|Apr 26, 2011, 03:17 PM|
NitroPlanes Extra 330L EP Build
After taking a hiatus from RCG for about 6 months after dealing with some riff-raff on the site plaguing various threads, I decided to return to RCG for a number of reasons. At any rate, it's time for a new blog entry...
So my next project will be to build a sizable electric powered Aerobatic plane late this Spring before the flying season gets underway out here in soaked WNY. The flying fields are under water in many areas so flying season is still a few weeks out. I decided to invest in a NitroPlanes Extra 330L EP, it has a 53" wingspan and an approximate AUW of 5-5.5 lbs. Considering I own a slew of 3S 2200 and 2650mAh battery packs, I wanted something more appropriate for 6-cell pack use, so I can pair up my 3S packs in series, which is what I use in my 500-sized Trex clone heli.
Here is a photo of the model courtesy of NitroPlanes.com:
The NitroPlanes product link can be found below:
I plan on beginning the build this upcoming weekend. So this plane is sort of borderline regarding 6-cell battery use, but I like over-powering planes and this one will not be an exception. Size-wise, the Extra 330L EP is comparable to the the E-flite Carbon-Z Yak 54, but a little larger and heavier (the 330L is composed of balsa/ply rather than z-foam).
Here are the power components I have chosen thus far:
ESC: Castle Creations Phoenix 80-Amp (internal BEC disabled)
UBEC: Turnigy 3-5A Switching UBEC
Motor: Turnigy 50-65A 400kV
Servos: Hitec HS5485HB Digital Karbonite Servos across the board - inexpensive standard digital servo, light-weight, plenty of torque for a 5-5.5 lb. air frame.
Prop: 14x8.5 thin electric APC
Estimated power draw will be in the 800-900W range with the above power/prop setup. I settled on the Extra 330L EP because the model was designed for electric power, and it's balsa/ply construction will allow for more precision aerobatics. I'm not someone who likes to spend a ton of time building and don't expect to spend more than a few hours assembling this ARF.
Extra 330L EP specs:
Approximate flying weight: 5-5.5 lbs.
More to come...I'll post build info and photos as I make progress.
|May 02, 2011, 01:14 PM|
Airframe arrived late last week, going to at least begin the build this evening. I'll take photos as I go. Some build info already exists on the product page as well as a couple of threads within RCG, so I'll try to fill in the gaps as best as possible. Keep in mind that the recommended motor for this model is a 32-46 size, I'm using a motor designed for a 60 size model, though at a cost of only 2 oz. from the Monster 46. Nitroplanes.com however recommends a Monster Power 60 (probably for 3D), the Turnigy 50-65A is on par with the Monster Power 60 in regards to specs (see link in first post).
|May 02, 2011, 05:08 PM|
That was certainly my first thought. It really put the idea in my head, to be honest. "A 60-sized motor in a 40-sized plane? I like it." Overpowered planes *can* be a handful at times, but underpowered planes usually only fly once or twice (if you're lucky). I always lean toward overpowering. The other advantage of overpowering as that you can scale up to a larger airframe if the smaller airframe happens to end up making a sudden stop in the dirt.
|May 03, 2011, 08:40 PM|
So here's the kit, still wrapped up and in the box. Packaging was well-done, no issues.
Some things that really impressed me about the kit at first glance:
* Plenty of plywood used inside wings, tail fins, fuse, and motor mount area, air frame shouldn't need too much additional strengthening, if any.
* Fuse is made of a fairly rigid plastic instead of balsa, this adds weight, but the plastic is forgiving and seems quite strong.
* Flawless covering job, covering film is thick and plastic-like, doesn't tear or scratch easily.
* Completely removable top hatch for easy access to the electronics
|May 03, 2011, 08:47 PM|
Build Day 1 - Aileron Servos and Motor Mount
Step 1 in the included instruction booklet begins with the Aileron servo installation. I used HS5485HB Karbonite digital servos, more than enough torque for a 5.5 lb 40-size air frame. I prefer to use digitals on the ailerons due to their reliable centering characteristics.
Installation was relatively easy. First, cut the covering film from the square aileron holes, leave some overlap so that the covering film is held down by the aileron installation plate. then, drill the holes in the plastic arms on the installation plate, install rubber grommets to reduce vibration on servo, and screw them in. Nothing out of the ordinary here. Typical aileron servo installation.
Motor installation is covered later on in the manual, but since I have everything soldered and ready to go, I decided to install the motor earlier on. Due to the size of the Turnigy 50-65A motor, I had to drill a small hole in the bottom half of the cowling to get my hex wrench to the bottom screw on the firewall. The predrilled holes fit the Turnigy 50-65A mount with no modifications or stand-offs necessary. I added 3 washers to the bottom of the mount for some up-thrust, and 2 washers on the LEFT side of the mount for the recommended 2° of right thrust.
