As Doedo wrote, I did enjoy flying his and Gail's Jungmann as well as George Becker's newly restored one back to back last weekend. My thanks to all three of them for being so generous with their airplanes. I certainly hope to reciprocate the favor soon.
Other than my own, these are the first O-320 powered Jungmanns I've flown and for me it was very instructive. At very nearly the same weights, there was a noticeable difference in takeoff and climb performance with Doedo and Gail's the better performer in climb yielding a slight edge to George's airplane in cruise. The major performance difference between the two is certainly in the props. I didn't get the exact specs but George's prop is a bit longer and I'd guess two inches greater in pitch. Both climbed much better than my slightly heavier Lycoming Jungmann did when equipped with a metal Sensenich 74DM 58 but they also cruised much slower at a similar power setting....but then we don't own a Bucker for cruise performance do we?
After flying these two aircraft, Pat Quinn's and a couple in the Hickman fleet, I'm certain that despite the greater efficiency, a metal prop of any pitch does not enhance the flying qualities of a Lycoming powered Jungmann. None of these aircraft exhibited any of the gyroscopic effect that mine did when fitted with the metal prop and all are much smoother and quieter in flight not to mention better balanced and much safer for aerobatics without all that weight on the nose. For general flying I'd say that there isn't much performance difference between these O-320 powered aircraft and the other Buckers I've flown powered by O-360s. The difference in this case could be that of a new, strong 160 plus hp. engine vs. a 180 hp. engine with a little time on it. I'm sure the somewhat lighter engine installed weight helps as well. For those who don't find the aesthetics of a flat-engined Jungmann objectionable, I'm convinced that an O-320 on a light airframe is a great affordable combination.
The two aircraft I flew at Blakesburg are simultaneously very similar and quite different from one another. Both of their Lycomings are newly built. Both are high-compression O-320 powered and both are similar in weight at around 950 lbs. empty. The Schipper's engine is equipped for aerobatics with inverted oil, Ellison throttle body and an Aymar-Demuth prop optimized for climb. George's carburetted engine is not intended for anything but limited aerobatics although when he built it he did increase the compression a bit, added a "hotter" cam and four into two exhaust. His prop is a Ted Hendrickson that he happened to have on hand but it works quite well.
George's yellow Jungmann is simply beautiful. The huge amount of skill and attention to detail he lavished on this aircraft is very obvious both on the ground and in flight. With only about 60 hours, it is by a large margin the newest restoration I've ever flown and certainly one of the best. Particularly notable is the almost total lack of control friction. The controls are so light it is almost disconcerting. It nearly feels as though nothing is connected. To the uninitiated I normally describe the feel of a Bucker's controls as being "like a long stick in about three inches of sand." I'd describe George's Jungmann's as the same stick in a bucket of water......if that's possible.
Doedo has done all the aerobatic maneuvers in both aircraft and although I'm no expert, asked me for my input on flying qualities independent of his. We didn't have parachutes so no aerobatics were done but during basic maneuvering and stability tests some differences between the two airplane were notable. As one would expect from such a comprehensive rebuild, overall George's airplane is simply crisper feeling, lighter and better "hooked up" than the Schipper's which itself is a delightful airplane. It is also much more neutral in all axises. It could just be me but I found that I needed to devote a lot more attention to fly George's Jungmann well. My only gripe would be that it seems slight gusts or inattentiveness caused the airplane to deviate a little too easily from coordinated flight. This made the workload to fly the airplane well to increase dramatically and for me, it somewhat diminished the enjoyment of flying an otherwise excellent airplane. I actually found that only two approaches really worked - strict attention or relying on pure Zen.......but it's hard to maintain that state in traffic.
