This letter and photos came in from Spencer Gould. Some quick notes on his background are in a letter he wrote in the “Mail Sack – Stromberg” story. If you have one of our Zenith Install Manuals, his picture is right up front in the introduction as one of my Hangar Gang. In that paragraph I am pointing out that many experimental aviation companies are staffed by polo-shirt-clad salespeople while our crew has always been 100% hard-core aircraft builders. Spencer was my key guy for the CAD work that went into our 5th bearing and many of the Gold System Parts. He is no Troglodyte, he is an intensely driven very smart guy The design you see here was actually flight tested in a 1/4 scale RC model. Spencer flew it with a live video downlink in the plane focused on the left wing, which was tuff tested to look at the airflow pattern over it. Every layup in the plane has a structural calculation associated with it, nothing is eyeballed. The SP-500 is not your average homebuilt.-ww
(Note: Being a Troglodyte, I am not very good at posting pictures, and if the pictures take a while to load, it’s probably my fault, and I will have to ask Grace to fix it later. My neighbor’s dog Kirby will stare at you intently and appear to follow your every word if you look at him while talking about any subject, even degreeing a cam. Yet it would be unfair of me to be angry at him if I later asked him to degree a cam and he couldn’t. I ask that anyone temped to write me an e-mail starting with “resizing Gif files into Dfxl files is easy, you just…” not get angry later. It has been my observation that in the spectrum of mechanical people, Tribe Grease Monkey has always been willing to accept that the Tech-Geek tribe was just born different, and leave it at that. However, the Tribe Tech-Geek tends to have the feeling that the Grease Monkeys have just been deprived of the opportunity to become a Tech-Geek, and if they just patiently instructed Grease Monkey and used small words, he would see the light and trade his ball peen hammer collection in for an Iphone. It’s actually motivated by a beautiful view of human nature, that given the opportunity we are rational enough to “better” ourselves. unfortunately, Kirby was born a dog, and I am a born Troglodyte, and no one should be mad at either of us.-ww)
Here are some current photos of the SP-500 project. Since the early ’08 picture the wing primary structure has been completed. The wing is a constant chord NACA 63-618 that features a ring molded nose and tail rib with a very tight profile tolerance. The spar design has been computer optimized and utilizes Graphlight protruded carbon fiber stock for the caps and G-10 for all the point source load reinforcements. All the bonding operations in the wing were achieved with 1/8” cleco’s on a 2” to 4” spacing, alignment and bond constancy went off with out a hitch with no imprinting required. The fuel tanks are integral covering 3 bays (see the grey Jeffco coating below) with 2 suppression bays before the cockpit.
Below: The engine is a fairly Stock 2,700 cc (O-164). It’s all cocooned up in climate control right now, there is some minor work to be done before it can run but I do intend on getting a 5th bearing set up on it before I fly. I’ve learned a ton about engine building between the Colleges and all the help from you and the Hangar Gang. All those years of working on the TSIOF-550J FADEC installation for the PA-46 I think gave me some hints on the gold color scheme.
All the tail feathers, flaps, ailerons and wing tips are hot wired blue foam. The H stab is removable but the V stab is fixed.
Above, tailwheel assembly.
When I first started out in this project in ’06, I designed a couple machined components for Piper and had seen their CNC equipment in action but it was not until the hands on training you gave me on manual lathes and mills all those years ago at the old Edgewater hangar that the lightbulb really clicked. Since then I have manually machined many complex components on my Smithy for my plane including the tailwheel assembly and main gear/adapters. All this manual machining knowledge has proven to be very valuable on the P&W aircraft gas turbine work I do now.
Above: The seat crush structure and panels are now complete and I’m working on some trial and error work on the instrument panel (cardboard is my friend and makes for some free and easy prototyping). You can also see the wicked internal support system for the landing gear. It’s similar to a Wittman or RV style but its integral to the fuselage rather than the engine mount.
Below: There has been some coverage about my project on the FlyCorvair.com main Web site but I thought an up to date 3 view of the plane would be helpful:
Above: The wing butt rib showing the attach points that go into the spar box. Caps are carbon fiber .
Hope this has been an informative update on the project.
