Mighty Mini Mitsubishi A6M Zero Swappable - Build Thread

GregC540i

New member
image.jpeg I pretty much finished building it. I balanced it out at an inch to the first crease behind the leading edge. I had to add 21g of weight in the front to balance it out. I stuck the esc just under the top part of the cowl. I'm planning on running a 3s 850 25C battery in it.

I wil paint it after I maiden the plane. So far a very good design and a fairly easy build.

I just have to wait for the winds to die down a bit and then I can maiden her.

Thanks for the plans.

GregC
 

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localfiend

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That's a very clean build, and that tape is going to add a whole lot of strength. The added weight on the tail hinges is probably why you needed to add the extra weight up front. I think my adding landing gear on mine also helped out with CG.

Your canopy is a bit far forward as well. It's not clear on the plans (something I need to fix), but the canopy sits back off the hatch by about an inch.

I need to finish building version 2. I'm hoping to avoid needing to add any weight up front (it took a nickle's worth of weight on my last build) by removing paper from the inside of the fuselage tail section, using smaller wire for the split elevator, and maybe adding cutouts for the elevator and rudder servos in the wing itself so they can sit further forward.

I think your's will make for an excellent combat plane. That added strength and weight is going to make it a rocket capable of eating a stock mighty mini for breakfast.
 

GregC540i

New member
I thought the canopy was a little forward but I kept it over the removeable hatch. No biggie. I like to reinforce planes with that extreme tape and I know it adds some weight but helps to reinforce it just in case I crash it on maiden that al the time invested isn't all down the drain. I always have fun building these planes and the challenge of it. I don't mind adding the weight. I tend to do that for most my planes. I could have extended the power pod out a little more but I hate how it ruins the esthetics. I can't wait to fly it! I will let the group know how's it goes. Good or bad. Oh I did add a small 2mm diameter rod to help tie the left and right elevator to move in unison. I think that must have been the toughest part of the plane. Using too small of a wire will really make it uneven. I'm no designer, but I know it is a challenge.

Happy New Year all!

Greg
 

GregC540i

New member
IMG_3558.JPG IMG_3559.JPG

I had a chance to maiden her at sunset. I got back from skiing in Tahoe just in time!

She leaped out of my hands and was easy to get into the air. It required a bit of left trim but flew in a manageable way. Nothing too crazy. The mulitstar 2206-2150kv motor with a 6x4 APC prop (I think) and it was very fast! It flew nice!!

Then for some reason I wanted to test out inverted flight and thats when it went down. I should have known. The up elevator didn't move very much. I heard the duff into the ground from 30 feet away! Oh man it was so cool! I absolutely loved it for 1.5 minutes!!!

I'm going to either repair it or I might just build the v5 version and then go the whole 9 yards and do the paint process. Awesome plane, Localfiend! Thank you for developing this plane!!! I'm sorry I got crazy with the plane and crashed it. I will make sure I put the canopy about 1" or so aft of the deck this time.

Happy New Year! (big grin on my face!)
 

localfiend

I like 3D printers...
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I had a chance to maiden her at sunset. I got back from skiing in Tahoe just in time!

She leaped out of my hands and was easy to get into the air. It required a bit of left trim but flew in a manageable way. Nothing too crazy. The mulitstar 2206-2150kv motor with a 6x4 APC prop (I think) and it was very fast! It flew nice!!

Then for some reason I wanted to test out inverted flight and thats when it went down. I should have known. The up elevator didn't move very much. I heard the duff into the ground from 30 feet away! Oh man it was so cool! I absolutely loved it for 1.5 minutes!!!

I'm going to either repair it or I might just build the v5 version and then go the whole 9 yards and do the paint process. Awesome plane, Localfiend! Thank you for developing this plane!!! I'm sorry I got crazy with the plane and crashed it. I will make sure I put the canopy about 1" or so aft of the deck this time.

Happy New Year! (big grin on my face!)

Haha. Oops. I've never done anything like that before.... Well, not more than 5 times at least.... :D

Looks fixable. Just add some hot glue to the crease where it broke behind the wing, and add a bunch of glue to the nose and remove some of the weight you added.

In my pushing the limits video I broke the nose completely off, and cracked the fuse behind the wing when I hit it with a 2x4 trying to get it unstuck from the trellis wire I crashed into. Some hot glue and tape and I was back in the air in 10 minutes.

Did you not have enough throw in your elevator servo? When I finish building v.5 I need to add a CG mark to the plans, and make a throw gauge.

Thanks for the report, glad to see you enjoy crashing as much as I do. It always makes me laugh.
 

