I have liked the looks of the Multiplex Easy Glider since I first saw it, with the eliptical upswept wing tips and the ailerons. Word was that it had a higher performance airfoil. When I saw George Joy fly one at the Arizona Electric Festival, and learned that it was flying on the stock motor / gearbox setup, I was convinced to try one.
This Easy Glider was first bought as a "RR" version kit- "Ready For Radio", from George Joy, one of the vendors at the Arizona Electric Festival in late January of 2006. I had other materials with me to assemble it and put the aircraft into the air quickly.
The tail group was glued in place, the radio receiver was installed, and [after trying one flight with an older tired 8 cell NiMH battery pack, which seemed too under-powered], two new 3S 1500 mAH 15C LiPoly battery packs were bought from Dymond (who also had a vendor booth set up at the Electric Festival.) Deans Ultra Connectors were installed on the batteries and on the ESC lead. Some of the flourescent orange trim tape was applied to improve visibility while the sailplane was riding thermals at higher altitudes; some of this was completed before the first flights in Arizona during the last day of the Electric Festival. The rest of the trim and additional orange were added later. The canopy was painted blue with Krylon H2O spray paint (which is foam-safe and waterproof once dried.)
Wing Span = 72"
Fuselage Length = 44"
Wing Area: 4.5 square feet [FAI]
Wing loading range: 7.2 to 7.85 ounces per square foot
Flying Weight : ~32-1/2 ounces when flying with the 3 cell 1500 mAH LiPoly pack; 35-1/2 ounces with the 8 cell 2/3A GP 1100 maH NiMH pack
DYMOND MAX 480 brushed can motor, mounted to the stock Multiplex gearbox
Propeller: 11x8 CAM Auronaut folding propleller set collet adapter & spinner
ESC: Multiplex X16 ESC for brushed motors
Battery : 3 cell 1500 mAH LiPoly 15C pack; or 8 to 9 cell GP 2/3A 1100 mAH NiMH custom flat pack
4 Multiplex Servos (pre-installed in RR version): Rudder, Elevator, and two aileron servos
Berg 5 Receiver; set up to allow Spoileron deployment for landings
Transmitter used: Airtronics RD8000
The photos below show my Easy Glider on May 19th, 2006, with the 11x8 CAM folding prop and the added fluorescent trim for better visability.
A minimum of the trim decals which came with the kit were actually used to dress up the aircraft; I was more concerned with increasing the in-flight visibility and adding some landing protection durability.
The underside of the fuselage was given a layer of 2" wide nylon filament tape before the first flight to minimize landing 'rash' from the paved runway landing area used in AZ. Later, after using a fine grit sanding sponge to smooth away the remaining molding vent 'bumps' on the surface of the foam, I added all of the fluorescent orange tape to the belly and the tail, and added more orange tape to the underside of the wing tips- both to increase visibility at altitude, and to add a more complete anti-scuff coating under the wing tips where they can touch on landings. I fly a lot of less than ideal landing areas, so providing the scuff protection to the underside makes good sense.
On the afternoon of March second, I had some time available, so I took out the Easy Glider to do some thermal hunting. The hay meadows near home along Fourmie Creek road were snow-free, and the sky had scattered clouds. Temperature by mid-afternoon was roughly 40 degrees, and there were only light intermittent winds being produced by air flows into the thermals that were forming- good winter thermal flying conditions. I set up my bag chair so I could settle in comfortably to look up at the sky with a place to lean back and rest my neck, and launched the E.G.
The stock 9.5 x 6 folding propeller which comes with this aircraft allowed the sailplane to climb out reasonably well on the three cell LiPoly battery pack when flying below 2000 feet elevation in Arizona. In Colorado's 16% thinner air up here at 10,000 feet elevation, however, the climb can be described as 'moderate' to 'marginal'. When the stock 370 can motor was new It was adequate for non-competition relaxing thermal flying, although climb runs are long & gradual. The question remains as to how much power the stock motor can actually handle without deteriorating in performance when attempting to prop up the setup for more agressive climb.
[NOTE: See later comments about motor replacement / upgrade, and new folding propeller to match.)
