Category: crash


Hello,

I am proud to announce that I had my first proper crash. It comes sooner or later, you cannot avoid it. Mine came today.

We went out flying with HaBoRC, even though that the city was covered by fog. We thought that it might clear up during the day so we took our chance. When we arrived to the field conditions were far from perfect. I could hardly see the forest close to the field. I took a sweep recording, that shows a more cleared up view actually, in the beginning it was much worse.

Our initial activity involved recovering a plane that was crashed onto a tree some 7 meters high from ground level. We constructed a set of poles (taped together with Duck Tape, a special version of the famous Duct Tape actually 🙂 ). One member of our team was brave enough to climb up on the container containing gardening tools and nudged the plane down carefully. It was as slippery as ice, the fog made everything wet.

HaBoRC started to fly with his flying wing, I took off shortly after him. We agreed to fly close to the field so that we don’t lose sight of the planes. So did we. I started to turn tight so that the plane would stay in sight. I managed to make contact (collide) with the flying wing. I lost orientation of the plane (was extremely high adrenaline all of a sudden), to stabilize it I leveled it out. I was close to the lake, wanted to avoid it. Leveling out was good, but this enabled the plane to fly out of my sight, it went into the fog. I was desperate, tried to turn back blind but realised that with power on in the fog I will just smash it, so I chopped throttle and hoped for the plane gliding smoothly onto the fields.

What I managed I was unsure of. The very last moment I could turn away from the lake, that was good. But did it manage? Or is it in thousand pieces?

I started to walk into the generic location where it went lost. Unfortunately HaBoRC had similar problems. He looked at me fighting and forgot about his own plane. It went into the fog as well. We lost 2 planes within the first minute. Not good…

I walked along the small road and then discovered the plane. It was stuck into the soft vegetation covering the rocks. Pointing downwards, but the wings were on, control surfaces were on. Even the shape was normal. As I got closer I could see that it was gliding against a huge pine tree and ricochet to the soft bush. I could move the ailerons, elevator and rudder. Even the prop could spin up. The only thing missing was the canopy. I tried to find it but the fog was so thick that I couldn’t. I thought that it might popped off when I collided with the flying wing.

So I started to wonder around in the deep wet vegetation behind the field. My boots got totally wet, socks wet, then the trousers got wet even. Nothing. I thought that I might find it when the sun comes around. Recorded the others flying then I got back to the pine tree when the fog cleared up. And there it was my canopy. Close to the other big pine tree. That might took the first contact, the canopy popped off and then the plane crashed into the bushes.

The plane glided so far in the fog.

When I got back HaBoRC recovered his flying wing as well. I just tried to help him, wondered around the motorcross track and when I was back he had his plane as well. Great relief, I felt really badly after colliding in the air.

After a while I started flying again and could record some nice low passes. I still haven’t got my 2nd mini camera working, the replacement battery haven’t arrived yet.

Could record some nice multicopter flight. Quad- and tricopter. And some airplanes. I fetched some chocolate coated cookies, they were a welcome addition. Club members could replenish energy when needed. I will need to get some portable gas burner and make real coffee. Could a future project 🙂

Please see the recording of my flight here.

Hopefully soon I will get my Hobbyking Wing Camera and can get you much better looking recording.

Best regards,

Sir Crash a Lot

Hello!

The curse is lifted from me, finally some nice weather again 🙂

We summoned with some club members at Balltorp field and got our dose of flying. Great times!

My little side project was about to get more interesting recordings from the sky. I had 2 new mounting points on the plane, on the fuselage, under the main wings. The idea was to mount the mini camera pointing downwards and recording “satellite” images. I thought that if I can get very high up and get a good wide-angle view it will look nice.

Well, it did not go so well as I hoped for. One of my cameras died prior to flying. I charged them up from the USB port and went to flying. Unfortunately these 15 dollar cameras don’t really come with any user interface. There is 2 amber coloured lights on it. By shining or blinking them the camera tells you what mode it is in. Or by not responding to the buttons it tells you that it either crashed or just drained its battery. Or in my case just died off.

