Hi All,

Interesting comments! Sorry for bring this back up after almost a year after the debate, but I was looking for user inputs on Rag vs Metal Wings.

BTW, please read this quantitative validation of Rag (purposely using that term ) vs Metal wings on the comments of better airfoil utilisation: https://ntrs.nasa.gov/search.jsp?R=19930081179

If you believe the research (:)) then you will see that the difference is practically negligible, or in fact, in favour of the Rag wings...

Mr. Maule and Dr. Koppen ( tied to Ford Motor metal division) where all solving problems of the times, lower life of the covering materials and planes been exposed to the elements. This made Metal wings a more attractive solution in the design process.

In retrospect, looking at the AD database, you will find an overwelming divergence of the result, metal covering designs suffering from more issues of corrosion (timely since there was no prior data or consensus of people leaving their airplanes out of shelters because of metal wings.) Functionally weight and flight develop of a design performance has an more important impact in the design decision, where MTOW <5000 AND/OR Vc <180knt/h are open to Rag covering where anything higher usually goes in favour of metal wings, yes there are exceptions and I have visited Oregon and the H-4!

I personally decided Rag covered wings because of cost/ease of build for homebuilders and hope to get to 150 Vc on my STOL design.

Thoughts?

I'm building a Bearhawk, which like a Maule, has all-metal wings like a Cessna. I think that's pretty cool, especially since for the Bearhawk, it's designed to use a single lift strut.

For the Pacer though, and by extension other classic rags like the Stinson 108, I think that metalizing is sacrilege. It also makes rigging your washout prone to wrinkling.

SpainCub wrote:Hi All,

Interesting comments! Sorry for bring this back up after almost a year after the debate, but I was looking for user inputs on Rag vs Metal Wings.

BTW, please read this quantitative validation of Rag (purposely using that term ) vs Metal wings on the comments of better airfoil utilisation: https://ntrs.nasa.gov/search.jsp?R=19930081179

If you believe the research (:)) then you will see that the difference is practically negligible, or in fact, in favour of the Rag wings...

Mr. Maule and Dr. Koppen ( tied to Ford Motor metal division) where all solving problems of the times, lower life of the covering materials and planes been exposed to the elements. This made Metal wings a more attractive solution in the design process.

In retrospect, looking at the AD database, you will find an overwelming divergence of the result, metal covering designs suffering from more issues of corrosion (timely since there was no prior data or consensus of people leaving their airplanes out of shelters because of metal wings.) Functionally weight and flight develop of a design performance has an more important impact in the design decision, where MTOW <5000 AND/OR Vc <180knt/h are open to Rag covering where anything higher usually goes in favour of metal wings, yes there are exceptions and I have visited Oregon and the H-4!

I personally decided Rag covered wings because of cost/ease of build for homebuilders and hope to get to 150 Vc on my STOL design.

Thoughts?

Oratex! Oratex!

....

Well, that's a lot of research right there!

Honestly, I'm looking at this more from a design POV; rather than peoples believes or just plain favouring one over the other as a matter of taste.

To keep the conversation constructive, let's all concede that there is no perfect solution, each has it's own limitations.

What I was hopping to get to is, form the professionals, the real bush people, and those that pretend to be on one the weekends, what is your preference and specifically is possible, what shortcomings are you trying to avoid vs the alternative. I'd like to get feedback as I can go either direction at the moment, id like to know what am I designing agains.

I know it's not the OP's topic, but if needed, I can start a new thread instead... And wait until I start asking about round or square tail feathers...

The basic construcion of a wing that’s designed from the git go to be an all metal wing, such as a Cessna wing, is often quite different than a wing that was originally designed as a fabric wing, then metalized, such as the Maule wing.

Is one better than the other? I don’t think so, but, for example, Cessna wings were designed for a single strut, vs two, which changes load paths, etc.

Design it right in the first place and should be good either way.

Would I personally metalized a fabric wing? No. Why? Because it will wind up heavier.

MTV

I’m restoring a Pacer now....on the wings. If there was an STC for metalizing w/ 0.020” 2024T4.....13 rib wing/s using Univair ribs....flush rivets an what not....I would have gone that route.....due to a few modifications....like moving the ailerons out and filling the void with longer flaps...87”

If the options involved a skinned plane or a fresh version of moderns fabrics I would pick the fabric plane everytime. The reality on the market is its real hard to find a nice plane with fresh fabric(Stinson anyways). Most are thirty plus years old and due for a complete recover. I didn't and don't have the time to dedicate. The very minor shortcomings of metal on a Stinson didn't really affect my needs negatively.
Like I said before,noise,washout wrinkle and about 40 pounds on an already heavy plane. That's about it.

mtv wrote: The basic construcion of a wing that’s designed from the git go to be an all metal wing, such as a Cessna wing, is often quite different than a wing that was originally designed as a fabric wing, then metalized, such as the Maule wing.....

