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Oratex STC Press Release

sj

Staff member
Northwest Arkansas
Lanitz Aviation from Leipzig, Germany is the only manufacturer of the worldwide patented ORATEX6000® aircraft fabric which comes coated & colored and can be flown right after the installation without any painting. It is airworthy right off the delivery roll. There is no other product like it; all other Aircraft Fabric products are naked woven cloth relying on multiple layers of paint that are sprayed by the installer.


Some years ago, the company looked into the designs of aircraft types and had an innovative idea: Why should the covering be attached to an aircraft by the antique time-consuming rib stitching or pop-riveting technology? There should be a better way!


Lanitz Aviation developed a new technology: they implemented cap strips to strengthen the ribs and to substitute bracing tape for the ribs, rib stitching and/or riveting. This process is called the Lanitz Aviation Design-change STC. This STC implements the aircraft fabric by special bonding process only, which means rib stitching and riveting become obsolete.


The very first aircraft STC’ed for this are European Jodel Robin, a very popular 180Hp+ 4-seater in Europe, flown in almost every flying club there. Due to the high performance of these aircraft, they are often glider tugs.


The technology behind the Design-change STC is the installation of special 1.2 mm beech plywood cap strips, consisting of three beech layers, which also enlarge the gluing area of the fabric on a rib. By implementing this technology, the original type design rib stitching becomes obsolete. The


result is a cleaner airfoil with better airflow. Together with the micro-vortex effect produced by the Lanitz Aviation ORATEX6000® aircraft fabric, you succeed in getting the ultimate performance from your aircraft concerning lower stall speed, higher cruise speed and climb rate. This technology has been approved by EASA and LBA (German authorities) as well as by FAA STC.


The second aircraft type Lanitz Aviation implemented this technology in was the Piper PA-18A-180. On December 1st 2023 the FAA approved the Lanitz Aviation’s Design-change for all N-registered high-wing Pipers according to the AML of the STC.


At EAA AirVenture Oshkosh 2024, Lanitz Aviation will demonstrate the covering process in real time at their sole distributor’s booth, Better Aircraft Fabric (booth #300). Before that date, Lanitz Aviation will be publicly covering the very first STC’ed US Piper PA-18 in Ohio (on display in Oshkosh). Due to limited space in Ohio, interested customers are kindly requested to contact us at www.Oratex6000.com


Lanitz Aviation is also inviting maintenance companies interested in learning the application process of ORATEX6000® and the installation of the STC. Take note, the STC will only be available to qualified builders.


As Lanitz Aviation extends the STC AML, the unstitched Design-change already got implemented in the following homebuilt aircraft: Pitts special S1-S, Stolp Starduster, Carbon Cub, Just Aircraft Highlander & SuperSTOL, Rans S9, Savage and Savage Cruiser.


At the moment, Lanitz Aviation is in STC approval for Christen/Aviat Husky unriveted and Maule MX4 and MX7 unstitched. The goal of Lanitz Aviation is to offer future Design-change STCs for the majority of the existing rib stitched and riveted aircraft fleet. The implementation of this process and ORATEX6000® aircraft fabric will save installation time and money, increase the aerodynamic performance and reduce the empty weight.


For those interested in learning more about Lanitz Aviation’s Design-change and ORATEX6000® aircraft fabric, as well as their workshops and tradeshows, we invite you to visit the homepage at www.lanitz-aviation.com. – Or contact the exclusive USA-Canada Dealer at: www.Oratex6000.com
 
I am curious about this cap strip and how it installs and eliminates rib stitching. I emailed Lars after I searched their website and couldn't find anything.
 
Don't some ribs like lite Piper truss types need the rib stitching to keep the rib from pulling apart?

