You would be hard pressed to find anyone with a bad word for the 48" Moth by North County Flying Machines (NCFM). The Moth is perhaps the closest you can come to a "do-it-all" glider. I can not say it any better than NCFM's description: "It can be bungee launched and specked in flatland thermals, slam a turn and fire out the other side in slope competition, or dropped into the backside for high speed dynamic soaring." Flying on the solid reputation of the 48" Moth, the M60 was introduced with much anticipation and demand; in fact NCFM had a waiting list of over 100 customers in line for the first production runs of the M60. NCFM is a company of fliers who push the envelope of design and construction techniques. You can usually find Derek or Harris on the slope testing their designs and looking for any small improvements that can make their planes fly better or be more durable.
The 60" EPP M60 Kit and Building
The M60 Kit is typical of EPP planes, you open the box to find foam, some wood parts, and a few bags of accessories. What sets the M60 apart however is an abundance of Carbon Fiber rods, 4 of them to be exact. The main wing spar is made of two rods joined in the middle by a machined aluminum coupler. The secondary spar is a single thinner rod, while the fuselage requires one as a longeron. The wing cores and fuselage were very cleanly cut out of 1.9lb EPP and did not have any EPP hairs to remove. A test fit showed that the wing roots fit perfectly together with the main spar channel aligned. I took an inventory of the remaining items in the kit which consisted of a pair of matched aileron stock, two balsa sheets for the vertical fin, basswood for the drag spar, a titanium drag spar joiner, various control horns and linkages, and detailed instructions.
Building the wing consisted of joining the two halves with your favorite glue and letting them dry in the wing beds. Next you mix up an ample amount of Epoxy (15 minuet set time at the quickest), pour it into the pre-cut Main Spar channel, and joining and inserting the Carbon Fiber Main Spar and aluminum joiner. A little EPP trimming was required to fit the joiner in the spar channel. Installing the Secondary Spar is not quite as easy due the fact that you need to cut out a channel for it. If I had one recommendation for the kit it would be for NCFM to pre-cut the channel for the secondary spar. Other than that you just glue it in place and form a cap for it. The kit includes a balsa cap for the main spar that you must glue in place and then sand flush with the wing surface. It helps the fit of the cap if you round out the edge of the cap that joins to the main spar. The secondary spar and ballast tube will be capped in a similar manner.
Wing halves joined and in beds
The drag spar assembly consists of basswood strips that you epoxy to the trailing edge of the wing core. The only concern here is to make sure that the strips are aligned with the wing and that they have good adhesion. A small titanium strip is glued across the two basswood halves at the root to reinforce this joint. The drag spar is important in that it is responsible for the stiffness of the trailing edge of the wing and provides a solid point for the attachment of the elevons.
I chose to install the optional Ballast Tube per the instructions. This was an easy, yet time consuming step in that you need to buy some brass tubing, plug the ends, cut a section, rout a channel in the foam, glue the tube in place and cap it. Then after the tube is installed you need to cut another section into small pieces and fill them with molten lead.
Brass ballast tube and secondary spar
Once the previous steps are completed, it is time to install the servos in the wing. The servos are installed about 15" out from the wing root right on the trailing edge side of the main spar. The NCFM instruction manual goes into detail on how to "pot" the servos. Potting the servos is a process where you wrap a servo in plastic wrap and press it into an epoxy lined cut-out in the wing. Once the epoxy dries, the servos will just snap in and out of their location and are held very firmly in place.
Servo potting (note secondary spar cap)
The build manual for the M60 calls for very little strapping tape to be used. Essentially you just cover the leading edge of the wing with 3 pieces of 1" strapping tape; one top, one bottom, and one around the leading edge that overlaps the first two. I was skeptical about the rigidity using this sparse amount of tape, but was pleased to end up with a very stiff wing. The main concern with using more tape is the resulting weight behind the CG.
Taped wing showing servos routing of servo wires.
I strayed from the manual a bit on the wing-tips and modified the trailing edge. I did this by cutting about 1" from the Elevon stock and epoxying it to the basswood spar. I then reinforced this with strapping tape. I like the look of the fixed stock at the trailing edge, but more importantly, this modification adds a degree of protection for your servos. On a less than perfect landing, if the wing-tip hits the ground first the fixed stock will take the hit instead of the elevon. On the down side, this modification could lead to slower roll rates.