Generally, this along with the somewhat more appropriate prop pitch makes the Schipper's airplane a bit more enjoyable to fly. The difference in props is particularly apparent when accelerating from very slow speed. I'm also sure that it would be noticeable at slow speeds during aerobatics. Also notable in that regime is the slightly off-set thrust line in George's engine mount versus the Schipper's which is dead straight. There seems to be a bit more tendency for the airplane to torque off a straight line at high power and low speed and coupled with the somewhat slower acceleration, it requires more attention to hold a line.
The largest handling difference between the two though is in the yaw axis when a roll was initiated. Doedo's seemed much more predictable and much less prone to excursions with rudder input to coordinate for adverse yaw. During the same maneuvers George's rudder seems to over control with a slight amount of reversal that wasn't apparent in any other Jungmann I've flown. I had wanted to compare the weight and balance paperwork of the two but somehow during the course of the weekend they weren't on the ground long enough to do so. I suspect that the C.G. on George's airplane is somewhat further aft than on Doedo's. Possibly a bit too far aft. Also contributing to this could be that George has yet to fit a rudder gap seal. I've never flown another one without it so I wouldn't know.
I am also beginning to suspect that Jungmann handling is influenced by the amount of vertical area on the airframe forward of the C.G. It seems to me that Tigre powered aircraft I've flown, the Schipper's and possibly (I haven't flown them) Brian Karli's as well as the early Menear aircraft with deeper cowls seem to respond much more predictably in well coordinated turns and tend to penalize the pilot more predictably for poor coordination. Put another way, the sleeker the cowl shape, the less the airplane tends to "carve" into a turn and the more the nose tends to drop when approaching knife edge. George's airplane is fitted with the Mike Meloche Lycoming conversion and is very tightly cowled with very little chin area. Once again, I'd like to compare notes with others who have more experience with the various configurations to flesh out this thesis.
Both of these airplanes are great and despite the subtle differences fly as only Buckers do. Within that context it is pretty hard to describe or to complain about subtle differences. With a new cover job and engine installation but little else changed, the Schipper's is perhaps a little bit further developed than George's but I'm sure that will change when he has the time to do the final "tweeking." They both serve to illustrate that sensible modifications to improve reliability don't have to be made at the expense of performance or delightful flying qualities.
Alan
Other than my own, these are the first O-320 powered Jungmanns I've flown and for me it was very instructive. At very nearly the same weights, there was a noticeable difference in takeoff and climb performance with Doedo and Gail's the better performer in climb yielding a slight edge to George's airplane in cruise. The major performance difference between the two is certainly in the props. I didn't get the exact specs but George's prop is a bit longer and I'd guess two inches greater in pitch. Both climbed much better than my slightly heavier Lycoming Jungmann did when equipped with a metal Sensenich 74DM 58 but they also cruised much slower at a similar power setting....but then we don't own a Bucker for cruise performance do we?
After flying these two aircraft, Pat Quinn's and a couple in the Hickman fleet, I'm certain that despite the greater efficiency, a metal prop of any pitch does not enhance the flying qualities of a Lycoming powered Jungmann. None of these aircraft exhibited any of the gyroscopic effect that mine did when fitted with the metal prop and all are much smoother and quieter in flight not to mention better balanced and much safer for aerobatics without all that weight on the nose. For general flying I'd say that there isn't much performance difference between these O-320 powered aircraft and the other Buckers I've flown powered by O-360s. The difference in this case could be that of a new, strong 160 plus hp. engine vs. a 180 hp. engine with a little time on it. I'm sure the somewhat lighter engine installed weight helps as well. For those who don't find the aesthetics of a flat-engined Jungmann objectionable, I'm convinced that an O-320 on a light airframe is a great affordable combination.
The two aircraft I flew at Blakesburg are simultaneously very similar and quite different from one another. Both of their Lycomings are newly built. Both are high-compression O-320 powered and both are similar in weight at around 950 lbs. empty. The Schipper's engine is equipped for aerobatics with inverted oil, Ellison throttle body and an Aymar-Demuth prop optimized for climb. George's carburetted engine is not intended for anything but limited aerobatics although when he built it he did increase the compression a bit, added a "hotter" cam and four into two exhaust. His prop is a Ted Hendrickson that he happened to have on hand but it works quite well.
