had 3500hp. It may not have been any faster (?) than the Albatross but it could carry a few more passengers much further.
The Albatross does not stand up to comparison with the DC-3. A 1938 DC-3 will carry about the same number of passengers at about the same speed and carry them about as far.
It did it with two engines (with more power) with an airplane that was about 3000lbs lighter empty and over 4000lbs lighter at full load.
There was a reason that the DC-3 was such a success. It worked and worked well. It could transport passengers a decent distance at a decent speed with the lowest cost per passenger mile. And it could do it safely. An Albatross could stay in air with one engine out and 3 running. The DC-3 could stay in the air with one engine running. Depending on propeller fitted it fly either a few thousand feet lower than the 3 engine Albatross or a few thousand feet higher.

 

[Admiral Beez]

What is the point of a four-engine transport?

This....

It could transport passengers a decent distance at a decent speed with the lowest cost per passenger mile. And it could do it safely.

Could an enlarged Albatross, presumably called the Royal Albatross after the (2nd) largest of that species, with four Peregrine engines exceed the two-engined capabilities of the DC-3?

 

[tomo pauk]

What is the point of a four-engine transport?
By that I mean why use 4 engines instead of 3 or two engines?
Does the four-engine transport carry more passengers per flight?
Will the four-engine transport carry the same number of passengers further?
Will the four-engine transport carry the same number of passengers significantly faster?

A good 4-engined transport might've been good for the trans-Atlantic route.

The Albatross was beautiful. As an actual transport it was just OK, not good and not a basis for scaling up.
One problem was the engines. Needing 4 engines to get 2100hp and paying over 4000lbs for that power was not going to work well.
Fw 200 prototype had 3500hp. It may not have been any faster (?) than the Albatross but it could carry a few more passengers much further.
The Albatross does not stand up to comparison with the DC-3. A 1938 DC-3 will carry about the same number of passengers at about the same speed and carry them about as far.
It did it with two engines (with more power) with an airplane that was about 3000lbs lighter empty and over 4000lbs lighter at full load.

I'd say that engines were The Problem.
While we can understand the D-H decision to go with the in-house engines and propellers, the Gypsies were a bad choice. Of too low horsepower, Albatros needed 4 of them to matter. 4 Gypsies were too heavy a powerplant. Modding the aircraft to be powered by just two Pegasus engines would've yielded them a much more attarctive aircraft from the standpoint of an eventual buyer, being lighter and cheaper to buy and operate. Or, going with 4 Mecuries would've added heavps of power for a miniscule in weight, and as such it would've been attarctive as a military aircraft, where the engine-out situation does not mean that the rapid retreat to a base is necessary.

 

[cammerjeff]

What is the point of a four-engine transport?
By that I mean why use 4 engines instead of 3 or two engines?
Does the four-engine transport carry more passengers per flight?
Will the four-engine transport carry the same number of passengers further?
Will the four-engine transport carry the same number of passengers significantly faster?

The Albatross was beautiful. As an actual transport it was just OK, not good and not a basis for scaling up.
One problem was the engines. Needing 4 engines to get 2100hp and paying over 4000lbs for that power was not going to work well.
Fw 200 prototype had 3500hp. It may not have been any faster (?) than the Albatross but it could carry a few more passengers much further.
The Albatross does not stand up to comparison with the DC-3. A 1938 DC-3 will carry about the same number of passengers at about the same speed and carry them about as far.
It did it with two engines (with more power) with an airplane that was about 3000lbs lighter empty and over 4000lbs lighter at full load.
There was a reason that the DC-3 was such a success. It worked and worked well. It could transport passengers a decent distance at a decent speed with the lowest cost per passenger mile. And it could do it safely. An Albatross could stay in air with one engine out and 3 running. The DC-3 could stay in the air with one engine running. Depending on propeller fitted it fly either a few thousand feet lower than the 3 engine Albatross or a few thousand feet higher.

