THE COZY NEWSLETTER #15 October, 1986

Published quarterly (Jan, April, July, Oct.) by

Co-Z Development Corp.
2046 No. 63rd Place
Mesa, AZ 85205
(602) 981-6401


It is mandatory for all Cozy builders to subscribe to this newsletter, as this is the only formal system we have for communicating plans changes and/or corrections, builder hints, changes in suppliers, and other information required by or of interest to builders. Builders will require newsletters from #4 on. When writing to us with questions, please send along a stamped, self-addressed envelope if you wish a personal reply. Allow space after each question for the answer. If you call, you can reach us most of the time on (602) 981-6401, which is both our office and residence number. If we are away (we will be away over the Christmas holidays), please leave your message on our answering machine, and we will return the call at our first opportunity.

The following prices are in effect:

       Information kit                      $9.00
       Newsletter, per year                  5.00
       Plans & Constr. Manual              230.00
       Owner's Manual                       15.00
       Extra set A drawings                 15.00
       Cozy decals, ea.                      5.00

We do not accept credit cards, because of the extra expense and record keeping involved. We do accept personal checks on US banks and money orders in US dollars.

Overseas orders for plans will be shipped by surface mail at no additional cost, but it takes a least 8 weeks. Airmail postage overseas averages about $30.00, because the plans weigh 6-1/2 pounds.

Our computer has a limited number of spaces for your address. If yours is an unusually long one, please supply us with the shortest acceptable abbreviation. Our computer is programmed to print on the label after your name, the newsletter expiration number, to remind you when to renew. The number at the top is a file number important only to us.


Uli and Linda Wolter (Co-Z Development - Europe)
Ahorn Str. 10A
D-8901 Ried, West Germany


When you receive your plans, please do the following:

  1. Sign both copies of the license agreement (Chap. 1, p.4) and send both to us. We will assign a serial number (required for licensing), sign one of the copies and return it to you for your records.
  2. Check the number of pages in each chapter against the number of pages listed under "Table of Contents". If any are missing, write to us for copies.
  3. Mark in all of the changes and/or corrections published in newsletters #4 to date.

There may be some things you don't understand on the first reading, particularly if you haven't started work yet. Don't immediately grab the phone. Usually when your construction reaches that point the instructions will become clear, if not on the first reading, at least on the second.

Some of you have cut up your large size A drawings and no longer can refer back to them. We have had additional copies printed, and can sell you an extra set as listed above.

Thank you for compliments we continue to get on the plans. It makes our efforts seem worthwhile.


We try to catch most of the articles on the Cozy, but occasionally miss some. Here are a few recent ones:

The Cozy also made the 1987 EAA calendar, although they goofed and showed the Long EZ in the small insert at the bottom.


Our current approved suppliers are as follows:

  1. Construction materials
    • Wicks Aircraft • 410 Pine St. • Highland, IL 62249 • (618) 654-7447
    • Aircraft Spruce • Box 424 • Fullerton, CA 92632 • (800) 824-1930
    • Alpha Plastics • 8734 Daffodil • Houston, TX 77063 • (713) 780-0023
  2. Metal Parts
    • Brock Mfg. • 11852 Western Ave. • Stanton, CA 90680 • (714) 898-4366
  3. Canopy and windows
    • Airplane Factory • 7111 Brandtvista Ave. • Dayton, OH 45424 • (513) 849-6533
  4. Cowling & Turtleback
    Main gear & Nose Strut
    • Feather Lite • P.O. Box 781 • Boonville, CA 95415 • (707) 895-2718
  5. Propellers
    • Great American • 1180 Pike Ln.#5 • Oceano, CA 93445 • (805) 481-9054
    • B & T Props • 3850 Sherrod Rd. • Mariposa, CA 95338 • (209) 742-6743
  6. Exhaust Systems
    • Sport Flight • 22267 Powell Rd. • Brooksville, FL 33512 • (904) 796-1874
  7. Antennas
    • Radio Systems Technology • 13281 Grass Valley Ave. • Grass Valley, CA 95945 • (800) 824-5978
  8. Scale-model Cozy
    • Avalon Designs • 25506 Crenshaw Blvd. • Torrance, CA 90505 • (213) 326-2892

There are a number of custom shops who advertise that they will build any or all parts for the Cozy.


