Text and Photos by Budd Davisson, Private Pilot, August 1970
|Rereading this is an interesting piece of historical review for me. At the time, I'd only been doing the magazine thing for less than two years, my Nikon wasn't even a year old and I'd done maybe four pilot reports (eventually to swell to something like 400-500). My only credentials were that I was becoming a fairly experienced aerobatic flight instructor (Citabrias). Still, Bill Thomas saw fit to toss me into his Jungmiesters every chance he got and, in so doing, introduced me to the world of serious aerobatics. For that, and many other things, I can't thank Bill enough. I hope, in the long run, I will have affected as many lives in as positive a manner as he has.|
I STUFFED THE STICK forward into the corner, bottoming opposite rudder at the same time. The nose slewed left and dropped to about 45 degrees, where it hesitated for the briefest instant-but the hesitation had the quietness of a lull before a storm ...it spoke of things to come. Suddenly the nose curled under, the world zipped around in an arc and, as I saw the horizon flash by inverted, I heard a voice-mine-saying, "sonova ... !" out loud. The whole maneuver occurred in micro-seconds, but when you're pulling two negative Gs, inverted, in an open cockpit, you can recall the entire sequence as if your mind's eye was seeing it in stop action photography. An outside snaproll is something wild!
I was riding around behind four wings with an aileron apiece, and 220 of the firebreathingest horses you've ever seen. This was Jungmeister 1970. Aside from the 220 horses, the 1970 model is the same as the 1969 model, which was the same as the 1935 model. When you've got something as good as a Bucker Jungmeister, there just isn't a heck of a lot that you can improve on. The Jungmeister is known the world over as being one of the best in its field-the field of ballet, aerial ballet, as practiced by Bevo Howard and Hal Krier and hundreds before them. From its very beginning, as a Luftwaffe akro trainer in pre-war Germany, the Bu-133D was recognized as the absolute top of the acrobatic totem pole, and when it went out of production during WWII its value kept rising, as there was nothing that could replace it in the world of inside-out flying.
Aerobatics has always had a large following in Europe, but in the U.S.A. we were slow to develop the sport. The 1960s saw a tremendous awakening of sport flying in general and aerobatics in particular-two of the big three airplane builders introduced limited akro ships, and Champion was making almost nothing but. Where there are beginners there will soon be experts, but there was, and is, nothing being produced in America that's a suitable mount for the serious akro-nut. If he didn't mind rolling his own he could build a Pitts, or modify a Chipmunk, but outside of the superb, but rare, Czech Zlin, there was no such thing as a production acrobatic bird for the semi-pro, or the talented amateur.
1969 saw the rebirth of the Bucker. This wasn't a modified version, or a restored antique ... this was a 1935 Bucker Bu-133D Jungmeister built in 1969. Where the idea of reproducing Buckers originally incubated is a moot point because everybody who flies upside down has thought the Jungmeister should still be in production. but it took the late Jack Canary to put the wheels in motion. Carl Bucker was still alive, and the factory drawings were still in existence, so Canary just found some businessmen to put up the capital, and some craftsmen capable of building a new antique. The Thomas brothers were the boys who ended up importing the bird, and the craft shop of Wolf and Hirth in Germany are producing them. It must be emphasized that the 1969/70 Jungmeister is built exactly to the original factory drawings, with modern, stronger materials substituted where possible.
The weakest point of any biplane's performance is in the vertical plane, where the drag shows up the most. The Jungmeister is especially dirty because the entire thing is laced together with streamlined wire, rather than struts. Even the ailerons are interconnected, top to bottom, with wire. There is so much junk hanging out that it just has to slow down as the nose comes up, and with the original Siemens 160-hp engine, it really didn't have much to pull it uphill. There are two possible ways to overcome the high drag problem; you can clean up the airframe, or you can hang more horses up front. Cleaning up a biplane is an endless task, so the 1970 Bucker solves the problem by stuffing as many ponies as it can hold forward of the firewall.