A 4 engine transport does not have to be over powered like a 2 engine transport does for safety reasons, the example being when a plane loses an engine at the worst possible time just after lift off, a 4 engine plane only loses 1/4 of it available power, a twin engine aircraft loses 1/2 it available power. This causes a twin engine aircraft to be over powered requiring more powerful engines to be used.
On the other side the 4 smaller engines may be more expensive to purchase, and will almost always be more expensive from a fuel and Maintenance stand point. I am not a structural engineer so I can not speak to any added weight either design would require, a lesser powered engine does not require as strong of a mount or structure to secure it. But the drag will most likely be higher.
Then you have to consider that if the airframe builder has an in house supplier of engines, in this case DH did (like Junkers and Curtis-Wright did) and those builders tended to favor the use of in house engines when ever possible. So in this case DH used the largest DH built engines available for the design, and it required 4 of those engines to achieve the desired performance. You also have to consider the economic times, coming out of the depression, it was very attractive to use engines made by your company to help keep production going in that part of your business.

So like every thing else in aviation it is a series of compromises to achieve the desired results, was it the correct decision? The results were successful, did the project make a profit for DH? Did it keep both the engine and airframe sections of the company viable for the future? Without the project would engineers and production workers have to be laid off? And if so how would those layoff have effected future projects or the company as a whole? Interesting to think about, but above my pay grade to answer.

 

[tomo pauk]

A 4 engine transport does not have to be over powered like a 2 engine transport does for safety reasons, the example being when a plane loses an engine at the worst possible time just after lift off, a 4 engine plane only loses 1/4 of it available power, a twin engine aircraft loses 1/2 it available power. This causes a twin engine aircraft to be over powered requiring more powerful engines to be used.

On the other side the 4 smaller engines may be more expensive to purchase, and will almost always be more expensive from a fuel and Maintenance stand point. I am not a structural engineer so I can not speak to any added weight either design would require, a lesser powered engine does not require as strong of a mount or structure to secure it. But the drag will most likely be higher.

Agreed all the way.
If a 4-engined aircraft does not 'buy' you a considerable leap in aircraft's capabilities, the 2-engined competition will burry it in the market, both the civilian and military.

Then you have to consider that if the airframe builder has an in house supplier of engines, in this case DH did (like Junkers and Curtis-Wright did) and those builders tended to favor the use of in house engines when ever possible. So in this case DH used the largest DH built engines available for the design, and it required 4 of those engines to achieve the desired performance. You also have to consider the economic times, coming out of the depression, it was very attractive to use engines made by your company to help keep production going in that part of your business.

I've already noted that it is only to be expected that the in-house stuff is a preferred choice form the manufacturer.
However, it is a buyer that calls the shots, not the manufacturer. Once you basically build-in the weak heart in a machine just because you make only weak hearts, the flop in the market is only to be expected.
Curtiss burned their fingers with the 1st prototype of the future P-36, they have read the room after that, installed the competitor's engine, and thus produced a success.

We also have a thing where D-H was perhaps 3rd league between the British engine makers of modern engines, while both Curtiss(-Wright) and Junkers were top tier engine makers in the respective countries.

So like every thing else in aviation it is a series of compromises to achieve the desired results, was it the correct decision? The results were successful, did the project make a profit for DH? Did it keep both the engine and airframe sections of the company viable for the future? Without the project would engineers and production workers have to be laid off? And if so how would those layoff have effected future projects or the company as a whole? Interesting to think about, but above my pay grade to answer.

Well, I'm not one to be shy, ever

I'm not sure that either the V12 Gypsies nor the Albators was a commercial success, but probably the contrary.
Albatros probably gave the confidence to the company to conclude that a workable and fast aircraft can be made despite using a lot of wood and sparse metal - if that was the case, perhaps Mosquito owns a lot to the Albatros.
As for the company and engineers - British needed both of them come the late 1930s, so I'd not be worried a lot there.

 

[Shortround6]

This....

