[caffeine]

KMart sell a large foam glider, and the same product is sold in Europe via Lidl. There's a huge community around converting them to RC, whether as RC gliders, powered aircraft or even ducted fan swept wing jets!

My son and I picked one up from KMart last week and set about converting it. I bought tiny little 4.5g servos, a 2306 motor and I've ordered a 20A ESC (motor draws 10A with the 5x4.3x3 prop) While I wait for the 20A ESC to arrive I've used my 35A ESC out of my Bix3.



I went to Jaycar and bought some nichrome wire, and I made up 2 hot wire foam cutters. a bow shaped one for making big straight cuts and a scoop shaped one for scalloping out the inside of the nose of the glider,a nd for making tube shaped grooves where reinforcing rod is to be added.



I used my bench power supply to send the appropriate current through them.

I then cut the nose off the glider using the bow cutter, and traced out the cut shape onto plywood to serve as a template. I cut out the plywood, drilled the necessary holes, and then screwed it to some large standoffs, which I hot-glued into the plane nose. I can now remove this motor mount when desired by unscrewing it from the standoffs.





I then scooped out the foam from the nose, and then inserted my battery, receiver and speed controller.



I installed 1 servo in each wing, and cut out ailerons (the plane has moulded in lines at this point, more where you'd expect flaps to be, but they still give great control authority). I also cut out the back of the horizontal tail surface to make an elevator and used a servo in the vertical stabiliser to control it. I cut a chamfer on the bottom front of the control surfaces and used packing tape on the topside as a hinge. I installed the servos on top of the wing to keep them out of harm's way when belly landing.

I installed a 5mm carbon tube in the wing and fuselage, and a 4mm carbon rod in the horizontal stabiliser to stiffen it all, and it was 'ready to fly'



I set the CG to the same as it was out of the box as a chuck glider (50mm from the leading edge of the wing) but I found that was incredibly pitch sensitive (probably because it's design to do easy loops when chucked by a kid), so I moved it forward about 10mm by repositioning the battery. It flies much more balanced now.

I found that at speed the nose and tail would flutter a lot, leading to control issues and a rapid unscheduled dissassembly. 10 minutes with the hot glue gun and it was back together, and I added more 5mm carbon tube from the underside of the fuselage to the underside of the tail, and I glued 2 tongue depressors to the sides of the 'cockpit' to stiffen that too. It flies beautifully now, and it can cruise around for about 8 to 10 minutes on half throttle with the 850mAh 3s battery I'm using.

I've learned some lessons for if (when) I make another one. I'll put the servos on the underside of the wing, and scoop out far less foam from the nose.

All in all, a fun little weekend project with my kids, and now we have a very robust, easy to repair plane for quick lunchtime flights.

[srl]

Looks good!
No Hobby King now so we have to make do.

srl

[caffeine]

Yeah I've been looking around for alternatives. This ESC I have coming is from eBay so it's probably straight off AliExpress.

I have been considering the 10 pack of 9 gram metal geared servos from AliExpress for $25 shipped, they have a variety of no name ESCs for $4-5 each. I might pick up some of them too. When it's this cheap and easy to repair it is not as scary taking a bit of risk on cheap parts

[caffeine]

My eBay ESC died pretty quickly, so I'm back to using the 35A Bix3 ESC.

I have dozens of flights on the plane now, and it's held up extremely well. Occasionally it will get snagged on grass or a root when landing and tear the foam, but it's hot glued back together and flying again in minutes.

I now have 3 more of the gliders from KMart, another motor and receiver, and 11 props in total. I've gone for a 1900kV (instead of 1700kV) motor this time, and I'll use 9g servos ($25 for 10 from AliExpress) instead of the 4.5g.

I'll also give it full width ailerons and flatten the wing, the current one really doesn't like to roll with the dihedral and the inboard ailerons. I'll also add a rudder.

[caffeine]

I have received the servos and other equipment from AliExpress, and everything works as expected.

My first conversation has a couple of weights attached to the tail to get the CG I want. This time I'll add a rudder servo, which will remove the need for one of the weights, I also have a couple of hobbywing flyfun 20A ESCs on the way, which are significantly lighter than the 30A ESC from my bix3, and even more so than the 30A ESC I received from AliExpress. Using that hobbywing ESC should mean I can remove the other weight from the tail too.

