The “Other” Other Dragon; North American XB-21

November 8, 2022

According to a number of the comments in my previous article on the North American XB-28 Dragon, quite a few people were surprised by the fact that they had never heard of the aircraft. They were also surprised by the choice of the name “Dragon” for the XB-28, because there was another aircraft in service with the United States at the time that used that name – the Douglas B-23.

 

This is another aircraft that I will have to get around to one day, as it too is pretty obscure. But there was in fact ANOTHER American bomber even before the B-23 that had used the name, though informally.

The North American XB-21.

 

And this aircraft is interesting for a whole bunch of reasons. But first a bit of context.

In 1935 the United States Army Air Corp (USAAC) began taking delivery of their newest bomber, the Martin B-10. But this revolutionary aircraft was already by that point recognized as needing replacement soon, and the USAAC had their sights set on something even more impressive.

Boeing’s Model 299, which the USAAC eventually purchased as the B-17. In 1935, when the prototype first flew, this was potentially the most capable and formidable heavy bomber on the planet. But this capability wasn’t cheap and the -299 was a hugely expensive aircraft. So, when the aircraft crashed during testing in October 1935 the USAAC got cold feet.

They decided that putting all their plans into a single, very expensive aircraft type might not be the best policy and instead opted for adopting a “high/low” mix of aircraft to spread the risk. So, in January 1936 they cut the orders of the Boeing 299, which became the YB-17, to just thirteen while they carried on assessments of the type and ordered a much larger number of one of its competitors, the Douglas B-18 Bolo.

This was a much simpler and cheaper aircraft that only had two engines against the YB-17s four. But again, though the B-18 was better (marginally) than what was in service with the USAAC at the time, it was still recognized that aircraft development was moving way too fast for it to stay viable for long and it would need replacing soon.

So, the USAAC immediately put out ANOTHER request for designs as potential replacements for the B-18. And this is where North American came in.

Seeing an opportunity, they began development of a new aircraft, company designated as the NA-21, to be a potential replacement for the B-18. And considering this was North American’s first foray into bombers, it was a surprisingly impressive effort.

 

The XB-21, as it was designated by the USAAC, was an all-metal mid-wing design which was intended to house a crew of six. Powerplant was two Pratt & Whitney Twin Hornets fitted with turbosuperchargers that produced 1,200hp.

First flight occurred in December 1936 and the XB-21 did have much improved range over the B-18 though speed was comparable, with the XB-21 having a top speed of 220mph (354km/h) versus the Bolo’s 217mph (349km/h). But the XB-21 was better armed, with its defensive armament of five rifle-caliber machine guns being one of the heaviest flying at the time. These were located in single-gun positions in nose and dorsal power turrets, plus additional guns firing from a ventral hatch and in left and right waist positions. Now that might not seem that much, but for perspective this was the same level of armament that was carried by the YB-17, an armament so impressive that it had engendered the name “Flying Fortress” for that aircraft.

But where North American really concentrated was in putting the “bomb” into “bomber”.

The B-18 carried a maximum payload of 4,400lbs (1,996kg).

The YB-17 could carry 8,000lbs (3,629kg).

 

The XB-21 could carry 10,000lb (4,536kg).

 

That was the sort of bombload that plenty of aircraft at the end of the Second World War in 1945 couldn’t carry!

Range was curtailed with such a heavy load – only 660 miles (1062km). But with a more standard load of 2,200lb (1,000kg) range was a very respectable 1,960 miles (3,154km).

Test flights at North American did reveal some issues with tail vibration and engine overheating and the aircraft needed some alterations before being handed over to the Air Corps for official testing. But once these began the XB-21 seemed to be a solid aircraft for the day and was judged superior to the updated B-18A that it was competing against.

The USAAC made a tentative order for five preproduction aircraft and it appears here that the name “Dragon” may have started to be applied to the aircraft.

But there was one issue. The B-21 was going to cost an absolute fortune.

The B-18 Bolo might be a mediocre aircraft – though essentially comparable to other aircraft of its time – but it was literally half the price that North American were projecting for the XB-21. Douglas were charging a smidge under $64,000 for their proposed B-18A, a comparatively straight forward improved version of the B-18.

As a result, selecting this aircraft offered additional savings on things like conversion training and part supply, and the fact it was effectively in production also helped make it even more cost effective in procurement terms, plus a lower risk development option.

In contrast North American wanted $122,600 each for the projected B-21. That was B-17 levels of cost – an aircraft that the Air Corps really wanted and would ultimately settle on in a couple of years.

In fact, the USAAC paid North American $555,000 for the XB-21 prototype, a sum that would have bought nearly nine B-18s alone! Additionally, the B-21 would require additional development work and a whole production line constructed.

And as the USAAC were in the course of building up their strength as quickly as possible due to the international situation deteriorating and major budget issues left over from the great crash of less than a decade before, costings were the deciding factor.

Testing with the XB-21 by the Air Corps continued, and the aircraft would have its nose and dorsal turrets faired over after problems were experienced with them. But the order for the five YB-21s was cancelled and the B-18A would succeed the B-18.

However, the limitations of this aircraft were immediately appreciated and again it needed upgrading in less than a year as aircraft performance continued to improve. And so Douglas made their final version, the B-23 Dragon, which had more powerful engines and various improvements and which first flew in July 1939.

Now, as to the choice of the name “Dragon”, well I don’t know who made the decision to call it that. I’m assuming it was the Air Corps, who had intended the name for the XB-21. But maybe it was Douglas, as a way to get one up on North American.

That might seem like an idea rooted in pettiness but considering that relations between American aircraft producers have a history of…not always getting along very well, shall we say, it’s possible.

Whatever the reason North American certainly took the lessons from the XB-21 project to heart. In 1938 they built a new aircraft prototype, the NA-40, designed to match a fresh requirement the USAAC had put out for a medium bomber.

This subsequently evolved into the B-25 Mitchell, a truly great aircraft and one which was far more conservative in its pricing so that it saw a great deal of service and was built by the thousand. The B-25 in turn would lead to the next North American “Dragon”, the afore-mentioned XB-28.

And I have to wonder whether the choice to try to reclaim the name may have been because of some sour grapes at North American. Because quite frankly, it seems to be a little unlucky, as the XB-28 suffered the same fate as its forebear the XB-21; no production orders and reserved for testing.

But despite its failure, the XB-21 certainly deserves to be remembered as both North American’s first foray into bomber aircraft, and for laying the groundwork for its famed descendant.

Sources/Related:

https://en.wikipedia.org/wiki/North_American_XB-21

https://web.archive.org/web/20081121215312/http://www.aiaa-myaerospace.org/rhtp/stories/rusinek_tale.pdf

http://www.joebaugher.com/usaf_bombers/b21.html

The North American XB-28 Dragon – Mini Superfort

Revolutionary; The Martin B-10

“Germany Had No Interest in Heavy Bombers” – The Junkers Ju 89

The Vickers Wellesley – Unheralded Hero of a Forgotten War

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