Spacey

Good day everyone!

Been a while since I started a new thread on a plane so I'm a little out of practise but ok here goes. I figured I'll put this in the 3D forum as I need help choosing a motor for this model to get a good power to weight yet light wingloading combination. Those who knows me will know I have a fairly decent fleet of 3D profiles flying and well I've been in the market for something fat again for quite a while as I wanted something to have fun with and also draw a straighter line across the sky with to practise my precision skills a little. The profiles I have just don't cut it and are just frustrating to say the least when it comes more patternish aerobatics. So yea I still aim to one day save up and get something big like a H9 260 with a DA50 but at the moment other priorities made that idea impossible. Friday afternoon I stumble into the LHS (Yes it's my home away from home) and BAM this sucker just can't stop begging me to take it home. It was a kind of "Love at first sight" thing. Got it for a really good deal and it also retails here for $216, who can resist at that price?

Now ok in all fairness I'll never get my hopes for it to 3D well if at all as previous experience already taught me that smaller fatties just don't do it but ok I'm still going to build it with the mindset that it might.

So here's the deal thus far. It's a 63" wingspan model so a nice and comfy size. Covered fully in Oracover (Didn't triple check but sure looks like the stuff). All laser cut construction with extreme lightning techniques used all over the place like holes in the leading edge sheeting blah blah so the idea is right barring it stays in one piece upstairs. What some would call airfoiled tail feathers (Dunno it's a funny one to describe but yes it is sorta airfoiled..lol). Carbon fibre pushrod kits already included in the kit for all the surfaces except rudder which is pull-pull. Overall I can't say ANYTHING bad about the quality of the plane thus far and bare in mind I hate ARFS for the quality issues they had in the past with covering etc. But from what I've seen till now on this thing I have to ask how in the world they build these things for this price?!?!

Ok so last night I unpacked everything and started weighing all the components to try and figure out a AUW so I can choose the right motor. I added everything I could possible think of including 6X40gram servos, switch, leads, reciever, epoxy (I hope I added too much), a very heavy battery (Yes with the idea to save weight later on that), prop, stickers everything and got to 2950grams WITHOUT motor. That's about 6.46lbs for everything except motor/exhaust and fuel. Now which motor to choose?

Terribly sorry for the long post. Hopefully it was interesting enough to read. I decided to blurt it all out since I couldn't find anything through the search on rcu on the plane.

tIANci

Spacey - looks like you will be touching 8.5-9 lbs by the time everything is in. Do you want to really 3D or just enjoy her? If 3D then you will want something like the Saito 100 as a mere minimum. You can look into the SA125 also or the new OS120 2C. For me I would plug in my YS110!

Spacey

Hi tIANci,

Yes well at the moment I will be putting it together to actually see if it can 3D or not to some extent so power is a must but I'm not too worried about ballistic. I'm not that good a 3D pilot so I don't trash around. I can manage with a little less as I usually collect myself between manuvers anyways.

I've got my list narrowed down a wee bit already since the top post. I can either use my Super Tigre .90 I already have but I'm worried it'll be barely enough to hold a hover at my 4300feet above. The ST .90 3D's the poop out of my 6.1lbs TMPro Katana V2 and hovers that at less than half throttle on a 15X4W but how much power is still left on top of that to 3D a 8lbs plane I worry about. The OS 1.20 AX will fly the snot out of this Yak for sure and price seems okish...but alas it's heavy. Saito 1.25 is the lightest of the bunch I got in mind but the price scares me and will it have enough power?!? I also have access to a OS .91 which I can get for a really good deal if not for free. I have to add I have a really nice throttle/muscle pipe for the .90 2-strokes which does add about 500rpm to normal specs.

The weights I found of all the motors:
Super Tigre .90 w/muffler: 27oz (765grams)
OS .91 w/muffler: 24.3oz (688grams)
OS 1.20 AX w/muffler: 31.4oz (892grams)
Saito 1.25: 24.7oz (700grams)

Sorry although I really want to try a YS I'd just much rather go for the Saito 1.25 as YS isn't available here by us and the 30% nitro thing doesn't freak me out. Dunno Saito just looks like a much better investment in terms of ease of use.

