Jackson T
Elite member
So I've pulled apart my BL motor, how do you get the magnets off?
4 Metre Glider Scratch Build
- Thread starter Jackson T
- Start date
TooJung2Die
Master member
Pop them out with a small screwdriver.
Not a full snap, but I did hear cracking on one which prompted the thin plywood strip backing
Funny, my problem has always been the exact opposite!
In my experience, a hard crash into a chain link fence is great at ripping apart brushless SunnySky 2204s.
Kudos to @TooJung2Die for the brushless motor magnet idea. Just awesome.
Jackson T
Elite member
Done most of the hatch! Now I just need to get the magnets off my cooked motor and glue them onto the hatch and fuselage.
That moldy looking stuff on the hatch is from when I put the sheet balsa in my brother's car. turns out he had spilled some oil recently, and it wasn't fully cleaned up. Oh well, at least it's on the inside!
That moldy looking stuff on the hatch is from when I put the sheet balsa in my brother's car. turns out he had spilled some oil recently, and it wasn't fully cleaned up
. Oh well, at least it's on the inside!
Beautiful work.
TooJung2Die
Master member
That hatch looks good. The tricky part of gluing the magnets is positioning them so they touch with the hatch closed. Even a slight gap between the magnets reduces the bond. You don't want the magnets to touch too soon and prevent the hatch from completely closing. I had to be satisfied with a close fit. If you come up with a good technique to get it perfect let us know.
I use plastic baggie from random RC parts to keep the two magnets separated just a tiny bit and then set them with epoxy into both the hatch and fuselage at the same time. Let it sit for a day to cure really really well before opening it up or it'll be a sticky mess than never sits level (ask me how I know
). When it comes time to open it up, the plastic might stick to the epoxy a little bit, but since it's both sides of the baggie the magnets separate easily and then the plastic can be peeled away more carefully without breaking the balsa.
TooJung2Die
Master member
Sounds doable. You'll have to be sparing with the epoxy so it doesn't sneak around the plastic and form an epoxy bond between the hatch and fuselage. I'll try this next time.
Speaking of epoxies, 5 minute epoxy doesn't bond well to the magnets. They will easily come off. It has to be 30 minute cure or longer. I used CA glue. It bonds to metal very well but it can migrate so gluing the hatch down with it is a risk.
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<rant>
I know they try to sell 5, 15, and 20 minute boxes they claim contain epoxy, but I call BS on that. I firmly believe that a modeler should not buy anything less than 30 minute epoxy. Anything less doesn't penetrate, doesn't guarantee a waterproof seal, has much less strength, and generally just makes a big mess to clean up when it fails to work right, which happens more often than not.
Just my 2 cents and personal experience here, but I say don't waste the money.
</rant>
I know they try to sell 5, 15, and 20 minute boxes they claim contain epoxy, but I call BS on that. I firmly believe that a modeler should not buy anything less than 30 minute epoxy. Anything less doesn't penetrate, doesn't guarantee a waterproof seal, has much less strength, and generally just makes a big mess to clean up when it fails to work right, which happens more often than not.
Just my 2 cents and personal experience here, but I say don't waste the money.
</rant>
Jackson T
Elite member
Magnets installed! First I cut a recess in the hatch so the magnets sit flush with the side thingys, and glued them in with CA. I decided to put some reinforcement at the rear between the magnets with some 5mm x 3mm, as it felt a bit weak.
Then I measured from the magnet to the inside of the hatch top, and made a mark on the inside of the fuselage that far down plus the width of the magnet. (sorry for the fuzzy photo, the camera didn't want to focus).
Then I glued in a small piece of balsa to act as a shelf for the magnet, and glued the magnet on top.
The left hand side is perfect! the magnets just touch, and the hatch surface sits perfectly flush with the fuse. The right hand side magnet is mounted a tad high, so the hatch is raised like half a mm or something from the fuse. You only notice when you get up close and look for it. Overall I'm very happy with how it all turned out!
Then I measured from the magnet to the inside of the hatch top, and made a mark on the inside of the fuselage that far down plus the width of the magnet. (sorry for the fuzzy photo, the camera didn't want to focus).
TooJung2Die
Master member
And sanding, and sanding, and sanding...
Good thing it's only balsa.
Did you reinforce the slot in the rib with the vertical grain? That’ll be a weak point due to how close the slot is to the edge of the rib.
Jackson T
Elite member
Yeah, my dad suggested maybe putting the paddle pop stick in the trailing edge, but I was sceptical of it splitting the trailing edge. Maybe if I used something thinner...
It has the normal 2.5mm thick horizontal grain rib, as well as the 1.5mm vertical gran balsa you see in the photo, so it has 4mm total thickness with two grain directions.
bracesport
Legendary member
@Jackson T - I am so looking forward to the covering process on this one!
Jackson T
Elite member
Yeah, it's gonna be a lot of work. Using a clothes iron isn't exactly ideal either, but at least I didn't have to pay for it@Jackson T - I am so looking forward to the covering process on this one!
. On my first plane, I overshrunk the tailplane with a heat gun, and the shrinking film broke the trailing edge . At least this time all the trailing edges and stuff are pretty sturdy, and I have a bit more practice.
bracesport
Legendary member
I just use a clothes iron - if it works it works!