I had the balance too far to the rear on the first launch this day; while still flyable, control response was overly sensitive, and when put in a dive, it would stay in the dive and begin to tuck... but I flew several softer thermals and one "boomer" thermal well up towards cloud base, and worked the sky for about a half hour before landing to readjust the battery pack position to bring the ballance forward. Upon re-launching with the same battery, the handling was less sensitive, and the E.G. was flying well.
This sailplane does 'indicate lift' well; I'm still playing with finding the 'perfect' balance point and trim settings for different flight modes. The airfoil reminds me somewhat of the SD6060, with the undercamber just in front of the trailing edge; it handles well over a wide speed range.
I flew the Easy Glider for close to two hours on this afternoon before calling it a day. I had changed battery packs about half way through, but from the recharge time, neither pack was discharged much more than roughly half way. The stock motor / gearbox is efficient from the standpoint of power consumption.
I would expect the Easy Glider to handle well in slope lift- especially on light lift days when the slope ships with higher wing loadings are unable to stay up. At 32-1/2 ounces with the light LiPoly battery pack, it is light for it's size / wing area for slope flying. With the heavier battery options onboard it would have better forward speed capability and penetration in slope flying conditions. It will be a fine sailplane to take along to the slope, to hunt thermals and "Slermals" - (slope thermals) before the slope lift winds come up to speed.
ONE DESIGN MISS: The two light duty plastic canopy latches inside the fuselage appear to be the one design point that will / did fail first- they are in an area where aileron servo and battery wires can get accidentally caught in them each time the aircraft is assembled or the battery pack is changed out. The slim springy plastic fingers can easily break off if and when this is inadvertently allowed to happen. Before long, another canopy securing latch needed to be devised.
I did do this canopy latch modification!- see the photo below. I cut a notch and installed a small Neodymium super magnet in the foam on the alignment 'hump on the fuselage, and cut a matching cutout in the canopy mateing surface in the canopy, where I then super-glued a large thumb tack. Latch-up is solid and positive, while canopy removal is quick and easy.
I then removed the remaining plastic pieces of the original non-servicable canopy latch setup, which leaves more clearance for battery & servo wires with less on which to get fouled / hung up. I'm more than happy with the result of this quick modification!
I just completed the stock can 370 motor replacement / upgrade project, replacing it with a longer and more powerful 480 can motor! (My stock can 370 motor was acting 'tired'... time to do this project!)
I used a zona razor saw to cut off the top of the nose section at about 5/8" forward of the front edge of the canopy opening, down into the cooling air intake vents. I decided to use a DYMOND "MAX 480 Nighthawk" Motor - a $15.95 priced 480 sized can motor, which I already happened to have on hand, to try it to improve the climb performance of my Easy Glider.
I found that the screws mounting the gearbox to the stock can motor were loose when I removed it from the aircraft. (If you are flying with the stock motor / gearbox, you might consider checking this, check the gears for wear, and possibly re-grease the gears while you have it out.)
After confirming that the replacement motor matched the fit in the gearbox, I used my gear puller to pull the drive gear from the shaft of the stock can 370 motor, and pressed it onto the MAX 48 motor's shaft using my drill press, matching the seating depth to the original.
I remoived the flux ring from the outside of the motor for use with the gear drive- ( just my approach; I did not test it both with and without the flux ring.) I then assembled the motor to the gearbox (with some new silicone grease on the gears) and mounted it into the nose of the E.G. fuselage. I cut away more foam in the motor cooling vents.
Cooling air in ther stock configuration only comes in to the rear 1/3 portion of the stock can motor, leaving the forward 2/3rds of the motor in stagnant air. If you are flying in warm weather at anything approaching the maximum recommended motor current of 16 amps for the stock can motor, you can expect it to get quite hot. Enlarging the cooling air intakes & opening them farther forward to cool the entire motor would be a very good idea on ANY Easy Glider.
I also enlarged the cooling air outlets under the wing. I used a bit of hot melt glue to locate the gearbox flange in place in the nose. Then I replaced the foam piece on top, holding it in place with nylon filament tape; that way, it's easy to remove it again if needed, but is solidly held in place.
In the photos above, you can see how the cooling air intake openings on either side of the nose were opened well forward (by cutting away more foam) to offer better cooling for the motor.