Edit: Sorry just noticed a booboo on the weight conversions. Fixed.

Texan

My Feedback: (10)

Spacey,

What rpm are you getting with the ST 90 on the pipe? I have a ST 90 that I'm setting up for 3D with the following:

Powermaster 10%
APC 14x4W
OS 7D carb
Ultrathrust muffler

Max rpm 12,700 (head temp 280)*
Min rpm 1,500

* I can run FAI 0% nitro and get 12,500 with head temp @ 250 but the transition is not as good. I will try 5% soon.

tIANci

Spacey - I would not go with the ST90 for an 8 lbs plane. I used it on my Harrier 3D 90, its hovering at like 80% throttle. I am sure the SA125 would be a great choice. I love YS engines but like you said ... they like high nitro content.

Spacey

Hia Texan,
Sorry I haven't had a chance to tack my motor with the pipe on as I don't own a tachometer myself but the "Add 500 odd rpm" statement was motivated as a very reliable source/friend of mine did check hes and put me onto this pipe I'm using now. I'm not going to make any promises on when but I am going to try for this weekend to borrow a tach and check it out for you.

Spacey

Agreed..It would just be too risky to bother with a .90 2-stroke on this one. I see the guys are using the Saito 1.25 on things like the Showtime which is also 8lbs+ with good success so I suppose it'll be a good match for this plane too. I have never owned a 4-stroke other than a Super Custom .80 4S in a Anniversay Cub around '96. Back in those days the four strokes were so underpowered compared to now that I really can't put my mind at ease yet if the 1.25 is even going to be enough. But yes the weight numbers put the Saito way up top as far as great choice goes now I just got to convince myself it'll have enough grunt. I spoke to the LHS owner for a LOOOONG time last night about my choices and he also talked me into a Saito. He is the only other person in my club that can 3D with the best of them and we kinda sung the same tune on the matter. So ya it looks like it'll be the 1.25. I'm going to sell another model to help fund the Saito as it's by far the most expensive motor I ever considered buying.

Got any suggestions for props and such for the Saito? Before we start figuring out what servos to use!

Texan

My Feedback: (10)

The Saito 1.25 should be a great choice. I like the looks of the Phoenix Yak. Good luck with your project.

BTW, my ST90 is going in a AW Edge 540 60"... hopefully under 7lbs.

tIANci

Spacey - I believe that the Saito 125 will swing a 16x6 or 15x8. This link is good:

http://www.saito-engines.info/

Spacey

Texan: Thanks for the encouragement! I got some emails from old friends also confirming that the Saito is the best choice of the bunch with this plane and future models in mind. Good luck to you with that AW. We don't get the AW models here in ZA so I've never seen one with my own eyes. Stick around on this thread if you like. I'll more than probably post some pictures of the build when I get going on it.

tIANci: Thanks a bunch mate! I checked out the site and yes those prop sizes makes sense. I hope my LHS has those sizes or can get them for me. I suppose I'll have to try both the 16X6 and 15X8 to really see what this Yak prefers. When talking those kinds of prop number I also assume it's just normal blade APC props right and not wide blade props? Sorry you don't need to answer that but just thought I'd ask cause maybe you know.

Texan

My Feedback: (10)

Spacey,

I have a friend interested in the Phoenix Yak, however, can't locate a kit in the US. Is the Yak a new release from Phoenix Mfg.? Perhaps they have not arrived here yet.

Spacey

Hi Texan,

Yes this one is made by the same company that makes the Fun Star's and all the .40 size fun-scale aerobats. Well ok they make quite a variety of things. I see Tower is a US agent for them and has some of their models in stock along with quite a list of spare parts like wings and canopies whatever you need.

