USA produces a Mosquito-like bomber: pros and cons (1 Viewer)

[SHOOTER]

Yep, wait for 20+ years to have a bomber with lower performance than the Mosquito.

Apart from the length of the Mk 84 bomb, two could fit inside the Mosquito's bomb bay.

Since the highly streamlined bomb was well in hand during WW-I, not to mention the tallboy and grand slam of WW-II, this seems like a very easy way to go!

 

[wuzak]

1370 mile range was with 2 500lb bombs under the wings. Thus only internal fuel was available. The maximum internal fuel for a B.XVI was 536 UK gallons, but with the 5000lb bomb load only 500 UKG was used for the 1370 mile range. Perhaps because of MTO weight considerations.

For maximum fuel (536 UKG internal plus 2 x 50 UKG in drop tanks) the range was 1795 miles with 2000lb bomb load.

 

[wuzak]

Since the highly streamlined bomb was well in hand during WW-I, not to mention the tallboy and grand slam of WW-II, this seems like a very easy way to go!

External bombs and carriers still create more drag than internal bombs. Plus the P-38 couldn't then use the drop tanks for extended range.

 

[wuzak]

Where did you get this number. I ask because it seems very high to me. I get 68 GPH for one engine, is that for two engines? With what prop in what plane was it measured?

I got the number from Tomo's post which you quoted.

I doubt that it was measured on an aircraft. It was, most probably, measured in the test cell.

True, if they were the same engine, but the Packard Merlin and R-R Merlin were not the same engines. They were similar, but not the same.

There were small differences between the Packard Merlin and the Rolls-Royce Merlin. Notably the Packard engines had an epicyclic gear train (designed by Wright) to drive the supercharger, whereas the Rolls-Royce Merlin used the Farman type gear set.

 

[SHOOTER]

The P-82 with Allisons was a post WW2 aircraftTrue. while AFAIK the Packard Merlin V-1650-7 used in production P-51s generated a maximum of 1,860 hp on 100/150 grade avgasNews to me, I thought it was 1,595 HP? But it does not change anything.

http://www.wwiiaircraftperformance.org/150grade/engcleared-matcom-b.jpg
http://www.wwiiaircraftperformance.org/150grade/44-1_Fuel-16March44.pdf

The Merlin 66 used in Spitfire L.F Mk IXs generated 2,000 hp on 100/150 grade avgas:I did not know that! Honestly, it is news to me. Everything I've read stated 1,720 HP and then only in short life engines. See the relevant pages in Janes, both during and post war.

The only figures that I've ever seen printed in books that show more than 2000 HP are for the post war Hornets at 2,050/2,080 HP depending on the model. I then compare that the P-51H's 2,220HP which was an "in service" late war time, production engine with a 1000 hour TBO, not approached by the post war Hornets.
The second part of the argument is that the Two stage Alison was a terrible engine WO the "fixes" inlet backfire screens, etc. Read Edgar Schmued's book "Mustang Designer" in which he details the effects of the fixes they installed WO Alison approval to prove the problems were not with the plane, but all Alison-GM's! Note that the extra power, 2,300 to 2,220 HP, provided by the Alison engine made the much heavier and huge pod equipped night fighter almost as fast as the A-B models WO the pod!

 

[wuzak]

Wire radio and it's mast.

These were basically the same over all versions - so why would they make a difference in performance between marks?

Here's one more of the many.

Huh?

And that changes my point how? Did they have MTOs of 25,000 pounds or not?

Some did, some did not.

B.XVI, PR.XVI did. B.IV, FB.VI did not.

You are right! WEP is not real world speed and is only used to evade, or enable a shoot down, not prevent the interception in the first place. Real world speed is maximum continuous that will permit the mission range to be flown! In some cases that is only 200-220 MPH for long range with heavy loads.

I doubt that any mission was performed with aircraft flying at the same speed throughout.

Missions were generally planned around the aircraft - how far they could fly, or how much load could they carry to get the distance.

 

[wuzak]

The only figures that I've ever seen printed in books that show more than 2000 HP are for the post war Hornets at 2,050/2,080 HP depending on the model. I then compare that the P-51H's 2,220HP which was an "in service" late war time, production engine with a 1000 hour TBO, not approached by the post war Hornets.

Merlin 66, 100/130 grade fuel.
MS Gear: 1750hp, 3000rpm, +18psi boost, 5250ft.
FS Gear: 1625hp, 3000rpm, +18psi boost, 12,500ft.

Merlin 66, 100/150 grade fuel.
MS Gear: 2000hp, 3000rpm, +25psi boost, 5250ft.
FS Gear: 1860hp, 3000rpm, +25psi boost, 11,000ft.


Merlin 76/77, 100/130 grade fuel.
MS Gear: 1700hp, 3000rpm, +18psi boost, 10,500ft.
FS Gear: 1475hp, 3000rpm, +18psi boost, 22,500ft.

