Mountain Models EVA Sport Build Thread

[Turbojoe]

Looks amazing! I wish I could think up cool covering schemes like that. Because of the high temps here in Arizona covering has to be tightened once in a while. With large overlays I worry about uneven shrinkage and bubbles. Maybe I should go ahead and give it a try sometime and find out if my fears are well founded....

Joe

 

[Joker 53150]

Very nice work on the covering!

 

[rockyboy]

Thanks guys!

I hope I don't run into problems with the overlay either Joe - If I planned ahead more, I suppose I could have cut all the strips ahead of time from Solite, joined them together on the glass work surface, and then attached them to the wing so it would all be a single layer of covering. But I still have a little too much drift when attaching covering I think - need to work on my tacking technique a bit more.

No more progress on this one tonight - spent the time getting my quads ready for the race tomorrow morning. With luck, I won't be second to last this time.

 

[SlingShot]

That looks really nice! That's the Antique right? That color scheme without stripes is on the cover of the B-25 XL brochure

I ordered the bipe today. The price has gone up. The covering choices were kinda sparse. I went with Lux Blue for the wings and Black for the fuse. Maybe a little wing trim. I've seen that color combo look nice on a bass jig.

 

[rockyboy]

Thanks! Yep - that's Antique Cream and Black - I forget which old timer design I saw this color combo on - maybe a Daddy-O or parasol design on RCG - but I think it's pretty classy. You can also get the same covering under the same AeroLite from https://www.stevensaero.com/ - between MM and SA they usually have different colors in stock.

 

[rockyboy]

Progress!!

So I attempted to do the penguin on the other side of the rudder with Solartrim pressure adhesive material rather than Solite covering. Had more trouble getting a clean cut on this material, and couldn't salvage the lettering. I think with more practice the Solite method might give better results.


And here's where I notice my next mistake. Yep - didn't prepare for the servo wiring to go through the extra distance to the new flush mount location.


So time to find some wire to extend the servo leads and a thin tube that the wires will fit through.


Soldering on an extension to the servo lead - not going to have room to leave a standard connection in here..


Turning the tube into a long hollow drill with a file...


Carefully drilling through each of the ribs between the square servo lead hole and the new flush mount servo location. Just wiggling it with my fingers worked fine - no need for drills here.


Now pushing a thread through the tube with a little ball of tape and a wire.


And wrapping the wire around the servo lead pins - when they are popped out of the connector, the three of them will just barely fit into the tube.


Keeping pressure on the thread so the servo lead doesn't get lost, gently pull the aluminum tube back out.


Perfect! Now repeat for the other wing.


Next was a fitting of the motor and cowling. Turns out the canopy was too long - rather than cut it down, I stuck in some plastic stand offs between the motor mount and the firewall to bring it out to the right place. If this messes with my CG too much, I can always remove them and cut the cowling down.


Looks like a good fit now!


And with a little epoxy on the horizontal and vertical stabilizers to mount them permanently, I'll let this all sit for a few hours.

 

[rockyboy]

Dealing with another set of unintended consequences....

So when adding a layer of plywood where the servo mounting screws will go, don't forget this moves the servos up in the fuselage. Need to move the control rod guide tubes up by at least that same amount. If you don't move the tubes up, you'll end up like I did using a linkage adapter upside down on the control horn.

How did I get that in there? It wasn't easy.


Glued in the control horns on the tail surfaces. The back end of the plane is all wrapped up.


I'm getting to a fairly short punch out list here!

• Install aileron control rods
• Check esc/motor rotation
• Mount esc
• Servo for front wheel
• Install cowling
• Install battery strap on tray
• Install receiver
• Install magnet in hatch
• Balance
• Program radio & servo throws
• Fly!

 

[jsknockoff]

So close!!

 

[rockyboy]

Done

• Install aileron control rods - check!

To Do

• Check esc/motor rotation
• Mount esc
• Servo for front wheel
• Install cowling
• Install battery strap on tray
• Install receiver
• Install magnet in hatch
• Balance
• Program radio & servo throws
• Fly!

 

[Joker 53150]

I'm really liking the look of your plane, and the mods you did to it. Nothing crazy, just good practical updates.

 

[rockyboy]

Thanks! Appreciate the encouragement from everyone!

The only part left that's going to be fiddely is mounting the servo for the front wheel. This is the first plane I've done ground steering on since 1989

With the extended motor mount and nose steering stuff, I'm expecting she'll want to sit nose heavy. I hope I can get a good balance just by shifting the battery back - and maybe using an 1800mah instead of a 2200.

