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For building details go to this link that SJN started
http://www.rcuniverse.com/forum/m_21...tm.htm#2162263
Follow his advice on sanding firewall, horiz stab mating surface along with drill dimples for the epoxy to bite into. Then follow your own judgement and building experience to complete the plane.
First off....don't worry about the scary comments about this plane being tail heavy...it's not, that is when using the recommended engine.....I used an OS 1.60 FX with Bisson custom muffler with #1025 silicone extension to exit the cowl. The Bisson Muffler needed a 1/4" spacer to clear the engine mount when I bolted it on....I side mounted my engine. My engine weighs 36 ozs...plus extra for muffler and silicone extension. Prop used APC 18X6W with a 3 1/4" aluminium spinner.

Second.....cut away the servo tray leaving the middle one for the rudder pull-pull. Build another just behind 1/2' higher for elevator. I a used fiberglass pushrod weighing 0.04 oz with 4-40 rod and clevise for elev hookup and 2-56 wire at the servo.

Third.....dremel away around the fuel bottle wood to make space for anti-vibration foam. This is just my personal preferrence. Drill two holes beside the tank in the wood for wire hooks for elastic bands to hold the tank firmly. Note.....The engine mount screws was touching my tank, good thing I noticed it at the building stage...it would have punched a hole in my tank. Solution...cut anti-vib foam to fit over all 4 engine mount screws at fire wall and "Duct-tape" on. Leave a hole for fuel tank leads to exit to engine etc. "Duct tape" same foam in front of fuel tank also....when inserted at firewall, it will be foam against foam. I also put nylon nuts onto engine mount screws. Before inserting tank...place battery pack under tank at firewall wrapped in foam and duct taped.
I used bigger landing gear wheels and didn' t bother to put on that plastic half pant. Xchanged the tail wheel for lighter ones.
Plane balanced exactly at 152mm the recommended CG.
Weight.........11.5 lbs dry
That's it ....follow the rest of SJN's build.

ooooo

GSP only included one side of pull-pull. I emailed them to find out if it was a mistake or is that all they provide. The dorks never responded to me. Their customer service sucks big-time...
Ok....heres pics...

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I routed my antenna in a tube to the right inside of the fuselage and used three 4-40 screws to hold down the canopy.
More pics....

ooooo

Thanks SJN and Volfy if you every view this post for the encouragement to do this build.....I hope my modifications can also help someone else.

One more pic....

fiery

My Feedback: (2)

Hi Kaz

I bought one of these (despite the horror stories) as an "end of year" present to myself. I have spent some time studying the set-up and I have pretty much come to the same conclusions on "build set-up" as yourself. I will use 4-40 links however.

How did the wings go together on yours - no problems?

It is a beautiful kit of a great looking plane. It is not a 3D ship. Their are other kits to accomodate those who wish to try 3D with a YAK.

Thank you for posting your pics! I have downloaded them for guidance. Thanks also to SJN and others who have posted with their experiences - good and bad.

I will build mine as a mid 2005 project. Please post back with flight reports! I think the O.S. 1.60 FX or MVVS 1.60 Glow would be ideal. Only two issues - flight time with the supplied tank, and overheating? Any problems there?

I am toying with the idea of using my MVVS 1.60 gas but do not feel i would be happy with the performance, although I know it would fly it. Maybe an MVVS 2.15 gas, but it may be too heavy. Also, the head would be too high and would demand chopping a hole to accomadate it in the cowl.

Also, canopy attachment - I am thinking of using a dowl at the front and a hobby-lobby "hatch latch" as shown in another thread on the plane. How do you find the screw method?

I think Volfy is using an MDS 1.48 in his. Volfy, if you read this, please post if you have flown yours (maybe you haven't given winter in the Northern Hemisphere).

