yashodhanp

Hey guys


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 using a stripper


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 imperial guy)


Fuse Sides:




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


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


Any suggestions are welcome

BMatthews

Other than the motor mount former which should be from plywood make the others from balsa. It'll be lighter and you simply do not need the strength for those formers.'

If it were me I'd have used a couple of more flat ribs on each side of the stabilizer. Not so much for the added strength but to keep the covering from pulling the leading and trailing edges to slightly scalloped shape when the covering shrinks.

yashodhanp

Progress Report

Assembled the tail structures and sheeted it with 1mm balsa

BMatthews

Oh! The sheeting sort of takes away the point of my suggestions above....

Good choice with the 1 mm sheet. Lighter but still strong enough as long as you can keep kids from poking it with their fingers.

yashodhanp

Hehe ,certainly.. i intend to glass the entire structure if i go with nitro . However if i will stay with electric then i will pay attention to your suggestion of children poking it =))

yashodhanp

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

BMatthews

I see you went with the plywood formers. Truly though there is simply no need for plywood formers unless they do double duty for holding things like landing gear or possibly if you use them as mount points for wing bolt blocks. Otherwise they are mostly there to just hold the sides apart and in the right place until you add the top and bottom sheeting. So all in all I'd skip the reinforcing idea. Especially since fillets of glue is a poor weight to strength option. The best place for glue is between two faces that fit smoothly and snuggly together.

yashodhanp

Yes i did use ply formers since i ran out of 5mm balsa

I Guess CA should be strong enough to hold it in place

It would be of great help if you help me chose a control wire setup (find pics attached) i.e. crossed or straight

Regards

BMatthews

With tube in tube or wire in tube it makes almost no difference. However with either it produces less friction and thus less binding if you can avoid any kinks. So I would chose straight or crossed based on where the tubes exit the sides at the tail and how the pushrods will line up with the control horns.

But that brings other issues to consider. Ideally the pushrods for tube in tube need to connect to the horns as close to 90 degrees as possible. But that can mean we need to use a long unsupported external run for the inner rod. One option as shown below would be to angle the horns so as to allow a shorter inner tube or flex cable run to the horn but still meet the horn at a right angle. If you do this then you will want to cross over the tubes within the fuselage at a point where it provides the suggested straightest run from the exit point to the horns. To do this the cross over will be back farther than you show. You want the cross over curves to be tangential to the external line to the horns.

Now in reality we often don't do this. Getting "close enough" is generally close enough But if you're keen on minimizing the amount of differential control surface throw so that the insides and outsides are all the same you might want to cross over the tubes and even wedge mount the horn as shown to achieve good 90 degree angles.

Of course this assumes that you know which of the holes on the control horn you will use as well. Since you're doing an Ugly Stik you will likely want to consider the lowest or second lowest holes on the horns to achieve a good amount of throw angle.