Budd Davisson, EAA/Sport Aviation, November, 1994

Homebuilt Pogo Stick

Oshkosh is a lousy place to evaluate an airplane. Especially when said airplane hops off the ground like it has JATO and wants badly to climb out of sight long before it reaches the end of the runway.

Considering the several dozen airplanes in the pattern, I reluctantly dropped the nose and started out over the lake keeping several eyes peeled for traffic. Gheez, this thing wanted to keep climbing!

My introduction to the Murphy Rebel 160 may have been less than optimum in terms of the environment in which I had to operate, but I still learned the most important fact about the airplane: It was designed and built to scratch the itch for a utilitarian airplane. Period! It made no pretense of offering unbelievable speed or being able to leap entire continents in a single bound. It made no pretense of being sophisticated and sexy. Actually, it is so straight forward in every aspect of both its aeronautical and structural personalities it makes no pretenses at anything.

What it does do is present the homebuilder with an airplane he can use the way most of us actually use airplanes. Even though it has the fuel and speed for crosscountry work, it is ready made for local flights and for poking around in those out of the way airports, lakes (hopefully, after installing the floats) and meadows that beg to be visited but don't look very user-friendly to your average Spam can.

A 160 hp Lycoming hides under the vaguely rectinear cowl of the newest Rebel and that gives the boxy little bird a go-get-'em personality on takeoff and climb that adds one more adjective to its utilitarian discription..STOL. Drop the hammer and watch the runway drop away. Simple as that.

To many of us in the south country ( the company, is located near Vancouver, B.C. Canada) the Murphy Rebel is something of an unknown. We don't see many of them and that's a little surprising considering the company is about to deliver its 1000th kit, over half of which are Rebels.

One reason they are not as well known down here as in Canada is that they reflect something of the parent country's personality. When the term "bush plane" is uttered, listeners almost never picture New Jersey or Oklahoma. Nope, its always Canada or Alaska that leaps into mind and for good reason. Up there they have good uses for STOL/bushbirds and that's the Rebel's personality. Especially with the 160 Lyc dragging it around.

Another reason the airplanes aren't seen often is that we are only now coming to the end of the traditional three year gestation period that begins when the first kits of a new design are delivered. Last year there were no Rebels at Oshkosh. This year there were seven. Murphy expects as many as 100 may fly this year, so Oshkosh could easily see the Rebel crowd bursting at the seams next year.

Structurally, the airplane is interesting for a couple of reasons. In the first place, it is a professionally designed and engineered unit. Second, it is all aluinum and third, Murphy has incorporated state of the art CNC techology to make the kits super easy to assemble.

Darryl Murphy teamed up with ex-deHavilland head of engineering Dick Hiskocks when he decided to build his idea of a bush bird. Hiskocks was part of the original design team on the Beaver and a lot of that design philosophy shows in the Rebel. For one thing the fat 4415 wing utilizes three spars and a bunch of stringers for stiffness. On top of that the fuel is kept in wet sections of the wing and is easily expandable from the basic 25 gallons to a whopping, bladder busting 50 gallons for those serious about staying up there a while.

The fuselage is a rounded box most notable for its width, 44 inches across the shoulders, which puts it in C-182 category and 7 inches wider than a C-152. It is the width of the cockpit combined with the small size of the airplane that gives it a deceivingly boxy look. It is visually wide for its length. The anti-canning creases seen on the sides of the fuselage replace the stiffners of the original design and save nearly four pounds while eliminateing a bunch of parts and rivets.

And speaking of rivets, that is one of many areas where Murphy has worked hard to reduce building time. The airplane is specifically designed around the Avdell Avex blind rivet. Although appearing to be of the common pop rivet (actually a brand name) design, the Avdels are universally accepted in Europe and are considered aircraft quality. Although the mandrel is not mechanically locked in place like a Cherry or Huck MLS, their aluminum shell is designed to retain the mandrel as long as practical. Because the aircraft design takes into account their lower strength (167 pounds in shear versus 357 pounds for an AN 4 in similar skin) there are lots of rivets to be pulled, nearly 20,000.

The real beauty of the pulled rivet in this application is that it works with the Murphy's pre-punched components to eliminate the need for traditional jigging. Other than a 16 foot table that has to be perfectly flat to act as a datum, nothing needs to be constructed other than the airplane itself. Lots of aluminum designs demand a sizable time investment in jig construction to ensure a straight airplane. The Rebel, however, depends on the flat table and the accuracy of factory-punched pilot holes to jig the assemblies.

As the kit is delivered, the skins have all holes punched via CNC machines. There is no bending of any components to be done and matching tooling holes are located in individual pieces to aid in positioning the skins. The builder draws centerlines on internal components such as ribs, the centerlines are positioned in the pre-punched holes of the skins, and matching holes drilled to size.