fiery

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Hi fiery.....forget the horror stories. With an engine in the 36 oz range you will be fine...look at the box cover...it says 2stroke 108 to 160 and for 4 stroke up to 140. I think that is what they mean when the say 140ARF (4Stroke). My plane balanced perfect at 152 mm with the battery under the fuel tank...6v 2000mah NiMh. Just pay attention to the tank against the firewall....if it touches the engine mount screws from inside, it will surely puncture.
I drilled the holes for the aluminium guides....attached the wing with tube and from the inside of the fuse...use a pencil and score the wing where the hole was drilled...both wings at the four locations. Remove wing drill hole to fit alum plugs...reattach wings, ensure the align though the drilled holes. Pull out wing about an inch with the alum plugs still in wing and through drill holes...make sure incidence is still ok. Lean fuselage/wing downwards at about 45 degrees. Use thin CA and wick some where alum plug enters wing...do one wing at a time. Remove and wick more CA into root of alum plugs and that does it. Drill holes for Spring hooks and screw in. Refit wings and turn spring hooks until they enter fuse freely. Those holes are already in fuse..
For Canopy...two sided tape for blue plastic. I don't think that will hold up though, so I'm considering screws, white or yellow car trim to hold down the blue plastic on the canopy bucket. I put two 4-40 screws at the sides up front and one at the rear top to hold down the canopy bucket. I personally think that is enough.
Ok...I only finished building today at 12 noon. Did not fly as yet...have to break in that OS first. I cut a hole for muffler exit..see pic and a circular one over the engine head....those should be enough to take care of the overheating problem. My CG Sukhoi had no holes, just a tiny one for inserting glow ignitor on a Webra Speed 1.20. Never had an overheating problem...never had a hiccup with that engine either.
However.....I'm in Canada and it's winter here..will have to wait for May or June to maiden this plane....I have a Seagull Laser 200 and Velox 1/4 scale to fly before I get to the Yak, but will sure give flight report.
Regarding gas engines with this plane...the OS 1.60 FX is equivalent to a 26cc gasser, but that engine may not have enough power to fly this plane with authority, you may need a 32 cc gasser to swing a 18" prop to fly this plane...but then it may be too heavy.
SJN had success with a Saito 1.80 I believe.....he says it flies like a trainer but until his engine is broken in, he would not put it through it's paces. That thread seems to be dead now though.
If you run into probs with attaching the cowl...let me know and I will post pics of how I did mine.
Cheers.

ooooo

Oh...forgot this...if you need pics of canopy bucket attachment, I will post, if you need measurements of exit holes for elevators and rudder let me know. Keep in mind though the way my servos are setup...see pics. If you set up your servos different...then the measurements won't work. Use autocad or microstation drawing software and draw plane to scale with rudder and elevator linkage and servo location. Join a straight line from servo to control linkages and measure the location for pull-pull and push rod exits. This is a fibreglass fuse...so cutting it up in diff places may not look too good if you don't get the control exits close to accurate as possible. You can also use graph paper and draw the plane to scale 1:1 then measure your exit locations. You can purchase a roll of graph paper at any Stationery Outlet.
Cheers.

fiery

My Feedback: (2)

Hi Kaz

Thanks for the additional tips and info.

I am thinking of springing the green for a 1.60 FX for mine, mounted sideways as is yours, with a BCM pitts muff. I can't stand the thought of chopping a huge hole in that beatiful cowl, and all the install hassles you get when trying to manoeuver the head into it . A coin sized glow driver hole should be all that is required. Is that aerotech tubing on your exhaust? What are the white bands that appear to clamp it to the downpipes? Also, is that a hangar nine adjustable mount for the O.S?

Hmmm ... back to glow ... [&o] - but - the extra power will be welcome .

I am correct in observing that your rudder closed loop cables cross, for a better run to the rudder control horns? Neat.

Where did you scource your elevator control arrowshaft? Is it a brand name R/C accesory? or do I need to make contact with our local archery club I have seen arrowhafts advertised in Tower catalogues and the like, but I have never used them before.

I too will use a Sullivan tail wheel assembly, I fly off grass and the assembly supplied would barely survive the rigours of .32 size ship. I have a Sullivan tail wheel assembly on hand as well....

I am concerned the supplied clunk tank may be too small for 10 minute safe minute flight with a 1.60 glow motor though. Surgery and a larger round style Sullivan tank may be on the cards for mine.

I must start saving for the 1.60 FX []

Cheers

fiery

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hi fiery....OS 1.60FX is the way to go....perfect fit and weight for this plane. My engine mount is metal....I took it from a Seagull Laser 200 that I was building. It gave me an extra 10mm out from the firewall to place the engine. It weighed 1/2 oz heavier than the plastic mount provided by GSP.
I would go with a little bigger opening in the cowl for the glow plug igniter....the airflow would be increased to the engine head for cooling.
Yes....I crossed my pull-pull wires....it fits better in the fuse, and I don't have to cut away the wood forms inside. Make sure the pull pull wire does not touch each other. Use different holes if you use GSP control horns. I used a pull pull .91 size arm. My clevise connectors....I rotated one slightly up and the other slightly down and CA'd in place. I will monitor it to see if it moves..if it does, I will come up with another idea to seperate the wires.
This engine I understand just sips glow fuel.....it sounds like one awesome engine when broken in and has a lot of power using 5% fuel.
I'll use my fuel tank in the beginning and check my flying time. If it needs a bigger tank, I'll change it.
When I get home, I'll check the muffler silicone extension and let you know what brand.
Cheers.

