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Loehle 5151 Mustang

The P-51 for Walter Mitty*

www.ContactMagazine.com

 

Loehle

Mike and Sandy Loehle (pronounced LOW-lee)
Loehle Aircraft Corporation
380 Shippmans Creek Road
Wartrace, TN 37183 USA
931-857-3419
www.Loehle.com

Loehle

* Wal·ter Mit·ty (wôl’tər mĭt’ē) n. An ordinary, often ineffectual person who indulges in fantastic daydreams of personal triumphs. After the main character in the fictional book The Secret Life of Walter Mitty by James Thurber.

It is a kind of longing within the brave man’s heart to be the hero, coming to the rescue of his fellow man (and ladies). During WW II, one of the finest pieces of equipment to allow the man to be that hero was the P-51 Mustang fighter aircraft. It didn’t take long for the enemy to realize the tide of the war had changed once the P-51 pilots were escorting the bombers to penetrate deeper and deeper into territory held by the German forces.

Fast forward 60-plus years; even the silhouette of the P-51 is still easily recognized by many school students as the hero airplane of that war. The rumble of the P-51 flying over is an unmistakable deep-throated sound that still stops people in their tracks as they watch it roar past, but to own one is but a dream for most pilots. With original P-51s going for about $2 million-plus and with operating costs well over $750/hour, it’s just not in most people’s family budget to own one. Most people just have to wait for the airshows to get a glimpse.
 
Mike and Sandy Loehle of Loehle Aircraft Corporation have a solution to help remedy this situation. They designed and produce a 3/4 scale experimental, amateur-built kit version of the P-51 called the 5151 Mustang that also fits in the new light-sport aircraft category.

Some History
Mike and Sandy have a long history in aviation—33 years and counting. Mike’s dad, Carl Loehle (who we lost in May of 2009), had switched hobbies from racing open-wheel midgets and sprint cars to flying aircraft, so Mike gained some tail-dragger time in his dad’s Luscombe and soloed in a Cessna 150 on his 16th birthday. He was old enough to fly a plane but still too young to drive a car, according to dad.

Mike became interested in learning to fly hang gliders while still a student pilot and had an early Seagull III. While he was in the Civil Air Patrol, he attended the Air Force Academy survival school in Colorado. He purposely missed his bus home from the academy so he could stop by the Leading Edge Air Foils (LEAF) store in Colorado Springs where he talked with LEAF owner Bill Raisner about hang gliding and bought some books on the subject. Mike earned his private ticket the day after his 17th birthday.

Mike’s ultralight phase started when his uncle, Dennis Benson, took him to Oshkosh in 1976. While there, he witnessed John Moody do the famous outside loops in his Icarus II and was front and center during the talks John gave to the crowds afterwards. If you look back in the Sport Aviation magazine photos covering that event, you can see a curly headed young man leaning forward, as if to catch every word John Moody said. And that was truly the case.

Mike promptly bought one of Larry Mauro’s Easy Risers and performed the same outside loops on his own (not intentionally, of course). He was involved in ultralight flying since before “ultralight” was a defined aviation term. Mike flew N-numbered aircraft that had to be foot launched, holding the throttle in his mouth and hanging on by his armpits. At that time, he used his feet position for weight and balance and almost fell out of the plane as his arms gave way from holding his weight. There were no seats back then, not even a harness (which seemed like such a brilliant idea once presented). Mike also flew the popular Quicksilver and Pterodactyl ultralights during that period.

Carl Loehle finally convinced Mike that the Easy Riser needed a tail for stability. Mike designed a tail and eventually landing gear for the Easy Riser. He machined his own ground-adjustable prop (way ahead of its time). Upon seeing success with these additions, other Easy Riser customers asked Mike to build such parts for them. He designed engine mounts for several different engines as the trend moved from the 10-hp McCullough 101 to the 35-hp Cuyuna 430. The early version of his aircraft was called the Aeroplane (2-axis control), and the company name was UFM of Kentucky. As 3-axis became popular throughout the industry, Mike designed a T-tail and did away with the drag rudders. He added a steerable nose gear and other refinements, dubbing the new design the Aeroplane XP. It was a very maneuverable, strong ultralight biplane that sold well in the early 1980s.

Mike operated his ultralight business during his high school years from his parent’s basement first, and then from a T-hangar at Bowman Field in Louisville, Kentucky, while working for Kentucky Flying Service (a large full-service Cessna dealership with 20-plus Cessna 150s available for rent, 10-plus Aztecs, and many other aircraft). He worked first as a line boy, refueling and cleaning aircraft. As KFS owner Dick Mulloy observed his dependable, responsible work ethics, Mike was soon doing actual mechanic work (with supervisory sign-offs), repainting Aztec leading edges and working on anything they would allow him to do. He was trusted to open and close the business, all of this while attending high school.

His goal of being a charter pilot led him to take advantage of as many flights as he could catch with anybody flying anywhere. His goals started to shift somewhat when he saw the admired charter pilots scrambling for work when the economy slowed.