I'm not so sure I go along with the second part of that statement.
A lot of people assume that the Maule wing was originally designed to be fabric covered,
mainly because they're fitted with two wing struts.
But I believe all the production Maules starting with the M4 (way back around 1964) had metal covered wings.
My own thought is that maybe the reason two struts were part of the design was to simplify rigging.
Anyone who's ever rebuilt a set of Cessna wings (esp without a jig to guarantee the washout is correct) might agree.

hotrod180 wrote:

mtv wrote: The basic construcion of a wing that’s designed from the git go to be an all metal wing, such as a Cessna wing, is often quite different than a wing that was originally designed as a fabric wing, then metalized, such as the Maule wing.....

I'm not so sure I go along with the second part of that statement.
A lot of people assume that the Maule wing was originally designed to be fabric covered,
mainly because they're fitted with two wing struts.
But I believe all the production Maules starting with the M4 (way back around 1964) had metal covered wings.
My own thought is that maybe the reason two struts were part of the design was to simplify rigging.
Anyone who's ever rebuilt a set of Cessna wings (esp without a jig to guarantee the washout is correct) might agree.

Look at an early Maule. Now look at a Piper Pacer. More specifically, look at the respective wings, as in their construction.....other than cover.

MTV

hotrod180 wrote:

mtv wrote: The basic construcion of a wing that’s designed from the git go to be an all metal wing, such as a Cessna wing, is often quite different than a wing that was originally designed as a fabric wing, then metalized, such as the Maule wing.....

I'm not so sure I go along with the second part of that statement.
A lot of people assume that the Maule wing was originally designed to be fabric covered,
mainly because they're fitted with two wing struts.
But I believe all the production Maules starting with the M4 (way back around 1964) had metal covered wings.
My own thought is that maybe the reason two struts were part of the design was to simplify rigging.
Anyone who's ever rebuilt a set of Cessna wings (esp without a jig to guarantee the washout is correct) might agree.

Here is the partial reason for the dual struts, the usage of the airfoil meant that you need to account 1%-30% of lift weight as you decrease the AOA from 0 toma negative value. This means that leveraging tooling and spar placement would dictate a structural need for second strut.

Once you commit to this, you can’t make the change.

Have a looke at the Luscombe solution to this, or even the new Rans 21 implementing a means to anchor s single strut to balance the loads over the two spars.

Mr. Maule was solving for a longevity need and some security concern at the time from the materials used to cover wings then.

Other than that, pretty much you cen go either way on a Maule wing...

From a design concept, if you design correctly, there might be an opportunity to have about equal weight on metal vs Rags... most of the weight savings comes from lighter spars or even a single spar on a new designe...

Having said that, has enybody calculated loads a Cub or Maule can really handle?

mtv wrote:....Look at an early Maule. Now look at a Piper Pacer. More specifically, look at the respective wings, as in their construction.....other than cover.

I'm just saying you can't always judge a book by it's cover.
I've never seen an unskinned Maule wing, also never peeked inside a Maule wing through inspection covers--
so I don't know if it is the same as a Pacer wing or not.
Does the Maule wing structure have all the same internal bracing (drag / anti-drag wires, etc) as doe the Pacer?
Or is it more like a metal Cessna wing, which depends on the metal skin to add rigidity?

hotrod180 wrote:

mtv wrote:....Look at an early Maule. Now look at a Piper Pacer. More specifically, look at the respective wings, as in their construction.....other than cover.

I'm just saying you can't always judge a book by it's cover.
I've never seen an unskinned Maule wing, also never peeked inside a Maule wing through inspection covers--
so I don't know if it is the same as a Pacer wing or not.
Does the Maule wing structure have all the same internal bracing (drag / anti-drag wires, etc) as doe the Pacer?
Or is it more like a metal Cessna wing, which depends on the metal skin to add rigidity?

Here you go!

Looking at the Piper Vs Maule wing, there is a strong business decision been made:

1. Look at the market, at that point everyone was going metal... they did it and where successful
2. They moved to an extruded part for the spar conforming the wing, this meant that they could easy save weight, increase gross and cut handling cost all at one go. This type of wing been metal is a lot easier to build, once the skins go on, you paint and install.

This allowed for further refinements like hydroforming wings ribs, lighter and lower cost once more. Morden CNC manufacturing design allows for cut-push-mount with more quality control and automated process. Keeping the original Taylor spars has meant that Piper uncured more cost in manual labour later on when the cost of skilled labor market became more competitive for skilled personnel and wages rose. For Maule, less manual post process of parts has been very positive.

Can you fabric cover a maul wing? Certainly looks doable... but I believe that Vnc is higher so most likely you need to consider in the flight develop you might be close to maximums of fabric tear tolerances... there is a design implication as well that should not be overlooked.

Rans says they had to shorten the wings on the S-21 to permit them to go with one strut.

I agree with Spain Cub, there are differences in the construction of the early Maule wing and the Pacer wing, but frankly, there are more similarities than differences.

