Dedicated to the Promotion of Electric Propulsion in all types of Aeromodeling

The Multiplex Heron and Solius, Part 1 of 3

Initial Costs

The Heron and Solius so good the way they come there just wasn’t any initial adventure determining how to get them to perform, nor did they need anything in the way of preparation. That is important enough to be repeated. If you read back through standard reports from the past few years by others that wouldn’t stand out as you could get a false impression since durability and damage were always omitted from reports by others and the other author’s stuff (almost) always functioned correctly on the first try. They don’t even go over slight changes, sometimes a simple and yet important as software setting the motor-controller, for getting the best out of what they had! And basics such as commenting on the servo arms not matching between servos (Multiplex sport level stuff as installed in the RR versions included) important for ailerons and coordinated flaps can’t be done without a computer transmitter to individually center servos.


What will set the durability is first that although foam takes vastly more impacts then wood or fiberglass, but once dented or chipped replacements are more practical than repairs. If you want the higher performance of built up airframes and the constant maintenance of such, get something else. Even flown as thermal ships (for violent maneuvers get something else) and landed carefully eventually the wings will develop a hinge at the end of the internal spar, watch the wing flex on the abrupt maneuvers for which these airframes are not intended, for which there isn’t much to be done other then buy new wings. Bash it in and go buy another airplane, this size can’t be crash hardened although there is some improvement to abrasion possible. Rocks will scrape the belly. Flip them and the tail will bend. You want something which can handle rougher service, get something else at a sacrifice in performance. The servos are a fine match and may be expected to outlast the airframe. That’s a strictly low performance motor in there, a best compromise with having to keep down to the competitions low initial purchase price expectations and average time between impacts. While the propulsion from Multiplex is sufficient, by the time the motors bearings give out you will have enough experience to continue. Plan for replacing the propeller blades now and then as they get beat up on landings. The motor controller is fine, even for eventual use with higher performance motors. Use them long enough and the foam at the hinges will eventually crack. Few of the members at Mission Bay will every fly a single airplane long enough to find the above out.


I can’t set to words though how little investment other than just go fly these airplanes represent and what a joy that is. While the pilots of conventional airplanes will be bragging about how much better theirs flies, you will be listening to them with your Heron or Solius in the air while they wait on the ground until they complete repairs. Learn to ride thermals or slope lift, upgrade the propulsion and how long you can stand may set the limit on flight durations.


Going off of Tower Hobbies web site (since Hobby People’s) doesn’t list them:

Heron              Radio Ready (RR) $375-

                       Kit $175-

Solius              RR $330-

                       Kit $150-

There may be sales tax in addition.


There is very little small stuff to add. As in for the RR versions you will likely have to change connectors to the battery. If you use the battery to climb out and enjoy flinging these RC airplanes around in still air, with their six minutes motor run time, flights are around twelve minutes. Even if you don’t hunt thermals or slope lift, if you climb out and glide around it’s more like forty minutes for the Heron and thirty five minutes for the not quite as efficient as Solius.


To restrict the economic analysis to a typical SEFSD member, we are going to exclude the bits and pieces such as AMA and Club Membership, the Transmitter, receiver and Battery charger along with the simple tools required now and then. That bit with the transmitter and receiver needs careful evaluation. For use with the Heron even the current Dx9 (two antennas built into the case) has only three coupled positions for the wing control surfaces, and it could use four.  My old style Spektrum Dx6 (single antenna) won’t administer a Heron well as it can’t really take advantage of setting the ailerons as three positions are needed and it is only equipped with a switch for two. These long efficient wings get even more efficient near the ground, my simpler HiTek transmitter has five channels with no coupling, so the ailerons can’t be switched to up, used to force it down for landings, so the landing approach could easily continue beyond the whole length of the Mission Bay runway! See the following, you need to know how to fly a thermal ship, these aren’t beginner airplanes. The latest Dx6, the one with the two antennas integrated into the housing which should be considered an unrelated transmitter, does better.


Although I recommend three batteries for a flying session, two inexpensive 3S 2200 mAh LiPos would cost around forty five dollars net. At least once in the service life of these the propeller blades are going to require replacement at twenty dollars. I recommend making that purchase at the same time as the airplane. For the Heron that puts it at about $420- to which at fifty flights works out to around nine dollars a flight. Manage your landings/crashes better for a hundred flights and it’s four and a half bucks a flight.


