Tuesday, December 22, 2015

Falcon's Perfect Landing!

I must say while I am a big sci-fi fan (which is odd to say, considering I actually cannot be bothered to go watch the new star wars), I'm not really that into real space flight, though I do read up on them and get excited when they pop up on my news feed. Anyways, this is just superb. Beautiful. Go SpaceX!

Side note: I've always wondered what "lox" was in 2001: A space odyssey. I've always wondered why the heck they had salmon in the emergency rations. Was this a some futuristic British thing? Finally, thanks to this video, it has been answered. It also proves how much of a space nerd I am not!

Sunday, December 20, 2015

Z3 Day 2. I'm lovin' it.

I don't get it. Comparing the Sony Z3 to the Samsung S6, I can't fathom why I'm loving the Z3 so much more! I think this is the 2nd android device I really like, the first of which is the Xperia ray. Never really got into the Nexus 4, and the android tablets I have/had? Blargh. No thanks. IOS ftw there.

To me, Z3 vs S6:
The ergonomics on the Z3 are poorer.
The hardware feels cheaper.
The screen just does not compare at all.
The camera is pretty crap compared to the S6.
The charger that came with the phone evidently doesn't supply enough current to charge the phone (I have to use my Nexus 4's charger lol)
Opening the waterproof flaps to charge the phone is fiddly.
Instructions on how to insert the sim card are practically non-existent.
The torchlight is an epic fail.

But somehow, the UI and feel of the phone is just right. I really like the included widgets, they just align on the home screen just right. THE BACKGROUND SCROLLS! And best of all, I didn't have to waste time "rooting" the phone or going through the app store to find replacements. It just frakkin' works!

So glad the S6 is sold. Hope the new owner likes it :)

Saturday, December 19, 2015

Goodbye S6, Hello Z3

So after a week of using the S6, I decided that I really do not like it, and put it on ebay, and got a Sony Z3 instead. Originally, I wanted to get the Z3 Compact for the size, but the prices on ebay had the Z3 for cheaper, so hey! Buuuuuy. Z5 was out of the run - price wise, and I didn't want something with a processor that's mainly for marketing to compete against newer iphones.

In the meantime, I've been using my alarm clock, aka a used Iphone 5S for my main phone. I was very surprised it actually worked since I've never put a sim card in it. Heck, it somehow even got a lte signal. Samsung, Sony, LG, still haven't got a clue how to include good alarm tones like Apple. 

Haven't used IOS since IOS 1 on the very first iphone, and it was not as annoying as I remembered. If not for the weird love/hate relationship I have with Itunes, I would probably use an iphone, but I really, really like plugging in a usb cable and downloading my food photos which I never upload. So there.

Well first up, things about the Z3 that I liked:
- Alarm has adjustable snooze (yesssss!)
- Adjustable size clock widget (much win!!!!)
- Background now scrolls as I scroll through the home screens (YEAAAAH!)
- The "old school", "dated","bloated" Xperia UI that reviewers like to mention, I found very nice to use, not the gelded annoyance that is TouchWiz.

WIN! It does everything I want that the S6 does not!

That said, there are things about it that I think could be better:
- Screen: S6 is the winner by far, it's damned good. The iphone 5s arguably has a better screen than the Z3, but it's not something that's heads and shoulders better, like the S6's screen.
- Z3's Torchlight is a weak, pitiful thing. The S6 and 5S have kickarse torchlights.
- Ergonomics: The S6 my personal winner here. The S6's power button is exactly where my thumb falls, and the volume controls balance well on the other side to be managed by my index and middle fingers. The Iphone 5S's power button is my main nitpick. The 4S's power button is fine where it is, due to the shorter phone. The 5S requires more leverage to push. The Z3 has the power button where my thumb falls, but it's rather small. Also, the volume controls are below the power button, I find my finger movements rather restricted, attempting to change the volume.

I must say, I do miss having a physical switch for the sound/vibration like the Iphone, but with my day job, it's rare I need to quickly put my mobile to silent mode.

Now apps wise, I appeared to have bought a phone for UK's EE Carrier. There are some EE apps, which I haven't yet gone through to disable. Lots of Amazon apps, which I've gone through and disabled (can't be removed.) Several sony apps, but I'm a sony fanboy for now, so I'm just leaving them there for the time being.

Now I have to compare the Kindle app on IOS vs Android. IOS's version of the kindle app definitely just feels better to use. No irritating "please re-download this book to read it" crap. The Kindle app on the Z3 already gets this crappy warning the first time I loaded it up. Grrr.

Oddly enough, there is no notepad or to-do list on the Z3 (why, Sony, why?!). Had to use the app store. Blargh.

Other things is the Z3's screen is a super finger oil magnet. The S6's screen was somewhat better, but the ios screens in my experience can handle the oil so much better.

The biggest thing I will miss from using an Iphone is Siri. I like that I can ask her to (I've configured my Siri to speak with a sexy british accent, btw) turn on my 8am alarm, and she will ask me, which 8am alarm to turn on. Now that's damned useful. I can even get her to turn on *and off* timers.

Google now can do it all (and google now can actually turn on the torchlight, which siri can't for some reason), but it's hit and miss. I had to try several times just to get Google Now to set a 15 minute timer, and I have given up trying to use the voice commands to get it to clear the timer as it just brings up timer suggestions in a google search >.>

Guess you can't have anything.

The camera doesn't seem to be as solid as the S6 or Iphone 5s's, but that's through the live view. Lots of bloom, and not as much manual control as the S6's camera. I've got to test it more, but the S6's camera is just *that good*. Iphone 5s _appears_ great, but as mentioned, I have zero interest in pulling up itunes just to download photos. BLARGH.

