Date: Sat, 18 Sep 1999 21:22:34 -0500 From: David Domeier Subject: COZY: Learn something new everyday.... You younger guys may not find this of much interest, but there is some evidence that it is important to learn something new each day to keep one's brain fit. It is especially so as you grow older....has something to do with endorfs, whatever they are. (I know a little about a lot of stuff, and read that somewhere) Well, I learned something about the Cozy MKIV yesterday that may interest you. Every airplane has a little nuance or two that will bite you if you're not spun up on what's going on. This is especially true of relatively high performance machines and the Cozy is that. About a week ago a LEZ builder called and asked for a ride in the Cozy to get the feel of flying a canard. He's very close to first flight so we made a date. Yesterday was the date and we took off and headed for an uncontrolled airport with 3800' feet of runway. I figured I'd let him do some steep turns, show him a couple landings and let him take off to get the PIO's under control and our of his system. That seems to be the major problem new pilots have flying a canard. We accomplished that and headed back to home base, I'm flying and decide to make the approach like I always do - 80 knot final, power off glide to a flare. (I had been using 90 or 95 at the remote airport, but the speed seemed too fast - we floated somewhat - but the airplane did flare nicely) I remember calling out the airspeed and sink on final to illustrate how stable the airplane is. (81 knots, sink 600) At about 30 feet above flare we encounter a down draft, or negative wind shear, or some mysterious sucking gravity force, and began to sink rapidly. I added power and came full aft with the stick but could not arrest the sink. The nose gear hit the runway first - very hard - then the mains - also very hard - and we were sprung back in the air as the gear flexed itself back to normal. By that time there was no airspeed left and we landed again very quickly but not quite as hard. I was certain there was major structural damage. We cleared the runway and much to my surprise, the airplane taxied normal - none of the struts had broken as far as I could tell and the tires appeared to be inflated. At the hangar, a lengthy post flight inspection revealed no structural damage. (whew) There were no cracks at the gear attach points or gear axles. The nose strut faring was delaminated from the forward face of the strut for about 18". (which conveniently revealed the forward face of the strut) It looked perfectly normal as did the nose gear. There was some cosmetic damage - the main gear strut had flexed up so far it cracked the fuselage farings and also slightly damaged the center gear strut cover. Not to drag this any longer - what happened was that this pilot had become very accustomed to flying solo with the cg at 102 and at 1400-1500 lbs gross. This evening I ran my spread sheet cg calculator and was informed that the cg for that flight was at 98.45 and the gross weight about 1775. The bottom line is, when you fly the MKIV with someone up front, be aware 90 knots on final is just fine. Anything less than that and the airplane may not fly out of a sinking event. By the time I had the power up, we hit. dd Incidently, I fixed the cosmetic stuff with flox over night and flew to Rough River today with Curt Smith - me in the Cozy and Curt in his LEZ. It was a very rare, nice day to fly, and I was mightly pleased I did not wreck my airplane yesterday. The MKIV is tough and will take some abuse now and then, that's for sure. From: Epplin John A Subject: RE: COZY: Learn something new everyday.... Date: Wed, 22 Sep 1999 09:56:56 -0500 Dave and all I have been wondering about angle of attack instruments. Don't hear anything concerning these and canards. Is there some reason that they are not as valuable on a canard? Where would one mount the sensor? Could you use the wing surface pressure sensors used by some of the new electronic devices? AOA seems like a valuable aid, I only have limited experience with these but the idea appeals to me as presenting more useful information than air speed during the low speed part of flight such as approach. Anyone know about AOA and canards? John Epplin. Mk4 #467 > -----Original Message----- > From: David Domeier [SMTP:david010@earthlink.net] snip > I remember calling out the airspeed and sink on final to illustrate > how stable the airplane is. (81 knots, sink 600) At about 30 feet above > flare we encounter a down draft, or negative wind shear, or some > mysterious sucking gravity force, and began to sink rapidly. I added > power and came full aft with the stick but could not arrest the sink. > The nose gear hit the runway first - very hard - then the mains - also > very hard - and we were sprung back in the air as the gear flexed itself > back to normal. By that time there was no airspeed left and we landed > again very quickly but not quite