Mountain Models EVA Sport Build Thread

[rockyboy]

For fun I stitched together video clips of the whole assembly and glue up process for the EVA right wing half. Since it's at 30x speed, that works out to about an hours work in real time to complete it - and another 10 minutes of sanding afterwards to be ready for covering.

I'll switch back to pictures of each step for the fuselage assembly, starting soon!

 

[Turbojoe]

Hey bud, thanks again for the links in post 16. My lead shot and Retro RC fixtures got here today. I knew the neodymium magnets would be better but they are SOOO much better than the crap magnets in my Magic Magnet board package. There are still some really useful clamps/angles in the Magic package but I need to work on somehow converting them to neodymium now.

The lead shot (5 lbs) came in a nice mesh bag. A shame I'll have to cut it open to get to the good stuff. Oh well, ya gotta do what ya gotta do......

Joe

 

[rockyboy]

You're welcome! Very glad to hear they are working good for you - I only bought the 2 pound bag at first and am going to need to get another one as soon as I start on a bigger plane than the EVA

 

[rockyboy]

So after looking at Joe's modification posts about doing hidden servos, I had already decided to cut these servo brackets out and am just waiting on some light ply to come in. But, when I put the ailerons up next to the wings, I also discovered that the pictures in the instructions have the servo brackets misaligned with the control horn slots. If you look closely, the servo bracket needs to be moved over one set of ribs to line up correctly. And I'm pretty sure after double checking the picture in the instruction booklet, that's where the error is. But it was late and I could be wrong.



Time to open up the EVA fuselage kit! Look at all the pretty laser cut parts! Everything is top notch quality - all cuts are precise and go all the way through.



I know the instructions said to hammer in the blind nuts to the plywood, but I didn't want to risk cracking the plywood so I just grabbed a pair of pliers gave a squeeze. Since the plywood thickness matched the nut for these formers, it worked just fine.



Glueing in the first two formers and their associated plywood doublers. This part of the instructions had me scratching my head, rereading, and looking at the pictures very carefully. It all eventually made sense - just have to pay close attention.



And the other angle on those formers and doublers - hopefully this will help anyone else who gets confused at this step about which piece goes on which side of the build.



Time to stick in the rest of the formers. The fit on these pieces is so precise (as they all have been) that I didn't even need to hold them up straight - they stick up themselves, ready for a touch of glue.



The next head scratcher - the fuselage doubler. The fuse doubler is long thin stepped piece with little notches on one side that is in the same sheet as the fuse side. Took me a bit to noodle that out as the pictures weren't very clear on it. But eventually I figured it was the only piece that fit in the former slots left when the side was put on.



Here's the part where the instructions say the wider part of the doubler goes towards the back of the fuselage. It actually sticks up higher than the fuse side back here, and I'm guessing will be used as a lip for attaching the top later in the build.



And putting on side number two - goes much quicker than the first.



And the obligatory down the fuse picture with all the cool lines and angles.

 

[Turbojoe]

You are correct about the wing servo mount picture. They do belong on the other side of the rib for a better alignment with the aileron horn. I just checked all 3 of my sport wings and I have them in the "correct" spot. Must have been something I figured out the hard way on the first one and now just do it from memory. Brian should probably update the manual. When I do the hidden servos I'll mount them and the horns mid wing to hopefully reduce flex of those thin ailerons. As I've posted before with a strong motor I get aileron flutter at high speed but only with the sport wings.

Joe

 

[rockyboy]

Thanks for the tip - I'll center the control horn up in the aileron and let that guide the placement of everything else.

 

[rockyboy]

Servo tray installed here. Per Joe's suggestion, I added little strips of 1/32" plywood where the servo's will screw in for extra hold.



Control rod tubes installed here. Although they stick out different amounts on the tray end, they are both level on the back.



And here's a close up of how much room I left for the control rod tubes at the exit points. First time I've used these, so I hope this will be a good distance.



Next is the T bracket that goes along the top of the rear turtle deck.



And here are the two pieces that make up each side of the rear turtle deck.



First glue only the bottom edge of the turtle deck sides to the fuse.



Then pull out your handy spray bottle of ammonia. Works better than water - very fast acting and penetrates way better. If you don't trust me on this tip, take it from Crash Hancock - I did.



After wetting just the outside surface of the turtle deck and waiting less than a minute, it became very flexible along the grain and with a little bit of painters tape it's now becoming curved.



While the turtle deck panel dried, I moved ahead a step to put the reinforcements in where the wings mount. To make sure everything stayed in alignment, I ran the carbon fiber tube through the big hole, and a slice of bamboo skewer through the little hole at the other end. Then clamp, add a dab of glue away from all the temporary stuff, and let it dry. Then pull the clamps and alignment rods out and finish gluing on the reinforcement.

Everything lines up, and nothing extra is glued in place. Ask me how I learned to do this process in multiple steps... :black_eyed:



Adding the brace on the back of the firewall.



And attaching firewall to the fuselage. Once the firewall is in place, the little triangle reinforcements are cut to length and added.



At this point the first turtle deck side is mostly dried out and the other side is ready to be glued on at the bottom. This is probably 2 hours later - I had dinner and a family movie break between some steps here.



And finally the second turtle deck half is sprayed with ammonia - being careful not to get anything else wet - and then taped over in place. I might have been able to do both sides at the same time, but this way works well too.



