Beechcraft Bonanza C35

[Vecchio Austriaco]

Erfolg,

Follow the link I have put in this morning and have a look at middle of page 15 of Danny Fentons thread - for the RDS demonstration model - also with a video. I - copycat - will do exactly the same. (I will not make a demonstration model, but I use the same arrangement). Problem are the 2 adapter parts - I think I make them in Vienna on the weekend.

Edited By Vecchio Austriaco on 09/12/2010 16:45:01

[Erfolg]

Yes, I think that the bent crank system is the one I have seen previously.

 

I think that that version works well, but does benefit from tight tolerances on the slot and ensuring that the friction level is good (material selection issue).

 

The torque ceases to be the same issue, but there is a balance from friction and servo potentiometer issues, sloppy fits can still  lead to a vibrating control surface

 

I think it was some 20 years ago since I saw this system. Certainly not since re-starting modelling,

 

Certainly a neat installation, excellent (looking) for some scale models.

[Vecchio Austriaco]

Just a very qick message fro a windy and snowy Vienna. My fathers lathe was not in best condition as the main belt was broken - but somehow I managed it to produce the RDS servo adaptors.

As my father was building ships in his more active time I found all dimensions of brass rod, but no aluminium. As the parts are very small I don´t think they will change the weight balance of my model.

 

The adapter will be fixed to the cross servo arm by 2 M2 screws. The piano wire which will move the aileron will be held in position by 1 or 2 M3 grub screws.

[Danny Fenton]

Excellent VA glad to see you giving RDS a go. The fit of the piano wire in the pocket is critical. I have found that a little friction is fine so you can make it an interference fit. That is why the material lining the pocket needs to be hardwearing, I hope your material is tough enough to last the test of time.

You may also find that you have to use nuts and bolts to attach the adaptor to the horn as you have to mount the arm on the servo first and the body of the servo may get in the way.

 

I found a great way to mount a servo so that its still removable and used it on the flaps of my Hurricane.

 

Granted for RDS you turn it through 90 degrees but it should work either way. Ignore the collet. It is temporary and is udes to confirm pushrod lengths, it is then removed and one of a matching length is made.

 

Cheers

Danny

[Vecchio Austriaco]

There is practically no friction in the pocket, the material is quite soft (polistyrene) but metal covered. So I think it will keep quite a while.

 

In the brass adapters I did cut an M2 thread, so the screws fit in there without nuts. Lets have a look how it works.

 

The servo arm is fixed to the servo only after the connector is srewed on. This can be done with a small screwdriver through the cetre hole which later will hold the piano wire.

 

Not much progress - but I am busy at work and busy at home. It is also Christmas party time and in a weak moment I invited some colleagues to test and taste some Austrian cusine.... 

[Danny Fenton]

Looks good VA, you got lucky being able to get at the screw through the piano wire hole. My servo arm holes are also tapped but the body of the servo stops access to do them up after the arm is attached   maybe a fine screwdriver would fit the centre screw as you have, will try that.

 

Cheers

Danny

[Erfolg]

Your adaptor seems very good.

 

Well done.

 

I guess your farther did comment, he only come home to use my lathe? Does he clean it, ohhh no, leaves that for me! I wanted that brass bar for............

 

I wonder if a commercially viable system will ever be produced. 

[Danny Fenton]

You can buy all the parts, they are available from the States. But the price is high, and add to that shipping.......They are tricky to set up, everything needs to be in perfect allignment. I think that puts a lot of people off.

 

RDS system

 

Cheers

Danny

[Vecchio Austriaco]

I think you get an RDS system also from Graupner - but not at the size needed for my model.

 

My fathers lathe is cleaner as it was before I used it and he has enough brass rod for the next 3 years....

After Chrismas I will bring my own lathe from Italy - its a 5" machine and I don't really know where to put it into my small flat. But it is a necessary tool as it also has the vertival unit for milling and precision drilling.

 

Not many news from the project itself - but today I received my LEDs for the light system and I collected the electronics from S.M. services 45 min ago.

[Vecchio Austriaco]

I could not resist and had to play with the LEDs which finally arrived.

 

I started to think about the wingtip. It needs 2 LEDs, the red or green position light and a white strobe light as collision warning. As the plane is small I decided to use SMD LEDs. Before you do so go to your optician to be sure your eyesight is ok or properly corrected…
As SMD LEDs are not nice and round they need a cover. And this needs to be transparent. I made quickly a positive form out of hard wood and a negative one from the same material to be able to swage the cover. I used the packaging of a Spektrum receiver as a material source. (This is called recycling!)
With a little heat and patience the oval bubble protection glass was born.For the SMD LEDs a bit of PCB is necessary. As I don’t have the necessary chemistry for etching with me I just scratched parts of the copper surface away using a small file.