As far as I understand the charging and battery management in these cameras are not so sofisticated (you can guess from the price), this results in battery overload. I dismantled my camera to examine it. The battery is a 1-cell Li-Po with some 160 mAh capacity approximately. In ideal case it provides juice for 45 minutes. However when you charge them on USB-port you do charging with 500 mA current. That might be too much. Or the battery management circuitry does not protect it from overcharging well enough. Anyhow my camera reached its end of life. At least the battery did.

Luckily solution is not far away. I went on the Internet and found this! (quote from Top Gear 🙂

It is a 240 mAh 1-cell LiPo with a standard JST connector. I just ordered such connectors, so I could solder a connector onto the camera, lead it outside of the plastic housing and attach this “proper” battery on top of the camera. So I could charge it from the iCharger charger with proper current and without overloading it. I could check its drain level with my LiPo Cell Checker and I could have the camera for longer time. Why dispose something when you can mend it?

We shall see how well I manage with this. First I will check if the camera is able to take pictures from the USB port. If it does not work then it is maybe not much idea to attach the external battery since the camera itself is broken even. I need to investigate further.

Back to the flight. The weather was reasonably good.  Some clouds, some wind. Later the wind picked up speed but it was manageable. I did some good hand starts (I am still learning to throw with left hand). Then I had some really bad start attempt. There are some insects that love to fly around the eyes. One got into my eye precisely when I launched the model. I have got totally distracted and launched the plane into the ground. Very embarrassing. I became nervous and did it again, now without the insects, just me being clumsy. This did not really help. So a club member launched the model for me, then I calmed down and could continue flying. Pretty ashamed I was, dropping the model twice is just silly.

I did some high altitude recordings and then I noticed that the other camera (the one still working) was drained as well. I assume that the internal battery is giving in there also. So I might need to upgrade it.

I noticed that even though that I bought these cameras from Hobbycity I have two different batches. One renders pretty nice green colours and handles light changes quite well. The other (the one still working) is worse. It renders more like cyan and blue colours and is pretty bad in high contrast situations. Like sky/ground scenario. Which is little unfortunate when you try to use it as an airborne recording device.

So I am very much looking at this.

It is a much better camera from Hobbycity. It has 720p HD resolution. Not FullHD, but 1280×720 at 30 fps is far better than the one I have right now (being 640×480 with crappy plastic lens and much noise).

A pretty good comparison of what you get is possible to see on following Youtube video.

Author is ultralajt, he made a video comparison of both cameras on same plane. Basically you get much better dynamic range, much longer battery life and much nicer wide-angle view. For roughly twice the money, this one costs 35 USD without memory card of course.

It is far from being a GoPro HD Hero action camera, but the price is far from it as well. I think GoPro would be a later step, when you are flying like an ace then you would put such a marvel onto the plane. Not me. Just look at me launching my plane into the ground twice this weekend 🙂

I flew out all my 6 batteries but the day was far from being over. I recorded some Tricopter action. HaBoRC built one and flew it first by eyesight, then by FPV. We helped him by telling altitude, so in initial takeoff phase he did not get disorientated. Quite fun it was. The footage looks great.

Another colleague came with a Quadcopter. That is a funny beast as well. There was a Yak55 even. HaBoRC showed some acrobatics with this light plane in turbulent conditions. The cherry on top of the cream was when he catched it while hovering. Another club member recorded footage of this.

All in all it was a great day. Here is my recording.