GregC540i

New member
I had enough throw in the elevator servo, but the way they are joined or maybe the way I extreme taped the seam, it doesnt move down that far compared to up. Of course, most of my elevator movements are up to send the plane up.

I know I can rebuild/repair the damage, but there are some mistakes I made in the build: I put the AIL servo wires in the wrong side of the spar. I may not put in the wire for the elevator, but instead CA a 2mm carbon fiber rod to join the two. In addition, my control horns were cut down wood pieces from spare swappable series size planes. Even though I cut it down, they were too big, to the point where the elevator surface was transected instead of just fitting within the width of the elevator. I just found a design plan for another mighty mini on FT's website that I am now able to make my own mighty mini control horns.

In the next build, I'm going to improve my mistakes and use appropriate sized pieces. I know it will fly just as good. I have the foam board at my house, but i want to use your full plans to print out at Kinkos so I get an accurate sized print and pieces. After assembly, I will paint it before I fly it. Of course, I will share my results with pics!

My CG seemed to be fine at 1" from the leading edge or even at the first ridge behind the leading edge (which is less than an inch). I did have to trim the plane with a bit of down elevator, but that could simply been the result of the elevator having a slight up incidence and not flush where it should have been. Trimming the plane to the left could have also been the result of the vertical tail not quite being in line with the plane when I glued it in. Otherwise, I trust if all the surfaces were flush and the alignment was more perfect, the plane would have required no trimming at all. These are just my mistakes and issues I need to work out during the next build.

The design is not flawed at all. It is an excellent design.

Greg
 

localfiend

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I had enough throw in the elevator servo, but the way they are joined or maybe the way I extreme taped the seam, it doesnt move down that far compared to up. Of course, most of my elevator movements are up to send the plane up.

Yeah, I've noticed some of that is well on the smaller stuff if your bevels aren't super smooth and the hinge is thicker (adding tape or using just a bit too much hot glue for reinforcement). I've been making the hinge areas on all my smaller planes as clean as possible and at least 45 degrees. The extra room there seems to help.


I know I can rebuild/repair the damage, but there are some mistakes I made in the build: I put the AIL servo wires in the wrong side of the spar. I may not put in the wire for the elevator, but instead CA a 2mm carbon fiber rod to join the two. In addition, my control horns were cut down wood pieces from spare swappable series size planes. Even though I cut it down, they were too big, to the point where the elevator surface was transected instead of just fitting within the width of the elevator. I just found a design plan for another mighty mini on FT's website that I am now able to make my own mighty mini control horns.

Carbon is a good idea. I've just started building v.5 out of Ross foamboard and haven't decided if I'm going to use carbon rod, or just much smaller wire (Mighty mini pushrods). I'll also be removing all the paper from the inside of the tail area.

Just finished laying out all the plans pieces. First time I'm not building from scrap foamboard. Looks like it all fits nicely on one sheet with a decent amount of leftovers.

 

localfiend

I like 3D printers...
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Oops, leading edge line on the wing was red and not black. It's fixed now. If you've downloaded the v.5 plans take note of it.
 

GregC540i

New member
Localfiend:

I noticed an issue with me building #2 based in your v5 plans. The wing spar is too long. I noticed that you shortened the under side of the wing to help move the servo inward or you made the wing longer? When looking to see where the servo will go, I noticed the wing spar is sticking out. I simply cut it, but just wanted to bring it to you attention.

I did the cf rod for the elevator. I used a 2mm cf solid rid of about 4-5" long. I left about 2" from the ends of the elevator. I used the rod to dig a shallow trench so the cf rod will be recessed at the leading edge of the elevator. I then used CA to glue it in after using some sand paper to toughen the cf rod. I flipped the elevators all the way so that when I glued the rod in, the elevator would be as perfectly aligned as possible. Now the elevator moves in unison and there is little to no twisting so far. I have yet to hook up the control horn and test it out further. I think this will be the better way to go. I also did not remove all the foam under the vertical stab or the foam between the elevators. I only cut out as much as I needed.

I used some sub 5g servos. They are Turnigy 1370A servos instead of the HXT500's I was using with the first. They are smaller and lighter and should be strong enough to handle this plane. I installed them just ahead of where the skewer is used to secure the canopy. I did have to shorten the pegs so that the servo horn has the room to move. I used some extreme tape to strengthen it and to prevent some tearing. This way I can put the servos closer to the CG of the plane for better balance. So far on initial tests, I probably won't have to add any weight. I did beef up and reinforced certain areas in the front just in case. I noticed in the wreckage that the top part of the fuse is weak because of some large holes and guide slots. I extreme taped that area to prevent tearing with prolonged use.

