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GREAT PLANES LANCAIR ES ARF
SPECIFICATIONS RCM PROTOTYPE SUMMARY
The full scale Lancair ES, like this model, is a kit plane. For $68,900 (plus freight) you get a couple of very large crates delivered to your door. After adding an engine and radios (avionics), plus several thousand hours of assembly, painting and upholstering, pas-sing various inspections and extensive test flying, you can have a beautiful, fast and comfortable, state-of-the-art, four place, FAA licensed private airplane. Fortunately, the Great Planes 80" version (a little under 1/5 scale) is a lot less expensive and much easier to assemble. After 25 hours or so of easy assembly (no painting or upholstery is required), you will also wind up with a fast and beautiful, state-of-the-art airplane, you just won't be able to go anywhere in it. (There is always a trade-off isn't there?) Seriously though, the Great Planes Lancair ES is a surprisingly good scale model of a difficult subject. If it flies as good as it looks, it's a winner! The Lancair comes in a full color, 47" x 13" x 12" box that is nicely packed, with the usual plastic bags and corrugated dividers to protect the contents. My kit arrived with no damage. The built-up, fully sheeted and MonoKoted wings and airfoiled tail surfaces are very nicely built, with only the usual bubbles and minor wrinkles to iron down and the hardware and accessories are top quality. And the fuselage is gorgeous! That voluptuous flowing scale shape, great fiberglass work, perfectly painted (and the paint matches the MonoKote on the rudder almost perfectly) ... even the gold trim stripes are painted on. The cowl, wingtips, and wheel pants are just as good. Those big dark tinted windows are factory installed, and the cowl fits perfectly, leaving only a thin, almost flush joint. The trim lines on the cowl and fuselage match perfectly as well. Even a Scale Masters level builder would be proud to have produced this fuselage.
Great Planes instruction manuals are among the best and the Lancair manual (39 pages, excellent photos and drawings) does not disappoint. There are even a couple of pages of set-up and flying tips directed specifically at the Lancair. Assembling the Lancair is very quick and easy, but working with a fiberglass fuselage is a little different than working with wood. Almost nothing is actually glued to the fiberglass. The instructions specify which adhesives to use for each step, and it is a good idea to follow them. I used Great Planes CAs and epoxies throughout, and they performed exactly as required. An unusual feature of the Lancair is the method used to mount the aileron servos. These servos are mounted near the wingtips in the thin part of the wing, and standard size servos, mounted to the back of plywood hatches in the usual way (as the flap servos are) would not fit within the wing. The instructions have you epoxy standard servos directly to the under-side of the top wing sheeting and the kit includes plastic covers to hide the part of the servo that still protrudes. Glider pilots have been doing this for years, but in this application, I wasn't comfortable with it. Instead of the standard servos, I used a pair of Hitec HS85 MG mini servos, which offer the same torque as standard servos, but in a much smaller package. I copied the flap servo mounts on a smaller scale and everything fit nicely into the available space. Interestingly, the horizontal stabilizers are removable, even though the wing is one piece. The instructions give you the option of permanently attaching the stabs, which would make them a bit more rigid, but I built them in the removable configuration, and they haven't loosened up after numerous flights.
The O.S. .61FX and Top Flite in-cowl muffler fit completely within the cowl. The author added cowl mounting blocks to give the cowl a little more support and a remote glow plug lighter. The only holes required in the cowl are for the high and low speed needle valves and the exhaust extension. During the assembly of my Lancair, I ran into a few minor parts-fit problems. These are things that an experienced modeler will be able to overcome fairly easily, but I will mention them here so that future assemblers will know what to expect and what I did to correct them. The flap hinge slots in the right wing were cut too low. I beveled the top of the slot in the wing and the bottom of the slot in the flap so that I was able to hold the flap in the proper orientation while the CA on the hinges set up.