There are very few steps required to complete the fuselage. The first step is to glue the provided longeron in the pre-drilled hole. The Longeron provides the back-bone of the M60 and really stiffens up the EPP Fuselage. Shaping the fuselage after the longeron dries is a very straight forward procedure. NCFM has come up with a simple mathematical coefficient that when multiplied by the fuselage width at any given point gives a reference point for cutting the fuse. If you cut along the guide points per the instructions, then all that is required if some minimal sanding to get a nice rounded fuselage. The last step before the covering/gooping process is to cut and glue the battery/radio compartment. To do this you simply cut a slice off of the foam block that is removed from the radio cavity. You then goop the slice back into place on one side to form the compartment. I shaped a couple extra pieces of foam so that they fill the voids around the battery and provide extra durability in the front area.
Shaping the fuselage (note guide dots)
Covering and Joining the Wing and Fuselage
Covering the wing of the M60 is very simple. I would recommend a highly visible color scheme for the M60. The wing is thin and narrow and there is not too much fuselage to see, so the bright colors really help with orientation when the plane get further away. I chose to use Ultracoat but you can also use Solortex. I left about 2 inches at the root uncovered so that the goop will adhere better when joining the wing to the fuselage.
Wing ready to install
NCFM devised a unique alternate method for covering the fuselage; you thin and paint on Goop. In order to get a smooth finish, you must first spackle and sand (and repeat a few times) the EPP until all the small voids are filled. Be sure to let the spackle dry thoroughly between coats. After you are satisfied with the finish, you then spray paint the fuselage in your chosen colors / pattern. In preparation for applying the thinned Goop, you should find a secure method to support or hang the fuselage. I thinned the Goop using Xylol (Xylene), but the manual calls for using Toluene. Start by mixing 2 - 3 parts thinner to 1 part Goop; you are looking for a thin Maple syrup consistency. I found that if you mix up about ½ a tube of Goop, it will keep it's consistency if you seal it up airtight between applications. Once the Goop is thinned, just paint it on the fuselage with a cheap brush. My coats were dry and ready for another in about one hour. You can add as many coats as you wish, but remember that you are adding weight with each one (I did 3 coats). Your Goop covered fuselage should dry to a nice clear, rubbery texture.
Fuselage gooped and drying.
Once you have your fuselage Gooped, it is time to glue the wing in place. On this step just follow the directions and do your best to avoid getting Goop all over the place as you slide the wing in place. To get the servo wires to the receiver cavity, I bored a hole from through to the wing cut-out. I used a piece of string tied to the servo leads to pull the wires through the hole as I slid the wing in place.
Pulling wires into receiver cavity
Once the wing has had a chance to dry in place, then install the elevons using your favorite hinging method. You will probably need to trim a couple of inches off of each elevon in order to make them fit.
The vertical fin is an easy step in building the M60. The kit comes with two pieces of balsa that you join using CA. You then cut the fin to the shape of the included template. The manual calls for covering the vertical with Ultracoat, however I did mine different. I used wood stain followed by a polyurethane coating followed by a coat of thinned goop. This gives it a nice natural finish and is still quite durable. To install the fin, you cut a channel in the fuselage, making sure that you have it straight and plumb. Next you pot that channel similarly to how you potted the servos. The fin should fit in snugly following the potting, and should stay in place with a small piece of tape wrapped around the rear of the fuselage boom and up on each side of the fin.
Cutting the fin
The final stage in building the M60 is installing the battery and receiver. There is ample room in the nose of the fuselage to fit your choice of batteries. I turned to Cermark http://www.cermark.com/ to supply the 5 cell 720mAH battery pack for my M60. Cermark not only has great prices, they also have a great browser for finding batteries. You first select if you are looking for a pack or a single cell. Under single cell you chose Nicad or NiMH then rapid or standard charge cells. Under Battery Packs, you start by selecting the voltage (number of cells) you are looking for. After you pick you voltage, you select the capacity cell that you need, then finally you chose your configuration and connector. Choosing all your equipment should be this easy. Place the battery in front of the receiver to help get the weight further forward and so that the battery does not slam the Rx on any nose in landings. Once you get the battery in place, you can glue in the hatch . I added a few scrap pieces of EPP to hold the battery in place and strengthen the nose of the plane. It is extremely important to only use a high quality receiver in a fast slope plane like the M60. For this application I chose to use the Hitec Electron 6 http://www.hitecrcd.com/product_fs.htm . Hitec has a solid reputation for making bullet-proof receivers with good prices. With the speed of the M60 a glitch near the ground could quickly result in a destroyed plane. Hold off on gluing the receiver hatch until you have a chance to balance and test fly the M60 so that you can add or remove weight as needed.