as hard. I was certain there was major > structural damage. > > Date: Wed, 22 Sep 1999 17:16:43 -0500 From: David Domeier Subject: Re: COZY: Learn something new everyday.... John, There was a lengthy discussion here about AOA some time ago. It should not be difficult build a simple system with a vane, a shaft with a good bearing and a scale inside. Some day I will do it. There are a electronic units available for experimentals but they aren't cheap. With regard to the MKIV hard landing last week, I am sending the airspeed indicator back to UNA today. I bought this unit new from Wicks last month. When Curt Smith and I flew down to Rough River last Saturday I was indicating 20 knots faster than Curt at 5500. I have since flown with another buddy who has an IFR certified Twin Commanche and on his wing I was 12 knots faster. I also moved the pitot tube to be sure it was out of disturbed air and the numbers were exactly the same on the second flight. (The heated pitot mounted parallel to the fuselage is just as accurate as a pitot aimed straight ahead. All the big jets have it parallel to the fuselage and I figure the MKIV cruises at about mach .25 so why not? It works just fine and I proved it today) The conclusion is, when the MKIV began to sink it was actually flying at 68 knots or less. With the cg at 98.45 and the weight at 1775, it is no wonder it would not flare. A calibrated AOA system would have been very nice. One of the electronic devices would have been going nuts with red lights, bells, and whistles, on that approach. I've learned another thing about airspeed indication and static pressure. The reason I bought the new indicator is 'cause my old unit, which was salvaged from my LEZ and was some 20 years old, was never steady. It always quivered plus or minus 5 knots even after an overhaul and drove me nuts. When I installed the new indicator, I moved the static port aft 'cause it was mounted where the fuselage is still expanding, about 4' aft of the pitot tube, and could have had disturbed air. As I will explain, it was disturbed air and the ASI is VERY sensitive to unsteady static pressure. The new airspeed indicator was steady as rock in smooth air and I was happy. Guess what I learned this morning when I hooked up the old indicator in parallel with the suspect new one to compare numbers - it too was steady as a rock! The quivering was caused by unsteady static pressure and I never needed a new ASI! (the old one is 6 knots less than that new one which was no surprise. I always figured it indicated about 5 knots fast in the LEZ) At present, I have 2 static ports left and right connected with a tee. The left port is about 20 inches down and aft of the fresh air NACA inlet. When I close the left air inlet nozzle in flight the NACA scoop doesn't know what to do with the incoming air that isn't going anywhere so it goes whomp-whomp as it builds up pressure and releases it outside along the fuselage. You can hear it and also see it on the ASI as it jumps up and down 20 knots. The pressure surges are detected at the static port some 20 inched down and aft of the NACA scoop. I am going to close that intake and cross duct from the right side - there's plenty of ram air from one of these intakes. For some inexplicable reason when the right intake is closed, it does not go whomp-whomp. Building an airplane is supposed to be a learning event and that it is. Be aware that the cheaper ASI's are not certified and could be considerably at variance with the real airspeed of your airplane. I'm sure most of them are right on, but I have 1 that is not quite as close to real as I would like. dd From: cdenk@ix.netcom.com Date: Wed, 22 Sep 1999 22:06:08 -0500 (CDT) Subject: Re: COZY: Learn something new everyday.... Was said I think they both should be in the same locations on both sides, and similar airflow issues fore and aft. The idea is the "T" fitting equal length tubing from both static ports will average slips, skids and other issues. I notice when in rain, there are occasional jumps in static port connected instruments. As long as the airspeed is consistant, testing should determine the correct approach speeds, etc. to use. I'm not saying, one should live with an inaccurate indication, just that testing should determine the speeds to use as reference for operations, and not what is published in some book. IFR instrument tests DO NOT include the airspeed indicator, just altimeter and transponder. But, the FAR's require when IFR (not sure without looking it up what I mean), and deviating more than 10 Knots from flight plan speed in cruise, that the pilot notify the controller. This gets interesting since one prop I have, will get 8 knots more in a small altitude band. Date: Thu, 23 Sep 1999 21:44:29 -0400 From: "Edmond A. Richards" Subject: COZY: Runway Lengths Can you folks that are flying offer an opinion on practical runway requirements for the Cozy Mark IV. The local airport here in St. Pete (SPG) has two