Legacy Avi­a­tion Mus­cle Coupe

This great-look­ing scale air­craft is a blast to fly

Model Airplane News - - CONTENTS - By John Kauk

Ex­treme Flight RC is well known in the 3D aer­o­bat­ics world for light, well-made mod­els ca­pa­ble of the most ex­treme aer­o­batic ma­neu­vers. For scale en­thu­si­asts, its Legacy Avi­a­tion brand of­fers a range of civil­ian gen­eral avi­a­tion and vintage mod­els. At eWeek last year, I watched a new Legacy Avi­a­tion model fly. It looked an aw­ful lot like a Mono­coupe 90 to me, and I re­ally liked the se­date, grace­ful way it flew. De­signed for re­lax­ing sport flying, it’s called the “Mus­cle Coupe,” and I picked one up at The Toledo Show ear­lier this year. I also got one of the rec­om­mended Torque Rev­o­lu­tion mo­tors since I’ve had good ser­vice from the same mo­tor in the Bush­mas­ter, and I knew it would pro­vide plenty of power for the lighter Mus­cle Coupe. I don’t of­ten fly from wa­ter, so I passed on the op­tional fiber­glass floats, but I can say they’re beau­ti­fully made and quick and easy to in­stall.

UNIQUE FEA­TURES

As I un­loaded the well-packed box, I couldn’t help but no­tice how nicely the parts were cov­ered. On ev­ery piece, the cov­er­ing was tight and un­wrin­kled, and the stripes and graph­ics were per­fectly ap­plied. As I un­packed the parts, I ran a cov­er­ing iron over all the seams and stripes just to make sure they were well sealed. I then took a bot­tle of thin CA and went over all the wood joints I could reach, es­pe­cially those in the mo­tor box and for­ward fuse­lage.

Assem­bly starts with the wings, and there are no sur­prises in the process. Fiber­glass con­trol horns are in­serted into slots us­ing medium CA and then the flaps and ailerons are hinged with CA hinges. Servo in­stal­la­tion is straight­for­ward, fol­low­ing the di­rec­tions in the man­ual. I used Hitec HS-7245MH ser­vos all around, for a to­tal of six ser­vos. I found the an­odized alu­minum servo arms that came with the ser­vos to be per­fect for all the con­trol sur­faces. The kit-pro­vided ball-link con­trol rods are great, mak­ing a strong and tight con­trol link­age.

Fuse­lage assem­bly fol­lows, and again, there are no sur­prises. The land­ing gear and cover fit per­fectly, and the wheel pants are easy to in­stall. I liked the way the tail was de­signed, with the hor­i­zon­tal sta­bi­lizer slip­ping tightly into a slot and the fuse­lage re­cessed around the stab for a clean joint. Both parts are made of balsa wood, and the parts fit was tight enough that thin CA wicked in for a strong bond. The ver­ti­cal stab is sup­ported by two car­bon-fiber tubes and also fits into a re­cessed notch. The el­e­va­tor servo installs just like the wing ser­vos and is mounted right un­der the sta­bi­lizer. The rud­der servo mounts in the for­ward fuse­lage un­der the wind­shield hatch, with a long pushrod to the rear.

The rec­om­mended Torque Rev­o­lu­tion mo­tor mounts to the mo­tor box eas­ily us­ing the sup­plied ra­dial mount, and is per­fectly spaced for easy in­stal­la­tion of the fiber­glass cowl. I used a Cas­tle Cre­ations Edge 100 speed con­trol, and there’s plenty of room for mount­ing it un­der the bat­tery tray with cable ties. I in­stalled the cowl ac­cord­ing to the in­struc­tions and then bolted

on a Xoar 16x7 pro­peller, painted white with red trim to match the Coupe’s color scheme.

I did the assem­bly over the course of a cou­ple of evenings, and it took about three hours all told. Set­ting up and pro­gram­ming the Spek­trum AR9350 re­ceiver was fast and easy, and the plane bal­anced eas­ily at the rec­om­mended spot by sim­ply mov­ing the power bat­tery.

IN THE AIR

With tem­per­a­tures in the high 70s and a light wind al­most di­rectly down the run­way, it was a per­fect day for flying. After as­sem­bling the plane, I rechecked the bal­ance and con­trol­sur­face move­ment, and with it all in the “go” range, I took the Mus­cle Coupe out to the run­way.

The take­off run was straight, with a touch of rud­der re­quired as the tail came up. In a sur­pris­ingly short time, the plane was off the ground and climb­ing fast. When I re­duced throt­tle a bit and started an aileron turn to the left, I was im­me­di­ately re­minded of the line in the man­ual that states, “Just like the full-scale air­craft, co­or­di­nated rud­der/aileron turns are sug­gested.” Truer words were never writ­ten. With rud­der in­put, turns are as smooth and co­or­di­nated as they should be; with­out rud­der, they’re just un­gainly and ugly. In fact, it’s eas­ier to turn the Mus­cle Coupe with rud­der only than it is with aileron only.

