Sonic Liner by Multiplex - RC Groups
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Sonic Liner by Multiplex

Multiplex describes the Sonic Liner as: "The model of the Future." They have made a plane today based on concepts discussed and drawn by aircraft manufacturers of designs that might be seen in airliners in thirty or fifty years and they have captured that beautifully. The Sonic Liner is made of resilient Elapor and with its Delta wing and forward positioned stabilizer/elevator: "These ideas are now reality - today you can fly into the future."

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Wingspan:1265mm, 47.3 ounces
Wing area:42dm2, 650 square inches (per Multiplex)
Weight:57 ounces
Wing Loading:37 g/dm2, 12.67 oz sq ft
Length:1300mm, 51.2 inches
Motor:Twin speed 400s
ESC:Pegasus 35P by Castle Creations
Battery:8-cell Zapped 1950 pack from Diversity Model Aircraft
Radio:JR 8310 Transmitter, Hitec 555 receiver (for JR) and 2 Hitec 81 servos & 1 Hitec 85
Available From:Multiplex


Multiplex describes the Sonic Liner as: "The model of the Future." They have made a plane today based on concepts discussed and drawn by aircraft manufacturers of designs that might be seen in airliners in thirty or fifty years and they have captured that beautifully. The Sonic Liner is made of resilient Elapor and with its Delta wing and forward positioned stabilizer/elevator: "These ideas are now reality - today you can fly into the future." Best of all it just took a couple nights effort to assemble this plane of the future using a gluing method that was extremely fast.

When I opened the box and saw the size and shape of the plane I thought of a Twin Jet on steroids. The Sonic Liner while definitely its own plane has much in common with its smaller predecessor. It comes with twin speed 400 motors that mount in the back of the wing and push the plane through the air. It has a massive body section to which the nose of the plane is attached in the building process and it has twin tails with no moving parts. However the Sonic Liner is much larger then the Twin Jet, it comes with a functioning Canard for its elevator and it looks very futuristic. Thus it has a forward elevator and rear ailerons not elevons for control as in the Twin Jet. With it's massive length and weight of over 3 1/2 pounds it should fly a good deal slower then the Twin Jet but I think it should be a good flyer. It starts flying with a hand launch. Fortunately, I am pretty good at hand launching. But I am getting a little ahead of myself so let's assemble the plane and then worry about launching it.

It sometimes pays to read the instructions! By doing so I learned that the recommended way of building this plane is using cyno-acrylate activator, also known as, kicker, on one part and letting it dry and then applying regular medium cyano-acrylate (CA), not foam safe CA, on the other part and putting them together to let the glue join the parts. You have to work quickly arranging the parts using medium CA as the glue hardens in seconds. Trial fitting the parts first is highly recommended in this type of quick assembly. They recommend against using epoxy (Except for installing the Gunther props.) as epoxy creates a brittle joint that is not really very strong with these parts. I built with medium CA and kicker per the instructions and it made for a quick and strong assembly.

The instructions come in several languages and there are illustrations of each step in the center of the booklet. I simply photocopy the few pages of English instructions so I can look at the pictures when I read without having to flip back and forth. You could simply take the instruction booklet apart to read the English without flipping back and forth to see the pictures. I photocopy the English instructions because I like to keep the booklet intact for possible future reference down the road. The instructions are short and to the point and the illustrations helpful. This plane is not intended for a beginner's first plane and I found the instructions completely adequate for the level of experience for which the plane is intended.

Kit Contents

When you open the kit box you see a lot of foam parts and a small orange box taped to the side of the kit box. That orange box holds two Gunther props, two speed 400 motors (six capacitors) and a wiring harness. Under the foam I found a bag of parts including the control horns and control wires to connect them to the servos. Special snap connectors for holding on the top of the fuselage/canopy, various bolts, nuts, Velcro pieces and two rods to connect the wing panels to the main fuselage that allow the wing panels to be removable for transportation. There was the previously mentioned instruction booklet and even an updated instruction correction page. There is a nice page of decals with stripes, windows and doors to finish the plane. Most of the box is taken up with the plane parts made out of Elapor a material stiffer but in some ways similar in feel to EPP foam that is resistant to breakage. The parts include the large foam fuselage piece, top piece for the central fuselage and top and bottom nosepieces. In addition to those there are two tail fins, two wing panels, the canard (forward located full flying stab), four pieces for the wing joiner areas and two pieces of motor cowling that hold the tail fins.