Now with the Iphone 5S, I'm able to get almost 4 days of battery life with my usage patterns, though I usually charge it on the 3rd day before bed. It's a nice quick charge too, about 2 hours, on some random usb charger. The S6 charges just as fast with its QuickCharge 2.0, gonna miss that. The Z3 is appearing to take *forever* to charge up, so we'll see. What I'm looking forward to is the "stamina" modes that promise a really long battery life. If it can give me 4-5 days between charges, it'll be great!

Sunday, November 22, 2015

Got a Galaxy S6... mixed feelings

Somehow or other, I came into a small sum of money, and as luck would have it, my Nexus 4 is having some weird issues like causing the charger to spark (!!!!) when charging, so I thought it was time to get a new phone.

I really wanted to get a Sony Xperia Z5 or the Z5 compact as I've had my best android experience from Sony's interfaces, but not only is it rather expensive, the many reports of the overheating of the Snapdragon chips just do not endear it to me. Nexus 5x was another option, but somehow I was not enamoured to its design. Enter the Galaxy S6. Originally, I was going to get the Sony Xperia M4, but due to events, suddenly had the budget to consider a "flagship" phone, and the S6 was one of them.

I've never really liked the touchwiz interface, and it's quite horrendous on my Galaxy Tab 3. A quick test at the mobile phone kiosk told a different story. The S6's interface is now much more to my taste, and it felt _really_ nice in my hands.

So, having the budget for a top-of-the-line phone (the S6 edge I thought was too flashy, iphone 6 for some reason turns me off.  LG G4 - curved screen I was uncertain of its suitability for VR use), I decided to get the S6. Unfortunately, here in Canada it's not quite that simple. Visiting the virgin mobile shop, I was told that I couldn't buy the phone outright (?!) even though it was priced at the stall. I had to get on one of the month-to-month plans in order to buy the phone. Several phone vendors I visited told me the same thing. No monthly contract, no new phone.


I really didn't want a more expensive contract as I rarely use more than a few minutes of talk time a month, so I went online and found a S6 for the same price on amazon, and, it was unlocked. Boom!

I must say it's a very nice device, much lighter than I though, and the power/volume buttons are positioned perfectly. The fingerprint unlocking is great! Doesn't always work, but a slight shift usually gets it right.

Lots of crappy apps were installed, thankfully most could be uninstalled or disabled.

Now while reviews online are falling over how amazing the screen is, I really can't say it's that big a deal for me. It's good, it's sharp and can get bloody bright, but honestly, unless you've got the eyesight of an eagle or something, I really can't say the super high res screen is useful for day to day use. The only real reason I can see the screen being useful is for use with VR applications with the Gear VR or google cardboard.

The 720p screen on my Nexus 4 definitely shows the pixels up quite clearly when used for VR. However for what I use the phone mostly for, like using the Kindle App, I honestly can't say the S6 has a definite advantage over the Nexus 4 - apart from the larger screen size.

Had to use the phone app, and I must say, it's a disappointment as usual. Much prefer the phone app on my iphone4s. I mean sure, I could probably download another phone app, but given that I use my phones mainly as very expensive alarm clocks, I just suck it up.

Speedwise, the S6 is a speed demon. I was testing the Unity 5 PBR workflow, and my test scene on the nexus 4 was averaging just over 30fps. The S6, was clocking in roughly double the fps... but at QHD resolution. Totally mindblown. If I were to render-to-texture the test scene at 720p to match the Nexus 4, it'd hit 200fps, probably.

Now as mentioned above, I use my phones mainly as very expensive alarm clocks. So, the alarm function is rather important. One again, the Iphone 4s takes the cake as my primary alarm, and the S6 will get relegated to my secondary backup.

The S6 has the exact same features I need from the iphone, but the snooze function (oh I snooze much) has a quirk that annoys me - to snooze the alarm, I needed to press a very small, specific area on the screen (?!). In addition, it only snoozes 3 times before it turns off for some reason.

The Iphone4, to snooze, I just tap the screen (which I can do with my eyes closed!), to turn it off, I slide. Easy, and it works. WHY SAMSUNG YOU CUSTOMIZE IT SO!? Even the Nexus 4's snooze was so much better >.> I actually spent some time browsing the android app store for a clock app, but gave up as there were soooo many choices. Time better spent drinking tea.

Other smaller nitpicky reasons why I got an S6: The android phones prior to this, the Xperia Ray and Nexus 4 had a very nice clock that was rather customizable, and doubled as the alarm app. I like those clocks as they are nicely offset just to the right of the screen. Unlike the iphone, which has the damned clock right in the damned middle of the screen, which I think looks horrendous. The S6 unfortunately, I can't seem to adjust the clock the same way :( Once again, visited the app store and OMG, too many clock apps. I'd much rather clean my bathroom than look at those apps.

So yeah, winners here are: Nexus 4 and Xperia ray for clocks that I like. I actually went so far as to install the Google Now Launcher, but sadly, the clock just wasn't the same.

My wallpapers also don't work very well now. On the Xperia Ray and Nexus 4, when I switched between the.... desktops of the phone, the background would scroll to follow. Not on the S6! OMG WHY SAMSUNG?! The Google Now Launcher *does* scroll the background, but not in the same way as my older phones.

For example, my Nexus 4/Xperia Ray has a middle screen which is the home screen, and I had two additional screens on either side of it. The Google Now Launcher appears to have the main screen on the left, and I could only move to desktops on the right.For the wallpapers I enjoy, this means that I have to have the subject on the left, not in the center.

I promptly uninstalled it and went back to Touchwiz, because, I can legitimately complain about touchwiz, if I actually use it. 

One thing I'm really looking forward to the S6 is the ultra power saving mode. I'm rather sick of having to carry a battery to charge my Nexus 4 as it's battery's getting quite old, and lately the battery pack can't even charge it up to more than 60% before it runs out of juice so...

Oh yes, the camera app. I think this camera app is my favourite to date. Very minimalistic layout, AE compensation is right up front without needing to go into a menu, and the best part: Double pressing the home button brings up the camera app. The app launches in perhaps a second and a half. Really really love it.