Best regards,

Sir Crash a Lot

Hello,
My 7th flight has happened. As one of my favourite bands say: “7th son of a 7th son”. Look it up, great song.
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This time the flight took place at our club field. Weather was not really promising, we were anxious about rain. Not without reason as it turned out. The whole week was more or less rainy and weather prognose did not really calm us. However it looked like that between 18:00 and 20:00 it should not rain. And finally after long weeks of misfortune the prognose was aligned with reality. I think the guys at Weather Institution were doing their best 🙂
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I made a sketch of my flight profile for better illustration. I call it a Hi-Lo/Hi-Lo profile, I lended this expression from military terms. There you can have different techniques for ingressing and exgressing from the hot zone, depending on the altitude profile these are called similarly. Anyhow this is a peacful mission, so no weapons are on board of my humble Easystar.
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What I do you can see on the graph. Horizontal axis is time, vertical is height. I take off, do maybe a quick round and then climb against the wind as steep as possible. This phase is on full power, the plane climbs at maybe 60 degrees against the wind. I gain height and climb as far as I can see the plane against the sky or clouds. This is approximately 250-300 meters. I estimate it based on the sound delay when I chop throttle at the end of the climb. Sound travels at 340 m/s roughly, so 1 second delay would be approximately 340 meter distance. As I can only estimate the angle I am above horizon (the azimuth) height would also be a guess only. But something like 250-300 meters. Quite high actually, you can see very far away on a clear day from that height.
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When I am up there I close the throttle and start gliding. I do some circles as well to record as much of the sight as possible. Then I glide along the field with the wind, do a turn and glide against the wind. And repeat this as long as I have altitude left. To lose altitude quicker I can do some loops or half rolls. Quite fun. Since I have stiffened up the wings doing a loop will not bend them so much as without stiffening.
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When I am close to the ground I do a school turn (an oval above the field) and then turn into the wind and climb again on full throttle. This enables me another climb to altitude. Then I glide down and land. These 2 climbs and glide sessions fit into the 7 minute window that is advised, I drain the battery to something like 3.8-3.9V per cell. This is a comfortable storage voltage. Then I can change battery and take off for a new round.
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I managed to fly 5 batteries then it started to rain. The last flight was almost in the rain, I bled altitude with multiple loops to not get the plane soaked. Could record some other flights meanwhile, a Sukhoi-29 and a QuadCopter among others. The Sukhoi was a big aeroplane, built from balsa with film cover and a massive 6-cell setup. The battery is like a half brick, the electric motor is of size of a tomato. Impressive. Even more impressive is the noise of air whistling around the plane as it travels. Very nice exprerience.
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I had one small incident, managed to do a faulty start in the beginning. I did not have the hand on the yoke, just launched the plane and then it fell on the grass. Stupid mistake. It did not crack, but anyhow rather embarrassing. The next start I had the hand on the yoke, so I could recover from the dive and do a proper takeoff.
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Thank you,
Best regards,
Sir Crash a Lot

Hello!

Summer should be normally the time when I can fly my plane. Weather is nice, I should have free time. But practice is showing other picture. In summer I have to comply to company holidays. Due to industry standard 4 week long holiday there is a “shutdown” period during which I practically have to take out my holiday. Due to family reasons some of this time is reserved by family visits. So the available flying time is much less than the original holiday.

Add some weather contraints and you can see that time rushes away and I hardly fly. Anyhow, waiting is over, I made my 5th flight yesterday.

I wanted to try a new location, that is much closer to my home. Until I haven’t got a car I need to consider public transport, this location is only 50 minutes away. It is called Arendal, the industrial/port area of Gothenburg. There is a grass field there, where I could meet with my colleague. I think it is no longer a big secret, he was visible on many videos already, HaBoRC is my flight company. I learn a lot from him, get good advice and practical help when I am stuck with some problem.

Last time he recommended to learn hand starting. It can happen that the grass is taller or you just want to spare some battery power and would like to start the plane from your hand instead of from the ground.

First you have to think it over. To do a good hand start you have to do following:

– do all pre-flight checks. Safety first!

– turn into the wind

– have the transmitter in your hand, hand on the yoke

– get a good grip on the plane, so that you are safe from the propeller. Even when throwing the plane, keep in mind the whole sequence!

– pull good amount of throttle on the stick (max power could be needed)

– align the plane with the ground, throw it forward. If you have great power reserve you can throw it slightly upwards even (maybe 10 degrees, try your ideal values)

– immediately after throwing compensate on the stick (you have your hand on it during throwing)

– recover from the slight dip while the model gains speed

– decrease throttle to a gentle level and start you ascent

If you do everything right you will not get any injury on yourself, nor on the model. Keep in mind safety, the propeller is no toy!

