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Home-made sub-250g Models


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Chuckle in flight.jpgChuckle Home-build.jpgFlidl 2.jpgAlthough I am no builder, I recently decided to set myself the task of making one or two sub 250g RC models for my grandson, so he could fly them locally and without the new DRES registration. He's miles away from a club, and cost is also an issue, so it became an interesting project for me to make some really lightweight models "on a shoestring budget".

My first attempt was made from grey pipe lagging and an old wing from someting I bought years ago. I called it "The Lobster" because of its colours and the fact it needs to be lobbed into the air!

My second attempt was to power one of the chuck gliders from Lidl. It flies beautifully but came in in a little over my target 250g.

The third attempt was called "Chuckle" (it also needs chucking into the air) and this is well under 150g and is made from corrugated plastic sheeting called Proplex, bought from Wickes.

Anybody else been doing this kind of thing? Let's se.

Lobster.jpgFlidl 1.jpg

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I like your profile fuselage model, I have been thinking pod and boom.

I haven't done it yet so you may have to wait a while to see any results but working below the 250g limit is what I am contemplating now. My first step has been to study balsa/carbon tube 1 meter wingspan DLG's. Construction must be strong and they are well below 200g so scope to add electrics. Could be the inspiration for a slow flying motor glider type of plane, so maximising flight time from a small battery.

Should really finish what's on the bench already but the mind does wander!

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  • 1 year later...

If minimum cost is not the main goal, my effort was using the available ex-Keil-Kraft Ajax kit, which makes into a slow flying electric RC. In fact, I made a smaller span matching wing to make it a biplane, weighs just under 250g. Rubber free flight kits, & plans make good light park flyers.

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I have had a lot of fun with the two sub 250 gm home built models show here. Both the airframes were built from materials I already had in the workshop, and both are powered by a 2s 300 mAh battery. Weights ready to fly (with battery) are 89gm for the wing and 146gm for the conventional model.  Flight times are about 5 minutes and both are fully aerobatic, although the 'wing' doesn't have a rudder which limits it for some manoeuvres.

They will fly OK in surprisingly windy weather - as you can probably tell from my "lockdown" hairstyle ?.

 

Dick

 

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2s300mah battery to power what motor and prop please ?

 

I know nothing of modern electric flight and have to start somewhere...

 

I can research tiny light servos, a tiny and light Rx but need help with the prop motor ESC combination...or do I go for the combination that the vintage model company uses for the yellow cub trainer and avoid using full throttle ?

 

Ideally the vmc combo would/could be used for planes of similar size, weight, wing area models ?  But lighter weight smaller size stuff to make a soarer or electric Lidl chuck glider ? As that can be made to fit motorcycle transport ?

 

Help greatly appreciated.

Edited by Rich Griff
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With a 2S battery, you'll need a reasonably high Kv motor (say 1700-2100) although the larger Lidl glider pictured above uses a cheap 1540Kv motor.  A 10-12A ESC is fine but use a smallish prop (say 5x3).   I've always sourced motors and ESC from HobbyKing for these lightweights, but of course it depends what stock they've got.

 

I've since made a small delta wing from Wickes Proplex sheeting covered in self-adhesive book covering (The Works sell this in various colours).  Again it's a sweet flyer.

I've just started electrifying the new Playtive Junior chuck glider currently on sale from Lidl at £3.99.  Real flying on a shoestring.

 

If you want a simple kit that's small and light that flies really well, look at the Crack Wing for about £25.  (Robotbirds and others sell it).  They'll sell you all the innards too.

Takes off vertically (yes really!)  Great little model.

 

Crack Wing 2.jpg

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Playtime chuck glider from Lidl, I got 2 today, would be very interested in your conversion to electric powered as I would like to do that as well as a small slope soarer.

 

Taking one to the field to see how well they GL dear first...

 

Have done research on some of the materials you have mentioned, some more pictures and your methods would be very informative.