Of course, I have to complain about the camera. I wish they didn't put in a 16 megapixel sensor. When I saw the resolution, it's such a joke - it's even higher-rezzed than my dslr. But we all know who will kick butt when it comes down to quality. I wish Samsung had it around oh... 5 megapixels? For me anyways, if I do use my camera to upload stuff, it's only to facebook and maybe this blog. Which I'd downrez to fit the page.

But all in all, I'm honestly looking forward to using the phone. The bigger screen is nice for reading, and.... hmm.... well I dunno. I have this feeling I really should have bought the Xperia M4 and call it done. I don't subscribe to the mobile lifestyle, and this phone is honestly overkill for my needs. One of the excuses I used to justify this purchase is Gear VR, and I can tell you honestly it's very unlikely I'll buy into it. But we'll see. Oh well XD

Thursday, November 12, 2015

DIY Canard Airframe 08

Woo! The wings are all done, and I've completed my glide testing too! The Canard CG Calculator I'm using is rather spot on, at least for the glide testing. I added a few more grams of weight up front though and the glide improved a fair bit.

Right now, with the weight it's up to about 380g, frankly quite surprised it's able to glide as far as it did (15 meters? 20? ).

Actually, when I first did the test, I was just throwing it, and it just kind of tilted to one side and nosed into the ground. Only when I ran a few steps before throwing, did it do a nice glide.

Next I'm going to have to see what the current CG is, the begin installing the electronics. From what I gather, the battery will definitely be moving up close to the nose. Hopefully I can get the cg right purely from moving the battery.

Monday, November 09, 2015

DIY Canard Airframe 07

The 3 sections have been connected, and the wings are being constructed. The front canard didn't take too long, just a single 40cm wide kfm3 section. The rear section though, is made up of two pieces, and has the carbon fiber rod going between them to strengthen the wing.

Thursday, November 05, 2015

DIY Canard Airframe 06

The 3 different sections of the fuselage are now ready to be connected.

From what I see, this design is really really weak. The section housing the motor is actually not bad, takes torsional forces well as there is not only the motor plate holding it up, but another piece connecting the parallel sides to give it rigidity.

Not so with the front two pieces. Individually, I think they will stand up to the rigors of compression and tension in flight. However, torsionally, there is nothing to resist such forces. There will be a layer of wood used to connect the sections, but again these are not that strong against torsional forces.

What I do have, are rectangular pieces that fit in during the gluing process to make sure everything is square. I intend to drill out the center of these pieces to allow wires and connectors to go through, then glue them into place inside the frame to provide some torsional resistance.

This has been a good learning experience so far. Will defo have to keep this in mind for future designs! The fuselage in the photo above is also resting on the left/right sections of the main wing.

Monday, November 02, 2015

DIY Canard Airframe 05

Woooot got the airframe laser cut properly this time round! This time I figured out the settings to get the pdf to import and be properly converted to vector line art. Things went smoothly after that, took just slightly over an hour to get all the pieces cut. Total time on the laser was 13.5 minutes, and I was charged just over 23cad for it (1.50 cad/min, rounded up to nearest minute).

The photo above is the properly sized laser cut out, versus the 88.8% scaled version. It's actually a rather big difference in real life, I'm now wondering if it's really able to fly! Weight of the chassis alone is 185g, and that's without the square dowels to provide extra torsional support.

To make sure that things stay square, I've cut out some square temporary supports that fit inside the fuselage while it dries. So far, things _appear_ to be going well, apart from the weight. I've also cut out the main wing from the DTF, but I'm going to take this build slow, as Vancouver's suddenly entered the rainy season. Rain started around 10am, and it was still coming down lightly when I got home in the evening. Even if I finished this build early, I will still need to get a calm-ish day to maiden her.

Saturday, October 31, 2015

DIY Canard Airframe 04

Woot! First time out with the laser cutter. Unfortunately, the holes that I meant for the bracing to go through were too small for the piece of wood meant to go through it... looks like I'm going to have to make another trip down. If not, it was a very successful run.


I spoke to hastly. The holes were too small, because the entire object was printed at about 88.8% of full scale! Darn it. I was wondering why the battery fit so snugly when I had planned for lots of space. Only then did I measure it, and realized that there was a size discrepancy.

If so, then the weight for the full fuselage will far surpass my original design estimates, and if I continue down this path, will have an airframe with much higher wing loading.

I need to think how to proceed. Very likely I will just proceed, as I do hope to learn more about creating a canard.

The original idea behind the wood frame, is to have a strong underlying structure, as the foam weakens significantly with holes cut into it.

Let us ponder.

Edit 2:
Didn't want to make a new post. I stuck the whole thing together with Titebond III .As I didn't have any clamps, I just relied on the thick rubber bands used to hold down the wing to hold the pieces together.

Titebond is a pleasure to work with, while the working time _could_ be longer, it was good enough for the few pieces I had to cludge together. In addition, it clean up with water! Some people have mentioned that it doesn't sand as well as Titebond III, but I don't think I will need to sand much as it just wipes away with a damp paper towel. And it washes off in the toilet, easy!

The strength of the glue is extremely impressive. I did some test with some waste plywood pieces and the glue of the veneers gave way before the glue bond. That's extremely impressive. The assembled fuselage otoh feels extremely rigid, and that's before I even put in my extra bracing.

I think I will just go ahead with the build. My motor is theoretically able to give about 600g of thrust with an APC 8x4E prop, and if the aircraft comes in about 800g, the thrust to weight ration _should_ be fine.

In the unlikely event that I would need more thrust, swapping to a 9x3.8SF will give over 800g of thrust, at the expense of flight time. In my limited experience so far, all my designs have take off at perhaps 60-70% on the throttle, and I can usually fly around half throttle, so it's very likely I will have enough thrust on just the 8x4E.