He quickly outgrew the T-hangar and moved his business to E. P. “Tom” Sawyer State Park on the northeast side of Louisville. He was the only person that we know of who had permission to actually have an operational ultralight flight park and manufacturing facility/office within any state park system. Not only did he have an active ultralight grass runway, he also collected tie-down rent money from pilots for the state park. He introduced many people who visited the park to aviation in general and ultralight flight specifically.

Oshkosh Grand Champion
In 1981, Mike won an Oshkosh Grand Champion trophy for his shiny black Aeroplane with red/orange/yellow swirled trim. He also took the trophy for Outstanding Craftsmanship that year. It was probably the first fabric-covered ultralight with shiny paint, which started a whole new trend as people like Homer Kolb and other manufacturers took interest in Mike’s beautiful gloss finish. He also won 1981 Most Innovative Modifications and 1982 Grand Champion at Sun ’n Fun.

Mike was responsible for ultralight pilots being able to fly at two major airports in the early days when general aviation looked down on these new-fangled things. He even took his fight to be able to fly into Bowman Field in Louisville for the 60th anniversary event as far as Washington, D.C. The word came back to Bowman Field that he would be allowed to fly his ultralight at this federally funded airport, or both Bowman and Standiford Field in Louisville could possibly be closed! Needless to say, the airport authority members were much nicer to him afterwards. He was very instrumental in gaining similar rights at the Seymour, Indiana, airport for those who wished to fly ultralights there.

Enter Sandy
Meanwhile, in another part of Kentucky, Sandy Burgess got into aviation in 1982 through a friend who simply offered her a ride in a Cessna 172. She got the flying bug immediately and started taking flying lessons at the airport in Danville/Junction City, Kentucky. It didn’t take long to figure out that spending her rent money on flying lessons wasn’t a good idea, so she started looking for another way to get in the air. About this time, a friend handed her the first issue of Ultralight Aircraft magazine with a Pterodactyl on the front cover. She had never heard of people building their own aircraft and first thought this must surely be illegal. Several info packs and videos later found her drooling over an early 2-axis V-tail Klaus Hill design called the Hummer that was being produced by Maxair Sports in Pennsylvania.

Sandy laughs as she looks back. “I had to convince the banker that I really could afford the $3,500 loan to buy this airplane kit,” she said. “He just laughed at me, as did a lot of other people. Even my dad was more than a little skeptical, although I think he was secretly proud that I would do something so adventurous. So I went back to see the loan officer at the Bank of Danville five times before he finally just agreed to give me the loan. I wore him out with enthusiasm, I guess.”

Funny coincidence—in later years Sandy went back to visit the airport where she learned to fly and discovered that this banker was now part-owner of the airport. You never know what kind of seeds you’re planting!

Loehle
A Hummer ultralight similar to what Sandy built in her apartment.

Sandy continues, “I was so excited about this project! But it really hit me what I had done when I got the call from the semi-truck driver making sure he could get his truck down the street where my duplex apartment was located. I guess I initially thought it would come by UPS, but the fuselage tube was 18 feet long. The truck driver couldn’t believe he was hauling an airplane and got a real kick out of the idea that a 25-year-old single girl was going to build an airplane in her apartment.”

Sandy gathered the necessary hand tools and a Black & Decker Workmate to help hold parts in place. There was short tubing and bags of hardware and brackets where the washer/dryer should have been, longer tubing running down the hallway, and the extra bedroom was full of all kinds of parts like the fuel tank, seat, sailcloth fabric, etc. The engine was even a centerpiece on the kitchen table for awhile.

“I had a lot to learn. I didn’t know what a lock washer, a rivet, or AN hardware was, or how to drill holes in tubing—I had to learn it all,” Sandy said. “I was smart enough to ask lots of questions and get good help with the building. I certainly learned a lot in a short order.

“I insisted I wanted it to be an N-numbered aircraft so I could log my hours toward my private ticket, although the FAA inspector asked why the heck I had him come to look at an ultralight. He finally agreed to inspect the plane, and I gained my repairman’s certificate as well.”

The Hummer was ready to fly on July 4th. “I figured that was a mighty good day to fly my new airplane, but I had butterflies so bad I couldn’t do it. I must have inspected that airplane 12 times that day. A friend who helped me with the build did the test flight and came back all grins. After a sleepless night, I was on the runway the next day by 6:30 a.m. with the little 25-hp Zenoah running, waiting for the fog to lift. What a joyous occasion to finally lift off and experience flying at 30 mph! It was magnificent!”

Sandy quickly moved on to become a dealer for the Hummer and then later added the American Aerolights dealership, in turn adding the Eagle, Eagle XL, and Falcon aircraft to her offerings.

