Pilot Reports



Piper PA-28-160 (Hoerner style wing tips and wing root fairings)


As promised I'm sending you pics from my plane with the wing tips and wing root fairings installed.

The parts improved flight characteristics, landing and overall performance incredibly - I'm very happy and quite impressed!

In flight, it is much more stable now. Landing is smooth, easy and stable. And rate of climb has improved noticeable.

This really was a good investment!


Thanks again for everything you did for me and kind regards from Hamburg,




Some Comments on Speed Kits



Hello Kevin,


Through Hill Aircraft in Prince George, I have recently purchased the following performance mods for my 1974 PA28-151 Piper Cherokee Warrior:

-       Upswept wing tips (with landing lights).

-       Wing root fairings.

-       Flap and stabilator gap seals.

-       Flap/fuselage gap seals.

I tested out my Warrior before and after the installation of the performance mods and here are the results:

-       Noticeable shortened takeoff run (have not got the distance measured yet).

-       Normal rotation speed is 65 mph, now the plane wants to rotate at 55 mph.

-       Greatly improved climb rate (averaging about 300 ft per min. improvement)!!

-       Faster cruise speed at 2300 rpm of about 5 – 6 mph.

-       Reduced stall speed – get this – from 58 mph down to just under 40 mph!!

-       Improved stability at slow speeds for example, on approach descent to the runway, the normal approach speed is 80 mph, I can slow the approach speed to 70 mph and the plane feels really stable.

-       Noticeable shortened landing run (have not got the distance measured yet).

I just want to say that I am really happy with the improved performance and safety since the above noted mods were installed on my Warrior.


Best Regards,

Lyle Larsen




..................With these speed mods, the Arrow handles noticeably better, has a lower stall, and has five to ten MPH faster Cruise. The mods were from Knots 2U. The installation instructions were clear and easy to follow. Also Knots 2U gives you a discount if you buy all of the mods at the same time as a package.

The only problem we had was a few small puckers on the stabilator gap seals but probably due to me not using as many clecos as specified in the installation directions while doing the final riveting. In summary, the mods are well worth the money and approximately 40 hours of installation time.

Gary Kundey Midland GA Mods Installed: Gap Seals, wheel well fairings, flap hinge fairings, and Met-Co-Aire wing tips.

PA-28R-180 Re-printed from March 2003 Piper Owners' Magazine


Att Mr John Bailey


Dear John

I purchased the wing root fairing kit, the complete control surface gap seal kit, and the flap hinge fairing kit for my PA 28-235. I had the hardware fitted by my local amo and found that the total speed increased at 21 inches of manifold pressure, motor slightly rich of peak of lean, at 8500 feet above sea level by 7 knots from 128 to 135. Rate of climb from 5500 feet to 8500 feet increased by 130 feet per minute. The big difference is in my landings. I have always found the sink rate to be high and elevator to be rather heavy especially during the hold off. Elevator effort has decreased noticably, and aileron response is far better than standard, which has improved my landings considerably. My plane is fitted with locally produced spats, but I am removing them to fit your main gear fairing kit. Please confirm whether you still have my credit card details and delivery address, and despatch a set asap




Writing you to comment on the significant performance increase of my C172N (160HP O320-H2AD) with the Knots2U lower cowl fairing and nose gear wheel fairing (using standard Cessna late model main wheel fairings). Pre installation speed at 2,525 rpm was 120-121kts true a.s. at 4,500 and 5,500msl, and 115-116kts true a.s. at 8,500msl. Post installation speed is now 125-126kts true a.s. at 4,500 and 5,500msl, and 120-121kts true a.s. at 8,500msl. This is an increase of 5kts/6mph. Pre installation speed of this aircraft was with Powerflow exhaust, flap and aileron gap seals, and brake fairings. Post installation speed included the lower cowl fairing and nose gear fairing.

The aircraft had a high time engine during the speed tests; it is now being overhauled, so performance will increase after break in. Aircraft rigging at test time was not totally perfect, with a very slight left banking tendency. Air was smooth at all times.

It's amazing what a simple thing an air filter can do. I just installed the K&N filter in my Piper Cherokee 140 per service manual and your STC and found the following:

To preface I have been a test pilot, and have been flying the 140 for many hours.  I say this so that you all know that when I say I am at Vy I really am at Vy and not +/- a mile or two.

