RC India

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

Looks like you got your "adrenaline on the rocks" ;D
Congrats on a successful maiden :thumbsup:

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 ?
 :thanks:

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 ;D

got the motor today and other nick knacks...:thanks: 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 ;D

@ #9
Building and then flying is yet another  :thumbsup:

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,  :o 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' :salute: 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  :thumbsup: :salute:

Wow how easily you have explained, flyingboxcar  :salute:

You guys are rocking this forum.

I, going to become a Surgeon sooner than expected. ;)

Jai Hind
All the Best
Akshay

Could be the motor has excessive downthrust needing up trim for level flight at higher throttle settings. This would then require down trim with the motor cut or at idle.

good point, on my way to check it on the field

Hi Augustinev/flyboxer,

finally I've started building the YAK 54  bought from Pravin.

Presently received the below consigment from HKB (after 25 days)

TR 35-36B 1300kv Brushless Outrunner (Eq:2814)
BATTERY Turnigy 2200mAh 3S 30C Lipo Pack
TURNIGY TRUST 45A SBEC Brushless Speed Contr
APC style propeller 10x5-E
HXT900 9g / 1.6kg / .12sec Micro Servo -Still waiting for next consigment to come from HK along with batt .charger (consgment to arrive next or so).

Presently ,I don't have an 9in 9 inch extension lines  for rudder & stab,used 4 extension line ,& also no y connector for alerons but need these ,will check whether rc damaka has it ?

1) To start with : completed all servoes attachment drilling of small holes & fixing of 2 servoes.
(borrowed by my friend)

"Servo mount for elevator and rudder requires reinforcement, used CA and Soda (A little) " can you explain how was this done ?

2) Glued the elevator & rudder.with respect the wing tip to elevator with equal distance & also check that the wing  & stab are parallel to each other.

3) Wing joiner pipe (Surprise was 1mm lose was falling out of fuselage if tilted side ways,put a tape on it so it stays firm on both wings & the fuselage.

4) for engine mount ,wanted to mount the motor in front of the mount & not inside as I want to use the thread accessories shaft provided by the mfg ,if I mount the motor inside the mount then I have to use the thin shaft,what the correct way,new to electric.
 
" PLEASE mount motor onto the mount plate before you make the mount (Do not follow the book)".

5) Thanks to your son scale ,for the idea of installing battery is just great.Also the rubber trick for landing gears is well noted.

6) To keep the lateral balance, i marked all positions including esc and the battery position.
This mean to keep esc /battery in centerline of fuselage.

Hi flyingboxcar,

7) CG -mentioned in  manual -75mm from fuselage,will check on this after turning the plane up side down.

8)  Has the tail wheel been stuck in the rudder -very soft ,any better suggestion

tail wheel fix can be tricky, watch out


9) will reduce throws to 20 -22%

Do I need to adjust the trust line i.e two deg down and 2 deg right ,could I but a washer on upper bolts & on the left.

how did you install the ESC & RX ? Did you velcro them .
 
Any other suggestion is still welcomed.

regards
peter

Peter
A lot of water has flown under the bridge after that. let me cover a few more developments

(a) Keep the CG to 60 mm and not 75 mm, 75 mm is little too tail heavy, and it is also not the max thickness point, max thickness is at about 60 mm. keep it there, in spite of the forward batt, i had to add 32 gms of nose wt to adjust the CG, put it just under the cowling at six of clock position

(b) if you have silicon cloth piece shred it stick it with quickfix, where you are going to mount he servo sprinkle some baking soda and pour super glue, (A trick taught by Israelis) be sure wear a mask, if fumes enters your nostrils you will feel giddy, soda and super glue (Fevi Kwik) reacts and gives out pungent odour, , the reinforcement becomes like a rock.

(c) epoxy and alcohol (Not the drinking kind) mix it and brush it in all joints to reinforce it, leave it for 48 hrs, joints are quite flimsy and glue used is inadequate. for inaccessible places like the fuse and the emphenage use syringe

(d) Motor mount is SH@#t, see youtube there are a lot of options available for holding the motor mount properly, use the one that suits you, i fixed four nuts and bolts to reinforce it.

(e) do not run the motor at full throttle on ground, since the model is not getting pulled on ground max load comes on the motor mount, it can even fly off and you may look for it in the bushes of airoli and never find it (JPUL)

(f) be sure to keep the throw to bare min for maiden

(g) 'Y' connector is not required, if you have a good radio, you can convert it into a flaperons for a real low speed flight and landing, and you can also configure it for air brakes and of course snap roll, all of it it does decently well

(h) Given enough motor power it can even be hand launched.

(i) Double sided tape on either side of the fuse wall (As i am sharing the ESC)

That's all i can remember now

All the best for your maiden

maiden of my extra 330 changed after reading ur post,some more work to finish in the area of reinforcement

Santhosh

all the best, your Extra is aerodynamically a better machine

Hi Augustinev,

Honestly -thanks for your reply-Sorry for the late reply phones were dead for 2 days,come late from work.

Yes I was finding the CG between 60 to 65 mm after placing the battery on the fuselage with 2 rubber band & moving it back & front. since I have  heavy esc & battery ,motor 3536 1300kv that should do the trick.

will check some videos on you tube boss for motor mounting but I I'm still not clear on the mount & had to stop my building reason i want the motor to e mounted in from of the wooden mount & not inside it as shown in the catalog-will that play a Major role of change in the CG.

It also came to my mind to put double sided tape on the ESC & Also the battery with a tie rap.

Will keep you posted.

regards
peter