My first start was almost a crash but I could recover. Since I am right-handed launching the plane with left hand felt very awkward. I was never good at throwing stuff, so it felt like a giant leap forward to learn hand starting.

I experienced with flying at bigger distances now. Made “huge” circles around, tried to orient myself when the plane is tiny little in the distance. Later I experienced to fly into the wind at 2/3 throttle and flying up into great height even. Then I pulled down throttle to zero and did glide around. Easystar is a great glider for a motor plane.

Since I had 6 batteries now I could fly double the time. Great way to learn more.

At the 5th battery I felt myself talented and brave and did 2 loops. It went well, I compensated with the throttle during ascent and descent, so they were almost circular loops, no ovals.

At the 6th battery the “devil horns” started to grow unfortunately. I felt brave enough to do a loop directly after takeoff. Into the wind. That resulted in some adrenaline rush. The wind picked the plane up and threw it backwards, so it went over my head. Over the head orientation is very difficult. So I made only a half loop and tried to roll it back to normal flight while wind pushed the plane away and towards the ground. I could recover, but just. Easystar is not really keen on inverted flight, it wants to fly normal. Doing such a stunt so close to myself and so low altitude was just plainly idiotic. I almost crashed, a good lection. When you start to lose respect it is better to land and think it over.

Anyhow I flew around and wanted to improve my low speed gliding skills. Unfortunately the “devil horns” were still there. So I was gliding close to the bushes/trees and lost speed over them. The inevitable happened, I stalled it onto the treetop. As Captain Slow would say in Top Gear, “permission to say cock”… 🙂

I am no good climber, but tried. The bushes were not strong enough to take my weight, but were strong enough to hold the plane. I never thought about it, but tree branches are ideal to support a falling airframe. You have the wings and fuselage, plus the control surfaces on the plane. They match perfectly with the V-shaped branch structure. It gets stuck perfectly. Even if one branch should release the plane the next one will hold it again.

I climbed up, held myself between two bigger branches with both legs and arms. I used my third/fourth arm to pick a branch and try to push the plane from the V-spaked deadlock. Sometimes it felt so that even an optopus would need more arms there…

HaBoRC came with the solution, he found a longer stick that I could use from the ground to push the plane from the branches. It suffered almost no damage. A bit of dent on the leading edge, a bit of scratch from my recovery action. No more. It is a sturdy little plane this.

I have got my lection now. Fewer loops, fewer idiotic proximity flight with trees involved in the future. More respect.

I think I need to optimize my camera use. The hat cam v2 works perfect, the only problem is that I had the hat oriented too much to the ground. So almost no action is visible there. And since I have more battery time on the plane the small cameras cannot work so long. I need to extend their life somehow.

Please find my recording here. I have a spectacular Google Earth intro, zooming from Space to Arendal. Funny 🙂

Towards the end you may find some decent flying from HaBoRC even.

Best regards,

Sir Crash a Lot

Hello!

The title gives away already what will happen during this flight. September 2010 it is.

I had some simulator training sessions, wanted to do nose-in hovering finally. I did not succeed with it yet, with Lama I could do that but on CopterX I had some reluctant feeling about full nose-in hover. In simulator I could do it. However I neglected the golden rule. Simulator is approximately 2x easier than real flying. As I could just do simulator hovering I did not have the necessary margin for real flight safety. I paid the price for this, you can see later in my video.

I friend of mine joined me this time and we drove to my usual flying place. However it was too much wind there, I did not dare nose-in there. Chickened in, like McFly in Back to the Future. We moved location to a shooting range. There it was less wind, at least we hoped for it.

At 3:50 I do my first nose-in hover. You can observe that upon turning out from it I lose some altitude. I did not pay attention to that at that time, however this turned out to be a crucial part of my crash later.

At 4:25 my second nose-in happens. Great feeling, but I am way too scared to enjoy it really 🙂

Upon turning out I lose altitude again and during rudder input have some cyclic as well. Two pilot errors at same time is way too much, I crash my helicopter. I crashed lot of times with Lama but this time I can see that the consequences are more severe. This bird will not fly for some weeks.