Newsletter #14 was published one week before Uli's scheduled departure for Germany in his Cozy N52CZ. Uli is a very excellent builder (Grand Champion Kerrville 85, best Cozy Oshkosh 85), a very excellent pilot (NATO instructor check pilot), and a very methodical person. In preparation for his flight, he thoroughly checked his engine installation, and moved the fuel pressure sender from the carburetor (as shown in the plans) to the firewall (design change in NL #14). He installed vortilons, special brake discs and 600 x 6 calipers (NL #14), Loran (with antenna in the winglet), and an HF radio (required by Canada). He built an auxiliary fuselage tank of 25 gal. capacity (which he really didn't need, but wanted for insurance if he had to overfly one or more of his stops), and borrowed special cold water survival gear from NATO. The latter included a super wet suit, raft, etc. He intended to build new wheel pants before he left but time ran out, so he made the trip without pants.

Uli left Wichita Falls on July 3rd (I hope I have all the dates right) and flew nonstop to Buffalo, NY. The next day he flew to Montreal, where he passed his radio check out. Then it was on to Goose Bay, where he spent the weekend, because there are substantial landing penalties in Greenland and Iceland over the weekend. On Monday, July 7th, Uli flew from Goose Bay to Greenland in good weather. On Tuesday, he flew from Greenland to Iceland, running into bad weather about 200 mi. out. He had to make an ILS approach and landing. Wednesday he flew from Iceland to Scotland, again encountering IFR conditions (rain and icing), and had to make another instrument landing in Prestwick, Scotland. Then on Thursday, he flew from Scotland to Germany. During his crossing, he didn't call back home, so we all were in great suspense. In the meantime, Linda flew to Germany on a commercial flight. On Thursday morning, Pacific time, we got an excited call from Linda in Germany, informing us that Uli had arrived safely. She asked us to call back right away, because she was using a pay telephone and had run out of change. We called back and talked to both Uli and Linda. What excitement and what a relief! We really had no reservations about this airplane—only a question of whether the Lycoming would keep running and, of course, the weather. But we knew Uli was a superb pilot and would get through one way or another.

Uli said he has some fabulous pictures of his trip, and has promised to write his account of his crossing for one of the US flying magazines. Uli and Linda will have their hands full for awhile, because they have purchased a home which was unfinished, and it will put their building skills to a real test. They have already organized Co-Z Development, Europe, and started going to European fly-ins. At one, in Switzerland, they received a trophy for coming the greatest distance—it is hard to beat Texas to Germany! They must have impressed a few people, at least, because they sold 2 sets of plans on the spot. We have become close friends, and promised to visit them in Europe in 1987 (and as many other Cozy builders as possible).


Since this summer marked the first year anniversary of our move to Arizona, we planned to leave early on our trip to Oshkosh and stop off in Minnesota to visit children, grandchildren and friends. My sister, Lee Parlee, came down for IL to tend our house and office while we were away. Some of you may have received one of the nice long letters she wrote to all of those who had questions while we were away.

We planned to depart Mesa on Monday, July 21, but it was "monsoon" time of year in AZ, and the Mogollon Rim country, over which we must fly to get out of here, was socked in. So we delayed a day, got an early start, and sneaked over the high country before the build-ups were very threatening. We made potty stops (and fuel) in Tucumcari and Grand Island. We had tail winds most of the way and averaged about 200 mph to South St. Paul, arriving there about 5PM, after a 2 hr. time change.

We visited friends and relatives in the Twin Cities for several days, and then flew down to Rochester to spend a few days with our son and his family. On Monday, July 28th, we flew over to Oshkosh. There were hardly any other airplanes there when we arrived, but a lot of campers. It had rained a lot the day before, and it took full throttle to taxi across the wet sod. We staked out space on the flight line near the main gate for several other Cozys, and then went on to our campsite in Paul's Woods, where we roped off enough space for a whole bunch of Cozy campers. For the next several days, we divided our time between defending space on the flight line and defending space in the campground.