This last model Jungmeister uses a six cylinder opposed Franklin, that punches out 220 horses. A number of professional akronauts have hung flat engines on their Jungmeisters, but the resulting cowl shape is usually ten feet to the right of ugly. With it's humped back, canted gear, and formless tail, the Jungmeister borders on the aesthetically obnoxious as it is, and when you try to fair a flat engine into a round firewall, it makes it look like somebody slammed a window on its beak. In an effort to avoid cowling problems and preserve the old-timey, beautiful ugliness of the bird, the decision was made to stay with a round cowl, and make use of the space as well as possible. A flat, pointed cowl undoubtedly would have cut some drag, but it would have had purists around the world retching over the rail.
The engine itself is a Franklin 6A-350-Cl (for those of you who dig numbers) but to the rest of us, it's a flat six, fuel injected, and uses a dual sump system for oil. The oil pump has an arm sticking out of it with a big weight on the end, so that the weight moves the arm as soon as the G forces go negative. This arm changes the pump's valving so that it scavenges from the small sump mounted on the top of the crankcase. The fuel arrives via a flop tube in the tank, which can be selected by a gigantic, diesel-looking lever in the cockpit. To eliminate any possibility of fuel starvation because of a kink in the flop tube, this lever allows you to choose a normal fuel pick up, so all takeoffs and landings are made in this position.
The mag location on the engine required making the firewall V-shaped for clearance. It looked like the entire firewall might have been shoved a smidgen aft, but it's difficult to tell because I really haven't seen that many naked Jungmeisters. It would figure that the Franklin would have to be mounted aft because its CG is naturally a little forward of the Siemens'.
The lower part of the cowl area is occupied by the airbox, but theupper space is vacant. The whole thing is surrounded by a tubing frame to support the fiberglass cowl. The new cowl is built in two halves, top and bottom, and as originally designed was located on the framework by locating pins. The only thing holding it on was the cowl latches and the pins sticking through. On one of the first flights Bill Thomas found smoke boiling back in his face and he debated whether or not to ride the silk elevator down. He made a quick landing at Curtiss Pitts' place and found that the air pressure had ballooned the cowl enough to disengage the locating pins, and the cowl had slid forward into the wooden fan, chewing huge chunks out of the back of the prop. Pitts loaned him a prop from one of his little Specials, and that's the prop it had on it when I flew it. As soon as Bill got the wounded bird home, he promptly ran machine bolts through both sides of the cowl and the framework to make sure it stayed put.
The only cockpit change I could find in this Bucker as compared to the old Siemens powered job, was that it had a mixture control, and there were two skid-balls mounted in the middle of the panel . . . one was upside down, but which one it is depends on which direction your head is pointed at that moment. The first time I sat in a Jungmeister I thought the stick with the bent rod on top of it was funny looking, but this time I noticed that it was probably a way of adjusting the position of the stick ball to fit each pilot's arm length. Somehow I missed that last time. Sorry mister Bucker.
Since the seat isn't adjustable, I had Bill scout up a cushion 'so that I could see what I was doing on the runway ...I found later that this was a mistake. The correct position to fly a Jungmeister from is with the top edge of the forward cockpit railing about forehead high, when on the ground. If you sit any higher, your head sticks out into the slipstream during outside maneuvers and you can't see a thing. Also, when sitting up higher, you really don't gain enough visibility to make it worth it. You'd have to be standing up in the seat to see over the nose, and the doors don't come up high enough to cut off any vision, so you might as well sit low. I know this now, but I didn't the first time.
One thing can be said for Bill Thomas and his Jungmeisters: They certainly do have the gear to strap you in. Besides all the miles of webbing on the back pack chute, there is the usual seat belt, acrotch strap, another seat belt, and the shoulder harness. Even the rudders have straps on them to keep your feet from slipping off. (I've always found rudder straps to be redundant, because when I'm charging around hanging from my seat belt I stand up on the rudders, wedging myself between the shoulder harness and the pedals. This could be part of the reason I have about as much finesse as a Rhesus monkey when I fly inverted.) It takes several minutes to get strapped in, but once it's done, baby you are definitely in! It's one of the most secure feelings I've ever had in this type of machine-no matter what I did later on, I never noticed any shifting or sliding around. The whole shooting match is disconnected with a yank on the common buckle, in case you decide you'd rather be elsewhere in a hurry.
