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Build along thread Mountain Models EVA "MODS"

Turbojoe

Well-known member
#1
A quick disclaimer: Not a single Mountain Models kit requires ANY modifications to fly great! Some mods are done for looks. Some are done for "perceived" performance advantages. Then there are those mods that I do that make no sense whatsoever other than to bastardize a perfectly good kit into something that pleases me personally. :D

I'm really not sure I've ever built any kit without at least minor modifications. The quality of Mountain Models kits give me a near perfect (for me) foundation to personalize to my particular tastes. I won't bore you with the many unnecessary mods I've done to other Mountain Models kits.

I love this build off! It started off centered around the MM EVA series but some are going with other kits and that's the beauty of this. All that matters is that people are getting back to the roots of the hobby. The fun of building with balsa and telling others that I built this! No bARF's. No foam. All good times!

Several people are doing exceptional documentation of their builds. I won't be doing that. In fact all I'll be posting is modifications that I'll be doing to the poor undeserving EVA kit. Some I've already done before and some I'm working on. The trike gear mod was easy and very successful. I'll be posting up what I did to make it happen. Hopefully others will post up what they think I should have done differently. Everyone benefits from that criticism and I don't have any feelings (just ask my ex-wife) so you can't hurt 'em.

My EVA Trike gear Twin....That's in progress. Trike gear mod is uber easy. Twin not so much. I'm working with a set of poorly built wings I bought a long time ago and rebuilt. If I ever get a chance to finish the fuse I'll find out if I can actually salvage those crappy wings. If not I have a new set I just got from Brian. Motor nacelles are built and ready to install.

It's the wrong time of year for me to expect to have much free time. Work right now mandates I don't get ANY free time. I'll put in time on the build as I can get it. I encourage all to post up any mods they've done or wish had been differently in the kit that would make it easier for future builders.

Joe
 

Turbojoe

Well-known member
#3
OK so here's my first mod of many. I always use at least .047 music wire for control surfaces. Just a pet peeve of mine. This necessitates a larger guide tube so I use the inner 1/8" yellow tube from Sullivan Gold-N-Rod. I have piles of the stuff. The .047 glides effortlessly in that tube but you have to drill the fuse former cable openings to 1/8". I also open and elongate the rear fuse pushrod opening to 1/8" wide and from 1 inch long to 1 1/2" long to minimize drag caused by angle change. In the other picture attached I don't like running servo screws into balsa even after "hardening" it with thin CA. I use a piece of 1/32 ply glued to the top of the mount plate just for grins.

Joe
 

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Turbojoe

Well-known member
#5
Next up is the trike gear mod. This was soooooo easy! There is so much room not unlike the cramped nose of the SwitchBack trike mod that nearly drove me straight into an asylum! I've never been a fan of conventional landing gear and I just love trikes. Hence my dislike for all warbirds other than the P-39. (I FINALLY scored a H.O.B. P-39 kit a year or so ago!)

I don't have a lot of pictures of the trike mod because it progressed so fast and easy but if you want to do it and need more shots just let me know and I can shoot them from the original mod. The original mod probably has 50+ flights on it and is rock solid. When I get the time I'll be doing the exact same mod to this build. The ONLY issue with the trike mod is that nobody sells a 1/8" nose gear package anymore so I used the Dubro #234 1/2a 3/32" nose gear package but I bent up my own longer 1/8" gear and drilled the nose gear bearing to accept it. I did it only because of the rough area I was going to be flying at. After looking at the stock Dubro gear wire it may be a little short after bending for the wheel axle. Maybe the main gear could be splayed out to compensate? In any case the main gear MUST be moved back from stock location when doing the twin mod and a new internal plate made with "T" nuts for mounting. Easy.....

I'm pretty far along with the twin motor mod but those poorly built wings I bought are giving me fits. I should just burn them and build new but I refuse to admit defeat. The nacelles are done and ready to go. Once I finish the fuse I'll know if the twin mod is even possible with these thin wings. I won't complete the twin mod if providing a path for the wiring will compromise wing integrity beyond a safe flying aircraft.

Also, the only mod that I see as necessary on the EVA is the main gear plate. The gear per instructions is mounted to the balsa fuse structure that will collapse and loosen the main gear with use. I add a 1/8" plate between the main gear and the fuse balsa regardless of where I've mounted the main gear. I just can't think of anything else that needs any attention on the EVA though.