We don't remember for sure, but we think Jack and Donna Wilhelmson, and Ken Francis and Vance Atkinson both arrived in their Cozys on the same day, Thursday. Jack and Donna nonstop from SC and Ken and Vance nonstop from TX. We could hardly believe our eyes. We didn't think anyone could equal Uli and Linda, but here were two more Cozys that looked like they came from the same mold. They were so close to equal, how could we ever decide who would win the trophy for the best Cozy? I wished I had had 2 trophies so I could have awarded one to each, but that was not the case. At the Cozy forum on Saturday, I asked help from the Cozy builders who were present. We got 33 builders to carefully inspect both Cozys, and to vote on their choice. We kept the ballots unopened for several days until they were all in.

At the forum, we had Jack and Donna speak, Ken Francis, and Merle Musson. Merle and Lucy Ackley also flew in in their Cozy, but parked in the airplane-camping area. We also invited Ken Winter to talk about the 4-place Cozy that Aeromet is building. He gave an interesting account of the high-tech surveillance work they are so deeply engaged in. We had a good turnout (the tent was full) of builders and prospective builders at the forum, and had a good time.

We had 3 Cozys parked in a circle on the flight line and there was a lot of interest. We ran out of plans and Info kits on the 3rd day, and Wicks wanted to know why we didn't bring more. Everyone wanted to sit in the plans built Cozys, but Jack and Ken were fussy, so everyone ended up climbing into the prototype (as in past years), and we had to keep explaining that ours was smaller.

We had many interesting experiences. One young lad, who looked barely out of high school, spent a lot of time looking and asking questions. Finally, Shirley asked him if he had pilot's license, and he said he flew for Federal Express, in a 727! A couple of weeks later, he showed up at our house in Mesa to purchase plans.

The airshows were, as always, spectacular. The hit this year was the Italian acrobatic team, flying 10 jets in such close formation their wings were actually interlocked. You just couldn't believe what you were seeing.

On Tuesday we counted the ballots. It was 17-1/2 for Jack and 16-1/2 for ken, but it really could have gone either way. We didn't want either to lose. Lon Cooper came through for us again this year with another beautiful trophy. It was an exact scale model of the Cozy, on a swivel, on a beautiful pedestal made of a slab of transparent acrylic mounted on a walnut base. The inscription read "Best Cozy, Oshkosh 86, N711CZ, Jack and Donna Wilhelmson". The trophy was presented to them on Thursday evening, in the Theater in the Woods, during the designer awards ceremony. It was our way of expressing our appreciation for a beautiful rendition of the Cozy design.

On the way back from Oshkosh we again stopped at the Twin Cities for more visiting, and then at Albuquerque. Then back over the Mogollon Rim country to Mesa. We were blessed with beautiful VFR weather for the entire trip and one sweet flying comfortable airplane. Back home again we found that Lee had been doing a terrific job of keeping our business running, and taking care of the house and yard, and we had a few good days of visiting before we had to say good-bye and put her on the plane for home. She liked Arizona and offered to pinch hit for us again next year.


We didn't make it to Kerrville again this year, but Ken Francis did. He reported a lot of interest in the Cozy, and he received the recognition he deserved—the award for Reserve Grand Champion. We think he would have bean awarded Grand Champion, except Uli and Linda were awarded that last year they didn't want to select 2 Cozys 2 years in a row. Congratulations Ken!


Ever since my bad experience with the BD-5, I have always looked for an engine before starting to build an airplane. So I have been looking for an engine for the Mark TV. I have learned that many builders don't believe the designer, when he says a certain size engine is optimum for a particular design, and so they put in the next larger size. So I decided this time to get one leg up on the builders. I would design for the O-320, but put in an O-360. Smart thinking, wouldn't you say? In my looking, I came upon an entire airplane for sale with a 1000 hr. O-360. It was a BD-4 (4-place homebuilt) being sold on the condition that it not be flown (liability), but dismantled for parts. It had been advertised for a long time, with no buyers willing to agree to the terms, until I came along. In the meantime the price had been dropped gradually but steadily from $10,000 to $4,000. I didn't really want to use the engine in the Mark IV, because it was an IO-360 of 200 hp, and 25 lbs heavier than the O-360 I was looking for. But the airplane had a Hartzell constant speed prop of 50 hrs TT and, I figured, at least $3,000 worth of useable instruments and parts. I bought the airplane. Shirley thought I was crazy. I advertised the engine and prop, and sold it for a little more than what it cost me to buy a remanufactured O-360 exactly to my specs. With a little luck in disposing of the airframe (know anyone who wants a BD-4 airframe cheap?), I will end up with my engine costing next to nothing. I have heard of other people getting engines for little or nothing but this was my first experience. I wouldn't know how to advise others, except to start looking early, ask a lot of people, see what happens, and don't be afraid to take a chance.