Next, I needed to find a folding propeller that would match up to this new motor/ gearbox setup; this motor is a different wind, so what worked on the stock can motor no longer applied. The one shown in the photo above- stock blades in an aluminum mid-part- was not drawing enough amps / watts on my meter, so I knew I needed more power input to produce the thrust I was looking for. I tested several sets of blades & prop sets, and after doing some test flying, I've ended up using some Aeronaut 11x8 blades in the setup above. This prop setup performs very well when flying the 3 cell 1500 LiPoly battery. Performance is more marginal flying on an 8 cell GP 1100 pack, partially due to the lower voltage, and partially due to the increased flying weight. A 9 cell GP 1100 mAH 2/3 A pack may be tried to see how it performs. At tihs time, the climb and gliding characteristics seem to be optimum with this motor/gearbox & 11x8 folding prop when flying light on the 3 cell LiPoly pack.
I set up and tried a 12x10 Graupner SPEED GEAR folding prop; it overloaded this motor on the 8 cell GP 1100 mAH NiMH pack, and performed poorly, so it was removed after the test flight.
To enlarge a collet type prop adapter to fit the odd size of the Multiplex gearbox's output shaft (which is somewhere close to 3.45mm diameter), a 3.2mm / 1/8" collet needs to be carefully drilled out in two steps- first with a #29 drill, and then a #28 drill, to end up with the required .136" I.D.)
NOTE: I had tested an Energizer AA pack, but the cells will not deliver the current needed without a severe drop off in the voltage level... I am now using the Energizer AA cells as a new 2500 mAH transmitter pack instead!
I'll still be able to use various battery options- the 3 cell LiPoly for light weight flying, or an 8 or 9 cell NiMH for only slightly higher wing loading/ better penetration on windy days or on the slope- all at a modest cost. The INTELLECT BATTERY 1400 mAH 2/3A cells might be another great choce for an 8 or 9 cell pack. They are available from www.CheapBatteryPacks.com as either loose cells, or built into custom packs at a reasonable cost. The CBP 1250 2/3A cells, at about $2.25 per cell, might also be a good choice in an even less expensive cell.
UPDATE 05-24-2006: Battery test flights
I flew this motor / prop combination some more; while climb performance is now good on the 3 cell LiPoly, the lower "9.6 volt" voltage offered by the 8 cell GP 1100 mAH NiMH pack still leaves the performance weaker than I'm satisfied with.... So I converted one pack to a 9 cell pack (- I had an extra new cell on hand-) and did a quick test flight last evening. At the nominal rating of 10.8 volts, the climb is much improved! Balance is still an issue; the pack needs to be rebuilt into a shorter pack of three side by side sticks of three cells, so that the weight of the battery pack can be slid further to the rear for optimum balance; in the present configuration - (two sticks of four cells with the 9th cell crossing the back end of the pack) it's too long, with the weight / aircraft balance a bit too far forward for optimum glide.
At this time, I still prefer the way the Easy Glider handles in thermal flying conditions (With the MAX 480 motor and 11x8 CAM folding prop) when flying on the 3 cell 1500 mAH LiPoly battery pack. A 9 cell 1400 mAH NiMH Intellect Battery pack, custom built in the 3x3 layout configuration, would definitely be worth testing, however.
Continuing flight reports on the performance of this MAX 480 motor and testing of suitable folding propellers & batteries will be posted as flight testing conditions and time allows.
I also recently ordered this inexpensive brushless Outrunner motor & ESC combination: only $32.99 + $5.00 shipping! If / when I install this motor in my E.G., I'll add a motor mounting plate / bulkhead in the nose & remove foam for clearance as necessary, so that the motor outrunner bell is just in front of the original foam, out in the cooling air flow. (By doing that, the air flow through the inside of the fuselage will be used primarily for cooling the ESC and battery pack.)
[Note: Here's the content of an email, [now slightly edited for clarification] which I wrote to MultiplexUSA / HitecRCD on 05-22-06:]
I bought an Easy Glider RR earlier this year.