[link=http://www2.towerhobbies.com/cgi-bin/WTI0096p?&N=P&C=&S=4802398&P=7&F=PMMA5132&L=PMMA5122&S1=PHOENIX&S2=MODEL&S3=MFG&S4=]Phoenix at Tower[/link]

Unfortunately it seems us poor South Africans are playing labs rats again on this model too. I've noticed we get alot of models quite some time before they hit the states. I don't know which other countries also get them before hand but maybe their using our market for a test bench?
So yea let me help your friend out rather and let me do the testing on this sucker since I've already got it. It shouldn't be forever before I rig it up as I'll probably pick the motor this afternoon (My poor credit card). I just have some other small projects and jobs to do before I can put this on the bench. I'll probably start late next week.

vx570

Hi Spacey.

How is the building of the YAK going?, have just purchased one, was traveling in QLD Australia and wandered into a hobby shop and there is was, couldn't believe my eyes a Phoenix Yak 54, never seen one before, anyway haven't had a close look yet but on first glance looks good, like you not to sure of the power yet, like the 4 stroke idea looks like the 125 is the go, will do away with the crook looking wheels and replace with Robart's, the canopy looks as if it needs finishing off, interested in how yours balances and flys, anyway cheers from OZ.

Greg

Spacey

Hi Greg,

Lately I've been having some serious headaches commiting to projects as my eggbeaters are really taking priority and you know how often they break something. I am going to try my best to get something done soon but I have to finish off rebuilding my primary F3C machine. The heli is very nearly ready to go as I just need to get the reciever in and do the final setup so hopefully I can make time soon to tackle the Yak. You have no idea how badly I want to put this aeroplane together but time just doesn't allow. [:@]

I also won myself a Seagull Harrier .46 over the weekend so there's even more fun projects at home waiting to see some action. LOL. I really do hope to get going on the Yak this week as I now have everything lined up and ready. But I will definitely post some pictures and comments as I go along with this one.

vx570

Also have a couple of projects to go before I start the Yak, just one of those kits I couldn't resist when I spotted it in the hobby shop, still not sure about the engine choice as yet.
Also have a 46 Seagull Harrier, have a shot of it in my Gallery, was having trouble seeing its direction at times so added some colour to the wings etc, much better now, power is Mag 52 4 however little under power could have used a 60 4, still heaps for an ole bloke like me.
Cheers Greg

Spacey

Hi Greg,

Love the picture of the kangaroo in the gallary..too cute! I noticed first thing as I took the Harrier out that orientation was going to be a hickup that needs adressing. I will have to do something to get a good view of things if I ever intend to fly some normal aerobatics with it and not just close in 3D. I like what you did with yours..very simple and I can imagine effective too. I have to admit I am very worried about the powerplant for the Harrier. See I fly 4300ASL and sometimes even more at the neighbouring cities like I mentioned above so I can't skimp on motor. And yes then there's the same problem with wingloading at my altitude so not much room to make the right decision in. I see the guys on the forums say they build theirs to around 2.6kg AUW and that's way too much for a .46 or even .50 2-stroke here by me. So i'll probably have to look at something like a Saito .82 or .91. But I'll worry about that at a later stage (Funding is depleted right now ).

Things are looking up for the Yak and if nothing comes up to waste or take up more of my time I might be lucky enough to start building on it this week still. Hold thumbs for me? hehehe

vx570

The kangaroo is great except he is now over 5ft tall and a bit of a handfull, still living with the family that took him in after his mother will killed, by a car I think.
Bit to big now to bring to the field.

Have ordered a GMS 76 2 stroke for the Yak, they seem to have good review's in the "user review section" so will give one a go, also 539 JR servos and one of the new RS77S Synth receivers, also will update and add a better pilot and a little detail in the cockpit, 2 3/4" Robart wheels and a 3" alloy spinner, [cant help myself!] should look the part.
Wallabies in the Trynation Sat, will be watching.
Greg

Spacey

Hahaha..they grow up so quickly?

