Gliders – Life..

Oi, it’s too heavy!

DG800 Comments Off

Apr 112020

Yeah, sort of expected that to happen 😉

With the added mudguard and wheel bearings and other small bits, the Hitec 645MG is struggling to get the gear up. There is a point halfway between up and down, where max force is needed, it’s just how the design of the gear works. In theory I could redesign everything. (Yup, maybe sometime soon). Or I could add another voltage regulator to give it it’s own supply, 6V would work (most of the glider runs on old 5V gear), or solve it for now with slightly more powerful servo.

I found a SAVÖX 1256, which has probably twice the torque of the Hitec, so will strap that in for now.

Of course with the way I wired things up, that’s easier said then done. Since I installed a 9 channel Rx in the plane, and needed an extra channel for the Flashy Lights, I came up with the cunning plan to use a single channel for multiple things.

In short, gear up or down is only 2 positions. Light on/off same thing. So why not do a bit of mixing and send the resulting servo signal to an Arduino-Pro-Mini, and let it drive the LG servo and Lights. I cooked that software a year ago, knowing it was a quick fix for a self imposed problem. (That’s what this hobby is all about, if you don’t have a problem, make one!)

Anyway, long story short, the pulse that the servo needs for up or down is hard coded in the software. No biggy, but it means it’s not very convenient when you change servo’s.

Oh, it’s sooo much fun. With the aid of my little magic ToolkitRC.com M6 I measured the output pulses to the servo. 1000-2000mSec. Perfect, but the servo only rotates 90 degrees and a bit? (By the way, there is an software update for the M6, V1.31 dated 23 March 2020)

Oh dear. Now what. Time for a rethink, and do remember in future that you really want a 180 degree servo!

After some reflection and relaxing in the sun, I remembered that I used to convert servo’s to 180 degrees by adding a few resistors to the feedback pot. That triggered of course the thought ”did I maybe modify that servo?”.

*2 * 1.5k resistors make it a 180 degree servo.* (you call that soldering?? Sigh.. One gets older and the hands less steady…)

And the answer is yes, I did! Funny enough I posted that same fact on 3rd Dec 2016 on my Facebook account. Oh where would I be without my facebook memory. Scary..

Well that sure was a fun exercise for a locked-down Saturday. So next question is: Am I going to modify the Savox? The answer is below. Same trick, 2 * 1.5kOhm resisters either side of the potentiometer will do the trick. Funny this servo is rated to produce 4096 steps. It never stops to amaze me how you can get that resolution from a cheap 5k pot. But they work, so I’m not counting! by the way, there are no wires in this servo, which should make it more reliable (cheaper). But it does mean some sort of skill is required to remove the pcb!

*Luckily there’s enough space for 2 resistors, same 1.5kOhm as on the Hitec. Rotation is now just a tad under 180 degrees. That will do nicely!*

And while at it, might as well try to sort out the wiring mess a bit. I’ve got some space at the top of the fuselage, out of sight.

By the way, that stepdown converter acts as a current limiter as well. Max current the chip will produce is 4 Amps, stall current for the servo is 5 A. Should be safe. And since it is only ever used for up and down, it is not likely to get warm. And if it does, it will disconnect, saving the battery. In theory this is what is supposed to happen. Real life might work differently.

So, that’s enough for Corona-Easter-2020. Left’s hope and pray the world will not have to repeat this ever again!

What a difference a month makes.

Corona, DG800 Comments Off

Apr 072020

To say we have never experienced anything like this lock-down is an understatement. We are lucky to live in a nice place, with lots of space, so we should be ok. Even if this madness takes a lot longer then the official guestimates that our gov’ment now spreads, I will keep myself entertained.

Saying that, I managed to mess up my back (again) which sorta restricts my movements at the moment. Hence the lack of stories.

I have finished drawing the metal parts for the SA-750, and are waiting for the nice laser people to cut them for me. Obviously my parts are low on their list of things to do, they likely have other more immediate pressures on their business. Never mind, lots to do.

Last year I hardly flew the DG800, mostly because our field was dry, so unbelievable dry, that the stake I use for the bungee did not hold. I once had that metal spike flying in my general direction, and that was once too many times. I’ll try to think of a better solution for tying down the end of the rubber. I probably need at least a double stake, and most likely longer and heavier. And that’s the pita I want to avoid, I don’t want to drag all that stuff to the field. I’ll have a think about it.

At the moment the field looks fine, I could use the single stake, but you guessed it (or not if you read this in years to come) we are closed for business due to the Corona virus. Sad as it is, we are a sport, and all outdoor and indoor sports have been banned. It does not seem logical to us, but the gov’mnt does not have the time to look at each sport in detail to see if it makes sense. So, everybody stay at home, no exceptions.

