Fokker D.XXI in Dutch service

Juha · Dec 20, 2008

Hello Marcel
a/c were individuals, some were a bit faster than others even from the same production batch. And by careful filling and polishing it is possible to gain some extra speed. So with a different prop, smoother skin, w/o the bulge for the landing light and possible small differences in landing gear IMHO 430kmh is possible for a good example. And with small aerodynamic improvements here and there some extra gains are perfectly possible. So 436, 440 or even 446kmh, maybe, but I don't know. And anyway, during intensive combat period at least the smoothes of skin would deteriorate with some loss of speed.

Juha

Marcel · Feb 1, 2009

Some pictures I took of the replica at Soesterberg. The lights are very bad in the museum, sorry for that.

Marcel · Feb 1, 2009

Juha said:
Hello Marcel
a/c were individuals, some were a bit faster than others even from the same production batch. And by careful filling and polishing it is possible to gain some extra speed. So with a different prop, smoother skin, w/o the bulge for the landing light and possible small differences in landing gear IMHO 430kmh is possible for a good example. And with small aerodynamic improvements here and there some extra gains are perfectly possible. So 436, 440 or even 446kmh, maybe, but I don't know. And anyway, during intensive combat period at least the smoothes of skin would deteriorate with some loss of speed.

Juha

I found out that the Dutch a/c actually had a smoother cowling. Also the propeller was different. After the Dutch bought it, Fokker did everything to reach the 460 km/h speed as required in clean configuration. And the succeeded. The speed of an operation D.XXI was not 415 km/h as I stated earlier, but around 435 km/h at the acceptance trials (source Fokker).

Juha · Feb 2, 2009

Thanks Marcel!
And nice pictures, I also took some photos of the replica when I visited Soesterberg in 2005.

Juha

Fokker D21 · Feb 3, 2009

Thanks from me as well.

Then to think that our Dutch government at first didn't want it. I sure hope we are not going to make the same mistake again by not buying the F-35 Lightning 2.

Marcel · Feb 4, 2009

Hi Fokker, good nick
I see you're from the same town as I am.

Viikate · Feb 5, 2009

Hello all! I had to register just for this thread

So what it the final verdict on the speed issue? I would like to know TAS of Dutch variant at sea level and 5000m.

Would these be close? 340km/h TAS at sea level 440km/h TAS at 5000m

Thanks!

Marcel · Feb 5, 2009

Hi Viikate,

Viikate said:
Hello all! I had to register just for this thread

So what it the final verdict on the speed issue? I would like to know TAS of Dutch variant at sea level and 5000m.

Would these be close? 340km/h TAS at sea level 440km/h TAS at 5000m

Thanks!

I hope it was worth it

I'm still not 100% sure. I found info from Fokker, claiming at the acceptance trials a speed of 435 km/h at 5000m. This was supposingly with full gear, although this was the 212, which lacked for instance the radio at the time, AFAIK. Clean, the D.XXI clocked 460 km/h at 5000, that's for sure. I could not read the whole report. I'm still planing for a trip to Lelystad, where the Fokker archieves are stored. There should be a wealth of info there.

Viikate · Feb 5, 2009

Definately worth it

460 km/h sounds bit too much. I would like to have it in some normal combat weight setup with radio and such, since I'm trying to make a flight model for sim. 435 sounds pretty good, so I'll go with this value or maybe slightly less.

Also it would be helpfull if someone could confirm the amount of cannon rounds in danish fokker. This site claims that is was 500/cannon. That's just crazy.

AERONET GCE / IBERONET: Fokker D.XXI part 1 (Spain and Denmark))

Thanks.

Marcel · Feb 5, 2009

The manual claims a top-speed of 460 km/h at 5100 km/h at an engine speed of 2750 rpm. As far as I can determine, the prototype for the Dutch version had a top speed of 445 km/h at the first trial tests. Under pressure of the Dutch government, Fokker adjusted the a/c (streamlining) to get a top speed of 460 km/h at 5100m. They succeeded. This was of course a clean a/c without armament etc. The tests with 212 shows that after installing military equipment, the top speed dropped to 435 km/h.

I unfortunately now very little about the Danish D.XXI's. I was hoping to attract some Danish members to give some info on them.

Ruud · Mar 5, 2011

Hoi Marcel,
Great stuff on the Fokker and on May 1940.