The main parts. LEDs in the middle

To solder the SMD leds into position you need to pre-tin the PCB. As the SMD Leds tend to "swim" on the solder it is difficult to fix them in the correct position.

 

Leds soldered into their position and holes drilled for the connecting wires.

Now the contact wires are soldered on and the metal surface of the PCP board needs a bit of white colour to look better. But before the LEDs need to be tested.

The contact wires I arranged neatly with a bit of shrink tube. I am happy with the result of the work.

 

This will be the future position of the light.

Edited By Vecchio Austriaco on 17/12/2010 08:34:06

[Vecchio Austriaco]

After playing with the LEDs back to more serious stuff.

Finally I glued the wing halfes together and put in the servo for the flaps.

With the combination of links as shown it is possible to set up everything the user wants. The connection to the flaps itself is done with a piano wire in Z shape, running in an aluminium tube. This is written in a few seconds - but it took a few hours to make it...

 

RDS system: When I was writing further up that there is all the space needed I was not totally correct - there was enough space for the servo but it was very close with the brass disc - so I had to grind out the ply lid and the ply support below the servo to avoid touching with the disc.

Here you can see the servo in its little "cage", it is held in position only by the lid of the hatch.

So everything is hidden now

This is the view from the top of the wing.

 

I wonder what the weight of the model will be when finished....But this will take some time. I have only one more evening before my project goes into winter break....

[Danny Fenton]

Lovely work  You have done the flaps in the same way as I am going to do the Spitfire. I was wondering how to split the linkage, you double layer of ball links is a nice solution, I shall borrow that if you don't mind?

 

Cheers

Danny

[Vecchio Austriaco]

I am happy if my ideas work  - feel free to copy. The double ball ink was necessary as the arms of the Z wire are not bent exactly 90 deg - and now - beeing in the model it is impossible to bend them without ruining something. So when I open the flaps the wires run slightliy apart from each other. The second advantage is that ball links have no play. Use a metal servo arm (or a strong plastic one)  to avoid that the arm bends to one side if one of the flaps is stiffer than the other.

The advantage of the arrangement as shown is that you have the possibility to change the trim but also the throw by moving the point where you fix the link to the piano wire.

 

 

[Danny Fenton]

Okay I will take your advice and ensure the arm is stiff. The reason I need to do something similar is as you say the arms move closer together and further apart at the ends of travel. Your solution will work well, thanks.

 

Cheers

Danny

[Vecchio Austriaco]

Just to let you know that I didn't fall into winter hibernation a small update. I was 3 weeks busy with removal issues (390 items or 65m3 of stuff) and brought finally an estate full of stuff which I didn't want to put into storage (75% model related ) over to my UK flat. Now I have all my tools, and therefore I should be even more efficient. But it took another week to find space in my flat to put away all my tools and the 2 additional aeroplanes and last but not least my part finished 2m Extra...

 

So. What is the progress on the Bonanza?

 

I did put on the main landing gear, and gave the plane a slight inclination (front up) as I have read in other threads about the Bonanza that take off was a problem - the plane sticks to the ground. As I made a similar experience when flying with skis - you can wizz around with 40km an hour put the blooming plane doesn't take off....I gave it 5degrees. Also I left the landing gear rather high as the MKMAA has a grass strip and I want some clearance between prop and ground. Clearance is now abot 3cm.

 

The wheels are fixed just provisional, but having the lathe moved over I will make some proper accessories when I can find the time.

 

As you can see I played also with the engine, I gave it 1,5degree side and downthrust.

By the way - putting the engine iinto its position when the cowl elements are in place is a nightmare. There are 3mm of gap between the engine and the cowl, so you cannot access the back end of the engine. It always turns away if you try to put a scew into its place. It took me quite a while to put the first screw in (All holes drilled and engine test fitted before glueing the cowl parts on...but I took the engine out to avoid glue running into it)

 

Even there is a lot of space in the fuselage it is not easy to find a place for the receiver - which should be rather in the front. With all the extra wiring and pneumatic tubes space is going to be a problem.

[Danny Fenton]

Looks great VA, how is the weight working out and more importantly the c of g?

 

Cheers

Danny

[Erfolg]

I am not sure if the model is tiny or there is a lot of gear placed in a small volume.

 

The construction also seems very complex. The build quality looks excellent. Of course i will not allow such images influence my rudimentary build quality and ethos.

 

Well done.

[Vecchio Austriaco]

No visible progress from yesterdays work. I just played around with positioning the different items and the light system. The resistors I have purchased to reduce the current were much too conservative. I draw only 25mA instead of the allowed 120mA. So I have to try to find some resistors here for replacement. If somebody could give me hint where to find electronic components in small quantities in the UK it would be grat.