Her first encounter with a P-51 Mustang came about when the small Danville/Junction City Airport fixed base operator started planning an airshow. She wanted to help and worked tirelessly planning the T-shirts, designing and printing tickets, helping plan crowd control, etc. Someone mentioned, why not call Bob Hoover?

“I asked, who is Bob Hoover?” Sandy says. “I didn’t know. They just told me he was a pilot who often flew at airshows. When I asked how would one get in touch with him, they said he worked at Rockwell International. Being a very resourceful marketing secretary (in my day job), it was easy to get the phone number, so I just called and asked for Bob Hoover. When he answered, I explained about our small-town airshow. Come to find out, he likes small towns, and he liked my southern drawl and agreed to come!”

“Not only did he bring his world-famous yellow P-51, but I got to fly copilot in his legendary Shrike Commander on a parts run to Louisville a couple of days before the show,” explains Sandy.

Boy Meets Girl
Realizing she needed a much broader population to run a profitable ultralight dealership, Sandy moved her business to the southeast side of Louisville. At this point in time, Sandy and Mike were actually competitors. She had a beautiful 235-acre farm and a 50-acre sod farm from which to fly and train students to fly ultralights, plus keys to an approximately 75-acre private recreation area. It was great except it was so far out of the city that she had to work hard to convince people to come visit her flight location.

Mike was so focused on making parts in his facility at the busy state park that he didn’t have time to deal with all the people. After a while, it made more sense to join forces so Sandy could handle their customers while Mike handled design and production. The decision was a good one, and the business partnership eventually became a marriage partnership as well.

In July of 1984, Sandy made a call to buy more propellers from Ritz Propeller Company, only to find out that Gerry Ritz had died. Ritz propellers were known for providing more thrust than any other prop available, so they made a trip to Tullahoma, Tennessee, to pick up as many 54 x 27 LH 1-1/2” propellers as possible. Gerry Ritz’s widow, Frances Alexander Ritz, remembered Mike’s “pretty” airplanes at the airshows. She encouraged Mike and Sandy to give some thought to moving to Tennessee to utilize the 20,000-square-foot factory and 1,800-foot grass strip. Mike and Sandy were thrilled to be able to purchase the 137-acre property and moved in by November 1984. (Note: Mike and Sandy delivered Ritz propellers by the thousands to the ultralight and light plane markets before discontinuing propeller production in the 1990s).

The 5151 Begins
In 1985 they began to do some serious thinking about what airplane would sell better than the biplane and flex wing ultralights they offered, something that would sell itself and help pay for the facility quickly. Paul Poberezny was making comments that he thought ultralights would grow up to be “proper little airplanes.” Along this line of thought, Mike began envisioning a wooden ultralight P-51. Not sure how the aviation community would react, he brought just an uncovered prototype to Oshkosh to test the market.

“We literally watched people’s mouths drop open as they rounded the corner headed toward our display,” recalls Sandy. “We knew we had a winner with the idea, but everyone wanted the ‘bigger’ engine, which at that time was the Rotax 503, 50 hp.” A world-renowned aircraft designer, Leo Pazmany, took time to sit down with Mike and discussed with him areas to strengthen. Leo encouraged Mike to forget the ultralight part of the idea and build it without having to count washers, so he could try to meet the 254-pound weight limit. It was actually with a sigh of relief that Mike and his dad Carl decided to follow Leo’s advice and just build it strong and safe as an experimental category aircraft instead of an ultralight.

Loehle
EAA Hall of Fame inductee Ladislao (Leo) Pazmany was a prolific designer of homebuilt aircraft and a well-respected aeronautical engineer. His designs have survived his passing and remain current and relevant. They can be viewed at his website: www.Pazmany.com.

Carl Loehle was a math whiz (one of the few to score a perfect 100 on his military entrance exam) and drew the whole plane in great detail on 25 large blueprints. When asked about safety factors, he often explains that he knew his own son would be the test pilot, so he built the cockpit area structure to protect the pilot, while outlying wing sections, the scoop underneath, and other sections would incrementally absorb impact. Within 11 months, the Loehle 5151 Mustang went from idea to flying!

Loehle

While keeping the lines of the P-51, they deviated a lot in construction methods compared to the original fighter. Most notable is the fact that the 5151 is made from wood instead of aluminum, and rather than being covered in aluminum it’s covered in fabric.

“We chose wood in order to fulfill several goals,” says Mike. “Wood is easy to work with and is comfortable to the amateur builder. Most have worked in wood in some fashion, whether building a house or shop, cabinets, tables, or other familiar items. So the idea of epoxying wood parts together is not intimidating.”

Construction
Mike showed he’s quite confident about the strength of the design when he said, “The wood construction allows the aircraft to be lightweight yet strong, which means it can operate with just a 65-hp engine. This helps keep overall costs low, much lower than if we went with metal or composite construction. We also chose to do our calculations on clear, northern white pine instead of spruce, as it was becoming scarce and expensive. So we decided to sidestep that problem by opting for clear, straight grain wood from near the Canadian border. The pine is a little bit heavier but still plenty strong, so we designed based on its structural properties from the beginning.”