Volfy

My Feedback: (23)

Hi, just checking in to say hello. My Yak is still pretty much as I left it last. Between our 2mo old newborn and 2-1/2yrs old son, building time is scarce and flying time nonexistent.[&o] If it weren't for RCU at least letting me keep in touch with RC, I'd surely go nuts.

I just bought a Mark 2.10 (identical to that other Hungarian "M" brand name) and was toying around with the idea of using it, mostly because of SJN's tail heavy report. But now that Kaz is reporting no lead required with an OS 1.60, I am not so keen on using the big block. I have an MDS 1.48 currently mounted on the Yak. Lat weekend, I ran the MVVS 1.60 glow for my GSP Extra 300 72" on the bench. With the MA 16x8 break-in prop, it pull high 8K rpms still running very rich. Very impressed with the MVVS 1.60 glow and may switch to it if the MDS 1.48 doesn't come close in performance. either case, I will fly it first with an APC 17x8W, and may switch to 18x6 later.

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Hi Volfy....glad you dropped in. Thanks for your input on the thread by SJN.
My plane balanced on the recommended CG....no weight added. I used a metal/alum alloy mount (usual metal mount) that was a bit heavier than the one GSP provided. That combined with the Bisson Muffler + spacer (to clear the engine mount) and the silicone muffler extension may have been the trick to the plane balancing on the 152mm CG. I used the big block they provided. If you noticed from the last pic I posted, there is a noticeable upthrust. This is built into the fuse. One other thing....I used a pull pull for the rudder....no push rod....thus making the tail lighter too. Pull Pull are awesome for these kind of builds.....don't be afraid to use it. Some CA on the clamps and you are good as gold. GSP did not provide enough pull pull wire...and they did not respond to my enquiry.
cheers.

tommydaspad

Hi Guys,

I have this plane and power it with a zdz 40cc gasser and it flys great. I still had to add quite a bit of weight in the cowl toget it to balance comfortably and not be snappy. She will tumble with the best of them with that big rudder it can be quite spectacular. Knife edge tucks to the belly, four point rolls are sweet with very little rudder, elevator input, knife edge spins are pretty good to. Just keep the throws low on the elevator and don't slow her up too much on the landing. Canopy fixing, i used diamond tape on one side for a clear hinge and two hex bolts in to wooden blocks on the other side no problems so far. Undercarrige is crap to flexible and will snap after a hard landing[:@]. All in all i like her but you just gotta be careful on landings or she'll snap.

Have fun

Tom

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Hi tommydaspad.....thanks for the heads up on landings, will keep that in mind. Haven't heard any reports of the fuselage snapping. What is the weight of your ZDZ 40 and what prop?
I think most people built their plane tail heavy. Look at the back of the inside of my fuselage....for the horiz stabilizer...I used the tube, but the aluminium plugs I replaced with light weight spruce. Look at the back of my fuse above the pushrod exit...the spruce can be seen.

>>>Fiery...Where did you scource your elevator control arrowshaft? Is it a brand name R/C accesory? or do I need to make contact with our local archery club I have seen arrowhafts advertised in Tower catalogues and the like, but I have never used them before.<<<<

I didn't use an arrow shaft for pushrod...I did mention fiberglass rods weighing 0.04ozs with 4-40 wire at the elevator control horn end and 2-56 wire at the servo end....
For the muffler extension..I used Aerotrend exhaust stack #1025 with an ID of 1/2" and an OD of 3/4". I held them on with tie-wraps.
Spinner was a 3 1/4 " .... see pics of hardware used.

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fiery....download the pics and use a viewer to zoom in and read the manufacturer's hardware info....the pushrod is Dave Brown Product.
I'm uploading another pic showing "spruce used to glue and hold horiz stab instead of the two aluminium plugs" and the hardwood blindnut/nylon nut combo for holding down canopy....
This is just another method of building this plane.....you can combine this info with SJN and Volfy's info coupled with your experience to put together your plane.

