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Cermark Yak 49" ARF Review

Cermark has released a new 49" Yak Sport/3D model to the market. Mike Llewellyn looks at new ARF!

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Introduction


Wingspan:49"
Wing Area:~465sq inches
Wing type:Built up - Symmetrical
AUW weight:Advertised 37-42oz Actual 48oz
Length:47.25
Wing loading:15 oz/sq. ft.
Servos:4 Micro/Mini
Transmitter:Spektrum DX7
Receiver:Spektrum AR6200
Battery:3s 2200 mAh (used 3s 3000 pack)
Motor:Neodym 15
ESC:Castle Creations 45amp Phoenix ESC
US distributor:Cermark
ARF Price:$149.99

Cermark has an all new line of 3D capable ARF models on the market. The 49" EP series has a number of very sharp looking models including:

  • Edge 540
  • Yak 54
  • Sukhoi 26
  • Extra 260
  • Katana

The review package for the Yak shipped from Cermark, and it arrived double boxed and in great shape. It was well packaged and very well protected: All of the ARF parts are individually plastic wrapped and separated with cardboard sections which really helped to protect them in shipping.

Kit Contents

Kit included:

  • Stunning pre-covered built up balsa and ply fuselage
  • Built up wing and tail surfaces, covered and ready to go
  • Clear canopy with magnet attachments
  • Factory slotted hinges ready for gluing
  • Hardware (push rods, torque rods, keepers and horn)
  • Stick on type markings
  • Picture assembly guide

Yak requires:

  • 40+amp ESC
  • 3s LiPoly battery (2200 mAh recommended but balance may be an issue)
  • 4 Micro servos
  • Receiver
  • 4 channel minimum transmitter

Included for this review:

Assembly

The Yak is a true ARF model with nearly all of the tough work already done for you. These ARFs are highly prefabricated, covered and largely built. The Yak was ready to fly with just a few hours of work.

Done by the factory:

  • Surfaces hinged ready for included CA hinges and glue
  • All surfaces covered
  • Factory paint on the cowl

The builder needs to:

  • Install the servos
  • Install the motor and ESC
  • Install and align the tail surfaces
  • Install the battery/ESC tray
  • Apply self adhesive decals

Wing

The wing on these Cermark EP 49" ARF series models are all very similar. The wing halves have cutouts for small 9-11g servos. I used Hitec HS-65s in the Yak.

The wings join to the fuselage with included CF tubes.

The Yak has tabs that slide into the center section of the fuselage and secure with bolts and pre-installed blind nuts in the fuselage center section.

Factory installed wood servo mounts are in each wing half. The factory cut opening on both planes was perfect for the Hitec HS-65 servos that are recommended for use.

Each wing panel and aileron receives a servo for direct short linkage setup, which is my preference.

The included fiberglass horns on the Cermark Yak 54 were much thicker than the milled slots on any of the control surfaces. It was necessary to either enlarge those holes or sand the base of the horns to fit in all of the control surfaces. It would be nice to see the slots milled properly from the factory.

Fuselage

The fuselage on the Cermark Yak 54 has scalelike outlines, and it is certainly not easy to replicate the rounded fuselage of the Russian Yak 54. It looks really great. Similarly, the covering and attractive red and white scheme on the Yak looked fantastic. As is common with ARFs, there were a few wrinkles but a quick touch up with a covering iron did the trick.

The Cermark Yak 54 included many laser cut lightening holes which really helps to keep the overall weight down.

Installation of the servos was standard. The elevator servos are placed in the rear of the fuselage for a short direct linkage to the elevator surface. The rudder servos used include pull-pull cable setups. This pull pull setup has the servo located in the center of the fuselage near the CG.

The pull-pull cable system uses EZ type connectors. While the setup appeared to be snug, I found that after working the servo for some time the cable began to slip - good to find that out on the ground! I used small plastic tubes to increase the mass of material, enabling the EZ connector screws to grip the cable properly. Please check yours!

Landing gear plates and blind nuts were factory installed on the Cermark Yak 54. Two of these were not properly threaded which created difficulty in threading the included bolts. Higher quality hardware and parts control would be welcome on these planes.

