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Go Back   The Aerodrome Forum > WWI Aviation > Aircraft > Replica Aircraft


Replica Aircraft Topics related to the construction of WWI replica aircraft

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Old 2 October 2008, 04:08 PM   #1
Tim Plunkett
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Fokker D7 wing kits

Guys, I have been in contact with William Scheunemann of Juneau WI about producing a D7 wing kit. He can provide the entire wings or a precut kit. He can provide spars. The more orders he gets the less the price for all. Is there anyone out there that is interested
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Old 2 October 2008, 05:14 PM   #2
Von Writter
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Quote:
Originally Posted by Tim Plunkett View Post
Guys, I have been in contact with William Scheunemann of Juneau WI about producing a D7 wing kit. He can provide the entire wings or a precut kit. He can provide spars. The more orders he gets the less the price for all. Is there anyone out there that is interested
I would be pending a price, and, not to speak for him but I bet Pavel would be too.
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Old 3 October 2008, 01:08 PM   #3
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Interesting post.
The questions are:
Whose drawings?
What specs re the lamination thicknesses on the spar tops and bottoms?
What rib profiles?
What's a kit? Pieces to build from? Finished wing?
Lot's of questions, but there is also a lot of conflicting information available to builders. I haven't met too many people yet who have actually handled and measured real D VII bits to provide the insight required for a project like this.
Would I like to be able to buy these parts "off the shelf"? Absolutely but only when I am confident that they will be correct.
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Old 3 October 2008, 04:21 PM   #4
Tim Plunkett
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wing kit

John, I was talking to him about the replicraft plans for the wing kit. He was willing to make everything except the metal parts. The set up is expensive and the more orders he has the cheaper he can make it for everyone. He quoted me a completed set of wings or a kit. The kit included every wood piece on the replicraft drawings including the wheel wing. If I get interest from others I will proceed if I do not I will not.

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Old 4 October 2008, 09:17 PM   #5
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Tim,
I spoke with Bill Scheunemann at EAA Airventure. He seems fully capable of producing the DVII wing kits. At the time, he indicated that 6-7 kits would spread the front end CAM (Computer Aided Manufacturing) coding costs of the design to a reasonable level.
As Maxim08 asks, Who's drawings? Jeff has had problems with wavy wings using the older Replicraft drawings. If I remember correctly, he had a fair amount of design work getting rid of the waves in the wing. Perhaps the newer/revised Replicraft drawings incorporate the corrected airfoil coordinates. Does anyone know?
Once the minute details of the wing design are verified, then it can be used as a source for CAM coding, but I am not sure we are there yet. Once that is done, the cost in $$ and time to build a D.VII wing set will be drastically reduced, but if it doesn't fit together properly it will be a huge problem.
Despite my concerns, I'm interested.
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Old 5 October 2008, 06:01 AM   #6
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If the wings are modeled in a solid, parametric modeling program like SolidWorks, all the uneven ribs will be worked out by its powerful lofting tools.
If it is created in the S/W environment, one can get some understanding on its structural elasticity by using S/W's finite element analysis, Cosmos. In that way, you have some insight on the structure's weak areas, if any, that could be bolstered up before any wood is cut.
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Old 5 October 2008, 06:41 AM   #7
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Troy had gone this route already. I personally think that spending all that money to laser cut ribs to the exact shape is a waste of money. It is so difficult to keep the shape absolutely perfect during the assembly. A jig & a router will be just as effective as a laser cutter in this instance. Save your money.

If you were interested in making a kit, you should consider making the assembly jigs instead. The jigs are where you need that kind of accuracy. I personnaly would have bought laser cut jigs that can be used to route the webbing, and assemble the ribs.

A while back, I got a quote from Neil Good for DVII wings, he wanted about $40,000. At the time, I thought it was insane. Now, after estimating the cost of the materials, using double the material cost to estimate labor, then add shipping to the cost ... $40, 000 is not too far off the mark. Neil has made several sets of DVII and other wings, and I believe he knows what he is doing!

The other things you need to factor into, when building the wings, is the knowledge gained by making a few sets. You end up wasting a lot of material figuring out the nuts & bolts of how to do it right. Having made some ribs myself, there are many issues that popped up while making them. Any mistakes, the builder has to eat financially.

Then there is the liability to consider. Yeah, the guy you are building the wings for accepts the risk, but his wife and kids might not if the wings fold in flight. As my wife said, you do these folks a favor and make them wings at a great price, and if anything goes wrong, we lose our house. That's is not a smart gamble. You need an A&P, lots of documentation, load testing of your work & several successful wings built to protect yourself from lawsuits. For a guy making oneies & twosies to make a buck, you really are hanging yourself out there.
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Old 5 October 2008, 08:58 AM   #8
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Jan. I absolutely agree that the wing needs to be solid modeled before it is released for production using a CNC system to produce the parts.

Jeff, I don't think you yet understand the implications of using a CNC router (not a laser) to produce the components. Assuming you have the geometry correct, you tell the computer controlled router what you want, fasten the appropriate stock in its cutting area and turn it loose. The accuracy is at least as good as what you get by routing around your form block and can be 3 dimensional. Assembly jigs are easily produced out of MDF board and when I saw Bill Scheunemann at EAA Airventure he showed me just such an assembly jig. The key difference is that the geometry will reside in a computer instead of a form board for a component. You still have to learn how to bend cap strips the old fashioned way. I asked Bill where he purchased his quarter sawn lumber he he said direct from the mill..??
With regard to Legal liability questions: The CNC router operator still has to select an appropriate piece of wood to make the part, and the builder still has to examine what is made and approve it for use prior to assembly. This required decision by the builder is a key point that isolates the supplier from liability. If the builder also signs off on an acceptance of the dimensions and agrees that the components are being built to his specifications, then that would provide a defense for those who develop the dimensions of the parts to be made. After all, we are trying to faithfully replicate something that was originally designed in WWI. If you want to avoid all risk of liability, you will have to stay in bed. The best you can do is to get good legal advice and purchase appropriate insurance.
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Old 5 October 2008, 09:18 AM   #9
Jeff Brooks
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I dont' doubt the accuracy of the CNC router or laser. I doubt it is worth the cost.
My experience making these ribs, has shown me that the assembly of the parts is where the error occurs. If the materials are cut exactly to the dimensions wanted, and the jigs are exactly where you want them ... there is still a little movement introduced when assembling the capstrip to webbing. The end result is the same as if you had made the parts by hand with a router over a jig. It is tough to justify spending more for the machined pieces, when the final product is the same as a cheaper method. You reach a point of diminishing returns.
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Old 5 October 2008, 10:27 AM   #10
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Jeff, What is the cost in time and money to build a set of accurate Fokker wing rib router guide and assembly jigs? How much would you be willing to pay for those?
Not intending to be argumentative, just interested in quantifying something that is otherwise difficult to quantify. I believe you have enough hands on time to come up with a reasonable guesstimate.
There is a lot more in building a wing of course, but that is a lot of the bull work.
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