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| Replica Aircraft Topics related to the construction of WWI replica aircraft |
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2 July 2006, 08:56 PM
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#11 (permalink) | |
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Scout Pilot
Join Date: Oct 2004
Location: Hazelton BC Canada
Posts: 440
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Quote:
 What rpm will your ranger be turning? It will probably require about 450 - 500 ft. Lb. torque to spin my prop. Will your ranger make that kind of torque? Troy. |
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2 July 2006, 09:01 PM
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#12 (permalink) | |
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Scout Pilot
Join Date: Oct 2004
Location: Hazelton BC Canada
Posts: 440
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Quote:
 Once I started to use the home made draw knife it went a lot better! Also if you suffer a momentary spell of insanity and decide to do yours this way, a variable speed angle grinder and a 40 grit pad does the trick getting them smooth enough to sand and pollish!Troy. |
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2 July 2006, 09:23 PM
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#13 (permalink) | |
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Scout Pilot
Join Date: Oct 2004
Location: Hazelton BC Canada
Posts: 440
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Quote:
When I said lash, I meant rotational play at the prop tip! Back and forth play is scarey!!  As for a good PIREP on auto conversions, there are a few out there. The guys flying the SAL mustangs are using a V8 and planiary re-drive (not cheap, but my engine and drive are pushing 10K) Also Belted air is having a lot of good success with no problems to report. That said you are right, there are many "Cheapy" PSRU / Auto conversions out there! I'm not sure if a Ranger would fit or not, do you have any idea how long one is? My Ford is about 4 feet front to back and there is around 2' of width available. Thanks for the kind words and encouragement! Regards; Troy W. |
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3 July 2006, 06:28 AM
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#14 (permalink) |
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Forum Ace
Join Date: Oct 2004
Location: Cheltenham
Posts: 1,566
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Great looking airplane!
Regarding the Ranger L440; The engine has the following dimensions: Length:53.2" Height:31.25" Width:21.4" Total weight, dry is 396 lbs. There is quite a bit of work invovled in 'inverting' the inverted engine, but well documented and straight forward. The added plus is that it's aircooled. To the best of my knowledge, the max prop that a Ranger will pull is one of Chad Willie's 94" props made specifically for Rangers in WW1 reproductions. All the best with your project, Regards, Maxim08 |
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3 July 2006, 09:24 AM
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#15 (permalink) | |
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Scout Pilot
Join Date: Oct 2004
Location: Hazelton BC Canada
Posts: 440
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Quote:
To spin my Axial prop will require something in the neighborhood of 450+ lb/ft Torque. I don't anticipate any problems other than the odd leak and tuning issues with my set up. It has been done successfully before and though sound is nice, so is performance. The original BMW / Mercedes powered DVII really performed! About 2000 fpm climb at lower altitudes and that at around 65mph at a 40 deg angle. It was swinging an enormous prop at slow speeds which I've read was key to the 40deg. . There is an interesting article on the DVII performance at http://calbears.findarticles.com/p/a...342008climbout It really is a great read and shows the potental of this aircraft with the right prop spinning the right speed. I thought it would be worth the hassel of an auto conversion to get that performance. My engine combo. will have between 525 ft. lb. Torque (worst case) and up to a maximum of 680ft. lb. torque at the prop hub. I'm not expecting as much as the highest but somewhere in the middle around 600 or so. That would equal a 160 hp original engine, and I'll still be turning the engine slow (2600 cruise) so it isn't a souped up engine at all. My Hot Rod / racing twenties showed me that as soon as you over do an engine its reliability goes out the window! Sorry to be so windy Troy W. Regards; Troy W. |
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3 July 2006, 09:28 AM
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#16 (permalink) |
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Scout Pilot
Join Date: Oct 2004
Location: Hazelton BC Canada
Posts: 440
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Link didn't work
Well the above link didn't work so here is the artica. Hope it isn't too lnog for the forum?
