Trailing edge False Ribs

[Scott]

Good day All

In the process of assembling my wings. Just finished installing the aileron bay panels and realized I was missing the two small compression struts that go from the outboard aileron bay panel to the rear spar.

Was looking at the Taylorcraft Wing drawing to confirm the position of said strut and noticed it shows 6 false ribs (between the rear spar and aileron bay panels), one in between each main rib.

There were no such false ribs on CF-CLR and never were (as evidenced by the absence of any marks on the back of factory spars).

I'm assuming this is yet another example of a production change at the factory for which there is no available paper amendment, but wondering if anyone has seen a wing with these parts in place and or when they were discontinued.

I have the hand drawn sketch titled "Taylorcraft BC12D Series Left Wing Panel With Metal Stamped Ribs" and there are no trailing edge false ribs shown. There is no information on where this drawing came from however, though I have no reason to believe it is not accurate.

Thoughts? Additional Info?

Thanks for your help
S

[Mark Bowden]

Re: Trailing edge False Ribs

Hi,

It may be that the drawing you have represents an riveted rib wing? Here is a picture of mine (1945) when Dad recovered it. There are interbay L-stringers between the spar and aileron cove, upper & lower. They do not have a diagonal brace or vertical components like at the rib wing stations.

There are stamped ribs in this wing from a repair in the early 50's when a flight school had it. I"ll see if I have a better photo this weekend.

Mark

[Robert Lees]

Re: Trailing edge False Ribs

Scott, can you post a picture (photo?) of the drawing to which you refer?

I do have a copy of a wing drawing (drg number undetermined but revision Q dated 2/14/48) that I in turn, can cross-reference.

Rob

[Guest]

Re: Trailing edge False Ribs

Are they made of steel or aluminum?

[3Dreaming]

Re: Trailing edge False Ribs

I have a set of uncovered stamped rib wings here. The only brace on it is in the outboard section where the aileron cove tapers down at the tip. I think the wings with built up ribs had the braces, especially if they were 13 rib wings.

[Scott]

Re: Trailing edge False Ribs

The drawing I have is a larger version of the one in the BC12D service manual. It's the only wing drawing I've seen that appears to be a copy of a factory original. It's not complete by any means but that seems to be the standard for Taylorcraft factory drawings.

It looks to be for the stamped rib version, but it may have been adapted from the truss rib version and they simply forgot to erase those aileron bay struts.

[Scott]

Re: Trailing edge False Ribs

Hi,

It may be that the drawing you have represents an riveted rib wing? Here is a picture of mine (1945) when Dad recovered it. There are interbay L-stringers between the spar and aileron cove, upper & lower. They do not have a diagonal brace or vertical components like at the rib wing stations.

There are stamped ribs in this wing from a repair in the early 50's when a flight school had it. I"ll see if I have a better photo this weekend.

Mark

Thanks Mark
Looking at your photo it seems clear that the drawing is at least in part representing the truss rib wing. However you can see the detail view at lower right clearly depicts a stamped rib.

Not at all concerned about this, just curious. The way those struts were just nailed to the top of the spar tells me they simply added weight! So I'm glad they were deleted from production in the stamped rib aircraft.

[Scott]

Re: Trailing edge False Ribs

I have a set of uncovered stamped rib wings here. The only brace on it is in the outboard section where the aileron cove tapers down at the tip. I think the wings with built up ribs had the braces, especially if they were 13 rib wings.

Thanks
Have a look at those braces, I bet the nails are bent over and the flange of the L section is cutting into the back of the spar. No biggie but not really ideal. I made a couple of rib-inspired versions and installed them today.

[Guest]

Re: Trailing edge False Ribs

Hi Scott and all,

I would not believe anything about what is not in that drawing.

Absence in that drawing does not mean the part is not actually in the plane.

Here is why I say that; count the aileron hinges, I see two not three.

Dave R.

[Guest]

Re: Trailing edge False Ribs

Checkout page 16 upper left of the 1985 Taylorcraft parts manual in the tech. resources section.

Part number 1715 is what you are talking about (I think) and it gives a helpful description. Maybe I am behind the discussion and you already saw this.

I do not see that part in the pre-war parts manual at the same tech. resources section.

[Scott]

Re: Trailing edge False Ribs

Yup, clear on that piece
What was confusing is the depiction of 6 other struts or ribs between each main rib in the Aileron Bay area, shown on the factory drawing.

Another factory inconsistency. We have so few drawings, and apparently we need to view each as not telling the real story.

[Robert Lees]

Re: Trailing edge False Ribs

My drawing shows all those false ribs, but as 3Dreaming says, my stamped-rib '46 also only has the one towards the tip where the aileron cove tapers.

Rob

[Guest]

Re: Trailing edge False Ribs

My drawing shows all those false ribs, but as 3Dreaming says, my stamped-rib '46 also only has the one towards the tip where the aileron cove tapers.

Rob

The parts book I referenced (1985)only indicates one also and I think that mine (1946 bc12d) only has one like yours does.

[3Dreaming]

Re: Trailing edge False Ribs

I'm not certain without doing more research, but there may have been a design change in the aileron cove itself. I don't remember the pre war cove having the bead rolled in and the edges folded over and riveted. I think the older ones may have just had a flange with a broke edge. If that is the case that would be the difference between needing the braces and not needing them.

[Robert Lees]

Re: Trailing edge False Ribs

That would certainly make sense.