I started with the tanks at the tabs, and flew two trips, the first with the stock filter, and the second with the K&N.  I refilled the tanks to the tabs for the second flight so the weight would be identical.  I fly out of PAE with a field elevation of 603, so I went east to the Snohomish valley to start the test.

At 500 MSL I entered a climb, full rich & full power and Vy which in the 140 is 85 mph IAS. Passing through 1,000 I started the timer. I noted the time and VSI at 2500 MSL and 5000 MSL. Passing 4000 MSL I leaned to best power based on EGT.

  Before After
Max Static RPM 2410 2430
Time to climb    
2500 1:56 1:48
5000 5:45 5:26
2500 800 fpm 800 fpm
5000 650 fpm 700 fpm
TAS 2650 RPM 5000 MSL PA 130 mph 132mph


For the maximum static rpm I did the run up at the end of the flight so I was sure the engine was at operating temperature.   For the TAS I dialed in Pressure Altitude and flew at 5000 MSL at 2650 RPM (digital tach) and re-leaned to best power.


This is far from a scientific test, but with the digital instruments  and the tests within 15 minutes of each other I think the results are fairly accurate. 




These mods now give performance similar to that of a 180hp engine change, but provides the same hourly fuel burn of the 160hp engine, but with higher speeds than the standard 160hp engine. Note that the miles per gallon, however, are now considerably better than the 180hp or 160hp engines in unmodified C172 aircraft. With 58 gallons of useable fuel my range is now about 900 to 906 nautical miles (7.25hours/8.0gph), with no reserve.

I am now thinking about of adding your VGs, but would like to see an actual test(s) of a C172, pre and post installation of VGs, to verify actual performance changes on the same aircraft. Do you have any such test results?

Thanks for the mods and for any information you can provide.

Regards, Adi Pohan

Greetings Folks:
I just completed the installation of the Gap Seal Kit for my PA28-140 and I wanted to give you some feedback.  First, my plane is already modified:

Standard O-320 (about 600 hours)
Powerflow Exhaust System
AMR&D Prop Mod
AMR&D Stabilator Tips
Met-co Wing Tips
Prop pitched to max cruise
Knots 2U wheel pants
Laminar flow nose pant

With this setup, I was getting the following numbers (approx.):

Gross Weight:  2050
80 degree day from our field, 1437MSL, winds calm
Climb out at 85mphIAS, 950ft/min
2250 RPM to maintain 100mph IAS in the pattern
@4000ft, 2800 Redline, 139mph IAS

These are all pretty good numbers, the extra power is nice as our field is only 2000ft.  Last night I did some testing flying after installing  the Gap Seal kit:

Conditions were very close to those above
Climb out at 85mph IAS, 1050ft/min
2150 RPM to maintain 100mph IAS in the pattern
@4000ft, 2800 Redline, 143mph IAS

These are my initial readings after only two hours of test flying.  This says nothing about the flyability of the airplane, which has really changed.  The responsiveness of roll and pitch is much improved, the plane feels more stable making standard turns in the pattern at pattern speeds.  It also seems that there is more authority with both pitch and roll at slow speeds, especially at stall speeds.  I'm sure my stall speeds are 4-5mph lower than a stock 140, the plane is just very stable at slow speeds now.  In addition, the controls work smoother, meaning that I can smoother on the controls without having undo what I just did
in small adjustments.  I guess it seems that it is easier to be more precise on my flying.

A word or two about the kit.  I've installed your wheels pants before and found the Gap seal kit to be just as easy to understand and the materials provided are of top quality, fit and finish.  Keep up the good work and thanks.

Free Union, VA

I also planned, over time, to add the most cost-effective speed modifications from Knots 2U until all were included. Initially the wing root fairing, stabilator gap seals, aileron gap seals and flap seals with flap hinge fairings were installed. later the gear lobe fairing and slimline strobe were added.  These changes have, as best I can measure, increased the speed a consistent 12-14 knots. The low speed handling characteristics are now more responsive and have made landings more precise.  It is truly a fun plane to fly airplane that can hold 149-150 knots in calm wind at 3,000 feet.  


