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Sonex Letter to the Editor of Kitplanes Magazine

The following is Sonex Aircraft, LLC's response to the July, 2007 Kitplanes Magazine article "Waiex, Y Not?" While the article contained a lot of positive information, Sonex Aircraft, LLC disagrees with some of the negative statements made by the author.

Following the Letter from Sonex Aircraft, LLC is a letter to Kitplanes from Lou Pappas, the owner of the aircraft reviewed in the article.


We are writing to express our disappointment in the "Waiex. Y Not?" Flight Review Article that appeared in the July 2007 KITPLANES. In our opinion, the author has completely missed the mission our family of aircraft were designed for. The author also appears to have had a pre-conceived notion that there was something in the handling that he was not going to like and he went out of his way to find it.

First, to review some of the positives in the article. The author does a great job hitting on the tremendous value that the Sonex Family offers. The continuing mission of Sonex Aircraft, LLC is to deliver as much performance as we can for as little money as we can. The author also does a great job clarifying with performance numbers "Max Speed" Component of the Light, Sport Aircraft Rules. We also feel the first 5 sections are extremely positive and provide highlights of the building experience of Lou Pappas that is the norm in the Sonex Aircraft Builder Community. It is a glowing real account of how a builder should prepare themselves for building and the first flight experience.

Next, we have one minor and one major correction to the article that we would like to respectfully request be printed in the next KITPLANES Magazine.

First, In the "An Early Adopter" ,first paragraph, it suggests that the Waiex can be built from plans which is not correct. The Waiex can only be built from a complete Airframe Kit. The Sonex, however, can be built from Plans and purchasing the proprietary wing spar caps.

Second, while it is one author's opinion to characterize even some of the Waiex handling qualities as "outside the accepted range" it is an opinion that is not only misleading, it's just plain false. To make a statement like this insinuates that somehow the aircraft is not fit for any pilot to fly and should be grounded immediately. This is irresponsible journalism. It serves as a warning to current and would-be Sonex or Waiex Customers that they should look elsewhere for their Sport Pilot Aircraft. With thousands of fleet hours on the Sonex Family of aircraft worldwide, we need only to refer the KITPLANES Editorial Staff and the reading public to the growing hundreds of positive flight reviews and comments made about our line of aircraft (many of them posted to our own eGroups) to justify a retraction to this very misleading statement. We have included a sampling of these comments at the end of this letter.

On to some other negative comments in the article that we feel must be directly responded to.

Under the heading of "Quick in More Than One Way", the author suggests that the Sonex Factory Aircraft that was flown in has "sensitive handling in pitch and especially the landing". I am not sure if the Author and I were flying in the same airplane on the same day, but our interpretations of the
handling of the Sonex could not be more different. I find the Sonex to be a wonderfully handling aircraft that can and should be flown by low-time pilots. I do not recollect hearing any handling quality concerns expressed by the author. Had they been expressed, I would have been happy to take the time to give the author a more thorough flight evaluation and go through any of these concerns particularly as they relate to trim settings.

Most any aircraft would be considered sensitive if it is exclusively compared to a certified aircraft fleet designed for a completely different audience and completely different mission. The Sonex, Waiex, and Xenos are by-design more sensitive and sporty than any of the certified aircraft fleet. They provide an immediate high "fun-factor" WITHOUT compromising a thoroughly controllable and comfortable feel for the pilot.

In the second paragraph under the heading of "Quick in More Than One Way", the author asserts that he has some kind of "Golden Touch". I must admit that I cannot possibly agree that a pilot can claim to have a "Golden Touch" if they have trouble maneuvering the Sonex, Waiex, or Xenos. The most common correction I have made to anyone flying in one of our factory aircraft for the first time is to "please release your strong grip on the stick and fly with two fingers". The next most common correction I have made is to politely ask the passenger to remove all force from their feet on the rudder pedals and replace it with a very light touch." In every case of flying with someone, they have quickly and easily made the adjustment and remark about how sweet our little airplanes are to handle. I will make the direct assertion that most if not all of the over-controlling and resulting negative handling qualities were being induced by the author.

Next, on the static stability tests. This is where we have found to be the most common area of misunderstanding on the Sonex Family of Aircraft.

Sonex Aircraft, LLC does not have any personal experience with the aircraft that was reviewed in this article. There are many factors that could play into the static stability profile of this airplane. We would have to do a thorough examination of any builder modifications or customizations made that could impact the handling. We do believe that the author misunderstands the trim set-up of this particular aircraft which led him to some incorrect conclusions.

We would like to provide some background information to all KITPLANES readers so they can better understand pitch stability in Sonex and Waiex Aircraft.

