USA produces a Mosquito-like bomber: pros and cons

[pattle]

So a civilization is to be judged by the sophistication of it's plumbing ??

I like the sarcasm in this comment, but joking aside this is often how ancient civilisations are judged when you think of the Roman ruins of Hadrian's Wall or the even older Minoan ruins of Festos and Knossos in Crete, so perhaps us modern peoples are not so advanced as we like to think.
Any way this thread is about an American Mosquito equivalent not Bren magazines or ancient lavatories, happy days.

 

[davparlr]

Nothing but we could do aerodynamics Mossie, Spit but what made the P51 was the Merlin.

Spit? With the same engine, the P-51 was 20 mph faster. Relative to the P-51, the Spitfire had poor aerodynamics.

What made the P51H were UK design standards not US

I am not sure that making an aircraft more fragile is a sign of advanced technology. This came back to bite the P-51H when the more robust P-51D was used in Korea, which was used in a more close support role.

If it wasn't the P51 wouldn't have needed the Merlin to make it the plane it became.

It took the airframe and the engine to be the P-51. The Spitfire with the Merlin engine did not have the speed or the fuel mileage to do the P-51 job.

The British were ahead of the USA as they recognised they needed an LMG and got the best they could without worrying about their ego and NIH issues. The 6pd wasn't a collaberation it was the best weapon of its time and the USA copied it.

Which I bet could be traced back to an operating system designed by Maxim or Lewis, both Americans.

The Lee Enfield which was close to but not as good as the Garrand,

I don't think close is right. There is significant firepower difference. The Garand is as far ahead of the Lee Enfield as the AK-47 is ahead of the Garand.

 

[SHOOTER]

I think that we did the right thing in avoiding the so called "Mosquito trap".
The Mosquito only worked because of all the other things going on at the time that made it insignificant in the over all scheme of things and thus not worth making it a major priority interceptor target.
Then there is the idea of using In Line LC engines instead of AC Radials. Why would you do this?
Lastly, I like your logo. The Mig-29 is one of the prettiest planes ever built.

 

[SHOOTER]

I say strategic because it cost them a lot of money and resources and left a hole in their plane mix that nothing really could fill.
If they had gone the Mossie route, then they would have had no need for the B-24 or the B-25 or the P-61 and so on, at considerable cost savings (in operational crews as well as in building them). The Mossy only worked because it's contribution to the war was so insignificant that the Germans never made them a high priority target for interception.

Plus, as said, this left operational holes, which they tried to fill by getting Mossies from the UK, but there was never enough to go around.
Obviously VLR PR and night fighters were 2, but there is the whole issue of how it limited their tactical bombing capability, in both the ETO and PTO.

The Mossy never had, or was used as a "Tactical Mission" bomber. Think Tiffy/P-47 ground attack missions. Why use a twin with two crew when a single with one will do a better job?

 

[SHOOTER]

I don't think the USA needed the Mosquito at all.Right on!

The first British-developed modern plane we adopted that I can think of was the B-57 Canberra, and we changed the cockpit to suit US tastes when we did that.Many other changes also. Almost a completely new plane when done. When the British got some F-4 Phantoms, they mandated British engines and came up with the Spey-powered variant. Look up it's history to see what a bad choice this was. I think it would be highly unlikely that the US would adopt any foreign aircraft during WWII, advisable thoiugh it might be.

I would point out that the Alison was a better engine than the Merlin with any set of "Fixes" to the myriad of problems in that the Allison was strangled by GM's refusal to institute the simple quick fixes shown to conclusively fix all the respective defects, as detailed in E. Schmued's book; "Mustang Designer", and when coupled to a turbocharger or a two stage blower could out power the Merlin at any point in history. Top Merlin power in actual service during WW-II was 1720 HP on 115-145 AV Gas, compared to 2220 HP to the Packard Merlin and 2,300 HP for the P-82's Alisons.

 

[SHOOTER]

Problem for the A-20 (and the Me 410) was that by 1944 the Mosquito bomber's max speed was 30 or 40mph faster than the proposed target.

I wonder how fast the F7F would have been if they redesigned the fuselage to carry bombs?