Glenn
 
There is a surprising amount of force on the top of the wings that we don’t get to see.
762bae34aa30823dcf42b6a35ca3e00f.jpg

2dabdab1119ba4a2f6dc92e234e39016.jpg



Sent from my iPhone using Tapatalk
 
There is a surprising amount of force on the top of the wings that we don’t get to see.
762bae34aa30823dcf42b6a35ca3e00f.jpg

This picture says more than the amount of lift on the wings. Look at the aileron. The fabric is doing just the opposite of the wing fabric. That is telling me, there is some drag there. Here's a question: What would happen if the shape and thickness of the aileron was increased? Would there be less drag? Would there be improved roll response? I know this is the only existing flying Stinson A, but the questions also apply to the Cub wing. Has anyone messed with increasing the thickness and camber of the Cub's aileron?
 
The Cub Crafters FX2, FX3, X Cub and NX Cub have symmetrical airfoil ailerons and they are so much lighter in feel, more effective and quicker than the standard Cub aileron. I would love to change the ailerons and false spar to accommodate they same shape on my Super Cub. Maybe even shorten the ailerons and lengthen the flaps.
 
There is a surprising amount of force on the top of the wings that we don’t get to see.
762bae34aa30823dcf42b6a35ca3e00f.jpg

2dabdab1119ba4a2f6dc92e234e39016.jpg



Sent from my iPhone using Tapatalk

I bet $1 that is heavy fabric done in the blanket method. Learned about this the hard way on my Pitts wing. Heavy fabric shrinks way more in twill than weave (or weave than twill -can't remember) so if you use it on any aircraft and roll it out over the span of the wing you will get this issue. I seem to remember 30% difference between the two.
 
This picture says more than the amount of lift on the wings. Look at the aileron. The fabric is doing just the opposite of the wing fabric. That is telling me, there is some drag there. Here's a question: What would happen if the shape and thickness of the aileron was increased? Would there be less drag? Would there be improved roll response? I know this is the only existing flying Stinson A, but the questions also apply to the Cub wing. Has anyone messed with increasing the thickness and camber of the Cub's aileron?

Aviat has with the new wing Husky (2006 and newer). I don’t know about drag reduction if any but the roll control is greatly improved, less stick force, better roll rate.

Kurt
 
Pete, to expound on Steve’s response, the CC ailerons are thickened so they extend up into the boundary layer, just as you are asking about.
The trailing edge is also sq cut thicker rather than tapered to a point.


Sent from my iPhone using SuperCub.Org
 
There is a surprising amount of force on the top of the wings that we don’t get to see.
762bae34aa30823dcf42b6a35ca3e00f.jpg

2dabdab1119ba4a2f6dc92e234e39016.jpg



Sent from my iPhone using Tapatalk

A wing that is loaded (positive g in-flight) puts a bending moment on the wing spars resulting in the top of the spar being in compression and the bottom of the spar in tension. Guess what this does to the "skin" (top photo). Conversely, the opposite occurs when the wing is unloaded (bottom photo). Looseness in the skin (any skin type) only exacerbates the ripples/oil canning under given loading whether positive or negative. There is also some discussion reference rib lacing contributing to rib strength. It is highly unlikely the strength of rib lacing cord is considered in the stress analysis of an engineered truss style rib, furthermore, the lacing cord is at a 90-degree angle resulting in nearly zero torsional resistance. The angles of the inter-rib bracing comprising its truss structure are designed to oppose the torsional loading caused by the center of pressure acting on the wing as well as loads in compression and tension due to bending moments. One could argue that due to the lacing physically attaching both the top and bottom chord of the rib, it adds strength. In its purest form, this is true, however, if you subscribe to that logic, I assume all the trusses in your home and hangar have rope from the top chord to the bottom chord.:lol:
Now, for the real topic of this thread, I talked with Lars last night. The press release is indeed true. However, due to the difficulties they have had with former legacy system users not following their instructions in the application of Oratex, one must attend their training to be qualified to install their fabric using this newly approved procedure. I volunteered my O-360 powered PA-18A as I am in the process of removing my present covering and intend to use the Oratex process . Unfortunately, they already have a Cub lined up out in Ohio. FWIW, my Ceconite, with Randolph process, top coated with Forrest Green Butyrate was installed in May 1972! Rejuvenated twice with J3000. Working floatplane so this fabric has had a hard life. Pulled to 85 pounds per 43-13, as that is all I could fit in my bucket with no break or degradation, tough fabric indeed. Just a data point ref fabric age and strength, that's all, no need to tell us all that you have the Flintstones biplane still flying with the original pterodactyl skin! We'll see if Oratex does as well in the long haul. TR
 