The Jungmeister doesn't have any electrical system of its own, so an APU is needed to fire it up. Bill's APU is the original battery cart-two batteries on a lawn mower chassis. He cautioned me not to pump the throttle or prime it, because if it got much fuel up into the cylinders the compression was too high for the batteries to overcome. Later, we started it by jumping the battery of my Hertz U-drive-it APU, and it kicked right off, so I doubt if the starter is the problem, I think it's the aux power package.
The engine caught on the first blade, and the first thing I noticed was how much smoother and quieter it was than the Siemens. even on the ground. I handled the throttle like a dynamite plunger and taxied out gingerly. The tail wheel has a lock and unlock position, which in this case means that in the unlock position it's full swiveling, and in the locked position, it's steerable . . . and how! Bill doesn't think the tail wheel is sensitive, but I do. I have to taxi a Bucker like I'm tap dancing on eggs or I weave all over the place. Of course, you have to weave anyway or you'll taxi over a hangar or something ... it's stone blind in about a 30 degree arc over the nose.
Since the airplane is so tiny, and the engine is anything but, I eased the power in slowly on takeoff. I meant to move it fast enough to induce a little torque yaw, just to test it, but either it doesn't yaw much, or I was moving the throttle too slowly, because it tracked straight as the painted stripe with only an occasional tap on the rudder bar to keep it straight. I brought the power back to a reasonable sounding 2500-rpm and held what looked like a normal climb attitude, which turned out to be about 85-mph. I didn't really feel like I had been booted in the tail, or that I was skyrocketing up, but when I was half way down the runway I peeked down at the airport and it was one hell of a long way down. A 150 had taken off quite a way ahead of me, and when I turned crosswind, I saw him in my two o'clock position, still on crosswind, and so far below me that I could barely tell it was a I 50. I had a good solid 2,500 feet when I crossed the end of the runway-it was like somebody had punched a button and lowered the air-port.
As I leveled out at 3,000 and the speed built up, I could feel the slipstream nipping at my helmeted head. The Florida sun was warm on my face and the air was crisp. I was garbed in tee-shirt and helmet, but nevertheless the effect was one of looking for those heavily protected observation balloons, stretching my neck to watch for Fokkers and Pfalzs.
It was intoxicating, so 1 twitched my hand and put the everglades where the sky had been and vice versa. Such a wonderful Walter Mitty machine! There is no way I can possibly describe the feelings of freedom, of release from the mechanical limitations of an airplane, andthe merging of man and machine. To do aerobatics in something like a Bucker, or a Zlin, or a Pitts, is a world unto itself. It bears little or no resemblance to flitting around in an Aerobat or wrestling with a Citabria. The motions you put the airplane through aren't maneuvers, they're thoughts, translated to arcs and circles and whatever your mind and body sees or feels. You don't worry about falling out of a roll, you don't struggle to hold altitude. You just make a wish and the airplane fulfills it. Before I got serious and started really evaluating the 220 Jungmeister, I just let my mind run wild. and the airplane followed. I luxuriated in slow, slow rolls—so slow that they were many small segments of different attitudes pasted together with no seams showing. I astonished myself with lightning fast snap-rolls, sometimes one, sometimes two, but more often one-and-a-half into diving inverted flight, ending up with a neck stretching outside push, feeling like a flea on a bowling ball, going back up into level flight. It was effortless. So fantastically effortless, and fluid. The man and machine ceased to exist as separate entities, leaving only the feeling of unlimited flight.
I always get such a kick out of the way a Bucker snaps. It's absolutely unbelievable! The double swept wings mean that as soon as the rudder is smashed down the advancing wings pick up lift, throwing you around fast. If you use ailerons the effect is tripled. The roll rate in a snap has to be more than 360 degrees a second-by using full aileron into the snap. the horizon is already coming around right side up again before you're even ready to start. The entries are so clean and predictable that you can start and stop a snap anywhere. I was doing them inverted to inverted, going straight up, straight down, and anywhere I felt like it. It got so that whenever I ran out of maneuvers to try for a second, I'd snap-roll just to have something to do.
In normal flight, I wasn't conscious of the engine, and missed having its sound to judge power changes by. It is extremely quiet, the slipstream producing much more noise than the exhaust itself. The old Siemens was always there, rattling and shaking to let you know when you'd better ease off the throttle, but the Franklin is smoother and gentler.