hard surface 3000 ft. runways. My question is, will I regret keeping my plane at this airport and routinely "fighting" the runway length? Or is the 3000 length comfortable? Thanks for the input. Ed Richards Cozy Mark IV #88 - Getting ready to fly. Date: Fri, 24 Sep 1999 05:35:09 -0400 From: Jeff Russell Subject: Re: COZY: Runway Lengths "Edmond A. Richards" wrote: > My question is, will I regret > keeping my plane at this airport and routinely "fighting" the runway > length? Or is the 3000 length comfortable? Mighty short. -- Jeff From: cdenk@ix.netcom.com Date: Fri, 24 Sep 1999 12:34:06 -0500 (CDT) Subject: RE: COZY: Runway Lengths If one flys light front seat the 3000' runway should be snuggly adequate. If planning long distance trips with full fuel, luggage, and 2 people in the front seat, I would not recommend. The front seat loading really changes takeoff roll big time. Although you are sea level, high temperatures are common there, and that will add to the roll. A month a go used 5300' of 7000' at elevation 7075'. From: "John Slade" Subject: Re: Re:COZY:garage door width required to deliver the bird Date: Thu, 23 Sep 1999 09:32:21 -0400 >I would think that inspirational or even just cool stories of your interesting >flights would be well within charter for this list. Agreed wholeheartedly. For example, DD's hard landing story may save others from a similar experience. Regarding dd's hard landing - I don't think this is a "Cozy problem". More a "new airplane" problem. I recall a similar experience in my Cherookee 160. My brother was flying. Numerous things were different for him - He's used to a 180 solo in lower [UK] temperatures into a very short field [requiring minimum approach speed]. The 160 was close to gross weight on a hot [for USA] day. We were low & slow despite my prompting. At 50 feet we "fell out of the sky". I added full power on the way down and flew us away from the bounce. I think we dented the runway. Moral - long runways and "high & fast" is better when unfamiliar with the aircraft or conditions - then shave off a few knots gradually as you get used to the handling under different circumstances. I would like to hear more stories from Cozy flyers. John Slade Cozy #757 Chap 19 From: "Wilhelmson, Jack" Subject: RE: COZY: Runway Lengths Date: Fri, 24 Sep 1999 08:46:47 -0400 Edmund: I have a CozyIII with a o320 and I fly off 3000 ft all the time. Very comfortable for me. A lot depends on your particular airplane and how it is set up. I have seen CozyIIIs That take twice the ground roll that mine does, due to main gear placement, ground angle, Etc. On landing, good speed control and good brakes are important on runways less than 3000. Jack Wilhelmson N711cz From: cdenk@ix.netcom.com Date: Sat, 25 Sep 1999 07:06:32 -0500 (CDT) Subject: RE: COZY: Runway Lengths All indications are a pilot contollable propeller increases the accelaration rate, which means the aircraft achieves takeoff speed quicker, which means shorter runway, but I suspect it still would be marginal out of 3000' at higher temps. The controllable props cost around $8000 I think. With a pusher one should always have a spare prop available that is FAA approved for the airframe since damage from debris is not unusual. Thats an investment of $16,000 as opposed to $1600. Requires deep pockets! I would recommend either a different airport or aircraft. There are all sorts of compromises with aircraft. Date: Sat, 25 Sep 1999 09:05:48 -0400 From: Jeff Russell Subject: Re: COZY: Runway Lengths allan aaron wrote: > > How much difference will a constant speed prop make to the equation? > > Allan A I have seen 2 AeroCanards fly with MT props and many Velocities. It normally takes 1000 feet or more to rotate depending on loading. I have taken over 3000 feet to rotate on a hot, heavy day with a CG of 97. The CS props seems to cut in half the rotate distance. Landing with a CS prop will take power above idle or you will fall out of the sky. The Glide slope seems more normal with a FP prop that seems flat. -- Jeff Russell/AeroCad Inc. E-mail: Jeff@aerocad.com 2954 Curtis King Blvd. Ft. Pierce, FL. 34946 Shop# 561-460-8020 7:00am to 3:30pm Home# 561-344-6200 Website: http://www.Aerocad.com Composite workshop info: http://www.Sportair.com From: "Nat Puffer" Subject: COZY: Angle of attack indicators Date: Sat, 25 Sep 1999 20:52:25 -0500 Cozy Builders, I have been reading a lot of postings about angle of attack indicators and can't understand why some people are apparently enamored with them. I have heard it claimed that that is what Naval Aviators use in the Navy to land on carriers. Well, I would like you to know that I went through carrier training and qualified on carrier takeoffs and landings in the Navy in 1945 piloting a TBM Avenger, and also checked out in the Dauntless SBD, the F6F Hellcat, and F4U Corsair, which were all considered to be high-performance aircraft, and there was no such thing then as angle of attack indicators. As a matter