[Cozy MKIV Information]
COZY NEWSLETTER #50
Table Of Contents
When I looked at their engine installation in the morning, it was pretty obvious what was wrong. The builder hadn't baffled the fins at the underneath side of the cylinders. This meant that the air was not forced to go between the fins. When I pointed this out, he said that other builders in California told him that this wasn't necessary. The second problem was that he had left gaping holes around his exhaust pipes, which meant that most of the cooling air was escaping out the cowling around the pipes without having to go through the cylinder fins. In effect, there was very little pressure difference to force the air through the fins. I explained that if the engine is correctly baffled and the high pressure side of the cowling is sealed, his engine should run cooler than any factory built, and it would not be n to cut holes in the top of the cowling over cylinders #1 & #2, as he was planning to do.
From Ft. Stockton we flew VFR over the top for about an hour, and then it was clear the rest of the way to Florida. It was now Monday, and our reservations in Lakeland didn't start until Saturday. We had heard about a nice resort in the Orlando area, so we headed for Kissimmee and pulled in there around 6 PM. We were able to get a room without advance reservations. We moved the airplane over to Lakeland under a 1000 ft. overcast on Wednesday, rented a car and went back to our resort until Saturday. We had a very good time and enjoyed our unplanned vacation.
On Saturday we joined the Wilhelmsons and the Vargases and stayed together at a condo in Imperial Lakes. The fly-in started on Sunday. We think that there were 13 Cozys altogether. It was a little hard to keep track, because some were parked in the camping area, and others kept coming and going. This was a pretty good turn out since the frontal system we beat stalled out along the east coast and kept some Cozys from making it.
Sunday night was the annual Cozy banquet at the Red Barn. This time they reserved a room for us (as promised). We had about 50 or so, and everyone had a chance to talk and appeared to have a good time. As has become our custom, we picked up a crate of strawberries ($5) at a roadside stand to take back to the condo. It was good to again see a lot of builders we see only once a year.
Jack and I had a chance to look at and critique 3 different retractable gear: The Infinity, which folds inboard, and the Velocity and Berkut, which fold outboard. Incidently, the Berkut had repairs in progress on the bottom of the fuselage, apparently the result of the gear being unintentionally retracted (or collapsing). The Infinity gear appeared to be the heaviest. It had a large electric hydraulic pump in the nose to offset the weight in the rear, and required the largest cutout in the strake. We speculated that weakening the strake and putting more torsional loads on the center might cause flexing and leaks, in the fuel tank area over time. The Velocity and Berkut gear pivot inside the fuselage and require cutting into the fuselage side as well as the strake. It was unclear how much fuel capacity was sacrificed in each of these cases. Jack and I agreed that there is no way a retractable gear could be as strong in torsion or other stress modes as the single glass strut with its attach points 26" apart.
Vance Atkinson was there with his new, electric nose lift installed. He demoed it for us. Vance is young (relatively), healthy, and strong, and I really didn't understand why he would need an electric lift in the nose of his Cozy-that is until I tried to lift it myself It must have been over 100 lbs., and I absolutely could not lift it myself I have never put the nose of my airplane on a scale, but I would guess its only about 25 lbs., which gets lighter as you raise it. Vance explained that the reason his airplane is so heavy on the nose is that he accidently mounted the main wheels 1" further back than the plans call for. He said this is one step in construction where it pays to be accurate!
The weather was good all week, and there was much interest in the Mark IV. Approximately 40 people climbed in and out of our airplane before the week was over. Todd Morgan was awarded the "Best Composite" at Sun `n Fun for his Cozy. Congratulations again, Todd!
We made it all the way back from Lakeland to Mesa on Friday. The last half of the trip we had 35 knot headwinds and severe turbulence, which made the trip seem longer than usual.
