Mr48Volts

I ordered one of these and a Saito 125 today...can't wait to build it.

So Spacey, what was your C of G with the 125????

Cheers

Scotty

Spacey

Hey Scotty,

It's been a while now but don't recall ever changing it from the back of the recommended spot? Get it there for starters, fly and adjust to taste.

Cheers,
Spacey

Mr48Volts

Spacey another question for you. I finished building the Yak today and was setting up throws as per manual and I have a question on the elevator travel. It says for low rates 12mm but for high rates 16mm???? With the aileron and rudder the difference between low and high rates is quite large, but it seems for elevator this amount is very small?

Maybe my manual is misprinted. Can you remember what throws you had set for hi and lo rates on elev??

Thanks in advance

Scotty

Spacey

I can't recall low rates no but it was fairly low. Probably around the manual's high rates. My high rates on elevator was maxed out though, much as I could get for 3D. If you're not going to 3D then the manual's throws is probably ok. To get the tail going anywhere though through 3D stuff you need to get it in the 45'~50' area.

Mr48Volts

Maidened the yak today in pretty breezy conditions, it handled the conditions perfectly and landed like a dream. On high rates it's a weapon , axial rolls and knife edge were great, didn't try hovering due to the wind... Only drama i had was on 2nd flight the carb line from tank split, the yak keep going but it started to surge so I landed it as quick as I could manage, took off the canopy to find the bottom of the plane covered in fuel....So it was a lucky escape... Got the yak home stripped the tank and batteries out, hit it with the Mrs hairdryer and will put it back together tomorrow..

But after 2 flights this thing on low rates lands great and seems like it certainly will be the goods...

Running Gear
13x6 MAS Prop
15% Nitro
Super Tigre G90 (my 1st Super Tigre, and what a joy to use)
OS * Plug
On Board Programmable Glow

Cheers

Scotty

My_Design

What do you think about flying this thing on an OS .46 AX 2-stroke with an 11x8 prop? I've got it in a phoenix Spitfire right now and was ahving serious trouble getting the beast in the air. But at 7 lbs it is almost 1.5 lbs heavier than the Yak.
I figure it should be good - I'm not looking to do heavy aerobatics, but am gaining interest.
This is the plane I'm getting and it looks different from yours:
http://www3.towerhobbies.com/cgi-bin...?&I=LXTRZ4&P=7


Edited for link and prop size

Spacey

Scotty: Very glad it went well apart from the little trouble! You're going to enjoy this model I'm sure, it's a great all rounder. Just remember to keep that canopy out of the sun at all costs!!! Hehe

My_Design: I don't think that's a good idea at all no. This model will struggle with that size motor very much. There's alot of drag on the airframe and it will bite (tip stall) a little if you slow it down too much without horses to keep it aloft. I'm sure it will fly with the .46 in a capable pilots hands in good conditions but I just wouldn't recommend it, you're not going to have any room to breathe or make mistakes in. Why don't you look into a nice .40 sized profile for that motor? You won't be dissapointed, pop over to the profile forums here on RCU and have a look.

My_Design

Thanks for the reply. I just noticed that mine seems much smaller than yours.[/size]
Here's the full specs from Tower:
REQUIRES: Engine: .40 - .46 cu in (6.5 - 7.5cc) 2-stroke
OR .52 cu in (8.5cc) 4-stroke
Muffler: Standard type included with engine
Radio: Four channel
Servos: Five, 42 oz/in torque minimum
(2-ailerons, 1-elevator, 1-rudder, 1-throttle)
Servo Extension: One 6" (152mm) for ailerons
Y-Harness: One for aileron servos
Misc. Items: Foam rubber padding, medium fuel tubing, fuel filter,
propeller, building and field equipment

SPECS: Wingspan: 56.1" (1425mm)
Flying Weight: 5.5 - 5.9lbs (2500 - 2700g)
Length: 51.97" (1320mm)
Airfoil: Fully-symmetrical, mid wing mount
Center of Gravity: 4.1" (105mm) Back from the wing's leading edge
at the fuselage sides.
Control Throws- Low Rate High Rate
Ailerons: Up & Down 0.31" (8mm) 0.47" (12mm)
Elevator: Up & Down 0.31" (8mm) 0.47" (12mm)
Rudder: Right & Left 1.1" (28mm) 1.6" (40mm)[/size]

Does it still seem like I would need a bigger engine?

Mr48Volts

My Design it sounds like you've got the 40 size....so the engine you have will be fine.

doublesixes

My_Design,
If you're into Yaks, take a look at the Hyperion 40e. It's originally an electric plane but the OS .46AX flies it very nicely. Keep it light and you can do any IMAC stuff you throw at it and even 3D. I just love this little bird and it looks very accurate, if you are into scale looks. I did the conversion by reinforcing and fuel proofing the timber in the nose. I went with standard servos and the plane barely breaks the 2kg mark.

bignuts181

Hi guys I've just gotten back into assambling my yak and will be building it as an electric to fly on the way home from work. At this point I am thinking either an E-flite power 90 or a 110 on 8 cells lipo. So the motors will easily throw a 16x10.

**I have also done away with the servos down the tail in favour of carbon pushrods with the servos mounted in the rudder tray.