I've included some pics of my build process so far. I hope they help.

image.jpeg

GregC
 

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localfiend

I like 3D printers...
Mentor
Ross foamboard pieces cut out. I'm also adding an end cap to the cowl. I'll be using the F power pack this time rather than a Baby Beast motor and 30 amp ESC.



The Ross board does everything great, except removing larger sections of paper. It's a big pain. I gave up trying to pull it off and ended up skinning it like an animal.





Not as pretty as I would like, but no one will see that part when it's all closed up.





Localfiend:
I noticed an issue with me building #2 based in your v5 plans. The wing spar is too long. I noticed that you shortened the under side of the wing to help move the servo inward or you made the wing longer? When looking to see where the servo will go, I noticed the wing spar is sticking out. I simply cut it, but just wanted to bring it to you attention.

Yeah, I saw that when I started building the wing. Forgot to shorten it. I've got a couple little things I've found like that so far that I'll be fixing.


I did the cf rod for the elevator. I used a 2mm cf solid rid of about 4-5" long. I left about 2" from the ends of the elevator. I used the rod to dig a shallow trench so the cf rod will be recessed at the leading edge of the elevator. I then used CA to glue it in after using some sand paper to toughen the cf rod. I flipped the elevators all the way so that when I glued the rod in, the elevator would be as perfectly aligned as possible. Now the elevator moves in unison and there is little to no twisting so far. I have yet to hook up the control horn and test it out further. I think this will be the better way to go. I also did not remove all the foam under the vertical stab or the foam between the elevators. I only cut out as much as I needed.

I just used smaller wire, couldn't find my larger carbon rod. It's the mighty mini sized pushrod wire whatever size that is. If you get all the bends straight so that it lays flat on a table the wire works great. No twisting at all, the hot glue holds everything in place very well. Probably didn't need to remove as much foam as I did, but hey, it saves weight. :D





Plenty of deflection:





I used some sub 5g servos. They are Turnigy 1370A servos instead of the HXT500's I was using with the first. They are smaller and lighter and should be strong enough to handle this plane. I installed them just ahead of where the skewer is used to secure the canopy. I did have to shorten the pegs so that the servo horn has the room to move. I used some extreme tape to strengthen it and to prevent some tearing. This way I can put the servos closer to the CG of the plane for better balance. So far on initial tests, I probably won't have to add any weight. I did beef up and reinforced certain areas in the front just in case. I noticed in the wreckage that the top part of the fuse is weak because of some large holes and guide slots. I extreme taped that area to prevent tearing with prolonged use.

I also thought the power pod mount could use some strengthening. On this build I glued a couple squares of foam to either side of the mount. After the wing went in, I also added a square between the top of the wing and the mount. It should go through hard crashes much better now.




The 1370A's will work just fine, they're actually what I used in my first build, and I've moved them over to this one. Dunno what they weigh, I think they're around 4 grams. Had them in the toolbox and was out of 5g servos last time so it's what I used.

All snugged into place. I embedded the servos into the wing itself to add a bit of extra room and fit my receiver into the middle fuse support. It's a full size receiver, but I like to remove the case for mini builds.




I'm painting the Ross board without any minwax. I did 4 light coats and then one medium coat using Krylon Fusion. Minwax probably would have let me use less paint, as the paper was absorbing the Krylon pretty good.




Probably should have weighed this thing before painting, but I was in the zone and spaced.

It's a good deal lighter using the F power pack. I think with the smaller wire, the paper removal, and getting the servos a bit further forward I won't need to add any weight the nose. With the prop on it's pretty much balanced as it sits.



The cowl looks funny at the moment. I glued a ring of foam to the end, then cut a bevel, sanding things smooth, and am currently playing with Mod Podge to get a smooth finish on the beveled portion.
 

GregC540i

New member
Awesome! Man you were on a roll! I'm not sure how much mine weights. I know it probably weights more than yours, but I don't mind. The Mulitstar 2206-2150kv motor is plenty of power for me. I left off the under part of the rear part of the plane to save weight, but I think it will cause some drag. Maybe simple clear packaging tape will suffice. I flew the first one with the cavity open and it was fine for all the 1.5min I flew it!

I'm not so good at bending wires perfectly so I went the easy route with the cf rod.