See you at Sun ‘N Fun 2011. Spencer
I typed “Lifestyles of Troglodytes” between 3 and 4 a.m. last night. Vern and I worked on Zenith Motor Mounts all day. He rode his motorcycle home at sundown to avoid the projected 25F temperature slated for midnight. I worked in the heated shop, putting crank and cam gears on a 2,700cc engine that will be run at Corvair College #22 in three weeks. At 10 p.m. Alex called and said he was going to have a late cookout. He is the sailer in the “Mail Sack – Sterling Hayden” post. It was a fun night with 10 people there, including a guy from England and one from South Africa. A lot of good conversation fueled by beer and interesting people. As I was planning on flying at dawn (the weather looked like visibility was going to be 100 miles), I was just drinking a small river of coffee.
I walked across the runway back to our place at 2 a.m. To wired to work or sleep, I spent some time looking at airfoils, toying around with shrinking the Tailwind chord from 48″ to 42″, getting the same spar depth in a 15% thick section, ending up with the same area, but several more feet of span and a better aspect ratio. The evening’s conversations had sparked a lot of thoughts, and I ended up typing the Troglodyte story. I looked at it for 10 minutes before sending it. Would builders think it was funny? Offensive? Plain old weird? I sent it after realizing that it is a little late in my life to suddenly get concerned about being thought of as weird or offensive by middle of the road types. I was too tired to fly at dawn, I went to bed instead. I got up when Vern came back at 9:30 a.m. By this afternoon, the counter on the story indicated that 535 different email addresses had been to the story. In came a long stream of letters, many of which required a lot of thought. Evidently it touched a nerve or a funny bone in a lot of people. As a final note, I want everyone to understand that I have many more friends that are Tech-Geeks than Troglodytes, and I meant no offense to people who are smarter than I am. Maybe one of you Tech guys could explain the hierarchy of the tech world, it would be entertaining, but please, use small words for us Troglodytes.
601XL builder and Pilot Andy Elliott, Phd, aerospace engineer from MIT wrote:
“As a long-time member of the geek tribe, I mention the classic book “Theory of Wing Sections,” Abbot and von Doenhoff, 1948, that is the standard reference for any of the NACA series airfoils. It includes both ordinates and performance data. It is republished by Dover Books in paperback and is available new from Amazon for <$16!
Another good resource it the Univ. of Illinois airfoil data base, which is found at http://www.ae.illinois.edu/m-selig/ads/coord_database.html. The Clark series are all there in high precision. Note that this database uses the geek-standard approach of providing the airfoil ordinates in the zero-lift orientation. This obfuscates the flat-bottomed nature of the Clark Y. Again, referring to old data to get away from modern misrepresentations, you can find NACA Report 502 online at http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930091575_1993091575.pdf. This report has the Clark Y coordinates in the troglodyte reference frame, that is with the flat bottom flat. There you can easily see that the airfoil is 11.7% thick! FWIW, Andy”
Andy, As an owner of a giant collection of aviation literature, I have most of the stuff you reference right on the back porch. believe it or not, the Clark Y is not in Theory of Wing sections. I have the Troglodyte ordinates in the back of a number of old books, but the references you mention are good assets. Thanks-ww
Builder Jerry McFerron wrote:
Hi William, I have written a program that will convert an Excel file containing the airfoil coordinates to an AutoCAD drawing of the airfoil in one second. The program could certainly use some “real world” testing if you are interested. Take care, Jerry.
Jerry, Thanks for the very kind offer, and I may take you up on it. Here is the only issue: I am a genuine Troglodyte of the first order, and I hate to say this in public, but I don’t know how to write up a spreadsheet on Excel. I would need some help from Grace on that one. I think that if I learn to use Excel, then I might be jeopardizing my status, and before you know it, people will start thinking of me as a Neandertal.
