Finally building wings from scratch.

[SpainCub]

Hey all, so I’ll start my build here shortly on all things SuperCub... I’m still debating several things before I make a new purchase of AL or spar blanks, unfortunately my 4 pairs of blanks got mistakenly removed by some fellows who thought it was a box I was trying to trow away, I guess they thought the same for most my tools and other scrap metals...


well, I have three sets of plans to follow with two options each...
Here are some practical questions I’d like to pose here....

1- metal wing or fabric covering? Outside of weight or the believe that the airfoil shape is better held on the all metal wing, which would you choose? I’d like to hear real use cases why one or the other....
2- Anyone flown a SC with a Taylorcraft wing (23012 airfoil)? I’d like to hear a PIREP from those flying regularly a cub then hopped on the modded wing?
3- Single Strut or Dual? Simple changes can go either way, a single strut will get me 7,5% faster from DRAG perspective, it also has the option to fold the wing, which was something I was considering...
4- Anyone flown a Dakota wing vs a Slotted (added) to a cob wing... thoughts there? I’ve flow on the Dakota wing but not a PA-18.... have not flown a Added Slot.
5- I plan to make this experimental November and take it to Alaska in 5 years time (more or less when it’s done and I’m free “€€€” wise.... I have seen a bunch of N Experimentals been borned in Europe, either as a prototype or the Solar Impulse for example... anyone have insight into this?

I look forwards towards posting some rib stamps as soon as Start to build the nose ribs. Will be sending the CNC files out to cut things out in DM then some metal parts....

TIA

 

[CharlieN]

If you are starting with forming the LE ribs then you have decided what you are building.
To me the materials the wing is built in has both to do with the type of labor you want to put in as well as the mission the plane is intended for.
For me I started my current project with just building similar to an original, in my case the J4. That would have been all wood structure as my J4 is.
But the planes I built in the past had a design goal of a 5:1 speed ratio. I found that achievable and realized that was a needed goal in my current design.
When considering airfoils, if you are building with a fabric surface do not even bother with a laminar flow profile. The fabric wing will not allow the needed spanwise flow needed to meet the goal. A laminar wing surface has to be accurate not just fore-aft but spanwise as well.

Being my build started as a wood spar and rib, fabric build I knew achieving the needed performance was not going to happen so I then designed with a composite top skin and LE. Fabric underside from front spar back. I could get the performance needed but do not want to invest in the massive amount of disposable tooling for a one off build.
I was also entertaining a single strut and the wood spar composite skin could be made torsionally stiff enough it again would eat to much resources to build.
So I ventured back into at first a metal structure and finally an all metal wing. The wing is now easy enough to build as a single lift strut.
I am utilizing a Riblett optimized airfoil, not one you would find in a Cub but closer to what one might find on an RV type aircraft. This moves the Cp aft to get the desired performance and let the LE slats and flaps do their stuff to allow the plane to slow down.
This is not the simplest build, but it suits my desires.

 

[SpainCub]

Thanks @CharlieN for the input. I agree that build to speck is one thing and I’m goin in different direction...

As for airfoil foils is concerned, let’s say I’ve gone that path for a long time, this might be my fourth set of wings been build, I’ve done all thus far in wood and a combination of buildup spar and composite ribs.... i’ve Been trying to uptimize build process more than anything there after. You might want to filter this out, but the first attemp was to build a Riblett airfoil, you can rearch the forums as see my post on that one... I can honestly say that there was nothing gained from the Riblett and I personally found that there was a better ( give or take a %) percentage in the Piper airfoil vs the Ribblet at High AOA. There is also a more abrupt separation of laminar flow and there really nothing gained on the high spectrum of the speeds.

I have build a more radical airfoil design wing (thanks @Jim_C)... let’s say that one is a lot more work in place but definitely would love to see it in the hands of some of the more experienced pilots.... drawback is cm a pitching moments require a serious rethinking that’s just throwinit on a cub or in my case a breazzy like design for testing.

For now all I’ve sent are forming blanks to be cut out of DMs, since I have to build a wing for my self and one for a friend, I figured I’d verify my CNC files on DM before... i might have to refine that before I press (hydroform) any ribs... so I guess I have time and will to go through another iteration of the build blanks.... who knows... I may build enough ribs for several planes... ? :roll:

I’ved moved away for composites for one single reason, they made more sense to design wings and airframes together to get the most out of the materials. Then there was cost... if you think like black metal, your costs are higher yet you don’t neseseraly gain much of the weight / structure... in other words you take a part, $_carbon / $_original part then to the same, weight_carbon / weight_old and if those % aren’t lined up, the the efforts are just not there call me silly but that is the way I function.

anyhow...All Metal? And feedback?

Thanks!!!

 

[mike mcs repair]

some rib making videos here

https://www.youtube.com/channel/UCD9Pbqxe_t9uK9EpukUvbng

 

[SpainCub]

some rib making videos here

https://www.youtube.com/channel/UCD9Pbqxe_t9uK9EpukUvbng

Thanks Mike, I’m following direction from the guys that run one of these.... https://youtu.be/RhG8gISbWMA

as the 2024-T0 solution is set to T3 they need to get pressed... right after squelching them... here is what it should look like... I need to cut some excess material as the strengthening emboss ( not sure it’s the right term) is added on the edges.



I’m shooting for full rib ( three piece rib) 0.032 at 6.5 oz... for comparison, an almost 3x cost composite rib was 6 oz... a piper original rib was 7.2oz my best wood full rib was 6.4oz. For the composite once the added parts where added to attach them to a metal spar, they where 6.2oz. not sure what the weight of the 23012 (Taylorcraft) airfoil will be at, it’s a little thinner at camber, 12% vs 12.4% of the Piper Rib.

 

[don d]

You are making it all too hard. Look at Carlson aircraft rib,spar and strut material

 

[SpainCub]

You are making it all too hard. Look at Carlson aircraft rib,spar and strut material

it depends, there are option at Carlson but all my needs wants are not covered....