So, do some maintenance. I knew I had a flat tire. Sorted that by inserting a length of silicone tubing inside the wheel. (I know, I could have bought a new one. No Fun). Then, since I have them, added some bearings to the wheel, that never hurts. I also wanted to make a mudguard, just to see if I can.

*wheel with bearings, the original plastic one did not survive my ‘homecomings’*

The plan is to print the form (positive) slap on some fiberglass and see if it looks like something I want to use. Right now the vacuum pump is doing it’s best to maintain -0.6Bar. I lost the manual for the little thingy that decides when to turn on and off, but it seems to work, so will look for that later.

I would be better off giving the walls a slight angle, so that it is easier to pop of the form. With this version I had to split it to get it to loosen. But in the end, no harm was done, and it looks good enough for now. If it survives, and this lockdown continues, and if I am getting bored, I’ll do another one. This one is approx. 8 layers of 25 gram and one of 225 gram. I have miles of the thin stuff, I use it to get a nice surface. (It was nice until I had to split it in half to release form the form 😉

How the Blaster-1 became a E-Blaster

3D print, DLG Comments Off

Mar 032020

As I mentioned the other day, I decided to turn the Blaster into something Electric. Mostly because I don’t know what else to do with it..

All up weight is now 435 Grams, so that is 81 grams more then without the E. Don’t know how I got the 19 grams earlier. Still happy with it.

The spinner seems to have a slight imbalance, but with a 2S lipo and low rpm it stays together for now. Something to look into later. First we needs some test flights. I also need to think about keeping the prop tight to the fuse. The usual rubber band trick will probably be employed once it flies.

So what’s the plan for launches? Not sure yet, toss it like a normal DLG and hit the motor switch once you release? Need to remember this one has a history, so full power launches will be a bit scary. Anyway, we’ll see.

It actually looks quite nice. Sadly the stab and rudder have some damage caused by a once in a lifetime mini tornado that lifted it and tossed into the fence.

Always great to figure out later how it should be done. For the next version I should keep this in mind. Or the power setup for a snipe.

A bit of nostalgia.

DLG Comments Off

Feb 252020

This image has an empty alt attribute; its file name is IMAG0006.jpg — Outside Rostrevor, Yellow Road, looking towards Hilltown. This was sometime 2009 I think.

Of course I did the smoke test today. Mounted the motor, connected a 3S battery and hit the throttle.

I ran the Emax 2204 motor for 10 secs before I could fry an egg on it. Hmmm, maybe I should have looked beyond ”it fits”?

An 8*4 prop is not quite the same as a 5*4 drone bit of plastic. No problem, what else do we have in the BigBox of Stuff? Ah, look at that, sort of ancient history here. A HET-RC Typhoon Micro 6/3D. More or less the first motor I got just before the foamy craze started.

Specs:
Weight : 35 grams
KV : 1460
Max Current : 12 A
Power Nominal : 90 Watts
Recommended Props: APC E 9 X 4.7

The 9*4.7 is what is relevant here. Ok, lets see what E-Calc says:

50 Watt on a 2S Lipo with almost 4.8 m/s vertical performance at 370 gr RTF, and a 5 mins motor run on a 450 mAh battery. Ok, no problem. Lets go!

Getting a bit nostalgic there while looking for the plane with that Typhoon. At the top is my Blaster in good ol’ N-Ireland. It had a variety of radio gear in it, this is I think the Spektrum-Mpx version.

This image has an empty alt attribute; its file name is dsc032291-1024x768.jpg — ..and before Blaster was this one, think it had foam wings with doped on glass.

Can’t resist looking back: Yellow Road. With the right northerly you could hang for an hour in the breeze, untill your fingers turned blue. Further back was a similar bowl facing south-ish. That was the better spot. My first flight with the Birdy lasted 30 mins or so.

And I found it! First ever CNC-ed plane. Not a real serious design, just made it, because I could. This was powered by that HET-RC Typhoon. Did fly well enough in the backyard!

..meadow at the back of the house in Rostrevor.

Just checked, after 10 years my car is still parked there!

Blaster conversion

DLG Comments Off

Feb 232020

While waiting for some parts, I decided to have a go at another project that’s been waiting to be started. I still have my original Blaster 1, RTF is approx 350 gram, and while it was fun flying it from a slope, it always a struggle to throw it higher then 35 meters on a good day. In the meantime I have something black that weighs 220 gram, and does go a lot higher!

when I was young

That says much about my technique! Anyways, I’m electrifying it. There’s some quad engines lying around, some small Lipo cells that appear to be good enough for a few more flights. All that’s left to do is some radical surgery.

The first cut is the hardest, after that it’s a matter of making enough room for some servo’s and Rx, and somehow getting the CG sort at the right location. As always, I’m using the TLAR technique to get the dimensions right. There’s still a bunch of D47’s from Indoor days gone by, I’m sure I can find a receiver that will do the job, so I’m almost finished, just a matter of assembling a few parts.

