Nose Rib Feedback

[Weldingiron]

I decided to practice flanging on one of my nose ribs tonight and was disappointed in the result. I haven't fluted the flanges yet but I can't seem to get them any less wavy than this by hammering. I don't plan on this rib going in the wings, but I am looking for feedback as far as how acceptable this would be to flute and ways I might improve. Thanks in advance!

[way_up_north]

I decided to practice flanging on one of my nose ribs tonight and was disappointed in the result. I haven't fluted the flanges yet but I can't seem to get them any less wavy than this by hammering. I don't plan on this rib going in the wings, but I am looking for feedback as far as how acceptable this would be to flute and ways I might improve. Thanks in advance!

Dear friend and fellow builder.....

Maybe I'm wrong and it's a trick of the light...

ok...from your picture..it looks like you didn't use enough c-clamps to hold your forms together....I use 2 vises and 3 clamps.....to hold those forms together....plus I move the clamps around as I'm working...the bolts and wing nuts offer little resistance ....they are there keeping the parts lined up

it looks like your forms are coming apart from the force of the hammer blows...your fold over should be crisp and very tight...hugging the curved edge of the form

the wavyness is fine and fluting fixes all that....

check this his guys technique....diffrent plane but I do what this guy does to form my ribs..ignore the part with the brass hammer
our ribs don't have the flange to the nose tip...I would also always have a small piece of wood in the viseto stop the rib from sliding down and
getting marked up by the vise....enjoy

YouTube vertical fin rib forming

https://m.youtube.com/watch?v=4SyIiT...k-RCk1yTKzsZ1A

[fairchild]

Todd---
On thing I see is that the bend line has many little flats beat into it from your hammer. You can use a dead-blow rubber hammer --- or a polyurethane faced hammer or a UHMW hammer.

Maybe the best tool is a "flow-former" tool from the tinman. (Tinmantech.com) https://youtu.be/vUNrxB7Vypk?t=39

It is a plastic cylinder that fitted onto the end of a rivet set shank. You can start by running it slowly down the edge to be turned---- and massage it over about 10-15 degrees on each pass. It wont leave any marks.

Also I got a few of the big beefy bessy woodworking clamps to help squeeze the form block and the back up block together so there is some compression between them near the
outer edge. The lower half (where I am NOT hammering) in clamped into a woodworking vice. (or two) My form block is doubled 3/4 MDF and same with the backing block.
Beef is good......

You will get a gradual curve to the whole part---- this will be removed by the fluts on the edge. ALSO--- definitely build the RV corner bending tool to do the last few degrees of the
flanges. It works wonders. I couldn't make it work without it.

Prevent those little dents--- use the RV tool to fine tune the bend to 90 Degrees--- and the rest is cake !

Keep in mind-- these are the hardest because the curve is the steepest---- all others are easier.

Tim

[Chris In Milwaukee]

My personal opinion that may vary a bit from others' opinions, but I think it's a good first article. The curve on the nose ribs is going to make impossible to bend the flange flat. It's going to be wavier than a bag of cheap potato chips. Fluting will stretch things flat and straighten those flanges out appreciably. Couple that with the Vans straightener and it should come out very nicely.

I do agree with the above post that you could benefit from better clamping. With only two holes, it offers a lot of opportunity for the material to move around and stretch as you are hammering the flange over.

Check out this thread:

https://bearhawkforums.com/forum/bearhawk-patrol-plans-build/21676-fluting-party

You'll see when I'm doing the nose ribs starting around post #3 that they are really wavy. Once the fluting begins, everything flattens out nicely. I fluted mine a little bit differently than other folks have, but the results are the same.

~Chris

[way_up_north]

My personal opinion that may vary a bit from others' opinions, but I think it's a good first article. The curve on the nose ribs is going to make impossible to bend the flange flat. It's going to be wavier than a bag of cheap potato chips. Fluting will stretch things flat and straighten those flanges out appreciably. Couple that with the Vans straightener and it should come out very nicely.

I do agree with the above post that you could benefit from better clamping. With only two holes, it offers a lot of opportunity for the material to move around and stretch as you are hammering the flange over.

Check out this thread:

https://bearhawkforums.com/forum/bea...-fluting-party

You'll see when I'm doing the nose ribs starting around post #3 that they are really wavy. Once the fluting begins, everything flattens out nicely. I fluted mine a little bit differently than other folks have, but the results are the same.

~Chris

As I was looking over your very well done rib party post...it got me thinking....why on this plane do we not have flanges at the end of the ribs so,we don't have to make L brackets. To attached everything to the spars....etc.....maybe I'm missing something...are L brackets stronger?

maybe it's to get perfect alignment in the jig in case the formers are off a little

[jaredyates]

As I was looking over your very well done rib party post...it got me thinking....why on this plane do we not have flanges at the end of the ribs so,we don't have to make L brackets.

I was thinking it was also because of the different lengths of ribs?

[way_up_north]

I was thinking it was also because of the different lengths of ribs?