The Aeromet 4-place is way behind schedule. Originally it was scheduled to fly before Oshkosh. It is almost completed, except for the engine. But I don't know when it will fly. Aeromet is involved in so many different projects that some occasionally have to be put on a side burner. Apparently that is what happened to their Mark IV.

In the meantime, work on our Mark IV is proceeding apace, in between interruptions for newsletters, telephone calls, drop in visitors, etc. The fuselage tub is complete and glassed on the outside. The centersection spar is complete, but not installed. We're getting ready to install the shoulder support and headrests, and the main gear. So far, the changes we planned are all working out well.


The following news clippings caught my attention:

  1. Osprey - I have been flying my Osprey on auto gas for over a year now with no problems, but I have finally found a good reason not to use it. TOLUENE! Toluene is a very strong flammable solvent, and apparently some oil companies feel mixing it with gasoline is OK. That's fine for metal gas tanks, but not fiberglass and resin. It was dissolving my tank. I had noticed that it was hard to see the fuel level lately in the sight slots, and I found some brown globs when I was checking the sump. Well, the side walls of my tank are soft and I am debating replacing it with a metal tank. I think I'll pay the extra fifty cents a gallon for Avgas, because there is no telling what they will put in there next. EAA Technical Counselor News, Jan. 1986
  2. Varieze - After 5 plus years of flying his Varieze, Gary plans to bring it home, give it a facelift, and overhaul and replace the gas tanks. "I have the feeling they are getting mushy" writes Gary. "A friend of ours found this to be the case with his Eze which is also about 5 years old. We both used the old type epoxy and have used auto gas. We feel the combination of the first type epoxy and auto gas has caused this condition". Gary suggests other Eze flyers might want to check their tanks for this condition. Central States Newsletter, March 1986
  3. Piper PA-18-150 Tri-Pacer - The engine lost oil pressure, then power, resulting in a crash landing. Later investigation revealed that a hole had burned into the top and side of one of the pistons. This resulted in internal damage from metal contamination. The use of automobile fuel had been approved and was being used. Aero, September 1986


In the last newsletter (NL #14), we reported on the only known case of an in-flight engine fire in a Long EZ, which unfortunately resulted in a fatality. We reported this accident because the Cozy is very similar in design and performance to the Long EZ, and our stated purpose was to try to learn how to prevent such accidents.

There is little doubt that the accident was caused by the use of auto fuel, which is prohibited in both the Long EZ and the Cozy (see Owners Manual). A study of the properties of auto fuel (volatility and auto-ignition temperature) should convince most people that it is much more hazardous to use in an aircraft than Avgas. History seems to bear this out because leaks of Avgas have occurred in the past without resulting in fire.

A contributing cause of the fatality was the failure of the pilot to land immediately. He passed over a clear grass field in his attempt to make it back to the airport, but went down in a housing development when his engine stopped.

Our conclusions as to how to prevent accidents of this nature are:

  2. Make sure your fuel system is correctly installed using AN fittings and that it is fail safe, that is, gascolator drain and bale safety wired, fuel pump diaphragm vent piped overboard, fuel pressure sender mounted on firewall via armoured hose, etc.
  3. In the rare event of a fuel leak and/or fire, shut off the fuel and land immediately.

Incidentally, the cause of the fuel leak in this accident may never be known for sure, but the best guess of one of the investigators was carburetor flooding due to disintegration of the carburetor float, presumed from the auto gas.

The July 86 Canard Pusher reported on the same accident. It noted that auto fuel was being used, which probably caused the fire. It also cited several examples of in-flight Avgas leaks which did not result in fires. However, instead of taking this opportunity to emphasize that use of auto fuel is prohibited, RAF recommended fireproofing the firewall and control system components passing through the engine compartment. The logic escapes us. We immediately received many calls asking if we were going to make the same mandatory design changes.