Most here forget that the placard speeds are not real world speeds in actual use. First, at night, they had to install flame dampers to prevent easy interception of the Mossy, which knocked off 12-16 MPH off of the placard speed. Or bulged bomb bay doors which knock off 4-7 MPH more, also depending on the model and throttle position used. There are many more items like various antennas, differences in EEW and Loaded weight that all slow the plane.
Secondly, you never see the speed when flown at Maximum Continuous Throttle position which is the true usable speed and very much lower than the number commonly shown in books, etc.

 

[wuzak]

I would point out that the Alison was a better engine than the Merlin with any set of "Fixes" to the myriad of problems in that the Allison was strangled by GM's refusal to institute the simple quick fixes shown to conclusively fix all the respective defects, as detailed in E. Schmued's book; "Mustang Designer", and when coupled to a turbocharger or a two stage blower could out power the Merlin at any point in history. Top Merlin power in actual service during WW-II was 1720 HP on 115-145 AV Gas, compared to 2220 HP to the Packard Merlin and 2,300 HP for the P-82's Alisons.

Not you again!

Merlin 66, 150 grade fuel, 2000hp 1944.
P-82 Allisons did not appear during WW2, nor did the P-82.
The Packard Merlin V-1650-9 (the one with 2200hp) was rated RM16SM - the same as some 100-series Merlins. About the only difference between the -9 and Rolls-Royce engines was that they use ADI to allow the boost to be raised from +25psi to +30psi.

Allison's 2 stage engines compared favourably with 2 stage Merlins - but they were somewhat later in timing.

Turbocharged Allisons - I think the best the P-38 got was 2000hp, and that was with ADI. Otherwise most, during the war, had WEP of 1750hp. Turbocharged engines also much heavier installations, and gave up significant exhaust thrust at altitude.

 

[wuzak]

The Mossy never had, or was used as a "Tactical Mission" bomber. Think Tiffy/P-47 ground attack missions. Why use a twin with two crew when a single with one will do a better job?

MOSQUITO FB.VI. Look it up.

 

[SHOOTER]

Uncle Sam's Spitfires had written a little-known chapter in US fighter history. Though the USAAF used over 600 Spitfires during the war, the aircraft was never given a US designation, and little publicity was given to the exploits of the 31st and 52nd Fighter Groups – nothing like what they would get in the summer of 1944 during the wild air battles over Ploesti when they flew Mustangs. This is most likely a good example of the US military's overall dislike of having to admit to using "NIH" (Not Invented Here) equipment.

During their time in Spitfires, the 31st FG claimed 194.5 confirmed, 39 probables and 124 damaged; the 52nd claimed 152.33 confirmed, 22 probables and 71 damaged. Thirteen pilots became aces on the Spitfire. Leland Molland went on to score another 6 victories in the summer of 1944 in the P-51 to bring his score to 11. Harrison Thyng added 5 more victories to his 5.5 as CO of the 4th FIW in Korea, while Royal N. Baker, who scored 3.5 in Spitfires added another 13 in Korea.

Source:http://spitfiresite.com/2010/04/uncle-sams-spitfires.html

I would reply that the 600 Spits ONLY produced 13 aces, or a little over 2% of the number of planes used. Or about 1/4 of the number of aces, 7.6% produced by a similar number of P-51s, P-47s, or P-38s.

 

[wuzak]

Most here forget that the placard speeds are not real world speeds in actual use. First, at night, they had to install flame dampers to prevent easy interception of the Mossy, which knocked off 12-16 MPH off of the placard speed.

Evidence?

Or bulged bomb bay doors which knock off 4-7 MPH more, also depending on the model and throttle position used.

Evidence?

also depending on the model and throttle position used. There are many more items like various antennas, differences in EEW and Loaded weight that all slow the plane.

What antennas?

Oboe was carried in the nose in Mosquitoes.

H2S required a radome in the rear fuselage - but I don't bellieve many Mosquitoes carried them.

The maximum eight of teh Mosquito went up from ~20,000lbs to ~25,000lbs, but they also gained a lot of power to make that possible.

Secondly, you never see the speed when flown at Maximum Continuous Throttle position which is the true usable speed and very much lower than the number commonly shown in books, etc.

This is the same for all aircraft. The maximum speeds are usually shown as the maximum WEP or combat speed.

 

[SHOOTER]

Light bombers typically operate below 15,000 feet performing CAS missions. I doubt turbocharging is the answer for such an aircraft.