Quite excited to see how this build goes, but I am also very tired as I could not sleep well last night, kept waking up ever so often. Argh.

Friday, October 30, 2015

DIY Canard Airframe 03

Laser cutting this design tomorrow :3

After some thought, I decided to just do the whole fuselage. Alot of the material will be removed anyways, and the estimated weight is about 130g? I've added lots of structure at the points between the 3 "pods" that should be rather strong.

The DTF will then be more of a protective surface and less a structural thing. Which is good, as I really have my doubts of the longevity of the fuselage once holes are cut for equipment.

Securing the battery down is another story that I'll think about later :)

Wednesday, October 28, 2015

Google Cardboard & Unity

Eh, got bored waiting my turn for the laser cutter. Only can get time on it on Friday. Sooooo bored!

Monday, October 26, 2015

DIY Canard Airframe 02

I was introduced to OnShape.com last week, and it's very eye opening to see how much can be done inside a browser! I'm really not sure how heavy they will weigh, and I haven't yet figured out how much offset I need to give the pieces to accommodate the laser's kerf.
I'll stew on this for a day or two, then hopefully I'll have some laser cut pieces later this week.

In other news, I have also been experimenting at making a strong fuselage out of DTF (Dollar Tree Foam/Readiboard). While Experimental Airlines has a great way of making a strong fuselage, I do not have the space nor tools to do what he does, so I've been trying out various ways to get a strong fuselage.

It seems like without cutting a hole in the fuselage (for putting in batteries etc), I could get a very very strong tube by leaving the paper on, and constructing a tube similar to the way Flitetest does their swappable power pods.

However, once a hole is cut, the structure weakens immensely, and you can see that it won't take torsional stress very well. For a canard planform that relies on a strong section connecting the front and back, I thought this would be a major weakpoint, something I had to figure out.

Experimental airlines deals with it using additional pieces of DTF to strengthen the walls, in additin to some bracing to keep the tube square, and this appears to work well. I tried this, and it didn't seem all that strong, when I realized... perhaps I was using the wrong kind of glue?

Being the need for strength, I pulled out Foam Tac as it's been very strong so far for bonding many many materials, and I really like that it's rather flexible after it's dried. It was this flexibility that I was concerned with, and did a quick test, gluing two pieces of DTF using Foam Tac and Gorilla Glue.

Gorilla Glue was the clear winner in this case, the material broke first before the joint - heck the joint is still there and everything around it is all broken up from my attempts to pull (shear) them apart.

Foam tac unfortunately didn't work as well in this test case; I pulled it apart really easily.

This further reinforces the need to test various adhesives in various contexts. Hot glue, for example, I haven't used much as it's so heavy, but perhaps it may prove to be an even stronger joint.

In addition, with wood-wood adhesive joints, there is still one glue type designed purely for wood that I haven't tested: Titebond III. This is supposed to be *the* ultimate wood-wood adhesive. Have to test this shortly.

Saturday, October 24, 2015

DIY Canard Airframe 01

After much calculating over the evenings this week, I decided to go back to my roots and build something simple. I really wanted to build a twin boom pusher airframe, but it seems like my ideas were very heavy and not good for flight.

I then watched some flite test and experimental airlines to get some ideas, and the Ansley Peace Drone came up, and I thought hey, why not, let's build something similar.

To keep things more on the lighter side of the spectrum, I'm going for a fuselage mainly made up of DTF (Dollar Tree Foam/Readiboard) , with plywood used to build sections that need to be rigid. For example, the motor mount.

VR Take 2 - it works!

So after returning the previous headset I got from amazon, I was still curious about bluetooth controllers for gaming, so read up around reviews and found this particular one that garnered good praise in its "Red Samurai" guise, as marketed by gamestop. Thankfully, it's a generic controller produced by Lemon, aka the S600. Browsed amazon.ca, and came across it under the Vigica brand, and decided to go for it.

It also came bundled with a vr headset for a few dollars more, so I thought, why not. Now when I first put this headset on, it worked pretty good! As good as the sunnypeak I tried, or even better, as I felt the rectangular screen was closer. For some reason, I took the phone out of its protective casing when testing. I then put it back into the protective casing before slotting it into the headset, and.... it made the experience very, very blurry. Seems like 1-2mm of distance between the screen and eyes is a BIG thing for VR this close.

The bluetooth controller also paired with little drama, though it's rather annoying to have to disable it as it appears to be a keyboard to the OS, thus the virtual on-screen keyboard does not show up. I haven't yet found any games I want to play with yet, but a gamepad testing app showed that all the buttons were working, which is well and good :)

Tuesday, October 20, 2015

VR - maybe not for me

Bought a pair of "3D VR Glasses" - basically a plastic version of google cardboard to give it a go. I've always regarded VR to be a gimmick - back in the 90s, I tried some "VR" googles for flight simulators and while it was cool, I really did not think it added anything. Of course, back in the day we were limited to low quality graphics and, IIRC, no head tracking. Tempered by my past experience, I never really got into the VR craze.

Skip forward to today, I gave it a go, but I think it's not for me. First, I think the glasses are probably not paired well to my vision. The image is only somewhat in focus, and I think it's the reason why I'm getting a mild headache.

The headtracking works great, if there's drift, I don't think its an issue at all.

My main issue is the apps for VR, while quite immersive, are just not my cup of tea at all. I think that for maximum use of VR, a dedicated game controller would be required. My version of google cardboard didn't have the magnetic button, so I have to use the included bluetooth controller. Which, unfortunately I can't seem to make it work in gamepad mode, only mouse mode (which works great!)

Probably gonna sell it soon. Urgh, have this pulsing headache on my temples. Graaah.


So I tried my friend's SunnyPeak VR Headset, and it works great! It came with resin lenses, and had the ability to change the interocular distance, and I had a much better time. The pictures were sharp, and I did not get any headaches. Seems like if you're nearsighted, not all work the same?

