On final approach.
|Wing Area:||751 sq. in.|
|Wing Loading:||19.7 oz/sq. ft.|
|Servos:||5 Standard servos|
|Battery:||Two TP 3S2P 4200 Prolites in series|
|Motor:||EFlite Power 60|
|ESC:||Castle Creations Phoenix 80|
|Available From:||Horizon Hobby or Local Hobby Shops|
The Harrier 46 is a non-scale lightweight designed aerobatic ARF...ideal for electric conversion! This article describes the steps required to convert the Seagull Harrier .46 to electric power...specifically, using the E-Flite Power 60 brushless outrunner. These techniques could also be used to modify most glow ARF planes to use electric power.
The basic airplane assembly was previously covered in the RC Power review with an Evolution .46 engine. To summarize that article, it says....
Horizon Hobby has a winner in the Seagull Models Harrier 46! The plane is quick to assemble, fun to fly, and looks great. I really enjoyed assembling and flying the Harrier 46. I was pleasantly surprised at how well the Evolution .46NT engine performed in this plane with the APC 12.25 x 3.75 prop.
Items used for conversion:
An E-Flite Power 60 motor provides the power for this conversion. This is an outrunner brushless motor. This means that the motor magnets are mounted in the can portion of the motor and the entire can spins while the stator containing the windings remains in place. The Power 60 is named such because it can be used to replace a .61 size two cycle (or .91 size four cycle) glow engine.
The accessories included with the motor are:
The 4-40 bolts and the spinner nut were not used in this conversion.
The first step is to determine the distance to mount the motor from the firewall....calculated to 1.5". The instruction manual provides the distance that the propeller back-plate should be from the firewall. By subtracting the length of the motor from this distance, I arrived at the distance required to support the motor from the firewall. In this case the standoff distance was 1.5 inches.
My favorite method for mounting outrunners is to use large bolts through the radial mount and nylon spacers secured into the firewall with blind nuts. For this conversion I obtained four sets of a 2” long 10-24 bolt, a 1” nylon spacer, a ˝” nylon spacer and a blind nut to mount the motor. This hardware can sometimes be found at a home improvement store like Lowe’s or Home Depot but I usually find a better selection of items at a dedicated hardware store such as Ace or True Value stores.
The battery used in this conversion consists of two Thunder Power Prolites in a 3S 11.1V 4200 mAh configuration that are joined in series to provide a 6S 22.2V 4200 mAh pack for the motor. Anderson Power Poles are convenient for joining batteries in series because the connectors are genderless. This allows two or more packs to be joined in series without the need for a special harness.
A Castle Creations Phoenix 80 was used as the ESC. Since the built in BEC cannot be used on a 6S configuration, a UBEC by Kool Flight Systems was used to provide 4.8V to power the receiver and servos. A receiver battery could also be used instead of the UBEC.
NOTE: I also enlarged the holes in the radial mount to accommodate the larger bolts.
The cowling could also have had some additional holes to allow for more cooling air. So far I have not found a need for additional cooling despite flying on 100 degree days (37 degrees C).
I screwed the radial mount to the motor and bolted the assembly to the firewall. This allows the motor to be mounted maintaining any offsets (thrust angles) that are built into the firewall. It also makes it easy to adjust the offset by adding washers or shortening spacers as necessary.
The cavernous fuselage provides ample room for mounting the batteries.
I used some basswood beams to create a battery tray in the front section of the fuselage. In hindsight I wish I had notched the formers to accept the beams and provide some additional gluing surface. However the beams are plenty strong as installed. A plywood plate was cut to fit between the spar tubes and secured into to place with epoxy. This setup allowed me flexibility in obtaining the recommended center of gravity by moving the batteries in the fuselage.
The included spinner had an interesting feature. The plastic was thinner in the area around the propeller openings. This made it very easy to enlarge the openings with a hobby knife to clear the wide electric propeller. I did find that the spinner would not go over the included spinner nut so I picked up an 8mm by 1.25mm nut at a local Lowe’s.
The completed plane sits ready for flight. The electric conversion is more powerful than the glow version was yet the weight is almost the same. The Glow version weighed 92 ounces without fuel or decals. The electric version weighs 102 ounces ready to fly. Since the glow version held about 8 oz of fuel and was lacking several ounces of decals in the review that ready to fly weights were almost exactly the same with a full tank of fuel.
The plane is fantastic! It jumps in the air and goes ballistic. It can roll faster that the eye can follow and fly either very large loops or very tight loops.
The light wing loading makes takeoff and landings a non-event. The plane tracks straight on take off rolls and only requires a small amount of elevator to become airborne.
The large thick wing allows the plane to come in slowly on a predictable glide path.