We don’t yet have enough flights on ours to complete the economic evaluation. In any case a single impact can change everything. Further, if you price out the components you can’t buy them separate and glue it together yourself for the price of the RR versions. And even me, who constantly fiddles with propulsion was satisfied with them equipment wise they way they came. See Part 2 for not leaving well enough alone.


They aren’t All Alike

In this motor-thermal class there are a currently a plethora of different kinds of all look a lot alike (hundreds) plus thousands of gliders from the past, all of which also look a lot alike. What’s new here is these decent performing ones which are carefree. As in for an a RC airplane which can actually thermal and slope soar, in terms of net cost per flight over fifty to a couple of hundred flights with almost no investment in assembly or maintenance, these are the best. Cheaper neither flies as well nor hold up as well, nearly all comparable size and configuration RC airplanes at this price level in foam (even the Multiplex Easy Glider Pro) are restricted to nearly still air. More expensive though does fly better although at a cost of being fragile and requiring more skill from the pilot.


Assemble a Radio Ready Heron or Solius in minutes out of the box it came in at the airfield (the ohs and ahs of a new airplane take longer than putting it into use), install your receiver and program your transmitter, put the battery in and go fly. That could go on for months of flying it twelve minutes (motor run time six minutes in the from the manufacturer configuration) to three hours (you needed to sit down as there were still thermals or slope lift) at a battery charge once a week. There is no maintenance as such to keep a Heron or Solius flying, no constant mending of the covering or tearing it open to repair breakage. Eventually the leading edge of the foam wing starts to take abrasion or you bend it on a landing. Beyond that from previous experience the bearings in the motor will start giving out somewhere beyond fifty flights. Replacement motors are easily available as are either a better motor (recommended) or bearings. As configured by the manufacturer and the requirements of the airframe most fiddling with the propulsion is with a goal of improved duration and efficiency, these ones don’t need any more power. If you land on the sandpaper of Mission Bay you need to allow for replacing the plastic folding propeller blades getting scraped on the hard sandpaper like runway, the occasional rocks from the molehills in Rhein-Main are analogous. The original blades are just fine, better ones didn’t bring much improvement. Other than that (in Rhein-Main we have to wipe the mud and snow off now and then) just go fly. We don’t even need to close up the open cells between the foam as with the Easy Glider and Twin Star (II) as with this higher density foam the crud doesn’t get between the cells near as bad nor do they dent up as easily.


You can get far better performers

than the Heron and Solius. Those F5B seven horse-power rockets (Heron and Solius about one fifth of a hp) as seen down at Mission Bay look just about the same sitting there although they involve an investment of two thousand and five hundred dollars, double that for the elaborate transmitter required. No Heron or Solius is ever going to go that fast.


And truth is one size smaller, as in five or six foot wingspan with around four hundred square inches of wing verses these seven foot six hundred and fifty inches for “use the motor to get to thermal hunting altitude” is better suited for Mission Bay, see the Electro Glide contests for recommendations. Part of the issue is Mission Bay is flat and often breezy, about walking speed to two or three times that fast wind. So we can’t fly all that far away from where we stand nor fly all that high up. So more than a few minutes with a motor-sail plane except to tour around they aren’t all that sporting. For Rhein-Main the Heron and Solius are a blast.


In case you were wondering, for the once popular Harbor Soaring Society, home field Estancia in Costa Mesa two hours away from Mission Bay, these would be decent airplanes. Except that most of the members, the thermal fanatics, have all but ceased flying there, the slope soaring is gone with the lift due to turbulence from the trees below.


But the Heron and Solius in Radio Ready only cost about four hundred dollars for a fully fitted out airframe including assembly, motor, propeller, motor controller, servos and servo extensions. For the Heron you need either a seven/six channel computer transmitter, for the Solius a four channel standard radio (Solius) is sufficient although a computer transmitter to change the wing profile in flight is a benefit. For which you fly carefree. The factory built up balsa, carbon fiber spars and iron on covering motor-thermal RC airplanes are at about the same price better performers, until you scrape a wing tip, hit a twig or just leave it in the sun to warp and then have to repair them. We wound up changing motors, our choice was for more effective more expensive ones (run times went up by a third with the same batteries) but only due to the original wearing out as more power wasn’t much of an advantage.  