Assembly of the Sonic Liner

After confirming that the kit included all the parts listed in the instruction booklet and the supplemental instruction sheet you are ready to assemble the kit. The plane comes with molded grooves in the bottom of the wing to secure the wires for the motors and the servos that go out from the fuselage. The first act of assembly is making tunnels from these grooves to the inside of the fuselage and motor nacelles. I used a 1/4-inch drill bit and an Exacto knife to cut the necessary four tunnels into the fuselage and four tunnels into the two motor/servo nacelles. I started at the fuselage and I simply hand turned the drill bit between my fingers to make the initial holes from the wire slots into the fuselage. That was all that was necessary for the motor wires. However, since I was using servo extension wires with attached plugs, the holes for the servo extension wires into the fuselage needed to be bigger. I used the Exacto knife to slightly expand the holes to fit the plugs. To make the tunnels into the motor nacelles I simple used the Exacto knife.

The next step is gluing the two sections of the nose, top and bottom, together. Per the instructions I sprayed one piece (the top piece) with CA kicker and let it dry. When it was dry I trial fitted the parts and when certain about the fit I took them apart and applied medium thick CA to the parts of the bottom piece that would come in contact with the top piece and put the two parts together tightly and held them together for a half minute. I was happy about how nicely the parts went together. The next step is gluing the now completed nose to the main fuselage section. These parts have some angle cuts to match up and give some good contact surface. I recommend that you do this joining of the the nose to the main fuselage section over a full-length flat surface. Put some wax paper under the area of joiner for the nose and the main fuselage to protect your work surface. Spray the main fuselage parts that will match up with the nosepiece with kicker and let it dry. When the kicker is dry, trial fit the nose to the fuselage tightly while keeping the nose and the fuselage flat on your building board. When you are happy with the fit, separate the parts and apply the medium CA to the part of the nose section that touch the main fuselage and push the two together firmly and hold them together firmly and flat against the work surface for about 1 minute to assure a good firm connection on the parts.

The very long canopy is held in place with three pairs of locking lugs or snaps. The main snaps are glued into molded slots on the inside of the fuselage with the Ca and kicker method described above. Be sure to get these plastic locks all the way down into the molded slots. Later in the building process the canopy is installed by inserting the six latch lugs a pair at a time into slots on the bottom side of the canopy. Before gluing you want to make sure that the canopy is properly located on the fuselage as far as front and back are concerned. When you have this position properly determined you apply CA to the pair of latch lugs in the front but don't use any kicker. Partial insert them in the proper location in the slot and then push the canopy into place and hold it for a minute. This pushes the latch lug into the foam to the proper depth to hold the canopy at the correct height. When you are certain it is glued in the right spot, remove the canopy and spray kicker on the foam at the base of the latchkey to fully set the glue. Repeat for the middle pair of latches and then the back latches. I was pleasantly surprised about how well the process worked.

The instructions explain the general assembly well and there is no need to review every step here but I will touch on a few more points. The kit supplies a motor harness for connecting up the two motors. This requires soldering the end of the wire to the back of the speed 400 motor and at the same time adding three capacitors to the back of the motor as well. Of course you must first snake the motor wire harness from the fuselage out to the motor nacelles. Since you want the motors to work as pushers you must reverse the wiring so solder the positive wire to the negative connector and vice-versa. After the soldering is done the motors are glued into place. Spray the foam nacelles with kicker and let it dry. Then carefully place medium thick CA on the motor casing to line up with the raised foam spots in the engine nacelle and being sure you don't get any glue inside the motor place the motor so the portions of the motor with glue are on the raised foam and hold for 30 seconds. Simply repeat for the other side.

The wing joiners are very simple to install. I sprayed kicker on the fuselage and wing panels where the top half of the wing joiner boxes are and let them dry. Once dry I installed the two bottom half pieces of foam for the wing joiner boxes one at a time by placing the medium CA on the sides and bottom outside edges (But none where the wing joiner tube would slide in) and quickly pushed them down into place. When the glue dried I trial fitted the joiner tubes into these boxes and the fit was nice and snug. On the wing panels I first glued the wing joiner tubes into the slot for them and then glued the bottom half of the wing joiner boxes over the tubes. Per the additional instruction sheet I glued a small plastic plate onto the fuselage that helps serve as a guide/support in lining up the wing. When all the glue was dry I trial fitted the wing panels and they fit nice and snug against the main fuselage nice and secure but still removable for transportation and storage.

