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FLIGHT NOTES

The Yak-55M EP is a great-flying model that flies smoothly 
and predictably. The Yak-55M EP does not, however, possess 
the self-recovery characteristics of a primary R/C trainer and 
should be flown only by experienced R/C pilots.

CAUTION (THIS APPLIES TO ALL R/C AIRPLANES): If, 
while flying, you notice an alarming or unusual sound such 
as a low-pitched "buzz," this may indicate control surface 

flutter

. Flutter occurs when a control surface (such as an 

aileron or elevator) or a flying surface (such as a wing or 
stab) rapidly vibrates up and down (thus causing the noise). 
In extreme cases, if not detected immediately, flutter can 
actually cause the control surface to detach or the flying 
surface to fail, thus causing loss of control followed by 
an impending crash. The best thing to do when flutter is 
detected is to slow the model 

immediately

 by reducing 

power, then land as soon as safely possible. Identify 
which surface fluttered (so the problem may be resolved) 
by checking all the servo grommets for deterioration or 
signs of vibration. Make certain all pushrod linkages are 
secure and free of play. If it fluttered once, under similar 
circumstances it will probably flutter again unless the 
problem is fixed. Some things which can cause flutter are; 
Excessive hinge gap; Not mounting control horns solidly; 
Poor fit of clevis pin in horn; Side-play of wire pushrods 
caused by large bends; Excessive free play in servo 
gears; Insecure servo mounting; and one of the most 
prevalent causes of flutter; Flying an over-powered model 
at excessive speeds.

The Yak-55M EP is easy to fly and does not have any bad 
flying traits. It requires only a short distance for takeoff. In 
the air, you will notice that it does have some pitch coupling 
with rudder. This can be easily mixed out with a computer 
radio. We recommend taking off on high rates. Once you feel 
comfortable with the high rates, check out what you can do 
with the 3D rates. 

We do recommend that a flight timer be set up on your 
transmitter to avoid a dead stick when the motor battery 
dumps and the ESC cuts the power to the motor. Landing 
the Yak-55M EP is easy. As the power is reduced for landing, 
the speed bleeds off quickly. It may take a couple of landings 
to get the feel of how quickly the plane slows down. We found 
that the plane lands as if it has flaps. 

Have a ball flying the Yak-55M! But, remember to always 

stay in control and fly in a safe manner.

GOOD LUCK AND GREAT FLYING!

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Summary of Contents for YAK-55M Yakovlev

Page 1: ...package the problem will be evaluated as quickly as possible Length 47 in 1195mm Radio 4 Channel minimum or 5 Channel with mixing for separate ailerons Motor ESC Prop RimFire 32 42 50 800 Wingspan 51...

Page 2: ...eat Planes web site at www greatplanes com Open the Airplanes link then select the Yak 55M EP ARF If there is new technical information or changes to this model a tech notice box will appear in the up...

Page 3: ...05mm servo extensions are required for the rudder and elevator servos If you are using a radio system that does not support mixing functions a Y harness will also be required to connect the aileron se...

Page 4: ...ly upon your experience to decide what type of glue to use When a specific type of adhesive works best for that step the instructions will make a recommendation We recommend 30 minute epoxy to install...

Page 5: ...rs and payments by personal check to Hobby Services 3002 N Apollo Drive Suite 1 Champaign IL 61822 Be certain to specify the order number exactly as listed in the Replacement Parts List Payment by cre...

Page 6: ...ger than the S3115 servo If the S3150 servo is installed both ends of the aileron servo opening will need to be trimmed approximately 1 32 1mm 3 Install the servo into the servo opening Drill through...

Page 7: ...silicone clevis retainer over the clevis With the aileron servo and the aileron centered mark the aileron pushrod where it crosses the aileron servo arm Make a 90 bend at the mark Cut the pushrod 3 8...

Page 8: ...bottom of the stabilizer just outside the cut covering Insert the stabilizer in the fuse so that part of the bare wood is showing Apply 30 minute epoxy to the wood top and bottom Slide the stabilizer...

Page 9: ...line 2 Install the three CA hinges into the rudder Insert the tail gear wire in the rudder and check the fit of the rudder on the fin Use pins to hold the CA hinges in position 3 Coat the inside of t...

Page 10: ...he threads of the SHC screws 5 Repeat steps 1 4 for the left main landing gear Install the Motor The Yak 55M EP has been designed to use the Great Planes RimFire 32 Outrunner Brushless motor If you wi...

Page 11: ...tall and center the servo arm 5 Thread a nylon clevis 16 turns onto a 2 56 x 10 254mm wire pushrod Connect the clevis to a nylon control horn Using the elevator pushrod position the control horn in li...

Page 12: ...ition the control horn so that it is centered on the line from the previous step Mark the location of the mounting holes onto the rudder Drill a 1 16 1 6mm hole on the marks Do not drill completely th...

Page 13: ...loop material around the battery Trim off the excess material Install the Cowl 1 If you have installed the recommended RimFire 32 brushless motor the cowl louvers will need a 1 3 4 38mm to 1 7 8 48mm...

Page 14: ...4 CHANNEL RADIO SET UP STANDARD MODE 2 3 Make certain that the control surfaces and the throttle respond in the correct direction as shown in the diagram If any of the controls respond in the wrong d...

Page 15: ...ate to fit your motor s prop adapter Install the spinner back plate propeller with washer and prop nut and the spinner cone Secure the spinner cone to the back plate with two 3 x 12mm sheet metal scre...

Page 16: ...ed to support weight Begin by placing incrementally increasing amounts of weight on the fuse over the motor box until the model balances Once you have determined the amount of weight required it can b...

Page 17: ...sand the propeller may throw such material in your face or eyes Keep your face and body as well as all spectators away from the plane of rotation of the propeller as you run the motor Keep these items...

Page 18: ...ment listed in the complete AMA Safety Code 9 Under no circumstances may a pilot or other person touch a powered model in flight nor should any part of the model other than the landing gear intentiona...

Page 19: ...it will probably flutter again unless the problem is fixed Some things which can cause flutter are Excessive hinge gap Not mounting control horns solidly Poor fit of clevis pin in horn Side play of w...

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