Watching the latest in ruder, elevator and spoiler gliders on a day with no measurable wind, thermals or slope lift, flown off a tow starting at about a hundred and fifty feet up that modern high performance glider airframe stayed up for four minutes at that hilly flying field in the vineyards high above the Rhine River. Whereas my old mid nineties Wanderer (painstakingly assembled from individual sticks of balsa, spruce, glue(s) and iron on covering, there were no ARFs then) would have been on the ground in half a minute. A Heron would stay up a little longer then a Solius at a minute and a half if you used the motor to get to that starting altitude. Back when a Wanderer was what you started flying with even the world class thermal ships being flown by world champion pilots off a three hundred feet winch launch were back on the ground in one minute unless they found some lift. I know because I flew with the world champions of then with the Harbor Soaring Society, some of them could stay up for hours. The Heron and Solius are no match for modern high performance pure gliders. But they beat my Elektra from back in 1995 which had thrust for one minute total, climb on that was two hundred feet, for which without finding either a thermal or slope lift the total flight was about two minutes plus constant repairs required.  


Variations on a Theme

There isn’t that much price difference in the airplane portion between the Heron and Solius. After that comes it down to your transmitter and expectations. If you have a seven channel computer radio (six with slight losses if it can’t mix the flaps into the ailerons, that being able to tune the airfoil by deploying the wing control surfaces a little down or a little up from neutral at the flick of a switch makes a improvement too) for somebody who can program it the Heron is the better flyer. A Solius will fly fine with even the simplest of four channel radios although with that shorter wing and higher wing loading it sometimes has an edge on the slope if it’s breezy. If you have the pilot skills and a suitable radio the Solius benefits from adjusting the wing in flight too.


In contrast to previous reports there just isn’t any need to improve the latest from Multiplex at all nor is there much you could change even if you were so inclined. That is quite a break from my previous reports. Then too these are bigger airplanes then my previous reports covered, with the bigger flies better but crashes harder aspects. Let’s take a better look at that as it is really important. Many intermediate sport pilots have neither the skill to set up an airplane correctly nor to interpret tiny changes in trim. Increase the size of the airplane and those differences are easier to see, slight bouncing around in flight evens out, important for closer to the end of life’s journey pilots things happen slower and bigger is more easily seen. A vast majority of pilots down at Mission Bay not in it to win an all up last down contest would enjoy these two airplanes at a very nominal cost per flight. But where as a Panda would bounce off of a stick with a dent in the wing you might have to write off a Heron or Solius.


Both the Heron and Solius are, as thermal RC airplanes with their seven foot wingspans, medium sized for their main application of thermals and depending on your slope either kind of big (Point Loma a no, but then only a fool would fly there anyway, too many rocks hidden in the grass out around Jamul) or medium sized (Torry Pines). Although short on places to slope soar in Rhein-Main, for us on the west side of the metropolis it’s likely to be Mensfelderkopf and some places in Austrian and Italy’s Alps. In both cases satisfaction, provided you have a large and smooth landing place.


Neither a Heron or Solius is a Still Air Trainer

Although both the Heron and Solius would be pleasant to fly at Mission Bay, they may be one size above optimum there where we really must observe the height restrictions although that being bigger makes them more stable fliers, easier to see and easier to perform the fine adjustments to the control surfaces. Then too an advantage of these is getting way out there riding a thermal up then being able to put the nose down and adjust the wing profile for some moderate speed so you can get to the next thermal before landing; We just don’t have enough room to really use that at Mission Bay. Worse, in a single circle they all but twice disappear when head or tail on. That’s a consequence of any thin and therefore thermal effective airframe. They would be decent performers at Torry Pines and anywhere you have the room upwards, outwards and a decent place to land.


Although you could learn to fly with anything, even though more than three times walking speed renders something like an Easy Glider about useless, I’d recommend an up-motored Easy Star (II), Twin Star (II) Brushless or even a Panda would be a better choice for the first airplane. Although easy to fly, the Heron and Solius aren’t all out thermal machines, but from behind or straight on even experienced pilots can’t see them so thin are they and they break on bad landings.