All servos are mounted internally using solid steel pushrods in plastic guide tubes. The receiver and battery are located behind the wing. The Lancair uses seven servos in all. The wingtips don't fit well. Cutting a 1/4" slit along the trailing edges of the tips where they overlap the wing seemed to help. Then I used CA to tack-glue them in place so that I could get them aligned properly before making them permanent. The bottom two blocks supporting the rear pushrod support former will not fit in place as shown in the instructions, but it's okay because they are not needed. The bottom screws go into the existing blind nut mounts. The photo for step 10 on page 14 shows the front pushrod support former installed backward. After following the engine mounting instructions to the letter, my engine wound up 3/16" too high and 3/16" too far right to center the spinner in the cowl. Other builders I've spoken with have not had this problem but in any case I'd suggest that you tack-glue the engine and mount to the firewall and test-fit the cowl before you drill the holes in the firewall for the blind nuts. Following those engine-mounting instructions also resulted in a 3/16" gap between the cowl and the back of the spinner (see "Engine" below). The main landing gear is not symmetrical. It can be installed backwards and the instructions don't tell you which way is correct. A call to Great Planes revealed that the correct way is with the tapered edge to the rear. Mounting it the other way will move the axles back 1/2"-3/4", increasing the required take-off speed and putting a higher stress on the nose wheel. The pushrod holes in the front and rear pushrod support formers do not line up well with the servos. You will need to use a Dremel or a round file to enlarge the holes to keep the pushrods from binding.
Engine: The recommended engines for the Lancair are .61 2-stroke or .91 4-stroke. 4-strokes are nice and you can use a 3-blade prop, but the .91 won't fit completely inside the Lancair's cowl. In an effort to keep the Lancair as scale looking as possible, Great Planes designed a neat, fully enclosed installation for the .61 using the Top Flite in-cowl muffler. If you use a remote glow plug lighter for the .61, the only visible hole needed will be the one for the needle valve. I decided to give the 2-stroke a try.
Unfortunately, this decision resulted in a couple of annoying problems that could have been avoided by using the 4-stroke. First, as I mentioned above, mounting the engine on the mount with the recommended distance from the firewall to the front of the prop driver left 3/16" or more of gap between the cowl and the back of the spinner. With the 4-stroke you would just grumble a little and move the engine closer to the firewall. You can't do that with the 2-stroke because the in-cowl muffler takes up all of the available space. I substituted a Goldberg spinner for the kit spinner. The Goldberg has a recessed backplate that takes up most of the extra clearance.
Secondly, the fully cowled 2-stroke needs a lot more help in the cooling department than the more exposed 4-stroke. Great Planes has thoughtfully taken care of this by providing a cooling air tunnel to be added to the bottom of the fuselage and a baffle to be fitted inside the cowl. Unlike the rest of the kit, the parts fit of these items was not good. The fiberglass cooling tunnel is flat, but it must be mated to the round bottom of the fuselage. I cut off the flanges on the front of the tunnel and most of the flanges on the sides and rear. Then I used a heat gun to reshape the rear of the tunnel to more-or-less match the curved bottom of the fuselage. And finally, I had to carefully cut the bottom of the fuselage so that the rear of the tunnel fit with a butt joint in the middle and an overlap at the sides. (At least that big hole makes it easy to reach the tank support former. I enlarged the opening in the former and fitted some padding around the tank to minimize the possibility of fuel frothing from vibration.) The baffle, which is specially cut for the O.S. .61FX and Top Flite in-cowl muffler, must be hand-fitted to the cowl. Be careful here. If the baffle is close to fitting, you can force it into the cowl, but that will warp the cowl, which will then no longer fit onto the fuselage. Cut and try until you think it's right, then tack-glue it in place and try the cowl on the fuselage. Everything has to fit properly before you epoxy the baffle into the cowl. I spent several hours hand-fitting these two parts ... and neither is required if you are using the 4-stroke engine. On the other hand, it is nice not having a big hole in the side of the cowl, and the O.S. .61FX with the Top Flite in-cowl muffler has proven to be a quiet, powerful and completely reliable combination. (It doesn't overheat, either.)
