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Build along thread Mountain Models EVA "MODS"

Turbojoe

Well-known member
#21
I also have a nice scar in my leg from a rolling table knife. Really messes up a pair of jeans to bleed all over them like that. So another way to stop holes in Joe - put a zip tie on the Xacto handle and snip off the tail. Slide it around so it's out of the way of your hand, and then when you set it down it can only roll a little bit.

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Way back in the old days I used to drill and tap for a 4-40 bolt. No roll and it made it handy to hang in peg board. Comes in handy when you have a bunch of handles with different blades. I never thought to do it again after getting back in after my 20 year lay off while I was married. The zip ties work great too.

Joe
 

Turbojoe

Well-known member
#22
I'm thinking about shelving the twin conversion for a little while. It's becoming more frustrating than fun. The build is a piece of cake and all the components are pretty much done. It's providing passage through the wing for the wiring that's driving me nuts. I usually use 1/2" rocket tubes but they're too big for this wing. I've made the biggest hole I feel comfortable with using sharpened 13/32" brass tube. Now I need to find lightweight tubing that will fit. I may spend some time in a craft store looking for something that might work. I tried rolling up craft paper but I inverted a bunch of new cuss words during that fiasco. Once I get the wiring done to where I'm satisfied then it's all downhill from there.

Joe
 

rockyboy

Skill Collector
Mentor
#23
Way back in the old days I used to drill and tap for a 4-40 bolt. No roll and it made it handy to hang in peg board.
That's a very cool idea - I've been using a plywood stand with holes and tossing them in point down into soft foam , but a nice hanging solution has merits.
 

rockyboy

Skill Collector
Mentor
#24
And recommendations on the placement of the main gear in the trike scenario? I'm finding some chatter that making it an equal distance back from the CG as the CG is from the leading edge is a good place to start.

But I'd rather put the blind nuts in once and be right rather than move them all over the place. :)

Thanks!
 

Turbojoe

Well-known member
#25
And recommendations on the placement of the main gear in the trike scenario? I'm finding some chatter that making it an equal distance back from the CG as the CG is from the leading edge is a good place to start.

But I'd rather put the blind nuts in once and be right rather than move them all over the place. :)

Thanks!
My trike main gear position is 50mm back from the cg. The same distance to the conventional main gear position. I don't remember for certain the criteria I used to determine placement. I think I may have measured one of my MM Tyro's and gauged it from there. More than likely it was just a wild ass guess that happened to work for me. ;)

Joe
 

Turbojoe

Well-known member
#26
Well I've actually made a bunch of progress on the twin. I finished up both nacelles and hidden servo installation. Mounted up the motors and just said screw using tubes to run the wiring through. I think I can keep it tight enough through the ribs that it won't lay on the covering. I mounted both assembled wings to the fuse for the first time and it looked great! That is until I looked at it from the side. I made a fatal error with the motor thrust line. Not sure how but when I installed the firewalls it looks like I put them in with well over 5+ degrees of down thrust. I could shim the motors (maybe) to compensate but then the face of the nacelles will be at a weird angle to the spinners. I've done some stupid things before but this one takes the cake. I obviously wasn't thinking when I added the firewalls. Once I saw it I had to just hang my head in shame and walk away from it. I'll take another look tonight and see if I can somehow save the nacelles. I really don't want to have to build a new set. I should just put it away and finish up some of the other half finished projects.

I've been looking at the Telemaster 40 in the corner that just needs the wings joined and final sanding. It's been sitting in that state for 6-8 years now. Maybe finish wiring up my MM Tyro 150 done up as an attack aircraft with bombs, missiles and machine guns with LED's and sound. I stopped working on it when all the FAA/drone stuff flared up. It may not be a good idea to fly it even now. It does look like something that SHOULD be shot down. :eek:

Joe
 

rockyboy

Skill Collector
Mentor
#27
Sorry to hear about the nacelle mix up. I've done a couple bone headed things like that myself, and often just sleeping on the problem for a day or two will cause the solution to bubble to the surface. For a recent example, I'll show everyone my solution to screwing up the landing gear mounting locations on my EVA in a day or two. :)
 

Turbojoe

Well-known member
#28
Two days now. Every time I look at the twin setup I'm infuriated with myself for doing something so stupid! The twin is officially on the back burner now. I'll get back to it eventually. I already have two EVA's ready to fly and all the wings. It's not a problem if this one doesn't fly anytime soon.