Troy W. Flying the D.VII: A fabulous Fokker fighter Flight Journal, Oct 2003 by Meyer, Corky ANTHONY FORKER'S FABULOUS WW I FIGHTER-THE D.VII-WAS THE LOCKHEED F-22 OF the 1930s era in which I grew up. It was the model airplane of choice for my generation. Its clean, elegant lines and great flight characteristics appealed to us much more than the bulldog look of the French Spad. The Fokker's mystique was enhanced in our minds by the fictional battles published in pulp magazines such as G-8 and His Battle Aces: there, the round-goggled Phillip Strange heroically fought off the square-goggled Barons von something-or-others' Fokker D.VIIs at 10 to one odds. I had another reason to be enamored by the Fokker D.VII: in the ancient Mechanics Machinery building at the Illinois State Fairgrounds in my hometown of Springfield, Illinois, hung a stodgy Curtiss Jenny JN-4D trainer and a real live Fokker D.VII! It hung so near the balcony railing that I could almost touch its lower wingtip. Its magnificent BMW 185hp engine rested in a glass case on an adjacent balcony. Every year, I spent hours staring at the D.VII, wildly imagining that I was flying many daring and successful air battles against it. Epilogue for that Fokker D.VII: about 20 years after WW II ended, I asked my brother, who still lived in Springfield, whether the Fokker still hung there. He told me that the fair's officials had deemed it a useless, archaic exhibit and had taken it down, stored it outside until it had rotted and rusted and then trashed it just a few years earlier. I also felt trashed. Sic semper tyrannis! [Thus always to tyrants.] A REAL FOKKER D.VII ENTERS MY LIFE In 1962, I heard that a neighbor about a mile from my home on Long Island, New York, was building a Fokker D.VII replica from scratch. Needless to say, I was at his door in a heartbeat and met Fred Berg, a quiet but direct gentleman who was a tenured professor of manual training arts at a local college. He showed me the half-completed aircraft in his four-car garage. It was immediately obvious that he was a first-class craftsman. His work was impeccable. He told me that he chose to construct a Fokker D.VII because his father had been a mechanic in a Fokker D.VII squadron during WW I. Reason enough. During the following seven years, as construction progressed, I occasionally made my way to his home. Several times, I diplomatically suggested that if he needed a professional test pilot to fly it, I would be pleased to do so. He replied in a polite but forthright manner that he planned to teach himself to fly in that very airplane-a not so subtle hint that I would only be a spectator to his Fokker flights. As the time for first flight neared and Fred talked to people at the FAA, he found that they were similarly forthright and told him that he could not fly his Fokker over the heads of taxpayers without an FAA-approved pilot's license. My worth suddenly became more apparent! Fred asked me to fly his magnificent machine. My offer to test-fly it at Grumman's 10,000-foot Calverton runway instead of in a cow pasture may also have appealed to his sense of safety and desire for his aircraft's longevity. Fred had done a great research job before he started to build the Fokker. From the USAF Wright Field Archives, he had obtained much specific material on the static and flight tests performed there in 1920 on several of the 142 Fokker D.VIIs that had been shipped to the United States as war reparations. The static-test report on the wings stated that at 5.2G, a very loud snapping noise was heard. It was further reported that the load was increased to 8G without any further noises, and nothing broke. They never determined just what caused the noise at 5.2G. Fred also visited the Aeronautical Museum in Munich, Germany, where he took many measurements from the only remaining original Fokker D.VII. He even constructed two exact replicas of a Spandau machine gun. Most of his instruments were originals from that time but had English markings. Fred apologized to me because he hadn't adhered exactly to Fokker's specifications; his modernized Fokker had wheel brakes and a steerable tailwheel instead of a tailskid. Tailskids were required for flights off grass as they provided braking and directional stability on the ground. Most