[Cozy MKIV Information]
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January, 1992

Table Of Contents

It's an old-fashioned custom
An old-fashioned greeting
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With every repeating
Merry Christmas & Happy New Year


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After sending out newsletter #35, we took a day off on Oct. 6 to fly up to the Copper State Fly-In at Prescott, AZ. It was a perfectly gorgeous day and we were pleased to find 4 other pristine Cozys parked on the flight line and to visit with their owners:

  • N84 CZ - Keith Spreuer (CA)
  • N 2 TM - Todd Morgan (CA)
  • N89 CZ - Mike Marshall (NM)
  • N32 HL - Jerry and Helen Lynch (MN)
We also met good friends and Cozy builders Ed Moulden, and Jim and Suzie Wickstrom, and Jim and Martine Allen. We had a good chance to visit with Ken and Marie Brock, and Jack and Golda Cox. We flew back to Mesa later in the afternoon, and I couldn't help but muse how wonderful it was to be flying along at 9,500' and 200 mph in an airplane we built almost 10 years ago. It took about 30 minutes to return from Prescott, compared to about 2 hours in a car. I can't understand why more people don't fly!

Last fall we made a basic decision that finishing the plans model Mark IV should be our top priority, and to concentrate on that before trying to publish Section II. There were some good reasons. First, we need to verify procedures and dimensions for the work in Section II, and also get more pictures. Secondly, we am having quite a few builders and prospective builders stopping in or asking to stop in to see the plans model Mark IV - In the meantime, if any of you complete everything in Section I and have run out of work and are chomping on the bit, send us pictures of your progress, and we will try to furnish you with xerox copies of additional chapters.

We took 10 days off, over Thanksgiving, to go back up to the cold country (and 3 ft. of snow) to visit our kids and grandkids. For the first time, we did not have someone in our house to answer the phone and mail. We were reluctant to explain on our answering machine that we would be gone so long. Instead we tried interrogating our answering machine from long distance each day and tried to answer as many of the calls as possible. If this inconvenienced anyone, we apologize. The plans model Mark IV is coming along quite well. The canard has been fitted to the fuselage and is in primer. The winglets are installed on the wings, the wings have been fitted to the centersection spar, the wings have been contoured with micro and are in primer. We have received all of the new parts from Ken Brock, except the canard torque tube offsets, but those should be available shortly. The fuselage is on the gear, all of the new nosegear parts are now installed, and we are very pleased with them. By way of reminder, the new parts can also be installed in the 3-place Cozy for anyone willing to make a few changes:

  1. MKNG-6 - A new pivot casting approx 3/4" wider than NG-6. It requires widening of the NG-30s locally by installing doublers on the outboard sides.

  2. MKNG-3 & 4 - These brackets are twice as thick in gage as the NG-3 & 4 to prevent them from bending in a hard landing.

  3. MKLST - Shock strut with heavy duty spring installed.

  4. MKNG-15A - Castoring nosewheel assembly (less wheel) for a 10" tire with a Davenport shimmey damper. The larger fork and tire requires a larger nosewheel wheel.

We have been sending quite a few parts off to Feather Lite, so that they can make molds and supply prefab parts. These are:

  1. The turtleback

  2. The nose cone

  3. The nosewheel wheel

  4. Front and back seat arm rests

  5. Landing brake mechanism cover

  6. Rear keel cover

  7. We haven't sent the cowling plugs yet because we want to make sure they fit the new fuselage after installing the engine. The remaining construction items to be completed on the Mark IV are the canopy and strakes. Feather Lite wants us to use one of their prefab Turtlebacks (copied from our plans-built) and also their strake kit, and we are awaiting receipt of the same. We made up one of the new exhaust systems for the Mark IV and discovered that it extends a little too low to fit in the cowling of the 3-place. We would like to modify it so that it fits both airplanes, so it looks like it will be a while longer before we can put this design into production.


At Oshkosh last summer we surveyed the various engine instruments which were available. We were particularly impressed with Electronics International instruments, which are based on digital technology. We decided to use them in the plans model Mark IV.

Their Programmable Ultimate Scanner is really an engine analyzer. It has two LED displays, one for EGTs and one for CHTS, and displays both simultaneously to a 1 deg. resolution, and scans up to eight cylinders. It has limits which can be set to assist or alert the pilot in managing engine operation. We will set ours up for 10 temperatures, i.e. 4 EGTS, 4 CHTS, I OAT, and 1 cowling exit air temperature. The latter will serve as our fire alarm.