of fact, there was no such thing used in WWII, even in the trainers I flew (N2S, N3N, SNJ, etc.) nspite of the fact that it is a simple device. We learned to fly our airplanes and were required to fly them at minimum speed in our carrier approaches, strictly following the commands of the landing signal officers. When we did the aft c.g. testing on the Cozy Mark IV, I installed an angle of attack indicator to record the angle of attack at the point of minimum flying speed and/or stall on video. It was simply a vane on the outside of the fuselage connected to a calibrated pointer on the inside of the fuselage wall, and a mirror, so the video camera would record the position along with the airspeed, rate-of-climb/descent, etc. We were interested in knowing whether the maximum angle of attack was a function of c.g. position, and how it would change in a stall. After our tests were completed, I saw no useful purpose in keeping it, and removed it. There is a danger in thinking that you have to have instruments to tell you everything you otherwise would learn to do by visual observation of aircraft attitude, airspeed, and rate of descent. If you don't learn to fly by the seat-of-your-pants, and have to depend on instruments, if anything goes wrong with those instruments, you are in deep doodoo. I believe the most fun in flying is when you follow the KISS principle. Best regards, Nat Date: Sat, 25 Sep 1999 19:31:45 -0700 From: "LCDR James D. Newman" Subject: COZY: Re: Learn something new everyday.... Hi John and All, > Is there some reason that they are not as valuable on a canard? No. > Where would one mount the sensor? Depends on the design. There is a good article in the July '99 Sport Aviation, page 108, about AOA and indicators. > Could you use the wing surface pressure sensors used by some of the new electronic devices? Yes. > AOA seems like a valuable aid, . . . Ohhh, it sure is. I will have one. > I only have limited experience with these but the idea appeals to me as presenting more useful > information than air speed during the low speed part of flight such as approach. Airspeed, altitude and VSI lag (particularly the slower you are), and can be inaccurate (as Dave Domeier found out). > Anyone know about AOA and canards? INFO: Aircraft Descent Velocity (V) is calculated per FAR 23.473(d) as: V = 4.4 (W/S)^.25 [f.p.s.] The range allowed is a minimum Descent Velocity of 7 f.p.s. (420 f.p.m.), which corresponds to a wing loading of 6.4 lb/ft^2, and a maximum of 10 f.p.s. (600 f.p.m.), corresponding to a wing loading of 26.9 lb/ft^2. Using a Gross Weight of W = 2000 LBS.; and a Long-EZ wing plus canard area = 94.9 ft^2, V = 9.427 f.p.s. (565.62 f.p.m.). Typical landings are normally well below the 7 f.p.s. for any gross weight. A NASA study shows that the average landing (including airliners) is only 3 f.p.s./180 f.p.m. - which is considered a hard landing by airline passengers. [Info: 94.9 ft^2 X 26.9 lb/ft^2 = 2552.82 LBS. gross weight] While canard aircraft are usually stall and spin proof when flown within the CG envelope, they can get into a high sink rate. So, accurate instruments, particularly if you don't have an AOA, is a good idea. Knowing your canard stall speeds for a wide range of aircraft weights and density altitudes where you are landing is a good idea too, or install an AOA. Infinity's Forever, JD Date: Sat, 25 Sep 1999 22:21:42 -0700 From: "LCDR James D. Newman" Subject: COZY: RE: Runway Lengths > All indications are a pilot contollable propeller increases the accelaration rate, which means the aircraft achieves takeoff speed quicker, which means shorter runway, . . . Very true. > . . . but I suspect it still would be marginal out of 3000' at higher temps. Take-off distance usually is half the distance of a fixed pitch prop or better. > The controllable props cost around $8000 I think. WhirlWind's 20 lb. 3 blade constant speed prop is $6500. > With a pusher one should always have a spare prop available that is FAA approved for the airframe since damage from debris is not unusual. Thats an investment of $16,000 as opposed to $1600. Requires deep pockets! No deep pockets required. If you're going to have a spare prop around, just have a 2 or 3 blade fixed pitch prop around that you've used on your plane before. Or buy an extra blade for your constant speed prop. MT charges $300 per blade to fix it's blades for their constant speed props, for example. Just fly with the fixed prop until your blades come back repaired. > There are all sorts of compromises with aircraft. There sure is :-) . Infinity's Forever, JD Date: Mon, 27 Sep 1999 09:43 -0500 (CDT) From: Michael Pollock Subject: Re: COZY: RE: Runway Lengths LCDR James D. Newman writes: >No deep pockets required. If you're going to have a spare prop around, >just have a 2 or 3 blade >fixed pitch prop around that you've used on your plane before. Or buy an >extra blade for your >constant speed prop. >MT charges $300 per blade to fix it's