This is the build log of YAK 54 EP. (http://flying--rc.blogspot.com/2010/10/yak-54-ep.html)

This was easy build, build to maiden was less than 4 hrs. Model was from Pravin, since HK and its motor took some time (Yet to reach me), decided to go with EMAX 2218 (http://www.rcdhamaka.com/index.php?main_page=product_info&cPath=58_59_93&products_id=517). a few points for consideration

1. you will require 9 inch extension lines two of them for rudder and elevator servos.
2. Used nine gram servos from VK
3. Slot for 9 gram servo was small by 2 mm, had to sand it a bit.
4. Servo mount for elevator and rudder requires reinforcement, used CA and Soda (A little)
5. Wing joiner pipe was good 2mm bigger in dia than the slot provided, I put the wing joiner in the deep freezer for a while, fitted easily and after warming back to room temp locked into place.
6. PLEASE mount motor onto the mount plate before you make the mount (Do not follow the book)
7. Main under carriage is weak, planning to put a rubber band across both legs as a shock absorber.
8. if you put any battery onto the wing joiner as shown in the book CG will be 95 mm as opposed to 75, battery has to go in front of the access door , of course it will also depend on the motor, point is check the CG smaller the aeroplane , critical is the CG.
9. lateral balance is exceptional
10. to keep the lateral balance, i marked all positions including esc and the battery position
11. marked CG line on the wing root and the wing tip
12. tail wheel fix can be tricky, watch out
13. do not use force to tighten anything, balsa is soft, screw will eat into the balsa
14. use thread lock
15. file the control rod at the portion where collet will contact the rod
16. after fixing everything bend the rod outwards instead of cutting, with this even if your collet falls of the rod will stay.
17. used a 10x6 prop.
18. elevator throw of 35 mm is way too excessive for maiden keep it at 20-22mm, or have dual rate.
19. because of the huge space behind the prop esc and the battery was cool, downside is even 10x6's prop wash for a hover is insufficient, i think, see for yourself.
20 Flies beautifully.

more logs

Decided to do night maiden with limited twilight, and head light of my gypsy, high up was not a problem as the sky was still slightly lighted (See image). coming into land the color of the model and the tree line made the model disappear. Went around and brought her close, laid down on the ground to skyline the model. Flare out touch down was purely on feel. Hover was OK, prop wash, I think was less, stall turn is superb, does not wallow vertically down. rudder power is good can do a good knife edge (Did not try). More on other aeros later.

Happy Flying

Quote from: augustinev on February 07, 2011, 09:20:05 PMcoming into land the color of the model and the tree line made the model disappear

Looks like you got your "adrenaline on the rocks"
Congrats on a successful maiden

truely, in hind sight, shouldn't have done a night maiden, what if flareout and Touchdown did not go well ?. then what's life without a little thrill ?

8. if you put any battery onto the wing joiner as shown in the book CG will be 95 mm as opposed to 75, battery has to go in front of the access door , of course it will also depend on the motor, point is check the CG smaller the aeroplane , critical is the CG.

I think its the motor weight ,the new motor 3536 should do the trick since its a heavy 159g motor and then the 2200 mah onto the wing joiner should give you a better cg,the motor dispatched from Bombay days ago  haven't you received it yet 

Folks,
What is the AUW of the current setup? Praveen's site only lists as weight being 800gm, not sure whether it is AUW or not

current setup AUW with 2200 mah lipo (From VK) with 30 amps mystery esc with anderson-xt 60 adapter (A contraption i made to use both anderson and xt60 batt) is 846 gms (With decals).
Did  another sortie, in the morning, knife edge is awesome. going to try it in a park, will upload some videos.

great.......... waiting for the videos, i too have the same model from praveen planning to build

'Building' is a different hobby, flying is different hobby, both requires different set of skills....so says Bhole Baba

got the motor today and other nick knacks... Pravin

Hi Augustinev ,

The model looks great,As i also spoke to Praveen on this same model.Thinhing  of buying it.