The motors mount to the rear of the wood motor mounts that are factory built. The motor cage assembly must be attached to the fuselage former.

Also included were some vacuum formed air diverters to direct airflow from the cowl openings directly to the motor, ESC and battery. These were a great touch.

It quickly became apparent that the battery tray in the Yak simply did not extend far enough into the nose to attain the recommended CG. I used some of my 1/8 lite ply to extend the tray.

I also used the heavier and larger 3000 mAh pack on the Yak to help with CG. Attaining the proper CG with the recommended 2200 packs may be difficult. Relocation of the elevator servo and use of a heavier power system will assist if you choose to go that route.

Canopy

The Cermark Yak 54 includes large, magnet secured canopies that double as battery hatches. The hatches are secured with magnets and recommended screws.

I found that the recommended screws are necessary in high alpha knife edge flight at higher than about fifty perfect power settings. I was shocked by this as the included magnets are very secure, but this just shows the significant flight loads on the canopy in KE flight.

Tail Assembly

Tail assembly on the Cermark Yak 54 was completely typical. The elevator servos mount in the tail for short linkage setups. While these direct short linkages are my preference as they allow for short, direct linkages, it does make the aircraft tail heavy with the recommended 3s 2200 class battery packs.

The only snag I had on the tail was that the included horns were again too thick for the milled areas in the rudder an elevator. For the elevator I simply sanded the horn thinner. I did not want to do that for the rudder horn so I increased the cutout in the rudder surface.

Power system

The Cermark Yak 54 was powered with the new Neo 15 motor. I used the highly capable Castle Phoenix 45 for the Yak. The Phoenix controllers are excellent and have never let me down.

Amp draws

The Neo 15 motor and Castle Creations 45 Phoenix running on 3s Common Sense RC 3000 packs produced the following static results:

Motor statistics
Propeller Amps Watts Voltage
APC 12x6 43 452 10.5v

This Neo 15 and Castle 45 power system provided good 3d power for the Cermark Yak 54 . The Neo 15 at 900KV easily would accommodate a larger propeller for more 3D pullout power if desired. A 13x6.5 worked well but drove the amp draw past where the Common Sense pack was totally happy.

Battery

The 3s 3000 MAh Common Sense RC pack was used in the Cermark Yak 54 with great results. It is heavier than the Cermark recommended 2200 3s packs but the Yak handled the weight just fine. The Common Sense RC 3000 mAh pack weighs about 10oz vs about 6-7oz for 2200 packs.

Completion

The finish on the Cermark Yak 54 was well applied, and it looked fantastic. As is common with the long transit overseas, the Yak came with a few wrinkles. A hot covering iron had those wrinkles gone quickly.

CG

In order to reach the CG it was necessary to use larger capacity and thus heavier packs. They are about 3-4 oz heaver than recommended, but that was worth it in increased flight times.

Rates and transmitter setup

I used my trusted Spektrum DX7 transmitter for the Cermark Yak 54. I used the full range AR6200 receiver. Rates were set as recommended in the manual and worked fine for me. Rates are very much a personal preference so adjust yours accordingly!

Flying

I know many of you will want a 3D assessment, so I enlisted the help of Josh (BoneDoc here on the forums) as he is a highly gifted 3D pilot. Overall Josh was happy with the Yak and reported that it had very little if any roll coupling. He noted a minor wing rock and a tuck to the canopy in Knife Edge. That has since been resolved as I have moved the pack further back. Now it exhibits very little knife edge coupling.

Josh did note that it needed every bit of power it had, and he wanted a bit more for pullout. A larger propeller for a bit more power would help there. The Neo 15 motor was barely warm indicating it was certainly not overly taxed.

Thanks to Josh for being willing to fly the Yak, and you can see his talent in the 3D video.

If your interest lies in a good sport aerobatic airplane, the Cermark Yak 54 easily performs anything thrown at it. In fact, it would make an excellent IMAC practice plane as one with expect with the full scale heritage.

