Trailing Edge Technologies was established to fill a void in the small homebuilt aircraft arena, specifically KR2S wing attach fittings and airfoil drawings.

Jan, 2003 update (added FREE airfoil template download in pdf format)

Unfortunately, we've decided to cease operation. Nothing personal, but we're both concerned about the issue of liability. Although we've done what we can to keep from being sued, the stark reality is that given the US "legal" system, we could still be sued and forced to defend ourselves in court, regardless of the validity or the outcome of the claim.

An example of this would be the ongoing case of the Corvair knockoff fuel pump affair. The story I heard was that even though GM quit manufacturing Corvair fuel pumps in the mid 60's, an aftermarket company reverse engineered it and started making their own version, and probably still make it today. A few years ago a Polish aircraft engine manufacturer discovered the Corvair pump as a good fit for its engine, and incorporated it into its design. A subsequent engine failure in a Swift that had been retrofitted with the Polish engine was blamed on a defective valve in the AFTERMARKET pump, yet GM was quickly sued because it had designed the valve in the beginning, even though it had nothing to do with the manufacture of that particular pump, nor did it ever approve such a pump for use in an aircraft. GM is gearing up to go to court in this matter, despite the ridiculous nature of the suit.

Another good one would be John Denver's estate suing the manufacturer of the fuel valve that was set to an empty wing tank, that John was never even able to reach! And it's not like his estate has a cashflow problem, I'd bet!

My father has been sued for a million dollars on two different occasions, both of which were ludicrous, but it still cost him $140,000 to defend against them, not to mention over a year of sleepless nights. Were we to change our laws so that those who filed these frivolous lawsuits would have to pay BOTH sets of lawyers if they lost, we wouldn't have this problem, but since our legislators are mostly lawyers, that'll never happen.

And although most experimental aircraft builders would scoff at the idea of suing anybody that's been as helpful as we have been to the KR construction effort, their spouses and children may not share that view, and that is where the problem lies. We've enjoyed working with you, but it's just not worth the risk. We've enjoyed working with you, and thanks a lot...

Our goal with this company was not to start an aircraft company and get filthy rich. Obviously, we both had decent jobs that are paying the bills. What we wanted to do was provide high quality, inexpensive aircraft parts and plans to builders who can't afford to spend the time and resources to design and construct them themselves. By subcontracting directly with manufacturing facilities and ordering in large quantities, we used cooperative buying to leverage excellent values in hardware.

One of our products was airfoil templates for the AS5045, AS5046, and AS5048 "new wing" sections, as well as for horizontal and vertical stabilizers. These were plotted out full size on paper (to be glued directly to ribs) and included enough templates for one airplane. These templates used the standard planform, and either stock or modified spars. They were high quality, derived from bspline curves, rather than a french curve, and left very little to the imagination. They were not blueline or Xerox copies, but were direct from a very accurate plotter.

The following information is provided only as an aid to positioning templates of your own creation (perhaps from the coordinates provided by the UUIAC) onto the KR spars. No claim for recommendation of suitablitiy for any application is implied. Use this information only if you have determined through your own research that you believe this airfoil to be suitable for your purposes, and at your own risk.

The AS5046 profile is a best fit for stock KR2S spars. If your spars are already built, you might want to use the AS5046 airfoil. It uses a stock aft spar and a slightly taller main spar, which could be heightened by laminating an extra .125" thick strip of Spruce to the spar cap. The aft spar would also need to be moved up about an inch with relation to the fuselage due to differences in the RAF48 wing shape and the lower incidence that is optimal for the wing. Each airplane varies, and incidence will be perfect using the level lines on the templates. Several people have cut their aft spars out and raised them, and I'm told it's about a 3 hour job.

The AS5048/15 is 18% at the root and 15% at the tip. This would allow a taller spar (but the same materials as shipped in Spruce kit) and would leave more room for wing tanks and aileron bellcrank. Dimensions for the spars for this setup would be something like 8.19 inches tall for the main spar (caps still 2" thick) at the root, tapering to 5.07" tall at the tip. The aft spar would be 4.77" tall at the root tapering to 2.76 inches tall at the tip, again using stock cap dimensions but with longer vertical spacers. Perform your own analysis to ensure that spars of these dimensions are suitable for your use, but generally speaking, taller spars with identical spar caps will be stronger than the original.

The template sets also included REAL airfoil templates for horizontal stabilizer/elevator and vertical stabilizer/rudder. This version of the horizontal stabilizer required a taller spar due to the thicker chord. They are NACA symetrical series airfoils of the appropriate thickness to match the stock KR (in the case of the vertical) and were thickened to 9% for the horizontal to make them more effective and to strengthen the spars.

Coordinates for all of these airfoils are located at http://www.n56ml.com/as504x.html if you'd like to plot and print them yourself. Keep in mind that these coordinates are public domain and are provided merely as a convenience, IF you have determined through your own analysis that they are suitable for your use.

If you are interested in these airfoils, please read all of the information at http://www.n56ml.com/airfoil.html, including the links that discuss the design criteria and performance curves, to make sure that this is something YOU want to do.

There are were different versions of the templates available for FREE download, for use at your own risk. These airfoil template drawings are public domain, and may be emailed to a printing establishment for printing purposes, or merely point them to this web page. All templates below include the tail templates mentioned above. If you don't understand these templates, just back away from the table and say to yourself "this is not for me". If you have ANY questions whatsoever regarding how to implement them, you need to forget about them and go back to the plans. These are intended as a convenience for those who have done their own research and have decided that they want these airfoils for their intended application.
USE AT YOUR OWN RISK, and do not assume that any engineering, testing, or other groundwork has been done for you.

AS508/15 pdf file
AS5046-00 pdf file
for those whose horizontal stabilizers were already fixed at zero degrees of incidence (like the plans call for)
AS5046-75 pdf file
for those whose tails have not yet been glued in place (probably the most optimal of the two AS5046's, due to improved main wing/tail decalage).

You will need to find a print shop with a roll feed printer/plotter that uses 36" wide paper. These plots are 97 inches long. I have no idea how much they'll charge you. The files are 600 dpi, which is plenty. There are two lines defining each airfoil. The inner line is provided in case you accidently sand the outer one off. It leaves you with some clue as to what the original airfoil was supposed to look like.

Instructions for templates are located at http://www.n56ml.com/tet/as5046inst.html and the history of this new KR2S airfoil is located at http://www.n56ml.com/airfoil.html