A week or two after Sun `n Fun we were saddened to hear that our accountant, close friend, and Cozy builder Herb Peterson died of natural causes in Albuquerque. We went to the memorial service and offered to help his widow, Jane, find a buyer for his project and all his shop tools. We brought the project back to Mesa where a new builder, Dr. Douglas Ashby, agreed to take it over. We have the project in our shop temporarily helping Doug get up to speed. In between trips we keep pretty busy showing visitors our airplane and taking them on demo flights.
Antenna Reference Text RST-802 $5.00 100' roll of copper tape RST-2800 $20.00 Bag of 20 toroids RST-2801 $7.50 Their address is: 16214 Jacks Rd., Nevada City CA 95959 Phone: (916) 272-2203 or (916) 478-0641.If you get a recording, leave your evening phone number because they return all calls each evening. If you prefer to purchase antennas pre-made, contact: Bob Archer, Sport Craft Antennas (310) 316-8796.
If the NACA scoop underneath the fuselage is built according to plans, baffles are added in the lower cowling according to plans, and the engine itself is baffled according to plans, there will be no cooling problem! Our plans model is living proof of that! As a matter of fact, cylinder head temps should run low, in the 290 to 350 deg. F range. Even on the ground, convective cooling keeps cylinder head temps low, and certainly less than factory - builts with down-draft cooling. Furthermore, built as designed there will be ram-air induction into the carburetor (which boosts engine power) and cooling of the accessory case (to avoid cooking the magnetos). If built according to plans, there should be no need to install exit air vents over cylinders 3 and 4. We have not investigated ram armpit cooling scoops (underneath the strakes) because there has been no need to. We do know that the engine baffling would have to be revised, that they wouldn't be as effective in cooling on the ground, and wouldn't provide ram air for the carburetor or convective cooling for the accessory case. We suspect they would increase drag, which was the reason NACA scoops were developed in the first place, to eliminate the drag caused by ram scoops. In short, revising the cooling system by eliminating the NACA scoop and installing ram armpit scoops would be a step backward. Burt Rutan's advice to first time builders was to first build according to plans (which were thoroughly proven), and then make any changes they might want to try. That would be the only way they would ever know whether the change was an improvement, or whether they should go back to the way it was.
Another case in point is the fuel system. The design should not be changed! Two separate tanks are provided so you will have a redundant fuel supply. If you have a leak in one tank (it has happened), you can safely operate off the other until you have an opportunity to repair the leak. If you have contaminated fuel in one tank (it has happened) you can operate off the other tank without risk of damaging your engine. If you have water in one tank (it has happened), you can switch tanks to keep your engine running. As a matter of fact, if your engine ever coughs or hesitates, you should automatically switch tanks. You can extend your range by running one tank dry and then switching to the other tank to more accurately monitor fuel remaining. The plans show sumps located outside the fuselage, to eliminate any fuel inside the fuselage structure, where it might leak and create a fire hazard. You should not install a sump inside the fuselage and connect the tanks together!
If you connect your tanks together and ever lose a fuel cap (it has happened), you would have a vacuum in that tank and pressure in the other, and you would lose all of your fuel out the open tank. Also, you should not locate the fuel valve on the firewall, or anywhere you cannot get your hand directly on the handle. Experience with the Varieze many years ago, where the fuel valve was located on the firewall, demonstrated that a sticky fuel valve could not be operated as well on the end or a torque tube (or cable) as with a hand directly on the handle, and a number of emergency landings were attributed to this cause. That is the reason the fuel valve was located in the front cockpit on the Long EZ. Locating it in the seat-back on the Cozy was considered to be a further improvement, because it shortened and simplified the plumbing, but still allowed hand operation. The fuel system shown m the plans was designed to eliminate any conceivable problem in the fuel supply which might cause an emergency landing.
We have been as conscientious and diligent as possible in trying to provide the safest and most reliable design for our builders, and it really hurts when we hear of a first time builder making design changes which he thinks is an improvement but we know may endanger his safety or cause him problems down the line. Even though these are "experimental" airplanes, we firmly believe in the adage, `If it ain't broke, don't fix it!'