 

I too lost the money tree in the garden....so have to think of cheaper raw materials rather than balsa and solarfilm.

 

As said I know nothing of electric powered flight and micro servos, but willing to learn.

 

From next month I am going to have so much free time that needs filling.

 

Thanks

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4 hours ago, Rich Griff said:

2s300mah battery to power what motor and prop please ?

 

I know nothing of modern electric flight and have to start somewhere...

.........................................

Help greatly appreciated.

I used a c2214 2280kv motor from Robotbirds which doesn't seem to be available now - although it has an identical spec to the more expensive Multiplex motor which should give you some idea of what to look for

https://www.multiplex-rc.de/produkte/314944-roxxy-bl-outrunner-c22-14-2280kv

In practice, any motor with a kv of between 2000 and 2500 and a weight of between 10gm and 20 gm should work OK on 2s on a small model like mine. Have a look on the 4-Max website.

I tried a few props and ended up using a 5x4.3 as the best compromise.

 

Dick

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Here are pics of my most recent sub-250g model, which also flies really well - on anything from 2S/180 - 2S/450.  (The sunglasses are to indicate size)

 

If  you really want to keep costs down you need to improvise a fair bit.  For instance, never throw away old plastic store loyalty cards - you can cut them up with scissors to make control horns, motor-mounts etc.  Also some bottle tops and the tops off Bovril/Marmite jars make brilliant motor mounts.  See both of these ideas on the Flinger Delta in the pics.  Use UHU-POR glue (not standard UHU which melts plastic and foam) to stick everything together.

The Lidl Junior Glider is very small so a really small motor/6A ESC/prop system is needed, as well as a very small lightweight parkflyer receiver.  I bought all my sub-micro servos, motors, props and ESC's from HobbyKing.  They are quite cheap but their stocks are up and down so you'll need to get them when they're in.  Another good source for electrics is Banggood, but you'll need to be patient because they come from China.  Robotbirds usually keep stocks of sub-micro servos.  If you need a good but really cheap transmitter (TX), look at the FlySky i6, also available from Banggood (about £40 for 6Ch TX with 20 model memories - great for park-flyers).  They also do a great tiny little 6 channel receiver (RX) for about £8 but you'll need to order it separately, as the TX comes with a larger one which is too big for micro models.

 

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Flinger Delta Annotated.jpg

Flinger Delta 5C.jpg

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I really like the "Marmite jar lid" motor mount - brilliant idea, and I will keep my next one and not throw it in recycling as usual.

BUT - I suppose it is one of those things you either love of hate ?

 

These small models really are a lot of fun.

 

Dick

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If you can build light enough almost anything is possible.

13Aug17.JPG.3ff40479654f3efbf49abe6786853004.JPG

A DH Venom, 40 mm AEO EDF, three 2.5 g servos, a micro rx, 810 mm span and with a 1400 mAh 2s it still only weighs 202 g.

Loops and rolls easily. Go gently on the power and over 10 minutes is there.

Edited by Simon Chaddock
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Hobby King used to supply them in two types one for 1s only operation, the other would handle 5V from a BEC but not 6V.

They used tiny Molex? plugs so they had to be replaced with normal type to suite the Rx.

The only pictures I have before the fuselage skin was completed

Complete1.JPG.a3e981c16d964f7a09fa219e685a686c.JPG

All pretty compact. The ESC is on top of the duct with its heat sink in the duct airflow. The 6 ch receiver is low down in between the inlet ducts.

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The servos leads had yet to be connected. 

A view up the exhaust showing the 40 mm 6 blade fan and motor.

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If it helps a video of it flying and kept low for the benefit of the camera.

https://www.youtube.com/watch?v=jCbmOkg_JTo&t=107s

I do have some other sub 250g RC planes. ?  

 

Edited by Simon Chaddock
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  • 2 months later...

Using thin 2 mm Depron a scale sub 250 g plane can be quite big. This Super Cub has a 40" (1016 mm) span and weighs 242 g with a 1000 mAh 2s on board.