Although RAF's mandatory changes would not have prevented this fatality (or any other that we know of), we think that painting the firewall with a new, high-temperature insulating coating which has just become available from Wicks, namely Ocean #1644 Intumescent, is a very good idea, and we will recommend it also. At the Wicks booth in Oshkosh, we saw a sample firewall panel which had been "torch tested". The protection afforded by the intumescent coating was very impressive. If you paint this material on your firewall and surrounding structure, you will be buying a lot of protection for a small amount of money and effort. As for replacing all aluminum parts of the control system in the engine compartment with steel, we do not believe this would be worthwhile. The airflow through the cowling is away from the firewall, through the engine, and out. Although experience is limited to one accident, the pilot had full control of the aircraft to touchdown. It was only after the aircraft was consumed by fire on the ground (with no airflow through the cowling) that the control system was destroyed.

Lastly, how would you know if you have a fuel leak or an engine fire? If you are using Avgas, your only indication of a fuel leak might be a drop in cylinder head temperature as the evaporating fuel supplies additional cooling of the cylinders. If you are using auto fuel, you will certainly have an engine fire, which will be indicated by a rapid rise in cylinder head temperature, accompanied by smoke and blistering of paint on the cowling (which should be visible from the cockpit), and eventual stoppage of the engine. At the first indication of fire, you should shut off the fuel valve and execute an emergency landing. If you have a significant drop in CHT, you should land at the first opportunity and investigate.

We hope that we haven't belabored this subject, but when we take exception to a recommendation by RAF, we think we owe you an explanation.


  1. There are a number of places in the plans which call for sanding a 1/16" depression in the foam to allow for a future overlap in the fiberglass layers without causing a bump which is difficult to hide in the finishing process (for example, around the landing brake). A router attachment for your dremel would be very useful. We didn't have one, so we improvised by making a fixture out of a wood block, adjusted the sanding drum on the dremel to make a 1/16" cut, and were able to make very nice, uniform depressions.
  2. Shaping the outside corners of the fuselage can be quite a chore. We found the best way so far is to put a long blade in your sabre saw, set the saw for a 45º angle, and cut away the foam and glass just down to the longeron. Then use a belt sander with a coarse belt to round the corners per the corner template shown in the plans. The template for the outside bottom corners assumes very thin joints, where the foam attaches to the longerons. If you have thicker joints, you will have to increase the radius of curvature of the template to have a smooth curve which is tangent to the side and bottom and exposes 1/4" of the longeron, as instructed in the plans.
  3. The plans show the fuselage supported on A frames for glassing the outside (Chapter 7, page 2, Fig.8), so it can be easily turned. Drill a 1/4" hole through the frame and firewall on one end and the frame and F-22 on the other end (or NG 31 if the nose is installed), and put in a 1/4" bolt so the fuselage will have a pivot to rotate about. It is so convenient to work inside the fuselage when it is on pivots, do as much of the inside work as possible before permanently installing the landing gear and centersection spar.
  4. You will make better layups and have fewer problems with air if you apply a liberal amount of epoxy to a surface (or previous layer of glass) before laying down the new cloth. The new glass cloth will wet out from underneath, driving the air ahead of it, requiring less squeegeeing. If you use this technique, squeegee all excess epoxy out of the previous layers first, then apply fresh epoxy. Otherwise you may have an epoxy build-up between layers and end up with heavy layups.
  5. If you have trouble laying glass into a corner or around a corner without creating an air bubble, try putting a piece of saran wrap over the trouble area, and then working the air out with your finger. Once the air is out, the saran prevents it from returning. Remove the saran after cure.


We have not yet installed a Loran in out prototype N22CZ (we have an RNav), but we plan to put one in the Mark IV. We were confused about where would be the best antenna location because there are so many diverse reports. The consensus seems to be that locating it in a winglet has some disadvantages.