Electronics International's tachometer is a real gem. RPM is displayed on an analog scale and digitally on an LED with a 10 RPM resolution. A red light appears if rated RPM is exceeded - It records engine hm cumumvely, starting when RPM reaches 1300, making a hobbs meter unnecessary. It also records flight time, starting when engine speed exceeds 2000 RPM and ending when it drops below 1200 rpm. Their Oil Pressure/Temp gage has analog scales with both high and low limit red lights as well as digital readout to 1 psig and 1 degree. Their Volt/Ammeter has a digital display with 0.1 volt and 0.1 amp resolution and a warning light to alert the pilot if the battery is discharging.

Electronics International appears to us to be state-of-the-art in engine instruments. Both Wicks and Aircraft Spruce carry these instruments.


The U.S. Aviator is a new aviation magazine published in Winter Haven FL (813) 294-6396, which has some very interesting articles and is rapidly gaining circulation and popularity. Its Managing Editor, Ken "Stealth" Cooke decided to build a Cozy Mark IV and called us to ask if we would mind if he published occasional articles about his experiences and progress in his magazine. Without knowing for sure what we might be getting into, we said we would be delighted. Ken has now published two articles and we are much relieved that he has not had any difficulty understanding the plans and instructions and appears to be enjoying the whole experience. He is a good and entertaining writer, and we have enjoyed reading his articles. We think you would as well, and encourage you to subscribe to this magazine and ask for the last two copies.


There are so many experimental aircraft filing IFR flight plans these days, it is difficult for controllers to be familiar with all of the different designs and their capabilities. The FAA, in cooperation with the EAA, is adopting a system of designators to be used in filing IFR flight plans. Under this system, similar types with similar performance will be grouped together under a common designator. Variezes, Long EZs, Cozys, and maybe even other designs will be in the same group. We suggested the this group be designated CZ-10, and this suggestion was accepted. This is a designator that should be easy for Cozy builders to remember, don't you think?


We thought there were more, but out notes show only one first flight in the last 3 months. Col. Ray Hart first flew on Oct. 5, 1991. His Cozy has a 150 hp 0-320 Lyc. He had 5 hours on it when he called, said everything was going very well, and promised to send us all the details and pictures.


The purpose of reporting incidents and/or accidents is to alert other builders to avoid a similar situation. Keith Spreuer wrote to us recently about a wheel fire:

Dear Nat,

My dad was flying on a trip to Colorado Springs in July with a friend. They just re-fueled in Gallup NM. The gross wt. was about 1520 lbs. It was about 100 deg. F and Gallup is 6469' MSL. This put the density alt. at just over 10,000' and the lift off ground speed at 88 KTAS (101 mph). There may have been a cross wind from the right which would have required left rudder application. We had just adjusted the brakes to increase the braking on the left pedal. If there was a cross wind this brake application would have slowed the acceleration. At any rate, my dad thought the acceleration was too slow and aborted the take- off, applying both brakes. The braking was not severe because the runway at Gallup is very long, but with the left brake already hot, a hot day, and a ground speed of 100 mph, hot brakes are to be expected. The heat generated radiated off the brake disc on to the tire. The gear leg did not overheat because it was protected by an 1/8" alum. heat shield. The heat, however, weakened the sidewall of the LAMB tire and it blew out. Once deflated, the tire contacted the hot disc and ignited. As soon as the tire blew, Dad stopped the airplane and got out. The fire started after they were out. They saw the fire and immediately got the fire extinguisher (which we carry on board) and put it out. By the time they got to it, the wheel pant and gear leg had burned and the NACA scoop was blistered. In another minute, the fuel tank directly over the tire would have been involved. The Gallup airport fire truck arrived about 10 minutes later. Needless to say, I feel a fire extinguisher is a mandatory piece of equipment. Ours was about 2 lbs. I think 3 lbs. is a minimum, since ours barely worked. There was no involvement of hydraulic fluid in this fire. This is because we installed a standard aircraft braided steel covered line from the caliper up the leg about 8". I also strongly recommend that. Inspection of the burned leg indicated that there was a ledge in one of the recesses where the caliper lobes nest into the gear leg. It appears that this ledge was caused by inadequate clearance for free caliper motion. Our wheel pants were not vented. I don't know if that would have avoided the problem or not, but my next set will be. The epoxy in the gear leg was burned out for the lowest 5" and the leg beat over until the tire contacted the upper leg. They cut off the lower 5" of the leg and brought it with the wheel and brakes home commercially. We had met Mike Melville a few weeks earlier and called to get his advice. He still had the steel splint that he used to ferry another Long EZ home with a crippled leg. We borrowed the splint and fit it to the piece we cut off our airplane. My dad and Morgan Dean flew back to Gallup and had it flyable in one day.