I could not find the right size aluminum in my stash, which is a good excuse for doing a quick printed version of a prophub. I have a few 8*4 foldable prop blades, not really fit for this purpose, but I’m not using them for anything else. The first straight center part looks good enough, but then I wanted to have the blades tighter to the fuse. Some headscratchings later I have a fully printed foldable propeller including spinner part. Printing is is just rough and quick proof of concept, not the final one yet.

In the meantime I started preparing the fuse. Those were the days that Vladimir used kevlar for the front end. Real fun when sanding!

Will a printed part be strong enough to hold on to those blades? The answer to the question will have to wait till I assemble the battery. If not, I can always fall back on a proper 5 euro part.

*looks right on the money! Need a few more grams shifted forwards. All up weight is 20 grams more then at the start!*

That looks about right! so far 19 grams more then when I started, I need to add some glass around the front end a something to hold the servo’s. Also a small lid to stop stuff escaping. CG used to be at 78.7 mm, 3 mm to go!

I’m very happy with this!

Another bit of Black Magic

DLG Comments Off

Jan 042017

During our holidays in the home country I was entrusted with a handful of carbon, with the request to ‘just build it and enjoy’. Over the last few weeks that building process was finished. Even though the total amount of hours spend are not that many, it all adds up. Today I finally got a new receiver, so after the new batteries arrive, we should be all set to go. All up weight is 220 grams, which probably is a bit on the light side, if I compare it with the Tweagle. I ended up adding some extra weight to that one too. At 245 gram it has better penetration, and it fits my style better. For this one I decided to make the wing detachable with a home made connector. The pins originated from a scrap cable assembly. (Good thing about working with medical equipment is, that there’s lots of good stuff that we throw away.) Of course I have read stories about bad connections. This one will not have bad connections!

More after the first flights!

DG800-4

DG800, Gliders Comments Off

Jan 042017

It has been some time, but today is as good a day as any other day for a wee update. A lot of time has gone into designing and building a retractable u/c. The final result is good, even though I say so myself. I still want to make a mudguard but that can wait.

Making the wheel doors work properly was alo a lot of work, where I had to made a negative from the fuse, and build the doors into that. (The old vacuum installation was a great help here! )

DG800-3

DG800, Gliders Comments Off

Aug 252016

Mounted the elevator servo, I found a one in the box that will do nicely. I wanted to use a beefier link to the elevator, but there was not enough space. So a 2 mm version will have to do for now. Maybe change it for 3 mm if I work out how to do it.

I also cut slots into the rudder for hinges, but in hindsight I want to redo them in such a way that there is less visible ‘hinge’ on the outside. The whole rudder needs to be removable, there is a plastic rod for a 1.5mm steel wire built into the rudder, so this is easy.

Next task will be to think of a way to make a quick disconnect link to the elevator. I don’t want to use a standard quick-link, they do fail with repeated opening/closing. It has to be simpler, and less fiddly in daytoday use.

Let the mind think about it for a bit, it will find a good solution!

Flying this week is a bit of torture to be honest. 30 C plus and clear blue skies, with a slight haze is not the best weather, simply because it is very hard to see the plane beyond 200 meters altitude. No doubt I will regret saying this soon.

DG-800-2

DG800, Gliders Comments Off

Aug 202016

Part 1 is a bit back, describing how I did a quick and dirty cockpit frame. Today was the start of more serious stuff, like drilling the holes in the fuse for the all important bit in the middle! First I created a jig that holds and aligns the fuse, and made very, very sure that everything is perfectly level and square. Lasers and camera’s don’t seem to like each other, hence the lack of quality in the pic. I will probably be able to do another one, once the first expoy has hardened. To tricky to touch anything at the moment.

Once the sleeve is in position, I can cut off the outer parts, which will go into the wings. The manufacturer states in the manual they kept the hole in the wing slightly oversized to allow for wiggle room. What slightly worries me, is there anything other than the sleeve in the wing holding things up? Do I need to add something? Glass the wingroot maybe? Time for more research!

Logging your flights

Gliders, Insider Comments Off

Aug 202016

I discovered a fun website the other day, where you can ‘virtually’ compare your achievements with other pilots. Of course I am no match for 6 meter ships, but it is fun. Soaringleague.net is the place to visit. It is a pretty new site, I guess it’s real goal is to log GPS flights, but it works fine for me too!

Tagging the flights is a bit of an adventure yet, but I am sure things will improve over time, since the admin, Pascal is working really hard on it!

My best flight sofar was a mindbogling, neck hurting flight of altogether 33 minutes. I defenitely need to invest in an easy chair to sit through long flights, standing and looking at the sky does not work!

Up to this point in life I had been concentrating on 10 min fligths, which are not to hard, but stretching things beyond 10 min is hard work when you start from 200 meter or less. (my trusted lady always tell me when I cross 150 meter, so usually I switch off at that altitude and a bit. )

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