Now it's time to let the ammonia dry out overnight before gluing the turtle deck in place.

 

[rockyboy]

And after 24 hours of drying the balsa holds the new curved shape nicely.

So time to trim a little off the top of the turtle deck pieces so they don't hit each other (it all gets sanded flat in the next step), drip in a little medium CA on the two inside formers, tape it down, and then run some thin CA around the edges.

That's all I've got time for tonight.

 

[Joker 53150]

Your documentation of the build is A+ material, nicely done! It's what I wanted to do with my build, but was too lazy to do.

It's going to start looking a LOT like an airplane fuselage very soon...!

 

[Turbojoe]

I have to give a thumbs up as well. Exceptional documentation. Everything is framed well and that nice blue background makes it so easy to see everything. Like Joker, I'm just way too lazy (and unskilled with a camera) to produce build shots like that. The last full on build thread I did was on the MM Tom-E-Boy 150. Loved building the plane but hated all the time it took to document everything. Props to you for the time you spent. Thanks for sharing.

Joe

 

[rockyboy]

Thanks guys! I'm having a lot of fun with both the build and the documentation - it's forcing me to slow down and really think through the steps, which is good - sometimes I can get a little impatient and miss details.

The blue background is purely a happy accident - the metal shelf came with that blue plastic film as a scratch guard during shipping, and I just haven't bothered peeling it away. It is acquiring some nicks and gouges, and won't last forever - but hopefully through the end of this build.

 

[Turbojoe]

Joker has done a lot of great build threads so to get recognition from him is an honor!

Joe

 

[rockyboy]

Thanks guys!

I hope everyone still feels that way when we get to the covering. :black_eyed:


Just a little bit of progress tonight - just a busy time of year.

Did a quick shaving and sanding of the top edges of the turtle deck to create a flat surface with the top of the T plate. Then glued on the top plate, and taped it in place as I didn't feel like grabbing the kicker.



And then attached the four rear turtle deck pieces on the back.



After I did this, I realized the instructions said to sand the top plate of the turtle deck smooth first - but too late, it's already glued in place. So tomorrow when I do the main shaving and sanding of the fuse, I'll let you know if the way I did it turns into a pain in the butt.

 

[Joker 53150]

You can save yourself a lot of dust by carving much of the tail block before sanding it.

 

[rockyboy]

Definitely my plan. I even have some micro sized planes (wood shaving ones) around here somewhere I used for smoothing guitar necks that should work great for this.

Just need to figure out where I put them...

 

[Joker 53150]

Even whittling some excess away before sanding would be better than only sanding. A razor plane makes VERY fast work of it.

 

[rockyboy]

Even whittling some excess away before sanding would be better than only sanding. A razor plane makes VERY fast work of it.

Why yes, yes it did.

First step after I found the plane was to rough in the shape of the 4 blocks glued onto the very tail end of the craft, while leaving the tape on the flat plate to make sure I didn't start cutting into that yet.



Next I took off the tape and roughed in the rounded shape down the entire top of the turtle deck.



And then out came the 'sanding beam' for final shaping. My weapon of choice here is a strip of 320 grit sandpaper taped on the bottom of a metal level. Works pretty well to keep long straight lines from developing curves. Some day I'll get a roll of 320 sandpaper so I can run the paper the entire length of the level, but so far I'm doing ok using the standard sheets from the local hardware store.

 

[rockyboy]

A few stolen moments in the shop today, and a little quick work with the razor plane and sanding beam shaped the bottom corners of the fuse to match the cowling. I did put a little balsa filler in there to smooth over a rough gap where the plywood and triangle balsa didn't meet all the way - my placement issue earlier, but easy enough to fix.



If I was going with the stock tail dragger configuration this is when I'd glue the tail wheel reinforcement to the bottom of the fuse. However since I'm planning on a tricycle landing gear (sick of nose over's in the rough grass at the local field) I'll be skipping this step.



And the final bit on the fuse for today, and for this section of the instructions, is to glue in the magnet shelf for the battery tray.



Next up are the vertical and horizontal stabilizers - some to get out some hold down clamps!

 

[rockyboy]

Over the last couple days I stole away for a couple hours when everyone else was napping to make some more progress.

First up is the rudder. The puzzle fits together very neatly.



Then the vertical stabilizer and one of the elevator halves.



Now the horizontal stabilizer and the other elevator half.



I should have been putting down waxed paper to prevent the CA from sticking things down to the table, but it wasn't too bad until I started pulling this one off. Lost a little balsa on this one, requiring some filling to put things right again.



Now on to the canopy base.



And I missed a picture. There is a strip about 3/4" wide that goes across the two curved braces and provides a flat place for the sheeting to glue onto (which is what you see here, weighted down with the bottle of glue for a moment).



And finally with the assistance of a little ammonia the edges of the sheeting are taped down into the curve and left to dry overnight.



Next up will be finishing the canopy base, and starting some modifications - flat mount servo's and the tricycle landing gear!

 

[Turbojoe]

You're gettin' there! Looks good.

I finally did a little work on mine today. Got one wing mod almost done. Finished mounting up the nacelle and slapped together the hidden aileron servo framing. It looks OK from the outside. The inside, not so much, but it's functional and strong. Hopefully I can get the other wing done tomorrow.

Joe