(Keith goes on to explain how they rebuilt the leg, making a mold and using S-glass rovings and epoxy resin. He reports the repair turned out very well, that their Cozy is back in service, and apparently no worse for wear.)


Several times in past newsletters we have warned builders about the possibility of damaging gear legs if the brakes are overheated and the gear legs are not protected by insulation and a reflector heat shield and the wheel pants vented. We would not have guessed that overheated brakes could also cause a tire to blow out and catch fire. We appreciate Keith's alerting us to this possibility. One of the most common causes of overheated brakes and resulting landing gear failure is dragging brakes; that is, calipers which jam and do not release from the brake disc when pressure is removed from the brake pedal. The caliper pins are designed to be a very loose fit in the torque plate, so they will not jam. This allows them to wobble, which is necessary for them to release properly. When fitting the calipers to the gear leg, it is not good enough just to be able to move the calipers in and out. They should be able to wobble in every direction without touching the gear leg. In fact, when the caliper is pushed hard toward the gear leg, there should stiu be a minimum of 0.1" clearance. Ignoring this requirement could well result in the type of incident Keith described.

Many builders, and in fact we, are nervous about cutting into the gear leg far enough to meet the requirement. It is our opinion, and that of others as well, that the calipers are over-designed and have more metal around the pins than is necessary for installation on a Cozy. We have therefore trimmed some metal away from the lobes on the calipers so we wouldn't have to cut as deeply into the gear leg to achieve the 0.1" clearance.

While on the subject of calipers, we should point out that the calipers not only move in and out when the brakes are applied, but they also move farther inboard as the brake pads wear. You should make sure there is also clearance inside of the wheel pants. Also, be aware that the heavy duty wheels and brakes, because the discs, pads, and calipers are thicker than on the standard wheels and brakes, require the wheel to be mounted farther out on the axle, specifically, the inboard bearing should be positioned 1.250" from the outer face of the flange. This will require a 7/16" spacer (or a 1/4" + 3/16") when using axles supplied by Brock, Wicks, or Aircraft Spruce.

This is a Cleveland specification. Do not believe anyone who tells you this isn't necessary!


Keith Spreuer us that the instructions for building the landing brake might be confusing to some builders. It is the procedure for both the 3-place and the Mark IV Cozy.

The cut out in Chap. 6 dimensions the recess in the bottom of the fuselage into which the landing brake retract. The cut out provides a 10" x .7" space in front of the brake to install the hard point LB-23 for mounting the hinge, so that the hinge pin will be 2-1/4" aft of the forward bottom edge of the ftont seat back. We thought it would be obvious that after filling up this l0" x .7" space with LB-23, it would be necessary to trim all or almost all of the 10" x .7" from the leading edge of the piece removed from the bottom before attaching it to the hinge, otherwise this piece (which becomes the brake) wouldn't fit into the recess. So we didn't specifically explain this, and some builders were confused. To avoid any misunderstanding, in Chap. 9, p. 6 of the 3-place plans, and Chap. 9, p. 9 of the Mark IV plans, add the instruction: "Before mounting the landing brake on LB-19 and the hinge, it will be necessary to trim away most or all of the 10" x .7" protrusion on the leading edge so the brake will retract into the depression flush with the fuselage bottom".

Keith also called to our attention that on the large fuselage cross section drawing (A-9 for the 3-place, M-13 for the Mark IV), we show the landing brake hinge mounted to LB-23 with AN3 bolts and nutplates, rather than the AN525 screws and aluminum slugs called for in Chap. 9 of the construction manual. Please make a note on the large drawing to install per instructions in Chap. 9.