Arrow II      August 2002 Piper Owners Magazine


Hi Guys:  I installed a flap gap kit on my 172N at the last annual.  I ordered the painted kit and the resulting installation is very neat, fits well.  Many of my tie-down neighbors have commented how the gap seals look "factory" installed. 


Performance enhancements are as your testimonials say.  I fly from an 1800' strip with tall trees at one end, and lower controllable approach speed matters.  Stall speed is noticeably reduced, by about five knots indicated, with full flaps.  Flight at lower indicated airspeeds on final feels more secure with the flap gap seals.  Cruise speed is up 2-3 knots and rate of climb is up 50-100 FPM.  These estimates are flying in muggy 80-90 degree Fahrenheit temperatures in July and August.  Can't wait to see what she'll do on a standard day!  Needless to say, your product installs and performs as advertised.  A bargain price performance gain with no downside whatsoever.  Thank you! 


Chuck V.
Baltimore, MD


FYI:  Just installed the new K2U flap gap seals onto my 1978 Cessna 182RG, and am very pleased with the enhanced performance and professional look of your product.  Without giving exact numbers, the take-off run is noticeably shorter, climb is quicker, and the airspeed indicator sits slightly in the yellow when cruising between 7500 to 8500 feet.  I've had to adjust my landing technique to slightly slower approach speeds and less power - but power-off landings feel much more controlled than before the seals.

 From a happy Skylane RG guy who now confuses the controllers into thinking I am a Centurion 210, thanks for a great product that does what you said it would.

Medford, Oregon

Howdy John,

Cessna 172G, 1966 with a 220 HP Franklin and a constant speed prop. Columbia Marine STC.

I installed the knots2you gap seals and have some preliminary figures and will send more as I get the whole deal. I live near Seattle so we don't fly as much as we'd like up here. I am taking a trip to L.A. and will be able to give some real numbers from that trip.

What I have noticed is a real upgrade in take off performance with 10 degrees of flaps. I didn't figure on this as my original goal was speed. I didn't keep any records on take off or landing performance so I don't know what the exact numbers are but I can tell that there is a substantial difference now compared to what I used to feel.

Take off is shorter...  much shorter. I am on a really small field and it has lots of gravel so I always like to get off as soon as I can as I worry about my prop all the time on the ground. I don't have any solid numbers but if I can tell there is such a big difference the numbers must be quite different for take off.

Landing is quite different. When first entering down wind I usually carry 16 inches manifold and 100 MPH and a sink rate of about 200 feet per minute. I tried this with the seals and was doing 100 MPH but no sink. None. When I got to base I was too high. It really feels slippery and smooth.  To get the sink I need I have to go to 14 inches and 90 MPH to get the 200 feet per minute. 10 degrees of flaps  and slower speed feels really smooth with no buffeting. 20 degrees is where I would feel some flap turbulence before, but not now. It feels really smooth and no buffeting and turbulence all the way down to the ground. Flare is now flatter and I pull just a little later than I used to to get an easily controlled even flare.    Remember, this is a Cessna 172....

For speed test I did a two way run at 6500 Feet. First was flat out full throttle and 2650 RPM. I averaged on the GPS 157 MPH for the two way run. About 5 minutes each way.  Next was a lower RPM of 2450 and still at full throttle. About 5 minutes each way yielded 151 MPH..  I usually fly at 8500 feet so when I run to L.A. I'll have the numbers at that altitude in about a month. I used to get 151 MPH at full throttle and 2500 RPM at 8500 Feet.

Franklins don't do well at low RPM so I pull the prop back until the vibration gets smooth and run it there.

Sam Dodge CPA#30878


 I purchased quite a few mods from you folks about 2 months ago.  I ordered the wheel mods, gap seal kit, wing root fairings and flap/fuselage seals for N8502W (the world's oldest Cherokee 235).

 I used to own a Cherokee that had some of your mods, and was pleased with the performance.  The old Cherokee had "Fancy Pants" instead of yours and I wasn't too thrilled with the cracking and such on them.  This time I ordered everything from you except for a nose gear spat (which you don't offer).

I have to say, your products are head and shoulders above Fancy Pants. The construction and installation is far superior, and the pride in workmanship is obvious. I should know about glass workmanship, I am almost done building my own Velocity, and your work is Very nice.