Balance, Pre-flight check, and Test Throws
Accurately finding the Center of Gravity on the M60 is exceptionally critical. You can not just be "in the ball park", or "close" you must be right on. My first "flight" was less than stellar due to an overly aft CG condition. I quickly realized how important an accurate CG measurement is on the plank style planes. This degree of accuracy can not be obtained by balancing on your finger tips. You need to have a balance jig with relatively sharp tips to get an accurate measurement. I put two flat tip screwdrivers in a vice so that the tips are level and balanced the M60 on them. I was surprised at how far off my finger tip balancing was. Plank style gliders are very sensitive to CG, just 1/8" makes a very noticeable difference in flight.
My M60 required about 2 ½ oz of lead up front to balance correctly. I hollowed out a couple of small cavities above and below the battery to hold stick on lead weights. This got the CG to the recommended location. I would then be able to fine tune the CG after I had a few flights on the plane.
Another thing to take very seriously is the recommendation on the elevator throw. The build manual calls for 1/8" up and down for the elevator function. Any more than this really makes the M60 hard to control. For the aileron function, you can dial in as much throw as you like. I will mention that the M60 does require a Computer Radio with the ability to dial in separate throw amounts for the elevator and aileron functions. Once you get the CG and control throws dialed in, give the plane a few test throws. It should glide nice and straight for quite a ways.
Flying over the Pacific
Out of any plane that I have built and flown, the NCFM M60 has come with the highest expectations about flight performance. The 48" Moth (the little brother to the M60) has a great reputation as a fast and agile, yet versatile slope glider. The M60 was hailed as at least it's equal but fly faster and turn better. The M60 did not disappoint me at all. My first flight after getting the CG accurately located (yet not fine-tuned) was very impressive. In moderate lift conditions, the M60 whistled by the slope, pulled some tight turns and generally flew great.
Follow NCFM's instructions on Fine-tuning the CG. These are on their web-site and in the build manual. They basically instruct you to slowly move the CG rearward until you have difficulty controlling the plane, then move it forward just a bit. This takes numerous landings and adjustments, but it is worth it. The M60 just keeps getting faster and more maneuverable as the CG gets closer to optimum. Just keep in mind that an adjustment as little as 1/16" makes a noticeable difference. I did not believe it until I experienced it first hand.
Once the CG was dialed in, the M60 really came alive. The plane just does not seem to run out of energy during large vertical maneuvers; it pulls huge loops and consecutive Cuban 8's. Inverted flight is very stable and only requires slight pressure on the stick. The M60 also has great low lift abilities and is therefore able to venture far out from the slope face in search of thermals. The roll rate is the only flight aspect that left me wanting more as the rolls were not very axial and a bit slower than I expected. My wing-tip modification is the most likely cause of the slower roll rate. I plan to experiment with aileron differential to see if it helps with rolls.
I hate to report my findings on durability, but after a hard crash I have the experience to do so. I thought that I could get away with not gluing my vertical fin in place as the potting was very snug. I found out in one of my early flights that I was wrong. I was pulling a hard turn when I saw the fin fly off. The M60 took an immediate dive at the ground and bounced about 4 feet in the air after it hit. The nose of the plane now had the accordion look and there was a small wrinkle on the wing-tip, but other than that it was fine. The accordion nose straightened out with some heat and an iron helped the wing-tip. Moral of the story: glue in your vertical fin. The M60 owes its durability to the EPP construction.
As of this writing, I have not had an opportunity to ballast up my M60, but by all accounts it should just scream in good lift conditions.
The M60 by North County Flying Machines is as close as you can get to a one plane quiver. The kit quality is evident as soon as you open the box. The wing cores are cut to exacting standards and match perfectly. The build manual is detailed in words, yet sparse on pictures. I do think that a few more pictures in the manual would benefit the novice and veteran builder alike. That being said, the build is fairly straight forward and easy. Customer support with NCFM is second to none. Derek is always quick to respond to e-mail questions and usually answers the phone (and is more than happy to help) when you call. The flight characteristics of the M60 are phenomenal. The plane works in very light lift, but really comes alive in winds over 10mph. The M60 turns sharp and precise and seems to exit the turns just as fast as it goes in. I would not recommend the M60 for a first slope plane, as it is fast and quick. It is a sloper that you must stay on top of, but you are rewarded with a high performance, versatile, durable glider.
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