  1. When epoxying parts together, like installing the bulkheads, instrument panel, seat back, etc. in the fuselage, all joints should be taped both sides, whether specifically instructed or not.

  2. Holes through bulkheads or instrument panel need not be glassed.

  3. Several builders have asked our opinion of mounting the fuel selector valve on the firewall and operating it remotely with a torque tube to avoid having fuel lines through the cockpit which might be a source of leaks or vapor lock. The Varieze was designed this way back in 1976 with the fuel selector valve mounted on the firewall and operated with a torque tube and universal joint. The experience of builders was not good. The torque tube caused spongy action, and it was difficult to feel the detent when the handle was in the correct position. If the valve stuck (which happened surprisingly often), not enough force could be applied to free it. There were forced landings and accidents. When the Long EZ was designed, the fuel valve was relocated in the front seat in the thigh support, where the pilot could operate it directly, and which necessitated running fuel lines through the cockpit. This solved the problems with the fuel valve, and didn't cause any problems due to fuel leaks or vapor lock. When we designed the Cozy, we thought it was even better to mount the fuel valve in the middle of the front seat, where either occupant could operate it directly and the fuel lines were restricted to the back seat. We have had no reported cases of fuel valve sticking or fuel line leaks in the Cozy. The FAA has an extensive file on fuel valve related accidents in almost every type of aircraft - experimental and factory built. There are no cozys on this list yet and we hope there will never be.

  4. For the benefit of new builders, we would caution you about using latex gloves. For some strange reason they seem to cause an allergic reaction with some people. It is thought that they cause ones hands to perspire and the pores to open up, and something from the epoxy comes right through the pores of the latex into the skin. Barrier cream and no gloves seems to offer better protection. If you must wear gloves, vinyl gloves are a better choice.

  5. We have been looking for a better way to shape fairings, like at the junction of the landing gear and fuselage. We tried a new idea. We bought some children's Play Doh at our local K-Mart, molded it around the fuselage-gear leg, and layed up 2 plies of BID. After cure, we cut through the middle of the fairing (this is necessary to let the gear flex), removed the gear, dug out the clay, and put it back in the can for our grandkids' next visit. Anyone have a better idea?

  6. Finishing. After contouring with the West System epoxy-micro, we recommend the use of a high-build epoxy primer (don't use Featherfill or non-crosslinking solvent based primers). We prefer the epoxy primer made by Vildng Paints, 100 W. 78th St. Richfield MN 55423 (612) 866-1212. It is available in gray and yellow. We spray a thick coat of gray first, and a lighter coat of yellow on top. When we sand, we go through the yellow in all the high areas, but the low areas remain yellow. If we go through the gray areas before getting down to the yellow in the low areas, we know we need to do more filling.


In NL#35 we reported on Uli's experience losing an oil seal, the importance of proper crankcase venting, and that it is possible to install a crankshaft seal retainer to prevent the seal from coming loose. Shortly after sending out the newsletter, Bruce Tift called to say that he had lost an oil seal but fortunately had been able to save his engine, but he knew of other Long EZ builders who were not so fortunate. He said this happens more often in pusher airplanes than most people realized. We called up Lycoming again and asked if it was just possible that in a tractor type airplane you might have a 200 mph velocity pressure helping to hold the seal in, but that in a pusher type you would have a 200 mph velocity suction trying to pull the seal out, and there is nothing but contact cement to hold the seal in. The tech service engineer pooh poohed the whole idea and said if the engine was put together and vented properly you couldn't lose the seal. He said he even knew of a case in a tractor type airplane where the seal had come out, there wasn't a loss of oil, and it wasn't even discovered until quite some time later. For some reason he didn't convince me that there was nothing to worry about, and you can be sure the Mark IV will have a seal retainer installed.


  1. Cozy 3-place 130 TT, 1990, 1054 lbs. empty, 1850 lbs. gross, 0-320 Lyc. 160 hp. 1720 TT. IFR equipped, many extras. $61,500. Contact Jeff Russell (919) 961-5631.

  2. Cozy 3-place 120 TT, 1989. Excellent workmanship. 0235- L2C Lyc. 118 hp. 170 mph cruise, full vacuum, Mode-C, Loran, Nav-Com. Heavy duty brakes. Flies great! $42,000. Contact Dave Mendenhall (513) 553-4513.

