Archive for March, 2011


Hello!

I will continue my mod now. Last time I made preparations, cut out control surfaces and stiffened up structure. Now we shall insert some servos and test them out. Very exciting 🙂

First I built a professional-grade servo testing facility. As you can see I use a linear and some tape to fix the servos. I put some servo horns and fired up my 25A ESC with help of my slightly puffed LiPo and my shiny new Turnigy 9X v2 radio set. Now we’re talking. I see a video coming 🙂

I tried to set up my servos as much as possible, the final settings will be done in the plane.

I cut out a hole for the servo. Best is to first locate your servo, then draw the outline, then verify once more and then cut. When you have the outline cut you can cut thin slices within the contour and then “dig” them out carefully. If you are patient you can progress with slices all the way to the other side of servo “shadow”.

I measured 40 mm from wing joiner cavity.

And 200 mm from true center (!) of wings.

I joined the two wings and connected my servos to the receiver. I did not really set up anything yet, you should consider this as a functional test. Not even reversing is set yet.

Next I have to finalize the wings and then continue with rest of the plane. Soon it will take shape.

Best regards,

Sir Crash a Lot

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Hello!

Earlier I promised that I will do an aileron mod on my Easystar. After some long preparations here it comes.

I read a good description of how you should do this, please find it here. I followed this tutorial with some deviations of course. I did not straighten out the wings and some of the dimensions I did not follow either.

First I cut out the ailerons.

Then I made another deviation, instead of 400 mm length I took only 350 mm.

Deviation again: I planned to use real hinges instead of having clear tape as a hinge. This meant that I had a lot more to do. I had to have double V-shape cuts (half-half) on both wing and aileron. This is difficult to do, next time I think I will just have good quality clear tape and simple V-shape all the way through.

I added carbon-fibre stiffening reinforcement on aileron. This really helps, became really stiff. Glued with epoxy, it is a joy to use epoxy by-the-way. I was afraid of it in the beginning, no worries any more.

I put my hinges in middle. Glued them carefully, wiped off the excess. Tried to not get glue in the hinge mechanism.

Depth-of-field is shallow, this happens if you try to do macro with a single lens reflex camera and no special macro lens. I like this effect 🙂

What is a question yet to me is air flow. If you read the tutorial from Ian Puller (linked in beginning and here even) you can see his concern about air flow over the hinges. In my case there is a terribly ugly cut and a rather big gap there. If I have used tape as hinge I could benefit of nice airflow above wings.

Maybe on next plane I will not use hinges, we shall see how these perform.

It is important to have a gap on both sides, so your aileron might not jam.

I also made the stiffening on wings, as RC Explorer recommended.

10 mm carbon-fibre strip glued in the wing, flush with wing joiner surface. This stiffens up the wing quite nice.

The piece of Kleenex was left there since I used it for holding the carbon-fibre strip during 6 minutes curing time. It got glued but it is better than if my finger got glued there.

This was the first step of aileron mod. Next I will insert servos and connect them to ailerons.

Best regards,

Sir Crash a Lot

Hello!

I bought a new radio, great news. Currently I have a super-cheap 2.4 GHz radio from Hobbycity, the one that does not feature any menu system. You can program it from computer with USB cable and a dedicated software. It works fine but as it only features 6 channels I felt the need to have something bigger and better for FPV. I plan to use OSD and pan/tilt camera so 6 channels will not work.

I really liked the specs of some higher grade radios, like the Futaba T8FG. Quite nice transmitter, you can see the specs here. It is quite pricy to my budget right now, it remains on my dream list.

A colleague was selling his Turnigy 9X radio, this unit is in my price range, so I signaled my interest and asked him to consider me as a possible buyer. We made the deal and now I am a happy owner of an almost unused Turnigy 9X v2 radio transmitter. The v2 is important, this is a revised upgrade of the first 9X. It has 8 model memories instead of 5 (good feature) and can handle expo and dual rates without workaround solutions. V1 had problems with these settings. Not a major flaw for me, I think I will never use expo.

The radio is modified buy the first owner. He put some glue on the buzzer, this is good actually. It beeps at amazingly high volume by default. Either you tune it electronically (with some resistance) or you use physical methods.

I got 4 pieces of receivers with it, I think this will do for some years. I am not having more models than one right now. I am quite future-proof now.

I will do one mod on it, attach a transmitter Li-Po later. It runs on AA batteries (8 pieces). I have very good batteries for my Lama v3 transmitter, so this is not a hurry.

I was eager to try out my new radio, so I made some servo test. Works like a bliss.

I really like this radio, great price/performance ratio. Hard to beat. The menu system is to get used to, I don’t understand it yet, however I shall dig into the manual and comprehend it prior ti flying my plane. That is good to do, otherwise I get confused with all the switches. Quite capable unit this is.

As I managed to bind one receiver to the transmitter I continued with balancing my propeller. I took a screwdriver and balanced it on the edge of kitchen table. Rather unprofessional but works at some extent. I will never reach super accuracy with this method but helps a lot.

It turned out so that I had to cut away quite a lot from my propeller, you can see that later in the clip.

I made a motor test with the balanced propeller. My experienced colleague helped me to drill my wood propeller to right diameter, we even refit the plastic one. I learned the correct way to mount it, the text on the propeller shall point in the direction of flight. Good to know.

Please see my recording of balancing and motor test.

I was not sure if I shall teach the ESC to sense full throttle setting so I tried to do this routine. I pulled full throttle on the radio, switched in on and connected battery on ESC. Then I pulled down the throttle stick to zero gently.

