Hi Franny,

Going back to the beginning of your thread, When you were looking at the slight size differences for makeing ribs 1-6, did you actually make ribs 1-6 progressively smaller according to where the dotted lines indicate the size? I have been measuring each rib on the build plans and the rib on the wing layout and they are not exactly the same size. I guess it wont make to much difference because I will probably half to trim each rib individually to fit if necessary anyway.

David

Hi David,

I think I trimmed them a bit too, but I think I started with the dotted lines. The key is to line up the spars. That is most critical. Then, adjust the leading and trailing edges to fit the profile on the plans. I slotted the trailing edge to accept the ribs. That actually makes it easier because you aren't cutting up to a hard edge. It is quite a bit stronger too.

Another consideration is the wing thickness. It should taper smoothly from root to tip and I had to sand in some areas and add more material in others to get that smooth transition from rib to rib. You'll need a long and flat sanding bar to help.

It is a bit difficult, but not super hard. The leading and trailing edges are parabolas and so is the thickness taper. You'll get the hang of it quickly, just keep the truss vertexes where the spars run nice and straight and it will fall in place. Oh, I think I noted that a couple ribs are just flat out wrong... Watch out for those...

f

I just got a closer look at the valkyrie that is pictured in post #11 (the last picture, the one with yellow wings) I noticed in that picture and others of it that the fuselage was not sheeted. I was under the assumption that the fuselage had to be sheeted because the plans call for it and it would give it more strength. Does the fusleage not half to be sheeted?

I'm not sure that it has to be sheeted, but it doesn't add much weight and it really adds a lot of strength. You can sheet or plank... It is a monocoque design so it carries the majority of its load on the skin as apposed to using a more rigid inner structure. If the covering was applied well and locked down and shrunk very tight, it would probably work well. A sheeted fuselage will still be more rigid and there will be less flexing and twisting. Not to mention I think the sheeted fuselage looks better. I think some will leave it uncovered to show off all the work that goes into the substructure.

Franny

It should be sheeted/planked if you want to compete in SAM contests.

I'm kind of sleepy tonight as I read through this whole thread last night. Franny - WOW!!!!

Owl

Franny, Can you tell me again why you decided to go with a double decker pylon floor in the fuselage. I am refering to the pictures in post 415. In the plans I have it just shows one floor. Does your actual pylon sit on the top floor or does it go down to the bottom floor as well?

Thanks again,
David

Hi David,

So, on the original plans, Goldberg calls for a single shelf to mount the pylon into and called out balsa as well. I think what your were to do was to finish the top sheeting and then mark the stringers location from the pylon on the top of the fuse and drill holes and glue into place with a "liberal" amount of adhesive. With such a big wing and all that leverage, I thought that adding a second shelf would help keep the torque off the surface and better help distribute it to the inner structure. I also upgraded the material from balsa to sheet bass wood. Since this is so close to the CG, I didn't worry much about the super small weight increase. That wing carries a lot of inertia and it all gets transferred into the fuselage through the pylon. I think the Valkyrie was one of the first, if not the first to use a pylon design (even before the term "pylon" was coined). I think it was just a first revision of the design and it could use a little extra buttressing.

So far, so good on mine...

Franny

The floors look much wider than the actual pylon so I am assuming you just glued the bottom of your pylon on to the top floor, is that correct or is your pylon somehow attached to the lower floor as well?


*Edit*

I see now from the pictures on your website that you must have drill or cut some holes in the top floor to allow the pylon posts to sit on the bottom floor.

Thanks David,

Yup. And then it was epoxied into place. Not my best gluing or drilling job, but it did work. the bottom pylon rib was also set at that time to match the contour of the fuselage. There is a lot of alignment that has to be just so when that sets. There are +2 deg incidence I think and the wing needs to be straight. It is a bit tricky. A jig would make things a lot easier. really, just something to prop the wing on each side while the glue sets would have made things easier.

Sorry to get back so late... Long weekend...

Franny

I came across another question about building the horizontal stab and vertical fin. The plans I have only show one rib for the horizontal stab and one rib for the vertical fin with a note that says "typical shape." The fins have an eliptical shape like the wings and everyone is a different size. How did you go about building the other ribs?

David

Hi David,

Yeah, that was an "issue" What I did was to scale them in PhotoShop so the spars would run parallel. I have the PhotoShop files if that would be of help to you. I think I made a different layer for each and then just printed them out at 1:1 scale so I could build to them.

Franny

I though I had posted the links a while back... Took me a bit to find them:

Here they are... Just click on the links. They are way too big to upload here so I uploaded them to my website:

http://www.frannybrodigan.com/H-Stab ribs-3.psd

http://www.frannybrodigan.com/Fin-Rudder.psd

http://www.frannybrodigan.com/Pylon.psd

f

Couldn't get the top one to work Franny.

Huh... It seems to have flown the coup... I should have it on my machine at home. I'll let you know...

Sorry about that...

f