“We took the idea a step further,” continues Sandy, “and precut and numbered all the parts for this aircraft kit.

Loehle

Many kit manufacturers supply raw materials and blueprints, but Loehle created a higher standard by prefabricating the parts so each builder can be assured that by simply following assembly instructions, they will have a great-looking replica of the P-51. This means that ordering a 5151 Mustang is much like ordering a top-of-the-line balsa model kit except that the parts are bigger (which means they’re easier to work with than tiny model parts), and when you’re finished you actually get in the airplane to enjoy the flight phase.”

Mike explains that another reason for going with wood is to keep the aircraft in the speed range to reach another goal—to make it behave like a Piper J-3 Cub. It seems like an oxymoron to want a fighter to behave like a trainer aircraft known for having docile flying characteristics, but this allows the low-time Walter Mitty fighter pilot to easily handle the aircraft without getting into trouble. In fact, time in a J-3 Cub is the best way to train for flying the 5151 Mustang.

The parts numbering system is very simple. The fuselage numbering starts at the nose as Station 0 and moves toward the tail in relative inches to Station 235. Parts with no prefix in the part number are fuselage parts. Wing parts are prefixed with a “W,” canopy parts with a “C,” elevator parts with an “E,” and so forth. Hardware is supplied in plastic baggies organized by where it’s used.

“People are just amazed when they realize how much work we’ve done in this kit, even the FAA manufacturing inspector who came to our factory in 1986. He quickly pointed out that the individual steps to epoxy the parts together, fabric covering, install instruments, and other tasks would allow this kit to be in the experimental category of the amateur builder, doing in excess of 51%. It fits in the new light-sport aircraft category as well.”

Loehle
The above plan-view illustration shows that, with the empennage not installed but with one wing in place, the 5151 can be fit into a two-car garage in two different orientations.

The aircraft can be built in a typical 20’ x 24’ two-car garage. The construction order is basically the same as the way the partial kits are numbered: fuselage, vertical fin and rudder, formers, outer wing spar, center section spar, wings, canopy area, landing gear, tail wheel, control (or guide) system, horizontal stabilizer and elevator. The fuel tank, rudder pedals, instruments, engine wiring, and other systems are installed along the way before closing up the left side panel. With the fuselage built and center section in place, the builder then constructs one wing at a time. Once the left side is complete, it can be removed to hang in storage. The fuselage can then be moved to allow room to build the right side wing panel. This allows the construction to continue in the two-car garage up to the point of moving to the airport where both wings can go on.

It’s time to build
With most of the parts cut at the factory, only basic hand tools are required to assemble the 5151. A drill press, table saw and sander are handy, but even those aren’t required. Typical tools to have include pliers, small tack hammer, hand saw, electric hand drill, wood rasp, sandpaper, sanding block, C-clamps, spring clamps, plastic clothespins (to use as clamps in lightweight areas), wrenches, pocket knife or razor blade knife, level, square, string, lightweight staple gun and staples, staple remover, center punch, and a cable swaging tool. A tried and proven two-part marine type epoxy called T-88 is the primary fastener. This epoxy is mixed in equal parts, dark and light tinted fluids, within a small waxless paper cup. The builder has about 20 minutes to get the parts aligned and clamped. The Loehle-recommended cure takes 24 hours. At this point, the epoxy joint is like a metal weld—the wood surrounding the joint will break before the epoxy. Any temporary fasteners such as staples can be removed once the epoxy cures.

Loehle utilized Gerry Ritz’s structure-in-the-slot method to make it easy to align parts. The uprights, longerons, and other primary members have a single or double groove cut in them to allow the standard gussets to slide in to form a perfect 90-degree angle cluster. This allows a dry run of sections of the aircraft so the builder can envision what is supposed to happen before the finality of applying epoxy. Also utilized in certain areas is a lightweight geodetic construction method that reduces weight yet maintains rigidity from the bridgelike crisscross technique.

Loehle
5151 Mustang fuselage built by Michael Smith of Monterey, California

Fuselage
The fuselage is a very simple structure that’s based on a design called the DeHavilland box, which is a plywood-covered structure that carries the fuselage flight loads. The curved stringers on the top and bottom of the fuselage are simply cosmetic additions to give the 5151 its shape. The fuselage top and bottom are assembled flat on a workbench. Parts to do this are supplied already precut, grooved, and even tapered for a perfect fit. The gussets used in the box fuselage are die-cut for consistency. The side fuselage uprights are installed after the top and bottom are finished. The front section is then ply covered on all four sides. The rear is braced with lightweight 3/4-inch-wide geodetic strips. This whole structure can be built easily in a week.