Pushrod Connectors
I decided to give the push rod connectors their own section because they are so well done. With the aileron servo in the main fuselage section and the control horn in the aileron on the removable wing panel they came up with a way to keep the plane in perfect trim while allowing the parts to separate. The picture shows in a second something hard to describe but that works perfect. On the wing panel is the control horn and screwed into the control horn is a plastic articulated connector housing. When the wing is joined to the fuselage an articulated metal swivel block snaps into that housing and connects the aileron to the servo through a pushrod. When you want to separate the wing from the fuselage for transportation you just snap the articulated metal swivel block out of the housing and it remains connected to the main fuselage through the pushrod. Thus the linkage just snaps together or apart with the proper adjustment for flight control never being altered. This is a very good working design.

Additional Parts and Tools Needed
The kit is complete except for radio gear and that requires 3 servos, a receiver, a speed controller and a number of extension wires to connect up everything. I am using a Hitec 555 receiver and since there are two aileron servos I will be using a Y connector harness. The receiver is mounted near the front of the fuselage behind the forward elevator. I found I needed a six-inch servo extension wire to connect my elevator servo to the receiver. I needed two, two-foot servo extension wires with the Y harness to connect the aileron servos to the receiver and I need a one-foot extension wire to connect the speed controller to the receiver.

I am using 2 Hitec 81 servos for the ailerons. To fit them into the molded servo holder in the engine nacelle I had to cut out two foam bumps to make room for the base of the servo. I am using 1 Hitec 85 servo for the elevator. To properly fit it into the mold in the elevator/canard section I had to cut the two bumps to make room at the bottom of the molded space and slice about 1/32" of an inch out of the matching molded space in the fuselage. I am using the more powerful Hitec 85 because of the size of the plane and knowing the elevator takes more strain in flight then do the ailerons. (There is a warning in the instructions and supplemental instructions not to abuse the plane in flight and specifically warns against speed dives from high altitude.) I am using a Pegasus 35P controller from Castle Creations to power the motors and the receiver. This controller is programmable and will allow me to fly the plane with both Nimh batteries and later possibly with Lithium Polymer batteries. Although the instructions recommend a 7 or 8 cell 3,000 Nimh battery pack to power the plane I will be using a new zapped 8-cell pack of 1950 mamp batteries to power this plane for the test flights. This battery pack is from Diversity Model Aircraft and should work great with this plane and lets me get the pack broken in for use in a brushless powered electric glider I will be flying later in the month. This battery pack will easily supply more amps then these motors can use. I am trading off the added duration of the larger 3000 pack for a weight saving of about five ounces.

Glues used where the much mentioned medium CA with kicker for everything but the propellers. The props were attached with five-minute epoxy per the instructions. I used a soldering Iron and solder to connect the motors and speed controller. I used an Exacto knife to cut the ailerons loose on the ends and for making the tunnels for the wires along with a 1/4" drill bit. Finally I used a couple of screwdrivers for the control horns and the mounting bolts. An Allen key is included with the kit for use with the Allen nuts on the control horns. Finally I used scissors to cut out the decals.


Consideration was given to make this plane easy to dissemble for storage and transportation. As mention above the wing tips come off quite easily for transportation. The canard removes by unscrewing one bolt and unplugging the servo. The twin tail fins are glued in the top half of the motor nacelles but the top half of the nacelles are easily remove by unscrewing one bolt and sliding off a rubber O-ring. The fuselage remains long at over 51 inches but the components can easily fit in a car's trunk or the back seat of most cars when dissembled. It will store under a bed dissembled.


Flight is started with an overhead hand launch. Because of the size and weight of the plane I made the first launch with a running start with a good hard level forward throw. With my left thumb on the throttle stick I started running forward. I slid the throttle up to full as I threw the plane forward as hard as I could in a nice level toss. I raced to get my right hand onto the transmitter to make any necessary adjustments to avoid crashing the plane. By the time I got my hand on the control stick the plane was thirty feet in front of me flying level and starting a slight right bank turn. About four clicks to the left with the aileron trim tab was all that was necessary to obtain level flight. To my surprise the plane lost no altitude from my hand launch. (I did mention I was pretty good at hand launching.) Nor had it climbed in over 150 feet of flight. The elevator as set in its molded position was dead solid perfect for level flight. I pulled some up stick and the Sonic Liner began to climb. I also intentionally applied some right aileron and it banked right as it climbed. I made one circle of about 200 feet diameter and I had climbed safely above the local park trees. I continued climbing to about 400 feet and then leveled off. I next reduced throttle to about 50% and the plane slowed down but continued to fly level. After a couple slow circuits around the park I killed the motors to see how the plane glided. Here was another surprise in how well the plane glides. On this first flight it was before 9:00 in the morning and in calm conditions so it was dead air. The glide ratio appeared to be about half that of my Hummel/Miss 2 but about double that of a GWS fighter plane.