Along with the work:  The parts arrived on time and for much less shipping than Laminar Flow wanted.

All in all.. Great Job !!  I just thought I'd tell you.  Nice to see good work now days.


Good afternoon. I was asked by one of customers to install a fairing kit on his Cherokee 140. He ordered wing to fuse, flap hinge, wheel pants and wing tips. I installed the wing and flap kits today and I must say that I am very impressed with the fit and finish on your product. This is the first time that i have installed mod parts on a general aviation aircraft (all of my work is homebuilt, exp stuff) and was surprised at the quality of your product and will recommend them to any one who wants to listen.


Your install estimate is pretty much on the money. Ill let you know about the wing tip install after I do it.


 thank you
pat mc gilly


I recently had your Knots 2U Flap Gap Seal installed on my Cessna 172 by Cardinal Aircraft at Campbell Airport in Round Lake, IL.  After five hours of flying and comparing before and after performance I can state that the kit does exactly as promised.

The installation of the kit really adds to the appearance of the aircraft. Everyone who has seen it commented how it cleans up the bottom of the Cessna wing.

It's a quality product and well worth the modest cost.


Mundelline, IL

P.S. The slower landing speed and shorter ground roll should prolong tire and brake wear.


I have been in the aviation business for over 15 years and wanted to let you know that I have worked with many dealers in aircraft parts but have never found another company that matches your quality standards.


We are very, very pleased with our recent order, Cessna wing tips with landing lights. The parts were in excellent condition, the instructions were thorough and precise and the installation took less time than quoted.


Again, I have been in the business for a very long time and will not only continue to use your services in my shop but highly recommend you to my constituents.


Steven E. Lissberger
General Manager, Seven Valley Aviation
Cortland, NY


............Awhile back I ordered the MAIN GEAR FAIRING KIT for my Cherokee and it's GREAT.  Not only does it  look great but it also saves me nearly 3 gallons of fuel over a two hour leg. I know this because a friend of mine who owns an unmodified Cherokee and I flew formation from Abilene to San Antonio's Stinson Field.  I burned 14.1 gallons and he burned 17.3 gallons with similar results on our return trip.  I've got him convinced on getting the speed mods but if he will, I don't know.  BTW, my Cherokee is a 160hp and his is a 150hp.     


Thanks for your help.
Chris Ulibarri      Abilene, TX 79606


Greetings Folks:

Just wanted to let you know that I just put the Main Gear Fairings on my Cherokee PA28-140.  I must say, I was skeptical of the claims, but they are right on.  I'm getting about 200ft/min additional climb out @3000/ft MSL and my cruise has increased by at least 5mph indicated @5500/MSL.  Bottom line, it's a great kit, easy to install (I did the work myself, supervised of course!), very affordable and it delivers. 

-Mike Noe, Free Union VA, PA28-140

........when I installed the Wing Fillets they were the only mod made at that time.  I've got to say that your "removing the slam dunk" statement doesn't go far enough.  The wing now hangs on like my Archer (with all of your mods) used to. I could never save too high of flare before but now I just keep pulling the nose up and it just settles to the ground.

Ed Moore          PA-24 Comanche

............We installed a full complement of Gap Seals from Knots 2U.  These included seals for the Stabilator, ailerons, and flaps.  Also installed were the six pieces of special flap hinge fairing.  The results were impressive.  In order of increasing benefits they are:

      1)   There was an increase in overall speed.  the best I can calculate is about 4-5 knots, but this is   the least of the improvements.

     2)    There are some Cherokee pilots who claim that Hershey-Bar  wing Cherokees roll like a fat dog.  Adding the new fairings has changed this markedly.  The feel is much more responsive and controllable than ever before.  


     3)    There is significant control authority improvement during approaches and landings.  The airplane feels much firmer during landings.  Tracking the centerline during final is much more accurate now even in squirrelly cross winds.  Our 29-year old Cherokee is behaving more like an Archer now.


     4)    The most improved aspect of the streamlining has to be the rate of climb.  The airplane now climbs like the proverbial homesick angel!  Even on hot sticky days,  I can typically reach pattern altitude by the end of the runway.  We generally fly with full fuel and two people.  The new and improved climb has become a fun thing to do;  I look forward to it.  As you well know this really says something for the short Cherokee 180 that has always been a nose heavy rascal!


