Clear as Mud - Fwd Fuse Structure

[WingsOnWheels]

I'm not 100% sure I am reading the plans correctly and need a double-check. I am assembling the lower longeron and the other bit of angle that runs from the F-604 to the lower engine mount. As far as I can tell, the lower longeron butts up against the flange on F-604 and the F-6101 ties it all together along with the 3/4 x 3/4 x .125 angle.

It also looks like the forward end (at the engine mount) of the 3/4 x 3/4 x .125 gets a portion of the angle cut off and then attaches to the outside of the mount.

Here are some pictures, does this look right?

 

[AMURRAY]

It has been a long time

Yes the lower longeron butts up to the 604 and the 3/4 angle gets a portion cut off. The lower longeron gets attached to the 604 with a gusset on the inside of the fuselage. It looks like you have a 6A so it will have a large gusset compared to the picture below which is a 6. The 604 bulkhead is the only bulkhead that is not plumb. The measurement from the firewall to the 604 at the top and bottom are different. The measurement is critical for setting the wing incidence.

 

[WingsOnWheels]

Great, sounds like I am going in the right direction then. Right now I have the 604 bulkhead clamped in place at the correct measurements from the firewall. Thank you!

Question for the 6A builders: I noticed that the F-6101 gusset as supplied by Vans does not match the angle between the lower longeron and the other cross member exactly. When I see parts from the factory that aren't quite right it makes me wonder if I have something set-up wrong. Even the plans show that the gusset isn't a perfect fit. Is this right? Why even send a pre-cut part if isn't just right?

 

[noelf]

It was a LONG TIME AGO...

...but it seems that the angle sides need to be flush with the firewall sides. This is so the front side skins will lay flat against the angles and the firewall flange.

When I fabricated my F-6101 plates, they were just provided as rectangular plates. They had to be trimmed to fit. I would think that any variation in different builders assembling this section would account for minor variations in what is needed for an exact fit.

 

[WingsOnWheels]

I would much rather have had the F-6101 come as stock so I could cut them to fit. Unfortunately, they came pre-cut but don't fit quite right. I am just concerned that I have something wrong that is causing the misfit. If I determine that my assembly is right and the F-6101 is wrong, I might re-make it out of stock.

...but it seems that the angle sides need to be flush with the firewall sides. This is so the front side skins will lay flat against the angles and the firewall flange.

When I fabricated my F-6101 plates, they were just provided as rectangular plates. They had to be trimmed to fit. I would think that any variation in different builders assembling this section would account for minor variations in what is needed for an exact fit.

 

[WingsOnWheels]

Ok, I have checked my assembly over and over again and everything looks correct. However, the F-6101 as provided by Vans isn't even close to a correct fit. I still have that nagging voice in the back of my head that isn't sure if it is the part or my assembly. Can any other 6A builders with a newer kit verify if they had this same problem? The supplied F-6101 is so far off, I can't resonably trim it to fit. Unfortunately, I don't have enough scrap 0.063 around to make two new gussets. I'm going to call Vans tomorrow to see what they say about this.

Here is a picture of me holding the F-6101 up next to the forward fuselage structure and lower longeron. I have the aft egde of the gusset up against the false spar to keep it square. You can see that both angles are off by quite a bit.

 

[noelf]

I'm not sure if you are showing the position...

...of the F-6101 plate on the "outside" of the structure just for the photos, but the F-6101 nest "inside" the aluminum angles. That will buy you a bit more material to work with. You are probably looking at Drawing #31.

Also look at Drawing #95. This drawing shows the F-6101 nested inside.

Also look at Drawing #46, Section C-C'. When it comes time to attach the tank Bracket F-696, you will fabricate a 1/8" spacer to fill in the gap between the forward skin and the F-6101 in the area where the F-696 bracket will be placed and drilled / bolted.

 

[noelf]

Colin...

...your tag line indicates you are building a -6. The F-6101 plate is only used on a -6A. You are building a -6A ... right??

 

[WingsOnWheels]

Yes, I just held the F-6101 on the ouutside for the purpose of the pictures, I understand that is goes on the other side. I just couldn't get a good shot in that position. I am building a 6A, I'll update my signature.