From Lars at Better Aircraft Fabric in Alaska:

Hi Steve,Thanks for the email and thanks for posting the press release on ShortWingPipers! - Yeah the cap strips are glued onto the original ribs with a special two component glue that is able to really bond with aluminium. Of course with this method as a hole the workmanship is extremely critical and following the manual in every little detail is a must. When everything relies on a glue bond there is no redundancy like mechanical fasteners like rib-stitch or rivets. The ribs get strengthened a whole lot with this method and the glue surface gets bigger etc.
With the solvent free glue clean working conditions will be again of paramount importance, contamination of glue surfaces with stuff like Butterfingers, Burger Grease, Pizza Oil, sunscreen or Handcream would be a real mess.
If you want to talk with somebody who owns a plane built that way years ago, I can put you in contact with Rick Papp in Ohio.
Best Regards from Alaska,
Lars

A lot of us know Rick Papp I will reach out to him and see if he noticed anything different about how his Carbon Cub flies before and after.
 
A wing that is loaded (positive g in-flight) puts a bending moment on the wing spars resulting in the top of the spar being in compression and the bottom of the spar in tension. Guess what this does to the "skin" (top photo). Conversely, the opposite occurs when the wing is unloaded (bottom photo). Looseness in the skin (any skin type) only exacerbates the ripples/oil canning under given loading whether positive or negative. There is also some discussion reference rib lacing contributing to rib strength. It is highly unlikely the strength of rib lacing cord is considered in the stress analysis of an engineered truss style rib, furthermore, the lacing cord is at a 90-degree angle resulting in nearly zero torsional resistance. The angles of the inter-rib bracing comprising its truss structure are designed to oppose the torsional loading caused by the center of pressure acting on the wing as well as loads in compression and tension due to bending moments. One could argue that due to the lacing physically attaching both the top and bottom chord of the rib, it adds strength. In its purest form, this is true, however, if you subscribe to that logic, I assume all the trusses in your home and hangar have rope from the top chord to the bottom chord.:lol:
Now, for the real topic of this thread, I talked with Lars last night. The press release is indeed true. However, due to the difficulties they have had with former legacy system users not following their instructions in the application of Oratex, one must attend their training to be qualified to install their fabric using this newly approved procedure. I volunteered my O-360 powered PA-18A as I am in the process of removing my present covering and intend to use the Oratex process . Unfortunately, they already have a Cub lined up out in Ohio. FWIW, my Ceconite, with Randolph process, top coated with Forrest Green Butyrate was installed in May 1972! Rejuvenated twice with J3000. Working floatplane so this fabric has had a hard life. Pulled to 85 pounds per 43-13, as that is all I could fit in my bucket with no break or degradation, tough fabric indeed. Just a data point ref fabric age and strength, that's all, no need to tell us all that you have the Flintstones biplane still flying with the original pterodactyl skin! We'll see if Oratex does as well in the long haul. TR

On a stamped alum or plywood routed rib the rib stitching is there to hold the fabric from sagging on the bottom and ballooning on top. The early wooden stick constructed truss type ribs are fragile. Planes like a Tiger Moth or Aeronca L3 are examples. Pipers riveted light weight truss is not a whole lot stronger, you could easily deform one by pulling with your hands.
That's why other aircraft builders switched to stamped ribs and rivits or screws. More weight but less labor.