Merlin 76/77, 100/150 grade fuel.
FS Gear: 1940hp, 3000rpm, +25psi boost, 5500ft.

Data from Lumsden.

What is your source for TBOs?

In 1943 Rolls-Royce ran a Merlin 66 for 100 hours continuously, having strengethened components after previous tests, at +18psi and 3000rpm. This became the basis of 100 series Merlines - including the V-1650-9.

 

[wuzak]

First I've heard about the 30 pound boost used, source please.

Data at war emergency rating with water injection at 3000 rpm.

Altitude Ft.	TAS     MP             Throttle
                MPH    "Hg    Blower   Setting
S.L.            401     90	Low	Part   
*6800           431     90	Low	W. O.
**13400         423     90	High	Part   
***21200        451     90	High	W. O.
25000           448     78	High	W. O.

* Low Blower Critical Altitude for 90" Hg., MP
** Altitude for Blower Shift.
*** High Blower Critical Altitude for 90" Hg., MP.

P-51H Performance Test

90" Hg = +30psi boost.

 

[wuzak]

V-1650-7 Engine Performance Data (Static)
R.D.E.1.(a) 1/9/44
Combat Conditions

3000 r.p.m. + 25 lbs/sq.in. B.H.P. at S.L. = 1940
Max. power in "M.S." gear = 1940 B.H.P. at S.L.
Max. power in "F.S." gear = 1810 B.H.P. at 12,000 ft.
Supercharger change height = 5,000 ft.

3000 r.p.m. at 67" Hg. boost pressure. B.H.P. at S.L. = 1630
Max. power in "M.S." gear = 1,700 B.H.P. at 5,750 ft.
Max. power in "F.S." gear = 1,555 B.H.P. at 17,750 ft.
Supercharger change height = 10,500 ft.

3000 r.p.m. + 61" Hg. boost pressure. B.H.P. at S.L. = 1490
Max. power in "M.S." gear = 1580 B.H.P. at 8,500 ft.
Max. power in "F.S." gear = 1400 B.H.P. at 21,000 ft.
Supercharger change height = 13,400 ft.

Climb and cruise

2,700 r.p.m. + 46" Hg. boost pressure. B.H.P. at S.L. = 1050
Max. power in "M.S." gear = 1150 B.H.P. at 11,250 ft.
Max. power in "F.S." gear = 1080 B.H.P. at 22,000 ft.
Supercharger change height = 14,250 ft.

Weak mixture cruise

2,400 r.p.m. + 36" Hg. boost pressure. B.H.P. at S.L. = 730
Max. power in "M.S." gear = 820 B.H.P. at 13,000 ft.
Max. power in "F.S." gear = 755 B.H.P. at 22,500 ft.
Supercharger change height = 16,250 ft.

P-51 Mustang Performance

Note that 67" Hg = +18psi boost
81"Hg = +25psi boost

 

[SHOOTER]

I don't like AK's and I do like Garand's, Actually I like HK940's but that is another topic. Even though I am not an AK fan the difference in firepower between an Garand and an AK is more then small. The Garand is more accurate, has better range, has more power but does not have more firepower.
One definition of "Fire Power" is hits per unit of time. Using this measure the Garand is three to four times as effective as the AK-47. While many folks make much out of the AK's full auto power, they have not actually used it. It is next to impossible to hit anything with a full auto AK-47. This is why the Reds went to the AK-74!
On the Lee-Enfield, I don't think the Garand is 4 times better. Use the above measure. I think four guys armed with an Enfield can put more fire down range than one guy with a Garand. Only if you only count shots fired, not hits. A Lee-Enfield requires two complete actions to load ten rounds from two five round stripper clips. Then each shot must have the bolt worked between shots. A Garand can be loaded with eight rounds in much less time than it takes to load a single stripper clip of five rounds, not counting the time to close the bolt. Loading the Garand is a single motion deal with the bolt closing with out action by the shooter. One soldier can fire more aimed shots than four Enfield guys in one minute. Enfield is more reliable, with a couple of small tweaks is more accurate. The Enfield is one of the fastest bolt guns to be mass produced.