Tom Graziano, man of a thousand global aviation adventures, Super DC-3 owner, etc., writes:
“William, You’ll save yourself a lot of trouble by just getting a copy of Harry Riblett’s book GA Airfoils from the EAA. With a Riblett airfoil, you’ll end up with a superior wing. For a Tailwind, look at the GA35A413.5 and GA35A415 airfoils. You can draw out the ordinates & airfoil by hand – I’ve done it for a couple of projects (butcher paper works well) – or use a computer program. I use Compufoil. Works great! Cheers, Tom”
Tom, Great to hear from you. I have Harry’s book, read it cover to cover many times. The Tailwind has a real funky packaging problem at the butt rib because the root chord is choked down so much, and the area around the rear spar attachment and where the torque tube passes is generally not covered by the footprint of a lot of good airfoils. You can’t use a lot of them because with the correct angle of incidence they would be either too low for the door to open or too high to blend the cabin top and windshield into the wing. I’ll get a look at the two airfoils and see how they lay out.-ww
Harold Bickford, NE, writes:
“Quite a spectrum there William and a very enjoyable read. On the one hand I’m a geek in that I look to the soon to come day when 3D printers allow the fabrication of many parts useful in an airplane and at reasonable cost. Yet the building will still have to occur, however simplified. Still the Pietenpol (Neanderthal Aviation?) has an appeal as an old school, proven idea. The Corvair engine follows suit. Ditto ‘steam gauges.’
“Just like manually plotting an airfoil using accurate information, it is the engagement that makes the experience fun and a learning experience. Whether cutting and milling wood parts to precise sizes (and being willing to try again) or simply researching the engine numbers to determine which engine you really have, the activity becomes a means of involvement that uses all of the senses.
“It is not instant gratification by any means though the process does become continuing gratification as at every step some bit of learning and progress occur and then the stage is set for the next act in what is a real life adventure.”
Joe Goldman, Sprint builder N198JL from Florida writes:
“William, That’s the way my ribblett wing went. Harry Ribblet airfoil GA35U-A315 . Got a long 1/4″ luan plywood, made my center line and went one from the X column, one from the Y, and one from the Z…. Checked it many times. Looks good and allows for a straight up 8.7″ spar. Hope it flies like the original. Joe.”
“William, As a Captain for a major airline and an airline pilot for close to 25 years, I can appreciate your comments on flying and technology. I spent 4 and 1/2 years instructing glass cockpit jumbo jet training, and we worked hard to instill the concept of ‘automation download’. Simply put, automation download means that once the technology gets in the way of flying that keeps you out of risky situations, download to the next level. If necessary, download to the next level, whatever it takes to maintain safe control of the aircraft.
“How about an example? Say you are flying an airplane such as a 767 that has FMS and you set up the FMS to fly the ILS to 27L in ATL. It is in the box, and you are monitoring the systems while actually flying a Visual Approach to 27L. You call the runway in sight, and Tower offers you 27R since it is a quicker turnoff to the terminal. You accept the runway change, but now what? You download the automation, turn off the FMS (because reprogramming it requires a heads down cockpit- not good at 2000 AGL). You kick off the autopilot, and hand fly the aircraft down the PAPI that you see giving you great glide path info. In other words, you fly the airplane, not the technology. That is the trick – teaching pilots when to make that automation download decision, and avoid going heads down, trying to load the ILS 27R approach in the FMS, and ending up flying across the 26L final approach course (look at the ATL airfield diagram – yes that happened many years ago – unbelievable!). Just my thoughts on the subject. Keep up the great writing. You make me think.”
Rob Schaum, Murphy Rebel w/3,000cc Corvair builder writes:
“Yikes….that story is as scary as it is entertaining. You’ve alluded to this before in your writings, but I’m convinced that the greatest challenge any homebuilder faces is knowing which information sources to trust, and which ones to run away from…quickly. This process, for me, takes almost more time than building. It is compounded by the fact that I, like so many of us, am a part-time builder and cannot rely on an Embry-Riddle education – and decades of experience – to immediately identify the flaws in someone’s argument. Nevertheless, the process of screening out the good info from the bad is critical to our being able to one day confidently sit at the controls of our aircraft, lined up for takeoff, and push that throttle forward.”
Rob, Fear not, you can trust the things you read here, and over time you will develop more and more of a sense of good vs. b.s. info. BTW, did you see yourself in the group 2005 photo on the Dr. Ray Post? I’m pretty sure you’re in there.-ww
Hi William, On the subject of carburetors what make / model would you recommend for a low wing / fuel pump system like in a 601XL? & When is the next planned Florida Corvair College?
