The three fastest bombers of WWII

[HoHun]

Hi Flyboyj,

>That's what I meant - I don't think anyone would want to push these engines into a overhaul, especially if they were brand new. If they met operating parameters and held compression I would think they kept right on using them.

This is an example from the P-51 manual:

"The engine must be removed for a complete knock-down inspection after 5 hours [of running at war emergency power]".

If the R-3350 was as durable as the P-51's Merlin (or better), they might have used up maybe two or three of these hours and then passed the aircraft on, if they were really using an operational aircraft.

However, I imagine that in 1947 - shortly after Churchill's "Iron Curtain" speech and the emergence of the independend USAF -, records as means of demonstrating the capabilities of USAF atomic bombers in the incipient Cold War might have been considered important enough to make the service live of a couple of aero engines a secondary consideration.

Regards,

Henning (HoHun)

 

[FLYBOYJ]

However, I imagine that in 1947 - shortly after Churchill's "Iron Curtain" speech and the emergence of the independend USAF -, records as means of demonstrating the capabilities of USAF atomic bombers in the incipient Cold War might have been considered important enough to make the service live of a couple of aero engines a secondary consideration.

Regards,

Henning (HoHun)

Perhaps - but I don't think that would go over too well with the squadron's maintenance officer!

 

[HoHun]

Hi Flyboyj,

>Perhaps - but I don't think that would go over too well with the squadron's maintenance officer!

LOL! No doubt about that!

Regards,

Henning (HoHun)

 

[FLYBOYJ]

Found this from another site....

"I got in touch with several people who flew or worked on the R3350 in both military and civil service and was lucky enough to talk to a pilot/ engineer who still flies the Martin Mars water bombers up here.

OK TBO of 3500 hours in civil service. Well depends what you mean by TBO. The R3350 started out in 1944 with about a 30 hour lifespan in the severe duty on the B29 hauling heavy bomb loads to Japan. This was very hard on them at high power settings and in high blower for hours. Steady improvements were made post war to these engines. It appears as though Wright set the TBO at 2000 hours initially in the early '50s and increased this to 3500 hours in the early '60s when they started a SOAP program. My sources said few if any R3350s remained on wing for this period as the oil analysis showed problems well before this time and many jugs were replaced along the way. The jugs were often damaged by the sodium cooled exhaust valves disintegrating. All the people I contacted said that when operated in high blower, engine life plummeted by about 50%.

The US Forest Service sets the TBO on their R3350s in the Neptune at 1600 hours today and say they routinely make it there with no jugs replaced. Locked in low blower and limited to 51 inches dry.

The Martin Mars water bombers have their TBOs set at 800 hours. They are not turbo compound models. Steve Wall said only 2 engines ever made it that far with no jugs replaced. They have a problem with master rod thrust bushings disintegrating. The overhaul costs on these engines is over $200,000! Again this is a hard life with heavy loads but they limit manifold pressure and high blower is locked out.

In military service on the ASW mission and C-121 intelligence gathering at low altitude, the lifespan was pretty good due to low power settings and most of the time in low blower.

In civil use on the Super Connie, experiences seem at both ends of the spectrum and maybe time has made some forget the facts a bit. One quote stuck out: "... I don't remember ever having a flight of more than six hours that I landed with all four running. With the TC engines, the Connie became known as the Worlds Fastest Tri-motor".

The following link should provide a few chuckles. This is from a line mechanic with Quantas on the Connie: LIVING WITH THE DA3 - The Lockheed File

Airline use was a hard life in high blower most of the time. The man hours per flight hour going into a four engined airplane were staggering and why the jet was such a leap forward despite the very high fuel consumption.

My piece of personal trivia on these engines involves living on an RCAF base in the '60s and having a four engined Argus take off over the house with full wet power-3700hp X 4. What a noise. The ground shook!

Now the 1650 cubic inch Merlin in airline service in the same era- Canadair Northstar (4 engines). Used by TCA, CPA and BOAC. Again life started out grim. TCA had 20 in flight shutdowns in one month! With takeoff power set at 1660hp at a staggering 71 inches. Cruise power was initially set at 40 inches and 1100hp. Engine life on wing was 200-450 hours in most cases. With a lowering of cruise power to 950hp, life picked up considerably. Over a one year period and 957 ocean crossings, 2 engines made it past 2000 hours, 7 made it to 1750 and the average life on wing was 654 hours (no jug changes on the Merlin). TBO was set at 1250 hours although this was just as meaningless as with the Wrights.