Motors were turned back onto full and with the Diversity Model Aircraft 1950 8-cell pack I was able to climb at about a 30-40 degree angle. When back to altitude I entered a slight dive at full throttle and entered into a loop. I tried for a little to large a loop and almost lost my forward/upward momentum but I did complete the turn at the top and my first loop was closer to a cursive L then an O. After regaining speed I made a nice smooth loop at full throttle. The remainder of the first flight involved making smooth turns and low level passes but no high speed dives. The plane handled perfectly and always went where it was told. It looks great coming at you or going away from you especially at low level. I had no bad handling experiences and no stalls during the first flight. After about ten minutes I set up for a landing and simply glided it in and slide to a stop in the grass with a slight flair just before touchdown.

Watch a video of the Sonic Liner in flight!

My good friend Jeff Hunter piloted flights two and three. This allowed me to video tape the flights and take some in air shots. The still pictures really don't do the Sonic Liner justice. The video really gives a much better idea about the planes handling and majestic appearance in flight. Jeff performed the first axial rolls in the test flights and started the first couple while in a slight climb. They went so smoothly that later he did three in a row in level flight but unfortunately at that point I was only watching and not taping. Despite its size and weight and only being powered by two speed 400 motors the Sonic Liner remained basically level in doing those three axial rows. While admittedly not very scale flying for a futuristic passenger liner they are a lot of fun and easy to do. Jeff's first flight was also with the Diversity Model Airplanes 1950 Mamp 8-cell zapped pack. His second flight was with an 8-cell pack of heavier Nicad cells. Jeff and I both noticed a difference in performance between the two packs. The climb and speed with the 1950 pack was slightly better then the heavier Nicad pack.

I flew the third and fourth flights by myself and found I could safely launch with just a firm toss and one step forward. By the fourth flight I had moved the C/G almost an inch behind the recommended balance point of the bumps on the bottom of the fuselage. This increased the low end of the speed range and slightly improved the planes responsiveness. I have attempted to stall the plane several times at a safe altitude everytime it just drops its nose a little until it picks up speed again. That is a nice feature I have found in other canards I have flown in the past. In normal flying I found no bad tendencies. Its speed range is good but top speed is much less then that of my Twin Jet. Still it flies with authority as you can see in the attached video. While the Sonic Liner does nice smooth axial rolls and small loops it is too flexable (built stock) to be an all out high-speed acrobatic plane. The additional instruction sheet even warns against high-speed dives. I have enjoyed the flying I have done with the Sonic Liner thus far and look forward to many more flights with it. I will probably add some dark blue stripes to the underside to help increase visibility at altitude. Seagulls have had a strong reaction to the plane that has appeared both favorable and negative at times. Twice they have gone out of their way to fly over by the plane and on one occassion, when Jeff was flying, they scattered almost violently when the plane simply turned back towards them. The second time I simply turned in front of them and they remained interested for about a minute and then resumed flying their original course. I have never seen this type of interest by the seagulls in my other planes.


I found I really enjoyed the recommended construction method. I had no trouble working the parts together correctly despite the quick set-up time of the medium thick Ca. I hope no one tries to glue it with thin Ca and its almost instant set-up time. The molded tunnels in the wing and fuselage for wires are a very nice feature. The disconnecting linkage (That retains proper linkage position.) for the ailerons allows for painless and quick assembly and disassembly. This will ease both storage and transportation for owners of the plane and that ease of transportation and assembly will translate to more use at the flying field as well.

I especially like the size and appearance of the plane and I think you get a lot of bang for your buck with this plane as it comes with the two speed 400 motors. If you like scale type flying and flying a R/C passenger plane as a real passenger plane flies, this will probably float your boat. I was perfectly happy with the performance using the speed 400s. If you live in a windy area you may want to upgrade to speed 480s and 10-cell packs. I know a number of you will go brushless because of the Tim Allen (MORE POWER!) that rests inside of us. I won't be upgrading mine as I am happy with the standard performance. For those that do upgrade I recommend that you use your power for vertical climb and stay away from high-speed dives.

If you like the looks of the Sonic Liner and are an intermediate flyer or better then I recommend the plane for the ease of assembly and it's good flight characteristics. If you like to fly high you might want to add some color to the underside of the fuselage and wings for increased visibility. This is not a hard plane to launch but it does require a good firm throw. It's big enough that if you fly with a friend you may feel more comfortable with your friend tossing it while your hands are on the transmitter controls.

Footnote: If you noticed the propellers spinning in the video when I said the plane was gliding that is because the Gunther props were just free spinning in the breeze.