The original Sonex Trim System which continues as the Standard Sonex Trim System, utilizes a small tab attached to the elevator. This tab is controlled with a mechanical push/pull lever. This system is very responsive and simple. The primary advantage is the immediate trim input that can be provided by the pilot. The primary disadvantage of this system (in one flight reviewer's opinion) is that if you deploy full flaps in the Sonex, and move the trim tab to the full aft position, the pilot still is required to hold some back pressure on the stick to hold a set pitch attitude. This is a result of a trim tab size compromise to fit the Sonex's very wide speed range.

The newer Sonex "Dial-A-Speed" system was developed specifically for the Waiex and Xenos which do not have a horizontal control surface to attach a tab to. This system is designed to "Dial In" a set elevator position for a specific trimmed attitude. It accomplishes this with two springs that load the elevator controls in opposing directions. The pilot then provides up or down trim by further loading the "pitch up" or "pitch down" spring. The "Dial-A-Speed" System is ideal for the pilot looking for more of a "hands off" flying aircraft where a particular speed can be selected by turning the mechanical pitch trim dial. In the Sonex, we've observed one full revolution to result in an approximate 2 mph speed difference. As with any aircraft, a change in the aircraft's speed either by throttle application or pitch input will require a change in the trim setting.

The "Dial-A-Speed" Pitch trim instructions provide guidance in setting up an initial pre-loaded setting for the springs. It is up to the builder to adjust the spring tension as necessary to achieve balance between the "pitch up" and "pitch down" spring and set these springs to fly hands off if they wish.

We should also note that the "slop" observed in the elevator linkage on the reviewed airplane likely came from a stick that was modified to be removable by the builder. This fact is not mentioned in the article.

The final paragraph of the article contains the most disturbing comment when the author states that the Waiex's "unwilingness to return to trimmed airspeed... Will result in higher workload, particularly in turbulance". None of the hundreds of pilots and passengers in our family of aircraft have reported any higher workload than any other aircraft...including certified aircraft. This statement should not have been included in this article.

Sonex Aircraft, LLC has never and will never suggest that any of our family of aircraft should be considered as IFR Platforms. Sonex Aircraft, LLC makes every effort to educate potential customers on the mission our aircraft were designed for and what our philosophy is on sport flying. If our team of designers were to take on an "IFR Platform" Aircraft, it would look very different and fly very differently than our current product "IFR Platform" Aircraft would not be nearly as much fun to fly!

We were very disappointed that this article was written by an author who seems to not only lack the appropriate qualifications, but also does not understand or tolerate sport handling qualities in any aircraft. If allowed to go unchecked, this opinion could serve to damage many a company's reputation that was not as established and well thought-of as the Sonex Aircraft Fleet. We would be curious to see this author's review of other widely-accepted "sporty" aircraft designs such as the Pitts Special, Sonerais, KR Series, or any Van's RV. Contrary to the author's ideals, if every airplane flew like a Cessna, recreational aviation would become pretty boring.

We hope that perhaps future negative handling articles on sportier handling aircraft can be avoided by only conducting flight reviews of Factory Aircraft with Qualified Factory Aircraft Test Pilots and Engineers.

Perhaps an even better approach for future KITPLANES flight evaluations would be to pick a group of builder/pilots of a specific type and ask them specific questions like:
-Does this aircraft perform per the factory specifications?
-What do you like about the airplane's flying characteristics?
-What don't you like about the airplane's flying characteristics?
-Did this airplane meet your expectations?

We feel these alternative approaches would give KITPLANES readers the kind of information that aid potential builders on what kind of airplane they would like to build instead of one individual's impressions based on a single limited flight experience.

Below are some thoughts from Sonex and Waiex Pilots that were taken from one of our Sonex eGroups. All of these messages were in response to a potential Sonex customer who was made a posting questioning his decision to purchase Sonex Aircraft based on this KITPLANES Article.

Please feel free to contact me directly with any questions or comments on this letter.

Jeremy Monnett
Sonex Aircraft, LLC

Mon Jun 4, 2007 9:24 pm

After reading the Kitplanes article written by Ed Wischmeyer, I sent the following to the editor:


I read with interest Ed Wischmeyer's article on the Waiex in the July 2007 issue. I'm a low-time private pilot with 450 hours in my Sonex and one hour in a Sonex factory Waiex. During the many dozens of rides I've given in my Sonex I never saw one PIO. A quick explanation that they weren't flying a Cessna and to think stick pressure and not stick movement was all it took. I'm no test pilot
and probably don't understand much about pitch divergence and stick forces , but I do know that flying a Sonex/Waiex is not nearly as difficult as Ed makes it out to be. Stop by here and search the archives for 'first flights' to get a feel for how others feel about the Sonex/Waiex handling qualities.