I think you're onto something...with a hundred guys making a hundred slightly diffrent rib formers...I'm thinking the wing jig ensures any minor screw ups are fixed there by having L brackets that let you hide all your miss made rib sins....

when end I say miss made..I mean off by a 16 of an inch...here and there

[Chris In Milwaukee]

The attach angles (L-brackets) allow for up/down movement for vertical alignment, in addition to what Jared said: fore/aft movement. The stacked cap strips and spreader bars don't go all the way to the end on a normal installation, so the length differs depending on the rib position. Cap strips and spreader bars are 1/4" thick inboard, and go to as little as 1/8" as you go outboard. If you're doing a Patrol or an LSA, then there are no cap strips or spreader bars out there at all.

[Weldingiron]

Thanks, guys! Some great feedback all around. I made a second attempt this afternoon with additional clamps and I think the results are a bit better. I still had a little bit of a problem with the corners of the flanges coming off the form block where the backing block didn't cover, but will see after fluting and using the Vans tool how it comes out. On the topic of the Van's tool, is there any reason that a Bob-stick type device couldn't be used to finish the flanges instead of the Van's tool with similar results? Thanks again for the words of advice!

[Chris In Milwaukee]

The Van's tool is a simple lever that bends the flange flat to -13 degrees, and then with the springback pretty much ends up vertical. It's a beautifully simple device to construct, it's consistent, and you don't end up with Popeye forearms like you would if you attempted to do the same with a Bob-stick

[fairchild]

Todd--- you can try watching this--- https://youtu.be/FP0PWK9orcQ?t=2
if you skip to the last 1/3 you can see the straightening tool and what it looks like. Everybody prob. makes them a little different--- but the function
is the same. I left the handle a bit long- (2x2 oak) and it gives the thing a little momentum and gives you some "bump" to help set the bend. When you make it you have to sand
the angle to be about 7 or 8 degrees past 90 to account for spring back. I had to test and re-sand a couple of times to get it where it left the corner metal exactly 90 when done.
Both working surfaces are oak so they don't deform too much with use.

now that I have made the nose ribs- I think it would be WAY to hard to bend flanges in the ribs and be able to hold accuracy good enough that when it was time for all the ribs+spars
to go together that they were EXACTLY right and all the same. I think you need to have them float right up until you have to decide where to drill the rivet holes.

Another mistake I made-- was when I cut the backup block that sandwitches the metal against the rib form---- I just traced the rib form block--- and took off about 1/8 and cut it there.
The 1/8 was to give me room to get my rubber hammer onto the curved bend line. And it did do that----- but--- here is what I noticed----

On the top front flange area--- the forward 3 inches or so--- is where the rib has the most curve. That means the bend line there has the most compound-curving to do. In order to do that
(and not be a mess) the aluminum there has to stretch a little in order to compound. In order to stretch-- it has to be held down very firmly in the immediate areas around the stretch.
This is where the back-up block needs to pinch the sheet tightly. I accidently cut the edge of my block back too much there so that it was unable to pinch right up to the start of the bend
line. (that 3 inch long area) I would say keep your block to within 1/16 of the start of the bend line there and use several heavy built clamps there for compression. You might even
try some powdered rosin there to get more traction. (?)

I see on your ribs the same problem my mistake caused. Front 3 inches--- just on the inside of the bend line--- you see a little canoe shaped deflection--- like a bent belly---
and that is there because when you were hammering that section--- because it needs to stretch there--- if the sheet can slide laterally in response to what you are doing to it--
it will slide INSTEAD of doing the compound stretching. The compound stretching used up the extra material that cant escape. If you LET it escape by not pinching it hard enough---
the extra material that didn't get eaten up during the compounding--- that material just moves over next door. That running trough along side the inside of the bend line is that slack.
That was supposed to have been IN the compound bend there. Several other people have dad that same problem too. I think the other areas of the rib where the curve is way less--
you can cut your back-up block back further and be OK. I tried to explain that on the video but I think I did a poor job probably.

T

[Weldingiron]

Thanks for that video; there is a lot of good information in it! I will definitely be using a straightening tool.

[Weldingiron]

As far as the lightening hole flanges are concerned, I've played around with the Bob-stick method and I can't seem to get truly uniform flanges. I know the rubber and hydraulic press method would yield better results but my work space is limited and I'm having a hard time justifying the money and work space required for the hydraulic press if the flanges produced by the Bob-stick (though slightly wavy and less aesthetically pleasing) are sufficient. Aside from the additional workout provided by flanging them manually, is there any benefit to the hydraulic press other than aesthetics?

[Chris In Milwaukee]

My Bob-stick samples were crap, to be blunt. I never figured out how to do it well within my boundary of patience.

[marcusofcotton]

As far as the lightening hole flanges are concerned, I've played around with the Bob-stick method and I can't seem to get truly uniform flanges. I know the rubber and hydraulic press method would yield better results but my work space is limited and I'm having a hard time justifying the money and work space required for the hydraulic press if the flanges produced by the Bob-stick (though slightly wavy and less aesthetically pleasing) are sufficient. Aside from the additional workout provided by flanging them manually, is there any benefit to the hydraulic press other than aesthetics?

The biggest plus for the hydraulic press is having it for all the other repairs, fabricating, etc. in the life of a doityourselfer.

[Weldingiron]

Take two! This is my second attempt. It's closer, I think. However, I don't like how wide the flutes from the new pliers are.