When this type of tooling is combined with the blind rivet, it is easy to see why so many Rebels are under construction and why so many are about to be finished. The skill levels usually associated with jig construction and traditional riveting are no longer necessary. The learning curve for this type of construction would be almost non-existent.

A builder could, if desired, use bucked AN rivets in place of the Avdels, although the airplane would have many more rivets than necessary in that case. Also, there exists the probability that AN 3 rivets, rather than -4s, could be used in place of the 1/8" Avdels because of the strengh is there and the weight would be less. This is subject to final engineering verification and would undoubtably increase building time substantially because the Avdels are so quick to install.

Originally, the Rebel had a "V" type bungee gear but on the later kits they ahve gone to an aluminum Wittman type gear. This combined with the sleeker cowl for the 160 engine upped the speed of the airplane to a solid 125 mph in cruise. More important, according to factory test pilot Rob Dyck (Jack, this is correct spelling), it greatly improved the airplane's ease of landing and it rides rough fields much more smoothly.

The airplane is shipped in three basic kits, the empennage ($xxx), the wing ($xxx) and the fuselage ($xxx). If bought all at one time,. the cost (fall 1994) would be $xxx.

The airplane is appoved for four engines and the gross wieght is changed changed to match the engine. The 66 hp Rotax 582 is stickered at 1057 pounds (Canadian ultralight), the Rotax 912 at 1450 lbs, the 0-235 Lycoming at 1650 pounds and the 0-320 at XXXX pounds. According to those at the factory who have been keeping track of customer's airplanes, a 912 airplane should empty at about 600 and the 115 hp Lycoming birds in the 825-875 pound range. The 160 hp version they had at Oshkosh emptied at 950.

We poked around in a builder's manual and, although its hard to say how good a manual is until you actually try to use it, it looked to be not only complete but detailed in a very commonsense sort of way. For instance, in the tools required to build each component they listed a felt marker. One entire step was spent waiting for the epoxy chromate primer (supplied) to dry because, if left tacky, it would later catch and trap drill filings. Nice touch!

Incidentally, the way the parts are prepared and the way the manual reads instills confidence. This is not always the case. Reading some manuals leaves you overwhelmed. My feeling after reading this one was, "...even I could build this airplane..."

Whether their estimates of 500-600 hours to build the basic airframe is correct or not is hard to verify, but given the methods used in construction, the time estimates may just be right.

I knew absolutely none of the above, when I scrambled into the cockpit at the end of Runway 36 at Oshkosh. All I knew as I scrambled into the right seat was this was one of the very few homebuilt aircraft I had boarded that had seats adjusted via Cessna type rails rather than the stack-a-cushion system.

The door latch, like so many parts of the airplane was simple and to the point: a spring loaded dog stuck out the back edge and was retracted by pulling on the cable running through the middle of the door. Very positive. Very simple. Very light.

Settling back in the seat and trying to orient myself I noticed I felt I was a long way back in the cockpit. Rob Dyck explained from the left seat that was the result of the 160 hp installation. They moved the firewall back three inches and the pilots almost twice that amount. The result is the front door pillars appear further forward than normal and the overhead cuts off some upward vision. Even Rob said they needed to open up the skylights further. The headliner is a premolded piece that looked to have plenty of room to install bigger skylights which would do wonders in opening up the feeling of the cockpit and increasing upward visibility. Personally, I'd open up the entire panel behind the main carry-through back to the stringer over the pilot's head. If it needed more structure to do that, it would be a worthwhile investment.

What the cockpit lacked in light, it more than made up for in room. It was much, much wider than it looked from the outside. Further, as I glanced around inside, I noticed the third seat in back and asked Rob about it. They designed the airplane to handle 200 pounds in the back seat and the real fuselage has a floor so it can be used as a camper. Rob said he stretched out back there and slept all the way back from a fly-in while the other two kept their eyes open.

It wasn't until the airplane was running that I noticed I had no brakes on my side. Normally, not a big deal, but as soon as I started the turn onto the taxiway I could tell the tailwheel springs were too soft to get any immediate resonse out of the tailwheel. At a couple of points i had to ask for some brake just to make it around the corner.

Running the MAC electric trim indicator into the green, I kept an eye on the flagperson standing at the edge of the runway and immediately powered up onto the centerline at her request.

On the runway, It was clear the airplane had good visibility over the nose. I couldn't see straight ahead without stretching just a little, but the edges were clearly visible, although the door pillar was slightly in the way.