But the Mossy was not used as a low altitude "Tactical bomber"! It was either low alt to small strategic targets, or high altitude at night which were the vast majority of their total sorties flown.
Exactly how many Mossy missions were flown in direct support of ground troops at the FEBA?

 

[fastmongrel]

Oh lordy not the red ink retard again. He has more sock puppets than I have empty beer bottles.

 

[SHOOTER]

My post; To make a long story short maybe the Mosquito is a fantastic aircraft that contributes in a mighty way towards to war effort but maybe it should only be built by the British and Commonwealth and shared with the Americans when needed or it makes sense.

I dispute that the Mosquito was a fantastic Aircraft, or that it made a mighty contribution. It was only successful because of the environment that they operated in. If it was restricted to solo type missions like low altitude, or day light bombing, with out the cover of the much more dangerous heavies that gave them cover, they would have been torn to bits. As it was, the vast majority of all Mossy missions were simply ignored in favor of using their meager assets to intercept the much easier and very much more dangerous heavy bombers with their huge bomb loads.

 

[SHOOTER]

Radials were actually quite efficient, with cruise sfcs of 0.38 to 0.43. Recall, that pre-ww2, most radials, at least in the US were being built for airlines, for which every pound of excess fuel is money out of their pocket. Had radials been as thirsty and inefficient as some here portray them, the airlines would not have used them.

Absolutely true! AC Radials only have high SFC at very high powers. Somebody do a Merlin at 1,720 HP take off power to see the true difference in fuel consumption.

 

[SHOOTER]

For a radial engined bomber to cruise on same speed as the inline-engined bomber, it must use more HP. Say, 1200 HP vs. 1000?Wrong, the difference in drag between a radial and inline in a bomber is very small. The fuselage and wing are very much larger fraction of the total frontal area than the nacelles. Think of this, the B-17 was more efficient than the Lancaster at the same weights, altitudes and speeds. The OP states US as a producer, and the USA was in position to build a V-12 powered bomber already in 1940, if they founded they need one.

This is a bad argument based on bad ideas that do not take most of the other variables into account. The thing I dislike most about all of these LC In lines Vs AC Radials is the utter failure to consider the Maintenance and Durability differences between the two types. The AC Radials are many times better than the LC In lines.

 

[SHOOTER]

If I am intruding stupidly will someone please just respond with a 'No' to this. Then i'll get my coat.No, you are wrong on this entire line of thought.

Since radial and inline are as much about cooling as anything else it seems appropriate to look for the answer to these riddles (why did de Haviland choose an inline engine? is such an engine esssential to the Mosquito concept?) in temperature. Specifically the temperature of the lubricant. That is to say, i think engine temperature would be a limit to the schnell bomber engine plan choice. On the other hand if air cooled engines can keep the lubricant within its temperature limits at the least favourable combination of speed, altitude and power demand then no such constraint on engine choice would apply.

To explain : elsewhere on the site I read that an increase in airspeed generally occurs with the cube root of the power.No, it is the square root of power, at least to over 450 MPH with prop planes. So to go from a 'standard' bomber design to a schnell bomber in this case might for example in 'fast cruise' be a matter of 305mph/276mph to the power of 3 - 1.35 that is to say we require 35% more power for 10% more speed, or at 'schnell escape' maximum speed possibly 405/276 3.15 times more power required for 46% more speed. Substitute more realistic number please if you will, i'm only illustrating a principle. The more power is produced the more heat must be removed - like 3 times as much. i believe that as temperature approaches the lubricant design limits, as shear stresses increase between moving parts and as 'hystersis' type mechanical flexing losses increase then power out vs power produced internally would be a worse than linear progression. So for a Schnell bomber on a mission more than 3 - possibly 4 or 5 times as much heat would have to be removed as for a conventional bomber on the same mission.No, the easiest way is to drastically reduce drag, not increase power, but the best of both worlds is to do both! Reduce drag and increase power at the same time.


I hope that makes sense - the implication would be that a US Mosquito will need a preferably Merlin in line liquid cooled engines for missions in Europe, but for long range missions in the Pacific - the schnell bomber concept may not work.

This argument all stemmed from looking at the V1710, V1650 and R 2600 specs on wikipedia - the stand out difference figure being kW/L or hp/cubic inch - specific power, youd need to explain why the SP for the radial was so much lower - my hunch was internal losses.

