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Mountain Models EVA Bipe

jaredstrees

Well-known member
#21
I was worried about getting CA in the threads but noted for the next build. In this case it was easy to fix, but that might not always be true.

"That might actually be a design feature - one of the ways designers can avoid adding motor thrust angle is to have one side of the wing a little longer, which adds a touch extra drag on that side counter acting the yaw force of the prop wash (at least I think that's the theory behind it). I didn't notice if my EVA has an off center wing, but the Telemaster I built this spring does have an off center wing by design too."

Hmmm. I suppose I'll need to email Brian an MM about it. If anyone else has built the EVA Bipe and has an idea feel free to chime in. I Don't recall seeing anything about this in the instructions.
 

Turbojoe

Active member
#22
I ran into the same issue with the top wing on mine I built 13 years ago. It seems Doug made a small mistake on the cabane attachment point in the top wing. Both are out way too far to attach the cabanes without making them bend. I really don't want to dig through the packed back room right now but I did find an old picture of mine that kinda shows what I did. Look close and you can see the shims I made to go between the cabanes and the wing mounts. If I remember right I used 1/4" per side. The cabanes now stand straight up with no side stress from being pulled way over to seat at the wing mounts. Hope all this makes sense.......

Joe
 

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jaredstrees

Well-known member
#23
That is what I've had to do as well. Seems the outer struts are a bit off as well. Did you need to add any shims to the outside struts?
 

Turbojoe

Active member
#24
That is what I've had to do as well. Seems the outer struts are a bit off as well. Did you need to add any shims to the outside struts?
I actually had to go and dig her out to make sure. Yes, I did use the same size shims on the outers as well.

I can't wait for the move in a few months when the house is built. MUCH more R/C friendly area with a couple of paved runways within minutes of the new house. Maybe finally re-maiden my EVA bipe since I scratch built new tail feathers based on the SwitchBack design. I seriously dislike the 3D tail feathers. Sorry Doug/Brian.....

Sheesh, I still need to finish the EVA trike geared twin. Just can't stop modifying these things. ;)

Joe
 

Turbojoe

Active member
#26
No problem digging her out. It was good to see her again.

Moving about an hour south of Mesa to Florence,AZ. Amazing master planned community. Everything there for old farts like me to 7 year olds like my grandson. Build should be finished Nov/Dec this year. One paved flying field 2.9 miles away. Another 12 miles away. Can't wait!!!

Joe
 

Turbojoe

Active member
#27
Hey, if you're looking for "tail art" the attached picture was posted to R/C Groups many years ago. Wish I could remember who it was to give credit. It's supposed to be sized for the EVA tail.

Joe
 

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jaredstrees

Well-known member
#30
I'd love a few. Not sure I need that much! Thanks again for the help. I hope to get back on this project full speed ahead this weekend. Life has been tricky lately and this little plane is taking longer than I expected!
 

Turbojoe

Active member
#31
I attached a .zip file for you to choose from. There were hundreds of these posted on RC Groups several years back. These are only a few I grabbed for a MM P-51 I was going to build but never got around to.

Joe
 

Attachments

jaredstrees

Well-known member
#33
Made some real progress! I still need to install electronics, paint the cowl, and there are a few small tweaks like shaping the landing gear a bit more and double checking that all the screws are tight. Also need to add a bit more of the striping to the tail feathers. Still debating if I'm going to do a strip down the fuse as well.

EVA1.JPG EVA2.JPG EVA3.JPG

But I can see the end! Well sort off. I'll probably be tweaking this bird a bit even after the maiden!
 

Turbojoe

Active member
#34
Looking good. Just remember for the maiden to keep a little power on when landing. If on final and the prop is stopped it WILL stall and drop! Usually just before touchdown. Really ugly.... Also don't go crazy with a forward CG thinking it's safer. It'll only require a lot of elevator trim or stick input and an increase in the possibility of a tip stall if you get too slow. Go with a mid point CG and quickly you'll be moving it back behind spec to give it a snappier feel without being uncontrollable.

Joe
 

jaredstrees

Well-known member
#35
Thanks for the warning. Now if I could just get some paint mixed for the cowl that matches the dark green solite I'll be happy. And done! Final little items should be handled this weekend, but maiden may be a while. I'll be out of town next weekend. Oh well. Just having her done will be a nice accomplishment!
 

jaredstrees

Well-known member
#36
She is close. All linkages are done. Paint is done. Bolts are all tight. Just a couple stripes left on the tail and a few coats of polycrylic on the cowl. Cowl paint is close, but I could not get it perfect and has been cleaned up since this picture. I hope to maiden her next weekend. Company this weekend so no flying time. I'll snap some beauty shots when she is 100%.


evasemi1.JPG evasemi3.JPG
 

jaredstrees

Well-known member
#38
Thanks! So I have a question. I've never set a biplane up before. Is there an easy way to set the ailerons so they are exact or just break out the ruler and get to measuring? Other than that and the EVA decal that is going on the horizontal stab she's done. I'll get her out for some beauty pics in the sun before she goes for a maiden. May be this weekend, if the wife doesn't have too much scheduled.
doneeva1.JPG doneeva2.JPG
 
#39
I know on the EVA Sport the instructions didn't really say much that I recall about aileron neutral point. The supposed "official" word based on reading the forums was that the ailerons were not supposed to be either flat on the bottom, nor follow the curve of the top of the wing, but be in between the two. In other words if you put a straight edge under the wing and match the aileron to that the aileron will be too high, and if you match it to the top of the wing it would be too low. The recommendation was to put it in between those two extremes. Just looking at the pictures the Bipe appears to have a similar wing shape so I'd guess you'd be looking for a similar setting to start with.