blades for their constant speed >props, for example. Just fly with the fixed prop until your blades come back repaired. JD, You are changing the engine/propellor combination if you remove the CS prop and go back to a fixed pitch. That requires a new inspection from your DAR or FAA, otherwise, you are asking for a denied insurance claim should something happen. Date: Mon, 27 Sep 1999 12:54:18 -0700 From: "LCDR James D. Newman" Subject: COZY: Re: Runway Lengths Hi Mike and All, > LCDR James D. Newman writes: > > >No deep pockets required. If you're going to have a spare prop around, just have a 2 or 3 blade > fixed pitch prop around that you've used on your plane before. Or buy an extra blade for your > constant speed prop. > > >MT charges $300 per blade to fix it's blades for their constant speed props, for example. Just > fly with the fixed prop until your blades come back repaired. > Michael Pollock wrote: > JD, > You are changing the engine/propellor combination if you remove the CS prop and go back to a fixed > pitch. True. > That requires a new inspection from your DAR or FAA, otherwise, you are asking for a denied > insurance claim should something happen. As I mentioned above, if you've used a fixed pitch prop before and switched to a constant speed prop, the approval you mention has already been done. Also, you could get a one time ferry permit to use your/a spare fixed pitch prop to get home. HTH. Infinity's Forever, JD Date: Sat, 25 Sep 1999 20:43:15 -0400 From: "Edmond A. Richards" Subject: COZY: Re: Runway Length Thanks to all who responded to my question on adequate runway lengths. Though the comments are a little mixed I think I get the overall picture. At this point I may have a choice of airports for home base. The one I prefer is the one with the shorter (~3000) runways. The other is a larger airport with much more commercial jet traffic and of course a more expensive hangar but the minimum runway length is 5000. Decisions, decisions. Thanks again for the help. You guys are great! Ed Richards Cozy Mark IV #88 Getting ready to see if the engine will start. From: N433DP@aol.com Date: Sat, 25 Sep 1999 21:03:35 EDT Subject: Re: COZY: Re: Runway Length In a message dated 9/25/99 5:47:17 PM Pacific Daylight Time, EdRichards1@compuserve.com writes: << At this point I may have a choice of airports for home base. The one I prefer is the one with the shorter (~3000) runways. The other is a larger airport with much more commercial jet traffic and of course a more expensive hangar but the minimum runway length is 5000. Decisions, decisions. >> Keep the Cozy at the 5000 ft until you are comfortable with the shorter run way. Then move to the one you really want. Date: Mon, 27 Sep 1999 16:48:13 -0400 From: Jeff Russell Subject: COZY: Re: Runway Lengths Michael Pollock wrote: > JD, > > You are changing the engine/propellor combination if you remove the > CS prop and go back to a fixed pitch. That requires a new inspection > from your DAR or FAA, otherwise, you are asking for a denied insurance > claim should something happen. Carl Dink, and Nat, this is a question for the both of you and for any other people that might be out there who are changing props all or some of the time to find the best combination for themselves and others builders that will be flying these kind of pusher airplanes? Question? Are you calling the FAA and asking them for a new Air worthy certificate if you try a new prop? Is this required by the Fed's. This to me would be a major modification. -- Jeff From: "John Slade" Subject: Re: COZY: Angle of attack indicators Date: Tue, 28 Sep 1999 12:15:39 -0400 Nat, >Well, I would like you to know that I went through carrier training and >qualified on carrier takeoffs and landings in the Navy >in 1945 piloting a TBM Avenger, and also checked out in the >Dauntless SBD, the F6F Hellcat, and F4U Corsair, which were all >considered to be high-performance aircraft, and there was no such >thing then as angle of attack indicators. While I'm sure we all respect your knowledge and experience, I don't feel that the situation in 1945 is a valid argument for not using a modern device. You might as well say "we used to navigate by road signs" to suggest that a GPS is not worthwhile. >If you don't learn to fly by the seat-of-your-pants, and have to depend >on instruments, if anything goes wrong with those instruments, you are >in deep doodoo. Of course this is true, but once you HAVE learned to fly by gut [as we all do], having added instrumentation from which to fall back can't hurt. e.g. Using a navigation analogy - A new pilot learns pilotage, THEN learns how to use ADF and VOR. If the VOR fails he has ADF and pilotage to fall back on. Then he/she learns GPS. If the GPS fails there is always VOR and so on. An AOA is just a better stall horn. The more levels of safety we have the better, don't you think? >I believe the most fun in flying is when you follow the KISS principle. Flying an open cockpit with no