Mountain Models EVA Bipe Kit

[Doozer]

www.mountainmodels.com/product_info.php?products_id=214

Since its starting to warm up here (getting close to 90F), and I tend to not fly when it starts hitting the 100's, I decided that I would build a small kit. If this turns out to be successful, meaning that I love it, I plan on building a larger Ultimate from a kit. This Plane is electric, and small. The size was the key feature that fact that it's a Biplane was icing on the cake. I wanted something I could build on my table, and when I stepped back, I could see the bigger picture, so to speak. 

This plane is called the EVA (Extremely Versatile Aircraft) because it is a modular design. It is, or can be, three different planes if you purchase the other wing kits. I purchased the Biplane wing kit and the 3D wing kit.  I haven't decided on a motor yet, but I plan on taking my time, so I'm not in a hurry to make that decision. 

Specifications:

Wingspan: 31"
Wing Area: 446 sq in
Length: 32 in
Weight: 16 oz without battery
Wing Loading: 6.1 - 6.5 oz/sq ft
Channels: 5 (Aileron x 2, Elevator, Rudder, Motor)

Kit Contents:

Laser cut wood
Lightweight Aluminum Landing Gear
Wheels
Pushrods and Housings
Servo Connectors
Misc. hardware

Tools Needed:

Sharp knife (#11 X-Acto)
Sealing Iron for covering
Sandpaper
Screwdrivers
Needle Nose Pliers

Items Needed to Complete:

2 Rolls SoLite (Covering)
Thin and Thick CA
4+ Ch Radio
4 Servos (GWS Picos, HS 55, or similar)
4+ Ch Receiver
Y-Connector (If your TX does not have 2 aileron servo mixing)

Minimum Power (Not 3D Capable):

GWS EPS350c-C
9.6V 650 KAN NiMH Battery

Recommended Power:

100+ Watt Brushless Motor (Geared stick-mount or Outrunner
3S 1500 MAh LiPo

[akphill]

Looks good I like building from laser cut kits myself
But a suggestion when doing wings like those save yourself some heart ache and use a wing jig to build them it will help a whole lot in getting them straight

Here one of these
www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXK258

[Doozer]

Mar 17, 2014 11:00:59 GMT -6 akphill said:

Looks good I like building from laser cut kits myself
But a suggestion when doing wings like those save yourself some heart ache and use a wing jig to build them it will help a whole lot in getting them straight

Here one of these
www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXK258

Purchased! Tower Hobbies owes you. Thanks for the input.

[akphill]

Welcome

[19000rpm]

Going old school on us eh, Doozer. That's great!

The last kit I built was 7 yrs ago. It is a balsa stick and tissue P-38 by Guillows that I built as a static display. It took me about a year to build. I really enjoyed the process and it brought back a lot of good memories of building kits with my dad; back in the day when if you didn't build you didn't fly.

Great tip on the wing jig Phil. There's nothing worse than building up a wing and having it come out warped.

[akphill]

Yep I have and use it myself
After I built a cub and the wings were to warped to straighten
Darn old work bench was warped and built them to it lol

[19000rpm]

I bet you 90% of us did that at least once.

[Doozer]

Mar 18, 2014 14:43:21 GMT -6 19000rpm said:

I bet you 90% of us did that at least once.

I'm hoping I don't have this problem. I've been surrounding myself with tools lately,and that looked like one I could use for sure.

[Doozer]

Haven't got very far. I've been pretty busy. Got a Sony Action Cam and experimented with taking some pictures.


Laser cut wood. 

[Doozer]

worked on it a little more today.


Sheets that they came from


Could have used thick CA here, but I went with 5 min epoxy instead. These sit right over top of the landing gear mount, so I thought a little "sturdier" glue might be in order. The directions say you can use either.




Once the CA dried, I removed the landing gear mount then mixed up some 12 minute epoxy and put a thin layer on the bottom. The reflection of the of the light makes it look like there's a lot, but if you look closely, you can see some dry spots. I'm really trying to keep the weight down. 


Clamping it down for a solid bond


This is the sheet that they came from



Tacking them in with THIN CA. 


Dry Fitting the Fuselage sides


This is what the Fuse sides look like. Notice I've got wax paper covering the mat so I don't get glue on it. 