Glenn
 
If you need a clean and level surface to attach the cap strips how much work is going to be needed to get a good bond on used/spliced ribs? Can the cap strip be removed if you want to go back to a legacy system? Do the cap strips also go on the bottom? Do you still need to do a tape strip over all the ribs if you are not doing rib-stitching. It certainly would make for a quick wing cover if no extra tapes are needed and no worry about glue turning brown down the road. It it works it should give a boost to the product.
DENNY
 
Sounds like to me I can rib stitch in less time it takes to glue all of these cap strips on.

I thought the whole idea of rib stitching a truss rib was so the whole rib carried the load of the fabric trying to balloon rather than the cap strip. I guess gluing the wood cap strip on strengthens the rib considerably.
 
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On a stamped alum or plywood routed rib the rib stitching is there to hold the fabric from sagging on the bottom and ballooning on top. The early wooden stick constructed truss type ribs are fragile. Planes like a Tiger Moth or Aeronca L3 are examples. Pipers riveted light weight truss is not a whole lot stronger, you could easily deform one by pulling with your hands.
That's why other aircraft builders switched to stamped ribs and rivits or screws. More weight but less labor.

Glenn

My objective for my previous post was only to clarify perceived misconceptions regarding "Piper truss types" as you reference in post #5. Note, I make no reference to stamped or plywood routed ribs as you now newly address. Nor was the problem of so called "ballooning" previously addressed as this is an attachment issue, not a structural issue, as the aerodynamic forces imposed by the airflow are already considered in the design of the truss style rib. Regarding your comment reference the fragility of the truss rib structure, it is not designed to be "pulling with your hands" as you state, it is designed to carry a distributed calculated load. Wings employing truss style ribs can carry thousands of pounds of distributed loading, however, not capable of a very low point load without structural degradation, (as pulling or pushing on them individually). For this reason, we re-enforce the area we need to walk on to board a biplane for example. Are the ribs covered in a weight distributing material that is capable of supporting point loads stronger than the outboard fabric only covered ribs? Absolutely. However, not many would desire the weight penalty of covering all ribs in this fashion nor is it required for structural integrity as long as the lack of rigidity of the wing skin, (fabric in this discussion), is considered in the rib design. TR
 
My objective for my previous post was only to clarify perceived misconceptions regarding "Piper truss types" as you reference in post #5. Note, I make no reference to stamped or plywood routed ribs as you now newly address. Nor was the problem of so called "ballooning" previously addressed as this is an attachment issue, not a structural issue, as the aerodynamic forces imposed by the airflow are already considered in the design of the truss style rib. Regarding your comment reference the fragility of the truss rib structure, it is not designed to be "pulling with your hands" as you state, it is designed to carry a distributed calculated load. Wings employing truss style ribs can carry thousands of pounds of distributed loading, however, not capable of a very low point load without structural degradation, (as pulling or pushing on them individually). For this reason, we re-enforce the area we need to walk on to board a biplane for example. Are the ribs covered in a weight distributing material that is capable of supporting point loads stronger than the outboard fabric only covered ribs? Absolutely. However, not many would desire the weight penalty of covering all ribs in this fashion nor is it required for structural integrity as long as the lack of rigidity of the wing skin, (fabric in this discussion), is considered in the rib design. TR

So...your saying the design or material a rib is built from makes no difference on the way the stress is distributed?

Just trying to learn. Been involved with early aircraft 1907 - WWII with very lite wing construction

Glenn
 
So...your saying the design or material a rib is built from makes no difference on the way the stress is distributed?