  3. Plans for building a T-hangar for either a 3-place or 4-place Cozy, requiring only $1250 for mwrials, not including doors. info pack $5. Complete plans $80. Jeff Russell (919) 961-5631.

  4. 13 lbs. of S-glass rovings left over after repairing my landing gear. $85. Contact Keith Spreuer (619) 745-2218.

  5. 2-1/4' mech. fuel press. gage 0-10 psi. matte white dial. $50
    Facet electric fuel pump for Cozy $20
    Std. brake discs and pucks for Long EZ $20
    Lyc. gear for RIH Mag. $75
    AC mech. fuel pump for 0-320 4-8 psi 600TT $50
    Aircraft Spruce spinner SAE2 cut for prop $100
    Contact Vance Atkinson (817) 354-8064

  6. Fuel sight gages unaffected by either aircraft or auto fuel. $30/pair. Contact Vance Atkinson (817) 354-8064.

  7. Two Brock 4" nosewheels. Make offer.
    Marvel Schebler MA4-5 carburetor for 0-360 Lycoming, overhauled, yellow tagged and never used. Make offer. Two Bendix mags for 0-360 overhauled and never used with new ignition harness. Make offer. Contact Nat Puffer (602) 981-6401.


Dear Nat,

I have my Cozy N5185Q up for sale because I want to build a Mark IV. I love to fly, but I also love to build and can't afford to do both. I would appreciate you passing the word.

I am a very experienced TIG welder on stainless steel and would like to talk to you about making Cozy exhaust pipes. Please keep me in mind if your other supplier doesn't come through for you.

Dave Mendenhall

Dear Nat,

I just received the newsletter and enjoyed all of the stories. The numerous photos are a real inspiration to keep working.

Last weekend I flew to Avon Park and met Charlie Larsen at the field. It was great to see another Cozy Mark IV builder, and a retired dentist too! He took me to his home and showed me his Cozy. Fuselage was looking good, and he was working on the gear. If possible every builder should have a close friend just a chapter ahead! Needless to say, I took a few photos for future reference.

My project is moving along. I took a two week break to completely clean my garage and paint the floor a light color, and add a few overhead lights. Then I shelved my epoxy balance (which worked fine) and spent a few hours cleaning up and repairing an epoxy pump. Now I'm ready for serious progress. My first milestone was reached today as I completed the fuselage bulkheads, and started the jig construction for the sides. Slow, but the quality is there.

Best wishes with the proof of plans model. By the way, I plan to attend Oshkosh '92 and will attend your Cozy dinner. Thanks for the newsletter and connecting me with Charlie.

Stephen Blank

Dear Nat,

N76PJ has flown off its 40 hours and has been jetting around quite a bit. We usually try and get over to Sedona or Prescott to see some friends quite often. I am having to add ballast to the rear starter pad in order to carry my wife along in the front seat. At my current A/C weight and cg. I can't get the cg. aft of center even at gross. Empty wt. 828# A/C cg. 109.9. Together my wife and I weigh in at around 310. Any thoughts on this other than go on a diet? (I sent some suggestions to Pat).

We've been having a ball in the Cozy and encourage all would be Cozy owners to hang in there cause it's all worth it. Hope to get over to see you soon.

Pat Young

Dear Nat,

The construction on of Cozy #501 plods along. I purposefully waited until after the price increase deadline to renew on the newsletter so I could give you more money (believe that and you may want to look at my swamp in the back yard on which to build a hangar). Actually, Nat, I think you let us get by too cheaply on the newsletters. The value is definately there and I wouldn't squawk if you uped the price by another $5.

Let me bounce a little idea off you. I've been thinking about a nationally maintained Cozy Data Base for a while. There have been a couple of guys that have made indexes on the newsletters and have been good enough to make them available and that is a step in the right direction. What I've got in mind is to take a compilation of those indexes and maintain it on an easily accessible information system like Compuserve for the ever increasing number of us who are somewhat computer literate. What we need is some Cozy builder who is also a computer whiz to work out the details and act as an editor. Maybe as a supplement to the newsletter, you could maintain commonly asked questions and answers. Who knows, might cut down your letter and phone traffic. Well, if you know anybody in the aforementioned pidgeonhole (Cozy builder/computer whiz) maybe pass the idea along to them.