**Did anyone else have an unsightly gap around the tail plane??

** lastly what have been everyone elses flying weights??

cheers Rossco

najee

Hi Guys,

Recently got myself the Phoneix Yak 54...My setup as follows

Enging: OS F110A Alpha
Prop : Master Airscrew Clasiic 14x8 (Fun Flying) or APC15x8 pattern
Radio : Futaba 2.4 6 channel radio
Servos : Hitec HS645MG
Batt : Sanyo Eneloop

The plane flies like a charm on low rates and a beast on high rates

Have to thank Spacey for his info on his build that helped me alot on mine...

Spacey

No biggy.

boltor

Just putting together my Yak 54 (63" version) now - one question, the elevator servos are set at different heights in the fuselage - why is that?

najee

Hey Dude,

Congrats on a great plane.. I think its because of the way the servo works. With the diff levels, the push rods will be at the same level on both sides.

BTW guys a note to look into that i discoveed on my YAK. Check the control horns from time to time, mine was a newer version that have abolt running tru the control surfaces and that losen up after a few flites. Balsa vs Metal = metal wins, It could flutter the plane, one of my mates had his fluttering and couldn't find the fault. I changed mine to a DUBRO one which is the same but a better quality so now the aielerons are working fine..(NOTE TO SELF - GET ONE FOR THE ELEVATORS)

The Under carriage is weak too!![&o]

Have fun Boltor

boltor

thanks Najee. What was your experience with getting CG right? I have an OS 91FX and it is tail heavy currently - interested to hear views (just put weight in the nose?) or other ideas. thanks!

vx570

Hi bolter, as reported earlier in this thread: Tail heavy is a problem.
How much weight in the nose do you need to make it balance?
Greg

najee

Actually, the weak undercarriage help with the CG...
While strengthening the undercarriage and ended up with more weight up front and below...
But before that it was slightly tail heavy- just a tinch. I used a Vortex Aluminum Spinner to make it heavier an placed the battery right behind the tank. The PS F110Alpha was about 700gms. So had not much of a prob.

After Mods to Undies batts are now on the wing bar.

Just put my Yak on a scale and it weighs 3850gms without wings...

Now i am thinking of powering it with a 26CC Gasser. Or Get A CMPro Extra 300s 90 size and slam the 26cc gasser..
Nitro getting to be very Ex here. about US$18 per gallon

boltor

looks like I will need about 145g / 5oz up front to balance (with the battery pack right up behind the firewall). Another option I am looking at (probably in conjunction with the weight) is to move the throttle servo up closer behind the fuel tank (might hel[p a bit).

vx570

Another option is to build a box on the firewall and attach the mounts to that.
There fore moving the engine forward, their is lots leeway and room to move the cowl forward also.
Little bit of work but worth it if you can do away with 5oz's of dead weight, wish I had have realised this
when I built mine, might still do it and get rid of that lump of lead.
Cheers Greg

nikon44

where did you get your 63" yak, or where could i get one? i've been looking every where.

vx570

Could be a problem have had mine for about 2 years now, maybe a few shops in Australia,
not sure that they were even available in the US.
Greg

boltor

I bought mine from a shop in Australia too - just saw it and thought it looked ok. Seems like Phoenix haven't really distributed it widely?

Boltor

najee

Well dude if you need one..can get for ya here in singapore...just give me a shout..Was planning to buy another one anyways..

I've got a few lining up on my future shopping spree so i can get one for you if they have stock (very friendly and great planes dont last long in the shops ..lol)

I will be going to the hobby shop over the weekend and see if they have anymore in stock here. should be about 200oz each excluding shipping

NIB items if you want
http://www.hobbyzone.com/rc_planes_s...dge_540_60.htm
http://www.nitroplanes.com/cmpex309065a.html

Happy New Year Mates

boltor

Success! Maidened the Yak-54 this morning and all went well.

Running an OS91 with 15x6 prop. Possibly may alter this prop in coming weeks, but all ok to start off with.

The maiden was the convergence of three 'new' events - first fly of a nitro aircraft (have always flown electric - more on that later!), first fly of the Yak / brand new OS91 of course, and first fly at a real club (always flown at parks).

The flights were uneventful (somewhat boring for onlookers after it became evident that a crash wasn't on the cards!). One click of right trim, one click of up trim and no worries.

Couple of build notes (may or may not be relevant for others)
1) Placed the throttle servo immediately behind the fuel tank (had to construct a small shelf) - aim was to get more weight forward to help CG. Shelf was good to mount the AR7000 Rx as well.
2) Replaced the stock tank with a 16oz DuBro (much better match for the OS91) - this didn't seem to impact flight characteristics as the tank drained.
3) CG was achieved with the addition of approx 150g / 5oz of weight up front - will look for options to remove this (such as Greg's idea to move the engine forward - new mounts or make a small box?). Also, the pilot seems quite heavy so may remove him...
4) Lateral balance was out too, so had to add 10-12g to the left wing - possibly this was not enough to worry about, but not sure
5) Started with recommended control throws, but will increase in subsequent flights
6) Made sure I reinforced main areas with either CA or epoxy - some joints / bulkheads had little glue. The undercarriage held up well to the landings but will further reinforce.

Anyway, very impressed with the aircraft - it's a big jump from smaller electrics (largest flown to date is a 3D FuntanaX, 1100mm wingspan) to something like this, but well worthwhile. The biggest difficulty was landing as I kept overshooting - I found it just floated on and on unlike the electrics I have flown. I did about 6 touch-n-go's before finally landing on the second flight!

Lastly, thanks to Spacey for starting the thread and for everyone else who posted experiences and ideas - very helpful thank you.

cheers,

Boltor