Saturday, October 17, 2015

RC Annular Wing

Getting back to this build! Finally decided to build it with rudder and elevator, instead of just rudder alone as I was planning to.

I've also no idea how things would work, I'm just going to use what I've learnt from building the 3 previous aircraft.

The only thing I know is where the approximate CG for this wing is, so I'm keeping the rear end as light as possible and keeping the weight up front. Hopefully it will all work out!

Monday, October 12, 2015

Kfm3 flying wing post-mortem

Maiden'd the Kfm3 flying wing this evening, and while it does fly, I really don't like the handling characteristics. It's rather pitch sensitive (expected) but for some reason it does not turn as well as I hope. It rolls well enough, but doesn't track as well as my Kfm4 wing. I wonder if it's because of the vertical stabilizers....

In addition, it has difficulty penetrating the wind. Even at full throttle it appears to move rather slowly. But more importantly, it's handling characteristics in a crosswind are rather poor. For some reason the Kfm4 wing dealt with it better. Maybe the wind was much stronger today.

Finally, the stick mount is just not working for this design. In order to have the thrust line aligned with the middle of the wing, the motor actually juts out under the wing. I've made a foam block to shield it, but hard landings can bend the mount.

In any case, I think I'm done with this experiment, and going to use what I've learnt so far to build another design. This one will be a swept wing with a pod, and the wing sweep will be a bit more than my first wing in order to make balancing the CG easier.

Sunday, October 11, 2015

Kfm3 Flying Wing Build Log 05

I was surprised when I received a small parcel today, containing the Cobra motor I ordered from the US last weekend. It's a Cobra 2204/58 1080Kv motor. This motor weighs almost half the weight of the Emax I was using, so I decided to rebuild a new, lighter weight pod. In doing so, the AUW of the wing is now 346 grams!!!

One advantage of having a pod (or fuselage) is that adjusting the CG should be much easier now - all I need to do is slide the battery forward and back, and use some foam spacers to take up the space.

On the flip side, there are now far more things to go wrong, and the wiring is more complicated. For example, the pod is attached to the wing with rubber bands. I've never crashed this airframe before, so I'm not sure how well it would take damage.

If the motor pod _does_ get destroyed though, it won't take too long to rebuild. In fact, I will probably have to create a new one when if I decide to put a camera and fpv gear on it.
The previous pod had the thrust line running more or less directly through the middle of the wing. In a sudden burst of randomness, I decided.... hey, let's try it with a high thrust line. And then I attached the motor with the mount flipped up.
 I can't wait to test her out on her maiden flight Sunday evening!

Saturday, October 10, 2015

Kfm3 Flying Wing Build Log 04

 Eh, didn't update the blog as I was struggling to figure out how to attach the pod to the wing.
I'd experimented with several ways of folding the tube after watching various vids only, and decided that I do not have the tools to do it, and came up with a sort of kludge solution that I _think_ kinda works.
So in the end, it started with the motor mount. It's basically a square basswood section sandwiched between two thin slices of basswood, with balsa filling in the gaps. I'm not sure how durable this will be, but it appears to be quite firm. Zipties are threaded through the wood section into the tube.

BBQ skewers are then pierced through and supported by hot glue from the outside. While this actually holds the wing very well - I'm rather surprised by how tight the wing is joined - I fear any crash will simply force the skewers backwards, tearing up the pod.

I'm also not exactly sure how I'm going to mount the electronics inside the pod, or how to strap the battery in. Oh well, I'll figure it out. This is what makes it fun anyways!

Thursday, October 08, 2015

Kfm3 Flying Wing Build Log 03

 Got the flying side of the wing taped, and the leading edge taped with heavier duty gorilla duct tape.
Folding the wing was much more difficult than I thought. I didn't have enough heavy objects to put pressure on the wing, so I placed what I had in the middle, and held down the left and right sides manually with pieces of unused foam.

Also, I got the pod built. It's slightly warped, and I'll probably cut off the warped area.
I've removed the electronics from the Kfm4 wing in preparation to fit them in tomorrow!

Wednesday, October 07, 2015

Kfm3 Flying Wing Build Log 02

I found some 5mm square basswood pieces, as well as some 3/16in wood dowels (about 5mm). The basswood was not as long as I hoped, while the dowels were longer than the span of the wing. I decided to take the longer dowels (I think they are pine) and fit them into the wing. The pine isn't as stiff as the basswood though, and I hope that for this small wing, it will be enough.

Tomorrow I'll be taping up the opposite side of the wing before I form the leading edge, and the pod has also been cut out from another sheet of DTF and ready for taping and forming too!

Tuesday, October 06, 2015

Kfm3 Flying Wing Build Log 01

So I need a new airframe. Spent some time ogling the beautiful projects on rcgroups, realize that I do not have the tools to get such cool builds going, and just decided to randomly design something.

After some thought, I've decided to build the following
- Kfm3 airfoil with 4:1 aspect ratio.
- A pod or fuselage of sorts below that will hold most of the electronics.

Easy yes?!

I quickly did some calculations on the flying wing calculator, and the CG is about... 4cm from the leading edge. I'm not sure what this plane is going to look like... but man, I gotta have some weight up front!

The Kfm3 airfoil is selected based on its heavy lift capabilities, as well as for ease of build. As the wing design I'm going with is totally rectangular, it is extremely easy to measure and cut out. Also, the ability to put in several spars (thinking of just 2 spars, really) to stiffen things up is really enticing.

Right now, I have a 9.5mmx9.5mm basswood stick, which I think may be too thick. So, I'm going to Michaels tomorrow to see if they have a 5mm square basswood stick, if not I'll just wing it and use the 9.5mm. It should prove superbly strong. I'll also have to be careful how to mount the servos, as I want them near the spar to properly support the wing and not allow the wing to lose its stiffness.