George's yellow Jungmann is simply beautiful. The huge amount of skill and attention to detail he lavished on this aircraft is very obvious both on the ground and in flight. With only about 60 hours, it is by a large margin the newest restoration I've ever flown and certainly one of the best. Particularly notable is the almost total lack of control friction. The controls are so light it is almost disconcerting. It nearly feels as though nothing is connected. To the uninitiated I normally describe the feel of a Bucker's controls as being "like a long stick in about three inches of sand." I'd describe George's Jungmann's as the same stick in a bucket of water......if that's possible.
Doedo has done all the aerobatic maneuvers in both aircraft and although I'm no expert, asked me for my input on flying qualities independent of his. We didn't have parachutes so no aerobatics were done but during basic maneuvering and stability tests some differences between the two airplane were notable. As one would expect from such a comprehensive rebuild, overall George's airplane is simply crisper feeling, lighter and better "hooked up" than the Schipper's which itself is a delightful airplane. It is also much more neutral in all axises. It could just be me but I found that I needed to devote a lot more attention to fly George's Jungmann well. My only gripe would be that it seems slight gusts or inattentiveness caused the airplane to deviate a little too easily from coordinated flight. This made the workload to fly the airplane well to increase dramatically and for me, it somewhat diminished the enjoyment of flying an otherwise excellent airplane. I actually found that only two approaches really worked - strict attention or relying on pure Zen.......but it's hard to maintain that state in traffic.
Generally, this along with the somewhat more appropriate prop pitch makes the Schipper's airplane a bit more enjoyable to fly. The difference in props is particularly apparent when accelerating from very slow speed. I'm also sure that it would be noticeable at slow speeds during aerobatics. Also notable in that regime is the slightly off-set thrust line in George's engine mount versus the Schipper's which is dead straight. There seems to be a bit more tendency for the airplane to torque off a straight line at high power and low speed and coupled with the somewhat slower acceleration, it requires more attention to hold a line.
The largest handling difference between the two though is in the yaw axis when a roll was initiated. Doedo's seemed much more predictable and much less prone to excursions with rudder input to coordinate for adverse yaw. During the same maneuvers George's rudder seems to over control with a slight amount of reversal that wasn't apparent in any other Jungmann I've flown. I had wanted to compare the weight and balance paperwork of the two but somehow during the course of the weekend they weren't on the ground long enough to do so. I suspect that the C.G. on George's airplane is somewhat further aft than on Doedo's. Possibly a bit too far aft. Also contributing to this could be that George has yet to fit a rudder gap seal. I've never flown another one without it so I wouldn't know.
I am also beginning to suspect that Jungmann handling is influenced by the amount of vertical area on the airframe forward of the C.G. It seems to me that Tigre powered aircraft I've flown, the Schipper's and possibly (I haven't flown them) Brian Karli's as well as the early Menear aircraft with deeper cowls seem to respond much more predictably in well coordinated turns and tend to penalize the pilot more predictably for poor coordination. Put another way, the sleeker the cowl shape, the less the airplane tends to "carve" into a turn and the more the nose tends to drop when approaching knife edge. George's airplane is fitted with the Mike Meloche Lycoming conversion and is very tightly cowled with very little chin area. Once again, I'd like to compare notes with others who have more experience with the various configurations to flesh out this thesis.
Both of these airplanes are great and despite the subtle differences fly as only Buckers do. Within that context it is pretty hard to describe or to complain about subtle differences. With a new cover job and engine installation but little else changed, the Schipper's is perhaps a little bit further developed than George's but I'm sure that will change when he has the time to do the final "tweeking." They both serve to illustrate that sensible modifications to improve reliability don't have to be made at the expense of performance or delightful flying qualities.
Alan