The formers are precut, curved, plywood pieces that give the top and bottom of the fuselage the beautiful flowing look of the P-51 Mustang. Precut formers save the builder a great deal of valuable time and ensure that the true P-51 look will be maintained. These formers are epoxied to the plywood that covers the front of the fuselage or to cross members in the rear section. The 1/4” x 3/4” stringers are then located and epoxied to the formers using the supplied die-cut stringer attach (SA) parts. The bottom front formers cleverly hide the engine muffler, which is completely out of sight, helping maintain the P-51 look.

Loehle
Anyone who has ever built balsawood aircraft models would have to fall in love with the beauty of this structure.

Wings
The center section box spar is the heart of the 5151 and is built flat on a workbench. The spars are prelaminated out of 1/8-inch veneer and are cut to size. Waterproof glue is used in the lamination process. The 12-inch-wide box spar uses four prelaminated spar caps. The two upper caps are a full 3 inches thick, with the bottom caps measuring 1-1/2 inches. The box spar is ply covered on all four sides and is attached to the fuselage using 1/4-inch aluminum plates. The landing gear is mounted at each end of the box spar. The outboard wing panels can be removed from the spar ends via aluminum fittings, leaving an 8-foot-wide structure that also houses the optional wing fuel tanks.

The outboard box spar is also built on the bench and is 12 inches wide as well. The inboard portion is ply covered and transitions to 3/4-inch-wide geodetic strips in the tip area. The outboard wing panels can be removed easily.

The 5151 wing is tapered in all directions. The ribs are naturally smaller (in both chord and camber) as they move toward the wing tips. All wing ribs are made from plywood and are precut to shape so no rib jigs are needed. All the actual airfoil shapes are established at the factory since the ribs are profile shaped. The wing has a 2-degree washout built into it for docile stall characteristics. The rib sections are simply glued to the front and rear of the large box spar, and the rear portion of the rib is glued to the rear plywood webbed aileron spar with 3/4-inch caps. Wing tip ribs are epoxied to a specially machined trailing edge; ribs are capped in place using 1/8” x 3/4” caps. The leading edge of the wings is covered in plywood. The aileron is built right into place and is cut out after the wing ribs are capped. Five aluminum premachined hinges are used to attach the aileron (like the elevators). The ailerons are cable actuated using 3/32-inch aircraft cable for a proven trouble-free system.

The wings are easily removed in about 25 minutes by unfastening the five bolts through the aluminum wing attach brackets that hold the wing panels on each side. These are accessible by unfastening the thin gap cover to reveal a roughly 5-inch-wide space to get a hand in to loosen and remove the hardware. A quick disconnect allows the ailerons to be detached. This wing removal feature allows an individual to easily transport the aircraft to/from the airport or to airshows when weather or time wouldn’t allow participation otherwise.

Loehle
Mike is teaching 5151 customer Terry Tengler how to cover his rudder.

Empennage
The vertical fin is built in place on the aircraft using premachined spars and laminated curved ribs. The spar webs are even precut to allow a perfect, uniform, and straight spar assembly. Tail ribs are assembled over full-size rib patterns using laminated rib caps and either precut ply ribs or geodetic construction, and the actual rib spacing is set for the builder by the factory notching the rear spar caps. The leading edge of the vertical fin is plywood covered using very lightweight ply epoxied around die-cut nose rib formers. Geodetic strips are then installed, providing the fin with torsional stiffness. This whole method of assembly is fast and fun to build and provides a strong, lightweight cantilever surface.

The rudder and the horizontal stabilizer are constructed similarly to the vertical fin. The 4130 steel rudder horn is precut and bent to shape. Rudder hinges are also cut to length and attach the rudder to the vertical fin. The rudder is cable actuated using 3/32-inch aircraft cable connected to the wooden rudder pedals hinged to the floor.

Ribs of the horizontal stabilizer are assembled using prelaminated rib caps and either precut ply rib webs or are built up using lightweight geodetic. Stabilizers are built on the aircraft utilizing a unique method of attachment consisting of wood sockets that slip onto aircraft-grade aluminum tubes. This unique feature allows the tail surfaces to be removed for transporting and storage of the aircraft. The surfaces are secured onto the aluminum tubes using aircraft bolts, and removal takes only 1-1/2 minutes per side. The horizontal stabilizers also use geodetic bracing to provide torsional strength. Leading edges are made of plywood wrapped around die-cut rib nose formers.

Elevator ribs are built over full-size plans much like the rudder. Spars have plywood webs. The elevator also utilizes a specially machined-cut trailing edge. The elevator is hinged to the horizontal stabilizer using premachined aluminum hinges mounted with aircraft machine screws and tee nuts which are permanently mounted into the wood spars. Hinges also have the hinge pins permanently installed by the hinge manufacturer. Many well-known aircraft utilize this simple hinge method such as Cessna, Ercoupe, and Pietenpol. The elevator is controlled using aluminum push-pull tubes for a positive, direct control movement.