In closing you'll find my check for 2 years of great newsletters and thanks for keeping the dream alive!

Doug Jones
8146 Whistle Wing Court
Orlando, FL 32817

Editor: If anyone is interested is working with Doug, please feel free to contact him.

Dear Nat,

After nearly two years and 175 hours, N267CZ is still a thrill to fly. I still receive a lot of admiring comments from people locally at the airport as well as at fly-ins I've attended.

I've made most of the recommended modifications and like you, I'm considering installing a Navaid wing leveler. I agree that it's a good safety feature for non IFR pilots. We hope to see you at Sun N Fun next spring.

John Ashe

Editor: We don't think the plans model Mark IV will be done in time, but you can count on the following year.

Dear Nat,

Martine and I have finished Chap. 7 as of today. So far, so good.

As you know, I started out using Safe-T-Poxy, but soon ran into problems. Basically, my skin started to fall off my hands and fingers. I was using Series 8 hand cream. After consulting you and the local EZ squadron experts, I have switched to RAE with satisfactory results so far. After switching, it occurred to me that Series 8 is not water resistant, so that when you grab a cold one in the midst of a long, hot session of layups, the moisture on the glass washes off your protection. I have now gotten a sample of a product called Derma Shield, which is water resistant. It takes about 5 good washings to come off. I got it from Jim Newman at Infinity Aerospace, PO Box 12275, El Cajon, CA 92022-2275 (619) 448-5103. It is $9.95 for a 2 oz aerosol foam can, and $24.95 for a 12 oz can. It comes out like shaving cream, and seems to work very well. I am told the large size is good for about 370 applications.

Most people use epoxy pumps which cost $180 or so. They are metered for either RAE of Safe-T-Poxy. When I decided to switch to RAE, Dave, a local Cozy builder, came up with a slick way to convert the pump, and it works great. Simply drill one hole to move the pivot bolt along the operating handle to a point 3.5" from the far connecting link. This changes the ratio from 45: 100 to 1:4. An added advantage is, now you can convert it back just by moving the pivot bolt back to the original hole.

Martine and I enjoyed seeing you and Shirley, and the others, at Prescott. I am enclosing some snaps of our cozy gathering under the wing of 22CZ. I picked up my instrument rating the week before, and got to use it getting out on the way to Prescott.

We are working along very happily together. Many times we have remarked how lucky we are that both of us are tackling the project - it seems like it would be too much for one person to handle alone; sometimes it seems like too much for the two of us.

Very truly yours,
James M. Allen

Dear Nat;

All continues to go well with flight testing. I have 34 hours on N456DP now and it has performed flawlessly. I'm looking forward to getting out of the test area. I have been in no hurry to fly off restrictions. I've been trying to enjoy the time in addition to making it meaningful, allowing time between flights to about what was accomplished, analyse aspects of envelope expansion, both speed and weight, and looking for things that a rush test period would not allow time for.

The weather here in Homer has slowed down the process slightly - being a coastal community most of the weather heading into the state hits us first. I haven't been able to fly at all for about the last week due to weather, and am itching to wrap things up so that I can make my first trip to Anchorage, normally a 5 hour drive; in the Cozy, a 40 min flight. There is lots to see in the state and from are a surprising number of hard surfaced runways to allow me to see most of it. Its a big, big state, but the Cozy should cut it down to size.

One of the reasons I'm writing Nat, is to ask a favor of you. As designer I'm sure you personally know people that would like a Cozy or Mark IV who don't have the time or volition to build. I miss building terribly. I enjoy it immensely. If someone should ask you, would you mind giving them my name and address? I would be willing to fly to their location and do whatever they would like done for a reasonable cost. If I worked on a project full time, I could complete it in less than a year. You know my background in homebuilding. I'm 44 years old and have been in management in the grocery business for the last 10 years (until recendy-stepped down due to job dissatisfaction and wanting a career change).

I hope all is well with you and your wife. I look forward to meeting you at Oshkosh '92. I'll be flying down with a friend who has the only flying RV-6 in the state. We have been doing a lot of formation flying together. He has been flying off restrictions also. Enclosed is a snapshot. Mt. Redoubt is in the background.

Take care,
Dave Petrosino


[Cozy MKIV Information]