Date: Sun, 18 Jan 1998 09:02:34 +0200 (GMT) From: pine@global.co.za (pine) Subject: COZY: Lenght of Cannard when widening the Fus Hi All I have seen lots of posting where people say they are or want to widen the fuselage. I also konw it possible to only widen the seatback, but how does the lenght of the cannard and that of the center spar, wings and so-on relate if the fus is made 2" wider from tip to end. I discused this with James Newman of Infinity who's oppinion I trust. But would like to get some more views on the subject. Many Thanks Pine Pienaar pine@global.co.za From: cdenk@ix.netcom.com Date: Sun, 18 Jan 1998 09:33:39 -0600 (CST) Subject: Fwd: Re: COZY: Lenght of Cannard when widening the Fus ------Begin forward message------------------------- From: cdenk To: pine@global.co.za Date: 01/18/98 09:53:21 Message-Id: <199811895321118467@> Subject: Re: COZY: Lenght of Cannard when widening the Fus X-Mailer: NETCOMplete v3.25, from NETCOM On-Line Communications, Inc. Several items here: 1: Assuming the weight and balance of the airframe is the same, then the canard projection from the fuselage should be the same, to provide the same amount of lift. This means the canard overall length will be longer by the amount that the fuselage is wider at that point. Since the load producing area is the same, the canard structure need not be stronger. 2: The wider fuselage is a new configuration airframe, and will probably weigh more, in particular forward, creating a new weight and balance situation. With more weight forward, the canard must furnish more lift. Think about the fuselage supported by the canard, and at the center of area of the wing, just like a scaffold plank on 2 ladders. The additional lift must be generated by higher takeoff and landing speeds, or additional canard area. 3: The COSY CLASSIC is 3.5" wider than the MK3 and the same width as the MKIV at the front seat. Due to many pilot and passenger comforts and added area of fuselage structure, the weight is 1168 lbs, and when empty has 37 lbs on the nose wheel when level. I started out with the drawing canard, but preferred a slower takeoff/landing speed. During cruise the elevators were down 3/8" at the trailing edge. About that time did the testing of C.G. range with the MKIV. After studying the test result, duing numerous calculations of weight and balance, and discussing with several gurus, I cut off the canard tips at the elevator ends, and added 3 inches to each end (6 inches total). It was an easy modification, with the plane out of service on 4 days including painting. This brought the speeds down to something more my liking. Very careful flight testing showed that deep stalls were not an issue. The elevators are now in trail at cruise. I feel that the canard could be made longer yet, but my conservative nature prevails. ------End forward message--------------------------- From: SBLANKDDS Date: Sun, 18 Jan 1998 11:06:56 EST Subject: Re: COZY: Lenght of Canard when widening the Fuse In a message dated 01-18-98 CDenk responded: << 1: Assuming the weight and balance of the airframe is the same, then the canard projection from the fuselage should be the same, to provide the same amount of lift. >> Not necessarily true. The Cozy claims a lifting body. Before just adding to the canard and possibly creating too much lift, testing needs to be done (like Nat did). There are very few "simple" changes to the airframe. If you change it, it becomes a new plane. it may be very similar to the old one, but maybe not............ If you widen the Fuse near the seatback only, then you change the curve of the fuselage side. If you widen it all the way up to the canard, then you will probably change the length and shape of the nose. How much can you do this before you change the drag and performance? Create a thorough test program with safety back ups before you fly, then fly it. (parachute and moving weight for example). Try not to change too many items at once. Then rename the bird, it won't be a Cozy any more. (maybe better?) Steve Blank - Cozy Mark IV #36 Date: Sun, 18 Jan 1998 21:49:13 -0500 From: David Domeier Subject: Re: Fwd: Re: COZY: Lenght of Cannard when widening the Fus Carl, re " Due to many pilot and passenger comforts and added area of fuselage structure, the weight is 1168 lbs, and when empty has 37 lbs on the nose wheel when level. I cut off the canard tips at the elevator ends, and added 3 inches to each end...The