Thanks, Spencer (TGI) 2700 cc & SP-500 builder
Above, Spencer’s original Corvair powered design, the SP-500 single seat aerobatic aircraft. This photo was taken in 2008, the aircraft is far closer to being done today. In the meantime, Spencer has also switched jobs from Piper to Pratt-Whittney, become a homeowner, gotten engaged and beaten serious cancer. Some guys are just overachievers. Spencer is my cheif engineering resource and CAD guy. He has a completed 2,700cc already built for the plane. He is an Embry-Riddle Aerospace Engineer and he is working on commercial and instrument ratings.
Spencer: My first choice for any aircraft that is going to have pressure to the carb, not just gravity feed, is a Marvel Schebler MA3-SPA. Second is an Ellison EFS-3A. Our next Florida event is Sun ‘n Fun, my 24th consecutive year. If we are going to have a Florida Corvair College this year, we will announce it at SNF, but right now, I think Barnwell, S.C., in November is going to be the closest event for Florida builders. Please send us updated photos of your bird.-ww
Pete Kozachik, west coast Pietenpol builder, wrote: (Submitted on 2012/02/03 at 6:25 pm)
Thanks for the in-depth Stromberg piece; your explanation of the how and why carbs such as my particular unit have no mixture control puts to rest a concern I’ve had (and others I’ll bet). That’s empowering.
Thanks for your efforts getting this information out into the public domain. I considerate it a valuable service.
Which float needle are you using in the Strombergs: neoprene tip, steel, or delrin?
Dave, although the others seal better, I am a big fan of the all metal needle and seat because I think that it is the most tolerant of fuel additives of any of the combinations. If I were thinking of using auto fuel, I would stick with the metal needle, as there is no telling if they will blend something in your batch of car gas that will bother the delrin or neoprene.-ww
Dave saw his plane on the List of Flying Zeniths and sent us this letter and photos:
Above, Dave and his 650
Dave Gardea CH-650 N631DG 2,700 First Flight – 5/4/11
“N631DG now has 81 hours on the hobbs and would have a lot more except I was down for a few weeks last summer while waiting for my new heads from Falcon. My project Web site is at http://n631dg.t15.org/home.html
My YouTube video channel of the first and other flights is at http://www.youtube.com/user/dgardea11/videos
(Dave started flying on a set of heads that just had a simple valve job done on them. After one of them had a valve guide slip he got to learn first hand that Corvairs fly just fine on 5 out of 6 cylinders. At that point he went to a set of heads rebuilt by Mark Petz at Falcon machine.-ww)
“The engine I built includes Falcon heads, all your high quality parts, Niagara cooler, a Dan 5th bearing, nitrided crank, Marvel Schebler 10-4894 (Model MA3-SPA) carb, front starter, John Deere alternator, and a Warp Drive prop. I have never had the opportunity to attend a Corvair College. Larry Hudson in the Indianapolis area was a great resource during the build as well in addition to your detailed manuals.
I have also attached a few pics. Please keep up the great posts on the new flycorvair.net! “
Above, the 2,700 Dave built. The engine is straight out of our Conversion and Installation Manuals
Above, the rear view of Dave’s engine. Gold Oil Filter Housing and optional Sandwich Adapter feeding a heavy duty oil cooler. These components and the Baffle Kit from J.S. Weseman make a very clean professional look in the engine compartment.
Here is a sample of the letters we received on The James Stockdale – Philosophy story:
From Andy Elliott, 601XL builder and flyer, Mesa, AZ. (Submitted on 2012/02/07 at 9:11 pm)
“Regarding Admiral Stockdale – I heard Admiral Stockdale speak at a pilot graduation one year when I was a young LT. He was a truly impressive man. I was totally depressed by the performance during the vice-presidential debates, thinking that he should have taken those little men who were his opponents and simply vaporized them with the strength of his character, that they so clearly lacked. There is a Stockdale Center for Ethical Leadership at the USNA.”
From Stu Bryant, Atwater, California
“PP-SEL. and wanna-be homebuilder; the dream remains ALIVE!” (Submitted on 2012/02/07 at 4:12 am)
“There are just two blogs which consistently have enough substance to be worth my while to follow regularly. Each are penned by men who tend to swim against the current. Who else is bold enough to stray away from the well worn ruts to actually say something both significant & interesting? Both of you are patriots, and both deeply touched (as I have been) by the generation who fought the last world war. Thank you for all you do for the homebuilding cause, but also for your well spoken thoughtful musings of matters /significant/ in general. It is my increasingly curmudgeonly opinion (despite my age being within a couple years of yours) that most live life in the shallowest way possible. I find it refreshing indeed to see someone express something which transcends the merely selfish and comfortable in order to provoke both deeper thought and feeling. Life is wasted if we settle for less! Anyway, this was right on!”