MTV

mtv wrote:....there are differences in the construction of the early Maule wing and the Pacer wing, but frankly, there are more similarities than differences.

Yes, they both have spars and ribs.
Note the absence of drag / anti-drag wires etc on the Maule wing structure.
That is what is under most of all "metalized" ragwings.
Maule doesn't have them.

BTW my favorite uncle who was an A&P back in the early 1950's had a whole different take on what "metalized" referred to.
Back in the day, that meant that a part had been sprayed with molten aluminum.
Such as the Luscombe exhaust parts sold by WagAero: "A-513 steel with extended-life hot aluminized finish".

hotrod180 wrote:

mtv wrote:....there are differences in the construction of the early Maule wing and the Pacer wing, but frankly, there are more similarities than differences.

Yes, they both have spars and ribs.
Note the absence of drag / anti-drag wires etc on the Maule wing structure.
That is what is under most of all "metalized" ragwings.
Maule doesn't have them.

BTW my favorite uncle who was an A&P back in the early 1950's had a whole different take on what "metalized" referred to.
Back in the day, that meant that a part had been sprayed with molten aluminum.
Such as the Luscombe exhaust parts sold by WagAero: "A-513 steel with extended-life hot aluminized finish".

Drag anti drag wires are itty bitty parts. Look at the Spars, and Compare them to a Cessna spar. Those are PARTS.

MTV

mtv wrote: Drag anti drag wires are itty bitty parts. Look at the Spars, and Compare them to a Cessna spar. Those are PARTS.

Enough itty bitty parts and the weight adds up.
Since they're not needed for a metal-covered wing, that's why Maule apparently left them off.
Hence my comment about Maule wings being different than Pacer wings.
And BTW please remember we were talking about Maule wings vs Pacer wings, NOT Cessna wings.
You wanna look at a beefy spar, check out an RV6 spar, esp where it slides into the fuselage.

hotrod180 wrote:

mtv wrote: Drag anti drag wires are itty bitty parts. Look at the Spars, and Compare them to a Cessna spar. Those are PARTS.

Enough itty bitty parts and the weight adds up.
Since they're not needed for a metal-covered wing, that's why Maule apparently left them off.
Hence my comment about Maule wings being different than Pacer wings.
And BTW please remember we were talking about Maule wings vs Pacer wings, NOT Cessna wings.
You wanna look at a beefy spar, check out an RV6 spar, esp where it slides into the fuselage.

MTV is correct, all you need to look at beyond just the small details, they are very similar in design. Just to clarify two points I was trying to make:

It’s the choice of the airfoil and how the CM moves along the delta of Alpha (AOA) and the choise of wing attach points and consequently the spar location that dictate the dual strut.

The Maule and the Pacer wings are built on the same principle, so very similar, hence my point befor that you could mostly take a maule wing and cover it...

Mostly is a simple meas of sales yes but.... and in this case the but is anti drag wires, which considering that that all weighs could mean very similar weight vs a pacer wing. Now on a super cub, Piper original wings weigh ready to put on the strut 85-90lbs with paint.... what does a Maule wing weight? Btw that is a question not and affirmation... btw, since I do not know all the details of the maule wing, it could be that there is some stress in the skin/rib tomcount drag. If the ribs are thick enough, they might do the trick... “might.”

@MTV the issues with Randy’s design for the outbound was airfoil and spar type/locations. He was looking at ease of build and weight hence adding the truss between the spars to add a single strut. This meas as he build the arm out with a longer wing, then this moments on the truss increase substantially and minimizes the return on the original design concept.... it’s not necessarily a trade off but more of cause and effect scenario, faster plane single struted and higher wing loading or lower wing loading and slower plane because of dual struts.....

I have a Cessna wing for a 180, it weight in at 105lbs with paint read to go... so not that much of a difference. The build it spar is not necessarily heavier, Cessna might have design the wings in a way to leverage production (guessing here) and they might been able to interchange with different types and optimized for the heavier airplanes, thus a little heavier for the lowest on the scale. Bad? To you and I might sound bad, but if you have a single spar production line, it makes great business sense...optimization is a function of the variable you are trying to optimize.... $$$$

As for the RV.... you’ve lost me there, it’s important to understand that struted wing and counter lever wings have two different design concepts, and if you don’t have a substantially stronger attrach point vs a strutted wing, you will be... well let’s say VanGrunsven would not have been so successful.

Interesting enough, adding a truss at the strut attach point of the Piper or Maule wings and been able to move back your main strut, you could balance the forces to have a single strut, provided the strut was a to handle all the loads in the flight envelop. So adding 5-10lbs to you airplane could get you another ~10mph.

Not a fan of metalizing a fabric airplane and a lot of them were very poorly done but I did see a metalized PA-12 once up at O22 that was pretty stunning. I think only the fuselage was metal and I believe this is a picture of it. There was a magazine article titled “The Chrome Cub” that told the story and as I remember there is more than one of these conversions. I believe this is a picture of it.