Recently, on my recommendation, a friend Jim also bought one. We found the elevator servo gear train had locked in one direction of travel before the aircraft setup was even completed; we managed to free it [only by forcefully moving the servo arm], and the servo would rotate through full travel, but it was extraordinarily noisy as far as the internal gear train noise.
When ready to do a test flight on Jim's EG, we found that the elevator servo gears had once more locked up. This is not due in any way to flight damage, (as there was none possible by this time- it had not yet been launched!), no wires were in the way... it was an internal binding of the gears. I told Jim that we could not trust this servo! If it did this in flight, it would lead to a crash, posssibly destroying the aircraft. So we immediately removed that Multiplex "TINY S" servo, and put a HITEC HS-81 in it's place.
I later opened the servo to look for irregularities in the servo gears, but could not see anything obvious which could be a problem; but the servo is very noisy running on the bench on my E-Sky servo tester, too, and so it continues to display the symptoms of poorly shaped / irregular gears, and can not be trusted to not lock up again.
There's more to this TINY-S servos with irregular gears / gear train lockup story... it's not just one servo!
I've been flying my E.G. RR occasionally since late January, when I bought it, assembled it in short order, and flew it at the Arizona Electric Flight Festival. Just last Friday while flying mine, while it was up in the air, I noticed that the rudder servo had ceased to respond. Fortunately, it was close to a centered position when it locked up, not out towards the limits of travel, so I managed to land it by flying with the ailerons & elevator without any problem. When I lifted the canopy, I found the servo arm 'locked up' in the same type of binding gear train as the previously mentioned TINY S servo had displayed on Jim's elevator. By trying to move the servo arm by hand, I managed to free the servo gears so that they would once more cycle through the full range of travel... Again, there has NEVER been a hard landing on my Easy Glider- it's in pristine condition, and I'd like to keep it that way.
I'm suspecting that this may not be the first time that you have heard of this TINY-S servo gear train binding; If an elevator servo locks up in flight, destruction of the Easy Glider is a virtual certainty!
Are there FOUR replacement servos (or at least 4 sets of better running servo gears to fit the red TINY S Multiplex servos?) which you could send to us immediately? I don't trust these servos as they were built into the RR kits... I'm considering my Easy Glider 'GROUNDED' until this defective servo situation can be effectively rectified.
[Also, I'm curious as to whether there are any reported issues with the small red servs used in the wings of the RR versions for aileron control.... please advise.]
I wanted to contact you on this critical issue before posting my concerns and warnings to the RC Groups Easy Glider discussion thread; I'm sure that this situation of defective servos / gears is one which you will want to promptly rectify. I will post this email to my web site Easy Glider page, and will promptly update it with any reply and further information which you can provide.
Bruce K. Stenulson
I tested this servo further on the bench while it was still in the caircraft; the servo gear train can be heard to bind in five places through the range of travel; from this observation, I would surmise that there's one of the gears which makes about 5 revolutions which is improperly mating with other gears- it may have an irregulearl formed area of teeth on that one gear, which is resulting in the binding and lockup.
While I was slowly moving the control stick on my transmiter from center, to full left, to full right, & back to make these observations, the servo once more locked up, this time near the full right limit of travel. [Consider what would happen if this servo locked up in an off-center position in the air... oh, crap!!!!]
I checked the operation of my Elevator servo more th0roughly; it seems to be operating correctly without any signs of binding, so I will continue to fly with it in place.
I removed this Multiplex Tiny-S Rudder servo and replaced it with a HITEC HS-81, which is running very smoothly.
A couple of questions stay in my mind:
The red case set for the Multiplex Tiny-S servo is shaped like the black HITEC HS-81 case; are the replacement gears identical?
And more importantly, are they sourced from the same source / manufascturer? Are there other irregiular gears that slipped past the quality control inspectors, which are now out there in the supply system or installed recently in other Multiplex Tiny-S servos or HITEC HS-81 servos? [Or is this possiibly caused by a piece of debris being lodged in between the teeth on one of the servo gears inside the servo?]
[I received the following email reply from the Multiplex USA / HITEC RCD service department on 05-23-2006; the reply has a 'canned' feel to it, and did not answer my questions. In these days of easy litigation, I can understand why they might not want to say much... Unfortunately, in-flight servo lockups and the resulting potential loss of control of a flying model could lead to more than just a destroyed aircraft. Maybe I was expecting too much from them in the way an expression of possible concern... maybe not.... ]
Hi Bruce, send the unit to us and the techs will check it out for you.
