# The three fastest bombers of WWII



## Vincenzo (Dec 30, 2007)

hi

i thinked this:

Mosquito
Me 410
Do 217M


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## AVRoe (Dec 30, 2007)

What about the
Arado Ar 234 Blitz
Top Speed: 461 mph
Weapons: Rear-firing 20mm cannons; 2,000lbs of bombs


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## Vincenzo (Dec 30, 2007)

sorry i've must write only propellers aircraft


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## Denniss (Dec 31, 2007)

Don't forget the He 177, for an aircraft of it's size it was really fast especially in a shallow dive approach.


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## Thorlifter (Dec 31, 2007)

The B-29 and A-26 were faster than the Do-217M, but only slight.


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## Vincenzo (Dec 31, 2007)

War Machines, italian edition, report 600 km/h for Do 217M


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## B-17engineer (Jan 1, 2008)

For me there's the A-20, the Mosquito, and ahhhhhhhhhhh,,,,,,, Do-217

The He-177 was a disaster with wings, although it was the closest Germany came to a strategic bomber, it suffered from structural failure in flight.


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## HoHun (Jan 1, 2008)

Hi Thorlifter,

>The B-29 and A-26 were faster than the Do-217M, but only slight.

I was surprised to learn that the B-29 still holds a great number of FAI records, including:

Group 1 : piston engine
Speed over a closed circuit of 1 000 km with 1 000 kg payload : 660.53 km/h

Fédération Aéronautique Internationale (FAI) - General Aviation World Records

Now I guess that was probably not achieved in normal service trim, but still very impressive!

Regards,

Henning (HoHun)


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## Denniss (Jan 1, 2008)

B-17engineer said:


> For me there's the A-20, the Mosquito, and ahhhhhhhhhhh,,,,,,, Do-217
> 
> The He-177 was a disaster with wings, although it was the closest Germany came to a strategic bomber, it suffered from structural failure in flight.



It seems you are a little wrong. It initially suffered from burning engines because of a very tight installation. That was solved at least with the A-5.


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## Vincenzo (Jan 2, 2008)

the fai record (1000 km with 1000 kg) is clearly a error in the site.


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## HoHun (Jan 3, 2008)

Hi Vincenzo,

>the fai record (1000 km with 1000 kg) is clearly a error in the site.

Hm, why do you think so?

The B-29 airplane commander manual provides a cruise chart that shows a top speed of about 610 km/h TAS at 9 km, at 40800 kg weight, with the cowl flaps in mid-position, at maximum power.

Removing the turrets, cutting weight down to a minimum and flying at a higher altitude you should realistically be able to achieve a higher speed, especially if the post-war engines could be run at higher ratings (and if you'd be ready to tear them down for inspection and overhaul after the flight).

Regards,

Henning (HoHun)


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## FLYBOYJ (Jan 3, 2008)

Vincenzo said:


> the fai record (1000 km with 1000 kg) is clearly a error in the site.


It's not an error.

There are many records still on the books from the 1930s and 40s.


HoHun said:


> if the post-war engines could be run at higher ratings (and if you'd be ready to tear them down for inspection and overhaul after the flight).


Only if you exceeded CHT or red line RPM for a specified period of time.


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## HoHun (Jan 3, 2008)

Hi Flyboyj,

>Only if you exceeded CHT or red line RPM for a specified period of time.

Hm, I think the only limit they'd have to exceed would be the standard time limit ... have a look at the chart yourself:

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

Cylinder head temperature would be regulated by cowl flap opening, which would have an impact on speed, but power of the turbo-supercharged engines was regulated by boost. 

I wouldn't be surprised if the post-war R-3350 engines could run much higher boost pressures than the war-time engines at the same (maximum) rpm. At least that's the way R-2800 power was increased ... I don't know the details of R-3350 history.

The maximum rpm on that chart is 2600 rpm, by the way, while from a quick look into the manual the redline seems to be 2700 rpm.

Note that even the retracted radar dome subtracts 10 km/h from the top speed ... remove the two top turrets and the bottom turret, and you can expect a 30 km/h speed increase (very roughly).

The chart also is useful for estimating the impact of reduced weight - 20000 lbs weight less are equivalent to a reduction of power required by 200 HP per engine at 30000 ft. More if you are higher ...

Regards,

Henning (HoHun)


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## FLYBOYJ (Jan 3, 2008)

HoHun said:


> Hi Flyboyj,
> 
> >Only if you exceeded CHT or red line RPM for a specified period of time.
> 
> ...


Didn't see any chart - but remember if it's a chart from the POH it may be different from what the engine maintenance manuals states - a very common practice to keep pilots from pushing the limits. Exceedance on CHT and engine RPM is a definite cause for overhaul.


HoHun said:


> Cylinder head temperature would be regulated by cowl flap opening, which would have an impact on speed, but power of the turbo-supercharged engines was regulated by boost.


CHT is also controlled with mixture.


HoHun said:


> I wouldn't be surprised if the post-war R-3350 engines could run much higher boost pressures than the war-time engines at the same (maximum) rpm. At least that's the way R-2800 power was increased ... I don't know the details of R-3350 history.