The pod below is not properly thought out yet, but it's going to be based on the pods seen on Experimental Airlines. Mine though, will be much smaller with a 4cm inner diameter - the widest thing I'm fitting into the wing is the battery, which is about 37mm wide. I was considering designing it to fit a gopro, but I'm not ready to send up a few hundred bucks into the air, experimental design or not!

Now in a previous post, I mentioned I wanted to have the motor up high, so as not to strike the ground. This may not be the best of ideas as the motor needs to go rather high, or, I need some long landing gear.

Given I'm not in the landing gear fan club thanks to the weight, and that I do not have a proper "runway" to take off from, I think I'm scraping that idea, but am very interested to try out how folding props work, so I'll go with that instead. Perhaps I'll have skids of sorts under the wing? No idea yet. Or, I could just have extra tall winglets that extend below the wing. I need to remind myself that the winglets need to be behind the CG for them to work properly.

Interesting interesting!

Monday, October 05, 2015

Kfm4 Flying Wing Post Mortem

Yesterday, I took the wing out for a flight in the evening, but it barely flew for 5 seconds before the motor cut, and I had to do a deadstick landing for real. When I arrived at the wing, the ESC was beeping the overcurrent tones, and the motor was just jittering back and forth very strongly when throttle was applied.

The motor was also nigh impossible to turn, even with the connections to the esc removed. A short while after, it started to free up, but it made clicky noises, and would sometimes just jam up for no reason. Seems like it threw a magnet :(

Having no spare motor, the only other choice was to take the CF2812 1534Kv motor from my Teksumo. Same motor mount, but it should have less torque and much higher rpm! I didn't change the prop and the wing flew fine, just much faster! I also could not fly as slow compared to the1200Kv motor, wonder why? Maybe the torque is not as good at the lower rpms but comes in at higher rpms? No idea....

Anyways, I took her out for a spin this evening, and she flew totally swell, as in the video below:
 Also compiled a selection of crashes :P

Unfortunately, this is the last time I will be flying her. It seems like the mods I made to hold the battery, as well as the holes used to hold down the servos have a very detrimental effect on the airframe, and the cumulative crashes cause the front section to fold up, as well as the left wing to fold up along the weaker portion by the servo mount.

She still flies, but tends to tip to one side, as I think the damaged section of wing, which actually bends upward, may be causing a dihedral effect. There are also other issues with the wing. While the front leading edge of the wing has 3 layers of DTF, the trailing wing section only has one section, and in reality is very weak. The 1 layer wing has detached around the motor mount, and I _think_ this changed the sound of the prop, perhaps because the air entering the prop now becomes even more turbulent?

I think if I were to remake this wing, I would make the following changes:
- More sweep to move the CG back. Balancing this wing has been difficult.
- A lighter motor - both for ease of balancing the cg. I also don't need the speed... for now.
- A carbon fiber spar, that would help the area weakened by the servo.
- Consider switching the elevons from foam to balsa (maaaaybe?) may improve handling if there is less flex.
- Perhaps 2 pieces of DTF minimum would help longevity.
- Figure out a way to allow thrust angles to be set easily! Ripping out the motor mount is a really bad idea.
- Colours or something to differentiate from top/bottom! There were several times I've lost orientation, not fun!

My next design will have the following requirements:
- Ease of building: Probably going with a plank wing and Kfm3 airfoil
- Prop safety: Prop will be high and not impact ground. (What about folding prop?)
- Minimum parasitic drag on wing
- Battery to be mounted below wing - perhaps the lower CG will give some amount of self-leveling, and not weaken the wing.
- Carry a mobius-type camera
- Carry a fpv camera
- Possibly have a tail section? vtail or elevator/rudder.

Good luck, me!

Saturday, October 03, 2015

Kfm4 Flying Wing Mods 2 Test Flight

Unfortunately, I had the camera angled too low, so out of 20 mins of footage, I had maybe... 20 seconds of aircraft, mainly in crashes XD

If not, the mods went very well, it was actually much easier to fly, I actually ran both batteries! That, is a win in my opinion. I first flew with the new thrust angle, which now had very benign behaviors in flight.

However, it still felt rather twitchy, so after I flew the first pack for about 10 mins, I added 14g of weight to the nose, and switched over to a new battery. She now flies with authority on the sticks! Much so that I tried some full throttle overflights as well as loops, and she handled it without any issues.

Loops perform very well with this wing, previously on my Nutball, it was nigh impossible to recover from a loop for some reason. This wing just pulls out of it easily. I also tried going vertical, then purposely stalled her while vertical. Once she nosed over, a little throttle brought her back into full control. I like this wing!!!

The main thing now is pitch sensitivity. She is *really* sensitive to the elevator input. I checked the transmitter when I got back, seems like the travel was set to 90%, while the aileron input only at 85%. Oops.

Roll on the other hand was great. Nothing like those crazy aerobatic planes you see, but perfect for newbies like me. 

Finally, battery life. My battery pack flew for about 10minutes. After the flight, the charger only put back 380mah back into the 1000mah battery (!!!!) This means, flight times of 15 minutes will be easily achieved, or, I can have the wing carry some heavier gear with no issues.

Really small motor!

Damn this thing is tiny! It's going to be used to convert my annular wing glider into an r/c aircraft. I hope I know what I'm doing!!!
Couldn't figure out how to press the prop into the motor, so I used a drill bit to enlarge the hole, then superglued the prop onto the motor.
The weight of the various components is 16g. The thrust of this motor/prop combo is supposed to be around 44g, so I have very little leeway if I want to get 1:1 thrust/weight ratio.

Here's a short video of it spooling up to 50% throttle, as well as how I wired it up.

