Building the Yak 54 - 79"
 

Well guys and girls I will try to take pictures of the kit construction as I go along be patient I work a lot of hours at my job so it wont be an overnight construction job but I am meticulous and very detail oriented....

Here are the first few photos this is the construction of the balsa fuse skin, you use pieces of 3" by 42" sheeting to make a single sheet then it goes on the foam fuse core...

Before you can laminate the sheeting to the fuse you have to install the servo doublers, wing rod reinforcements, and the hatch (battery and reciever) hold down doublers to do this you need to cut out some foam so they sit flush with the edge of the foam surface..

RE: Building the Yak 54 - 79"
 

I do have a few questions for Mike about the engine mount installation it is not very clear to me which pieces of wood to use and how to instal them, if they are instaled before of after the sheeting on the fuse, thanks...

RE: Building the Yak 54 - 79"
 

Going to move this one to the main profile forum. Thanks for posting, however we are trying to keep the OMP forum open for tech support stuff.

Looking forward to your build!

RE: Building the Yak 54 - 79"
 

OK after re-reading the instruction a few times I figured out that the motor mount is installed after the fuse sheeting is done. So here is the fuse being sheeted, I sanded the fuse lightly to be sure the glue adheres well, with gorilla glue you have to wet the material on one side put the glue on the other then weight the project with heavy weights, I used four 50 lb boxes of tile to flatten it out nicely...

RE: Building the Yak 54 - 79"
 

Here are a few steps I did that were not in the directions I put some string in the servo tunnels so when I install the servos it will be super simple to get the wires through to the reciever, the other thing I did was to put some ply doublers for the throttle servo, it probably isnt needed but it makes me more secure...

RE: Building the Yak 54 - 79"
 

I wish I had put strings in my 80" edge, believe me it is worth the effort. [:@]:eek:

RE: Building the Yak 54 - 79"
 

1fish, great job so far. Glad you figured out the engine rails. I'm usually flying or building on the weekends so I don't turn the computer on unless I'm flying my AFP sim! You did pin that sheeting in place before weighting it down didn't you? That glue is really powerful and can slide the sheeting off unless it's anchored. Also I always use wax paper and a large flat board in between the sheeting and the weights to help distribute the weight and keep anything from sticking. I've learned sometime that Gorilla glue penetrates a small hole or maybe you got a finger pring on the outside and wham! you've glued it to your board! Hopefully yours turned out great.

As far as string that's a good way to do it. I've always used a piece of 48" nyrod as it's stiff enough to go through but flexible enough to bend where you need it. Works extremely well. You may have glued in that string?

RE: Building the Yak 54 - 79"
 

Well no I didnt pin down the sheeting but using 200+ lbs worked out fine, using the wax paper would have been a good idea I did get one little "glue through" but it was of no consequence, I used a sharp putty knife to separate the sheeting from the tile box with no damage, as for the strings I hope I didnt glue them in but i dont know yet, I have used Gorilla glue before and am pretty good at getting the right amount on the project so it dosent squeeze out though the edges and hopefully the tunnels...here are a few pictures of me cutting the outline shape

RE: Building the Yak 54 - 79"
 

Here is a few pictures of me capping the fuse edges, I cut a few groves in the wood to help it bend easier, but I found i need to steam it to get a good contour with out breaking the balsa....

RE: Building the Yak 54 - 79"
 

Here are the motor mounts I shaved the rear block a little too much so I had to shim it a little looks like crap but it should be fine, I put a few small slices in the balsa shims on the upper and lower mount so it would hold more glue, once I laminate the doubler it wont show any way....

RE: Building the Yak 54 - 79"
 

The pic in post #2, Is that the battery area just under the motor mount area? I have the kit waiting it's turn in line. I just finished up the 65" Yak about 4 weeks ago.
Matt

RE: Building the Yak 54 - 79"
 

This picture shows the battery hatch reinforcement, later when the hatch is attatched it will be used to put the hold down screws in..

RE: Building the Yak 54 - 79"
 

Sweet, i was just thinking of getting one of these kits! Keep up the pics, look forward to the finished product.

BTW, what are you going to power it with? I have a NIB 1.60FX that has been sitting for over a year now, but i dont know if it is enough to tourqe it.

David

RE: Building the Yak 54 - 79"
 

The OS 1.60 IS the most desired engine for this plane. All the personal OMP planes use the OS 1.60 with mousse can pipe. The performance is unlimited.