Of note, the Yak had an issue after about 40-50 flights. The motor actually pulled through the firewall with the screws still attached. Thankfully I was able to land the aircraft without further damage, but it completely destroyed the motor mount and the former where the motor cage mounted to the fuselage.

I discovered that when I drilled for the Neo 15 motor the material was simply not thick enough to accommodate counterdrilling.

I would recommenced re-reinforcement of the firewall with a layer of 1/16" aircraft plywood face plates. The use of washers would help distribute the load better as well.

Takeoff and Landing

Power levels on the Cermark Yak 54 was very good, enabling very short takeoffs and landings that allowed me to float in slower than any trainer! The Yak is an excellent flying airplane.

Special Flight Characteristics

The Cermark Yak 54 is fully 3D compatible, and the control surfaces easily accommodate 3D type throws. I fly the Yak as a sport ship, and I can honestly say the Yak is a blast to fly. With the light wing loading it lands like a feather on a stick. It recovers from snap maneuvers almost instantly. The Yak can be pushed to stall, but it recovered quickly and without any drama.

Aerobatics are insane, especially with high or 3D rates. Knife edge flight is a blast, but you will need a latch or the recommended canopy screws because the canopy will eject in high alpha knife edge. Snaps and spins are crisp, and they stop very near instantly. The Yak required a rearward CG adjustment to keep the KE tuck out, but that too is common in setup of this type of aircraft. The recommended CG is certainly an excellent starting point.

I snapped some pics with the Nikon D60 while Josh was flying the Yak.

Recommended power system

The Neo 15 has good power as well. A slightly larger prop for more pullout power in 3D would have been welcome - just watch those AMP rates! The motor will certainly take it but the battery needs to be very capable.

Is this plane for a beginner?

The Cermark Yak 54 is not intended for the beginner. The Yak 54 is a highly responsive 3D aircraft. While the rates can be toned down for sport flying, they are suited for pilots with adequate stick time.

Flight Video

Downloads

Yak - 3D flight  22.56 MB

Conclusion

Even with the construction issues, the Cermark Yak 54 is simply a blast to fly. The Yak is fully 3D capable with large control surfaces that are factory beveled for high rate control throws of nearly 45 degrees. The Yak goes to the field regularly - a sign of a good flying airplane! The Yak certainly goes where you point it and it leaves me grinning.

Pluses:

  • Excellent looks
  • Light weight
  • Quick assembly time
  • Flight performance

Minuses:

  • "T" blind nuts for the landing gear were not properly tapped
  • EZ type connectors for pull-pull setup did not properly grasp cable
  • Horn material too thick for cutouts
  • Balance issues with the recommended 3s battery packs
Last edited by Angela H; Jan 13, 2009 at 01:01 PM..

Discussion

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Old Jan 13, 2009, 03:47 PM
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Paul 1968's Avatar
UK
Joined Oct 2008
1,390 Posts
pda4you, you have produced an excellent and very accurate review of this model. I have not yet experienced any firewall issues, but I do agree that these models present outstanding value for money. They were once considered a well kept secret but you have let the cat well and truly out of the bag.

Paul
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Old Jan 13, 2009, 03:52 PM
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theKM's Avatar
central PA.
Joined Sep 2004
20,185 Posts
certainly some nice flying by the boney doc in that one!
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Old Jan 13, 2009, 03:59 PM
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pda4you's Avatar
USA, TX, Trophy Club
Joined May 2002
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Thanks Paul....

Yep a HUGE thanks to Josh "Bone Doc" for the 3D flying. He is an amazingly talented pilot. That was a fairly windy day too - so he was coping with that. Can you tell he likes rolling circles?

It is a great flying plane - no question - even for the sport gang too. The Yak 54 goes to the club field every time I fly the sign of a really good airplane.