Just trying to learn. Been involved with early aircraft 1907 - WWII with very lite wing construction

Glenn
I have no idea how you can construe such a statement/question from my post/s. I never stated nor implied as you reference here (at least that was not my intention). We were merely discussing the merits of lacing in regard to rib strength in the truss style rib design (your post #5) and for reasons unknown, you followed up by discussing a different engineering design and to add more confusion stated your perceived reasoning for the lacing in those type designs. I do not recall rib structure material even being discussed, only truss type design. I choose my words with thought with the objective of clarity, sometimes I falter in that endeavor and if so I do apologize. My purpose of participation on this platform is education supported by proven science, it appears I have failed in communicating this case with you, perhaps other readers deciphered my words differently than you have meeting my stated objective. Over and out. TR
 
I have no idea how you can construe such a statement/question from my post/s. I never stated nor implied as you reference here (at least that was not my intention). We were merely discussing the merits of lacing in regard to rib strength in the truss style rib design (your post #5) and for reasons unknown, you followed up by discussing a different engineering design and to add more confusion stated your perceived reasoning for the lacing in those type designs. I do not recall rib structure material even being discussed, only truss type design. I choose my words with thought with the objective of clarity, sometimes I falter in that endeavor and if so I do apologize. My purpose of participation on this platform is education supported by proven science, it appears I have failed in communicating this case with you, perhaps other readers deciphered my words differently than you have meeting my stated objective. Over and out. TR

Thank you, just trying to learn

Glenn
 
Sounds like to me I can rib stitch in less time it takes to glue all of these cap strips on.

I thought the whole idea of rib stitching a truss rib was so the whole rib carried the load of the fabric trying to balloon rather than the cap strip. I guess gluing the wood cap strip on strengthens the rib considerably.
Rib stitching transfers the lifting loads of the upper layer of fabric to the bottom of the rib so that the loads are pushing up against the entire rib truss.
Gluing the fabric to the top of the rib generates a pulling load on the upper rib cap strip only. Thus the lifting loads will tend to pull the rib apart. Is this good, bad or doesn't matter???

With the traditional methods of attachment whether it be dope, Stewarts, Polyfiber etc there is always an adhesive of some variety brushed through the weave onto the rib caps. The fabric is not just loose with concentrated loads at the fastener location.

This new procedure eliminates the up load on the bottom therefore the entire rib.

I'm not privy to the original engineer's load path thoughts.

Some procedures involve screws, rivets or martin clips into the upper cap strip, thereby a pulling load.

This new process appears to be eliminating rib stitching on ribs which had been designed to have the stitching. In order to become comfortable with this new procedure I would like to know what engineering decisions were made which addressed changing from pushing to pulling loads?
 
Sounds like to me I can rib stitch in less time it takes to glue all of these cap strips on.

What about repairs? It seems that if the glue is strong enough to eliminate other attachments, peeling the fabric off will likely damage the cap strip enough to require replacement. That doesn't sound like much fun.
 
I think Steve Wittman was still rib stitching. As I recall the problem was continued use of brittle ol' Nitrate Dope instead of Poly Tac when wrapping and lapping Stits at the LE.
 
I think Steve Wittman was still rib stitching. As I recall the problem was continued use of brittle ol' Nitrate Dope instead of Poly Tac when wrapping and lapping Stits at the LE.

I think they figured out that he glued the cecenite to the ply sheeted wing from the top only. Never put a coat on the plywood first which would have encapsulated the Dacron fabric. He was used to cotton that was porous

Glenn
 
I’m sorry, but no way am I trusting just glue to keep my fabric attached to the ribs. I get the theory, but I’ve seen way too many glues fail or let go for a whole variety of reasons- poor surface prep, effect from other chemicals/fuel, or just plain age. Honestly I fail to see how it can be any less labor than rib stitching, and I missed it if there are other benefits.
 
I’m sorry, but no way am I trusting just glue to keep my fabric attached to the ribs. I get the theory, but I’ve seen way too many glues fail or let go for a whole variety of reasons- poor surface prep, effect from other chemicals/fuel, or just plain age. Honestly I fail to see how it can be any less labor than rib stitching, and I missed it if there are other benefits.

Is this STC is to save time? I don’t get it. Maybe it’s an appearance thing? Rib stitching is not that big a deal. I cant figure how attaching plywood strips to each rib would take less time than rib stitching.Only benefit I can think of would be no cords for the mice to chew on? Maybe I’m missing something here.
Marty57
 
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