What I thought that will happen is the ESC learns full throttle setting and will reset itself. Well, something else happened. The motor went up to full speed as I gently pulled the stick down to zero and I got rather surprised. If I weren’t Sir Crash a Lot I could even tell that I got almost scared. The motor revved up to full thrust and blowed my magnetic shopping list off from the fridge door. And knocked over the kitchen chair so it leaned against kitchen table.

As I placed then close to each other it did not tip over fully. And as I hooked around the motor several times in both diagonals with tape it did not get loose. However it wasn’t so clever thing to do, I think setting full throttle setting is better to do without the motor coupled to the ESC.

I do not have recording of that incident, the rest of the motor test is captured.

Next thing will be to start to build the plane. I will need to read through the manual and then “Get On With It!” (Monty Python excerpt).

Best regards,

Sir Crash a Lot

Hello!

I received my parts recently and started to build my very first RC airplane. First step was to do some soldering (or “soddering” if you read from USA).

I used to play a lot with soldering iron as a kid and was confident that soldering itself is going to be fairly easy. During my helicopter build I learned quickly that playing with soldering iron does not necessary mean that I get proficient in soldering, more like wasting solder wire. This time I was way better than with helicopter, although I wouldn’t consider myself any good with soldering yet. As always if you solder take precautions, don’t burn yourself, nor take risk of fire. Never leave soldering iron unattended. Safety first.

I could share some pictures of what I did this time. Basically I soldered my 25A ESC, since it comes with bare wires. This is actually good so, I am happier to do a perfect soldering myself (ha-ha) than rely on some questionable quality from factory. This way I can tell that I made it wrong 🙂

Preparing wire lead:

Preparing XT60 connector:

Using 3rd hand tool for soldering together XT60 and wire:

Not forgetting heat shrink tube!

Beautiful soldering done on connector:

Soldering other lead as well:

Soldering motor connector (heat shrink prepared)

Comparison of 40A and 25A ESC. Since this ESC will sit in air flow a slimmer design is welcome. 25A has the advantage here:

Notice how slim 25A is compared to 40A. A save a lot of drag here:

Motor came with connectors soldered already, no need to do it:

Read manual carefully and setting ESC with programming card:

A VERY incorrect way of installing propeller, this is only meant for trying out the motor. Do NOT install propeller this way!

Again, a very incorrect way of attaching your motor to kitchen chair. Do NOT attempt this at home.

I was very keen to try out my new motor along with this 6×4″ propeller. I always tend to write 15×10, but it is in centimeters. Approximately 15 cm in diameter it is, standard designation is however 6×4″ to be exact.

I attached my motor to kitchen chair, made several loops of tape around in one diagonal, then switched and looped it around in other diagonal. It sat rather good there, checked if I have good clearance from propeller. Then I asked my wife to not come in our kitchen until I tell her so even if the propeller gets loose she does not get hurt. I tightened propeller adapter earlier.

I took some distance, connected ESC to motor, turned on radio then connected battery to ESC. Self test ran through fine and then I could rev it up.

Since I never balanced the propeller (don’t know yet how to do) it is unbalanced. My experienced colleague could tell from the sound of it (!) that we have unbalanced load case. I made two silly things here:

– unbalanced propeller

– propeller is not pushed all the way to the bottom of adapter

I will correct these issues later, for the sake of this brief test I used it wrongly anyway. If you build you model don’t do so, balance it well and mount propeller as it should be (to the bottom of adapter).

I did not rev it up more than half throttle, in kitchen it was plenty loud and almost frightening. Since I am a very brave man (I am Sir Crash a Lot after all!)  I was not frightened of course, but I could think that anyone not so brave as me could get frightened indeed 🙂

A note of safety here. I was well clear of propeller. I had every screw tightened. I did not have anybody in kitchen during recording. I used common sense. Do not attempt this unless you really know what you are doing. Even at half throttle you get awfully high RPM levels. This is no toy, serious injury can occur if you do something silly.

And now the film of motor test:

As next I will need to balance my propeller, mount it properly and continue with build. Very exciting, I plan to have it ready for the good weather.

Best regards,

Sir Crash a Lot

 

Hello!

I ordered some more parts on last day of February, picked them up on 10th of March. Chinese New Year celebrations took their toll, at this time there is a huge pile of packages that get sent from Hong Kong. Due to this my package got quite late. No big issue, I did not have any hurry.

Earlier I made a list of what I ordered, now you can see some pictures.

The box itself was surprisingly small, I think that Hobbycity employs some black belt grade packaging staff. The box wasn’t even fully filled, they could place some dampening air bubble packs on top of my parts. 5 stars for safety.

There is such a huge amount of unpacking or “unboxing” videos on Youtube that I was simply forced to do one myself. I have very poor camera equipment yet, no dedicated lightning for recordings either, so I tried to cure these flaws with creativity. I managed like this:

If you watch it you might understand that most probably this is going to be my first and last unboxing video 🙂

Back to the important part, pictures of shiny new electronics and build material. Shrink tubes and motor:

Wooden prop, servo wire and some linkages:

Wires and plastic prop:

ESC, ESC programming card, propeller bracket, servo:

Finally a partially assembled propeller and motor along with my hand for size reference (I can do CTRL+F8 with one hand on a standard keyboard). Prop is 15 cm diameter, quite big propeller. The wooden one looks amazingly nice.

I could not fit the wood one yet, the hole is too tight. I learned from my experienced colleague that you can drill it up to bigger diameter, he even has a handy tool for this. Will take it to the office on Monday and we try to fit it. Very exciting, it would be great to have the wooden prop for start already. Looks so classic in real life, even if this sounds silly in case of a foam plane 🙂

I am very happy with my parts, try to start building this weekend. Will get back with more details as I progress with the build.

Best regards,

Sir Crash a Lot