The most likely bad landing(s) at Mission Bay are caused by pilot error. Approaching the ground at barely above stall speed in the hope it gently sets down, either the famous transition from laminar flow to turbulent half way down the runway flips your airplane up into a stall, or you drag a wingtip and as it pirouettes around the opposite wing comes up to flying speed flipping the airplane over no matter what you do with the control sticks. Hang around and watch our racing pilots, they come in well above stall speed and push the nose in to drag the excess speed off quickly on contact thus ending the flight without damage. It is mentioned here again as with their more efficient wings the Heron and Solius are even more prone to that then less efficient airplanes.  


For a trainer,

at Mission Bay and Rhein-Main, since you may restrict your first lessons to nearly still air, you want the airframe to limit the speed to variations on slow only. Put the nose down on the Heron (adjust the wing aileron and flaps even) and Solius (adjustments not quite as good due to the ailerons only wing) they accelerate to medium speed. In a circle they twice (almost) disappear. For a trainer we want limited handling, indifferent tuning adjustments and self recovery. You have to get the balance right on the Heron and Solius (buy the radio ready version, use the recommended battery and you will find that out in that the variation on perfection is the variation on the weight of different batteries as in (185) to (205) grams for typical 3S 2200 mAh LiPos), throw the sticks over on these and they aren’t aerobatic specialists, but they will do (slow) antics. These are more critical airfoils then seemingly similar trainers, screw up and get the control surfaces wrong and they will not fly as right as they should. Get crossed up in flight and just letting the control sticks of the receiver center will not get them back to level flight before hitting the ground. Then too the blunt leading edge of trainers, part of which makes them “ding” resistant and allows for learning how to handle such easily torn things which all flight stuff is, is part of what makes them regarding speed, variations on slow. The Heron and Solius don’t have fragile wings, but hit something and the leading edge will dent and chip, step on one and buy a replacement. Point them straight down from the Mission Bay height restrictions, pull the elevator all the way back and watch the wings bend, too far. I have foam flying wings with car tire tracks on them that still fly… And, part of the aerodynamic price of the efficiency of these long thing wings is you must use the rudder for turns.


As such the Heron and Solius could be considered ideal slope trainers for slopes where the wind is inconsistent on mild to moderate wind speed days since if you make an hour drive to find the wind at an angle to the slope or has quit (so a pure glider is useless) you can still have a good time using the motor to get them going. We used to show up at the slope with three gliders, each a little different for conditions. And back in the balsa era we were doing good if one of them was still flyable without repairs at the end of the session.


At Mensfelderkopf (outside edge of Rhein-Main half an hour away) the slope lift is indifferent, the landing one of those mythical big grassy fields, for which should the wind quit you can send an airplane this size well out there looking for a thermal and bring it back on the motor if needed. That may be a major advantage of the Heron and Solius, these are durable thermal/slope machines for which the resident club, who mostly fly pure gliders (often scale) will not take to the air on days with wind. And since they look semi-scale they would be tolerated.


As noted in my report on the Easy Star (II) Jamul can be a great place to fly, but these two are just too big to land out there. The issue is rocks hidden in the grass. Unless you can accept ruining airframes more often. This is a new era readers, buy it complete, fly it until damaged and buy another. There will be a scrounger around (such as the author) willing to buy the remains as the servos and motor controller have an expected service life longer then the mean time between writing off the airframe.


Simulations and Such

Simulators, as in on a computer at home, are now a part of RC flying. If you have a specific type you want to try out, in particular even for moderately skilled rc pilots learning new and difficult aerobatics goes well on the simulators, for which you really want a simulation as close as you can get to your specific airplane. But when it comes to these long thing wing thermalers, even though there is no exact match for the Heron or Solius, neither is there any need as any thermal type would serve the purpose of getting familiar with this type of RC fixed wing flight. If you can set up the ailerons and flaps to move together and for both wings try slope soaring with the wing control surfaces deployed up for speed. On my simulator the bound to the program controller is like a non-computer transmitter, it can’t link surfaces.


Something else which doesn’t show on the simulators, in the computer world the angle of the motor to the fuselage is always correct, the airplanes are never torn, bent or a little damaged, the servos matched and so the control throws always perfect. A vast majority of our real world RC airplanes the motor’s thrust is not aligned with the momentary center of drag. As such no amount of fiddling with the down thrust and side thrust of, let’s say a Fun Cub, is ever perfectly correct through the whole speed range. Change motors and propellers and the required down and side thrust change. Almost all of my airplanes (the many excellent F3A competition aerobatics airframes excepted) the best trim I can get is that on application of full power that for about the first thirty feet of forward flight the airplane pulls down two foot and from then on climbs, none in our simulators do that.