Along a slightly different vein, we are occasionally asked about substitute materials. Some suppliers are pushing triax glass cloth and alternate epoxy resins. Our position is this: As a licensee of Rutan Aircraft Factory, and one who respects Burt Rutan's thoroughness and judgement, we are very reluctant to approve materials which he has not first approved. The triax cloth might be quite strong in the 3 different directions its fibers are oriented, but it does not exactly duplicate the fiber orientation specified in our plans and in the Long EZ plans, which has been well tested and proven over a long time. One of our boulders who tried using triax cloth found it to be stiff and hard to confirm to compound curves, and when he tried to squeegee it, developed wrinkles in one or more layers. He ended up having to remove the triax from a large area on the wing and patch it. When he was finally done, he had caused himself more work, wasn't as well satisfied with the quality, and wished he had followed the plans.
We don't see any reason to evaluate and approve other epoxy resins. It was necessary to get Hexcel to reformulate Safe-t-Poxy, to eliminate the MDA that OSHA objected to. But that has been accomplished and we have a good resin now, Epolite 2427, and see no reason at present to consider further changes. We would like to have all Cozys built from the same materials of construction, in so far as is possible. It is just too hard to control quality when too many substitutions are made. There are some design changes, like internal rudder belhorns, retractable steps, etc., which don't affect safety or aerodynamics, and may not greatly affect weight, but which take longer to do, and for that reason we don't show them in our plans. We try to show the simplest way of doing any particular job. But if individual builders wish spend more time building and be more sophisticated, we have no objection.
Dear Nat & Shirley,
My Mark IV will be under construction by mid-summer, now that my A&P schooling is finished. My A&P license was obtained via the North Valley Occupational Center of the Los Angeles Unified School District (LAUSD). The school is at Van Nuys airport and the best deal ever heard of. It may be of interest to other Cozy builders to make some bucks working on other people's planes.
Most private A&P schools charge about $15,000 a year tuition, and it takes about two years of full time schooling to get the airframe and powerplant license. That's $30,000. But, take the same courses in the tax-supported LAUSD and the total cost to get a license is less than $500(!), spread out at only $55 per semester. You can go full time, part time, or all day, evenings and Saturdays. Either way, fast or slow, the cost is the same. This is one of the best kept aviation education "secrets" of all time.
Private schools advertise all the time, and are full of students. LAUSD practically never advertises, so classes are small. For more info, call (818) 785-7511.
Hope to make it to Oshkosh this year in my Cozy-3, or possibly drop in
to say hello to you and Shirley sometime. Wishing you both the best of
health and good fortune.
Woodland Hills CA
May 23, 1995
Enclosed is the newspaper article about 62 year old Bill Davenport's crash of his Long EZ just off the Santa Monica Airport. The facts are these:
Fortunately, he lived to tell the tale, this time. His injuries were amazingly slight. No broken bones and probably no permanent disability. The plane (a Long EZ) was totaled.
I would only stress that Bill's recklessness is just another nail in the coffin for Santa Monica Airport. There is strong opposition to keeping it open. In every accident report, the press always reprints the list of previous accidents.
It might be in order to remind your builders: (1) Don't mess with the fuel system, and (2) behave responsibly, with the understanding that flying "rights" are actually only priviledges on loan to us.
This accident was no accident!
Dear Nat & Shirley,
My husband, Dan Dahl, and I were delighted to meet you at Oshkosh last summer when we flew there in our Long EZ for our first time at Oshkosh. As you may remember, in addition to buying our Long EZ, we had purchased Richard Bienvenu's partially built Cozy and were beginning that wonderful adventure of building our own plane.
My husband, Dan and my thirteen year old daughter, Sarah Frydman, were killed in the crash of our Long EZ on February 1, 1995. I have enclosed an explanation that I put together for family and friends which you are free to edit in any way for your newsletter. I know that EZ and Cozy pilots always want to know about the circumstances of any crash, so that we can avoid them in the future, and keep our remarkable airplanes as safe as possible.