Canopy
The bubble canopy is custom formed just for the 5151 Mustang so that each one is identical. This allows the preformed metal frame to be riveted to the canopy while sitting on the workbench. The canopy slides on a track with small rollers and mates with the preformed aluminum tube windshield frame. When properly installed, the canopy actually pushes forward in flight, but most builders add a simple locking mechanism. The three-piece windshield is joined and riveted with preformed aluminum joiners and give the aircraft a very realistic P-51 Mustang look.

Loehle
This partially complete project is showcasing many of the prefabricated fiberglass pieces offered by Loehle, designed to speed up the build process and to smooth out the compound curves. It’s also sporting the Walter Mikron inverted inline four.

The Business End
The huge spinner assembly is approximately 18 inches in diameter and consists of the composite spinner as well as two fiberglass bulkheads (one at the rear between the propeller hub and the prop flange and one inside the spinner sandwiched between the propeller and the squash-plate). Bulkheads are formed to perfectly fit the cone at the appropriate station.

The P-51 just wouldn’t look right without the air intake scoop underneath the cockpit area. While the 5151 version serves no function other than good looks, it’s still necessary for the correct profile. This is accomplished with a built-up wood former/stringer base and the fiberglass scoop capping the front of the area.

The kit provides a translucent rotationally molded plastic 5-gallon fuselage tank that is installed in front of the rudder pedals. Fuel level is determined by observing fluid level against marks on the side of the tank. Most builders choose to add the optional wing tanks, which add 4 gallons in each wing for a total of 13 gallons. The fuel selector valve lets the pilot choose whether to feed from the main tank or both wing tanks at the same time. A floating cork wire serves as fuel level indicator in the wing tanks, easily observable from the cockpit.

Loehle
There is ample room between the engine compartment and the cockpit so the Rotax muffler is hidden away nicely. The opening in the bottom of the fuselage is large enough for servicing but still hides the muffler well.

The standard powerplant for the 5151 Mustang is the Rotax 582, 65-hp liquid cooled two-stroke engine which has been used successfully in light-sport aircraft for approximately 20 years. This engine allows a takeoff roll of a mere 150 feet and a lively climb rate of 1,200 feet per mile. Loehle prefers the Rotax because they are tried and proven in many thousands of aircraft around the world, engines and parts are easily obtainable, and because of the availability of dedicated service centers for tech help and quick repairs. The slim dimensions of the 582 solve the dilemma of keeping the engine within the confines of the narrow nose without engine parts hanging outside the cowling ruining the sleek fighter looks.

As for alternatives, there are a few—not exactly something Loehle has encouraged, but there are options. One of them is the 60-hp Walter Mikron that they helped the builder install in the beautiful red/white/blue 5151 on the cover of CONTACT! Magazine issue #94. They had high hopes that this 90-plus-year-old proven engine would work well. It looked good, sounded good, even had the exciting cloud of smoke when it started up the first time. Based on looks alone, it seemed more massive and “proper” and had a deeper, throaty sound that a two-stroke would never give. Unfortunately, the builder kept adding more and more weight to the airplane until it wasn’t really a fair test. The result was poor performance compared to the 582, and he is afraid to even get in and out of the factory grass strip, so it stays at paved airports. Just not enough oomph to do the job compared to the agile performance the other Loehle pilots in the area enjoy. He’s considering the next larger size Walter engine.

Loehle
This might be the biggest departure from the P-51 profile; the chin-scoop has been enlarged to accommodate the Rotax radiator. Some might argue that it belongs in the belly-scoop, but weight and simplicity dictate this location.

Another engine they were hopeful about was the Harley Davidson marketed by the now defunct Hog-Air. It just seemed like it could be a match, about the right size and horsepower, and the unique sound was appealing to a P-51 crowd as well as to those who just love the Harley sound.

Loehle
The “Hog-Air” Loehle 5151.

They worked with Hog-Air to install one in a customer’s airplane and were able to show it at Sun ’n Fun before the customer took delivery. Loehle never received the feedback from actual flight time experience they had hoped for, so the jury is out as to whether it’s a good match or not.

Loehle had one customer install a Suzuki who seems to be happy with it. A handful of other builders have either installed or plan to install the three- and four-cylinder Geo/Suzuki engine, most with the Raven redrive. Mike has never been particularly interested in using a “worn out” car engine for his airplane, so he hasn’t participated much in this. Loehle has at least one customer who could have been flying 6 or 7 years ago easily if he had just put the Rotax 582 in and gone flying. He’s on his fifth redrive unit and has cooling problems. He has even written articles encouraging builders to “stick to the plans if you want to go fly.” Basically Loehle feels that if someone decides to go with an alternate engine, he or she has taken on a second project in itself and will definitely be the test pilot at this point.
 
The VW or any other boxer engine is definitely out; although it might be able to power the aircraft, the lines would be totally ruined, as it won’t fit in the narrow nose area. Who would want a P-51 with cowl cheeks?

Loehle
The “stock” Rotax 582 is dwarfed by the spinner.