Joe
 

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Turbojoe

Well-known member
#6
I like these ideas! Glad I'm reading this before I start my fuse or close up the wings :)
If I can make the twin mod work on the Sport wing I'll be doing hidden aileron servos as a necessity for clearance reasons. Will be an easy mod even on a completed wing. I'll post up the mod as I get to it. Will probably add 8 or 9 grams each side but EVA won't care. I've flown her with a HEAVY 3S 2200mah pack and a 100 watt motor with Bipe wings and was still happy with performance! A truly amazing kit.

The EVA wing design was never meant to handle landing loads or I would have already done retracts a long time ago.

I'm at work again and only have access to the files on my thumb drive at the moment. Looking forward to getting home and actually working on the build for a few minutes until that freaking phone rings again!!!@#%:mad: :mad: :mad:

Joe
 

rockyboy

Skill Collector
Mentor
#7
Hmm... hidden aileron servos... that would be a very nice touch. Yep - not covering up the wings until after I see those pics. :)
 

Turbojoe

Well-known member
#8
Hmm... hidden aileron servos... that would be a very nice touch. Yep - not covering up the wings until after I see those pics. :)
I haven't started on the EVA wing servos yet so I went looking through pictures of my other planes. I'm horrible at documenting my build progress and usually only shoot the final product. No good pictures of hidden servo build except one. No big deal. Just take an airplane apart for pictures. I grabbed the closest one. A scratch built Goldberg Eaglet 50. Now THIS plane is modified! All balsa build. The original kit was used only for templates. Not a single part from the kit was used. Electrified. Lowered dihedral. Removed all wing and horizontal stab incidence. Two access hatches on the bottom. Bolt on wing. The list goes on. Love this plane! You can see in the pictures that the hidden servos are really easy to do. It'll add a few grams of weight but it'll look better and be at least 37.3 mph faster due to the lower drag. ;) Hope the pics help.

Joe
 

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rockyboy

Skill Collector
Mentor
#9
Oooooo..... love the hidden servo look! Easy maintenance access, and seems pretty straightforward to build too.

I'm going to need to get some basswood, 1/32, & 1/16 ply cause I'm going hacking! :applause:
 

Turbojoe

Well-known member
#10
Tools?

Hey, how about some "tools". First pic is of a piece of scrap 1/16" ply from the EVA kit. MM parts tolerances are really "gnats ass". That's really good and you can usually dry fit major assemblies with no glue. Sometimes the tabs and slots can give you a little grief though if you need to assemble and reassemble many times while you are modifying. Especially 1/16" slots. I take a piece of scrap ply and work it through the slots and wiggle a bit in the fuse side slots to make it easier to trial fit everything together before I take it all apart again. :confused: Works great for me.

Second is something that may raise some eyebrows. Hypodermic syringes. :eek: I don't know what the laws are in every state but here in Arizona you can buy 'em at any pharmacy. And that's WITH needles!! (we can carry guns too :eek:) They're really cheap as well. I'm moving steadily away from CA glues and just love Super-Phatic. It's already thin enough to use in the syringe but I'm sure you could thin aliphatic glues like Titebond enough to use in a syringe. The 3ml syringe with a 1.5'' needle makes it so easy to put just the right amount of glue in exactly the right place even at the bottom of a fuselage or far reaches of a wing bay. If there is still glue left in the syringe sometimes I squirt the excess back into the bottle and rinse the syringe. Sometimes I leave the glue and fill the needle cover with 91% rubbing alcohol and let it sit for next use. (water will make the needle rust).

Joe
 

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Snowblind

Propeller Balancer
#11
I love the syringe full of glue! Cant say how much I've wasted cleaning the bottle tip with a napkin so I could get a tiny amount somewhere. I've even used the tips of zipties and toothpicks to get spots that need very little glue.

If you ever find the need for them medically, I would recommend finding a better source for needles. If they rust in water especially over a short period, then they are not made of surgical stainless, and might not even be suitable for bodily use.. Marinade injectors don't rust, yet they get stabbed into dead turkeys/etc.
 

Turbojoe

Well-known member
#12
If you ever find the need for them medically, I would recommend finding a better source for needles. If they rust in water especially over a short period, then they are not made of surgical stainless
Thinking back, the one that rusted was a blunt tip from an ink jet cartridge refill kit. That needle was probably made from an old finishing nail........