RE: Building the Yak 54 - 79"
 

Great to see this build. I have the 65" Yak I am flying - love it - I also have an os 160 at home that needs a place to hang!

How much more time does this take to build than the 65"?

It looks like not much foam left in that battery area of the fuse! Is this "the weak spot"?

Scott B

RE: Building the Yak 54 - 79"
 

David I am using the YS 140 DZ (supercharged and fuel injected) shoud be more than enough power/torque for this little unit!!! There are lots of people using the OS 160 its a great engine for this size plane, you will be very happy..



Scott, I dont think it would take much more time to build at all, its only a little larger, for me most of my time is spent getting ready and cleaning up after working, I dont think the battery area would be a weak spot at all, its kind of framed in by the solid hardwood motor mounts and cap strips on the bottom of the fuse and the plywood doubler on either side, should be more than strong enough...

RE: Building the Yak 54 - 79"
 

Yea, I forgot about those ply doublers, that should do it just fine. Keep building!!

RE: Building the Yak 54 - 79"
 

Just getting in a little construction on the plane before I go to work, I had a hard time lining the blueprints up with the holes to be cut so I just found the center made a small hole so I could see then I cut out the hatches and other openings...
The last two pictures show installing the hardwood blocks for attaching the landing gear

RE: Building the Yak 54 - 79"
 

How many times have you had to mix epoxy so far? Keep count - on my 65" I think it was more than a dozen times!!

I used Micro balloons in the epoxy , It makes it easyer to fill and easyer to sand! I did not think it would weaken the epoxy enough to worry about.
AFSalmon what do you think?

RE: Building the Yak 54 - 79"
 

I have only mixed epoxy a few times (engine mounts, landing gear blocks, plywood inserts for servos), because I am also using Gorilla glue (in any wood/foam contact) during the construction but when I get to wing and the wing tube I am sure there will be many more times!!!
Micro balloons do weaken the glue somewhat but if used as filler it doesn't make much difference to the overall strength of the air-frame..

RE: Building the Yak 54 - 79"
 

Scott, I still don't understand why you mix so much epoxy? The only thing I use epoxy for is to glue the engine rails in place and this is done with one batch. Everything else is done with Gorilla glue or Probond. The microballons should never be necessary but a small amount should not affect the bonding strength.

RE: Building the Yak 54 - 79"
 

I did use Gorilla Glue to put the sheeting on the foam and the the 1/4" around the Fuse but I used 5 min. for all the thru fuse blocks. I had to mix a batch almost every time I put something in. I wanted to be able to quickly go on to the next step and Five min. w/ micro-b seemed the quickest way. Using more gorillaglue would have cut down on this for sure but I think the directions said epoxy.

1.engine rails
2.landing gear blocks
3.wing hold down
4.battery door screw blocks
5.throttle servo blocks
6.horz stab
7.vert stab?

that is Just the ones I remember now on the fuse
The wings took at least 4 more mixes
Triangle corner braces right &L
Dowel insert from root into leading edge Right &L
that is 11 without seeing the plane or directions I know if you do a word search in your directions you will find more.

BTW I am not complaining, as you know I love my Yak and it was easy to build. I just never had to mix so much.

Fish--I will try to leave you alone now -- get building!!

RE: Building the Yak 54 - 79"
 

Hi, sorry this is off topic, but how thick is the blue foam in one of theese fuses?

This is why...........

http://www.rcuniverse.com/forum/upfi...50/Zx71486.jpg

I doubt it'll ever be built, but im designing it anyways. I got the idea for it when i found in teh back of a mates car when sheltering from rain a bit of 3/8" blue foam and CF sheeting either side. weighed next to nothing and was amazingly strong. he said he could make me a bit (possibly 1/2 inch thick blue foam) with the CF.

Ill let you guess the plane, im hopeing it looks something near scale.... the tail is been drawen up now, and the wing will take me quite a bit of time.

so if anyone can tell me the thickness of the OMP foam fuses.........??? and after that back on topic.....

Thanks
Ian

RE: Building the Yak 54 - 79"
 

My OMP 65" Yak was about 3/4", maybe 7/8". Whatever the foam comes in standard sheet size close to that. Sukhoi maybe?
Matt

RE: Building the Yak 54 - 79"
 

OK after a 75 hour work week I finally got a day to do a little work on my plane, in the pictures below I have finished casing the fuse around the nose, drawing in the center line, and then I am adding the wing dowel (where you screw down the rear of the wing), so far it has been a pretty simple straight forward construction.