radio is fun too, but we'd be in a real mess if everyone did it. Regards, John Slade Cozy #757 http://kgarden.com/cozy From: cdenk@ix.netcom.com Date: Mon, 27 Sep 1999 18:08:41 -0500 (CDT) Subject: COZY: Prop changing Was asked All comments are my own opinion! Changing a prop is a major modification and requires F.A.A. approval. The first several Sensenich props I tested, each had a new airworhiness certificate. I have a very good working relationship with the local F.A.A. people. For those props, the new certificate was several times delivered to my house on a Friday afternoon, and once Saturday morning at the airport. Then the testing settled on 2 different prop design families. At that point the F.A.A. issued a letter of approval for any pitch of those 2 families, providing necessary engine R.P.M. was available, weight and balance adjusted, and a log book entry made. I carry this letter with the operating limitations. The letter is a result of the Sensenich props being made from certified materials and work standards the same as their certified props. Sensenich can certify a prop for an engine/airframe if they generate enough business to justify the effort. I'm told its not that difficult for them. Note that every F.A.A. office may handle this differently. I have seen operating limitations that say "any wood propeller". I still think I would handle that a major mod. The big issue is if in court with one or a panel of judges, or a jury, how would the situation be interpeted. This is one of the major reasons to have a spare prop, all set to go approval wise. Just have it sent, and bolt it on with a log book entry. Would someone like to with a strange F.A.A. office try to get on the way without hours in the pattern or test area. With a factory built airframe, just get a prop from a P.M.A. or S.T.C. and go, after a certified mechanic bolts and enters logbook. Date: Mon, 27 Sep 1999 06:21:52 -0400 From: "Marc J. Zeitlin" Subject: COZY: Runway Length Michael Pollock wrote; > You are changing the engine/propeller combination if you remove the > CS prop and go back to a fixed pitch. That requires a new inspection > from your DAR or FAA, otherwise, you are asking for a denied insurance > claim should something happen. This is a good point. This would be the case with someone who has a 3-blade fixed pitch prop and has a 2-blade boxed up to send as a spare if anything happens to the 3-blade. I wonder if the FAA would give a signoff on BOTH configurations, if you did a 40 hour period for the main prop and a 10 hour (or whatever they required) on the backup prop? It would certainly be worth the effort - they you could legally fly (with insurance) with either set of props. -- Marc J. Zeitlin mailto:marcz@ultranet.com http://www.ultranet.com/~marcz/ From: cdenk@ix.netcom.com Date: Mon, 27 Sep 1999 18:46:52 -0500 (CDT) Subject: COZY: Spare prop Was asked I certainly would persue this issue. The F.A.A. probably would want their usual test/proving time and landings, which I certainly agree with. I always discuss with the F.A.A. the issue, we work out as a team effort a solution, usually requires me to write a letter requesting the action describing the issue, and they respond with the necessary paperwork. I do, they do, all as discussed and agreed. When I changed my propeller extension recently, they indicated only a logbook entry with weight and balance was required. I had indicated if that was OK, I would send a registered letter with return receipt confirming the conversation. That was fine, it would be put in my file. I now have the receipt attached to a copy of my letter. This procedure was given me by an Avemco Insurance vice president. From: Militch@aol.com Date: Wed, 29 Sep 1999 12:50:43 EDT Subject: COZY: Re: Runway lengths I must admit I got a bit pale when I read the recent letters on recommended runway lengths. The literature for the Cozy quotes take off distances of 1200 feet. I always expected that with higher temperatures, sloping runways, obstructions, higher payloads, cg variations, etc. this would be an absolute minimum, but that 2200 to 2500 feet would be a safe and reasonable number. The consensus seems to be 3000' minumum and preferably 4000'. The GA airfields in this area are typically 2200' to 2400'. Go beyond that and you are talking business operations with private jets, etc. that charge landing fees and generally make life complicated. Am I building a plane that can only use 2% of the fields out there, and that I have to base 50 miles from my house? To put a more positive spin on the question - what do I have to do to make 2200' runway operations safe? IO-540 with a constant speed, reversible prop and a one passenger limit :-) Regards, Peter Militch Cozy Mark IV #740 Chapter 7 From: MARC_ZEITLIN@HP-Andover-om1.om.hp.com Date: Wed, 29 Sep 1999 14:09:36 -0400 Subject: COZY: Runway lengths Peter Militch wrote: > To put a more positive spin on the question - what do I have > to do to make 2200' runway