No, it was because the cooling system was so restricted on the air cooled engine. Hot spots in the head are very much harder to cool in the AC engine. But the Power/Weight figures do not include the weight of the cooling system in the LC Engine which are part of the AC Radial. If you look at the very much more significant figure of merit in Reciprocating engines, IE power per unit of piston crown area. The best AC Radials have ~.93 HP/Cm^2 of piston crown area! The best R-R made Merlin in service during the war was the 1720 HP mark which has 1.031 HP/Cm^2 of piston area. These numbers are the true differences in cooling ability difference between the two types. Turbo compounding makes the R-3350 1.091 HP/Cm^2. Far short of the post war Packard Merlin V-1650 and Alison V1710 at 1.25 HP/Cm^2 at 2,220 and 2,300 HP each. But the Napier Sabre and Nomad had all of these beat by a wide margin. For what it's worth.

 

[SHOOTER]

We might take a look at fuel consumption figures in order to approach closer to the answer, at least one of them. On maximum continuous power:
-R-2600-23: 145 US gals for 1275 HP at 11800 ft
-V-1650-1: 93 gals for 1010 HP at 16000 ft
-V-1710-39: 103 gals for 1000 HP at 15000 ft
-V-1710-49 (for P-38F): 100 gals for 1000 HP, from 0-27000 ft
-V-1710-89 (for P-38H): 115 gals for 1100 HP, from 0-26000 ft

On maximum power at lean mixture:
-R-2600-23: 70 gals for 855 HP at 18200 ft
-V-1650-1: 53 gals for 758 HP at 16000 ft
-V-1710-39: 45 gals for 600 HP at 15000 ft; V-1710-63: 58 gals for 760 HP at 12200 ft
-V-1710-49: 49 gals for 670 HP, from 0-30000 ft
-V-1710-89: 60 gals for 795 HP, from 0-30000 ft

Does not seem like the R-2600 have had anything above those in-lines as far as specific fuel consumption is the topic. It will use 0.11 gals to make 1 hp, vs. 0.092 for the Packard Merlin, and vs. 0.10 for the turbo V-1710 on max cont power. On max lean, 0.082, vs. 0.07, vs. 0.0755 for the turbo V-1710. The single stage V-1710 will consume 0.103 for max cont; 0.075 or 0.0763 for max lean.

Now before people say: the R-2600 will produce more power, so the plane will go faster - the quirk is that R-2600 was one of the draggiest engines in the ww2, and that will consume much of the excess power. It also has no exhaust thrust worth speaking about, since the exhausts were routed into collector pipes, the gases ejected downward in historic planes it powered. That should add some thrust to the props for the V-12s listed here (10%?). That, combined with extra drag of the radial, all but cancels any deficit in power, while the radial's extra consumption remains. More fuel calls for a bigger plane, that either slows it vs. a smaller, or calls for a more powerful engine, that consumes more, and so on - the weight spiral goes up.

All of the figures you post are plane specific which has nothing to do with the engine. As to that argument use the Mk-IX Spitfire's Fuel consumption figures Vs the P-51D to prove that point. Then use the Merlin powered Halifax Vs the B-17F. Then just to muddy the water use the Merlin powered Lanc Vs the same B-17F, but at Maximum Service Ceiling at the same over the ground speeds and take off weights to a range of 3,200 miles. The more variables we spec, the more meaningful the comparison becomes.

 

[SHOOTER]

The liquid-cooled V-12s in use during WW2 were primarily developed for military use; later civil uses were largely on extemporized transport aircraft, like the Lancastrian. Conversely, while the first US radials were developed at to a USN contract, they soon completely replaced liquid-cooled engines in the commercial arena, where reliability, long life, and efficiency were of paramount importance. Considering that cooling drag is a significant factor in any piston engined aircraft, if the drag of a well-designed radial installation was as much worse as some people here seem to believe, they would not have driven liquid-cooled engines out of the commercial market. The V-12s would likely have survived if they could demonstrate significantly better sfcs, and they could not do that, either: radials, in cruise conditions had sfcs of about 0.38 to about 0.4, which is about as good as a spark ignition engine can get.