elevators are now in trail at cruise." I guess that's one way to skin a cat. Another way would have been to move the cg aft a bit. What you did was move the center of lift forward. At the moment (no pun intended) my airplane (MKIV) won't sit without nose ballast. When the radios and flight instruments go in later this spring that will help some but I think ballast will still be required. A slightly wider fuselange probably will not noticably effect the flying characteristics of these airplanes. Nat did it with the first Cozy and besided that, the canards have been getting shorter anyhow to move the center of lift and cg limit slightly aft. A better idea might be to go on a diet if the airplane isn't wide enough as is. You could carry more fuel, be more comfortable and maybe live longer. dd From: cdenk@ix.netcom.com Date: Sun, 18 Jan 1998 22:00:25 -0600 (CST) Subject: Re: Fwd: Re: COZY: Lenght of Cannard when widening the Fus David Domeier writes How do propose moving CG aft the aircraft has 550 hours? This is the 2nd COSY flying and the first was only a month or so earlier, was surprised that it was nose heavy, but there was no previous experience, otherwise I would have mounted the engine further aft. You seem to be concerned for safety, maybe I could remove the 2 KX155's, ADF and GPS. The plane was complete when the weight and balance was known. As for diet, I'm 72 inches, 185 lbs, and have been that for atleast 10 years, after a peak of 208 lbs. Minimum front seat weight is placarded at 180 lbs. Whats carrying more fuel got to do with it. Normal crosscountry flights start with full tanks, plan on 1 hours reserve, maybe a little less if weather excellent, and going into into familiar area. So need to be within C.G. limits both full and empty. From: lschuler@cellular.uscc.com Date: Mon, 19 Jan 98 08:51:18 -0600 Subject: Re: COZY: Lenght of Cannard when widening the Fus Pine Pienaar wrote: >snip >I have seen lots of posting where people say they are or want to widen the >fuselage. >I also konw it possible to only widen the seatback, but how does the >lenght of the cannard and that of the center spar, wings and so-on relate >if the fus is made 2" wider from tip to end. >I discused this with James Newman of Infinity who's oppinion I trust. But >would like to get some more views on the subject. If your intention is to widen the fuselage by 2", simply add 1" to {{EVERYTHING}} on either side of BL-0 (center). This will affect the width of the seats, bulkheads fuselage, center section spar and canard; BUT, only between the fuselage sides. ALL future BL measurements will require adjustment by 1" at every step of the way. Not difficult, but absolutely manadatory that you "remember" to do this as you go.... It bites when you don't. The canard and the wing's tip-to-tip measurement will ultimately be increased by 2"; however, the wetted canard and wing area will remain unchanged. This is because you are only adding to the canard and spar internal to the fuselage, not external. Some special consideration may be needed if you are going with plans main gear. Make sure to adjust the hard point layups (now 1" more inboard of the fuselage sides than per plans) to keep the mounting point width the same. The main gear bulkheads should 'probably' be widened at the fuselage sides rather than at BL-0. This will take care of the mounting point shift from the sides as well as the total width. Also, keep in mind that with increased length of the canard and spar, even if it is just inside the fuselage, changes the moment-arm of lifting surfaces. You should strongly consider a stress analysis. Only other consideration that comes to mind at the moment is the small increase in lifting body of the fuselage. Mostly just relative to deep stall and max aft CG location of your new non-Cozy aircraft. Larry Schuler MK-IV plans #500 lschuler@cellular.uscc.com From: DFinn7971 Date: Tue, 20 Jan 1998 10:06:43 EST Subject: Re: COZY: Lenght of Cannard when widening the Fus In a message dated 98-01-20 07:37:24 EST, lschuler@cellular.uscc.com writes: << If your intention is to widen the fuselage by 2", simply add 1" to {{EVERYTHING}} on either side of BL-0 (center). >> I agree with Larry as far as how to widen the fuselage. A second ocnsideration would relate to the canopy and turtleback. You could widen the turtleback easily but you should give some thought about how to handle the stock canopy. It would have to be mated to the