operations safe? IO-540 with a constant speed, > reversible prop and a one passenger limit :-) I KNOW there are people operating V.E.'s and L.E.'s from 2000 - 3000 ft. runways - some of them even on grass. I have watched a O-235 powered L.E. take off from a 2700 ft runway on a 90 degree day, and use about 1/2 the runway. I watched it land and turn off the runway in about 1500 ft. This is all at sea level. The Cozy, like all the canards, is NOT a short field aircraft. However, as long as you calculate density altitudes, know your CG position, and know YOUR aircraft's performance, these fields are eminently doable. Maybe not at gross weight on a hot day at 8000 ft. density altitude, but for my purposes, that will be a tiny percentage of the time. I will be starting at Hanscom field in Bedford, MA, which has a 7000 ft. runway. When I am comfortable that I can deal with 2500 ft. runways on hot days with full fuel, I may move to Minuteman in Stow, MA. This is a 2700 ft. runway. I have no qualms about this, as the power/weight ratio of the COZY is substantially more than that of the L.E. -- Marc J. Zeitlin marcz@ultranet.com http://cozy.canard.com Non Impediti Ratione Cognitanis (C&C) From: cdenk@ix.netcom.com Date: Wed, 29 Sep 1999 16:19:23 -0500 (CDT) Subject: Re: COZY: Re: Runway lengths Was asked You are only on chap. 7, thats very early. Sell the project, and build something else! All alternatives are compromises, but this is TOO short. BOth takeoff and landing distances. From: "Nat Puffer" Subject: Re: COZY: Re: Runway lengths Date: Wed, 29 Sep 1999 10:55:09 -0500 Peter, What is possible and what is safe are two different things. We have been in and out of 3000 ft runways either turning off or rotating half-way down. Yet one of our 3-place Cozys, overloaded, without heavy duty brakes, aborted half-way down a 3000 ft runway, couldn't stop, and went thru a fence. A constant speed prop will let you develop full-rated horsepower (180 hp) for takeoff, which is not possible with a fixed pitch prop. The latter only lets you develop about 134 hp for takeoff. So the constant speed prop accellerates faster and shortens the distance to rotation. Tim Merrill has a Mark IV with only 160 hp, but a constant speed prop, and he can rotate in a much shorter distance than we can. The smaller engine and constant speed prop is a nice combination, but it is more expensive and complex (more maintenance) The Mark IV was not designed for an IO-540, and we sure hope you don't consider it. We think it would be dangerous! Regards, Nat From: "astrong" Subject: Re: COZY: Re: Runway lengths Date: Wed, 29 Sep 1999 11:26:57 -0700 Peter, I read your e-mail on runway lengths with much interest, perhaps I can be of help. I have been flying my COZY III for the last six years from a dry lake bed.She has a 0320 150 HP engine , Field elevation is 1929 ft., runway length is 2000ft. For short hops we take off from our backyard. When we go on long trips Sun n Fun ,.Medford OR. full fuel max grossweight we fly to Barstow- Daggett (DAG) airport 5 miles SE of home, paved runways 5500 and 6500ft.and take off from there, Ofcourse we observe the fly before noon rule of the high and hot desert. Regards, Alex From: Militch@aol.com Date: Wed, 29 Sep 1999 16:25:29 EDT Subject: COZY: Runway lengths In a message dated 9/29/99 6:03:22 PM, Nat wrote: >complex (more maintenance) The Mark IV was not designed for an IO-540, and >we sure hope you don't consider it. We think it would be dangerous! > Thanks for the reply Nat. No, that was a joke. My choice is between an IO-320 with CS prop or IO-360 with a fixed pitch prop. I am building the Cozy strictly to plans with zero deviations. The FAA usually has local builders do their flight testing at Easton Airport on the Md. Eastern Shore and that is a nice, long runway. What I am hoping is that during my initial fly-off, I will be able to establish enough data points to understand the full limitations and capabilities of the plane, and that it will turn out to be safe to operate with a single person, mid-fuel and perhaps a mid to slightly aft CG, out of one of the shorter local strips. If I want to do a long cross-country with passengers, then that will require a hop to a longer strip, and my passengers and full fuel will get picked up there. I just mainly want to be able to fly by myself from local strips (five minutes away), and not have to drive 50 miles to take the plane up for a one hour flight. I am still enjoying the building very much. I sanded the bottom fuselage corners to shape this weekend. It took a bit of elbow grease, but the five or six hours I spent on the job passed in the blink of an eye. Regards, Peter Date: Thu, 30 Sep 1999 08:27:05 -0400 From: Paul Krasa Subject: Re: COZY: Re: Runway lengths I agree with Carl here. 2200' is to short for every day use. There is no margin for error. Throttles up the take off is committed, and landings will need to be spot on everytime. I am in my test period now, and