Terry Hand, USMC aviator, wrote:
“I had just checked into the Training Command in Pensacola as a T34C Instructor in early 1987, when the entire Training Command shut down for one day. We all drove over to Mainside Pensacola to attend the Naval Aviation Association’s 1987 Symposium. The morning’s symposium was a discussion of the topic, “The Air War in Vietnam.” I will never forget the moderator’s first question posed to retired Admiral Tom Moorer, who had been Chairman of the Joint Chiefs for much of the Vietnam War in the Mid 1960s. When asked what he had learned from the Air War in Vietnam, Admiral Moorer’s reply was, “I didn’t learn a damn thing about how to conduct an air war in Vietnam. I knew how to conduct an air war. The politician’s just wouldn’t let me.” The cheers just about brought down the house!
The afternoon’s discussion was “The Code of Conduct, and its Effect on POWs”. Admiral Stockdale was one of several members of the discussion. The strength of character of the man was so evident as he spoke, and you knew that he was a man who had walked the walk, and not just talked the talk. His words were strong, heartfelt, genuine, and could be seen as having come from the crucible of his experiences. I had just finished reading his book, In Love and War, and, afterward, I wanted to shake his hand and simply thank him for his sacrifice as well as his words of that day. I was fortunate to shake hands with not only Admiral Stockdale, but his lovely wife Sybil. He spent a good amount of time speaking to myself as well as many other pilots and student pilots. I hung around til the end just to say one last goodbye, and as he walked away, I saw that he walked with such a limp, that I said to myself, “That man truly carries the scars of his service to this country, and bears them with pride and honor. What a man!” I have carried the memory of meeting him for almost 25 years now.
On a slight aside to the story, in the first publication you reference of Admiral Stockdale’s discussion of Stoicism, he mentions that his wingman on one of his cruises was a young Marine Lieutenant Duane Wills. I knew him almost 20 years later as Colonel Wills, and he was my MAU (Marine Amphibious Unit) Commander in 1984 and 1985 while deployed aboard the USS Tarawa in WestPac. I had the privilege of flying with Colonel Wills many times during that deployment, and he was another fine Officer and Aviator. I just did not know until I read that paper that I was only one degree of separation from Admiral Stockdale!
I hope that all of this only serves to motivate you to keep writing of the things that you care about in Aviation, because there are many of us that can and do relate to what you write. Thanks again. Semper Fi”
Note: The time stamps on this web page are in Zulu time (GMT).
Below is a partial list of Zeniths that our builders finished and have flown. I am still combing our records to bring all the data to one spot. A handful of the first flight dates may have the wrong month, please feel free to write in with any correction or addition. My intention is to gather the info and use it to update our page on the Official Zenith builders Web site. Grace is out of town with family for a few days, so the errors or omissions on this list are mine. Many of you know that Grace has a phenomenal memory and could have typed this data out directly from her head. Between Grace and some help from builders, we should have an accurate list shortly.
When looking through the information, the first thing I thought is that it is a large body of work. It is quite a success story. There have been a lot of alternative engines that got a lot of play in the aviation media that never ended up with this many planes flying total. Here we are just looking at the Corvair powered planes from a single airframe brand, albeit a very popular brand. These builders put in a lot of work to reach the finish line, and we were very glad to play a role in their success. If we were just a buy-it-in-a-box engine company, these names would just be a list of consumers. Because of the nature of the Corvair movement, the builders listed all learned a lot more about engines, have much more pride in their planes, and a greater degree of achievement at the finish line. When you think about what these builders knew and what they thought they were capable of before starting, and then contrast that with the same people the day their planes flew you are looking at the real body of work. Speaking with Chris Heintz at Oshkosh last year, I said that the planes that are built are hardware, just the end result of the real project, each builder working on himself, improving his skills, capabilities and expanding his belief of what he can do. He smiled and agreed that this was the fundamental value of homebuilding.