I have two requests. First, please change your mailing address to me at our home: Jessica Dahl, 155 Preston Oaks Dr., Alpharetta, GA 30202, phone (404) 740-0606.
My second request is to all Cozy builders. It is the intention of my
stepson, Eric Dahl, and myself to finish building our Cozy. I have just
begun flying lessons, I'm on my second one, and loving every minute of
it, and hope to be a pilot by the end of the summer. Eric will also
begin training, possibly during his stay with me this summer. However,
we need all the help we can get as we attempt to do this without the
leadership and direction of my beloved husband. We are currently
working on the first layer of micro, and I would love any advice on this
process, and on how to put together the avionics for our plane. Also, I
would welcome a visit from any and all Cozy owners when they are in the
Atlanta area for a little moral support and encouragement. I fell in
love with our Long EZ and liked nothing better than to be flying with my
husband, and this accident has only reinforced my love of this
remarkable act my husband, my daughter, my stepson, and I shared. So if
you could get the word out that we need help, I would greatly appreciate
it. My stepson and I hope to be at Oshkosh this summer again, and look
forward to seeing you all there. Dan and I simply loved you both when
we met you. You have a down-home warmth that simply envelops all who
meet you, and you have that love of flying we share. If you are ever
in the area, I would be honored to have you as guests in my home. Thank
you all for your support and encouragement.
Editor.- The account of the accident Jessica sent us is too long to publish here. In summary, Dan was an ex Top Gun instructor and an excellent pilot. He was helping his stepdaughter, Sarah, with a science project involwng the Long EZ. They were measuring acceleration on the runway prior to rotation at different gross weights. The study did not involve flying. For some unknown reason, the Long did not slow down after the high speed taxi run, as expected, but continued at full power the entire 5,100 ft. runway and crashed into a ravine beyond the end of the runway. It is Jessica's firm belief that Dan suffered some physical impairment like a stroke, and that Sarah was unable to close the throttle or ignition switch from the back seat.
March 6, 1995
Dear Nat and Shirley,
Mark IV #218 is coming along fine. Finally got the shop insulated and heated. Started the canard & elevators in February and am glad to say they are very close to being done. EAA chap.,#463 asked to have their meeting at our house to see composite construction in progress. We had 28 people in attendance and all quite interested in how strong the fiberglass foam combination was. I was asked a couple of times if the fuselage was pre-fab. I almost took offense, but then realized that your plans are so good, the product just naturally has to look good. I received my electrical switch/breaker panel from Wayne Lanza and have to complement Wayne on a beautiful job, very professionally built and I would highly recommend builders to contact Wayne and purchase this fantastic component. I liked the panel so well, I ordered the electric speed brake actuator also and it's a great little item also. Looking forward to seeing you at Oshkosh in July. We will be at the 5th gathering of canard aircraft in Oklahoma City in June. Thanks for great plans and a warm Cozy family of builders and friends.
Kip & Donna Davis
Dear Nat & Shirley,
It has been over a year since I talked to you. That statement alone is a compliment to your plans as I have progressed through chap. 13 and halfway into chap. 14 and have no questions about any of your very thorough plans and instructions. On a recent business trip to NC, I took the time to visit Aerocad. Jeff was very busy trying to finish his new airplane for Oshkosh, but he took almost half a day showing me various tips and time savers. This morning I sent him an order for the spars and the fuselage top as well as some other pre-fab pieces. I figure I may save almost a year in construction time. Jeff, his dad, and the other employees were super nice people and a great asset to the homebuilder movement. Nat, I am finally going to make it to Oshkosh this summer to meet you and Shirley and to see your airplane. It will be the first time to see a completed Mark IV. My dad is coming with me and is excited too.The last time I talked with you, your suggestion to me was either I lose some weight (330 lbs.) or my bird would be a single seater in front. I am happy to report I have lost over 90 lbs. (.738 lbs.) and within a few more weeks will weigh 225 lbs. which is my ideal weight for my 6'3" frame. Didn't really go on any diet. Just started exercising and took most of the fat grams out of my diet. It was EZ!