My Oma told me that she was out hanging up the wash on the morning that the Germans attacked the Kooij. They lived in Breezand at the time. I grew up just a few minutes from the Kooij.

later
Ruud

rank amateur · Mar 14, 2011

Hi Marcel,

Great info. I remember reading a book about the subject about 30 years agoo. I thought by Hugo Hooftman but considering the time that has passed the name of the author could be wrong. Anyway,in the same series there was also a book about the G1 in may '40. These books are no longer in print so long live the internet and historians like you.

Chrzzzz

Marcel · Mar 17, 2011

Hoi rank,

De stichting Fokker G.1 zal dit jaar een boek uitbrengen over de G.1. Veel nooit gepubliceerde foto's en info. Een aanrader!
The Fokker G.1 foundation will publish a book of the G.1 this year. Many photo's and info that was never published before.

rank amateur · Mar 17, 2011

He, bedankt. Ik zal hun site in de gaten houden. Are you familiar with the books I've mentionned. I distinctly remember volumes about the D21, the G1, the T5 and the CV/CX but like I said, this was over 30 years agoo. Your memory tends to play tricks with you. Chrzzzz

Marcel · Mar 17, 2011

I think you're talking about the Nederlandse luchtvaart encylopedie. Yellow cover, red letters? They are well know and a good read, although slightly outdated nowadays. They are quite rare these days and many want to have them. Very expensive on the market. And you're right, Hugo Hoofdman wrote them.

Marcel · Mar 17, 2011

Ruud said:
Hoi Marcel,
Great stuff on the Fokker and on May 1940.

My Oma told me that she was out hanging up the wash on the morning that the Germans attacked the Kooij. They lived in Breezand at the time. I grew up just a few minutes from the Kooij.

later
Ruud

Hoi Ruud,

Did your grandmother see the 10-may dogfight? Did she tell you anything about it? I would like to hear/read about it.

rank amateur · Mar 18, 2011

Hi Marcel, I think you're absolutely right. I should check the public librairy. That was the place 30 years ago where I read those. In my opinion there stil is a market for those books. I wonder who owns the rights. Is about time for an 2011 edition.

Thanx

Ruud · Mar 18, 2011

Hoi Marcel,

She never mentioned seeing any fighting, but she did clearly remember planes flying to De Kooij. She said German planes, but i do not know how familiar she was with the aircraft types in the area. Like most of her generation, she spoke very little of that time.

My great uncle was killed during the fighting at the Grebbe line. He told his squad to get out of a "bunker" (not sure if it was a pillbox, bunker, or other fortified position) while he held off the Germans. When they looked back they saw an explosion in the bunker. Artillery? Satchel charge?

Another great uncle was picked to go to a work camp (my grandmother slaughtered a pig and that was a no-no, so he confessed to it). He got off the train and went into hiding in Friesland (IIRC). My Grand parents on my mothers side had a radio in the attic. They also hid their bikes on top of a shed. They had NSBers living across from them. Again, not much told to us, and they are sadly no longer with us to ask them for more.

Marcel · Mar 19, 2011

Ruud said:
Hoi Marcel,

She never mentioned seeing any fighting, but she did clearly remember planes flying to De Kooij. She said German planes, but i do not know how familiar she was with the aircraft types in the area. Like most of her generation, she spoke very little of that time.

My great uncle was killed during the fighting at the Grebbe line. He told his squad to get out of a "bunker" (not sure if it was a pillbox, bunker, or other fortified position) while he held off the Germans. When they looked back they saw an explosion in the bunker. Artillery? Satchel charge?

Another great uncle was picked to go to a work camp (my grandmother slaughtered a pig and that was a no-no, so he confessed to it). He got off the train and went into hiding in Friesland (IIRC). My Grand parents on my mothers side had a radio in the attic. They also hid their bikes on top of a shed. They had NSBers living across from them. Again, not much told to us, and they are sadly no longer with us to ask them for more.

Not surprising but a pitty. I've got the same problem. A family story is that my grandfather barely escaped execution as he was in the communist resistance, mainly involved with the De Waarheid/Noorderlicht. Unfortunately he passed away long ago when I was little, so I never could ask him. I'm now researching what really happened, as the family story sounds too fantastic to be true.

pauljos2001 · Feb 7, 2012

Marcel said:
According to my sources, no Dutch D.XXI was ever fitted with canons. All a/c had 4 LMG's. As Juha mentions, Finnland tried 20mm canons on the D.XXI and I believe the Danish AF did, too.

I am new on this forum and followed the great explanations about Fokker DXXI.
However some photobucket pictures are not visable any more.
Is it possible to renwe the link or post the pictures once more.

regards
pauljos

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