I think it took me almost 4 hours to cut out all the pieces. It took me another 4 hours to do all the gluing of the parts except for the turtle deck area. I did glue the turtle deck in about an hour last night and then started to coat the plane with polyurethane to water proof it a bit. I'm currently painting it and letting each layer dry.

I also did add some squares of foam to support the sides just like you did. I also did bend the power pod's receiver ends to contour with the insides of the fuse. That way I can make sure the battery is all the way forward as much as possible. I also glued it along its entire length which probably will also proved more strength to the front end.

I spent some making some decals. I plan to make mine look like the FMS 750, 1400mm zero. MightyMiniZero-Decals.jpg I haven't printed it out yet for myself. The only issue is I'm worried that the numbering might be too big or small. I plan to use a thin amount of CA to glue the decals on.

I wish I could get mine all done to fly today, but rain is in the forecast for the remainder of the week. We need the rain, but hampers our flying schedule! Therefore, more hobbying!

Greg
 

localfiend

I like 3D printers...
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Awesome! Man you were on a roll! I'm not sure how much mine weights. I know it probably weights more than yours, but I don't mind. The Mulitstar 2206-2150kv motor is plenty of power for me. I left off the under part of the rear part of the plane to save weight, but I think it will cause some drag. Maybe simple clear packaging tape will suffice. I flew the first one with the cavity open and it was fine for all the 1.5min I flew it!

I have yet to attach that bottom piece, it'll fly just fine without it. I put it there for people who might want to cover it, but you don't notice in the air, and when it's on the ground, you don't see it either.



I also did add some squares of foam to support the sides just like you did. I also did bend the power pod's receiver ends to contour with the insides of the fuse. That way I can make sure the battery is all the way forward as much as possible. I also glued it along its entire length which probably will also proved more strength to the front end.

That's what those power pod receiver ends are there for. Bend them and glue them against the fuse sides.

I spent some making some decals. I plan to make mine look like the FMS 750, 1400mm zero. I haven't printed it out yet for myself. The only issue is I'm worried that the numbering might be too big or small. I plan to use a thin amount of CA to glue the decals on.

Those are cool. I thought about doing a full set, but I'm lazy and waiting for Rasterize to finish his graphics for it.
 

localfiend

I like 3D printers...
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Working on decals now. Covered them in clear packing tape before cutting them out, then sprayed the backs with a bit of 3M Super 77 spray adhesive.

 

GregC540i

New member
Looks fantastic. I really like the cowl. It looks much better than mine. how did you get it so smooth?

I'm in the final process of letting the polyacrylic spray dry over the decals. I still need to install the control horns onto the surfaces. After that, she is ready to fly. I will post some pictures of it in the end. I think my red dots might have been a little too big for the side of the fuselage. Oh well. It will help with flying visibility!

I can't wait to fly it again.

Greg
 

localfiend

I like 3D printers...
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Looks fantastic. I really like the cowl. It looks much better than mine. how did you get it so smooth?

I'm in the final process of letting the polyacrylic spray dry over the decals. I still need to install the control horns onto the surfaces. After that, she is ready to fly. I will post some pictures of it in the end. I think my red dots might have been a little too big for the side of the fuselage. Oh well. It will help with flying visibility!

I can't wait to fly it again.

Greg

I used some Mod Podge I had bought earlier for a different project. It's kind of like a thicker Elmer's white/school glue that dries clear.

It kind of took a round about way of getting there, but I like how it turned out.

Traced around the outer front edge of the cowl and made a ring shaped end cap:



Hot glued the ring to the end and cut a bevel around the edge. I was hoping to leave things here and started coloring stuff in with a sharpie to see what it would look like. Didn't like it, it was too rough so I decided to fill in the foam.



I used several coats of mod podge and a bit of sanding to try and get things smooth:



Coats of Mod Podge seem to try in about 20 minutes, though It's best to double that time if it's the final coat before paint. After the above dried, I went and put on a single coat of paint. Once again I didn't like it. Stuff still wasn't smooth enough (My bevel job was rough) and I knew the paint was going to be uneven. The uncoated paper was soaking up the paint. You can see how it's way darker where the mod podge coating is.



So I did some more sanding and then coated the whole cowl. Think I put on three coats this way. You'll know it's time for a new coat when it all turns clear.



Once the mod podge has dried (15-20 minutes) you can wet sand it. The mod podge gets sticky again when wet. Took some 400 grit sandpaper soaked in water and quickly smoothed out the brush strokes. Then I wiped the cowl down with a slightly damp paper towel. It's very easy to get it smooth.



After that last step, let things dry then paint.

I'll probably do this again, my larger Zero really needs something covering up the front better, but I believe it can be down quicker.

