How many planes do you know of where you can take away the fuselage and tail and it flies just as well as the original? ONE, that I know of! HobbyFlite has hit the nail on the head once again with the introduction of their "Electric Flying Wing"!
In a truly great application of versatility, Chris Hill of HobbyFlite brings forth this Flying Wing with many of the same parts as found in their Boeing 747 kit. Of course, the Electric Flying Wing (Ill call it EFW from here to save my typing fingers ) uses the same R-mer foam bead in its molding process that results in a more resilient material than just plain EPS foam. This clever re-configuration of the original Boeing 747 parts results in a nice flying product totally different from its bigger brother. The wings still remain wings, of course, but the left and right stabilizer halves become left and right fins.
You may recall I did a review of the 747 in the September issue of E-zone. Check it out if you havent already.
All one has to do is glance at the sweep on the 747 wings and immediately the thought comes to mind "Say, that would make a neat flying wing". Actually, as crazy as I am about flying wings Im surprised the idea never entered my mind! Chris sent me an e-mail picture and all I could say was "oooooooo".
Upon receiving the box I found it was exquisitely packaged, just like the 747 . Foam blocks were strategically placed and glued to the box walls to ensure safe delivery of all the parts. All loose parts were grouped, bagged, and adhered to the inside walls of the box. As I continued unpacking the box, I once again was amazed at the completeness of the kit. The only thing needed to complete this kit was tape and a little epoxy.
These are the same pictures, just at different zoom levels .
Plus, all the parts needed for assembly, a page of instruction, and a picture reference page.
I pulled the wings out first of course, and I noticed the elevons were already attached, with control horns bonded on as well. Neat touch, I thought. It certainly saves me the time to install them. Then I turned the wing over. Hmmmm, whats this? The servo pockets were already cut out, and very cleanly too, I might add. Cool! Even more of a time saver. Then I noticed the pre-cut aileron extension channels cut into the foam. I had to look at the box lid to see if it said ARF on it! Chris had done quite a bit of pre-work on this kit.
I couldnt help but note other things as well:
- Receiver bay pre-marked
- Motor cavity pre-marked
- Servo Extension wires provided
- Antenna tunnel pre-cut (Neat surprise!) in one wing, also terminates in the R/C equipment bay once you cut it out
- Vertical fins pre-cut to upper wing contour
- Vertical fin locations marked on wings
- CG location marked
- Wheel groups pre-assembled (Another surprise)
- Wheel assembly locations pre-marked
Several unexpected bonuses! Nothing thrills me more than to receive a kit that exceeds my expectations. Also included in the kit were:
- 400 Motor
- Molded plastic motor Nacelle
- Shrink wrap
- Gunther push-on Prop
- Mounting Screws
And the kit price is $65.00. A very nice value.
Other than the fact I was taking pictures and trying to do a thorough review of the EFW, I was sure this plane would go together in an hour. I took longer of course, but even with stopping to take photos, write notes, and ensure I was following the instructions, I doubt I had 3 hours in the assembly of this wing.
Right from the box directly into Final Assembly. Cant get any simpler than that, I suppose!
( shake box vigorously, plane falls out complete )
In a very macro sense, the instructions are essentially:
- Join wings
- Cut a little foam
- Add motor
- Add servos
- Tape here and there
- Put wheels on
- Balance and fly
Sure, its not that simple, but theres only one page of instructions and there isnt that much to do. I spent more time downloading these pictures in this review than I did in actually assembly of the EFW.
Theres really not much point in going through the instructions in detail during this review. Theyre easy to follow, and youll get a set if you buy the Wing. But I will add some hints where I think it made assembly easier.
First off, once youve joined the wings and need to start cutting into the foam, its a good idea to hold the foam up to a bright light to "look" through it. This way you can gauge the overall consistency of the depth of the cut, plus prevent cutting clean THROUGH the foam. In this photo you can see the receiver and battery bays.
You can also note the pre-cut aileron extension wire channels. You cant see it in this photo, but the receiver antenna tunnel is in the left wing as well.
Here are a couple of shots of the bays after cutting:
After the bays were cut, I installed the extension wires and servos.