The seals are of very high quality.  I especially like the Stabilator installation.  Jim Bradshaw is to be congratulated for his high quality products and his approach to customer satisfaction...........


Letter to October 1994 Piper Owners Magazine  by Bob Hechlinski.


.......I elected 2,400 rpm and 23.8" manifold pressure to achieve 75% power, and ASI settled at a decisive 190 mph, which trued out at 200 mph (174 Knots). Now that is moving for a Comanche, and according to my information, 13 knots faster than standard ............... 65% power at 4,000 ft......... the engine sounded good at 2400, so I set the recommended 21.4" and the IAS said 178 mph, representing 188 mph true (164 knots), which is 3 mph faster than a standard 260 at 75%......


* November 1988 PILOT Magazine (flying a PA-24-260 Comanche with KNOTS 2U, Wing Root Fairings, Arapaho Windshield, and Gap Seals)

          Flight test by Alan Bramson.

We just wanted to drop you folks a note so you could put us on your "increased speed by 10mph" list.  We have a Piper Cherokee 235 pathfinder and it did about 150 mph at 24/24 and 1500 ft. in 40 Degree F temp.  After the tail fin strobe, flap gap seal, flap/fuselage gap seal, and aileron gap seal we see 155-160 mph at same settings, alt, & temp.  Its a lot "harder" to slow down on downwind leg. 


Ed. M. Levine


.......We had the KNOTS 2U mods done in 2 steps. First the Aileron, Flap and Elevator Seals were done. This resulted in approximately 8 knots increase in speed at 24/24. The second step was the rudder gap seals, Dorsal Fin and Wing Root Fairing.......the 2nd set of mods brought us up to 11 knots above pre-mod cruising speed. FLYING MAGAZINE flew N7269P before and after the first set of gap seals and also confirmed the increase in speed and improved stall characteristics.....


*July 1982 Comanche Flyer Magazine. PA-24-250


I have also installed several of the Knots 2U mods.  They have increased the speed by about five to eight miles per hour. The greatest benefit has been with the handling. The stability of the plane has been improved, especially during the flare on landing.  I have been totally pleased with the Knots 2U mods.
Tom Steel..........Piper Owners Magazine October 2000.........Piper of the Month

The three kits ordered (Wing Root Fairings, Flap Hinge Fairings, and Gap Seals) made a remarkable difference in my plane.......what I noticed right away was a decrease in noise. The plane almost quite vibrating. The artificial horizon used to dance at cruise, but now is steady. Climb was responsive. Landing is simpler, the approach speed can be made at about 60mph over the numbers and the plane doesn’t drop out suddenly and make a hard landing. Speed was increased by 8-10 knots....only problem is that I needed new numbers for approaches, 19" MP no longer gives 90 Kts, now it is about 16 or 17 inches.


*Billy J. Adams, Adams Electric. PA-28-235


Gap Seals for my H35, 1957 Bonanza was an inexpensive mod for the performance.  At lower altitude I'm getting 3-4 knots indicated a/s.  I fly from New Orleans to PSP at 12,000 and 15,500.  I'm getting a 6kts increase at 15,500. Sea level climb I get 200' increase.  Also lands about mph less with good aileron response.


Tom Roman.....ABS Member


We are very well pleased with the KNOTS 2U kits, and with the ease of installation by using the step by step installation guide. Our customer is very pleased with the "better than advertised" performance. They report about 10 kts improvement in cruise speed, 200 fpm gain in climb performance, and better aileron authority at lower than previous stall speeds.


*Tim Fritschle. Corporate Aircraft Refinishing, Inc. SENECA II


.......The KNOTS 2U mods - all of them, including the Flap/Fuse and Stabilator Seals. These give us a wonderful choice of faster or less fuel. We almost always use 75% power. Block to block fuel consumption dropped to just under 11 gph. Speeds increased 5-10 kts (at 19,000 ft we get 182 kts)....... Also climb rates are terrific, no sweat to 1,000 fpm at 100 kts except when fully loaded in high temperatures. In January, coming back from Florida at 17,000 ft, we asked for 19,000 ft. The controller asked if we could get there in less than four minutes......made it in three!