I think the primary reasons that radials get dissed so often are that the V-12 aircraft looked more streamlined and faster (probably more because "streamlined design," as in Raymond Loewy, was fashionable) than radial-engined aircraft and the P-51, which was probably the cleanest piston-engined fighter to see service had a V-12. With the exception of the P-51, which had Cd,0​ about 15% below any other piston-engined fighter to see service, the demonstrated values of zero-lift drag (Cd,0​) for all piston-engined fighters clustered between about 0.021 and about 0.025 with no significant difference between V-12 and radial engined aircraft.

Great post with great facts and ideas!

 

[SHOOTER]

I'd take 'Mosquito-like' to mean:

Small (less than 20,000 lbs loaded);
Long-range (combat radius of greater than 600 miles);
Fast, particularly at higher altitudes (say, 360 mph plus);
Two-man;
Twin-engine;
Un-armed.

Overview[edit]

The Mosquito was a fast, twin-engined aircraft with shoulder-mounted wings.[57] The most produced variant, designated the FB Mk VI (Fighter-bomber Mark 6), was powered by two Merlin Mk 23 or Mk 25 engines driving three-bladed de Havilland hydromatic propellers. The typical fixed armament for an FB Mk VI was four Browning .303 machine guns and four 20 mm Hispano cannon while the offensive load consisted of up to 2,000 pounds (910 kg) of bombs, or eight RP-3 unguided rockets.[58]
Flight characteristics[edit]

The design was noted for having light and effective control surfaces which allowed for good manoeuvrability. It was noted that the rudder should not be used aggressively at high speeds, and the poor aileron control at low speeds when landing and taking off was also a problem for inexperienced crews.[86] For flying at low speeds, the flaps had to be set at 15°, speed reduced to 201 miles per hour (323 km/h) and rpm set to 2,650. The speed could be reduced to an acceptable 150 miles per hour (240 km/h) for low speed flying.[87] For cruising the maximum speed for obtaining maximum range was 200 miles per hour (320 km/h) at 17,000 lb (7,700 kg) weight.[87]
DH.98 Mosquito B Mk XVI[edit]

Mosquito P.R.34.

Data from Jane's Fighting Aircraft of World War II[160] and World War II Warbirds[163]

General characteristics
Crew: 2: pilot, bombardier/navigator
Length: 44 ft 6 in (13.57 m)
Wingspan: 54 ft 2 in (16.52 m)
Height: 17 ft 5 in (5.3 m)
Wing area: 454 ft2 (42.18 m2)
Empty weight: 14,300 lb (6,490 kg)
Loaded weight: 18,100 lb (8,210 kg)
Max. takeoff weight: 25,000 lb (11,000 kg)
Powerplant: 2 × Rolls-Royce Merlin 76/77 (left/right) liquid-cooled V12 engine, 1,710 hp (1,280 kW) each

Performance
Maximum speed: 361 kn (415 mph (668 km/h)) at 28,000 ft (8,500 m)
Range: 1,300 nmi (1,500 mi (2,400 km))with full weapons load
Service ceiling: 37,000 ft (11,000 m)
Rate of climb: 2,850 ft/min (14.5 m/s)
Wing loading: 39.9 lb/ft2 (195 kg/m2)
Power/mass: 0.189 hp/lb (311 W/kg)

Armament

Bombs: 4,000 pounds (1,800 kg) Only with bulged bomb bay doors which reduced top speed by 4-8 MPH.
The salient points are that the MTO is 25,000 pounds or more depending on the exact date of manufacture and that the cruising speed for maximum range is 200 MPH!

 

[wuzak]

All of the figures you post are plane specific which has nothing to do with the engine. As to that argument use the Mk-IX Spitfire's Fuel consumption figures Vs the P-51D to prove that point. Then use the Merlin powered Halifax Vs the B-17F. Then just to muddy the water use the Merlin powered Lanc Vs the same B-17F, but at Maximum Service Ceiling at the same over the ground speeds and take off weights to a range of 3,200 miles. The more variables we spec, the more meaningful the comparison becomes.

Actually they are engine parameters.

ie to produce 1275hp @ 11,800ft (critical altitude) the R-2600-23 required 145 USG per hour (I presume per hour, as without the time component it does not make sense).

An airframe specific fuel consumption would be in air miles per gallon (ampg), which combines the engine's performance (fuel consumption at specific power setting in gph) and the airframe performance (speed in mph at the same specific power setting).

Thus a Spitfire IX and P-51B Mustang using the same engine would have the same engine consumption (gph) but the latter would be faster at the same power setting, meaning that it would have a better ampg figure.