For one thing, it is recommended to string copper wires in the wing cores before glassing for a ground plane. Secondly, we have heard many complaints that in turning maneuvers, the Loran will have fits because the wing tip can change speed so quickly. Mike Melvill strongly recommends locating the antenna on the centerline of the airplane. He installed a ground plane on the bottom of his Long EZ and hung a whip antenna underneath the belly. He says it works great. The only problem is that it is really sickening to a purist to see antennas sticking out of otherwise clean plastic airplanes. So we got on the telephone and called up friend Jim Weir, of Radio Systems Technology. We have used Jim's home made antennas in several previous airplanes, burying them in the fiberglass where they can't be seen, and they work great, and the price is right. Jim said the best hidden location would be to run a small wire down one of the gear legs, inside of soda straws or Nylaflow tubing, so the wire wouldn't break when the gear flexes. Put the amplifier in the compartment behind the back seat, and use the aircraft ground, connected to both the battery and engine, as the ground plane. If you really want to be fancy, ground one of the control stick torque tubes as well, which would then pick up the elevator torque tubes in the canard, the torque tubes down both sides of the fuselage, and the aileron torque tubes. He says not to worry about antenna length—just make it as long as you can without getting too close to the wheel, calipers and discs. Sounds great, and we have a lot of faith in Jim so we are going to give it a try.

In the course of our conversation, Jim asked me if I had purchased a Loran yet. He suggested that I consider the Apollo. He is vary pleased with his, and he is an Apollo distributor, he said he would be willing to give me, and any other Cozy builder, a very good deal—just a small markup over his cost. Sounds interesting!


With the Loran antenna location solved by putting it down a gear leg, none of the other antenna locations in our prototype would be affected. They are all excellent locations. To review:

Amazing! All these antennas and none are visible!



Thanksgivings - Let's all count our blessings. We thank Burt for allowing us to use the Long EZ design in the Cozy, and that as a result, it is such a nice airplane. We are also thankful for all of our wonderful builders, and hope that you have many things to be thankful for too!

Christmas - We expect to be away over the holidays and wish to take this opportunity to wish all of you a very MERRY CHRISTMAS AND HAPPY NEW YEAR!


Dear Nat,

Enclosed is $230 for Cozy plans, $15 for the Owners Manual and $5 to start the newsletters.
I have been working as a mechanic and inspector for the past 20 years of which 7 were spent at Oshkosh. I have seen a lot of airplanes, both homebuilts and factory builts, and none of these have impressed me as much as the Cozy.
This is going to be a long-term family project, hopefully starting this winter and for the next couple of winters. Keep up the good work!

Thank you,
Gary L. Riedel

Dear Nat,

I am nearly finished painting! Tomorrow it's the wings and then I only have the stripes left to do. 1525 hours building time so far, since Jan 1, 1985. The final finishing and painting was a lot harder than I expected. I had to work hard these past few weeks so I could get it painted before it snows here.
My airplane is base white gloss with Royal Blue metallic stripes on the fuselage and arm rests with silver blue metallic interior. I used the Ditzler system with Morton's Eliminator underneath, and Preet-33 in between. My paint area has some dust problems, so there are same particle lumps in the paint. I suspect they will rub out when I wax it.
I read that you grew up in Fond du Lac, WI. I was born there in 1950. My home is in Lomira, WI, 12 miles south. My folks still live there. I still haven't made it to Oshkosh. I hope to fly my Cozy there next year.

Thank you,
Jack Grandman

Dear Nat and Shirley,

Just a quick note to tell you how much I enjoyed seeing you and visiting with all the Cozy people at Oshkosh this year. My only regrets are that I was not able to make it in my own Cozy or that my twin brother Bob was not able to come in his beautiful Long EZ because of his accident last July. I would like to thank all of those who showed their sincere concern for Bob's recovery. He is in Baylor Medical Center's Rehabilitation program in Dallas and should be out by November. It will be a long road but he'll make it and get back to flying Falcon 50's again.
I cannot comment on the ultimate causes of his engine failure and resulting encounter with power lines during an otherwise perfect approach to an emergency field. His canard may have obstructed his final view of additional small lines above the primary line that he did see.
I am concentrating on the finishing process of my Cozy and I hope to have the fuselage primed before cold weather sets in here in Colorado. Progress has been slow this second year with our move, our first baby (Chandelle) and Bob's accident. But we will make Oshkosh 87!

Al Yarmey


Uli Wolter in Cozy N52CZ over the water - Photo by Carl Schuppel

WHICH WAY'S UP? -- Spectators hovered around an unusual looking three-seat experimental aircraft called the Cozy at the Experimental Aircraft Association's annual fly-in in Oshkosh. The plane seats two people side-by-side and one person behind.

This newsletter transcribed to HTML by Gene Traas.