Initial problems were with the intercooler pump seals, compressor surging, coolant leaks and erroneous fire warning lights. Rolls Royce offered TCA a "won't be sorry" warranty on their Merlins- 6000 hours or 3 years. They would pick up the tab on any unreasonable wear or failures. RR probably lost money on this one! The Merlins on the North Stars were in a power egg which had rads and almost all parts attached in one piece for quick removal and replacement. Good idea. They needed it. It appears that very few Merlins had catastrophic failures- indeed, one was held at full takeoff power for 5 hours in a flight test until the oil supply ran low- pretty tough. Coolant leaks caused most of the shutdowns.

The RAF and SAAF also used the Rolls Royce Griffin in the Avro Shackleton ASW patrol aircraft. I was not able to contact anyone with experience on these 4 engined aircraft but they were in use many years over the oceans.

Research showed that the Pratt R-2800 was the engine to have in this era. Better reliability and fuel consumption than either the Merlin or the Wright. The Pratt 4360 was horrible by all accounts I found. In any case, the jet quickly replaced them all."

 

[HoHun]

Hi Vincenczo,

>is a wrong first the b 29 wasn't a bi engine

Hm, true, that's an obvious typo in that dataset.

>second is very strange that a large plane like b29 can run with 5 tons payload same distance at only 595 km/h, or run 2000 km with 2 tons a 588 km/h (and with 1 ton same speed) can run 1000 km with 1 ton a 661 km/h.

It's not entirely strange as the top speed is achieved at extremely high altitude where extra weight increases induced drag considerably.

That the longer distance can only be covered at slower speed is logical, too - the extra fuel for the second 1000 km are dead weight for the first 1000 km, so we have more induced drag again. Additionally, the engines probably can't keep up the high power setting without danger of failure for the entire distance, leading to a further reduced speed.

>I never read that b 29 run at 610 km/h, common is a max speed slighty over 570 km/h

Here is the graph that shows 610 km/h:

http://www.ww2aircraft.net/forum/aviation/mission-moscow-hypothetics-8720.html#post262133

Note that the graph only covers altitudes up to 30000 ft (ca. 9 km), if you go higher the speed still increases up to the critical altitude of the engine.

The top speed depends very much on the current flying, on the status of the defensive armament, and on the power setting used.

If you look at the graph, 570 km/h is about the speed at 30000 ft, 2400 rpm/43.5" Hg (maximum continuous), 110000 lbs weight, in a B-29 with turrets installed but no radar dome, for example.

Remove the turret and the plane will both be lighter and have less drag, increasing the top speed quite a bit.

If the conditions under which the top speed you listed are not given, it's not very useful for judging the performance of the B-29. (This is a problem with most performance data for bombers as they had such a large possible weight range.)

Regards,

Henning (HoHun)

 

[HoHun]

Hi Flyboyj,

>Found this from another site....

Thanks a lot, many interesting figures in there! The greatest gap is probably between early development stage, war-time, military use and civilian use of *any* kind

Regards,

Henning (HoHun)

 

[Vincenzo]

the chart not clear the point, why the other records is so low speed?

 

[FLYBOYJ]

the chart not clear the point, why the other records is so low speed?

Its a matter of when the attempts were made on the records. many of those records involve time, distance and payload and sometimes those attempting to break a record may not be configured to do one in a certain time and class. My father-in-law set 86 world speed and altitude records in 1986, I believe some of them were held by post WW2 aircraft.

 

[HoHun]

Hi Vincenzo,

>the chart not clear the point, why the other records is so low speed?

The problem with the chart is that it only goes to 30000 ft, while the highest speeds are reached at an altitude above that.

The reason for the lower speeds for the other records: Weight of fuel.

At high altitude, heavy weight means high induced drag, which means low speed.

The slowest speed record was achieved by the crew of RG Ruegg:

Fédération Aéronautique Internationale (FAI) - Aviation and Space World Records

As you can see from the list, they made only one flight with 10000 kg payload, and earned the records for 10000 kg, 5000 kg, 1000 kg and without payload with it. It was the heavy weight that set the speed, and if you look at the photograph of the crew with their plane in the background, it looks as if it was a standard B-29 with turrets in place, so it was slower than the turret-less planes probably used for higher-speed records:

Fédération Aéronautique Internationale (FAI) - Aviation and Space World Records

(I haven't looked at all of the pictures, but most unfortunately don't show enough of the plane to judge its equipment status, and the photographs simply labeled "B-29" might show a stock photograph because it's the same for several records - though it looks a bit like a stripped-down record breaker indeed.)