private aircraft did not have wheel brakes until the late 1930s. I know this because the 37hp Taylorcraft I learned to fly in 1937 had a tailskid and no brakes! Fred well knew that a tailskid would cause disastrous skidding on a hard, smooth runway. He used 4130 steel tube instead of mild steel and modem Resorcinol adhesive instead of the horse-hoof glue used in the 1918 Fokker's construction. He also installed a small windshield, but the German Air Force hadn't required one. As far as I was concerned, Fred's well-thought-out specifications would greatly improve my comfort-and my luck! When the plane had been completed, Fred towed it on a trailer behind his truck over 20 miles of back roads to the Grumman Calverton airport, assembled it single-handedly in a few hours and persuaded the FAA to certify it as airworthy. During the inspection, the FAA listed more than 40 "restrictions that must be removed before flight," such as, the fuel cap must have a label stating that the tank could be filled only with 25-octane or higher gas. Amazingly, not one question was asked about major items such as weight and balance calculations, structural limitations, flight-envelope determination and engine integrity! The 6-cylinder, 160hp Hall-Scott engine was an "Americanized" version of the Mercedes engine used in the wartime Fokkers. Fred had found it somewhere. He completely rebuilt it to have a thoroughly accurate, reliable Fokker. He even reworked the cam system so that the propeller rotated in the correct direction. He installed an impulse ignition system that required only a 6-inch hand flip of the propeller tip to start the engine (similar to 1918 German ignition designs). It didn't require the macho "hand-propping" demanded by all other aircraft of that vintage. The engine ran like a charm during the nine flights that I made in it. The only problem was ensuring a high enough coolant temperature during my cold January flights. It was a most docile engine. With only one magneto, the only run-up test required was to see that the engine attained 1,150 static rpm before takeoff (the wheel brakes came in very handy here) and to check that the coolant was warm enough to fly. It would have been a dream for wartime interception scramble starts. I entered the cockpit on January 25, 1969, at 11:52 a.m. after a walk-around check. The engine started, and only one major unexpected problem reared its ugly head to spoil my exciting, sunny flight and my wondrous reputation as a pilot. My first takeoff was into a 10mph wind. I was caught way off-guard by the Fokker's very light, Piper Cub-like, 9.4 pounds-per-square-foot wing loading. The jet fighters I had been flying had wing loading of more than 100 pounds per square foot. I had just lifted the tail to obtain forward visibility and was ready to lower it to leave the ground, when I found that I was already about 15 feet in the air after a ground roll of only 115 feet! Torque effect had been so minimal and so easily controlled with the very large rudder's 40-degree-deflection limit that I failed to anticipate such a spectacularly fast takeoff. (I may also have been day-dreaming just a bit.) I had selected a climb speed of 80mph, and the airplane went up like an express elevator. Visibility was excellent except over the long nose, and handling characteristics were as gentle as a Piper Cub's. I soon noted that although the Fokker had adequate aileron for flight, it did not have the crisp rolling qualities that were paramount in the fighters with which I was acquainted. The rudder and elevator had a smooth, positive feel. I then remembered that Fokker pilots got directly behind their adversaries and sprayed their targets with lead by using the Fokker's very sensitive and positive rudder motions. German D.VII pilots never developed the curved-approach, lead-pursuit gunnery runs that were popular among WW II pilots. This required much greater rolling power. |
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3 July 2006, 09:29 AM
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#17 (permalink) |
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Scout Pilot
Join Date: Oct 2004
Location: Hazelton BC Canada
Posts: 440
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Part two
Continued from page 1.