Or landings in Rhein-Main are rough (what looks like landing gear is actually a catch the grass arrestor to flip over) and yet we have been getting a couple of hundred flights out of our slightly reinforced foam airframes. A recent acquisition in the form of a “model” Sukohi for use as a F3A precision aerobatic trainer in the just over three foot wingspan size, after treating it’s nose with fiberglass resin, was doing ok. But the landing speeds were a little higher than the previous airframes, on a landing it bent. All you noticed was a new (2) mm (3/16) inch gap at the canopy. It was enough to change the angle between the wing and horizontal stabilizer, or angle of incidence (zu Deutsch Einstellwinkeldifference) enough to simulate being suddenly tail heavy and throw the handling off. There was no reasonable repair. This is the new era, when it breaks or bends get another one. If you don’t have the skill to recognize that kind of thing, you need tools to check for it, get yourself some help.


Which brings up an initially disconcerting aspect of the Heron and Solius. Even with the Original Equipment from the Manufacturer (oem) propulsion the climb is automatically correctly on application of full amps, they pull up at the most efficient angle for gain in altitude. The simulators don’t do that. With his many hours of enjoyment of precision aerobatics (where in thrust is axial to center of drag so they have minimal pitch changes as the thrust changes) I had difficulty convincing the friend with his new radio ready Heron that the manufacturer had made it right, for the should be correct for even only slightly experienced, pilots. You can mix in some down elevator to the amp stick with the computer radios ya know.


We use Real Flight 5,5, which always has the balance correct, something missing in the real world. I don’t believe the actual hunt for thermals functions on simulators anyway, about all a simulator can do is get you use to these long thin airframes. The most important part of flying, landings, nobody can perfect on home level computer simulations. If you can’t reliably land an Easy Glider or Easy Star (II) or Twin Star (II), stick with them until you can before moving up to a Heron or Solius. As for slope soaring (nor really possible with the Easy Glider or Easy Star) the computer generated stuff is actually pretty good. It didn’t take me long to be bored with flight simulators, what held my interest the longest was virtual slope soaring. For which I recommend set the wind speed to moderate and practice with a thermal machine if you feel the need.


Something unexpected, the little girl niece enjoyed creating her own world in Real Flight decorating to her content a place to fly. Crashing, on the computer at least, brought giggles. Disappointingly, before we had a trainer setup and the time she transitioned into horses and others her own age took precedence as we had expected of her early teens.    


As for Videos; They in some ways suffer from the same lack of binocular vision as simulators. For all the videos I watched of these two when we actually went to flying them they seemed slower. It may be a case of which reality came first? In case you were wondering, the final impulse to spend some money was a friend sending me a video of slope soaring near Lake Garder in Italy and thoughts of bored windy days when I just had to get out of the apartment.


The Before Fifty Flights Pre-Evaluation  

Although this article is specifically addressed to the SEFSD and my personal friends, I can neither fly with you personally and fit this in with your understanding, nor can words and pictures adequately describe flying a Heron or Solius. And if you fly in constant wind or at higher elevations that needs to be taken into account.


Be that as it may I can make the recommendation that are you sufficiently experienced to handle a thermal ship, or at least get sufficient help at the set-up and use of such, and have a type reasonable landing place, that the Multiplex Heron and Multiplex Solius are great airplanes, if minimum cost per flight and the carefree aspects of modern high performance foam/composite construction for learning thermals and slope soaring appeal to you.


Motors, Propellers and Batteries

Because We don’t fly Simulators

And there is More to be Had


In case your reading, and simulators, where everything is always wonderful, created a (mistaken) idea that everything is therefore equal and identical (when is the last time a report even mentioned motor efficiency?, or crash resistance?) in a preview of Part 2 included are some recent (preparatory) experiences with motors that could be used in a Heron or Solius.


Everywhere I/we fly our slightly upgraded ARF foam airplanes get the same comments and questions.


It looks beat up.                                                because we fly a lot Our reinforced stuff with folding propellers can take a hit and keep going.

I didn’t know they could fly that well.                  We paid the money for and use better propulsion, tuned correctly and get everything set up straight

How do you get it to stay up there so long?          both of the above About twice as long as reported by others. sometimes irritatingly so

To be continued…