Since Mike and Sandy have tried to supply everything possible with this kit, they just prefer to keep providing something proven that they can order several at a time, keep in stock, can get repair parts easily, and allow the builder/owner to use any of the multiple service centers around the country that can assist him or her, as needed.

Loehle
An example of the 5151 cockpit. As with any experimental, the instrument panel will vary from one to another.

Retractable Gear
The 5151 started out as a fixed-gear-only fighter with the idea that it was best to keep it simple. Public opinion won the debate over whether it should have fixed or retractable gear when the factory designed a simple worm gear arrangement of retraction that is operated with a hand crank mechanism. The load is relieved by a large spring inside the wing panel so that operation is easily accomplished while tending to flying matters. Cranking the handle for approximately 11 seconds brings the 4130 chromoly gear legs up or down. Position is signified by a fail-safe mechanical indicator near the wing leading edge that is attached directly to the retract hardware.

Loehle

Bottom Line
How long does it take to build this P-51 replica? “We’ve had one customer complete his 5151 project in 452 hours from crate to runway, but most take anywhere from 750 to 1,000 hours, depending on which options are chosen. As with any project, those making modifications and who deviate from the plans can expect longer build times,” says Sandy.

This whole idea has been quite successful, with over 450 kits now being built and flown in 26 countries around the world. One of the high points of becoming a worldwide exporter of the 5151 came when it passed the strict German regulations without any modifications at all. Once an aircraft passes these scrutinizing requirements, most of the other countries throughout the world recognize this standard as more than sufficient for their acceptance.

When asked about the cost of the 5151, Sandy explains, “Some prefer to order just the complete airframe kit (less engine) which includes all the basic wood and metal parts (cut and numbered), hardware, as well as the spinner, canopy, and fixed gear. This kit is currently $13,995 (or $16,188 for the retract version). There are a lot of options available such as wing tanks, composite nose, several smoothing fiberglass fairings, spoke wheels, instruments, fiberglass wing/tail tips, ballistic parachute, fabric through paint, stars/bars decals, etc. Others want everything all at once—so we add all the options in at about $36,000.” That’s perhaps the easiest method for the factory and the builder. On the other end of the spectrum, for those with a desire to build but with a limited budget, Loehle offers partial kits in either Kit A through C or Kit 1 through 11. So a person can get started for a little over $6,565 for Kit A or $2,640 for Kit 1 if they wanted to go that route.

Other Warbirds and Ultralights
The Loehles now have eight nostalgic aircraft kits, including the 5151 Mustang, P-40 Flying Tiger, and KW-909 with WW-II “clothes.” Each of these wooden aircraft utilizes similar construction techniques on a basic frame, with cosmetic changes to make it look like their respective original counterpart. This allows many of the same parts to be utilized for the main structure, providing many benefits for the factory and an excellent safety record of tried and proven techniques. Each is fitted with the same Rotax 582 engine package with 3.48:1 gear ratio, except for 2- , 3- , or 4-blade propellers as deemed appropriate for the look. Prices are similar to the 5151.

Loehle
Partially complete Spitfire Elite on display at Sun ’n Fun '08.

The Spitfire Elite is also built similarly but is a faster aircraft with a totally different and thinner elliptical wing. It’s provided as an elite package with all the options (except engine) automatically included, and it’s priced at $34,995 (less engine). This aircraft has probably captured the look even better than the earlier replicas, while sporting options for the Rotax 582 or the 4-cylinder Rotax 912 80-hp engine.

Loehle

The classic wooden Sport Parasol was added as an entry-level project (350 hours build time, cruises 60 to 65 mph), and is probably one of the least expensive aircraft kits anywhere at only $7,995 (less engine). Even with the Rotax 503 and all the options, this simple-to-build fun flyer is only about $21,000.

Loehle
The Loehle Spad XIII (above), Fokker D.VII, and SE5a are cleverly designed around a common, highly engineered airframe; cosmetic changes in the cowlings, wing tips, and other details characterize each model.

The WW-I biplanes (Spad XIII, SE5a, Fokker D.VII) are made of aluminum tube fastened with rivets, much like Mike’s earlier Aeroplane XP construction methods. Much of the work is done in factory fixtures so the customer receives the fuselage, wings, and tail already built and then partially disassembled to ship. The builder focuses mostly on installing instruments, engine/prop, hooking up the controls, and handling the covering and painting. The rigging, which is critical on a biplane, can even be done at the factory.

Paint Products
Loehle has also developed a complete aircraft paint line for metal, composite, and fabric-covered aircraft called Loehle Aero Coatings. Since all their aircraft are fabric covered but also have composite and metal cosmetics, Mike Loehle created a paint system that moves easily from one surface to another while maintaining the same color regardless of which medium is underneath.

Loehle
5151 Mustang wing in wet-looking Loehle Aero Coatings finish.