Here's a repair form. http://www.hitecrcd.com/Support/service%20form.pdf
12115 Paine St.
Poway CA. 92064
Right now, we have already replaced these defective servos in these two RR version Easy Gliders, and I have no idea where the required "original receipt" might be, so I may just hang onto these defective servos for now.... I was more interested in the response I would get from the service department when they received such a report. Now you know their initial response, too.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ If anyone else has had experience with similar Tiny-S servo gear binding / lockup problems, or an aircraft (with these servos installed) being lost in a situation which might indicate a servo lockup, I'd be interested to hear from you. (I'll compile the responses and post an update.) Click here to send an email to email@example.com
Response from MikeMayberry, Hitec/Multiplex USA
Viking- Sorry to hear about the problem. We are not hearing about problems with the MPX Tiny servos to any extent, but if you do think there is a big problem like you indicate, then it would be appreciated if you send in the units you are referring to so we can check them out as we suggested. This way, if there is an issue we can document it and take any actions needed to rectify it.
The HS-81 and MPX Tiny are essentially the same servo.
Response form Jurgen Heilig
AFAIK, the Mpx Tiny-S and the Hitec HS-81 are of identical construction. While the Hitec uses all nylon gears, the Mpx servo seems to have two black and two white nylon gears. I assume they still come from the same source.
The Tiny-S has been on the market for years, and I have never read a bad report in any forum so far. If something is binding, you should see the cause by examining the servo.
P.S.: How are the servos installed in the RR versions. Could some Cyano have entered the servo housing?
BKS Reply, 05-25-2006:
Jurgen & Mark,
Thanks for the comments & concerns. If only one servo had displayed this tendancy, I would not have considered it as much of a cause for concern; however, when the second one in a different aircraft then showed the same binding / lockup tendancy, a red flag went up, so to speak.
I plan to look more closely at the gears, and see if I can identify the point that is causing the binding; the most likely possibility may be that a small piece of material / debris is lodged in between the teeth on one servo gear, which could cause this binding we have observed. I would think is far more likely than the possibility of an irregularly shaped gear making it past the quality control inspection. If this is the case, I expect that these two malfunctioning servos are exceptionally isolated incidents; I also expect that if this is the case, that the binding / lockup tendancy can be eliminated, and the servos returned to service. (Lack of further similar reports on this discussion thread would reinforce this perspective.)
I have not opened the rudder servo which I removed from my Easy Glider yet, but I now have a good idea as to what I'm looking for. When I looked inside Jim's Tiny-S elevator servo which had locked up, I found that all of the gears are now made from white nylon, the same as the HS-81 servos. If there's only one small piece of debris lodged between the teeth of one of the gears in only one place, it could definitely cause the observed binding / lockup without being easy to spot visually. I was not looking for the specific point causing the binding at that time. I'll keep this in mind when I do a further inspection. I'd certainly like to know the 'rest of the story', as I'm sure others would, too.
(I've used a lot of HS-81 servos over the years, and have never previously seen a similar problem with them. And yes, I've replaced several servo gear sets over the years, too- especially in servos used in slope combat ships!)
As far as servo mounting in the RR versions, hot melt glue is used under each mounting tab; it's a secure hold that's still easy to remove if swapping out a servo is necessary. The pocket in the foam where the servo fits is a good snug fit.
After flying my EG Electric since January of 2006 with first the stock motor & gearbox, then with a 480 brushed motor in the stock gearbox, I finally decided to install a Brushless outrunner motor.
I chose the KDA 2220L for it's potential to generate over 40 ounces of thrust on a 3S LiPo battery. The price is modest- as low as $16.50 from UnitedHobbies.com , more form sources within the U.S.A.; and reviews on their website from other users were quite favorable. (A 30 Amp ESC is also available from the same source for under $14.00, and their 11x6 folding prop with the aluminum hub & spinner is available for ~$5.00 to $6.00. Shipping is a bit slower coming from Hong Kong, but the savings are substantial.