Mike
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Old Mar 16, 2009, 12:52 PM
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MJ-MERLIN's Avatar
deepest darkest suffolk UK
Joined May 2007
469 Posts
Hi I'm just about to get one of these planes and I was considering motor choices
Did you have to add any additional weight to your plane to get the CofG right using the neo 15 motor ?
A guy from another thread said that he needed to add 1 zo (28g) on the 260 when using the Neo 10 (143.4G) motor
also have you got plenty of room forward and aft of the battery to adjust the CofG ?

many thanks

MJ
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Old Mar 16, 2009, 01:00 PM
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Paul 1968's Avatar
UK
Joined Oct 2008
1,390 Posts
Depending on motor and battery choice, you may need to shuffle the battery around to achieve the correct CG. I'm using a Hacker A30 14L with Tornado 2200 3 cell packs . You can push the pack a long way forwards into the motor cage to get a forward CG. By the same token if you prefer a lively model the battery tray is very long and will allow you to pull the pack back to touch the rudder servo if you wish. I use the same power set up in my Extra 260 without need for any extra ballast and it is superb.

Paul
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Old Mar 17, 2009, 03:16 AM
Team 3DHS
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San Antonio, TX
Joined Sep 2004
15,632 Posts
Great review Mike. The pilot was a hack, but the review was excellent .
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Old Mar 17, 2009, 07:32 AM
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andy walling's Avatar
USA, CA, Huntington Beach
Joined Aug 2006
240 Posts
Nice job on the sticks Josh and great review...
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Old Mar 17, 2009, 12:06 PM
Wannabe 3D Pilot
flyracer's Avatar
USA, AZ, Chandler
Joined Nov 2006
1,192 Posts
I opted for the 70" version of the Yak from Cermark (same color scheme as the little 49" kit).... I am using a power 110 with a 80amp HV ESC and 8s 3300mah (2x4s) pack.... looks like the APC 18x10 prop is to much.... whatsup meter is showing 60amps at mid throttle. I've got a 17x8 prop on order and hope to do the maiden flight this weekend.

-Flyracer
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Old Mar 25, 2009, 05:22 PM
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MJ-MERLIN's Avatar
deepest darkest suffolk UK
Joined May 2007
469 Posts
just a quick note.
the rudder servo hole on my yak wont fit a HS82mg its cut to fit an HS65.
gonna have to open it up or get a HS65 for it.

wadda you guys reckon
cut it or take the servo back to the shop and swap it for a HS65mg ?

MJ
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Old Mar 25, 2009, 05:25 PM
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Paul 1968's Avatar
UK
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I have an HS65 in mine. It seems up to the task but perhaps the HS65 MG would be a better choice for durability, also because it's marginally heavier you will have fewer problems achieving the correct CG.

Paul
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Old Mar 25, 2009, 05:36 PM
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MJ-MERLIN's Avatar
deepest darkest suffolk UK
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wow that was quick !
ill have to remove this much so still plenty of timber there.

the HS82mg is even heavier !

MJ
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Old Mar 25, 2009, 05:44 PM
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Just cut it out - that is what I used..... Works fine.

Mike
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Old Mar 25, 2009, 05:51 PM
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flyracer's Avatar
USA, AZ, Chandler
Joined Nov 2006
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Quote:
Originally Posted by MJ-MERLIN
wow that was quick !
ill have to remove this much so still plenty of timber there.

the HS82mg is even heavier !

MJ
HS65MG = 0.39 oz weight & HS82MG = 0.66 oz weigh

HS65MG = 25oz torque @ 4v & 31oz torque @ 6v
HS82MG = 38.8oz torque @ 4v & 47.2oz torque @ 6v

HS65MG has bearing support at top.... HS82MG does not. Over time, I picked up some wiggle in the HS82MGs

-Flyracer
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Old Mar 25, 2009, 06:04 PM
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moreno valley california
Joined Jun 2008
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regarding the CG - my 260 flew great with the battery right on the tray, (using the 25 900) but the Edge required it be pushed into the motor box - the first flight with it on the tray was somewhat exciting as the CG was biased rearward. A friend of mine has the yak and had to move things a bit also. I have (at Steve's recommendation) an 81MG on the rudder, and it dropped right in. there are certainly other, if not, better choices for servos, but this is a good start for the budget minded. i recently reviewed the edge in another thread - not as detailed as this one.
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