Indigenous Danish Fighter?

[blockhaj]

@Orla what's your source for the above statements?

 

[Orla]

Quite a lot of hours (Saturdays) researching at the Danish National Archive (Rigsarkivet) in Copenhagen. And a lot of years researching into the Hærens Flyverkorps, later Hærens Flyvertropper and Marinens Flyvervæsen flying equipment.

 

[blockhaj]

Quite a lot of hours (Saturdays) researching at the Danish National Archive (Rigsarkivet) in Copenhagen. And a lot of years researching into the Hærens Flyverkorps, later Hærens Flyvertropper and Marinens Flyvervæsen flying equipment.

Are you working on some book etc? I have a fairly big interest in the danish D.21. Could u confirm if it was designated IIIJ as stated by the danish air force museum? Also do u happen to know what bombs it could carry (if any) and were the aircrafts hardpoints were located etc?

Danmarks Flymuseum - Fokker D. XXI (IIIJ)

Et 7600 m2 stort, moderne og levende flymuseum med 50 danske og udenlandske luftfartøjer fra 1911-2000. Bl.a. svævefly, veteranfly, jagerfly og helikoptere.

flymuseum.dk

 

[SilverBud]

Hi Justo.

Thanks for your feedback, you seem to know very much of the danish situation these days, but unfortunately all is known facts to me, as I have been investigating into the Hærens Flyvertropper and Marinens Flyvervæsen for almost 30 years now.

A couple of updating facts.
There was 7 Fokker D.XXI ready for active service on April 9th. 1940. Two others was missing a tailwheel and a fueltank. The one with the lovest flying time had only 15 minutes in the log including testflight and transport from Kløvermarken to Værløse, so wery untested equipment.
D.XXI J-42 did not have two 23mm. Madsen macnine guns under its wings when testing, but one 20mm. and one 23mm. canon as the Hærens Flyvertropper wanted to test the reliability, functionality and service ability for each veapon. In the end, the 20mm. canon proved much more reliable than the 23mm. and thus was chosen for the task. For some reason, political I guess, the ordered 24 pcs. of 20mm. Madsen machine guns and ammunitions was never delivered from the factory. The D.XXI fighters was camouflaged, had 6 roundels (Danish markings) and 6 danish split flags on all surfaces on the tail to show neutrality.
So has all fighting aircraft, the Gloster Gauntletts, the Fokker C.V. as wel. The training and liason aircraft still was silver doped.

The Marinens Flyvervæsen had two torpedo amphibian planes, several Heinkel HE-8 and the Gloster Gauntlet fighters on strength.
The P4/34 project was planned and production started (beginning) and 12 Rolls Rouce engines had been purchased as well. One of the Marine pilots was also testing the D-XXI with only one canon firing as the navy wanted to equip the P4/34 plane with one 20mm. Madsen machine canon in one wing and 4 Madsen 8mm. Machine gun in the other.

The two (not one) Cierva C.30 autogyro was already grounded as they were unflyable for the pilits and usually enden in a crash when starting or landing.

There was two (not one) de Havilland Dragonfly liason plane on strength. At the outbreak of the was one was in Jutland.

Hærens Flyvertropper never had realistic plans for further Fokker D.XXI fighters as the political landscape was against strengthen the military.

Two Heinkel HE114 was ordered from Heinkel and a contract was signed on April 1st. 1940, but cancelled about 14 days later.

There was drawn up a contract for 12 Macchi M.C.200 from Italy, but never signed. The Macchi M.C.200 fighters would have been delivered unarmed so either way the Marinens Flyvervæsen would have needed to test and decide for a danish armamant of Madsen origin.

A license contract for 12 Fokker G.1 recon/bommer/heavy fighter was signed and several workers was at the Fokker factory to learn to build the plane. Engines was a pain point as Bristol engines was not available. There were plans to acquire further 12 Fokker G.1 from Fokker in Holland and even to build a further 12 Fokker G.1 planes, but they were plans only.

The Marinens Flyvervæsen fighter project was a one plane only project, thus with several fuselage designs and two different wing arrangements, a straight and a gull wing design, but is was only "emergency thinking" as there were no funds and no political backing the project. With the size of the plane, the armament of 4 8mm. Madsen machine guns with plenty of rounds would save no space for bombs or other ordonance. The fuel capacity would have been very small as the fueltank was positioned in the opper fuselage in front of the cockpit behind the firewall. Not at all a fighter project that could have made any difference in a war, but might have had some effect when training student pilots.

Regards
Orla

I'm highly interested in this 23mmx20mm configuration since I've never come across anything about 23mm cannons on the IIIJ until now. Do you have some more in-depth knowledge on these tests with the 23mm mounted?