Thanks for your detailed guidance build log for YAK54 EP 

Have you any Videos uploaded

regards
peter

peter, you can call me, pm me, anytime

@ #9
Building and then flying is yet another 

I love this Hobby, what an amalgam of flyRc, RCD & VK

Dear All

Thanks for the support

regards peter

Thanks augustinev,
                        This detailed Build log will certainly going to help people, who want to build YAK-54. Like your idea of putting metal tube in refrigerator.

                           Building and flying, it's like Physician and Surgeon turned into one.

LEDs yes, want to build it up slowly, after that crazy night flying i have decided to do it the professional way, so ordered slow slick (http://cgi.ebay.in/GWS-SLOW-STICK-GREAT-BEGINNERS-MORE-POWERFUL-/110631357775?pt=LH_DefaultDomain_203&hash=item19c2248d4f) from mr sai, some leds will go on that, them may be Pilatus Porter (http://flying--rc.blogspot.com/2010/10/pilatus-porter-ep.html) and I'll take  it from there, actually moon phase is not a problem, when there is no moon things tend to get slightly more dark.
Surgeon Physician analogy was gr8

With the under powered motor she was tail heavy, at low speed she would go tail up, there a small mod to push the weight fwd, cut my sons scale and glued it, wheels were getting into 'Vishram' from 'Saavdhan',you know what i mean,  therefore i learnt this rubber band trick from a veteran, now whenever she lands a little hard she bounces back into the air, always in 'Saavdhan' I flew Her at Fwd most and Aft Most CG Positions which can be comfortably flown.

Since dam (Intentional) Chinese don't write them clearly, i have marked it, you can see it with respect to the cover and mark it in your model. (Measuring it on a cambered wing can be tricky, you can make a mistake) 2200mah is giving 15 mts comfortably, most of the time on 1/2 throttle, except in case of extreme 3D.

Gusty,
All wings (except flat plate) would be cambered, therefore the correct way to measure and mark the CG is
1. With the model assembeld, and standing on its own (for ones without a UC to be propped up) put a flat object vertically and perpendicular to the  LE of the wing.
2. Place a ruler abutting the flat surface you have placed in front of the LE.
3. Now measure the required distance and mark the location/s.
If you do not want to spoil the surface detail on the model, stick a piece of tape and mark the CG on the tape. The tape can be peeled off once the job is done

Also I am somehow not convinced about your statement on the model going tail up at low throttle due to tail heaviness. That some how looks like a function of either power or thrust angle combined with decalage.
A model pitchng up on higher power and reverse on low power would need the decalage and thrust angles to be adjusted and not necessarily the CG.
If you only see the tail going up (i.e nose going down) on low power (and not the reverse when power is applied) it could indicated nose heaviness and not tail heaviness.  

whats a crazy night maiden flight without a crazy pilot?

Got that , in fact , Dave (Rcpowers) explains it beautifully in a layman's terms,( two deg down and 2 deg right, stick a toothpick). i did that to my motor mount got the thrust line slightly down and to the right, (Caters for prop wash and gyroscopic effect of the prop)

what i am talking about it is engine cut gliding down, i am having to push fwd, indicating CP is on or slightly behind CG, because, 'high alpha CP' moves back upto the point of stall. where it moves fwd rapidly(the reason for nose drop at stall, for a cambered wing). CG marking i did it with a home made plumb line with the chordline near parallel (Using my inclinometer on the iphone).

Static margin was less, manoeuvre margin even less for the specified CG, i guess i used a lighter motor.

Thanks , i learnt some more today

Yes if one has to push down to keep from stalling at low throttle, that would indicate rearward CG.
But if you have to push down to keep the nose level at high throttle that indicates upthrust on the powerplant or decalage issues apart from possible CG issue as well.

got that  

Quote from: augustinev on February 18, 2011, 07:01:06 PM

what i am talking about it is engine cut gliding down, i am having to push fwd, indicating CP is on or slightly behind CG.