The author built these wood hatches and substituted Hitec HS85MG high torque mini-servos for the standard servos recommended for the ailerons. The standard servos require a bulging plastic cover, but the mini-servos fit completely within the wing. Radio: I used a Hitec Flash 5x with five HS425 and two HS85MG servos, and an 1100 mAh battery. The fifth channel on this radio is a non-proportional three-position switch. Using this, I set the flaps to be fully retracted with the switch in the up position, to drop to the recommended low rate position with the switch centered, and to the recommended high rate position with the switch down. These settings turned out to be just right (see "Flying" below). Great Planes sent along a number of their accessory and tool items to use with the Lancair. All of them were good quality and did their job well, but one was a standout. Their "Servo Horn Drill" is basically a 5/64" drill bit with a knurled handle attached. This is a very handy tool that makes drilling out servo arms a quick, simple task and the resulting hole is a perfect fit for a 2-56 size pushrod. The Servo Horn Drill now has a prominent position on my workbench.
Flying: My Lancair came out nose-heavy. I filled the stabilizer joiner tube with 1-1/2 oz. of lead shot and epoxy, but that wasn't enough. It took another 3/4 oz. of stick-on lead weights to bring the C.G. to the recommended spot. Lateral balance took 1/2 oz. in the left wingtip. I set all of the control surface travels at the recommended high and low rates.
The Lancair is a beautiful and fairly expensive airplane with long skinny wings, a short fuselage, a relatively high wing loading and standard equipment flaps. That's a combination that will make even the most experienced test pilot just a bit nervous before the first flight. Relax; the Lancair is easy to fly. Great Planes has done a fantastic job of making a difficult scale subject fly like a good sport plane. I ran the Lancair through its paces with no nasty surprises at all.
The first flight revealed that the trims were very close (the factory did a good job of building everything straight) and the recommended C.G. was just a bit nose-heavy (good for first flights). After a few flights, I settled on low rate ailerons and high rate rudder, with the elevator travel set at halfway between low and high rates. No expo-nential was used. Here are my flight test results: Take-off (no flaps): A fairly high speed is required, but take-off and climb-out are very smooth and stable. Take-off (with low-rate flaps): Shorter, slower and more scale-like. High speed: This airplane is very fast at full throttle. Like the full scale Lancair, it wrings maximum per-formance from average power. It tracks well, but will wag its tail a bit in rough air. Low speed: Even without flaps, the Lancair will slow down to landing speed with no hint of wing rock or tip stall. Like all "barndoor" ailerons, these begin to lose their effectiveness at very low speeds, but the rudder remains effective for steering. Stall (power off): When the Lancair finally does stall, the nose drops straight through about 45 degrees before flying speed is regained. There is no tendency to tip stall. Loops: Big or small, the Lancair tracks through them very well. Rolls: The Lancair is a scale model of a non-aerobatic airplane. It does not roll like an Extra. It is difficult to maintain a level course throughout the roll. She does a beautiful barrel-roll though. Knife-edge: Incredible as it may sound, the Lancair is the best knife-edge flier I have ever flown. (Yes, I'm the guy who tested the Patty Wagstaff last year.) With no corrective mixing whatsoever, the Lancair will fly most of the way across the field in knife-edge without touching the ailerons or elevator. When I get tired of flying scale, I do a few knife-edge hori-zontal figure eights with it just for fun. Spins: Easy to enter, easy to exit, no tendency to go flat. Great for scaring the spectators. Snap rolls: Tight and easily controlled, but hard to maintain heading. That scale thing again. Landing (no flaps): Smooth and fast. The Lancair does not slow down easily. Landing (with high rate flaps): Slower, scale-like with a high rate of descent, which allows you to keep the idle speed up for better engine reliability. Deploying the flaps causes the airplane to climb, and it is necessary to hold in some down elevator on take-off and landing to maintain a constant rate of climb or descent when the flaps are used. Mixing some down elevator to the flap switch would take care of that automatically.
Conclusion: The Lancair is a gorgeous airplane, with a great presence in the pits and in the air. It is not a beginner's airplane, but an experienced modeler will have no trouble assembling or flying it. Aside from the crowds it draws in the pits, I think the most fun thing about the Lancair is the flaps. Their effect on the flight characteristics of the model are exactly like the effect of the flaps on the full scale airplane and with a little practice a half-flap take-off or a full-flap landing will look so real it will bring a tear to your eye. Not to mention the cheers from the spectators. Photos by Jim Feldmann. Reprinted with permission.June, 2004 R/C Modeler Magazine Editor: Patricia Crews
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