 

[Orla]

Quite a lot of hours (Saturdays) researching at the Danish National Archive (Rigsarkivet) in Copenhagen. And a lot of years researching into the Hærens Flyverkorps, later Hærens Flyvertropper and Marinens Flyvervæsen flying equipment.

Are you working on some book etc? I have a fairly big interest in the danish D.21. Could u confirm if it was designated IIIJ as stated by the danish air force museum? Also do u happen to know what bombs it could carry (if any) and were the aircrafts hardpoints were located etc?

Danmarks Flymuseum - Fokker D. XXI (IIIJ)

Et 7600 m2 stort, moderne og levende flymuseum med 50 danske og udenlandske luftfartøjer fra 1911-2000. Bl.a. svævefly, veteranfly, jagerfly og helikoptere.

flymuseum.dk

Hi.

Yes, I can confirm that the Danish Fokker D.XXI fighters was designated III-J (Tredje jager type/Third fighter type) and had fuselage number J-41, J-42 (Both purchased in Holland, later updated to Danish standard), J-43, J-44, J-45, J-46, J-47, J-48, J-49, J-50, J-51 and J-52 (J-52 was not finished and delivered to Hærens Flyvertropper on April 9th. 1940).

I was/am working on a book regarding the Danish Fokker D.XXI fighters, but it will take some time before it will be finished. I am though, building a 1:1 replica of the Fokker D.XXI in Danish service. (See attached picture).

There was plans for the Danish Fokker D.XXI to be equipped with bombs, or actually with bomb boxes incorporated into the wings, two boxes carrying a total of 8 pcs. of 12,5 Kg. bombs. They were to be positioned outside of the Gun Bay for the Madsen 20mm. canon, and in-between the two Box spars for the main wing. It was plans only as I have never found any drawings for the bomb boxes, only written documentation for the idea. Should the D.XXI be send into battle with 2 pcs. 8mm. Madsen machineguns with 500 rounds each positioned in the fuselage, two 20mm. Madsen machine canons with 150 rounds each and bomb boxes for 8 pcs. of 12,5 Kg bombs, and a full fuel tank, it would have run considerable over it's max take off weight!

The Hærens Flyvertropper never had any experience with bombs other than the 12,5 Kg bombs carried by the Fokker C.V recon./bombers. Some bombs were even smaller than that.

 

[blockhaj]

Awesome information. And it's kinda hardcore to do a 1:1 model XD
I know i'm going a bit off topic here but do u happen to have information the Danish air force 20 mm Madsen? Like did it differ from the AA or AT version, what ammunition did it have, what performance did it have, etc?

 

[Orla]

I'll see what I can find. I have some information in my archives, so it will take a while before I come back.

 

[blockhaj]

As for the bomb boxes, this idea was fairly common in the 30's. I know a fair bit of Swedish projects with bomb boxes for 12,5 kg bombs, would it be possible that the Danes were inspired by the Swedes?

 

[Orla]

I think they were generally inspired as every bombs hung under the wing hanging outside the wing produced drag. I even think the bombs were Bofors produced.
The Danish Fokker C.Ve recon./bomb planes were to have had bomb boxes as well, bud enden up with under wing arrangements, most likely due to lack of funding for rebuilding the lower wing.
When the Danish Fokke C.Ve were in Luftwaffe service in the Baltics, they were equipped with 4 pcs. 50 Kg. bombs hung under the fuselage.

 

[Orla]

Attached a picture of the Danish used 12,5 Kg bombs hung under a Fokker C.Ve lower wing.

 

[blockhaj]

To stay off topic, do u happen to know if the IIIJ J-41 and J-42 were re-engined with Mercury VIII engines later to fit in with the Danish produced ones?

 

[Orla]

After April 9th. 1940, the Danish were forbidden to fly the military planes, and as the government was thinking that this would be a short war (As Poland etc.), they decided to repair the damaged planes and store them where possible. Both III-J J-41 and J-42 were not even camouflaged as they acted as "master" planes for the 10 pcs. Danish build ones. But, as with all the remaining planes, J-41 and J-42 were upgraded from the Dutch version to the Danish version, including changing the Gloster Gauntlet Bristol Mercury VIs engine (625PS) to the more powerful Bristol Mercury VIII (840PS) engine. Both planes also had the propeller changed from the Ratier to a Hamilton Standard, same as the Danish build was equipped with. I have no documentation for the undercarriage, as J-41 and J-42 had the Fokker version for the Ratier propeller, and the Danish build version had a longer "leg" due to the larger Hamilton Standard propeller. The undercarriage legs for the Danish version was purchased in Germany. When finally stored, J-41 and J-42 was looking exactly like the Danish build version, even the engine cowling was altered and bigger no longer showing the 9 bulkes where the cylinder top was. The were camouflaged as well. Still, no 20mm. Madsen canon was delivered and mounted. Besides J-42, which was the test plane for the Madsen canon, I dont even think the remaining planes had the brackets and wing strengthening equipment for the canon installation. One plane, J52, was delivered after April 9th. as it was not finished, and J-49 was scrapped as it was too badly damaged for repair.