Tony Spicer
Re: [sonextalk] Kitplanes Waiex Review
Mon Jun 4, 2007 9:12 pm
Daniel Weseman

I guess i need a copy of the kitplanes article? you really need to get a demo flight from someone near you! I'm in north Fl and if we both fit in it ill take ya up and you can fly it yourself (that goes for anyone interested!) I'm sure someone is near you and would be glad to give you a flight. I love the way N183SX handles and cant wait till the wind dies down so i can go flying. My next flight i will break the 100hr flight time mark and i seem to like it more each flight. Sonex LLC is a great company etc... but the best part of the sonex is how it flies! try to get a demo and see for yourself! fly smart and have FUN
Dan Weseman
Re: Kitplanes Waiex Review
Mon Jun 4, 2007 10:08 pm
"Jim Cunningham"

This question comes up all the time, as you'll see if you search the archives. These airplanes are more sensitive than the typical Cessna 152, but are not hard to fly. Remember-- Sonex wants to sell as many of these as they can and making a product that's hard to fly is not going to accomplish that.

If the Kitplanes folks think the Sonex family of aircraft is difficult to fly, then they'd better stay away from the Diamond Katana/Eclipse series, and the Diamond Star as well. I instruct part time and my school just got some of these a year ago. The Eclipses (the 2-place trainers) handle just like a Sonex in pitch. For what it's worth, students transitioning from our beat-up Cessna 152 into the Diamonds go "Whoa!" the first time they rotate on takeoff, and after 2-3 hours flying the airplane have everything smoothly under control.

It's just different! If you learned to fly in a Sonex or something similar and then got into your average Cessna or Piper, you'd find them sluggish and requiring lots of "oomph" on the yoke... until you got used to it.

Sonex 584
Re: Kitplanes Waiex Review
Mon Jun 4, 2007 10:28 pm


In the message above me Jim mentioned the Diamond DA-20 (Eclipse/Katana). You of course are asking about the Sonex and many reference the Cessna 150. I'm a 200 hour pilot so still fairly new but I have time in all three of these airplanes, admittedly though just one flight in a Sonex.

I started my flight training in a Piper Tomahawk and after 13 hours of that changed to the 2-place Diamond. I immediately loved the stick control and responsive handling of the Diamond and spent the next 36 hours of my training in it loving every minute.

When the training was over, the most economical way for me to get immediately in the air was a C-150 (19k vs. 175k for the Diamond). I really like my old classic 150 but my first flight in it was waaaaay different than that Diamond. I had really gotten used to the performance and it was, as someone said, like stepping out of a sports car and back into the Family Truckster.

Several months ago Dan was kind enough to give me a ride in his sweet Sonex (Cleanex) and man, I loved it immediately. It really reminded me of the Diamond handling but even more sporty to be honest - and I mean sporty in a good way. That airplane pretty much went where I pointed it. Another of our buddies here, Chris, has told me that he sometimes throttles his Sonex back and enjoys docile slower flight so that's an option too I guess.

Anyway, I've rambled on too long but to summarize: I love my 150 but can't wait till I get my Sonex done.


Re: Kitplanes Waiex Review
Posted by: "Mike Singleton"
Tue Jun 5, 2007 6:48 am (PST)

I agree with all the responses so far but can add a bit from my trip home from SWRFI this weekend. I climbed above the low clouds and cruised home at about 4500 feet where the air was smooth and cool. Just out of curiosity, I trimmed everything carefully and let go of the stick and pedals, then started the timer to see how long it would take before I diverged from level flight to over 200fpm rate of climb or descent, or more than about 30 degrees of bank. I did this twice and both times were just over 2 minutes. This may seem short but sit there and time that while you stare at the computer. You'll see that you can easily read a chart, adjust radios, or did in the baggage compartment for a bit without the plane going crazy.

Even in "normal" conditions, you will learn how to do that without any real problems.

Re: Kitplanes Waiex Review
Posted by: "Bruce Harrington"
Tue Jun 5, 2007 9:48 am (PST)
Hi Mark,

One reason I don't subscribe to Kitplanes is because of articles like the one you mention. There have been many first time flight reports on "Sonextalk" by low time pilots. Read anything from Jeffry, who started as an Ultralight pilot, earned his Sport Pilot rating, then went almost directly into flying a Sonex.

Many Sonex pilots have flown from either coast or Florida to Oshkosh. Tony Spicer, first customer completed Sonex, has flown many times to Sun-n-Fun and Oshkosh from the East Coast.

