Fokker DR-I "leading edge tape"

[Tim West]

After some discussion in other threads and looking for anything that might be the rosetta stone to tri plane finishes, I was focused on leading edges of the wings.

What I began to see was a pattern that became an obvious piece of the wings leading edge. At first it looked like a simple brush stroke to clean up the edge between the olive streaking and the light blue underside. The color is olive, though some have suggested black. The more I looked, the more the demarcation line looked too clean and consistent to be a brushed line. That led me to pose the question to Terry of whether or not the line maybe be tape rather than a doped line.

Based on a photo of Fok 513/17 wn 2130, Terry after discussing this with Dan-San offered the following:

"The wings were covered spanwise by a piece of fabric on the top and a piece on the bottom. The two pieces of cloth were probably laid on top of each other and a seam sown along the entire leading edge of the wing to give one piece which could entirely cover the wing. The fabric pieces were then reversed so the seam was on the inside and only the folded fabric faced forward. A tape was then stitched on the outside of the join to protect it from airflow and possibly tacked to the leading edge of the wing."

Terry, I hope you don't mind the quote.

Indeed if you look at the photos you can clearly see this tape. What is interesting besides the use of the tape, is that it does not seem to appear on early run planes. You do not see it on the F.I.'s or on DR-I's in the s/n range of 100-170. Also some unidentified planes exhibit this lack of demarcation, so perhaps their s/n range is with in this group. (w/n 1697-1882) ? Wonder why they made the change, which is seen widely in later run DR-I's.

Also there are those who feel that this is still just a olive line to clean up the edge between olive and light blue. This is what I originally thought, but I am leaning towards the possible use of tape.

What this all mean? Who knows. That's why I asked?

[Lucky Dog]

Tim,
Were there not some issues with Fokker regarding the quality of construction on early Dr1s that resulted in the fabric tearing loose on the upper wings? (I seem to recall there were problems with moisture causing failures in glue joints). Perhaps this was part of the improved wing.

[Elfen]

Originally Posted by Lucky Dog

Tim,
Were there not some issues with Fokker regarding the quality of construction on early Dr1s that resulted in the fabric tearing loose on the upper wings? (I seem to recall there were problems with moisture causing failures in glue joints). Perhaps this was part of the improved wing.

Several DR1's crashed before they were recalled for the wing replacement. I cant find my list of pilots hurt or killed, but I do remember Lothar von Richthofen survived his crash when the fabric of his top wing started to tear. But he suffered serious facial injuries which later gave him headaches and doubled & blurred vision.

[Langdon]

Originally Posted by Elfen

Several DR1's crashed before they were recalled for the wing replacement. I cant find my list of pilots hurt or killed, but I do remember Lothar von Richthofen survived his crash when the fabric of his top wing started to tear. But he suffered serious facial injuries which later gave him headaches and doubled & blurred vision.

Lother's aircraft, the one you refer to above, was a late built example Dr.I 454/17, so it had the improved wings.

Langdon

[Tim West]

Originally Posted by Lucky Dog

Tim,
Were there not some issues with Fokker regarding the quality of construction on early Dr1s that resulted in the fabric tearing loose on the upper wings? (I seem to recall there were problems with moisture causing failures in glue joints). Perhaps this was part of the improved wing.

Yes, it seems that a series of events resulted in top wing failures and the idflieg issued changes that included (relating to this topic) stitching of linen to the ribs rather than nailing. Most others are structural. No where does it mention anything about the leading edge linen. So.......? hmm?

If the leading edge was stitched and or tacked to the ply underneath, than it was done for another unknown reason.

The appearance of the edge tape.....or dark olive demarcation, depending on your view, began appearing at the same time Dr.I with improved wings were being shipped. Fok. 201/17 wn. 1920 was the first with improved wings.

Since I know of nothing specific, then I cant say if the edge change was aresult of Idflieg requirements, sub contracting or Fokkers own in-house design change.