This list has planes on it that are not flying today. One of the best known Zenith/Corvair pilots on the list is Scott Laughlin. His aircraft was the first plans built 601XL. He had never built a plane nor an aircraft engine before, and was not a pilot when he started. He had a lot of great times in his aircraft, some of which can be seen on YouTube videos. After flying about 200 hours he kindly let another pilot try a landing in the plane. It was damaged so badly that Scott took the plane apart, and sold off the pieces. Hopefully time will see Scott’s return to another round of homebuilding. The list also includes 2 planes that have moved to a different engine. There are several other aircraft that have flown that we will add later, so the total aircraft number is a good representation. When the list is compiled, I will write up a set of notes on each aircraft, and include photos of each of the planes. For right now we will start with the basic list.
We have a list, far longer, of builders who could finish and fly their Zenith before Oshkosh this year: Ken Pavlou, Larry Winger, Patrick Hoyt, Jeff Cochran, Thomas Siminski, Gerry Scampoli, Larry Webber and Ron Lendon are the first names on this list that pop into my head. You can get a good idea of the number of builders close to the finish by looking at the pictures of running engines in our Corvair College albums. This effect is continuous, in 30 days we will be at Corvair College #22, and we have already lined up four engine runs for the event. All of these are going into Zenith airframes that are largely complete.
We have a third wave, just as important, who have been chipping away at their project for a number of years. A number of these guys were slowed by a move, a kid headed to college or a change in jobs. I know many of these builders just as well from having them at Colleges and making house calls to their shops. People outside the Corvair movement are often mystified by some of our most vocal supporters. Many of the people who go out of their way to say something positive about our work are in this third group. This is because I take their project seriously and treat them just like builders with more available time or funds. Every aviation LLC takes your project very seriously when you are in their booth at Oshkosh with your hand on your wallet. The outfits that are here for the long run take your project seriously all the time. We are here for the long run and I look forward to adding your name and N-number to this list of successful builders.
Builder’s Name Model N-Number Engine 1st Flight
William Wynne 601XL N1777W 3,100 May ’04
Greg Jannakos 601HDS N4399 2,700 June ’05
Randy Stout 601HD N28RS 2,700 May ’05
Gary Ray 601XL N24845 2,700 Sept. ’06
Phil Maxson 601XL N601MX 2,700 Mar. ’06
Brandon Tucker 601HDS N601XT 2,700 Nov. ’06
Rick Lindstrom 601XL N42KP 2,700 Nov. ’06
Cleone Markwell 601HD N998ZZ 2,700 Mar. ’07
Dave Harms 601XL N618PZ 2,700 June ’07
Charles Leonard 601XL N920EL 2,700 June ’07
Murray Rouse 601XL N47186 2,700 Oct. ’07
Ken Smith 601XL N601KS 2,700 Nov. ’07
Scott Laughlin 601XL N5SL 2,700 Jan. ’08
Woody Harris 601XL N734WH 2,850 Feb. ’08
Sandy Crile CH-701 N9569S 2,700 Feb. ’08
Lincoln Probst 601XL C-GXLP 2,700 Apr. ’08
Scott Thatcher 601XL N601EL 2,700 May ’08
Steve Mineart 601XL N164SM 2,700 July ’08
Lynn Dingfelder 601XL N4ZK 2,700 Oct. ’08
Jay Bannister 601XL N2630J 2,700 Oct. ’08
Andy Elliott 601XL N601GE 3,100 Nov. ’08
Ray Griffith 601XL N614RK 2,700 Dec. ’08
Al Barnard 601XL N472AB 2,700 Dec. ’08
Zersis Mehta 601XL N601ZM 2,700 Jan. ’09
Louis Cantor 601XL N601LV 2,700 July ’09
Gary Thomas 601XL N124GT 2,700 July ’09
Dave Coberly 601XL N601XZ 2,700 July ’09
Rich Whittington 601HDS N601RW 3,000
Shayne & Phyllis McDaniel-650 N5880Z 2,700 July ’10
Rich Vetterli 601XL N56DV 2,700 Sept. ’10
Doug Stevenson CH-750 N632DR 3,000 April ’11
Lathrop/Neff 601XL N601LN 2,700 April ’11
Dave Gardea CH-650 N631DG 2,700 May ’11
Alan Uhr 601XL N15AU 2,700 Mar. ’11
Roger Pritchard 601XL N20RB 2,700 Oct. ’11