I've got quite a few unfinished projects. I just did an inventory and it looks like the ParkScaleModels Monocoupe 90 is closest to completion. Mine is covered in the same black/red scheme as the one on the website. I built the flap/aileron wing for her. Looks like all the electronics are in her and all I need to do is install the windows, wing struts, wheels and wheel pants. I stopped on it probably 5 years ago so my completion list is likely WAY off base. I'll find out this weekend.

Joe
 
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Turbojoe

Well-known member
#29
Can't believe it has been 8 months already since I stopped on the EVA Twin. I pulled the wings/nacelles out yesterday and it looks like all is not really lost after my stupid nacelle screwup. I made some motor shims and it looks like I have the thrust angles pretty darned close now. At least close enough that it should fly good enough to determine what further adjustments if any might be needed without crashing. I keep looking at those 3D tail feathers and I just can't leave them. I'll make SwitchBack tail feathers for this one like I did for the EVA Bipe. I may eventually tear the 3D's off the first EVA Trike and put SwitchBacks on it too. I MUCH prefer the rounded SwitchBack look. Also working on another crazy mod. Hoping I can do it successfully. It'll be way cool if I can make them come out the way I want.

Hoping the work phone won't ring all weekend for just once and I can make a little more progress.....

Joe
 

Turbojoe

Well-known member
#30
Been pretty quiet around here lately. Everyone is probably out there flying. Still too bloody hot here for me. Early to mid October and I'll be out there again. I keep plugging away at the EVA twin. Added some balsa sheet to the front of the nacelles and sanded to match the new motor thrust angle. Looks pretty good now. I'll be running Scorpion 2212-22 motors. I looked at the prop chart and went with the APC 7x5E to try to keep watts and amps down. I just ran up a single motor with a 3S 2200 pack that is at storage charge and got 119 watts @ 10.2 amps! With a fully charged pack I'll probably get at least that and likely more from each motor. Over 200 watts! Way too much power but I can always use the left stick to keep the speed down. My ESC's jump from 10 amp to 25 amp and up. Nothing in between. I just ordered a couple of 20 amp ESC's from H.U.R.C. Should be here Friday. I've already made up all the harnesses so as soon as the ESC's get here I can finish the harness ends to the ESC's for good clean installed length. I made some changes to the wings. 100% for looks. They'll likely have little affect on flight performance but that wasn't my goal anyway. I'm almost at the point where I can start covering. I'm still not 100% certain which way I'll go. I have three ideas in my head. I guess I'll find out what it will end up as once I get started....Joe
 

rockyboy

Skill Collector
Mentor
#31
Very glad to hear she's coming along nicely. Any thoughts on adding some extra bracing - carbon or balsa - to the control surfaces to help with the possibility of flapping at high speeds?

Would love to see some pics of how you're doing the nacelle mounting and all too - I have an EVA Bipe kit to get to eventually, and making a twin engine bipe out of an EVA would be a little different. :)
 

Turbojoe

Well-known member
#32
I could have sworn I posted some pictures of the twin conversion. I guess not. I'll try to take some shots tonight.

I am planning to beef up the ailerons a bit. I have some 2.5mm carbon fiber rod on the way from Heads Up R/C. I plan to add it to the trailing edge. That along with the control horn being in the middle of the aileron I hope will stiffen it and help with the high speed flutter I've seen on my Sport versions.

An EVA Bipe twin would be way cool! It's not a hard mod if you don't get stoopid like I did and not pay attention to firewall thrust angles. :confused: Still kicking myself for that one.......

Joe
 

Turbojoe

Well-known member
#33
OK. I took some pictures. Hopefully will give an idea of what was going on in my warped little mind. I've made several nacelles based on the design from the Gemini Twin from plans drawn by Al Eastman of Eastwind designs. I've built three Geminis from his plans. Sadly his website is gone and even sadder is that I can't find out what happened to him. I want to buy more of his plans! When I go at projects like this everything becomes a prototype. Therefore it may not look perfect and there may be a gap or two here and there. If it works it works and that's what I go with. I'm not going to build another part just to make it pretty in areas you can't see.Everything I did is really pretty basic. I may be able to scan the nacelle from the Gemini plans if you want a starting point. I'm just throwing the pictures out here. Any questions? Ask away!Joe
 

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