The engine swap did nothing at all to change the fantastic handling characteristics of the Bucker. The controls are light, stick throw very short, and response immediate. The four ailerons and short wings make it an absolute joy in rolling maneuvers, and the slotted elevator makes it doubly effective whether pushing or pulling.
I was anxious to see how much difference the extra 60 horses would make, so I experimented in trying to find the best rate-of-climb speed. After some messing around I decided it moved up best at around 77-mph, which gave in excess of 2,000-fpm at 3,000 feet. It might climb better with the original prop, as this prop was four inches shorter than original equipment and was pitched for a Pitts.
The 220 ponies make the Jungmeister a whole new airplane when you point its nose up after a maneuver. Coming out of a loop or anything else with a little excess airspeed, the rate of climb goes past 3,000-fpm as soon as the nose passes the horizon, and the needle stays there for a long long time before all those wires hanging out start to slow it down. The Siemens powered bird would lose air-speed even in a loop, but the 220 job felt almost like a monoplane.
I never did get a full vertical roll out of the old Jungmeister, but I could do it easily with the 220 dragging me up. I'd dive it to near red line (it doesn't take much of adive if you use power), get a four G pull up, put my wing tip on the beach, and keep rolling until I saw the beach again. I was frankly amazed. This had been the Jungmeister's Achilles' heel, only now it was wearing combat boots to protect it.
Something should be mentioned about G forces and Jungmeisters. I'm not the world's most G-resistant pilot, at all. As a matter of fact, things start getting a little fuzzy at around 3.5 when I'm in the back of a Citabria. But in a Jungmeister you're sitting almost directly on the CG, so there is no moment arm to multiply the G force and make you pull more than your share. I worked the Jungmeister around 4.5 to 5.5 consistently, and went to minus 4, but I wasn't even aware of it. The absence of tremendous G forces alone is enough to make aerobatics in this bird a whole new experience.
Inverted flight and outside maneuvers get a whale of a boost from all that new power. A couple of times I hit full power as I went inverted, nose high, and found myself climbing at almost 1,000-fpm ON MY BACK! At 160-mph, it takes a good healthy four G push to make it over the top outside, but you can tell that it's brute force pulling you over and not pure inertia.
In a Citabria I gauge how long I've been flying by how limp my right arm feels, but in the Bucker I just kept watching the float in the fuel gauge. When I saw it get down to the quarter mark, I'd head home, but only because the airplane was out of gas ... I still had plenty of arm left.
All through the first hour in the new breed Jungmeister, I kept feeling like straps were slipping, as I'd constantly keep tightening them. As I broke out of my power approach, I suddenly realized that the straps hadn't been slipping, I'd been shrinking. Under the pressure of five Gs the seat cushion had packed down, and now as I was ready to land, I found the top of the panel even with the top of my head. It proved to be no problem, however, because as I mentioned earlier additional height doesn't help much.
It may be my imagination, but I think the 220 Bucker needs a little more back pressure than the old one did to get the tail down. This is purely academic, however, because I never did get the hang of making a good three-point in this bird. The gear is very soft, and it reacts to overcontrolling on the rudder (which I seem to do the first time I land a Jungmeister ... every time) by waddling back and forth, rocking, and dipping its wings. That's a little like a puppy growling though, because there aren't any teeth behind all the commotion ... the Bucker lands easily, it just wants you to think it's hard. A Citabria is a good comparison in the landing regime-but that's the only comparison.
I wish there was a way that I could take every pilot in the world, whether interested in aerobatics or not, and let him fly an airplane like the Jungmeister ... just so everybody could see how piggy their usual flying machines are. There's no reason in the world why all airplanes can't have the control response and handling of a Jungmeister, if not the acrobatic capabilities. The Bucker was designed in 1933 using basic laws of nature and basic structures, so American industry sure as hell ought to be able to duplicate its ease of flight.
I refuse to say that I like the Jungmeister the best of any akro ship I've ever played with, but it certainly is one of the most fun. As a matter of fact, if you get on top of the highest deck of Cu clouds some day, clear up to eternity's gates, I think you may find that Saint Peter blows off steam in a Jungmeister
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