I'm 70, completed Sonex N321SX in May 2003, and went direct from a Rotax 582ed Kitfox IV-1200 (800+ hours) to my t/w Sonex with Jab 3300. I did first flight and all PIC since. I've flown many cross countries from Roseburg, Oregon. Round trips to the Sacremento, CA area around 700 miles; McMinnville, OR 260 miles r/t; Oregon Air Tours of 6 days and 1200+ miles; etc.. If I spend too much time folding and switching charts, I may be climbing or descending, but this only after much more than 30 seconds.

The Sonex and Waiex are flown with finger pressure, very much like the Van's RV series of homebuilts. You should have no problem flying a Waiex.

Bruce N321SX, Jab 3300, 164+ hrs
Re: Kitplanes Waiex Review
Posted by: "Mike January"
Tue Jun 5, 2007 4:02 pm (PST)

Hi Mark,
I am a very recent Waiex pilot who has read the article your talking about. I CAN NOT agree with all that pilots thoughts on the Waiex. I have well over 5000 hours of fixed wing time and another 1800 rotor and 16 hours in my Waiex tri gear Aerovee and over 10 in a Jabiru powered Sonex. The aircraft are a dream to fly. They were stable in all zones, very easy to land and to date, have shown no bad habits and I spent a lot of time looking down at my test matrix without wandering all over the sky. Yes, it is a very responsive aircraft however, I have never even approached a condition where I thought the aircraft over controlled or where pilot induced oscillation was even remotely evident. I have flown over 130 different aircraft in my over 41 years as a pilot which includes time as a flight instructor and all that I can say is that the Sonex is a very easy and forgiving aircraft to fly and was a fun build. It would be an easy aircraft for anyone to fly. As a matter of fact I have started construction on my next aircraft, a Sonex conventional gear serial number 721. If there were any problems with the aircraft or the company, I sure wouldn't be building another one. it's a great aircraft.

Waiex 23
16.8 hours
Re: Kitplanes Waiex Review
Posted by: "daleandee"
Tue Jun 5, 2007 7:20 pm (PST)

Mike sure has a lot of experience to back up what he says. I have about 600 hours of UL time in various ultralight type aircraft and did a lot of instructing in Challengers before my Sonex. I have also flown and done some training in GA aircraft including Pipers, and Cessnas.

I was a bit concerned about how the Sonex would handle before my first flight. I'm still in phase one flight testing with only a few hours but I gotta tell you the truth ... I can't wait to get back in that airplane! It is responsive but not "twitchy" and it is the easiest airplane to land that I have ever flown. I do have a nose wheel but my point is that so far I have never felt that the airplane was going to slip away from me and never a hint of PIO.

Get a ride in one and decide for yourself. Wayne Andrews in NC gave me a ride in his and now I have my own. It will happen to you too!

Dale Williams
Sonex # 533
Re: Kitplanes Waiex Review
Posted by: "charlie4_66043"
Tue Jun 5, 2007 7:31 pm (PST)

I got my Kitplanes mag today and read the Waiex article. I tried to compare what the author was describing to what I feel in my Sonex and what he experienced is not what I'm seeing. However, each handbuilt airplane is subject to some variation so I have to concede that his report could have been accurate...for that particular plane.

The main issue that I would address to the author is his comment about the Waiex/Sonex not being suitable for an IFR platform. I think he's right about that...but what he considered to be marginally unstable, I would describe as being "sensitive". My Sonex goes where I point it...and I don't turn loose of the stick and let it wander off on its on. When I reduce power the nose drops...takes noticable back pressure to hold the nose at the same attitude. When I drop flaps it goes even more nose heavy...but it still flys just fine with a moderate amount of back pressure. Pitch control is very precise with NO tendency to PIO. Landings are always nice three pointers unless I do something dumb. Like the author said in his article...I think he was just having a bad day.

Re: [SPAM] [sonextalk] Re: Kitplanes Waiex Review
Posted by: "Mark Bridge"
Tue Jun 5, 2007 7:32 pm (PST)

Thank you all for both a swift and multiple response! I find it reassuring that ALL who responded were in disagreement with the evaluation in Kitplanes. Because I found all info (both in the press and on this site) was positive, I was mystified at such a bad review. When I re-read the article, the reviewer seemed sooo negative, I suspect that he had either preconceived ideas about the Waiex or some personal agenda - the whole thing just didn't seem to jive with everything else I'd heard. I'm relieved and still very positive about the Waiex J Maybe on the 4 1/2hr drive to my parent's house this weekend (60th anniversary), I'll stress how this could be less than 2hr in a Sonex!