Some unrelated background information on the high-speed record crew (looks like they flew with pilot and co-pilot only):

Two turning, one burning Air Classics - Find Articles

Regards,

Henning (HoHun)

 

[Vincenzo]

the article give me reason the record is from A26, fai site is wrong some can write to fai for corrrection??

 

[HoHun]

Hi Vincenzo,

>the article give me reason the record is from A26, fai site is wrong some can write to fai for corrrection??

Hm, good thinking there - I believe you must be right!

The XA-26F had three engines though, so it doesn't fit the description either

Here is a link to the picture of the record pilots in front of their plane:

Fédération Aéronautique Internationale (FAI) - Aviation and Space World Records

Not much is visible ... can someone tell for certain which plane type it is?

A two-man crew is standard in the A-26, while the B-29 - though still legal with a two-man crew - would probably additionally carry a flight engineer at least, especially if you plan on getting the last bit of power out of your engines.

Oh, and here is the link to the FAI email form:

Contact the FAI Office | Fédération Aéronautique Internationale - FAI

Good work uncovering this mistake!

Regards,

Henning (HoHun)

 

[Vincenzo]

my english is too bad for write to fai

 

[Graeme]

Can't find an accurate first flight for the VB-109, so I'm not sure if it falls into the threads category. Most sources state 1945 or late 1945.

I've got 447mph at 9,000m for Myasishchyev's high-altitude twin-engined bomber.

 

[HoHun]

Hi Vincenzo,

>Do 217M

Hm, which speed do you have for the Do 217M? I'm asking because I wonder if you have considered the Junkers Ju 88S, too ... it's hard to find reliable data on the type, but the versions with GM-1 injection must have been very fast indeed.

Regards,

Henning (HoHun)

 

[FLYBOYJ]

Hi Henning;

I can't access the FAI site from this from work but are you sure the category isn't for "multi engine" or has a provision for 3 or more engines? I know the FAI is a pretty tight organization and there must be some reason why the XA-26F is listed. Perhaps it has an APU and they are counting that as an engine? Just a guess.

Hi Vincenzo,

>the article give me reason the record is from A26, fai site is wrong some can write to fai for corrrection??

Hm, good thinking there - I believe you must be right!

The XA-26F had three engines though, so it doesn't fit the description either

Here is a link to the picture of the record pilots in front of their plane:

Fédération Aéronautique Internationale (FAI) - Aviation and Space World Records

Not much is visible ... can someone tell for certain which plane type it is?

A two-man crew is standard in the A-26, while the B-29 - though still legal with a two-man crew - would probably additionally carry a flight engineer at least, especially if you plan on getting the last bit of power out of your engines.

Oh, and here is the link to the FAI email form:

Contact the FAI Office | Fédération Aéronautique Internationale - FAI

Good work uncovering this mistake!

Regards,

Henning (HoHun)

 

[Vincenzo]

For do 217M i writed is 600 km/h from "War Machines" italian edition, for ju 88s is there hasn't bomb bay i don't consider it bomber.
the wrong of fai is not listed a26

 

[HoHun]

Hi Flyboyj,

>I know the FAI is a pretty tight organization and there must be some reason why the XA-26F is listed. Perhaps it has an APU and they are counting that as an engine? Just a guess.

Slight misunderstanding here: The FAI lists the 660 km/h record for a B-29 with 2 engines (!), but googling the names of the two-man crew, I found an article about just these two guys testing the XA-26F, which was an A-26 with an additional jet engine in the tail.

Vincenzo has suggested that the FAI is wrong in listing the record for a B-29, and in fact the aircraft in the background of the FAI crew photograph does not look like a B-29 (though all you see is one wheel and a fuselage or nacelle flank).

To me it looks as if the 660 km/h was achieved either with a standard A-26 (if the FAI data regarding 2 engines is correct), or with the jet-augmented XA-26F.

Regards,

Henning (HoHun)

 

[FLYBOYJ]

Ahhh..... now I see....

 

[Vincenzo]

From article HoHun linked
"On June 1946, the XA-26F covered a 621-mile (1000 kilometer) course with a 1000 kilogram load at an average air speed of 413 mph. The aircraft was being flown by Lt. Col. T.P. Gerrity and Capt. W.K. Rickert. With all three engines operating, the XA-26F reached a top speed of 435 mph at 15,000 feet."