This plane flies great for either the Sunday sport flier. It can be flown by most sports pilots when reasonable control throws are used. When the throws are cranked up the plane becomes a blast to fly. The transparent wing looks great but it does make it difficult to determine the plane's orientation when flying. A few simple stripes on one side would really help. The plane is capable of most 3D maneuvers. One thing that I found made hovering much easier was to add exponential to the throttle channel. This made the throttle less responsive around the half power and allowed me to enter a hover with much less effort. I handed the controls over to several more capable pilots that I am at 3D maneuvers. Although the plane could perform most of the maneuvers, it requires more trimming and setup that some other similar planes. Ben Fisher of 3D Hobby Shop suggested that it did make a very good trainer for learning Harriers.
Many people flying smaller planes are concerned about buying large batteries for a conversion like the Harrier .46 or a Hanger 9 .60 size warbird.
However if you are flying any of the E-Flite Mini series such as the Mini Ultra Stick or Mini Edge, you may already have the necessary batteries.
By standardizing on a battery such as the Thunder Power 3S 2100 Prolite packs you can use these as modules to expand the types of planes that you fly.
One pack can be used in any of the E-Flite Mini series or the Seagull EP Extra 300.
By placing two of these packs in parallel, for a 3S2P 4200 mah battery, you create a pack that can be used to fly a 25 size plane such as the E-Flite Ultra Stick 25E or J-3 Cub 25.
Four of these packs can be joined in a 6S2P configuration to power a .45 size 3D plane like the Harrier .46 or a .60 plane such as one of the Hanger 9 .60 size warbirds or sport planes. You can make your own harnesses or buy ready made ones such as those shown above.
The electric version is noticably more powerful than the glow version that I reviewed, yet the planes are almost identical in weight.
The electric version has just under 2 bhp while the glow version was probably closer to 1.5 bhp at the propeller. This gives the electric version the edge for performance and ease of use. Also there is no mess to clean up after flying. The disadvantages to the electric setup are initial start-up cost and total flight time. On the 4200 mAh battery a flight of about 20 minutes is possible but it will take an hour to recharge with most chargers, or a second pair of batteries would need to be purchased. Thunder Power has recently introduced a charger that is capable of charging these batteries in about one half hour. This would double the amount of flying that one set of batteries could provide during the day. The glow version can be refueled in only a couple of minutes.
NO! This plane is not designed or intended as a trainer. Even though on very reduced control surface movements it could be a second plane, it should really be a third or fourth airplane. Although it is very easy to take off and land, it is capable of very abrupt maneuvers with extreme control surface movements and the light structure may not hold up to learning mistakes. Additionally, it has no self-righting characteristics.
The Seagull Harrier .46 appears to be designed with electric power in mind, and the conversion was easy and extremely successful, ending with MORE power than its glow brothers! The large open fuselage and light structure make the electric conversion easier than setting up the glow powered version. Some people have criticized the landing gear as being to soft. However I discovered a benefit to the soft gear. The soft gear takes abuse and bends rather than transmitting all of the loads in to the fuselage and results in much less damage to the plane when mistakes happen. So I was glad that the gear was soft. A very strong gear wound have likely resulted in a total loss of the airframe on on occasion. This plane makes an excellent conversion and the Power 60 motor is well matched to the airframe. A big thanks to Ben of 3D Hobby Shop for helping with the video of the Harrier hovering and performing harriers!
Towards the end of the review I was able to switch from a 72 Mhz radio to the new Spektrum 2.4 Ghz DX7 Transmitter and AR7000 Receiver. The DX7 was easy to program and within a few minutes I had the flaperons available as normal, flaps, or spoilers! It also was very easy to set up mixing for the dual elevator servos. The DX7 provides an impressive feeling of being connected with the plane. The low latency and servo synchronizing features that it offers are very impressive, and unlike its little brother, the DX7 has full range like any 72Mhz system. Look for a full review of the DX7 system in the near future here on RCGroups.com!
This plane makes an excellent Sunday/Sport Flyer plane. While the plane is capable of 3D maneuvers, a hardcore 3D Pilot may find other planes more satisfying. Horizon is currently offering this plane for under $100 and it is certainly a bargain at that price.
Thanks for noting that I didn't crash the plane at the end of the vid! The crasher shall remain anonymous.
The wind blowing about 80 miles per hour kept us from getting decent hover and harrier footage, but there are some vids of smooth harriers in the various threads about the airplane on RCG. The plane really does excel at that maneuver.
I enojyed flying it, even with the howling wind. It had good power and lots of control authority.