Once both servos were installed, along with extension wires, I ran the receiver antenna down the tunnel in the left wing panel. My receiver was just slightly larger than the bay, so it held itself in nicely for the next step, which was taping. The servos were installed with control arms straight up. The elevons were "reflexed" to the prescribed amount specified in the instructions, and the control wires attached.
Now it was time to reinforce the wing with some tape. Follow the steps provided in the instructions, but I cant make it any more clear DO NOT WARP THE WING IN THE PROCESS! It helps to hang the center part of the wing off the end of your bench when you are taping either the top or bottom. The center part is thicker, and can cause you a warp right away if the surface of the wing isnt flat against your workbench. When taping the top side, it pays to hang the little flap mechanism nacelles off the edge as well. Just keep the wing flat and dont put any tension on the tape. You should be okay if you are careful here. But, the tape does come off in case you mess up.
Once wing is taped, you can add the landing gear. Youve already made cutouts for the gear by this point, so dont forget to cut the tape away before adding them (wing tape is not shown in picture).
Or you may choose NOT to add the landing gear. The flanges on the plastic holders are wide enough that Im sure they could just be taped in place without permanently gluing. I just used double stick tape to hold them in place for pictures youll see later, and taxied around the basement without any problem. This probably wouldnt hold up to the rigors of a crosswind/sideways landing, but it wouldnt take a whole lot of strategically placed tape to address that problem. These little buggers are neat, though! They are pre-assembled just like you see them in the picture.
And better yet, consider the weight. Its hard to see in the picture but my scale shows all three gear assemblies weighing ¾ of an ounce total. Thats pretty light for mains and a nose gear.
Heres the final shot of everything assembled and ready to go!
Now I recognize some of you may be scratching your heads and wondering when I put the motor in. Theres a reason for that! I have a couple of ulterior motives here Ive always wanted to do a multi-motor flying wing, and this will be a testbed (after the review of course!) for a couple of multi-motor experiments. I want to try twin 400s, twin 280/300s, and several iterations of single and double ducted fans. Look for the results next month in E-zone. Where I diverted from the instructions was in the motor mounting. Heres a few shots of what the instructions INTENDED for you to do.
I didnt want to glue the nacelle in place because it would complicate my future experiments. So I made up a couple of plywood "sandwiches" and used aluminum clamshell mounts to hold the motor. This allowed easy installation and removal of the motor without any significant weight gain or loss.
Heres a completed shot of the EFW with my removable mount.
Between long work hours lately and a spell of bad weather, a test flight was difficult to arrange. Even worse I live far enough out from civilization for UPS to call us "Remote Delivery Location". Finding some asphalt for an ROG takeoff wasnt going to be anywhere near as simple as just flying in my back yard. So I opted for the grass field, hand-tossed approach. I just had to make sure I avoided the horses. They dont get mad, they get even .
So I left the gear off. However, I initially feared the lack of protection the gear afforded to the under-slung radio equipment, so I hogged out a chunk of blue foam and made a combination radio protector and throw handle.
Later on this proved to be unnecessary, but I wasnt taking chances since my receiver would be the first thing to hit the ground!
I then charged a 7 cell battery pack (600AE), taped it in place, and added the blue foam protector. I checked the reflex amount of the elevons again, and verified proper control throw direction. All ready to go, I tossed it gently without the motor running and it settled very nicely into the grass several feet away.
It glided so well I almost powered up immediately, but I decided to wait. On the second flight, I tossed it out and then went to half throttle. That was about all that was required. After gaining altitude, I trimmed the ailerons and elevator and went directly to the task of flying it. I added full power, and climbing out was not a problem!
The first flights were pretty standard, no surprises. I did take it easy just to make sure everything was working well, but later on I started horsing it around quite a bit. It will roll, and it will loop, and it does both of those maneuvers reasonably well. But where I had the MOST fun was just slow-flying it around my yard 2-3 feet off the ground. It was very easy to control in this fashion, and I was having a blast. I did lazy figure 8s, circles, and an occasional attempt to see how low I could keep the inboard wing to the ground without touching. A very fun plane indeed!
