Fokker D.VII nose

[expositor]

Photo's show some D.VIIs with one or two "holes" beneath the radiator, and not shown on any plans I've seen. Increased air flow for the carb, or to cool the ammo? It/they don't appear to be universal. Any way to know which serial numbers were so modified?

Thanx,
Jim

[Jeff Brooks]

Hi Jim,
I have gone through my archive of historical photos that I have collected off the internet (Thank you Al Gore)

I have only found 4 aircraft that have holes in the chin cowl.
There may be more, but I don't have a picture of it.

1) Fokker Built 387/18 flown by Ernst Udet


2) Fokker Built 4253/18 also flown byt Ernst Udet


3) Albatros built 817/18 "Nickchen II"


4) OAW built 4453/18



Since the size and the number of holes is not consistent between the manufacturers (Fok, Alb & OAW), I believe that these holes were field modifcations made to correct overheating problems that were well documented.
Many pilots removed the upper engine cowling (like on Alb 817/18) to allow more air out of the engine bay as a possible fix for overheating.

[expositor]

Hi Jeff,

Thanks for posting; and I second the kudos to that internet inventor....I was familiar with the first three photos but not that last one, and never noticed the holes in the first one with Udet. I thought that they may have been field mods, but wanted the opinion of someone more knowledgeable than I.
Thanks again!
Jim

[Jeff Brooks]

I am just speculating on the holes in the nose were to correct the overheating issues on the original DVIIs.

I had to deal with similiar overheating issues with my DVII.
With the Ranger engine being air cooled, getting the air to flow correct required a bit of experimentation on my part.
I tried putting baffling on the top of the engine to force the air out through the louvers on the side engine panels.
I tried removing the top engine cowl on the right side to allow more air to escape.
I tried giving the oil cooler it's own exit with a baffel to create a negative air pressure behide the oil cooler.
None of these things worked.

What I discovered was that the overheating problem was pilot specific.
Some pilots never had an overheating problem, while others had to land early when the oil pressure would drop and the oil temp would reach the temp limit.

Because the aircraft doesn't have trim, you have to constantly keep forward pressure on the control column.
If you get lazy and allow the nose to raise, the aircraft plows along and the cooling air is disrupted.
Once I noticed this, the fix was to push the nose down and add power to get the correct airflow into the front of the plane.
Once the pilots did this, the temp would go down and the oil pressure would return to normal.

I wonder if the original radiators may have had something similiar to this.

[expositor]

Wow Jeff, I'm more than impressed. Thanks for posting!

Jim

[Jeff Brooks]

Hi Jim,
Just a thought, if you notice how the chin cowl in the picture of 4253/18 is all banged up ... I have a theory.


The nature of the aircraft balance of the landing gear when taxiing around makes it very easy for the aircraft to end up on it's nose.


And since the aircraft were designed to be disassembled when putting them on trains to move to the front, they needed a method to put the top wing on in the field.
When I assembled my plane in the front yard (and again when assembling the plane at Geneseo), I deliberately put the plane on it's nose to make it easier to lift the top wing in place with just a few people.
(By the way, in this position, the engine case vent becomes a oil drain ... ask me how I know)

In this picture I was able to install the top wing with just my wife, my daughter & her friend.



I believe some mechanics tried to avoid puting a load on the crankshaft by putting the weight on the chin cowl.
The thin aluminum caved in and they had to beat the cowl back into shape.
Without an english wheel to smooth the hammer marks out, the chin cowl looked beat up.

I have no proof, it's just a theory.

[Maxim08]

Jeff, I have photos, somewhere, of this and not just D VIIs. Seems to have been pretty common practise and with other aircraft as well. I’m sure Greg Van has images.

Regards,
John

[expositor]

Jeff,

Still impressed! When you mentioned a Ranger engine I was wondering how
an inverted straight six would fit in a replica D.VII. I see that it's upright and much closer to the German engines. Thanks for posting the photos.

Jim