Notes for next time:

Remove paper from the back of the ring
Get the final bevel sanded into the foam before applying anything
Smear a bit of hot glue into the bevel as a preliminary sealer.
Apply a couple coats of mod podge over the hot glued bevel and the entire cowl
Wet sand/smear down brush strokes
Paint

Should go pretty quick if the above works. Might be something easier to smear into the open pored foam too.
 

GregC540i

New member
I tried to maiden her this morning after the rain had ended. It didn't go well, unfortunately. I duffed it several times before I even got to fly her. She eventually did fly. I bashed up the front end, but all the rest of the plane is in good shape. I'll have to make a new power pod because that got all bashed up. A new prop will have to put on as well. Instead of a 6x4, I might try a 7x5. Amp draw shouldn't be a problem. I'm not yet sure if the motor can handle that size of a prop.

I almost had no elevator throw. The small servo I installed is too weak. Plus I had to glue the servo to a square piece of foam which in turn was glued to the side of the fuse. Because of the several crashes, it started to come loose. I think the ELE servo needs a 5g instead of the smaller one. The AIL servos were plenty fine. It felt comfortable. I'll play around with it some more in the future.

I wish this one flew just as nice as the first! Oh well. It was a project and I did get to fly it a bit.

IMG_3602.JPG IMG_3604.JPG IMG_3606.JPG IMG_3609.JPG IMG_3610.JPG IMG_3611.JPG IMG_3612.JPG IMG_3613.JPG
 

localfiend

I like 3D printers...
Mentor
This sounds interesting. I'd like to see what you come up with. :)


If it goes well maybe I'll send you some sheets to play with. Don't think I need 50 of them. :D


I tried to maiden her this morning after the rain had ended. It didn't go well, unfortunately. I duffed it several times before I even got to fly her. She eventually did fly. I bashed up the front end, but all the rest of the plane is in good shape. I'll have to make a new power pod because that got all bashed up. A new prop will have to put on as well. Instead of a 6x4, I might try a 7x5. Amp draw shouldn't be a problem. I'm not yet sure if the motor can handle that size of a prop.

Darn, that's too bad the maiden didn't go well. Your plane looks awesome. You did a better job painting than me, I didn't use any masking tape at all. The nice thing about these little planes is that the Power Pod, Cowl, and even hatch are easy to make replacements for, the rest is generally to strong to break badly unless you do some Olympic worth cartwheels.

I'm thinking you have to be massively nose heavy with the motor hanging way out in front like that. Are you balancing directly on the leading edge? Starting CG should be 1" back from the leading edge near the landing gear cutouts. You've got some leeway like all CG points, and it can probably be moved as far back as 1.25". I plan to do some more precise CG measurements once I get a change to fly this one.

Found a 2x8 in the garage and drilled some holes for a couple pencils. I usually just use my fingers but this is probably better.

This is about 1.125" back. I'm being risky for my first flight. :cool:







You also seem to be approaching Funfighter wing loading. It should fly like that, but It's going to behave like a Funfighter. I thought I was a bit heavy with all the coats of paint, the mod podge soaked cowl, and the addition of landing gear with big wheels.

189 Grams ready to fly without battery:



226 grams with 500mAh 2s. Could probably put in an 800mAh 2s and still be under 250 grams. Take that FAA. :mad:



269 grams with a 850mAh 3s.




Also, I don't think I would go bigger on the prop unless you are very careful with the throttle. I have one of those motors on a Twisted Hobbies F22, and it can get very hot in the summer with 6045 prop if I push it too hard. I'm new to the hobby though, in this cold you may be able to get away with more.

I almost had no elevator throw. The small servo I installed is too weak. Plus I had to glue the servo to a square piece of foam which in turn was glued to the side of the fuse. Because of the several crashes, it started to come loose. I think the ELE servo needs a 5g instead of the smaller one. The AIL servos were plenty fine. It felt comfortable. I'll play around with it some more in the future.

I wish this one flew just as nice as the first! Oh well. It was a project and I did get to fly it a bit.

Might be your taped hinges - that really adds to the force needed to move them. I used the same servos you did for my elevator and rudder, used the standard Mighty Mini horns, and the middle hole on the servo arm. Here's what max throws for aileron and elevator look like on mine:


I'll probably reduce the Ailerons and Elevator by 20% after the first flight for normal flying. Low rates will probably be 70% of whatever that comes out to be. Rudder will probably stay where it is, might go up or down. I'll be making a throw gauge after the flight for the next plans revision and first non beta release.