 

[blockhaj]

While at it, do u have information on the danish Fokker G-1?

 

[Orla]

Yes, I wrote a small book about it
Short recap. Hærens Flyvertropper ordered a license to build 12 Fokker G.1, and did send a number of workers to the Fokker Factory to learn how to build the plane. Fokker forwarded a bunch of drawings, 5.000+, of which no signifikant number of drawings exist to my knowledge. Hærens Flyvertroppers Værksteder started to redraw all the drawings to Danish standard and did start som very simple wood working tests, BUT no real production was ever started. The 12 planes was supposed to have two Bristol Mercury V.III engines, but due to the coming war, it was not possible to acquire these engines from England, so both the Focke Wulf 801 engine, a couple of Italian radial engines and even an American engine was considered, but no real action done.
The Danish Fokker G.1 should fill the position of both a recon. plane, thus the "glasshouse" fuselage underside for all planes (It was interchangeable with fx. the bomb rack system), and as a heavy fighter and a bomber plane. The bomber plane should have dive-brakes under the wings outside the engines.
The were supposed to be armed with two 20mm. Madsen canons and two 8mm. machineguns in the nose and a reward firing 8mm. Madsen machinegun in the rear fuselage.
The political landscape and the lack of funds for defending Denmark was most likely the reason for the planes fate, as no real production ever was started.
Even though, in Hauptman Falcks notes for the attack on Værløse airfield, it is mentioned that the Danes have been building the Fokker G.1, but that it was not on strength yet, though he should be aware that one or two might be active on the airfield. Looking at the attach plan for Weserübung, the German research was not very good at they totally did forget the Marinens Flyvevæsen planes, the Havker Nimrods, HE-8 etc.

 

[blockhaj]

Yes, I wrote a small book about it
Short recap. Hærens Flyvertropper ordered a license to build 12 Fokker G.1, and did send a number of workers to the Fokker Factory to learn how to build the plane. Fokker forwarded a bunch of drawings, 5.000+, of which no signifikant number of drawings exist to my knowledge. Hærens Flyvertroppers Værksteder started to redraw all the drawings to Danish standard and did start som very simple wood working tests, BUT no real production was ever started. The 12 planes was supposed to have two Bristol Mercury V.III engines, but due to the coming war, it was not possible to acquire these engines from England, so both the Focke Wulf 801 engine, a couple of Italian radial engines and even an American engine was considered, but no real action done.
The Danish Fokker G.1 should fill the position of both a recon. plane, thus the "glasshouse" fuselage underside for all planes (It was interchangeable with fx. the bomb rack system), and as a heavy fighter and a bomber plane. The bomber plane should have dive-brakes under the wings outside the engines.
The were supposed to be armed with two 20mm. Madsen canons and two 8mm. machineguns in the nose and a reward firing 8mm. Madsen machinegun in the rear fuselage.
The political landscape and the lack of funds for defending Denmark was most likely the reason for the planes fate, as no real production ever was started.
Even though, in Hauptman Falcks notes for the attack on Værløse airfield, it is mentioned that the Danes have been building the Fokker G.1, but that it was not on strength yet, though he should be aware that one or two might be active on the airfield. Looking at the attach plan for Weserübung, the German research was not very good at they totally did forget the Marinens Flyvevæsen planes, the Havker Nimrods, HE-8 etc.

Great info. Did the DAF ever designate it? Like would it have been something like IB?

 

[Orla]

No, it actually should be designated with an "R" for recon, for some reason. R-61 to R-73.

 

[blockhaj]

No, it actually should be designated with an "R" for recon, for some reason. R-61 to R-73.

So the IVR?

 

[Orla]

Yes, IV-R, forth recon plane.

 

[blockhaj]

I am not sure. My sources about the CW-21 of Loi Wing are not reliable.
It seems to exist certain confusion between the Danish Madsen 11.35 x 62 and the Belgian FN-Browning 13.20 x 99 machine guns that were expected to be used by the CW-21 B of the ML-KNIL.
It is possible that the Chinese, after suffering bad experiences with the Gloster Gladiator Mk.I armed with FN of 7.92 mm in 1938, decided to acquire Danish weapons.
I can confirm the use of the Madsen 11.35 x 62 in the Curtiss H-75 N of the Thai Air Force in 1938.
Source: DOCAVIA No. 22

What sources exist that talks about the CW-21B ML-KNIL armament? I find it very interesting that they were to use 13,2 mm FN guns?