As to accuracy, the Garand is required to pass a 2.5 MOA test before acceptance into service. A feat that most "Tweaked" Enfields can not match. Major service conditioning, similar to what we call the "National Match", or Sniper rifle Mods, yields a a 1.6 MOA rifle with service ammo and a 1.25 MOA rifle with the 172 grain sniper ammo. This from WW-II testing and acceptance trials. I've seen WW-II issue Enfields with perfect and bright bores that could not shoot 6.6 MOA groups with service ammo. They had loose bolts, but were as new condition still in the wrapper. I have seen others that would shoot under 3 MOA, but they were very few and far between. IIRC, the Enfield Service acceptance standard was 5 MOA by the trained soldier?
I remember an old saying that went sort of like this; The Germans build rifles to parade with, the Americans build rifles to shoot targets with and the English build rifles to fight wars with. This in reference to bolt action rifles. This was in reference to the fact the German's rifles were shinny and the Americans were the most accurate, but the Enfield's the fastest firing. The Enfield's problem was the rear lugged bolt which was used to get around the Mauser Patents. This made fitting the bolt in both the right face space and alignment almost impossible in a production gun. In addition the bolt had substantial flexion when fired. While a master gunsmith could take selected rifles with the right bolt fitment and turn them into a decent sniper rifle, the Ruski's thought their Myosin Nagant and Dragenofs were great too. Until they had to fire a long range match Vs the M-14NM/21, M-16, M24/40, all sub-MOA, all the time.
As an aside, if you, or any other member of this board ever get to this part of the world, come by and I'll take you shooting with all eight of my battle-sniper rifles. Two M-14s, a DPMS LR-308, A Remington 700 SSFS in .300RUM, a Savage 112M in 22-250, A 4 in .224 Clark Imp, two R-742s in .308 and a Ruger 10-22S, I also have four Para P-14 Ltds, a Barlow Custom P-14 Ltd with a 6" Nolan slide and ten port comp, a P-13, a P-12, A .45 Firestar, A Rem-51, HS-Citation/Olympic, half a dozen .25 Brownings, a 1910 and two 1910/22 Brownings, A scoped Ruger 10-22 pistol, a Glock-17, two Grendel P-30s, Rem 11-87 Master Blaster, and a dozen more I can't think of right now. You can shoot as much as you like as long as you buy your ammo.

 

[SHOOTER]

1370 mile range was with 2 500lb bombs under the wings. Thus only internal fuel was available. The maximum internal fuel for a B.XVI was 536 UK gallons, but with the 5000lb bomb load only 500 UKG was used for the 1370 mile range. Perhaps because of MTO weight considerations.

For maximum fuel (536 UKG internal plus 2 x 50 UKG in drop tanks) the range was 1795 miles with 2000lb bomb load.

Just a question since Wiki lists the total available fuel as 615-715 gallons, including 2X50, or 2X100 gallon drop tanks making 515 gallons internal fuel. But I suppose that there were many variations between the first and last of any given type? The source I found gives the 1795 mile range with two 100 gallon drop tanks, but did not spec the internal fuel load. But again, it's on the internet, so it must be right? Sarcasm X 2! I would like to see a post war pilots manual with flight planning data.

 

[SHOOTER]

External bombs and carriers still create more drag than internal bombs. Plus the P-38 couldn't then use the drop tanks for extended range.

The late model P-38 had four hard points on the wings and bombs could go on the outer ones, or vice verse.

 

[SHOOTER]

These were basically the same over all versions - so why would they make a difference in performance between marks?
Different radios required different antenna matching sets and longer or shorter wires and higher or lower masts. The different equipment weights causes more or less induced drag


I doubt that any mission was performed with aircraft flying at the same speed throughout.That is an absolute fact! The plane's speed changes as the fuel is burned off. Even more so if the reduced weight is used to buy more altitude with a turbo'd plane.

Missions were generally planned around the aircraft - how far they could fly, or how much load could they carry to get the distance.

All true!

 

[SHOOTER]

Merlin 66, 100/130 grade fuel.
MS Gear: 1750hp, 3000rpm, +18psi boost, 5250ft.
FS Gear: 1625hp, 3000rpm, +18psi boost, 12,500ft.

Merlin 66, 100/150 grade fuel.
MS Gear: 2000hp, 3000rpm, +25psi boost, 5250ft.
FS Gear: 1860hp, 3000rpm, +25psi boost, 11,000ft.


Merlin 76/77, 100/130 grade fuel.
MS Gear: 1700hp, 3000rpm, +18psi boost, 10,500ft.
FS Gear: 1475hp, 3000rpm, +18psi boost, 22,500ft.

Merlin 76/77, 100/150 grade fuel.
FS Gear: 1940hp, 3000rpm, +25psi boost, 5500ft.

Data from Lumsden. Who is Lumsden and what is the title of his book?

What is your source for TBOs? USAF Maintenance Manuals scanned at the Museum of the USAF. Also from RAF squadron Maintenance records.
In 1943 Rolls-Royce ran a Merlin 66 for 100 hours continuously, having strengethened components after previous tests, at +18psi and 3000rpm. This became the basis of 100 series Merlines - including the V-1650-9.

This is not the same as taking a random production engine and flying 1000 hours of combat missions, even if they had much less than 20 hours at full throttle. The RAF had trouble making 300 hours TBO on Spitfires, while the USAAF flew an average of 1000 hours TBO in combat missions including full throttle at take off and 5 minutes of combat, IF required.
Secondly, was the 100 Series Merlin used during the war?