Does anyone have any opinion good or bad of the hardware that I used, please speak up now so that I can change and improve them before my maiden flight. Thanks

Here's the pic....

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Just checked up on the ZDZ 40CC gasser on RC Showcase....it weighs 3.15 lbs with ignition. Not bad...for 4+ hp swinging a 20x10 prop at 7400rpm. Now that's one heavy engine without muffler...hmm and you're still tail heavy. Is your rudder and elevator servos in the tail?
My OS 1.60 weighs 36 ozs....that's 2 lbs 4 ozs..........Bisson muffler + 1/4" spacer + silicone stack extension...lets say another 1 1/2 lbs...then I have 5 lbs +/- in the nose. The APC prop and spinner also adds to the weight......Dunno...but my plane balances of at the recommended CG of 152mm. I am now glad that I built my tail light

tommydaspad

Hi Kaz,

Nope rudder and both elevator servo's are in the stock positions. I see in some of the pics that there is only one pushrod, whereas my kit came with two pushrods for two elevator servo's. My cg is just in between the cg range with the zdz 40 but i did have to add weight to the front of the cowl weird??. I didn't mean the fuz would snap on a hard landing just the undercarrige, although i did mean she would snap/ tipstall if she is slowed up to much on landing..

Don't worry too much but just land her like any other hot aerobatic ship.

P.S i just used all the stock harware with my kit and have had no problems so far.

Have fun

Tom

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I know the diagram shows two servos for elevator...that didn't make sense to me......SJN built his with one servo with a split wire connection like mine.....his flew alright by his account. I will monitor mine as I fly her. I may have to give the pushrod a brace in the middle to stop it from wobbling under pressure in-flight.....I'll use light weight balsa for this hardened with thin CA. Will post pic when completed. Other than that...I'm leaving the plane as is....unless someone can give a suggestion as to which of my installed hardware can fail.
I'm assuming that because I did not install an extra servo and pushrod that my tail was lighter....one oz extra weight at the tail can mean 8 ozs extra weight at the nose to balance.
I thought you meant inflight "snap" if the airspeed was too slow... but when you read the lsentence...it looks like you meant the undercarriage/fuselage snaps on a bad landing. Phewwww.... glad to hear that was not what you meant. Would make for interesting repairs.... leading to fustration...hehe leading to jumping up and down on the plane...haha

cheers

SJN

Hi Kaz. Thanks for the compliments on my build thread :-)

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UR Welcome....... was an informative thread. Just gave it the recognition it deserved.

Cheers.

ooooo

Hey Volfy....is was wondering about that Mark engine. It has a lot of HP and good weight for the plane. Swings a 22X8 prop for 5hp. Weighs 44.5 ozs without muffler. I may just consider one of these engines for another project. Kewl.

Cheers.

Volfy

My Feedback: (23)

Yup, right now, Morris is selling it at $229. Considering what a Moki 2.10 used to sell for, that is just one helluva deal. I haven't checked yet, but I think the only down side to using it on the Yak is that the cyl head will poke out of the cowl. Then again, that might not be bad for cooling purposes.

I know several guys who fly Patty Wagstaff and such (50cc class machines) with the Moki 2.10 with good results. On a 72" 1.20-1.60 class aerobat, it is definitely overpowering. I saw a guy flew a H9 Matt Chapman CAP 232 72" with a Moki 2.10 last weekend and it flew just fine - even with additional lead weight on the firewall. He did say you need to fly it like a CAP, which I take to mean it ain't no floater and you need to keep speed up on turns and on final.

Morris is local here in Houston, and so picking up stuff from him is fairly convenient and saves me shipping charges on big items like ARFs. I have been looking at the KMP 84" Yak 54 that Morris can get. That might be a killer combo.

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Awesome Volfy.....on the KMP 84" + Mark 210 combo. I'll try to get one of those engines from my local hobby shop....he is very resourceful in getting anything for customers. He is one of the best hobby shop owners I know...goes out of the way just to help us modellers.
Did you finish your Yak? If so....let us see the pics.. you can even include your 2 1/2 mth old for beauty touch...haha
Cheers.
Kaz.

SJN

Just bought a new Hemi engine for my Yak!


A MVVS 2.15 35cc Gas engine

SJN

..

ooooo

Nice SJN... how would the weight now affect you? I see you are using a bigger prop....22X8..hmm that plane is going to be a rocket...hehe. Keep us upto date on progress.

Cheers