“What we’re best known for is the extreme high-gloss ‘wet look’ finish that is possible with our system,” says Mike Loehle. “With the whole system being of the same chemical family, we can easily move from primer to color to clear without long waiting periods for one stage to chemically cure before moving on to the next step. In fact, we use the same thinner throughout the whole process. We’ve developed a high-build primer for working out blemishes easily, along with our Loehle Wonder-Fil that provides a wipe-on/wipe-off solution to pinhole problems. This eliminates the need for hours and hours being spent trying to get rid of annoying pinholes on composite parts. The filler/UV blocking primer goes on thick to allow quick filling of the weave in composite parts, with customers reporting that they’re saving up to 2/3 of the time normally required to address these problems. Each step has Loehle Ultra-Flex built in, as well as UV protection.

“This paint system was quietly developed in-house for our own use on demonstrator aircraft over the last 20 years along with the kits, but we just introduced the paint to the public a few years ago. We are now providing paint for all kinds of aircraft, not just our own.”

Realizing the increasing media coverage of light-sport aircraft and that many aircraft manufacturers would focus on two-place trainers, Loehle chose not to deviate from their forte of single-place fighter replicas to follow that trend. “It didn’t seem smart to try to be one of the 100[-plus] companies offering a two-place light-sport trainer with all the competition vying for the same market,” explains Mike. “We chose to expand our horizons instead and introduced a line of paint coatings to service a much broader market (virtually all of aviation) from ultralights to jet fighters—literally. We have been instrumental in restoring an F-15 and a Grumman Avenger to display status for future generations to enjoy. We now even have coatings on the launch pad at Cape Canaveral.”

“It’s not uncommon to provide paint for a high-tech aircraft like Lancair, Glasair, or any of the RV series and in the same day, ship paint for a SeaRey, MiniMax, or Quicksilver ultralight/light-sport aircraft,” adds Sandy.

Loehle
Loehle Aero Coatings applied to an RV-10.

The Loehles recently added yet another facet to their ever-growing aviation enterprise; they now utilize the huge WW-II hangar at the Tullahoma Airport to paint aircraft for individuals who choose not to do their own painting. Some of the projects completed are a top-of-the-line 300-mph Lancair IV Propjet, an RV-10, restoring an aerobatic Decathlon to its original paint scheme, Bellanca Viking, Luscombe 8A, BD-5, and canopy repairs/paint on a Silent 2 Targa sailplane. Mike is now repainting a Cessna 210, with a Lancair Legacy next on the schedule.

Loehle

Other upcoming projects include an F-15 for a museum plus focusing on Van’s RVs and Lancairs. This large facility allows virtually any size aircraft to be handled. Loehle Aero Painting has certainly been well received, and word of Mike’s perfectionist work has spread quickly.

Loehle
Loehle factory, aerial view (obviously)

Mike and Sandy have two teenaged sons, John (19) and Matthew (17), who have some flight time in general aviation aircraft and sailplanes. Both help with miscellaneous jobs when not busy with school activities.

Mike joined the ranks of highly recognized aviation pioneers and significant contributors by being inducted into the EAA Ultralight Hall of Fame in 2008 at EAA headquarters in Oshkosh, Wisconsin. Sandy describes the ceremony as a “magical night of honor” and expresses almost disbelief that it could possibly be true that this is their 33rd year in the aviation industry. Mike says he felt quite humbled that night standing beside other Hall of Fame inductees such as John Dyke, and recalled how he as a young aviator pored over magazines featuring the Delta Dyke design. Mike’s contributions have been numerous, but probably the currently most well known is the replica of the beloved P-51 for the pilot with average skills and a family budget.

Mike was also the recipient of the Light Aircraft Manufacturers Award (LAMA) in 2003. Being voted as a valuable contributor to the light aircraft manufacturing arena is something he deems an honor.

So whether someone is interested in a nostalgic P-51 warbird to call his own or interested in paint for his current aircraft while pondering that idea, the folks at Loehle Aircraft can help. They can be reached by phone at 931-857-3419 or by mail at Loehle Aircraft Corp., 380 Shippmans Creek Road, Wartrace, TN 37183. Better yet, check out their website www.Loehle.com for more details and sign up for the newsletter.

Performance
Cruise speed 75-85 mph
Stall speed 30 mph (no flaps required)
Vne 100 mph
Takeoff roll 150 feet
Landing roll 250 feet
Climb rate 1,200+ fpm w/Rotax 582*

*varies with gear box ratios and propellers

Specifications
Wing span 27 feet, 5 inches
Wing area 130 square feet
Length 22 feet, 10 inches
Width 8 feet (wings removed)
Empty weight 575 pounds
Gross weight 900 pounds
Useful load 325 pounds; 247 pounds full fuel
Load factor +4, -2g’s; +6, -3 ultimate
Fuel capacity 5 to 13 gallons
Options
Retract landing gear
Custom wing tanks
Electric start vs. pull start
Ballistic parachute
3-blade or 4-blade propeller
Deluxe interior package
 
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