Joe
 

Turbojoe

Well-known member
#14
One alternative EVA tail

In the R/C hobby there are only three things I'm not a fan of. That's 3D planes and their ugly squared off control surfaces, WWII warbirds (except the P-39!) and DRONES :mad:. That said I just had to make some changes to the tail surfaces on the EVA. I know she flys just fine as mine did for years on my original EVA but I hacked those feathers off and grafted some modified SwitchBack feathers on to her. (SwitchBack owners will notice I added some cross bracing to the horizontal surfaces) Because I did this while the Bipe wings were mounted I also decided to scratch build a much larger version of the SB rudder to maintain rudder authority. I think it came out OK. After hacking the old feathers out the only mod necessary to the fuse was filling in some of the horizontal stab slot and adding a bit to the end of the fuse to take it out to meet the new rudder. This mod was SO much easier than I expected.

Brian is going to drive all the way down to Arizona just to kick my ass for this but when I get around to building my replacement Lucky Ace it will have rounded tail feathers. :black_eyed:

Joe
 

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Turbojoe

Well-known member
#15
And another alternative EVA tail

OK. This tail is what's going on the EVA Trike Twin if I ever finish it. Nothing terribly special. It's still the stock tail feathers with counter balance areas but I simply rounded everything off. Nothing more than personal preference. No mods to the airframe. Just a minute or two with the sanding block and it makes me happy and I haven't even sanded the parts "clean" yet.

One mod I always make is to use carbon fiber tube everywhere I can. In this case I used some 3x2x1000mm CF square tube I recently got from HeadsUpRC for the elevator joiner. LOVE this as it has much more contact area than round tube or wooden dowel. There will be NO chance of flex!

Joe
 

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rockyboy

Skill Collector
Mentor
#16
I certainly like the rounded look on the tail pieces - but I also like the covering simplicity of sharp corners :)

Also, like that mod to 'Bill's Fingers' magnetic hold downs - need to do that to my own to make them easier to pick up and move around.
 

Snowblind

Propeller Balancer
#17
Turbo, put some shoes on when you're at the build table, I don't want to read that you've dropped your hobby knife in an unfortunate way!

It's usually considered truth that sharp points and corners are aerodynamically irresponsible. There are lots of exceptions, but I like the rounded look you have going; As well as the way your scratch-building mimics the laser cutting so well.


Spoiler!

Sorry about the rant.
 
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Turbojoe

Well-known member
#18
Turbo, put some shoes on when you're at the build table, I don't want to read that you've dropped your hobby knife in an unfortunate way!
I learned that lesson a long time ago. Now I sit when I build. No more Xacto's in the foot. Now they get stuck in my leg. Buried a #11 to the handle several months ago when I tried to grab one rolling off the table. If I had just let it go it probably would have missed me. I ended up stabbing myself! :eek: Now I lay a yardstick between the table and a full length power strip mounted to the edge. No more holes in Joe!

On the rant.....My dislike of warbirds has nothing to do with the aircraft themselves. It stems from the hobby doing maybe a dozen or so to death for SO many years. You just get sick of seeing the same old thing ad nauseum. Kind of like how many Cubs are on the market. A great plane but I'm sick of them. I still can't figure out how I ended up with 5 of them.

I was seriously considering building a drone/tri/quad before everything blew up with the FAA and the few morons that damaged the hobby for everyone. That's a discussion for another thread in a different forum and will just become pollution here.

Joe
 

Snowblind

Propeller Balancer
#19
I get what you mean, seeing everyone saturate the market in more of the same, gliders for example, some have 4 or more names mashed together, (That old Sky-Cloud-FloaterJet or w/e it was called) yet, it's just another soaring plane, with the same wing as the last.

Gotta get a kit to occupy me, one-line posts keep growing longer on me.
 
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rockyboy

Skill Collector
Mentor
#20
I learned that lesson a long time ago. Now I sit when I build. No more Xacto's in the foot. Now they get stuck in my leg. Buried a #11 to the handle several months ago when I tried to grab one rolling off the table. If I had just let it go it probably would have missed me. I ended up stabbing myself! :eek: Now I lay a yardstick between the table and a full length power strip mounted to the edge. No more holes in Joe!
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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