with 20+ landings under my belt, I still have trouble putting it down in the first 1000' let alone on the numbers. I use minimum take off distance plus minimum landing distance as the minimum runway length. This is roughly 1200ft for take off and 1500ft for breaking, thus my minimum runway length is 2700'. I won't even attempt this until I can regularly put the airplane on the numbers. I have already used up all of a 5000' runway landing and stopping during my testing, and it scared the heck out of me. If you really need an airplane with the capability of going in and out of a 2200' runway, sell your project and build a RV-6 or buy a T-18. Both have good cross country capability and will be happy on a runway of this length. IMHO Canard aircraft do not meet the mission profile of taking off from a short runway all the time. Paul Long EZ 214LP At 16:19 9/29/99 -0500, cdenk@ix.netcom.com wrote: >Was asked > >You are only on chap. 7, thats very early. Sell the project, and build something else! All alternatives are compromises, but >this is TOO short. BOth takeoff and landing distances. > > > From: "Nat Puffer" Subject: Re: COZY: Glide ratio calculation Date: Tue, 9 Nov 1999 15:00:10 -0600 Dear Al, This information is in our Owners Manual. Do you have one? We charge $15 postpaid. Ken Brimmer ran his own tests, idle and engine off. If I remember correctly he said from 9,000 ft. he glided 23 miles, and of course, that was not down to sea level, so I think it was 23 miles in 7 or 8,000 ft. A long time ago I think I calculated that was about 3 or 3-1/2 degrees, and essentially agreed with the data in the Owners Manual. Regards, Nat ---------- > From: alwick@juno.com > To: cozy_builders@canard.com > Subject: COZY: Glide ratio calculation > Date: Tuesday, November 09, 1999 4:32 PM > > What sort of glide ratio should I expect in my Cozy mkIV when I lose > engine power? Assuming I maintain best glide speed. No wheel pants, but > all else stock. > I'm assuming I'll lose engine power during my test phase. I want to > program computer to calculate if I'm within safe gliding distance to > airport, instead of leaving this calculation to pilots already saturated > noggin. It'll reduce pilot workload and give me a reference when engine > fails. I figured I'd have display give me green, yellow or red image that > reflects my safe gliding distance. > I was watching friend do initial flights in his ez this week end. He > intended to stay within safe distance of airport, but clearly exceeded > it. After reviewing most of the cp accident reports, I feel this is > important tool I can readily accomplish. > Planning on just using distance formula and cartesian coordinates from > gps and airport. Throw in fudge factor for other parameters and it should > be meaningful. Perhaps I'll include velocity vector info. I'll test it in > my C150. > > I just need engine out glide ratio. Thanks. If it works, I'll share > program. > > -al wick > Canopy Latch System guy. > Artificial intelligence in Cockpit > Cozy sn 389 driven by stock Subaru 2.5 ltr 106% complete, Aug 00 first > flight sched.. > > ___________________________________________________________________ > Get the Internet just the way you want it. > Free software, free e-mail, and free Internet access for a month! > Try Juno Web: http://dl.www.juno.com/dynoget/tagj. Date: Tue, 09 Nov 1999 19:26:49 -0500 From: bil kleb Subject: Re: COZY: Glide ratio calculation alwick@juno.com wrote: > > [...] After reviewing most of the cp accident reports, I feel this is > important tool I can readily accomplish. > Planning on just using distance formula and cartesian coordinates from > gps and airport. [..] if you already haven't, you might do some research into the glide computers that sailplanes have used for years... -- bil From: alwick@juno.com Date: Fri, 19 Nov 1999 13:49:40 -0800 Subject: Re: COZY: Glide ratio calculation For those who expressed interest... I developed spreadsheet to interface with gps. Given the coordinates for my base airport and gps location, I have it calculate distance and safety margin. Plan on display showing green if ok, yellow or red if I'm behond gliding distance to airport. Was not too difficult, however, when testing accuracy by entering known coordinates for 5 airports, I encountered some bizarre bug that gives me good accuracy for all but one airport. Debugging. Anyone know the diam. of the earth at various lat and longtitudes? If I get this worked out I'll send this to someone for free download avail. -al > > I'm assuming I'll lose engine power during my test phase. I want to > > program computer to calculate if I'm within safe gliding distance to > > airport, instead of leaving this calculation to pilots already saturated > > noggin. ___________________________________________________________________ Get the Internet just the way you want it. Free software, free e-mail, and free Internet access for a month! Try Juno Web: http://dl.www.juno.com/dynoget/tagj.