Once I came to grips with that, the plane be­came a lot of fun to fly. It’s ca­pa­ble of do­ing any con­ven­tional aer­o­batic ma­neu­ver, and the abun­dant power makes for big loops and nearly un­lim­ited up­lines. With the sug­gested con­trol throws, the roll rate is re­spectable but not fast. It’s pos­si­ble to mix the flaps and ailerons to make full-span ailerons and in­crease the roll rate, but I pre­fer the more scale-look­ing, slower roll. After the aer­o­bat­ics tests, I slowed the plane and switched in half flaps, which caused the nose to raise a bit. Full flaps caused quite a bit more, so after the first flight, I mixed in a few per­cent of downel­e­va­tor to com­pen­sate. After about 10 flights to date, 6% down-el­e­va­tor with full flaps feels about right to me. Hav­ing flown the same power sys­tem ex­ten­sively in the Turbo Bush­mas­ter, I set the DX9 flight timer to six min­utes, shoot­ing for a stor­age-level charge after the flight. As the voice alarm sounded, I was in the down­wind leg of the pat­tern, so I called for a land­ing and set up no flaps and about 1/4 throt­tle after turn­ing to base and the Mus­cle Coupe was in a nice de­scent. I let it set­tle in, keep­ing it aligned with the run­way us­ing the rud­der. When the plane was about a foot off the ground, I cut the throt­tle and the plane set­tled in to a smooth land­ing. Back in the pits, a bat­tery check showed 3.9 volts per cell, so I knew I could add at least a minute to the flight timer.

GEN­ERAL FLIGHT PER­FOR­MANCE

Sta­bil­ity: The Mus­cle Coupe is fairly sta­ble but not so much that aer­o­bat­ics are com­pro­mised. If you put it in a bank, it wants to stay there un­til the pilot lev­els it out. Track­ing: Ground track­ing is solid. Take­off runs re­quire the usual tail-drag­ger rud­der cor­rec­tions to main­tain head­ing. In the air, the Mus­cle Coupe is an hon­est flier, not chang­ing at­ti­tude or di­rec­tion un­less com­manded. Aer­o­bat­ics: The Mus­cle Coupe is a fun aer­o­batic plane. It’s ca­pa­ble of all the scale aer­o­batic ma­neu­vers, and big, tall loops that seem to go on for­ever are a lot of fun. The roll rate is fast enough to be com­fort­able but not too quick. The man­ual’s sug­gested el­e­va­tor throws are per­fect; any more would cre­ate stall is­sues. Spins are easy and can be flat­tened nicely, and re­cov­ery is easy and hap­pens in about half a turn. Glide and stall per­for­mance: Power-off glides are fine, if a lit­tle steep. I keep some power on when on a fi­nal ap­proach to land­ing, pulling it off when over the thresh­old. Stalls are pre­dictable and straight ahead if the wings are level, with no sur­prises. Add power and keep the nose down for an easy re­cov­ery.

PILOT DEBRIEFING

All the flights since that first one have con­firmed my ini­tial im­pres­sions. Aer­o­batic flight times of around seven min­utes leave the Venom Power 6S bat­tery at a good stor­age volt­age. Rud­der is re­quired for smooth turns—in fact, flat turns are easy and fun to do. Pi­lots not com­fort­able flying with rud­der should mix rud­der to aileron and ex­per­i­ment to find the amount of mix that’s right.

I moved the cen­ter of grav­ity (CG) aft after a few flights, by mov­ing the 6S bat­tery back about an inch from the ini­tial bal­ance point. That puts the CG right around the cen­ter of the wing tube, which feels right to me.

Here the au­thor as­sem­bles the Mus­cle Coupe be­fore a flying ses­sion. Assem­bly is quick and easy: Two bolts se­cure the wing, then the two struts at­tach with three bolts each. (Photo by Ver­non Nel­son)

This photo high­lights the light­weight con­struc­tion of the fuse­lage. The fire­wall is re­in­forced with fiber­glass. The Torque Rev­o­lu­tion mo­tor pro­vides smooth and abun­dant power.

With the wind­shield hatch cover re­moved, the large bat­tery com­part­ment gives easy, com­fort­able ac­cess for chang­ing the Venom Power bat­tery and for ac­cess­ing the re­ceiver and rud­der servo.

The tab-and-slot assem­bly of the sta­bi­lizer to the fuse­lage makes for a strong joint, with a close fit for a good, thin CA glue joint. The balsa re­cesses in the fuse­lage fit the stab per­fectly, mak­ing an al­most invisible junc­tion be­tween the parts.

Ex­cept for the rud­der servo in the cabin, all the Hitec ser­vos are mounted ex­ter­nally. With 7.4V ra­dio power, they’re strong and fast, and the bal­llink con­trol rods that came with the model are slop-free and well suited to the task.

Both of the Legacy Avi­a­tion planes the au­thor owns came with a nicely made wing bag—a nice touch. Made out of re­flec­tive foil in­su­la­tion, it’s nicely stitched to­gether with two wing com­part­ments and a pouch for the wing tube.

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