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Dec 01, 2003, 11:04 AM
Official Boat Bum
Eddie P's Avatar
Mike - Great review. Just when my "all CF and glass mouded" models outnumber the foamies I am tempted again by this sort of review!
Dec 01, 2003, 12:26 PM
Registered User
Guess what Ed, I have one on order. Just when I was heavy into Heli and I saw this Sonic Liner, and I knew I got to have one. I don't know about two speed 400 only because they don't last long. Maybe two speed 480 (diamond blackhawk 480). I am considering 2 mega 4T spinning 5X5. The 1950FAUP Zapped is the choice, cause I have them. When this thing show up on my door, I would like to get together with you to stiffen it up for brushless. You know me, I like box turns and going vertical.

Dec 01, 2003, 11:23 PM
Interesting model; good review. Sure to turn heads at the field!

One nitpick (I proofread for fun): wingspan is probably in inches, not 'ounces.'

Dec 02, 2003, 04:39 AM
Registered User
I've been flying the Sonic Liner for about 4 months now on 7 cell 2400scr packs and have been most impressed even on the supplied 400's. Last week-end I let the 'expert' in our club who now only flys turbine powered jets have a go and he was very impressed with how smooth it flys and then proceeded to perform rolling circles with it. The only change I've made is to provide proper cooling to the ESC as it does overheat on hot days inside what is a sealed foam container and Ive put in two reverse timed 400 in which improve take off slightly although the Sonic Liner does take a little time to reach full flying speed but remains totally controllable and stable at all times. A good trick is to perform a low slow fly-by and pull the nose up to 45 degress and apply power and watch the stunned faces as the Sonic Liner flys past nose high and slowly climbs.
Dec 02, 2003, 08:56 AM
Registered User
Michael Heer's Avatar
Terry you are correct. I proofread my article multiple times and didn't catch the ounces instead of inches. It is of course inches for the wingspan. I would correct it if I had access to my article but I don't once it is posted. Mike
Dec 02, 2003, 10:25 AM
Registered User
I have discussed it with Eddie P about putting 2 Mega 4T with APC 5X5 prop and landing/retract gear on the SL. I will get my SL somtime next week, but mean while getting all the electronics ready. I have 3 HS81 to be use, and 555 RX. Will be using 8 cells of ZAPPED FAUP1950. My concern is the airframe. Can someone tell me the potential weak spot to reinforce (fiber glass or carbon spars) and ect....

Dec 02, 2003, 04:05 PM
Proud to eat Kraut ;-)
Julez's Avatar
Dont worry about weak spots, you dont need to reinforce anything. i saw it flying quite fast and nothing was bending. its made from a kind of elastic styrofoam, seems like a mix od EPP and normal styrofoam. but it does not have the rough surface of epp.
And it looks really big, the length is impressive. There is my dealer on the pic:
Dec 02, 2003, 06:10 PM
Senior Member
zagisrule!'s Avatar
Where can I get one in the US?
Dec 02, 2003, 09:12 PM
Registered User
Don Sims's Avatar
Great review Mike!! I really enjoyed it. That is a really interesting looking plane!!

Zagis, I saw them in the Hobby-People cataloge. You might check their site.
Dec 02, 2003, 10:36 PM
"Bible Thumper"
AMTJIM's Avatar
Horizon and Dymond have them as well. They are expensive from horizon if you orde them yourself, go through a dealer.
Dec 03, 2003, 04:49 PM
A Few Sandwiches Shy
RMason's Avatar
I love mine. It sure is a real attention getter out at the field. Even the gas guys stop to watch. You can really change the loks by adding a canopy to the top of the fuse. I stuck Yoda in mine.

Dec 05, 2003, 02:24 PM
Electric Coolhunter
Thomas B's Avatar
Michael, your early posts before the review inspired me to order one. Your review is very good. I only had one nit to pick.

In the review, you refer to the model as having a delta wing. I don't feel that this model has a delta wing. A good bit of the total wing area is found in the plug on wingtips and not in the highly swept center section. It would be more accurately described as a "cranked arrow" type of wing, or perhaps swept wing with a large leading edge strake.

If someone were describing the aircraft in a technical sort of way, I think the entry might well read: Canard with aft swept wing, with a large LEX (leading edge extension)

Once again, great job on the review! I plan to maiden mine tomorrow.
Latest blog entry: 2014 events and travel
Dec 05, 2003, 05:50 PM
Registered User
Michael Heer's Avatar
Good luck on your maiden flight! I hope you love yours as much as I love mine! Mike
Dec 06, 2003, 09:07 PM
Electric Coolhunter
Thomas B's Avatar
It flew GREAT and was well received. Majestic in the air and great fun to fly!
Latest blog entry: 2014 events and travel

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