Wednesday, September 30, 2015

Kfm4 Flying Wing Mods 1 Test Flight

The mods have made the wing much better. She still pitches up on throttle, but it's not as bad as the maiden flight. The elevon throws on the other hand seem to work very well, no issues there. Gonna figure out if I want to simply add down thrust, which appears to be the solution for wings I've seen, or to adjust the thrust line to give it a more pitch down moment of rotation.

Tuesday, September 29, 2015

Kfm4 Flying Wing Mods 1

Based on the results of yesterday's maiden flight, I've adjusted the motor mount to give more or less a zero thrust angle, and also setup the servo horns so that they give much, much more throw.

Evidently, I did it the wrong way round, resulting in the *least* amount of throw possible! The new setup gives as much throw as possible without binding. There is a fair bit of difficulty in getting the pushrods to be exactly correct, and after snapping many pieces of 1.3mm piano wire from attempts at bending/straighten/bend - I gave up, and used a cut down piece of bbq skewer to join the two control rods using CA, and then shrink wrapped on top of it. It appears very strong, and I hope it does not give in a crash.

The battery is also now mounted flush into the body, with a thin piece of ply to support it, and hold the velcro strap in place. The unfortunate result of this modification, is that the wing now flexes a fair bit more.

I also placed the battery further back, partly for structural reasons, and partly because I want to have space for the FPV gear. In order to balance it, I needed to put in 21g of weight up front.
Which brings me to this! This package arrived from banggood today. I just checked, this purchase was made on the 13th of August, so this took over 6 weeks to get here! Not a good idea if you are in a rush :)

The contents are very well protected by this rubber-like material. I did a quick test, and it works with the fpv screen I bought previously, so yay! I doubt I will fly it any time soon, as I want to get confident flying the wings before I do any fpv flights.

Monday, September 28, 2015

Kfm4 Flying Wing Maiden Flight

I think the basic planform is fine, it's just the finer details that need to be tweaked. The thrust angle is probably the main thing, I'm going to remove it totally before I fly it again. The elevons also have very little command of the airframe, and I'm not sure if it's because the wing is flying slowly and thus the control surfaces do not provide much force, or its because I need much more throw.

The other thing I'm going to modify before the next flight is the battery - I'd velcro'd it onto the wing, but it came off in one off the flights. I'm going to embed the battery into the airframe like my Teksumo to be held down with a velcro loop, that will keep things tidier, and probably less drag too!

Sunday, September 27, 2015

Kfm4 Flying Wing Build Log 08

She's all done and ready for her maiden! Still have to figure out a name for her :)
For the ESC, I was waiting for a delivery from overseas, but as I had a full weekend free, decided get this aircraft complete this weekend and bought an ESC from the lhs instead of waiting.

Originally I wanted to get a 20A ESC, but I did a quick static thrust test this morning using the heavier-duty electronics on my Teksumo, and I was getting an average of ~10A with the Emax CF2822 1200Kv motor. Armed with this knowledge, I had two options at the LHS, a Hitec 20A ESC or the Castle Creations Talon 15.

I've been quite curious about Castle Creations products, and the ESC weighed only 7-ish grams, and has a 50% buffer for the current draw, so decided to go ahead with it.

Testing the static thrust on the CF2822 with the following props give me the following results:
  • 7x3.8SFW / 9.91A / 570g ~ 59g/A
  • 7x5E / 9.05A / 480g ~ 53g/A
  • 8x3.8SF / 12.3A / 690g ~ 56g/A
  • 8x4E / 10.6A / 590g ~ 55g/A
Looks like I'll be going with the 7x3.8SFW for the maiden. The 7x5E prop is possibly stalled, and work better only in the air. But we'll see :)

Friday, September 25, 2015

Kfm4 Flying Wing Build Log 07

Almost there! Got the control horns into the elevons, and glued on the winglets as well.  The wing now weighs in at a beefy 317g, and this weight will only rise once I add in the pushrods and electronics.

The only big thing now is to fashion a motor mount :)

Thursday, September 24, 2015

Kfm4 Flying Wing Build Log 06

Spent last night and tonight taping up the wing with packing tape, and the leading edge with some super heavy duty gorilla duct tape. Without the tape, the wing weighs 56 grams. After adding on the elevons and adding in on the packing tape, it now weighs 103 grams!!!!

In addition, I've tried gliding the wing, and it is very slightly tail heavy. Adding in a 3 gram weight (2 x 10 cent coins) and the plane glides forward slight nose heavy. Checking the CG, it is at the 35% of the way along the chord. That's way behind what's the supposed CG, but I'll run with it and see what happens :)

It seems like the elevons are considered part of the wing area, and they were not included in the CG calculations. Adding them in, it seems the CG of the wing is actually at 25%, so yay!
Added in the servo as well!

Wednesday, September 23, 2015

Kfm4 Flying Wing Build Log 05

According to the CG Calculator for my wing, for a 20% CG position, it's 11.8mm from the leading edge of the wing. Unfortunately, this requires a fairly heavy weight up front in order to balance the motor and prop! I knew there had to be a reason why the popular wings tended to be more swept back! The more swept back the wing, the easier it is to get the CG right as it is moved further away from the leading edge.

Several solutions, apart from adding weight, present themselves. A light motor would help alot, and I'll probably even drop the prop down to a 7in, no idea if it'll save weight at all. I tried putting my 3s 2200mah battery up front, that balances it up well enough, but is over double the weight of my 1000mah battery, so, not particularly ideal either.

I've also tried putting a 40A esc up front by the battery, and that helps too, but it's overkill as the motor is theoretically rated for up to 14A. In the end, I'm sure it will be a combination of all the above to get the wing just right.

Testing the CG at the 25% position _somewhat_ works. I'll cross that bridge once my esc arrives.

Ah, the things we learn :)

I've also quickly fashioned a pair of winglets. It seems like in some flying wings, it's possible to get yaw stability by adding in drag on the leading edge by chopping the corner off the leading edge. While this is a cool idea, I decided to go with the winglets instead as adding in random things I hardly know about is not a very good idea. Heck, I have no idea how to design this wing, just going by seat of the pants intuition here.