A couple of things to note - the kit included some 3mm socket head screws and 3mm blind nuts for mounting the motor. I threw those in the trash and went ahead and used the 4mm socket heads as well as the 4mm blind nuts for a more rigidized install, mainly because the motor is quite large and I didn't trust the 3mm hardware to hold up in the long-run. The 4mm socket heads/blind nuts were meant for the landing gear installation, I stopped by the hardware store and picked up 5mm stainless steel socket heads along with nylon lock nuts to secure the gear (later on). I have some hatred toward blind nuts and don't like the fact that they tear into already thin plywood, which I'm sure weakens it. Nylon lock nuts are designed to stay tight even in a situation where there is a lot of vibration, I've substituted lock nuts for blind nuts on many occasions with great success.
|May 03, 2011, 09:00 PM|
Build Day 2 - Tail, Servos, and landing gear installation
Decided to get the tail assembled as well as the rest of the electronics installed. The ply inside the fuse includes precut plywood framing for standard servos. The kit included a metal extension arm for the pull-style rudder, make sure the servo is mounted such the metal arm is centered inside the fuse. The elevator servo installs behind the rudder servo in a similar manner. Fit the servo in place, then drill the holes with a small 1/16" bit. Use the rubber grommets when installing the servos, electric planes do vibrate.
The tail went together easily, the kit includes an aluminum spar as well as small brass tubing for tail installation. I replaced the brass tubing with similar-sized c/f spars as the brass tubes are a bit weak, sneeze on them and they'll fold/crease.
|May 03, 2011, 10:21 PM|
Build Day 2.5 - Landing Gear
The 330L EP kit includes some fairly heavy-duty plastic landing gear, they are thick gauge and feel very strong, I doubt even the hardest landing would break them, the fuse would most likely give out before the gear. As I mentioned earlier in the thread, I bought some 5mm stainless steel socket head screws along with 5mm nylon lock nuts for securing the landing gear to the fuse. The kit comes with 4mm socket heads and blind nuts (as well as washers, etc.) for landing gear installation. I've never been a fan of blind nuts and didn't want them tearing into the already-thin plywood, hence the decision to use thicker bolts along with lock nuts. I've successfully modified other larger (60 size) airframes in the same manner quite successfully.
The holes were easily drilled, though you can see my centering job wasn't quite perfect. The landing gear struts slide right into the main plastic fuse, it's just a matter of inserting them in there all the way and lining up the drill bit to make holes for the bolts.
One other modification - the kit comes with 2" wheels, they are rubber and rather heavy, I replaced them with 2.5" Dubro Lite foam wheels, they fit into the wheel pants perfectly, no modification needed. I fly on a grass field so 2.5" is really the minimum, 2" could have posed problems on landings and takeoffs.
I'm calling it a night, so far I've spent about 3-4 hours assembling this airframe. All that is left is to install the control rods, elevator/rudder linkages, and add some Gorilla Glue/carbon within the landing gear area to beef it up a little. I will also likely add some Gorilla Glue in areas where plywood meets the fuse as it's strong stuff and will hold things in place regardless of vibration. Unlike Epoxy, Gorilla Glue doesn't add much weight, it foams as it cures and remains flexible while maintaining a strong bond.
|May 05, 2011, 09:03 AM|
Day 3 - Control Linkages, Rudder and Elevator
So the included assembly manual does leave a bit to be desired in terms of instructions on how to assemble the linkages, but it does specify approximate lengths (in mm) for the elevator linkage, which is composed of a couple of threaded metal rods, a fiberglass tube, and a set of rubber bullet-shaped "stubs" (not sure what they're actually called) used for alignment of those metal rods and insertion into the fiberglass tube. The rudder (the 330L EP uses a pull-pull rudder) linkages consist of metal wire which I threaded through the included metal rods and tied them using fish hook knots. I substituted 2-56 metal clevis's for the rudder linkages, which happened to thread perfectly onto the small metal control rods (designed for the metal wire to loop through) included with the kit.
Some tips: the rubber bullet-shaped nub designed for the two (y-shaped) control rods needed a little drilling with a small drill bit, it was too tight for the metal rods at first, but using the drill press helped tremendously. The linkage lengths are easily adjustable using the set screws within the rubber nubs, but use the manual as a guide to approximate the lengths of your control rods (in mm) before making more fine adjustments. The rods coming out the back end of the fiberglass tube need some bending in order to connect up to the elevator control horns properly. I used 30-minute slow-cure epoxy to secure the rubber nubs into the fiberglass tube and allowed it to cure overnight before making final adjustments to the control rod on the elevator.