I flew many stalls to explore the Fokker's behavior with various incorrect aileron, rudder and elevator inputs. I wanted to see how the airplane would perform in the hands of a clumsy student pilot, and I was pleased and amazed to find that it hadn't any wing-dropping tendencies at all. Stall occurred at a low 38mph indicated airspeed. Just before it stalled, there was adequate warning buffeting, and the nose slowly dropped to the horizon for a quick and easy recovery. Accelerated stalls showed that the wing design was perfect. I could see the great benefits of its gentle, low stall-speed and handling characteristics from the highly cambered airfoil on the tips of the upper and lower wings. Few WW I fighter aircraft knew such gentle stalling characteristics. I could easily see how novice pilots could mistreat the forgiving Fokker D.VII and yet keep their landing rolls well within the confines of the small fields from which they operated. I immediately felt at home in the Fokker. I could have readily changed my name to Korwin Heinrich Meier and shot down Allied fighters, too!  Reed Chambers, who was Eddie Rickenbacker's executive officer in the 94th Aero Squadron, was my friend for 25 years before his death. He related in great detail the not-too-gentle stalls he experienced in the Nieuport 28 and the miserable stall characteristics of the Spad VIIs and XIIIs (because their wings had very sharp leading edges). He further stated that because of these bad habits near the stall speeds, pilots approached landings much faster than they should have, and that led to more landing-overrun accidents than were necessary.Using an approach speed of 55mph, flare-out and touch-down were a piece of cake. I congratulated myself long before the rollout had finished. Complacency on landing is a well-known no-no among tail-dragger pilots, and it caught up with me-big time! The Fokker started to lean to the left, and that started a beautiful ground loop without even a cross-wind for me to blame it on. After swerving sharply to the left, I caught it by almost standing it on its nose; my honor was now tinged with the aroma of Limburger cheese. Because it had been so much fun to fly, I thought I should redeem myself for my landing ineptitude. I decided to take off again immediately before my audience caught on. The next circuit was great, until I settled onto the runway in the 3-point position. The Fokker "headed for the barn" again-but in the opposite direction. After another swerve, I caught it again with the rudder and brakes, but I was greatly perplexed at my inability to tame such a docile airplane's only bad manner. Because its wingtip had dropped slightly, both times, just before the ground loop started, it eventually struck me that the shock cords might need to be adjusted. We tightened them, and I took off for my third flight to calibrate the airspeed and to gradually increase the pullout G limit to 3.5. I didn't intend to probe that 5.2G snapping noise in the air. Very warily, I pulled G in increments up to 3.5G and decided, enough of this nonsense! I thankfully didn't hear any unusual noises. During the dives, I noticed that the Fokker's fixed-pitch propeller over-sped to 1,500rpm at 125mph indicated airspeed. Thus, I couldn't dive it any faster without seriously damaging the engine. I completed the timed airspeed calibration from 60mph to 105mph along the two-mile Calverton runway without a hitch. I also made several stabilized climbs from 1,000 to 3,000 feet to determine the speed for best rate of climb. These climbs demonstrated to me that I was way out of touch with reality when guessing the best rate of climb speed in anything but highly wing-loaded jets. The best climb speed proved to be 65mph. THE VERY UNEXPECTED PROBLEM The landing was again uneventful until I almost stopped when "Herr Ground Loop" started again. I was able to stop it more easily now that I was used to it, but it seemed to be way out of character for this otherwise mannerly fighter. When I debriefed Fred about the tenacious ground-looping tendencies, he suggested that we talk to a pilot friend of his who learned to fly in WW I and might be able to shed some light on our problem. This wise old pilot immediately asked how we had tested the shock-cord tension before each flight. When we told him that we didn't think it necessary, he gave us quite a lesson from his WW I days. He said that a 180-pound pilot must sit on the wingtip of any shock-cord-equipped airplane before every flight. If the tip goes down by more than two inches, the shock cords are too loose. Eureka! I sat on the Fokker's wingtip, and it went down eight inches! When we tightened the shock cords to our pilot friend's specifications, the plane's ground-looping tendency disappeared as though by magic. So much for my ignorance in knowledge of shock cords! On the next flight, I did loops, slow rolls, Immelmanns and snap rolls. I easily performed all except slow rolls; the ailerons needed more roll capability for that maneuver. I, of course, did not consider my lack of ability as any part of the slow-roll problem! I climbed to 10,000 feet to see what the fuss was about the Fokker's great ability to maneuver while standing on its tail with full control at 45mph indicated airspeed. I could pull it up to a 45-degree angle with the horizon and slow down to 45mph