Other things I've prepped include the control horns for the elevons. After I've had control horns fly off in flight on my previous aircraft, I've decided to play it safe and use a proper dubro control horn. To spread the weight of the control horn onto the elevon better, I've cut small plywood sheets and foam-tac'd them on.

I'll need to figure out the servos as well!

Tuesday, September 22, 2015

Kfm4 Flying Wing Build Log 04

Added in the elevons :3 I must say I quite uncertain how to attach them - should I use some kind of hinge (I bought du-bro hinges)? In the end I decided to KISS and attach them using hinge tape - aka 3m blenderm.

I've also sanded down the leading edges to more of a "regular airfoil" kind of shape... only to realize, how was I to do it on the other side? I should have just left it. Oh well, we'll see what happens :)

Next up I could probably tape down the elevons with some new 3m tape I've got - 3m Storage Packing Tape. It's supposed to have a stronger Acrylic adhesive, and unlike the generic packing tape I got from the post office, it's thinner and amazing goop actually sticks to it very, very well - as well as foam tac.

The next step is to fit the servosin!

Monday, September 21, 2015

Kfm4 Flying Wing Build Log 03

The main wing itself had the leading edge sanded down. It seems like the Readiboard is very easy to sand, though the Gorilla glue wedged between the layers does make it more challenging. I'm not entirely sure of the blunt leading edge of the airfoil. Most people who do the bent kfm4 airfoil definitely have a much more aerodynamic leading edge. I'll see what I can read up on this online and decided if I want to go further.
The motor chosen for this wing is the Emax CF2822, 1200Kv motor, and I've got a medley of props to try out, but decided to go with the APC 8x3.8SF for a start as I am not looking for speed. That said, I hope the prop is fast enough to take us beyond stall speed......
For the motor area, I've added on another piece of foam to reinforce it. Hopefully this will work!

Right now, it's weighing in at 56g, without the elevons. Everything I've got piled on takes it to about 300g. This will probably go up again once I've added in some packing tape to firm things up! The main component I'm missing is really the ESC, hopefully it arrives this week!

Sunday, September 20, 2015

Kfm4 Flying Wing Build Log 02

 I've got the main parts of the wing glued together with Gorilla Glue.
Next I have to shape the leading edge. The wing flexs quite strongly though, I'm hoping once I apply a layer of packing tape, it would help.

Saturday, September 19, 2015

Kfm4 Flying Wing Build Log 01

Something that I'm working on, a blunt-nose flying wing that will utilize the Kfm4 airfoil. I originally got a rough idea from a flying wing that I know works - the Teksumo - then I plugged values into this Flying Wing CG Calculator to give it the width of a DTF board, lesser sweep, and a blunt nose.

After that, I brought the design into Houdini, and adjusted the rear end of the wing to have the motor fitted more forward into the wing in the hopes this will help balance the CG easier. Also, I widened the rear in order to accommodate up to 8 inch props.

Friday, September 18, 2015

PID Controller experiment

Something I've been very curious about, so decided to extend the pitch/roll estimation code I'd wrote to drive a stablized servo. Seems to work pretty alright. When I twist the platform rapidly, it does overshoot a little before it stabilizes, and I think, apart from the PID code itself, could also be something to do with the settings of the accelerometer/gyro.

Thursday, September 17, 2015

Annular Wing Glider

Got a quick video of the annular wing in flight :) I've ordered some micro components in the hopes that I can make it fly :)

Wednesday, September 16, 2015

It flies!

Or rather, it glides! After observing that the wing would spin along its longer axis, I thought about putting in a "fuselage" up front to balance the upward moment.

Before I put the fuselage on though, I noticed the wing, depending on which side I threw it, would pitch upwards, while the other side would pitch downwards.

I thought that if the wing pitches up, the fuselage up front would serve to balance against this upward pitching.

And I was right! I taped a strip of foam board up front, and upon throwing the wing, it flew upwards, before falling on its butt. This meant* that the weight was too heavy behind, so I taped on a small piece of plywood to the bottom (see the two tiny pieces of tape sticking out from the fuselage).

After adjusting the plywood weight forward and back, I managed to get it so that it would fly straight before it lost lift and crashed! Wooo!

With this, I am very confident I will be able to get it flying with a motor. I'm probably going to make it a very simple airplane controlled only with a rudder and throttle.

Some notes:
- "Aspect ratio" of the wing before it is rolled up is 5.6; 50.8cm x 9cm.
- The center of gravity is roughly 10mm from the leading edge of the wing.

*this is based on what I've read about aeronautics online; do not take this for science or fact as I do not have proper training.

Tuesday, September 15, 2015

Annular wing

I read about annular wings today, and on a whim, decided to just make one from the leftover from from the previous build. Apart from plain old curiosity, I'm using this to test some 30 minute gorilla glue.
Interestingly, when I tossed this into the air, it goes forward for a few feet, before tumbling into a spin along its longer axis (wanted to make a circle, but didn't realize how much strength the packing tape would make the joint flat.).

I'll probably get around to building a rudder of sorts and a "fuselage" that leads the wing. See if I can make it glide. Should be fun :)

Sunday, September 13, 2015

Nutball RET Build 05

Finally completed the Nutball build! I'm calling her Cat Scratch :)

Right now, she's balanced at maybe 26-28% behind the leading edge of the airfoil. Seems to be fine?

One of the things I decided about the build was to use only hot glue for all the parts. Hot glue unfortunately, appears to weigh a ton! While I estimated Cat Scratch to come in just below 200 grams, she now weights in at 217 grams!

Upcycled some plastic from a plastic box to make the control horns. They were rather flimsy, so I put in a short stick of basswood to accompany it.
She flew really well, and I hope to get a video tomorrow :)