This is one of the two 1/16th Ply Fuselage side doublers. Figuring out what piece they wanted to me a little time since there aren't any "plans" in the traditional sense. More like the instructions you'd find in an ARF, but they don't label the pieces like you'd find in a plastic model. some of the wood had come loose, so I have some loose pieces laying around. I finally got it all sorted out and dry fit these doublers in. 


The instructions say to make sure that the "Fat" part of this double faces the rear. Those notches should line up with the bulkheads. Then you glue them in. The instructions say to fit both fuse sides in then tack them with some thin CA and then glue the doublers in. I went one fuse side at a time, and I think this was easier. The fuse side had notches cut out to fit the tabs on the bulkheads, so dry fitting is a snap (no pun intended). You just need to be very careful because this is balsa and those tabs are easy to break...ask me how I know.






Using thin CA I glued the triangle stock to the fuse sides and bottom. 

The next two pictures are all the steps, completed, that I've highlighted so far. This is where I stopped for the day, maybe longer. 



to be continued....

[akphill]

Cool starting to take shape
which is looking good too

[Doozer]

Worked a little more on the EVA yesterday. Here's some more images and a couple of short videos. I have a few questions I'll ask at the end:


Installed the servo tray... It's important to note that while "dryfitting" adds time, it's absolutely crucial in most situations. It gives you a chance to find mistakes or obstacles before there is turning back. 





Installing the tail pushrod guides. These are the smallest pushrod guides I've ever seen. I had to use needle nose to install them. 



That's the hole for the guides... maybe a 1mm 1.5mm wide. Doing it by hand was like trying to thread a hair through a hole with link sausages. 


So far, mountain models has really left no stone unturned. The holes go though every bulkhead all the way to the tail. I'm really enjoying this kit. 


You can barely see it in this image, but the pushrod guide (yellow) barely extends past the slot (upper).

<img style="max-width:100%;" src="http://planetdoozer.com/images/EVA%20Bipe/DSC00299.JPG" alt=""><br>Installing the turtledeck "T." As you can see, the "T" fits in pre-cut slots in the top of the bulkheads.


The 1/32 doublers go here so the turtledeck sides are flush with the fuselage sides.


Turtledeck side


This is where the turtledeck sides go.

This is a video of how to install the turtledeck side:




This is what the side should look like before sanding

This is a video of how I sanded the turtledeck sides:




After I finished sanding






Wing Spar reinforcements.


Glued in (above two images)




Attaching the front crutch to the firewall


The crutch can be found on this sheet



Dryfit, then glue it in. 


Slide the the 5mm piece of triangle stock through the triangle shaped gap between the front crutch and the firewall.

Watch this video regarding the installation of the triangle stock. Useful tip:




Find the four rear turtledeck blocks and glue them together, then glue them to the top of the tail just behind the turtledeck.




Important... Do NOT glue those ends together. You'll need to leave them open to fit the Vstab in. 


Sand the turtle deck blocks round


Install the canopy magnet tray



I've actually gone a little further than this, just haven't uploaded the images yet... I do have a few questions...

I've built the Vstab, Hstab, elevators and rudder. The manual calls for tape hinges. The stock is not big enough to even slot for CA hinges. Is there another hinge, better than tape, that I could use? Bearing in mind that I can't drill or slot. If I do use tape, I plan on using "Blenderm" (medical tape). Is there a configuration that someone suggests that I use? 

Thanks guys... TBC!

[19000rpm]

If you have to use tape; Blenderm or hockey tape are good because they are tough and also stretch. What are you going to use as the exterior finish?

[Doozer]

Mar 30, 2014 15:45:03 GMT -6 19000rpm said:

If you have to use tape; Blenderm or hockey tape are good because they are tough and also stretch. What are you going to use as the exterior finish?

I have two rolls of black Solite, then I'm going to airbrush. And I hear you when you say "If you have to use tape." I just don't know of any other alternative. The smallest hinges I've seen would require slotting, but there's not enough wood for that. The stock on the LE or TE of any of the stabs or the control surfaces is 3mm. And I double beveled the rudder and elevators.

[19000rpm]

I'd think the small dubro pin hinges would work. secure.hobbyzone.com/DUB118.html You can either insert them, or if you'd like, mitre them into the surfaces and fill over. There's nothing wrong with tape except it is more visible. I've got some taped hinges that have lasted for years.