with less than full power, and the airplane was as steady as a rock. In simulated firing runs, I easily maneuvered it with both the ailerons and/or the rudder. It was unbelievable! I now understand why the British Handley Paige bomber pilots and other WW I Allied pilots were so afraid of this fighter. For the next flight, we measured takeoff and landing distances in calm conditions by having people line up on the sides of the runway to determine the exact points of liftoff and touchdown. A zero-wind takeoff was noted to be four aircraft lengths (91 feet). The landing run, with the use of brakes to simulate tailskid drag, was four-and-a-half lengths (103 feet)! It really had a great combination of slow approach speed and very short ground rolls. As I had made my flights in depth-of-winter temperatures, Fred decided to store the Fokker until spring. With its drafty cockpit and very small windshield, even my winter flight gear was not what I would rationally have selected to avoid freezing to death. When spring arrived, I made an aerial photo flight from the grass field where Fred had at last been granted an FAA private pilot's license. I know that he found the Fokker even more flawless than the ubiquitous Piper Cub he had trained in, even though his Fokker's propeller came off its shaft one day while he was flying it; he was able to land successfully without damaging his pride and joy-or his ego. CONCLUSIONS The Fokker D.VII was a fabulous fighter, but it was too late to affect the outcome of the war. Its demonstrated superiority, however, prompted the Allied Armistice Commission to demand that all Fokker D.VIIs be turned over to them immediately after the cessation of hostilities; no other weapon of war had that distinction. German squadrons burned many of the planes. Unbeknown to the Allied Commission, Tony Fokker surreptitiously shipped six trainloads of them to the Netherlands. Nonetheless, in 1919, the United States Army Air Service was issued 142 Fokker D.VIIs in 1919 as partial reparation after the war. The Navy was given six Fokker D.VIIs of the batch taken from Germany, and the U.S. Army Air Corps was given the rest. The Navy transferred them to the Marines in 1921 for use at Brown Field at Quantico, Virginia, where records show that they were flown only for about 18 months during 1921 to 1923. There is no record of their flight times. There is a note on the decommission report of serial number A-5844: "Sec. Nav. letter 3239-75 July 19, 1921, to S&A directs sale of this deteriorated airplane to the State Fair Museum, Springfield, Illinois, for $1.00." This was the one that I had enjoyed so much! THE SAD FATE OF FRED BERG'S FOKKER I'm sorry to relate that Fred Berg's meticulously constructed Fokker still languishes in his basement, even though I have tried to get him to place it in one of the many museums that would be proud to present his work of art to the public. I hope that Fred will change his mind some day. His masterpiece deserves to be recognized and appreciated by the public as a unique and historically significant |
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3 July 2006, 09:35 AM
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#18 (permalink) | |
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Forum Ace
Contributor
Join Date: Dec 2004
Location: Mississauga, Ontario
Posts: 544
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Quote:
The L440 is the 200hp Ranger. Same as what we're running in our DVII... with pretty disapointing results (At least with the current prop). The performance is nowhere near that reported from the original. Which, as you point out, is a real shame considering how well this airframe can perform with the right power-plant. Cheers Edward
__________________
Edward P. Soye |
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3 July 2006, 09:49 AM
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#19 (permalink) | |
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Scout Pilot
Join Date: Oct 2004
Location: Hazelton BC Canada
Posts: 440
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Quote:
Troy. |
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3 July 2006, 09:57 AM
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#20 (permalink) |
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Forum Ace
Contributor
Join Date: Dec 2004
Location: Mississauga, Ontario
Posts: 544
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Troy,
I'm afraid this year I'm a Triplane pilot, and have yet to fly the DVII. However in talking to those that do it doesn't get much more than about 1900 rpm... ever. The Ranger is supposed to be rated at 200hp when turning at something like 2350. Currently we're only turning something like an 86" prop, and its a big coarse thing. We had a similar prop on our Ranger powered SE5 until last fall when we put a standard Cornel prop on it (similar length, finer pitch) and it brought the RPM on the SE up from the 2050rpm range to 2350-2400rpm. The performance of the aircraft also increased in terms of cruise speed and climb. In the coming weeks we're going to find out if the same prop makes a similar improvement in our DVII's RPM, and performance in flight. We shall see how things work... Cheers Edward
__________________
Edward P. Soye |
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