The photos tell the story below; it was flown it it's first test flights on Sunday, 10-29-2007.
This motor is ~1 ounce lighter than the motor / gearbox combo which I removed, and my 9 cell 2/3A NiMH pack was already being positioned for balance in the very rear of the battery compartment when flying the gearboxed motors.
I filled out the nose profile with a block of 1.3# density EPP foam. (It would be easier to balance with lighter batteries with a slightly shorter foam extension, but my setup is balancing & flying fine.)
A sheet plastic cowling will be rolled to match the nose contour & clear the motor, then taped in place to do the final aerodynamic streamlining; venting for motor cooling air flow will still be allowed for on the final installation.
UPDATE: Flight tested- working fine! It now climbs well with ~15 second climbout to good thermaling altitude at a ~45 degree climb angle.
I first flew the 11.5x6 prop blades (which were pulling ~16 Amps), then switched to Aeronaut 11x7 blades (which pull about 17 Amps). I definitely prefer the 11x7 blade setup- better climb angle & speed at only one more amp of current. (The Aeronaut blades are narrower across the prop hub when folded, too, for a bit less drag.)
[TECH NOTE: I'm running the KDA2220L motor at only 77% of what it is rated & tested to handle when run continuously, so propping it up further would be very possible if an even faster climb were desired. Bbut the climb performance and speed are very satisfying now, with current well within the range that both these batteries and this motor can handle.)
MOTOR THRUST LINE ADJUSTMENT: I added two more spacer washers , about 1/32" thick ones, between the top corners of the motor mount and the firewall to adjust the motor's downthrust angle down more. It's flying closer to to how I wanted it to fly under power- some up, but not any 'zoom' under full power. I may add one more washer on each top corner location after flying it more, to test the further change in downthrust angle; but I'm looking for some smooth air to fly to do the final optimum CG and trim setup. Once that's done, I can play with the thrust line adjustment further. (Photo # 5 below shows the motor mounted without these added thin washers.)
Balance is good as set up now with the 9 cell 2/3A NiMH 'Intelect' 1400 mAH packs in the rear of the compartment. The ELITE 1500 mAH cells are said to be even stronger performers, according to Mike at : CHEAP BATTERY PACKS.COM
So I have cells on order for two new packs of those cells.
[NOTE: The entire fuselage & tailgroup had previously been painted a brilliant fluorescent orange for increased visibility at extreme altitudes - thermals can take up this aircraft and make it look really small in a hurry!! The entire under-surface of the wing is also solid fluorescent orange. Plasticote "Odds N Ends" spray paint is what I used; it bonds well to this foam, tape, etc.]
[Above] A section of EPP foam was added to the nose to extend the nose profile so folding props would fold in closely. A 1/8" thick 5-ply Birch aircraft plywood motor mount bulkhead is marked to match motor's cross-mount, drilled, and then #4 tee nuts are pressed in their holes. By orienting the crossarms in an X configuration, the thrust angle can be easily adjusted by simply adding spacer washers in the desired corners.
[Above] After tee-nut clearance recesses were cut / routed into the foam & the motor wire routing hole was done with a long Dremel cutter, 4 bamboo dowels (3/32" dia. x ~2.5" long were run through drilled holes, running from the rear face of the motor mount bulkhead back through the EPP into the Elapor foam for extra strength and rigidity. These simply butt against the back side of the motor mount bulkhead, with a generous amount of 5 minute epoxy connecting everything trogether
[Above] Firewall was sanded to final shape, and spacer washers were added over each Tee nut face to allow matching the motor's not-quite-recessed motor mount screw heads. Scotch Cross-Filament tape added last, to seal foam, reinfource, & add a base layer for the paint.
[Above] Venting for ESC and battery cooling was maintained; ready for painting.
[Above] Painted, ready for sheet plastic cowling to be formed and taped in place. This is an 11.5x6 folding prop; draws ~16 Amps (135 watts) on a 9 cell 2/3A NiMH 1400 pack. Aeronaut 11x7 blades draw 17 A, better climb speed.
Next, I made this cowl from clear plastic sheet taped into a cone, then taped it in place with Scotch cross-weave nylon filament tape. The important thing is to form and position it so that it does nor rub on the motor.