So i decided to embark on building a Das Liddle Stick from plans  

I got most of the parts laser cut
Will be using a balsa stripper to cut the spars and other strips

Specifications :

Wing Span: 46"
4 Channels
.19-.40 engine (Will use electric motor 25 size)
AUW: Yet to calculate
17gm servos


Some Modifications i have made to the original plans:

1. Plywood Formers instead of balsa formers.
2. Fuselage sides have been cut in two parts.
3. Stick built tail structures that will be sheeted to save weight.
4. Conversion to electric
5. Dimesions and balsa thicknesses have been converted to metric. (I am not an imperialist )



The fuselage joint will be reinforced with a fiber-glass cloth.

And most of the parts can be assembled without any kind of plans

Find pics attached... more pics in the next post....

Any suggestions and comments are welcome

Dimensions & Specs please.

Added to my first post @sundaram ji. Please have a look

Some more pics

Ribs (R-3)
Ailerons
Wing Tips

Setup I intend to use:

Turnigy G25 Motor
50A ESC
Savox 17gm Servos
FrSky DJT VFR-8 Reciever
3S or 4S yet to be decided

Glow Engine Size 0.15/0.25 Please 

Please build fast. Subscribed and following this eagerly.

@sundaram ji... lets see i do have the fuel tank (190cc) and the engine mounts. If i get a 20-25 nitro engine at a good price then consider the plane converted to nitro (will just need to strengthen the firewall ... Build has already started.. will post the pictures in some time 

Started building the tail structures .. fairly easy to assemble

3mm balsa

All of these will be sheeted with 1mm balsa 

All parts glued together with cyano-acrylate adhesive (Fevi-Kwik)

Up next: Sheeting the surfaces

Sheeting completed ..

1mm balsa used for sheeting

Rugged build though. A vertical tongue on the vertical Stab for inserting in fuse and into slot in horizontal stab for more strength?

Yes..  the tongue will be epoxied to the vertical stab...  will be using ply and will reinforce with fiberglass

Joined the fuselage pieces together

Fuselage glued together now will use epoxy to reinforce the formers to the fuse..  and then apply bottom sheeting 

@yashodhanp
Saw your pm.
First let me congratulate you on the quality of laser cutting, which has produced a fine kit.
Though i have not built/flown one, here is my 2 cents worth:
46" span, i guess 9" chord, so 414 sq inch or just under 3 sqft area.
Typical weight for this model is 4.25 lbs, or just under 2 kg.
Wing loading will be about 24 oz/sqft (slightly heavy), but the cubic loading will be about 14.
So it won't be as easy to fly as a trainer (cubic loading typically 9)

(Contd)

@K K Iyer ji, thank you for the praises for the laser cutting.

Your calculations are nearly spot on. I don't intend to use this as a trainer, but more like a slightly agile aerobatic aircraft,  so this should be absolutely ideal with a 25 nitro or a compatible motor.  Plus I absolutely love the simplicity of design and construction of the ugly stick and how nicely it flies.(Not to mention it is an absolute classic.)

@yashodhanp
Stalling speed would be about 25mph/35fps/40 km. Have to land a little over that.
You'll need a cruise/top speed of about 120 kmph or say 100fps.
On a 6" pitch prop you"ll need 200 rps or 12,000 rpm.
If you use a 700kv motor, that's say 10,000 rpm at 14 volts, or 7,000 rpm assuming 70% motor efficiency.
Ie, about 10" pitch. Since you'll need about 10" dia, this means a 10x10 prop.
Doubtful if your 420(?)W motor could pull that. (30A x 14V)
My 2.5kg Solo Star needs 1hp (Super Tigre 40).

Moral: Use a .25 glow.
All these problems will vanish if she weighs only 1.5kg or so.
By the way, this airplane is reported to fold its wings unless you have spruce spars and shear webbing.

I wonder if this analysis is really correct, as this model has been flown with .19s 40 years ago.
If she flies easily with the G25, do let me know. Then I'll have to conclude that all these theoretical estimates are bunkum (or at least too conservative)

Best of luck.

I may just end up following the moral. I.e. :Using a nitro ..however if i do use an electric i will inform you without fail.   

As for the spar, i will be using a spruce substitute which is incredibly strong and is marginally heavier than spruce (i got it from the wood wholesale market here. They call it wood trim for windows, and is shockingly cheap (4.5rs/ foot). I suspect it is spruce only,however they (dealers) denied it.

Will keep you updated with the power system I chose without fail. The main point is the model was designed for .19-.40 nitro engines. So we do have a huge number of options for nitro, while electric is still restricted due to battery constraints, and also cost.

I have heard of this very model flying very nicely on 550W roughly.. so should be interesting

OS 25LA, 0.69hp, ~550W

Hmm  

Now have a difficult decision to take .. Nitro or electric.. since the G25 710KV seems like a very very strong contender    

Attached a picture of the test data

Only ~300W on 3S.

4S would be needed...

Looks like:
11x10 on 4s will cook the motor at 41A
10x7 on 5s will cook it at 33A!

I like my motors raw

Seems like 11x8 would have to be used. And 5S is not practical for an aircraft of this size. (Seems nitro is still best)

I am now choosing between control rod setup  (crossed or straight) kindly help me decide between the two (Find pics attached

Cross is better and is adopted because easier to keep control rods absolutely straight not to get bent like how you have placed. You have to drill holes accordingly in formers. Drill holes for rods very very close by in the middle former. Then you will be able to easily cross them without and bend.