Could an enlarged Albatross, presumably called the Royal Albatross after the (2nd) largest of that species, with four Peregrine engines exceed the two-engined capabilities of the DC-3?

Quite possibly.
Trouble is it would not be competing with a DC-3 in original form. DC-3s used both Wright and P&W engines and went through several different engines of each type. Numbers I have used are for the 1937-38 versions.
Yanking the DH-Gypsy King engines and replacing them with Peregrines means that you have added the weight of the liquid cooling system/s and you need larger/heavier propellers.
Albatross already weighed 21,300lbs empty. Gross max weight was 29,500lbs. Maybe you can increase the gross weight without beefing up the landing gear and/or structure but increasing the power by over 50% is going to push some loads to the max or beyond.
Airliners did not have the same head room for G loads that bombers did let alone fighters. G loads also included the landing gear impact loads and loads in other aspects of flight (negative G loads in a wind gust).
Number of smaller planes traded higher power engines for less payload for shorter take-off runs, higher cruising speeds or better ability to handle mountain ranges. Some did beef up the structure to take full advantage of the extra power (higher payload).

As for the DC-3. they got somewhat (100-200hp) more powerful engines.

In the US Boeing was planning on a 4 engine airliner (B-17 wings), Douglas built the DC-4E (too big and sold to Japan) and Curtiss was building the CW-20 which later turned into the C-46 with a change in tail and change in engines.

original estimates, 23,090lbs empty, 36,000lbs loaded. Engines were either 1500hp or 1600hp for take-off and 1350hp max cruise.
30 passengers, 200mph cruise at 10,000ft. range not given.

Paying for a heavier, more expensive (4 liquid cooled engines and larger props) Albatross means you have to carry more passengers to pay for it and to pay for the higher operating expenses.

 

[Shortround6]

A 4 engine transport does not have to be over powered like a 2 engine transport does for safety reasons, the example being when a plane loses an engine at the worst possible time just after lift off, a 4 engine plane only loses 1/4 of it available power, a twin engine aircraft loses 1/2 it available power. This causes a twin engine aircraft to be over powered requiring more powerful engines to be used.

In the 1930s there were several other things going on and sometimes the 4 engined aircraft gave an illusion of safety.

1933 (?) with fixed pitch props. Not too bad because cruise speed was only about twice take-off speed. Airliner with a cruise speed 3 times take off speed is either throttling back the engines or operating in a bad pitch range (low thrust for power). Of course using 4 engines for reliability when you are using Armstrong-Siddeley 10 cylinder two row radials might have been a very wise decision Sparkplugs and valve springs got a lot better from 1930 to 1937-38.
Trying to fly a 20,000lb plane with 1320hp in tropical conditions was also a little dubious.
Also note the vertical fin and rudder. In an engine out situation stability and rudder control is important. It took a while for this to sink in. A-20s got a larger fin and rudder went they went to the 1600hp engines but there had been complaints about the handling of 1200hp versions with an engine failure. B-26s also got larger fin and rudder.
With more reliable engines, constant speed propellers and more rudder authority twin engine planes could be very close to the safety of a 4 engine plane.
Larger fin and rudder does have more drag but using 4 engines also has drag problems.

It turns out that DC-3s and especially C-47s were flown at slower speeds than originally for less fuel burn, this often meant that they were operating at 50-65% power. perhaps they were overpowered but they had the extra power for either engine out situations or for bad weather. Hot and high or storms/icing. The US adoption of fulling feathering propellers
was a major safety benefit. The feathered propeller caused much less drag and needed less rudder deflection to keep the plane flying straight.

Having extra power available if needed is usually good. The Commercial Wright and P-W engines usually had very good overhaul lives so the cost was spread out.

 

[Howard Gibson]

For a 1930s four-engined passenger/transport aircraft, the de Havilland DH.91 Albatross was quite small and lightweight compared to others of the type, such as the Focke-Wulf Fw 200 Condor, which had an almost identical span to the Albatross, but was substantially heavier. An upscaled Albatross with four RR Peregrine engines might have been interesting, more akin to a British Boeing 307.