As it's a smaller ESC, I'll also need to remove less foam from the 'cockpit' of the plane, giving it a bit more rigidity and stability.

[caffeine]

My second conversion was a bit of a debacle. I initially had full span ailerons made from plywood, however they messed with the airflow too much and the plane flew like a pig on stilts. I glued the wing back together and cut some outboard ailerons into it, and now it flies quite well.

With four 9-gram servos instead of three 4.3g ones, it's a bit heavier. Add to that I'm using a 1900kv motor instead of 1700kv, and it is a bit of a rocketship. I think I need to swap the 5x4.8x3 prop out for a 5x4.3x3 to tone it down a bit

With the flattened wing it's much more agile too, I turned the rates down to 50% and it's more pleasant to fly now.

[camdoggs]

hey, i was just down at the field and a few members were looking at my delta wing, they told me to reach out and say hi.
looks like i found the other guy buying up all the gliders. lol
i didn't have much luck with the two colour model, just some testing..still got to figure a few things out.

the blue one is made out of a single glider and the other one is out of 2

[caffeine]

That's pretty cool! Did you 3D print the front bit on the multicolour one?

My two are pretty conventional but I've seen some very cool conversions on the Facebook groups.

Yours is up there with them and it shows the flexibility of these cheap gliders 

[camdoggs]

Yeah the underbelly and motor mount is 3D printed and the canopy for the nose. The blue one was a printed motor mount and underbelly ( mostly just to have a flat surface to mount the wing) did you cut the wing tips it get them flat? I have been trying to steam them then bending them with mixed results

[camdoggs]

I have been chatting with a guy on RC page on reddit who has some real wacky glider remixes


https://www.reddit.com/r/RCPlanes/commen...urce=share&utm_medium=ios_app&utm_name=ioscss&utm_content=1&utm_term=1

[caffeine]

did you cut the wing tips it get them flat? I have been trying to steam them then bending them with mixed results

Yes, I sliced them off completely with my hot wire cutter, and then butt-jointed them back on flat with hot glue. It worked extremely well.

[caffeine]

I have been chatting with a guy on  RC page on reddit who has some real wacky glider remixes


https://www.reddit.com/r/RCPlanes/commen...urce=share&utm_medium=ios_app&utm_name=ioscss&utm_content=1&utm_term=1

Wacky is a good description 

[caffeine]

did you cut the wing tips it get them flat? I have been trying to steam them then bending them with mixed results

Yes, I sliced them off completely with my hot wire cutter, and then butt-jointed them back on flat with hot glue. It worked extremely well.

   

I cut a wedge shaped piece off the removed wingtips to make the end flat

It worked extremely well. The blue painters tape doesn't stick to the set hot glue so it's good to use as a temporary support

   

I went a bit overboard with the amount of glue on this wingtip so it's a bit bulgy, but still flies great

[camdoggs]

I haven’t used any hot glue on butt joins because I was concerned about the holding power, I have been using E6000 glue, it takes a few hours to set, but the foam breaks before the joints. You finding hot glue to be ok? What sticks do you use?


Just changed up the design of my elevons, I think the original set up didn’t have enough surface area near the wing tips for any real control authority. 

Hopefully that will do it!!

[caffeine]

I'm finding the hot glue works extremely well with this foam, it's stronger than the foam itself, and can be easily undone with some isopropyl alcohol if I need to move or change anything

[camdoggs]

Ok… I’m back with the Kmark II . Turns out I had my steering reversed and I put the first guy in an early grave. Mark II has better weight distribution and a bigger wing. Just a head up, there was only one glider left at cast towers  . Pics below

[srl]

I've got the tail control services done. Now waiting for some 2mm plastic tube for the linkages. It will be a 2 channel non powered glider.

   

srl

[camdoggs]

Looking great.!!! Just do what I do when you need some 2mm tube… start eating lots of chupa chups. They come with free tube

[caffeine]

Looking great.!!! Just do what I do when you need some 2mm tube… start eating lots of chupa chups. They come with free tube

Haha true! Whenever my kids finish one I pinch the tube from it