Bean Counter Posted June 1, 2008 Posted June 1, 2008 I have been researching the Cozy Mk IV for a while and will likely buy a set of plans within the week. I have some questions I need answered before I do, so I hope you folks can help me. 1. Aerocad's website mentions a canopy with more headroom (2 inches in height and 2 inches in width) for the front seats. Does the standard Cozy MK IV canopy lack in this area? How tall does a pilot have to be before needing the extra height? 2. I would prefer to build from plans rather than a kit (hence the Cozy). I would like to buy some pre-fab parts to speed the process, however, but I'd need to be thrifty about the cost (hence my screen name ). If you were going to recommend some pre-fab components to go on a Cozy Mk IV based on the most "bang for the buck" (build time saved per dollar spent) what would be the top priorities? 3. What is the limiting factor for the 220 mph top speed? When I see planes like the Berkut going much faster, I wondered what limits the Cozy. If more horsepower were available at the same installed weight, what would have to be modified or redesigned to cruise as fast as say, a new mooney. Thanks in advance! Quote
TMann Posted June 1, 2008 Posted June 1, 2008 1. Don't worry about the headroom on the Cozy just yet. Everything is on the table when you're working with conposites. There's nothing saying you can't buy the Aerocanard canopy and fit it to your fuselage. You wouldn't be the first. 2. Best source for prebuilt parts - The Cozy Girls. 3. Huh......220 is too slow? The Berkut has Carbon Fiber wing skins and wing spar caps. Add a couple grand to your building costs to get beyond 220. Quote T Mann - Loooong-EZ/20B Infinity R/G Chpts 18 Velocity/RG N951TM Mann's Airplane Factory We add rocket's to everything! 4, 5, 6, 7, 8. 9, 10, 14, 19, 20 Done
Lynn Erickson Posted June 2, 2008 Posted June 2, 2008 3. What is the limiting factor for the 220 mph top speed? When I see planes like the Berkut going much faster, I wondered what limits the Cozy. If more horsepower were available at the same installed weight, what would have to be modified or redesigned to cruise as fast as say, a new mooney. Thanks in advance! thats the aircrafts designed VNE. the Berkut is all carbon and has a higher VNE there are modified cozy's going faster but may be taking a chance on going over VNE. just adding carbon to the structure might help but a redesign should be done by someone with that kind of knowledge. it will also need a lot more HP. Quote Evolultion Eze RG -a two place side by side-200 Knots on 200 HP. A&P / pilot for over 30 years
mplafleur Posted June 3, 2008 Posted June 3, 2008 thats the aircrafts designed VNE. the Berkut is all carbon and has a higher VNE there are modified cozy's going faster but may be taking a chance on going over VNE. just adding carbon to the structure might help but a redesign should be done by someone with that kind of knowledge. it will also need a lot more HP. That certainly wasn't the designed VNE as I'm sure there wasn't a lot of design and analysis. This was the calculated VNE during the testing phase of the aircraft. Quote Mike LaFLeur - Cozy MkIV #1155N68ML
Lynn Erickson Posted June 3, 2008 Posted June 3, 2008 That certainly wasn't the designed VNE as I'm sure there wasn't a lot of design and analysis. This was the calculated VNE during the testing phase of the aircraft.220 MPH is the designed red line for the Long ez thats where Nat got that design speed. since it is just a long ez wing with 12" added to the inboard section of each wing and the same canard Quote Evolultion Eze RG -a two place side by side-200 Knots on 200 HP. A&P / pilot for over 30 years
Waiter Posted June 3, 2008 Posted June 3, 2008 What is the limiting factor for the 220 mph top speed? Flight Testing is the limiting factor. (220 mph = 190 kts.) Regardless of what the design speed is, the aircraft must be flight tested and placarded accordingly. As a general rule of thumb, take the highest flutter speed achieved during testing, and multiply it by 0.85. This is the placarded Vne. If the maximum speed during flutter testing was 160 kts, then the aircraft needs to be placarded with a Vne of 136 kts (160 x .85 = 136) When I tested my LongEZ, The highest flutter test speed I reached was 260 kts, I red lined my aircraft at 221 kts. (260 x .85 = 221) Take a look at my web site and you can download a publication put out by the FAA: AC 90-89A Amateur Built aircraft and ultralite flight testing handbook. goto: http://www.iflyez.com/Placards.shtml Scroll down to the bottom. Waiter Quote F16 performance on a Piper Cub budget LongEZ, 160hp, MT CS Prop, Downdraft cooling, Full retract visit: www.iflyez.com
mplafleur Posted June 3, 2008 Posted June 3, 2008 220 MPH is the designed red line for the Long ez thats where Nat got that design speed. since it is just a long ez wing with 12" added to the inboard section of each wing and the same canardDesigned red line? What kind of calculations were used to come up with this number? I don't think it would be possible. I don't even think Marc could do it. Part of it relies too much on construction materials and technique. It could only be demonstrated. (Thank you Waiter) Quote Mike LaFLeur - Cozy MkIV #1155N68ML
Lynn Erickson Posted June 3, 2008 Posted June 3, 2008 Designed red line? What kind of calculations were used to come up with this number? I don't think it would be possible. I don't even think Marc could do it. Part of it relies too much on construction materials and technique. It could only be demonstrated. (Thank you Waiter) maybe it was tested red line speed but you might want to ask Burt Rutan that question as he is the one that printed it in the long ez owner's manual. in the manual it is listed as redline speed - demonstrated speed 220 MPH. it is also on the cozy IV flight envelope drawings - VNE 220 MPH Quote Evolultion Eze RG -a two place side by side-200 Knots on 200 HP. A&P / pilot for over 30 years
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