Cleared to go, the throttle was gently pushed forward, but from the way the airplane reacted, you'd have thought I hammered the throttle. For what looked to be a normal high wing airplane, this thing rapidly assumed the personality of a boxy bullet. As the throttle found the panel I eased the tail up and gently played with the rudders. They were effective, but the airplane didn't really need much from me to stay straight. More or less straight anyway.

The tail was barely off the ground when the airplane launched and I ran into the aformentioned climb problem. There was no doubt in my mind I could easily have had 3,000 feet at the other end of the runway, the way that thing was going up hill. Rob said it was about 1,200 fpm, but at 70-75 mph that gave a deck angle that approached ridiculous. Without thinking, I throttled back, as I pushed the nose over, because my gut told me anything with that kind of takeoff and climb performance was going to put its nose down and start really hauling and I didn't want that much speed in the pattern.

My gut was wrong. With a 15% airfoil, it wasn't about to accelerate through Mach. It hit a drag wall and hung in there at about 125 mph while I stuck my face in the windshield looking around the wing root for all the traffic I knew was out there.

Once over the lake, I let the nose up and we went upstairs in a hurry.

We leveled out and I started playing. As I did Rob reached up to the overhead lever and put the flaps into a 6 degree reflexed position which he says tacks a few knots onto cruise.

I rammed some aileron into it without rudder to see how much adverse yaw it had and was surpised to find it had very little. I had expected those Hershy bar wings to require lots of correcting rudder but they didn't. The rudder was plenty effective, but very little was needed for coordination.

The ailerons themselves are Cessna-normal. Nothing out of the ordinary with Spam can roll rates. In otherwords, it doesn't have a quicker than normal feel that many homebuilts exhibit. Later, during stalls with the ailerons drooped, the roll response fell off because of the drooping, which is one of the reasons they limit it to 18 degrees. Other than the change with flaperons out, the controls on all axis will feel very familiar to anyone flying the airplane because they are right in the middle of the profile. They feel a little like every airplane but exactly like none

With enough altitude under us, I brought the power back and crept up (or is it down?) on a stall. Somewhere around 45 mph it started buffetting and the rate of descent went up a few hundred fpm and the stick was against the stop. The flaperons made very little difference in the nose attitude or speed bleed-off but they did knock at least four mph off the stall. When totally stalled and clean the ailerons and rudder worked nicely and easily controlled the airplane. With the flaperons out, the control was noticably softer. Given time I would have liked to mess with very slow speed turns or turning stalls and see if large aileron inputs in those situations would stall the inside wing. Rob says they've looked at that but haven't found it to be a problem. Still, it would be fun to investigate it.

I poked and prodded the airplane and found the only thing I actually didn't like about it was the visibility and the general "dark" feeling of the cockpit. A lot of older airplanes (Pacer, Maul, Chief, etc) are that way, but the Rebel doesn't need to be. Larger skylights would make a big difference. Past that, there isn't much that could be changed.

We threaded our way through traffic back to Oshkosh and I did my best to get the airplane slowed down to the 65 mph Rob wanted on final. Unfortunately, we were forced into flying a bastardized wide, fast approach and I never really had a chance to get it trimmed up on speed.

That however was no excuse for the lousy landing I made.

I'm here to tell you the spring gear on the airplane really works well. Even though I touched down harder than necessary with a little drift to the left, the airplane didn't hop, jump or try to bite either its own tail or mine. After touchdown I did, however, find I would have given anything for a set of brakes or much tighter tailwheel springs. Between the two of us, Rob and I put on quite a show. If I had done a better job on short final all the gyrations wouldn't have been necessary, since even though I gave it every opportunity, it never did anything particularly spooky. Just embarrassing.

The ground handling, had I done my part and had the tailwheel been a little more responsive, was actually not much more difficult than a Citabria. I think!. The forgoing, the pilot and the tailwheel springs, made it appear more difficult than it was.

During the entire approach at no time did the nose get in the way. It wasn't until just before touchdown (such as it was) I was even aware the nose was out there.

The Murphy Rebel and its apparent success says something really important about sport aviation and the markets it represents. At the very least it says there is a market out there for a really usable airplane that has a little character all its own. It says there are a lot of people who want airplanes that are practical in the ways they personally define that word. They don't need 200 mph or aerobatics or any of the other flash and glitz that is so much a part of some designs. They aren't looking for Shelby Cobras, they are looking for four-door Chevies they can drive and drive and drive. That's the Murphy Rebel. Its an airplane for the masses. Its an airplane to be used, not simply owned.

Maybe that's why its named the Rebel. It is going against the current trend, marching to its own four-cylinder dummer and all that.

The Rebel is a usable airplane and that's saying a lot. BD