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It weight is 'writ large' on the wing just so everyone knows.

The wings are 2 mm Depron skins over 2 mm Depron ribs with no spar just a 2 mm Depron shear web. This means the balsa wing struts provide most of the bending strength. The wheels are laminated from 6mm grey Depron.

It uses four 3.7 g servos. The 6x4 prop is virtually a scale diameter.

 

Unfortunately 2 mm Depron is no longer available so I wondered if a sub 250 g 'printed' plane was possible.

I had no success printing a complete airframe, It was simply too heavy however it did work using 'stick and tissue' principles. The airframe thus took on a conventional appearance it was just the sticks were printed including the spar.

More a power glider than anything else it has the same 40" span but with only 3 servos as it is flown AET (bank and yank).

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Apart from the glass fibre 'fishing rod' tail boom and the tissue everything else is 3D printed.

With an 850 mAh 3s on board it weighs 222g.

    

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  • 1 year later...

Resurrecting an old thread here! I’ve been having a lot of fun with this scratch build. One sheet of 6mm insulation foam, one hour build using hot glue, and 248g ready to fly with an 850mAh 3s on board. Motor is an 1806 drone motor running a 6x3 prop. It’s surprisingly quick - planning a pylon racing competition at our club. And if you crash it’s £2 for another one…

 

8EEDB1AB-78E8-459E-87A3-D565B0CE51D6.jpeg

Edited by Lipo Man
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Here's my first go at an SEMFF depron funfighter, weighs in just a tad under 250g, a Mustang III with the Malcolm hood. 30" span, laminated 6mm depron, 1300kv pole and stator outrunner, 2s1p 450 mah lipo, GWS 8x6" slowfly prop. This one has everything inside the profile fuselage accessed through hatches.

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My other SEMFF fighters, which were built by my pal Bob have the gear mounted on the outside and the battery in an open slot - all use the same basic configuration, all weigh 202 - 240g and all fly well. The wee Zero is the best flying model.

 

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My Lidl XL glider powered conversion.

FoldProp1.JPG.863470b02b847476a1f2391a7ca20cc7.JPG

It weighs 226g with a 950 mAh 2s.

It was the early version Lidl XL which had really thick trailing edges on all the surfaces  My OCD about aerodynamic efficiency drove me to simply extend the trailing edges with Depron to give a 1mm thick edge.

Extension.JPG.6930a2479578a590e49a4d44cfb83e00.JPG 

I judged these extensions would have sufficient area to act as control surfaces so no modification to the original foam would be required.

The Lidl has dihedral wing tips so these extensions became the ailerons. The section inboard was fixed and just added to the wing area.

The extensions to the tail plane became the elevator which required a short carbon tube joiner.

The fin extension was fixed. The plane is flown AET (Aileron , elevator, throttle)

As it was intended to be a powered glider rather than a sports plane it uses a tiny 1806 motor driving a 6x3 folding prop.

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The nose profile is carefully blended into the spinner.

The battery, ESC and 4ch Rx fit within the slightly hollowed out cockpit.

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The aileron servos are buried flush with the wing underside.

AilServo.JPG.a455a6a2f94881caf658e14dd7de8388.JPG 

  The elevator servo is buried in the fuselage just behind the cockpit with nylon pull/pull cables back to the elevator.

EleServo1.JPG.eeef44c72a2fc5322427e11cc3b82f02.JPG

Always a modest flyer the big battery gives a substantial 40 minute 'cruise' endurance. Of course with its reasonable aerodynamics and a wing loading not that much greater than as a chick glider it thermals very nicely. Small and slow it can stay in the core of even a weak UK thermal.

As a concept maybe not everyone's cup of tea as a Lidl conversion.

A video of its maiden flight.

https://www.youtube.com/watch?v=vZcwwmIA_UE

A bit shaky to start but once trimmed out easy enough.

EleRud1.JPG

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