I see the guys on the local listings are praising the GMS motors too. Price seems right so they will open up a slot in the market. I think the .76 should pull this plane around quite nicely. Not sure what it'll do for the motor 3D wise but it just might have the power to sustain a hover if that airframe is up to the task. I am finishing up my Sylphide tonight as all that's left to do is set up the pitch/throttle curves which is a quick task. So yea if I can convince myself to stay out of the pub tonight (It's Friday?!?) I will start building the Yak. I am going out on a limb(sp?) here but going to say that I WILL have build pictures up in the thread on Monday morning.

Spacey

Right on assembly is under way! I had another commitment to get to last night and only got home around 8pm so I didn't get quite as much done as I would have liked to but thus far I'm having a lot of fun. I haven't built an ARF in what seems like years so it is quite a fun experience again. I took a whole bunch of pictures of everything and yes the pictures are pretty self explaining so saves me some typing. If anyone has any questions please ask.

Couple of notes for inexperienced builders tackling this one: Make sure you have a high grade locktite handy to locktite all the little nuts and things in place. I fly eggbeaters so I had some "Superstud" grade locktite handy. I am also going to add a tiny drop of CA to everything after the final setup is finished. Also take your time with the setup of the horns to make sure you get the geometry nice and 90degrees to avoid roll differential problems later.

Also remember to roughen/skuff the carbon pushrods slightly before using CA to glue them into the connectors. I found that the connectors were drilled a little too small for the carbon and opted to sand the carbon rod to fit. Probably not the best idea but I am more than happy with the amount of rod left and the two in one making fit/skuffing job. Also be sure to use plenty of thin fresh CA to glue the pushrods in place. Only thin CA will wick into the connector nicely and make sure things are locked into place. Oh and be carefull in this step not to get any glue on the covering. Rather shove a piece of cloth in underneath the pushrod assembly for the first spill of CA and make sure that a drop of CA that goes on a road trip doesn't glue the cloth to the covering. You will also have to remove the pushrod assembly after you first glued it to get the length right to zap the under side with CA. Easy peasy stuff though.

Wings are done! [8D]

Spacey

Last two.

vx570

Notice you have long servo arms on your 539's, little frustrating with the JR 539 servos with the short supplied arms, have ordered several pkts of Dubro long arms, I think JR should supply them with the upgraded BB 539's.
Greg

Spacey

Hi Greg,

Yes those are the JR Super horns. I use them on all my 3D models. We buy them here in the LHS in packets of four for about $5 or so. You also get them in horn variety packs from JR along with the big servo wheels and things. They work well and does give a nice 3D geometry setup on the .40-1.60 sized models. The 539's have a generous amount of slop in the gears as is so I do everything I can to minimize slop to the surface.

Cheers
Spacey

vx570

Bit of a warning, dont know how you are going to set up your elevators, but I purchased a SJ electronics Y Lead Servo Reverser, made in Korea for my Great planes Extra 300 these things seem new to the market so you may have them over there, the come in a red and black pack, well this so called reverser worked about 5 times then sent the servos into a frenzy, then failed to work at all, just imagine if this had happened in flight over a $1000 worth of aircraft without control, was going to get one for the Yak, but they can keep them.
Cheers
Greg

Spacey

Hi Greg,

Hah thanks for the warning. Never been much of a fan of the SJ stuff. We get their motors here but I haven't seen the Y-lead thing you speak of. Fortunately I will have the luxury of plugging the extra elevator servo into a spare rx channel and using my 9X to link things up. I'm going to be using a 7-channel reciever on this one so it's going to be an easy setup. Or so I hope at least.

Spacey

Progress update: Right so I forgot yesterday was a public holiday here by us and yes that means Tuesday night had a fair share of beer and good friends involved while the whole of yesterday was spent practising for the F3C. I did manage to make some more time last night to fiddle on the Yak and got the tail feathers all glued in. Unfortunately I forgot my memory stick at home so the pictures aren't here for upload but ok more to share tomorrow. I think I may have found my first problem with the plane as my rudder is a little warped. Hopefully working the covering a little will fix it. More tomoz!