My Fokker DVII Project

AchimEngels · 2 July 2006, 01:08 AM

Hello Jeff,

sorry I forgott to look for the spacing of the rivets on the Swiss drawing. I´ll do so later.

If you have used the correct or close to correct sizes of the tubings for your control surfaces you will end up with the correct weight. The different steel qualities do not have a big influence in weight, since the weight of steel, regardless of its strenght is almost the same. In fact the avarage metal worker even says it is the same, so close they are.

I am talking from memorry here since all my information is at the workshop, so if I am wrong, just jump in and correct me.

The main frame of the D.VII stabilizer is made from 35mm outer diameter tubing with a wall thickness of 1mm, the front leading edge tube is a 14mm tube with 1mm wall and all the ribs are made from tubes of 0,5mm wall thickness.

The spars of rudder and elevator are of 30/1 mm tubings with ribs of 8/0,5mm.

If you did not use 1mm wall thickness tubings for all the ribs then you certainly are close to the original weight.

The pieces are pretty light in weight!

wolfenbill · 8 July 2006, 09:30 AM

Beautiful work Jeff. It's good to see a lot of Fokker projects ongoing.

gipsymoth236k · 9 July 2006, 01:28 PM

Achim,

I know that it is quoted as being probably too thin for today's safety, but isn't it documented that the original Fokker D.VII's 35mm diameter horizontal stabilizer tube was of 0.5mm thickness, and not 1.0mm?

Regards, Gary

AchimEngels · 9 July 2006, 09:37 PM

Hello Gary,

I am not sure on that one. I do not seem to know the source you may have to say it is documented.

I have no original Fokker drawing for the stabilizer and reffer to McCook field report ADM 467, which was also quoted on the wing spar discussion.

The report includes very detailed meassurments of the cut stabilizer frame including the wall thickness. The figgures are given in inches and I converted them to about 1mm, if I recall correctly. I may have to double check that again.

However, the Swiss documents for the D.VII in post war use, give a maximum weight for the stabilizer of 6kg while being uncovered.

This is what my stabilizer weights. Actually it weights 6,2 kg

, but this hardly enough difference to say the tubing should be 0.5mm.

But then again, the Idflieg type test documents give the total weight of the tail feathers including control cables and covering with 15 kg, while all the Swiss components together weight 17 kg. So there is a discrepancy of at least 2 kg which may indeed call for different wall thicknesses used in post war D.VII planes.

Could you quote your source here?

Thank you.

Cheers!

Achim

gipsymoth236k · 11 July 2006, 05:01 PM

Achim,

Yes, I recall an American test report from my research archives which includes pictures, and concerned the failure of a captured D.VII's original 35mm diameter horizontal stabilizer tubing, stating that it was found to have only a 0.019" or 0.5mm wall thickness, and the report also suggested that this size tube should be designed to be about double the failed specimen's wall thickness, or about 0.039" or 1mm.

If interested, I can find the report, unless someone else beats me to it.

Regards, Gary

AchimEngels · 11 July 2006, 09:03 PM

Sure, I am sure Jeff also would like to see it here.

If it is the ADM 467 report, then I am just happy to have made the "mistake" of making mine from 35/1mm tubing

Cheers!

Achim

Jeff Brooks · 12 July 2006, 10:46 AM

I'd love to see this report!!!!!

Makhpiyaluta · 12 July 2006, 12:03 PM

Jeff,

I haven't reacted on your thread yet but I followed it and I have to say you do a nice job

. I'm looking forward to see your D VII in it's full glory.
Keep up the good work!!!

Willem

gipsymoth236k · 12 July 2006, 12:50 PM

Quote:

Originally Posted by AchimEngels

Sure, I am sure Jeff also would like to see it here.

If it is the ADM 467 report, then I am just happy to have made the "mistake" of making mine from 35/1mm tubing

Cheers!

Achim

OK guys, will do! I'm away from home for a couple of days, but I will be able to scan the report and post it here soon.

Later, Gary

Jeff Brooks · 12 July 2006, 08:21 PM

Today I worked on the bracing wires.
I used the ferrules Ed Borkoski sent me. Ed's ferrules needed to be squeezed flat, after many attempts, I finally did it. it took ruining a few to get it right!!!!

I can only use these ferrules on the 2mm wire as the size does not match up with the thinner wire. So, Maximum08 & I went in on ferrules from a spring maker at a reasonable price. Once I get these ferrules made of thinner wire, i'll do the rest.