For the rudder, don't pull those metal wires too tight, that puts extra stress on the nylon control horns which can cause them to break during flight. Use enough tension to keep the rudder centered with both metal wires attached. The metal wire should look as pictured below, not too tight, but not drooped downward with too much slack. If you find your wire lines are a little loose, tighten them gradually by turning the clevis and reconnecting to the servo horn. Your rudder should not wiggle back and forth by hand, minimize slop in the rudder by tightening the clevis's.
Overall, the control rods and linkages took the most time (which is typical with an ARF) because of the fine-tuning involved to get things set where I wanted them. The elevator length guidelines in the instruction manual were pretty much right-on, I needed very little length adjustment on those rods after everything was set up as per the instructions. I did some bending of the two rods that hook into the elevator control horns (split to a Y) to ensure the rod would travel smoothly with no binding.
|May 05, 2011, 09:24 AM|
Day 4 - Complete build, radio test, wrap-up
So the final tasks that remain are simple and not at all time-consuming. I still need to secure the canopy onto the upper removable hatch as well as tidying up the wires inside the fuse. Everything else is complete, as well as the radio test. I used the outer-most holes of the servo arms and the 2nd-most inner holes on the control horns to give lots of throw on all control surfaces. The rudder has a ton of throw, while the ailerons and elevator have a bit less (I adjusted mine so that I had more throw than what the assembly manual specified). More throw is better for Aerobatics and 3D maneuvers.
I took photos of the completed Extra 330L-EP kit. As you can see, it's a great-looking airframe, AUW without battery is about 5 lbs. C/G is nearly right on with 2 x 3S 2650mAh battery packs installed in series (I'll post more c/g info after the maiden flight, but I will use the manual as a guideline for initial c/g setup).
Of course, there is that LAST step, the maiden fight. Once the fields dry out and the grass is mowed, I'll take the plane out for its maiden flight. I'll post video in the upcoming days (perhaps a week or so depending on the weather) when I get the chance to maiden the Extra 330L EP.
|May 05, 2011, 10:57 AM|
Build Summary and Review - Extra 330L EP
Overall I was impressed with this ARF kit from Nitroplanes.com. Quality was excellent, the instruction manual was quite helpful, and there were no missing parts. Extra parts are included as well, which was a nice bonus. Only damaged item in my kit was a small nylon clevis, one of the arms were broken out of the box, no biggie to replace it. I substituted hardware as I saw fit in a few areas (mentioned in previous posts), but quite honestly the majority should be able to get by just fine with stock parts.
Novice to intermediate builders should be able to build this ARF with few issues or problems, if any at all. If you're a novice to building RC planes, plan on about 6-8 hours of build time. More experienced builders could probably build this ARF in a couple of evenings, 3-4 hours of build time max.
There are a few important items to note - use blue thread locker (Loctite or Permatex) on any set screws or screws/nuts that thread into metal, the plastic fuse does resonate a bit even with a perfectly balanced prop/motor, so plan on some degree of vibration and take it into consideration throughout your build. Avoid any contact with thread locker on plastic or nylon parts, thread locker will EAT plastic materials and destroy them! Use the rubber grommets on your servos, add thin CA to drilled-out holes after threading the screws into them, this hardens the wood and locks the screw in place. I added Gorilla Glue inside the fuse where the ply was glued to the plastic, this adds some reinforcement without compromising flexibility of the fuse.
The cost of powering the 330L EP is very manageable, this airframe could get by with a 32-sized electric motor, but it would be more limited to Sport flying with the smaller motor. I could've easily gotten away with a 45 or 60 Amp ESC with the 14x8.5 prop I using, but I always buy ESC's rated for a current GREATER than the max current of the motor. The Turnigy 50-65A 400kV motor is rated for 65A continuous power, therefore I chose an 80A Castle Phoenix ESC, which I already had on-hand in my RC electronics stash. Standard servos are the way to go, I went a little overboard using Hitec HS5485HB Digitals, Hobbico standard nylon geared servos are perfectly adequate and go for about $9 at local hobby shops.
According to Nitroplanes, this model is considered a 40-size plane. However, next to my 60-size P-51D Nitro, the 330L EP is not much smaller, though it is a few lbs. lighter being electric powered. In my opinion, the 300L EP is closer to a "50-size" plane. If you lack a larger electric model in your fleet (as I did), the 330L is a perfect addition.
I'll provide more review comments once I have a chance to get some flight time in with the 330L EP, stay tuned...
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