turtleback. Possibilities would be to form your own canopy or cut it down the center and add a fiberglass spacer. As a question for Jeff Russell, how did you do it with the Aerocanard? Dick Finn From: "Johnson, Phillip" Subject: Re: COZY: Lenght of Cannard when widening the Fus Date: Tue, 20 Jan 1998 13:17:03 -0500 There has been much discussion on the subject of making a longer canard when widening the fuselage. Most of the recommendations are to add the same dimension to the wing & canard span as is added to the fuselage width. This does indeed seem logical at first sight, however the fuselage is a lifting body starting at FS -6 and extends to approximately FS 165 at the prop. Most aerofoils have their centre of lift at about 25% chord which would place the body lift centre at approximately FS 80 twenty inches ahead of the mean CofG (widening the body generally pushes the nose position forward so this location would also move forward under these conditions). Changing the body lift at FS 80 will impact the weight and balance envelope similar to that of a longer canard. In practice the centre of lift for the fuselage may not be as far forwards as in a classical aerofoil which may mitigate the impact of fuselage widening and the additional downward pitching moment caused by the more significant body size may also require more lift to be available at the front end. I am not one to discourage experimentation, just be cautious and aware of this possibility when test flying, i.e. start the test flying in the forward part of the CofG envelope. Good Luck ---------------------------------------------------------------------- Phillip Johnson Tel (613) 253 2229 (H) Ottawa, (613) 599 3289 ext. 441 or 232 Ontario, Cozy MKIV RG #30 Canada. Subaru EG33 ----------------------------------------------------------------------- From: cdenk@ix.netcom.com Date: Tue, 20 Jan 1998 15:29:27 -0600 (CST) Subject: Re: COZY: Lenght of Cannard when widening the Fus Remember when widening the fuselage, the plexiglass bubble probably must be bigger. From: cdenk@ix.netcom.com Date: Tue, 20 Jan 1998 15:40:36 -0600 (CST) Subject: Re: COZY: Lenght of Cannard when widening the Fus On 01/19/98 08:51:18 you wrote: > > > >Pine Pienaar wrote: >>snip >>I have seen lots of posting where people say they are or want to widen the >>fuselage. > >>I also konw it possible to only widen the seatback, but how does the >>lenght of the cannard and that of the center spar, wings and so-on relate >>if the fus is made 2" wider from tip to end. > >>I discused this with James Newman of Infinity who's oppinion I trust. But >>would like to get some more views on the subject. > > >If your intention is to widen the fuselage by 2", simply add 1" to >{{EVERYTHING}} on either side of BL-0 (center). This will affect the width >of the seats, bulkheads fuselage, center section spar and canard; BUT, only >between the fuselage sides. > >ALL future BL measurements will require adjustment by 1" at every step of >the way. Not difficult, but absolutely manadatory that you "remember" to >do this as you go.... It bites when you don't. > >The canard and the wing's tip-to-tip measurement will ultimately be >increased by 2"; however, the wetted canard and wing area will remain >unchanged. This is because you are only adding to the canard and spar >internal to the fuselage, not external. > >Some special consideration may be needed if you are going with plans main >gear. Make sure to adjust the hard point layups (now 1" more inboard of >the fuselage sides than per plans) to keep the mounting point width the >same. The main gear bulkheads should 'probably' be widened at the >fuselage sides rather than at BL-0. This will take care of the mounting >point shift from the sides as well as the total width. > >Also, keep in mind that with increased length of the canard and spar, even >if it is just inside the fuselage, changes the moment-arm of lifting >surfaces. You should strongly consider a stress analysis. > >Only other consideration that comes to mind at the moment is the small >increase in lifting body of the fuselage. Mostly just relative to deep >stall and max aft CG location of your new non-Cozy aircraft. > > I would suggest also widening the instrument panel. Also tightening the radius on the bubble/turtleback area gives more clearance for headsets. With the wider seat back, ones cranium will be outward with the neck/back straight, this needs accounting for.