As an aside, some good interior pics of this cutaway model Model of de Havilland DH.91 Albatross 'Frobisher' Aircraft | Science Museum Group Collection

The DH Albatross was similar in capacity, speed and range to a Douglas DC3. I understand the British had a different philosophy when it came to multiple engines. In an American twin, when an engine conks out, you land at a convenient airfield and fix it. In a British four, you are way out in the middle of nowhere, and you continue flying to your destination.

The Albatross was powered by de Havilland Gipsy Twelves. Perhaps this was the biggest engine manufactured by de Havilland?

Look up the Armstrong Whitworth Ensign. The British were building big airliners prior to the war. Interestingly, they used Wright R1820s.

 

[Admiral Beez]

The Albatross was powered by de Havilland Gipsy Twelves. Perhaps this was the biggest engine manufactured by de Havilland?

At 18.4 L, it's definitely one of the largest air cooled V-12s used in any aircraft. There is the 20 L Lycoming O-1230, but that's a flat 12.

 

[Shortround6]

The DH Albatross was similar in capacity, speed and range to a Douglas DC3. I understand the British had a different philosophy when it came to multiple engines. In an American twin, when an engine conks out, you land at a convenient airfield and fix it. In a British four, you are way out in the middle of nowhere, and you continue flying to your destination.

Americans were fond of tri-motors in the 20s and early 30s in order to handle engine out situation.
But design philosophy changed over the years due to changes in technology, higher power to weight engines, better propellers, better construction and airfoils/flaps.
A lot of the US did have convenient airfields, but as you go west things get a lot less convenient, much like western Canada. Difference is mainly population density (member of flights)
and the wider distances of the mountain ranges in the US. Canadian mountains could be higher but most of the time the Canadian pilots didn't have to fly scheduled air routes over them. Vancouver being the only sizable city west of Calgary?
Regardless the plane has to be able to maintain height over terrain they were flying over, using the engines and propellers they had at the time which changed almost by the year in 1930s. Maintaining safe height with a dead engine has a number of factors.

The Albatross was powered by de Havilland Gipsy Twelves. Perhaps this was the biggest engine manufactured by de Havilland?

This was the largest engine built by DH. But it did limit the potential of the design.

Look up the Armstrong Whitworth Ensign. The British were building big airliners prior to the war. Interestingly, they used Wright R1820s.

The Ensign was a poster child of British aviation tardiness.
The Wright R-1820s were the third choice of engine for the plane and that was around 5-6 years after start of design?
The Ensign started design in 1934 but work on the Whitley and changes by the customer delayed first flight until 1938 by which time the airframe was dated, the engines were also dated and the props on the prototype were also dated, changed very quickly.
The short take-off and landing distance requirement helped dictate the very large wing with the limited power of 1934-35 engines. But a 2450 sq ft wing was going to heavy and high drag. A-S screwed themselves using their own Tiger engine which may have been a decent choice in the 1920s or even 1934-35 but it seems to have fallen behind after that. What was acceptable performance in 1934-35 not only in power but in reliability was no longer acceptable in 1938. The Tiger powered the first 12 Ensign airliners before they switched to the R-1820 for the last two. The eight surviving MK Is were repowered during 1941-43 but by that the time the R-1820 engines they were using were not the latest version and I am not sure of the propellers they were using.
You need more than the "concept", you need the ability to bring the concept to market/service in less than 4-5 years or you are competing with "newer" aircraft.
1-2 years was a lifetime in mid 1930s.

 

[Shortround6]

At 18.4 L, it's definitely one of the largest air cooled V-12s used in any aircraft. There is the 20 L Lycoming O-1230, but that's a flat 12.

Renault 12R engine 19.0 liters. 500hp
Isotta-Fraschini Gama 19.2 liters 580hp (?)
Isotta-Fraschini Delta 26.7 liters 750hp (?)

