The Me109E had two rifle caliber Mg's and two low powereed cannon. Later 109's had only 3 weapons two mg's and a cannon that's all they could carry without serious performance penalties. Marseilles blew P-40's and Hurricanes out of the sky in ME109F with 1 20mm cannon 2 light mg's. The 13.2mm Browning would be about equivalent to US .50 MG with added benefit of explosive shells. Two 7.92mm Mg and two 13.2mm with explosive shells would have been more than adequate at any time in WWII and was quite powerful for 1939- as good as or better than Me109E with two 7.92mg and two low velocity 20mm MGFF cannon.

This seems like a failure of the thought proccesses. If you were going to arm it with pop-guns, why not build a mini-plane like the Cauldron racers conversions or P-77? But at this puppies size, it will loose all of the advantages that acrew to the mini-plane.

Nice aircraft from The Netherlands - I agree, very namby-pamby armament - I mean, pea-shooters (Which were reserved for British bombers!).

As WW2 was coming near, getting engines was quite difficult as most countries kept them for themselves. The Walter Sagitta-engines were not intended, but they were available and this speeded up flight-testing. As for armament the productionversion of this type surely would have hadmore/heavier guns then in this prototype.

Note that the D.XXIII is not the usual twin-engined fighter. It is little larger than a Hurricane and represents an alterative to the usual single-engined fighter - getting high power by two small engines instead of one large one. (Think MiG-19) I would have used the Gnome-Rhone 14M radial with FW190-style fan cooling, and with 100-octane fuel, these interesting little engines might have been good for nearly 1000 HP each. And I agree that the tail booms cried out for heavier armament, which for me would mean two Oerlikon 20mm FFS (the aircraft version of the familiar AA gun). But bailout...???

hoeveel waren er in de tweede wereldoorlog in dienst?

Another "various problem" was rear propellor vibraton, a BIG problem common t many pushers. The Do-335 and Cessna 337 didn't change the world. Had they continued development underground, D.XXIII would have rolled out of the cave just in time for the VE Day parade but missed the fly-past.

-Well, the armament is a little weak. How about two 13mm Brownings and a brace of Madsen 23mm in the wings?
-As for power, the Bristol Taurus was available.
-Even so, given a first flight in May of 1939 it would have been too little, too late.
-Imagine a couple of squadrons of these in Finland. Uncle Joe would not have been happy at all...

would this have stood up to the me-109 in 1940, if things had worked out differant?

Imagine this with the hispano engine of 890HP + replace the rifle calibre mg with 13mm,
This might be possible without rebuilding the airframe. Now we have a real contender - a P38 in 1940!