 

[rockyboy]

Joe, where did you mount your servo for the nose wheel? Or did you just run an extra control rod sleeve back to the rudder servo?

Thanks,

 

[Turbojoe]

Joe, where did you mount your servo for the nose wheel? Or did you just run an extra control rod sleeve back to the rudder servo?

Thanks,

I pulled off the rudder servo with a cable. I should have done a cleaner job but I was just throwing pieces on there to see what would work. It wasn't pretty but it worked so I just left it. There's enough room down below that an extra servo in the forward fuse would work just fine. The extra weight isn't an issue in this bird and I'm sure the CG could be maintained with a minor battery adjustment. I'll probably try that on the unfinished trike geared twin EVA if I ever get back to it.

Joe

 

[rockyboy]

Thanks for the pics Joe! I went with the servo right up front, and it's a good thing too. Need all the forward weight to make balance I can get. Right now unless the battery is in place and moved a good bit forward, she sits back on her tail. I hope I got the landing gear moved far enough back... looking at your pictures I think your location is about 1.5" further back than mine. Simple enough to fix if I need to - just build a longer extension plate. Once I do final balance I'll have a better idea if I need to do this.

I used some of the spare balsa parts from the normal wing servo mounting setup to hold the nose gear servo.


Here's the electronics layout inside. I needed to carve a little bit out of the battery tray to deal with the nose servo too.


Hmm... landing gear looks a little funny here. Needs straightening.


And the cowling is in place now. Looks pretty. :applause:






Getting closer!!

• Adjust main landing gear angle and mount wheels
• Install battery strap on tray
• Install magnet in hatch
• Balance
• Program radio & servo throws
• Fly!

 

[Turbojoe]

Lookin' good!

Maybe it's just the angle of the photo but it looks like your mains are considerably further forward than mine are. Mine are about 1 1/2" behind the C.G. Still forward enough that I can use the elevator to ride on the mains after landing if I want but rearward enough that it stays planted. There were no calculations involved to arrive at that location. TLAR and just plain dumb luck.

Joe

 

[rockyboy]

She flies!!! :applause:

I moved the landing gear per your suggestion Joe, and it worked like a charm. She was the 4th of 4 planes doing maiden flights on Saturday morning and the ground was punishing. @Wilmracer's P-40 had the right gear break lose, and his T-38 broke an axle on taxi testing. Then my EasyStick pancaked about 10' after takeoff and tore it's landing gear plate right out of the fuselage. So I was a little nervous when it was the EVA Sport's turn on the runway.

But, she is so light she handled the rough ground just fine on thin 3" wheels. Took off in about 15 feet into a steady 8-10mph wind and climbed straight for the clouds! She is so lightweight I had to fight the wind a lot - especially her climbing tendency. But she flew pretty much where I pointed her with only a little waggling - next flight I'm going to try putting the CG about 1/2" further forward from the stock recommendation. Stall behavior was very predictable and straight forward - no sign of a wing tip dipping.

I had a more of an orientation challenge that I expected - the black from the top of the wing casts a shadow through the light cream color. I might add a wide white stripe on the bottom of a wing tip to help out.

I was a bundle of nerves when it came to landing. The wind was straight down the runway, but still causing her to pitch up and around a bit. With a little luck I was able to set her down softly on all three wheels at once, and she barely rolled out 10 feet before coming to a stop. :applause:

Flight video coming soon, and additional flight reports from a hopefully less windy day in the future.

Bottom line - lovely build, lovely flyer - highly recommended!

 

[ranger351]

Awesome report! Great to hear she's a good flyer. Sorry to hear about the other troubles.

 

[Joker 53150]

Congrats! That reminds me that mine really only needs a few hours to bundle everything up so it can fly. I'll have to get working on it soon!

 

[Turbojoe]

Congrats on the maiden! Looking forward to the video.

There's a lot of wing area and not much weight so she'll get tossed around when the wind blows. I hate flying in the wind but when I do I usually use an 1800-2200mah pack to fatten her up a bit. With your nose gear and servo up front I would expect you to have to move the battery back just a bit rather than forward. Do you maybe have the ailerons drooped a bit causing the climb?

Joe

 

[rockyboy]

Thanks everyone!

Joe, I'll have to take a look at the ailerons again - thanks!