Lycoming 0-1230 was liquid cooled and had a relation to only one other engine in the Lycoming 'catalogue'.
The XH-2470 24 cylinder engine.
No relation to the Lycoming air cooled engine family at all.

 

[yulzari]

Going off on an AH tangent, if the Gipsy Queen development is a guide (and yes I do know I am using post war data) as half of a Gipsy Twelve then the Gipsy Twelve could have ended up at @660bhp with a modest increase in weight. So we are looking at the same power for the airframe as the DC3 but with more weight.

It emphasises that the decision to use the Gipsy Twelve made commercial sense to De Havilland profits but would hamper worldwide sales numbers. Á larger DH91 would mean bought in engines.

 

[tomo pauk]

It emphasises that the decision to use the Gipsy Twelve made commercial sense to De Havilland profits but would hamper worldwide sales numbers.

That decision hampered not just the sales that would've happened abroad, but also the sales in the UK proper. IOW - the decision made no commercial sense.

Á larger DH91 would mean bought in engines.

The end customer is the king - my 30+ years in sales thaught me that, out of that 20 that I'm my own boss - and he (or more of them) will also pay for the bought-in engines.

 

[Shortround6]

Going off on an AH tangent, if the Gipsy Queen development is a guide (and yes I do know I am using post war data) as half of a Gipsy Twelve then the Gipsy Twelve could have ended up at @660bhp with a modest increase in weight. So we are looking at the same power for the airframe as the DC3 but with more weight.

It emphasises that the decision to use the Gipsy Twelve made commercial sense to De Havilland profits but would hamper worldwide sales numbers. Á larger DH91 would mean bought in engines.

Not sure it would have reached 660hp before WW II. Perhaps 575-600hp on 87 octane?
DH did a pretty good job with the Albatross but Douglas had really shifted the landscape.
Comparing the Albatross shows late 30s French 3 and 4 engine airliners were comparable in installed power and size/weight and speed.
See Bloch 160 4 engine aircraft. a bit larger and with a bit more power (720hp each).
It was stretched to the MB 161 using G-R 14N engines and around a 40% increase in weight but the war interrupted things.

After Douglas went to the "wide body" DC-3 and revolutionized air transport economics it took a while for everyone else to catch up.
Lockheed tried going for speed with model 14 and 18 but the model numbers tell the story (14 and 18 passengers) compared to 21-28 for the DC-3 using the same engines means that they weren't as profitable, despite the higher speeds.

For the Albatross we don't know the structure weight and if it could be scaled up easily. DH did a very good job with wood but wood requires more weight than aluminum. Trying to build large wooden planes meant there was often a penalty.

 

[Shortround6]

That decision hampered not just the sales that would've happened abroad, but also the sales in the UK proper. IOW - the decision made no commercial sense.

I am not sure that any large British airliner of the 1930s ever actually made money for the company that built them.
There were 23 different designs including the DH Dragons and Dragon Rapides, and only 4 designs were built numbers exceeding 22 planes.
DH made money with the Dragon (202 built) and 6-10 passengers and the Dragon Rapide (227?)
Perhaps the major manufactures shifted to military contracts in the mid to late 30s?
Only Short and DH seemed to actually construct airliners in the late 30s.
Short built 42 of the Empire flying boats which was the largest production run and largest airliner production operation for British airliners.

Trying to scale up the Albatross to significantly add power, fuel and passengers with the wooden airframe wooden might have been difficult.
A number of WW II wooden aircraft did not turn out very well. The Mosquito was a notable exception.

 

[cammerjeff]

And I think we are forgetting that the DH Albatross was originally designed to be a trans Atlantic Mail carrier, I don't know if carry passengers was really considered for the original design. I dont think DH planned on selling a great many of that design considering it was designed for long range and high cruise speed, with a very limited payload.

To me it made perfect sense to use in house engines to increase profits (or reduce losses?) on such a design with limited sales potential.