Thanks again for all your responses,


PS Dan - Thank you very much for the offer of a ride. I live in Northern Ontario, but I vacation in the Bradenton area at Christmas. If I don't find someone in my area, maybe I can see your A/C when I'm down some time.

PPS Tony - I LOVE your DVD - certainly inspires me to get into the act!
Re: Kitplanes Waiex Review
Posted by: "Tony Lewis"
Tue Jun 5, 2007 7:48 pm (PST)

You said everything I wanted to say.
I just would like for hundreds of us to write to the editor of Kitplanes.

Tony Lewis -Sonex #447
676 hours in one fine flying little fighter plane.

Letter to Kitplanes from Lou Pappas, owner of the aircraft reviewed in the article:

I thought I should respond to Ed Wischmeyer’s article and flight evaluation on my Waiex, in your magazine recently.  I would hope that you would print my response.  There are a number of errors and incorrect observations in Ed’s article.  I think I’ll just list them:

  1. I do not own 2 Mini Coopers, I own one 2005 convertible S model.  It has its original factory paint, Hot Orange Metallic, and I painted my Waiex the same color.  I did have an original Mini, 35 years ago.  Ed must have mis-read his notes.  I never told him that I currently had 2 Mini’s painted the same.
  2. Ed stated that he caused a pilot induced oscillation after taking the controls.  He did not.  I used one notch of flaps on take off.  During the climb out, after Ed took the controls, I manually removed the last notch of flaps which caused a normal pitch variation like any other airplane would.  Ed looked at me, I looked at him, and smiled.  I assumed he saw me reach for the flap handle and change the setting.  He made no mention during the flight or afterwards that he thought there was a PIO.  If he had said something to me, I would have realized that he did not observe or recognize the change in flap setting and clarified it for him.
  3. Ed stated that I flew the airplane with my left hand on the stick and used my right hand to reach across to control the throttle.  Not correct.  Left hand throttle, right hand stick.  I did on one occasion reach across with my right hand to set the friction knob on the throttle quadrant, but I always fly right stick, left throttle.
  4. Ed declared that the “elevator linkage” on my airplane had 1/8 inch of “slop” in it.  This is also untrue.  During the preflight interview, I told Ed that I made the right hand stick removable.  (Ed flew from the right side.)  This is my personal modification from factory plans.  The right stick is sleeved and is removed by withdrawing a single quick release pin.  If Ed had written that the right “stick” had 1/8 inch of slop, he would have been accurate.  Again he made no mention of it during the flight or after.  He just diagnosed without investigating.  If he had voiced any concern during the flight or after, I would have reminded him of our previous conversation.  I usually remove the right stick because I like the extra seat room for “stuff”.  I don’t fly from the right side, and don’t care about the right stick.
  5. Ed is correct in reporting that the trim was fully forward during our flight and that he was unsuccessful in his phugoid test attempts.  However, this airplane had just over 40 hours on it when we flew it and this was the first day that it carried 2 passengers.  Two 200 lb passengers at that.  During the phase one test period, I adjusted the new Sonex  “Dial a Speed” trim system spring locations for my weight and it performed flawlessly.  It was apparent that with two 200 pounders in the airplane, as well as less than half fuel, the trim mechanism needed to be repositioned on the ruddervator torque tube for more down ruddervator force..  This has been done.  At least Ed did mention in the article that this may have been the cause. But it was the only beef that he actually asked me about after the flight.
  6. Lastly, what was Ed thinking when he even bothered to mention IFR in the same sentence with any Sonex aircraft?  Even if he did just get done shooting approaches in his Cessna he couldn’t possibly be so uninformed as to think that the Sonex would ever be construed by anyone to be an IFR platform?  These are strictly VFR, fun, yank and bank, sporty airplanes.  Some of us enjoy hands on the stick, make stuff happen kind of flying.  A Cessna, yawn, is not something most Kitplanes readers aspire to owning.  What writer would compare the two?

I have been reading Kitplanes for ages.  I have relied on what I considered to be the impartial, accurate, aviation information I get from it.  I still choose to believe that the writers will ask questions and investigate the actual reasons an aircraft does what it does.  In this particular case, Ed did not.

I’m sure Ed is a fine guy, but he did seem to come into this evaluation with some preconceived ideas about Sonex and the Monnet’s.  Even before the flight, he used the phrase, ”well, the Sonex is one company’s vision of what a sport aircraft should be”. A phrase he used in the article.   He said that with a slight hint of disdain in his voice.  I should have picked up on it.

Lou Pappas
Waiex 31
“The Fastest Waiex on the Planet”

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