Thanks, Gary Dwinal
March 23, 1995
Just wanted to give you an update on our progress. We've been able to complete the fuselage through chap. 8. My weight at that point was 92 lbs. That seems to be about 12 lbs. higher than your published weight. I ordered the landing gear and canard, and while waiting to receive them, we've managed to complete the landing brake installation.
May 18, 1995
I have come across some good companies that offer great products that are helping my building process, and I recommend them to other builders:
(1) Highland Hardware (800) 241-6748 offers a Dustfoe 66 industrial dust mask for $25. This mask is light, comfortable, and effective. I use it for all my sanding operations.
(2) Klingspor's Sanding Catalog (800) 228-0000 is devoted to really good sanding stuff. Their products cut real fast and last much longer.
(3) Woodsmith Shop Catalog (800) 444-7002 has unique clamps, tools, shop accessories, etc.
(4) Featherlite (our authorized supplier) does good work, despite the appearance of their price list. Ask about lead times (i.e., main landing gear).
Regarding my query about alternate fuel valve locations, you will
be pleased to learn that the fuel bracket has been fabricated (after 3
attempts) and is now installed per plans. Thank you for your input.
Aliso Viejo, CA
Editor.- I must put in a good word for the 3M Co, my employer of 30 years. They make a complete line of the highest quality sandpaper, including wet or dry, from 36 to 2000 grit, and buffing and glazing products to go beyond that, inexpensive dust masks, every kind of tape imaginable (including the copper tape for antennas), glass microspheres, weather-stripping, and many other products we use in building airplanes.
March 3, 1995
Here are my MKIV unfinished weights as of today:
Center section spar 48 lbs. Fuselage on gear (no canopy or strakes)* 242 lbs. Canard & elevators 33 lbs. R. wing w winglet & aileron 69 lbs. L. wing w winglet & aileron 68 lbs. Turtle deck w glass 12 lbs. -------- Total to date 472 lbs.Includes seats, arm rests installed, control system, nose complete, brakes, but no canopy or strakes. It's been much too cold to work the last 6 weeks, but will be back at it as soon as spring appears. Should be to "finish" stage later this year. Hope you are well.
June 3, 1995
Can a year already be PAU (Hawaiian for `finished') on my subscription? It seems like just a couple of months ago that we got the plans! Anyway, please renew my subscription so I can keep up with any changes you have to report. I haven't started working on my Cozy IV yet, due to my computer dying and trying to save up to buy a house. I hope that in the near future, my son and I will be involved in BUILDING, instead of just dreaming. I have seen Bill Denise's Cozy at the Kailua-Kona airport, and I was impressed. His workmanship really shows in his airplane. He has recently flown off his restricted hours, so he should be sending you an update or notice of completion pretty soon. Thanks for designing a great dream machine. Have a good summer. Take care, and God bless.
Just received another excellent newsletter, and need to send in my renewal. I thought this move to SD was going to be retirement, and plenty of time to finish the COZY, but guess I'm too easily distracted. Have enjoyed working with my brother on an operating ranch, and lately am getting involved in land surveying. A little supplemental income is helpful, but I'm still going to dedicate time toward completing the dream bird. The letters in your newsletter of the satisfaction of first flights is a real motivator. I pondered over adjustable rudder pedals, but didn't want to go to the expense or weight of the type in the Mark IV. So I made a 2" extension of both pedals from foam, with a brace extendmg down the shank, glassed overall, and cotterpinned to the shank to hold them in place.
After performing and paying for the maintenance on the landing gear of
my son's Mooney during the last annual, I certainly agree with your
perspective on retractable gear as stated in Newsletter #49. In fact,
I've shared that feeling all along, that retracts are neat, but they add
weight, cost, complexity, and risk of forgetting to lower them, and to
me the extra speed is not that critical. Keep up the good work and hope
to see you at Oshkosh