 

Erfolg: The model has a wingspan of 1080mm (or 41" for the guys prefering imperial). So it is not too big. There is a lot of space in the cockpit - but I would like to make it a bit scale so I will not use this space. And there is also some space below - but the access to this area is bad. So to insert the receiver into the space above the wing you have to carefully think and try how to squeeze it in.

 

About weight: As I brought all tools over i have now also my wifes old digital kichen scales. They show 1050g with all stuff which should go in. In any case I have to add a little weight for the Oracover. This trial was done with a 2200mAh 30C battery. I could save some 50g using an 1800mAh one.

 

The plan says 800g flying weight - I don't know what they left out

 

COG: looks ok, It is more or less where it should be. But tail servos are still not in, so I think it will move back a bit. A bit too eary to say more.

[Vecchio Austriaco]

Components: Found a Maplin store 5 minutes from my office....

[Pat (rActive) Harbord]

Looking good, you solution to the flap linkage is excellent, where can I find these ball links? Can you post a more close-up photo so I can see exactly how you have it set up? Currently I have used fairly flexible wire and shrink tube to form the joint (not great, but works).

 

I can't imagine how they got the prototype down to 800g my flying weight is now 940g since retro fitting the flaps.

[Vecchio Austriaco]

The ball links are from Als Hobbies but I used similar ones in Italy in the past - means they should be easy to find. The picture comes tomorrow.

Happy to hear that also your plane is somehow "overweighted" - I have extra weight coming from the wiring and the control box for the light system. Also I use a slightly bigger engine if I remember right - Turnigy C3530-1100. This is the maximal size that fits without alteration of the cowl.

[Vecchio Austriaco]

Here is the update – sorry for taking rather long but I was busy. First of all the close ups of the flap pushrod and its components. You will find those at most of the main street shops,

 

 

What else has been done? I tried to proceed with the wing, as there were too many cables hanging out. I tried to arrange them as nice as possible, it is still a mess I have to say. If you ask yourself what is behind the blue shrink tube – have a look. There are the resistors to limit the current for the lights. Why 2? As I didn’t get the right power rating I used 2 of half value in series to disperse the heat. (The landing light leds draw 150mA – so a small 1/8 W resistor is already getting hot)

 

Landing lights: I just used a piece of metal coated polystyrene with a 5mm hole in it and some lexan foil on top. It should be visible also in bright daylight, looking into the beam from short distance is rather dangerous.

Finally I could close the planking and make the wheel wells. Now having my lathe again I made a brass tube for every wheel to be sure they are running nicely. Also I made some aluminium washers to keep the wheels in position.

I played also with the retract system, the servo is finally in place and working – but during testing my bicycle pump gave up. Now it is time to buy something more serious.

Pictures of the servo moving the retract valve will follow – whe I fit the switch. What switch? The electronics from smservices are nice but heavy – so I decided to realize the landing light with a switch which is operated by the piston of the valve. Weighs practically nothing.

One thing which makes me some stomach ache is the front wheel – it could be controlled – but I do not have enough channels on my radio. If the model would have a normal cross or T tail it would not be a problem – just one servo to connect to the rudder with a Y cable. But with a V-tail I would need a mixer which produces a pure rudder signal – otherwise the plane would taxi around the corner if I pull the elevator…

 

In any case – I would like to purchase the Spektrum 10 channel radio when on the market (and not too expensive… – and until then the plane has to fly with a fixed front wheel.

 

I started also cutting the cabin cover into shape – the cabin roof is quite wavy – but this is an aeroplane from the 50^th so who cares….

 

The black 80p spinner will be replaced with something more suitable – if I find something matching.

[Pat (rActive) Harbord]

Looking good, thanks for the photo of the flap linkage, must sort mine permanently in the same way.

[Erfolg]

The weight as stated for yourself is most commendable, particularly when retracts and drive are included.

 

I have wittered on the same theme before, but always think it is worth repeating. Many WW2 aircraft seemed to be forged by the hammer and anvil of Thor. Many private mass market post war light aircraft look that they are the product of "kit car" builders, with their masses of round headed pop rivets and folded metal for both form and increasing rigidity.

 

So I totally agree with your comments on the canopy.

 

I am amassed at how much you have achieved with so little in the way of facilities.

 

Where you do your sanding? as i cannot imagine that going outside is very convenient.

 

Well done

[Vecchio Austriaco]

There is still some sanding to be done (cowl and fuselage cover) and normally I do it in the lounge (or bedroom, as you want to name it in a studio...) I have to clean it myself so I know what follows a sanding session. The lathe I run in the kitchen-the floor there is more forgiving then the carpet in the bedroom....

 

Actually I have a garden - but as you said it - its too cold. The only time I go out doing something for the hobby is to go flying. Like yesterday - the thermometer showed 3deg C but there was a constant breeze which made it terrible. I emptied 5 batteries on my edge and 2 on my Sukhoi and after that I had difficuties in opening the screws to take the planes apart as the fingers where not moving....