I have been wondering this for a while. With the advent of Lipolys and significantly more powerful motors is there really such a thing as a bad candidate for conversion to electric power? I say this because I remember 5 years ago and more when we really had to replace wood with lighter wood and add extra lightening holes etc. but from my own planes it just seems like I am always overpowered with my electric sources. Just wondering. Either way I enjoyed the article and I especially enjoyed the music track that you put with the plane. It didn't replace the sound of the plane and it didn't detract from the flying at all. Often that is a rare thing.
Thanks for the comments.
I have been converting glow planes for about 20 years. While it used to take some research and luck to get a conversion to fly, today almost every kit and ARF can be easily converted with little to no weight penalty and often better power/weight ratios.
Is it really fair to compair the glow version you powered with a weak 46 to an electric setup for a 60 motor and 6s?
You might want to try an Irvine 53 or other stong motor on the glow version, or even an actual strong 60 for a comparison.
I would certainly be more interested in the comparison then.
Good article gwh, thanks.
I recently electrified a Seagull Spackwalker II ARF using the same motor (Eflite 60), an Align 75a esc, koolflight 35v bec, and 5s1p 3700 Evo20 flight pack. I'm also using a DX7 radio and am using the digital servos included with it (DS821's).
Used a similar spacer motor mount but because the Spacewalker design is a bit different, I only needed ~ 1/2 the spacer length as you did. I used some hard, black neoprene tap washers from a plumbing shop plus a 2mm thick metal washer on each end making a neoprene sandwich! When tightened up evenly and loctiting the bolts to the blind nits, this is a very secure, stable mount. The neoprene also has the advantage of getting rid of any and all vibration (not that there is much anyway).
The CG worked out fine with the battery pack mounted on a ply floor I glued in the nose where the fuel tank would have been and the pack sits just before the elev/rudder servo tray.
The only changes I made to the stock kit was to pin the hinges (although the box said they were already safety pinned and installed, they were not). Also, I scrapped the small stock wheels and spats and went to larger 3 inch wheels dubro light weight ones for better ground handling on grass strips. I also scrapped the cheap plastic spinner and used a better one with an Al back plate.
The other thing I noticed was that the wings were not well balanced a needed ~25g of lead on one wing tip. You might want to check yours since this may be why you are dropping a wing in a harrier.
The total weight, with batteries, is 3.2 kg (7 lb). With an APC-E 15x10 prop this is a very acrobatic, and fun to fly plane. Full throttle pulls 42 amps and 850 watts of power, measured with my on-board Wattsup meter. This is not a 3D machine, but it will hold a full throttle hover for ~5-10 sec. It is a very good acrobatic plane at 1/2 throttle (~20-25 amps) and is a real pussycat to fly on low rates. I did find that I needed to use some JR super servo long arms to max the aileron deflections to get as fast a roll rate that I liked. I also moved the CG back ~ 2 cm to make the plane a little more responsive, but I would not recommend that beginners try this!
Depending how hard I fly it, I'm getting 8-9 minute flights using 26-2800 mahr of battery capacity which is well within the 80% lipo discharge rule. All temps after ~8min runs are just around body temp (97-100 deg F).
This was my first large electric conversion and it was very easy. I normally fly smaller 3D electric planes and large electric heli's (which is why I have a lot of 5s1p 3700 evo20 packs, I use 2-4 of these packs in my heli's). The Spacewalker II is a great, low stress, but lots of fun, plane to fly. Loving it!
Edit; I'll add this to a new spacewalker thread to make it more accessable for others to comment on this specific model in this forum.
Last edited by TomC; Mar 20, 2007 at 07:59 AM.
Im converting my Seagull PC9 RAAF colors to electric using a Turnigy G60(500)
I just have a few questions;
1. Props, im lead to believe that props for Glow engines are heavier than Electric ones. I was using a 10x5 Master Airscrew 2 blade prop. The most efficent prop for me is 13x8, but getting close to the ground. Is there such thing as a electric prop and a glow prop?
2. I purchased a HobbyKing Red Brick 100A ESC, is there such thing as an ESC that is too big??? I have yet to choose the battery required. Was thinking of running a few of my 3 cells in series until i find a battery that suits.
Cheers in Advance
ESC cannot be too big from a current handling point of view - it can't force any more current into the motor than it demands. The only issues are cost, space and weight.
2 x 3S in series is fine, as long as the capacity is enough to take the current. Expect over 50A with a 13x8 on 6S with that motor. BTW, if 13x8 is tight for ground clearance, a Master Airscrew 12x8 3 blade will do just as well
BTW, posting this question in a 6 year old review thread about another model is not the best idea - you're not going to get much passing traffic. Also, given the range of models and manufacturers, either full details of weight, span and wing area or a link to the model always help a lot.
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