They have - here's the TCDS for the civilian 3350

TCDS E-272 Rev 9 Curtiss-Wright/Marquette, Inc.


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## HoHun (Jan 3, 2008)

Hi Flyboyj,

>Didn't see any chart 

None at all? The URL I provided links directly to a specific post with a rather large chart. It's in post #31 in that thread if you'd like to locate it manually.

>but remember if it's a chart from the POH it may be different from what the engine maintenance manuals states - a very common practice to keep pilots from pushing the limits. 

All the more reason to consider the FAI record possible 

>CHT is also controlled with mixture.

Good point - the increased fuel use might be another reason that they didn't use this power level for the long distance records!

>They have - here's the TCDS for the civilian 3350

Highly interesting, thanks! But these are tubo-compound engines, I don't believe that's what they used in the record-breaking B-29.

Here is an interesting overview:

http://www.enginehistory.org/Wright/CWafter1930_2.pdf

On page 13 of the PDF, there is a minor subtype listed with only 8 engines produced for use in the B-29 in 1946: The R-3350-65 with 2500 HP @ 2800 rpm take-off rating. As the records were set in 1946, I wonder if these were the engines used for it ... the FAI page lists the basic R-3350-23, though. I think they accepted the record breakers' statements with regard to the hardware, though (as the Soviet records show 

Regards,

Henning (HoHun)


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## FLYBOYJ (Jan 3, 2008)

I don't things have changed much since the B-29 record flight and flight done in later years but I could almost guess that any record event wasn't done at the expense of destroying engines. My father in law was involved in several world record flights and after those flights the aircraft were delivered to operational units.


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## Vincenzo (Jan 3, 2008)

is a wrong first the b 29 wasn't a bi engine
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.
I never read that b 29 run at 610 km/h, common is a max speed slighty over 570 km/h


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## FLYBOYJ (Jan 3, 2008)

HoHun said:


> On page 13 of the PDF, there is a minor subtype listed with only 8 engines produced for use in the B-29 in 1946: The R-3350-65 with 2500 HP @ 2800 rpm take-off rating. As the records were set in 1946, I wonder if these were the engines used for it ... the FAI page lists the basic R-3350-23, though. I think they accepted the record breakers' statements with regard to the hardware, though (as the Soviet records show
> 
> Regards,
> 
> Henning (HoHun)



Hard to say - those engines being delivered might be the completion of a contract order - unless we could get the S/Ns and trace them to specific airframes, its any one's guess.


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## HoHun (Jan 3, 2008)

Hi Flyboyj,

>I don't things have changed much since the B-29 record flight and flight done in later years but I could almost guess that any record event wasn't done at the expense of destroying engines. 

Oh, I don't think that they were destroyed - just torn down and thoroughly inspected afterwards, like normal service engines which had accumulated a certain time at emergency power settings were, too. The only difference would be that the record engines accumulated that time on a single occasion. 

(For the Rolls-Royce Merlin, the operational five minute limit was simply disregarded during time-to-altitude climb tests. Of course, the Merlin was liquid cooled - I don't know if air-cooled radials would take that as easily.)

Regards,

Henning (HoHun)


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## FLYBOYJ (Jan 3, 2008)

HoHun said:


> Hi Flyboyj,Oh, I don't think that they were destroyed - just torn down and thoroughly inspected afterwards


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.



HoHun said:


> (For the Rolls-Royce Merlin, the operational five minute limit was simply disregarded during time-to-altitude climb tests. Of course, the Merlin was liquid cooled - I don't know if air-cooled radials would take that as easily.)
> 
> Regards,
> 
> Henning (HoHun)



I think the larger radials would be way more durable....


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## HoHun (Jan 3, 2008)

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)


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## FLYBOYJ (Jan 3, 2008)

HoHun said:


> 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!


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## HoHun (Jan 3, 2008)

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)


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## FLYBOYJ (Jan 3, 2008)

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."_


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## HoHun (Jan 3, 2008)

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)


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## HoHun (Jan 3, 2008)

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)


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## Vincenzo (Jan 3, 2008)

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


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## FLYBOYJ (Jan 3, 2008)

Vincenzo said:


> 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.


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## HoHun (Jan 3, 2008)

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)


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## Vincenzo (Jan 3, 2008)

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


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## HoHun (Jan 3, 2008)

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 | FÃ©dÃ©ration AÃ©ronautique Internationale - FAI

Good work uncovering this mistake! 

Regards,

Henning (HoHun)


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## Vincenzo (Jan 3, 2008)

my english is too bad for write to fai


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## Graeme (Jan 4, 2008)

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.


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## HoHun (Jan 4, 2008)

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)


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## FLYBOYJ (Jan 4, 2008)

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. 



HoHun said:


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


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## Vincenzo (Jan 4, 2008)

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


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## HoHun (Jan 4, 2008)

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)


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## FLYBOYJ (Jan 4, 2008)

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


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## Vincenzo (Jan 4, 2008)

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."


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