 

[SHOOTER]

Data at war emergency rating with water injection at 3000 rpm.

Altitude Ft.	TAS     MP             Throttle
                MPH    "Hg    Blower   Setting
S.L.            401     90	Low	Part   
*6800           431     90	Low	W. O.
**13400         423     90	High	Part   
***21200        451     90	High	W. O.
25000           448     78	High	W. O.

* Low Blower Critical Altitude for 90" Hg., MP
** Altitude for Blower Shift.
*** High Blower Critical Altitude for 90" Hg., MP.

P-51H Performance Test

90" Hg = +30psi boost.

How do you square this with 487 MPH at 25,000' from all the books and the Pilot's Manual?
Just a question regarding sources and data?

 

[DerAdlerIstGelandet]

Shooter, is Wiki your number one source? You source it often...

 

[SHOOTER]

P-51 Mustang Performance

Note that 67" Hg = +18psi boost
81"Hg = +25psi boost

NEAT! Where did you get these numbers? I must be very out of date as to current research and publication because this is the first time I've seen these figures. Some years ago, I spent two months in the Research Library at the Museum of the USAF in Dayton Ohio.

 

[SHOOTER]

P-51 Mustang Performance

Note that 67" Hg = +18psi boost
81"Hg = +25psi boost

See; http://www.wwiiaircraftperformance.org/mustang/p-51h-altperf-91444.jpg
For the performance curves that are quoted in most books. It is the same basic web site as the figures above, but later on the P-51H page near the bottom. It shows 487 MPH at 9,530 pounds. ( 255 Gallons of gas and 2,060 rounds of .50 Cal.)

 

[SHOOTER]

Shooter, is Wiki your number one source? You source it often...

Yes, just because it is so easy! When arguing on line, having a quotable source seems to trump memory from what I read in the past. Wiki has it's problems, but it also has great strengths, like ease of use, broad base of knowledge and in some cases great Notation! I always balk at objections against Wiki when they do not also attack the sources and notes listed in the better and more popular articles.

 

[Aozora]

The only figures that I've ever seen printed in books that show more than 2000 HP are for the post war Hornets at 2,050/2,080 HP depending on the model. I then compare that the P-51H's 2,220HP which was an "in service" late war time, production engine with a 1000 hour TBO, not approached by the post war Hornets.
The second part of the argument is that the Two stage Alison was a terrible engine WO the "fixes" inlet backfire screens, etc. Read Edgar Schmued's book "Mustang Designer" in which he details the effects of the fixes they installed WO Alison approval to prove the problems were not with the plane, but all Alison-GM's! Note that the extra power, 2,300 to 2,220 HP, provided by the Alison engine made the much heavier and huge pod equipped night fighter almost as fast as the A-B models WO the pod!

So you now have published figures, from a book, showing that the Merlin 66 was producing 2,000 hp during WW2.

As it is the, WW 2 Rolls-Royce Merlin R.M.14.SM generated 2,200 hp and so impressed Schmued that he was "eager to use this power plant". I don't have his book, but dollars to donuts it'll be in there:

The P-51 Mustang Variants: P-51H -MustangsMustangs

Rolls Royce had designed a new version of the Merlin, the RM.14.SM, which was proposed to increase the manifold pressure to 120 (from 67 max) and thus improve horsepower to 2,200. Schmued was very eager to use this powerplant. The new Merlin was not heavier than the earlier models. Schmued visited with the engineers at Rolls Royce and they answered his many questions. Schmued left the Rolls Royce factory very satisfied with their cooperation....The engine would not be the newer RS.14.SM Merlin as in some of the lightweight prototypes. The Rolls Royce Merlin V-1650-9 was chosen. Take-off horsepower was actually down from the -7 series to 1,380. But, the new -9 Merlin used water/alcohol injection and was able to up the war emergency power to 2,200 at 10,200 feet.

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?

Source? Read Christopher Shores Chris Thomas' series on the 2nd Tactical Air Force to find out just how much of a contribution the Mosquito made carrying out tactical operations on small targets.

2nd Tactical Air Force, Vol. 1: Spartan to Normandy, June 1943 to June 1944: Christopher Shores, Chris Thomas: 9781903223406: Amazon.com: Books

2nd Tactical Air Force, Vol. 2: Breakout to Bodenplatte, July 1944 to January 1945: Chris Thomas, Christopher Shores: 9781903223413: Amazon.com: Books

2nd Tactical Air Force, Vol. 3: From the Rhine to Victory, January to May 1945: Christopher Shores, Chris Thomas: 9781903223604: Amazon.com: Books

You're also completely ignoring the Mosquitoes roles as a PR aircraft, night fighter, pathfinder, target marker, anti shipping aircraft, to name a few roles.