Mine weighed in at 15 oz, and with 450 sq. inches of wing area the wing loading was 4.8 oz per square foot which really qualifies as a "floater". The neat thing about it was that there was plenty of power and it would climb nicely. Im contemplating putting a Speed 280 on it for my December "Forum 400" column experiments. This will take 3-4 ounces out of the wing and Im sure it will still fly fine. My intention for doing this is to maximize the "slow flyer" aspect of it. And just for kicks, too
But now for a good news, bad news story. The bad news is I stuffed it into the ground REAL hard. The good news is it survived! Had I not broken the Gunther prop I would have been back in the air almost immediately. The cause of the crash was two-fold. The first fault was mine perhaps for entering a 45 degree power dive and KEEPING it there. The second fault perhaps was the use of too-thin control wire going from the servos to the control surfaces. I recommended to Chris that he increase the diameter of the wire offered in the kit because for "up" control the servos are pushing on the wire. I had the Wing going so fast that the control wires bowed and I didnt have any ability to pull out of the dive. Man, it hit hard. I originally doubted the durability of the R-mer foam bead material, but after the severity of this crash Im a believer in it. Like I said, had I not broken the prop I would have flown it again immediately. (I had only double-sticky-taped the rudders on, so that helped too).
And in Conclusion
Ive been working on this review for over a week now, and still do not have suitable weather nor a suitable concrete runway to evaluate the gear for takeoff and landing. They will only add ¾ ounce to the all-up weight, so it wont be significant. The gear isnt steerable, but as fast as the Wing accelerated when I was playing around with it in my basement Im sure take-offs will be very short and directional control wont be an issue.
Recognizing that I have an earlier version of the instructions, there were a few things not listed. Chris is sending me a Version 2 of the instructions, but I havent received them in time to finalize this review so Ill have to do a follow up. Control throws werent specified, but I ended up flying mine at +/- 3/8" travel for elevator function, and +/- ½" for aileron function. From an e-mail conversation, I understand Chris is changing the gear location slightly to allow better rotation or higher incidence at takeoff. Motor angle is not specified, but its assumed the user will place it perpendicular to wing chord line. I angled mine with prop low and brush end high, for a little "forward pitch" under power. I liked it this way. I have the motor parallel with the top surface of the wing at the trailing edge. Anywhere in between these two angles would be acceptable.
A couple of other tips: Oil the wheel shafts and youll find a marked reduction in friction. If theyre still a little tight then run them in by using a soft buffing wheel on a Dremel tool to spin them. But oil them first. I only had one that was a little on the "sticky" side. Also, when cutting out receiver and battery bays, dont take out any more foam than absolutely necessary. The center section is the thickest part of the wing, which is good because its taking the greatest brunt of the bending load. Taking too much foam out in that area could reduce your overall strength. There is a "bridge" of foam that remains in-between the receiver cutout and the battery cutout; make sure you maximize this to the greatest extent that you can. I didnt have any problem with this, but it was something I would caution someone who hasnt worked with foam very much.
Heres a write-up on the Electric Flying Wing by Tony Frackowiak, who also provided input and testing along with Chris on this plane. Tony has the following credits to his name:
- Team Futaba
- USA Pattern Champion
- USA Team Member
- NASA R/C Research Pilot & Technician
Heres his input:
I've really had a blast with my Wing! It draws a lot of attention at the flying field, as it looks just great in the air. It's a very simple plane to build and operate, but it's performance is impressive for the cost. The Wing is really a terrific break from the complex models I work on everyday. A great "Bang for the Buck" model!
Wouldnt you know, I pull mine out of the box, put it together and leave it white. They look even cooler all prettied up, dont they? Heres some pictures Chris sent me:
HobbyFlites Electric Flying Wing is a winner in my mind. The strongest points I saw were the high degree of pre-work, the completeness of the kit, and the flight qualities. It climbs very well, goes pretty fast, yet backs down to a crawl for slow-flying. The only suggestion I would make is to use a thicker linkage wire between the servos and elevons.
Buy one, its a keeper!
Watch the December Forum 400 column for alternative power packages I intend to try on it Im hoping to have a good time playing (Or should I call it "experimentation"?)
Keep warm till the snow falls,
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