*Nate Newkirk August 1992, Aviation Consumer 1977 Turbo Arrow


.......I wanted to let you know that I am recording a 5-6 knot increase with the installation of your kits. Handling, climb, and landing characteristics have all been improved. And like you said I am hooked. Enclosed is a check for $125.00 for the flap hinge fairings for my PA-32R-301........


*Rick Bryan Bryan Equipment Sales PA-32R-301


........"Air Cherokee" has been clocked at 140 mph while level at 15,500ft by Albuquerque Center. On a really slow night, while on my way to Tucson, the controllers did not believe the data strip- that I was a Cherokee 140- They phoned Tucson Tower and asked them to confirm - Tucson Tower had me taxi over so they could see for themselves...... (mods installed: K2U Flap Seals, Aileron Seals, Flap/Fuse Seals. Stabilator Seals, Flap Hinge Fairings, Slimline Strobe, 180 hp, Metco-Aire Wing Tips.


*Mike L. Gustafson July, 1997 PIPERS Magazine PA-28-140


I recently purchased a Knots 2U gap seal kit and wing root fairing for my Cherokee 180.  The gentleman who took my order was pleasant and couteous and it arrived within a few days. After installation I took my first test drive. I am pleased to report a 10 mph increase in cruise speed, maybe even a little more. In addition, as reported by several other testimonials I have read, I experienced much better aileron control during landing.  This also proved true during a steep (45 degree) turn. it is truly amazing!

Thanks for making an excellent product which meets or exceeds your advertising claims.


David W. Mapes


....Recently the rotating beacon on my 1971 Cherokee 140 bit the dust. I replaced it with the Strobe Kit from KNOTS 2U. Everything was just as advertised. My A&P said it was one of the most complete kits he had ever seen. I made the installation myself under the supervision of my A & P and it was easy.


*Martin J. Mary, April, 1996 Piper Owners Magazine


......My wife bought me a Stabilator seal kit for my birthday. I looked at the simple piece of aluminum and the handful of rivets. I could not figure out how this was going to make my PA-28-235 go any faster. After we installed the kit we took our first test flight. We could not believe the difference, and my wife was impressed with the smooth landings......


*Bill Daileda, December, 1996 Piper Owners Magazine


.....My 1980 Piper Archer couldn’t cut it here in high country....I ordered the KNOTS 2U Wing Root Fairings, Gap Seals, Hinge Covers, Beacon, and all new glass. The results were staggering. The Archer now lands on its mains and holds its nose up....KTAS has increased 8 - 12 kts minimum at all elevations and power settings of 60% & 65%. Fuel burn dropped from 8 gph on the hobbs to as low as 6.3 gph, and that includes those long climb outs.


*Kent P. Larsen April, 1994 Private Pilot Magazine.


.....Recently installed KNOTS 2U Flap Hinge Fairings, Wing Root Fairings, Flap Gap Seals, and Aileron Gap Seals. Based upon my Loran and DME readings. I have gained approximately 10 kts in airspeed.......


Walter D. Haskins June, 1988 Piper Owners Magazine.


.....Am pleased by both the effects of the mods, and by the quality of construction and installation. The mods seem to have increased cruise speed 10 kts, I am now consistently seeing true airspeeds in the 180-190 knot range.....the gap seals have also made an improvement in low speed handling.....I highly recommend the KNOTS 2U mods as a way of making the airplane even better.


*J.J. Miller September, 1992 Comanche Flyer PA-30


With the many K2U mods he has installed, Austin files for 175kts cruise, and most often trues out at 178 kts cuising at 7000 ft and 75% (compared to 160kts before mods) Austin’s comments about the performance gains were all positive, and he was equally pleased with the appearance of the K2U mods.


March 1998 PIPERS Magazine, Austin Cole PA-30 (Gap Seals, Rudder Seals, Wing Root Fairings, Gear Lobes, Arapaho W/S, Slimline Strobe)


..........I ordered the Wing Root Fairings and had them installed.  After retrieving the plane and forgetting on my first landing that they were installed,  I greased it on at Flying Cloud, MN, with good stab control all the way through the touchdown.  Well one landing didn't convince me of course,  but the next 8 or 9 did.  Granted they weren't all greasers, but they were far from the previous embarrassments.......

July 1999 Comanche Flyer,  Letters to the Editors.  Pilot Steve Bulwicz