At 4:55 I disconnect battery. This is good to do first, so you can avoid any injury. If you have the heli in your hands and check the damage and the throttle stick is activated you can get serious injury. Disconnect battery first. Depending on impact magnitude it might be good idea to have the battery some meters away of you. Li-Po can be dangerous if damaged in crash.

Main rotor is “done” more or less, mechanism got a big slap. Flybar is bent. At first I thought that main gear got stripped but later I discovered that electric motor moved forward in its slot holes and main gear survived due to this. Very rare.

I bent the main axle slightly, I think that this is a part that sacrifices itself in most of crashes.

Both front servos died in the crash, plastic cogs stripped inside servo mechanism.

I even broke the landing stip pipe. It is quite weak, almost elastic so that it can take up energy in a harsh landing. This impact was too much, the front section broke off.

From 6:47 you can see my detailed damage assessment.

Later I started to take apart my heli. I wanted to salvage those parts that are still fine. Unfortunately I faced some difficult challenge here.  To be able to salvage rear cyclic servo and tail gear drive I wanted to take apart two sides of the main frame. And here I faced problem. There are M2 bolts on heli, very tiny cross-recessed ones. Material quality is very low. When I tried to untighten them with my jewel screwdriver I just destroyed the head. I tried with other screwdrivers, did not succeed. I suspected that Loctite 243 threadlock was too strong or I did apply too much of it. I ended up with destroyed screw heads and the frame still in one piece.

I tried with a heat gun even. According to specifications Loctite eases up if temperature is applied. Not in my case, the frame was stuck. So I give up on it.

At this point I was not really sure if I will build a new heli. During flying helicopter I realized that I am more and more interested in FPV rather than helicopters specifically. So I suspend my helicopter activities temporary and face new endeavours. I found another platform that support FPV in a much better way, I am going to try airplanes now.

Best regards,

Sir Crash a Lot

Hello!

We travel in time, this time it is October of 2009. I just bought my Lama in September, so with total lack of experience I bravely started indoor flight exercises. And to be able to reconstruct my mistakes I tried to record as much as possible. The other reason for recording is to show off my skills on Youtube. What skills 🙂

Maybe it is time to tell about my recording platform. Calling it recording platform is maybe an overkill. I use my camera tripod, an older Manfrotto 190DB tripod that is similar to this one.

As a camera I use my wifes small digital camera, a point&shoot category Fuji F480 camera. It can record 320×240 pixel clips with 30 fps. Not a very capable camcorder, however it features an equivalent focal length of 28 mm in wide setting. This is good for indoor shots. As long as I don’t have anything better I use this camera. It gives nice recording if it has enough light, outdoor shots are quite nice.

Back to Lama flight. I tried to improve my skills and learn how to hover. This looks the more basic thing but is also the most difficult. It requires to find the perfect balance between forces acting on the helicopter. Even if the heli is stationary it requires constant control input.

What control inputs do we talk about?

There are 3 main control items on a helicopter. You have cyclic control, this tilts and banks the heli in all directions along horizontal plane. Then you have collective control, this is height basically. To complete you have pedals for controlling yaw.

On a helicopter whatever you do with one control all (!) other controls need some complementary input. Let’s say that you want to just go forward from hovering. First instinct would be to press forward cyclic and hope for good luck. This will result in the heli banking forward, then loosing altitude gently while it picks up speed in forward flight.

If you don’t want to lose altitude (for instance there are trees or houses around) you want to “get more engine power” and add some collective. Let’s assume that the engine control compensates for this action and we don’t consider now engine RPM. So you add some collective to compensate for height loss as you transition from hover to forward flight. We would think that this is perfectly okay, we have the heli under control.

But we have to cope with yaw control. As the main rotor rotates it generates torque that needs some countering force. Tail rotor does this, it counters torque coming from main rotor. As the RPM of main rotor changes we need to adjust what amount of thrust we generate with tail rotor, otherwise the helicopter will start to rotate along its Z-axis.

I think a visual illustration makes it much easier. Mikey’s RC has several great tutorials.

A good tutorial from Nightflyyer.

and

As I started with a simple coaxial heli I had little easier, the behaviour of a coaxial heli is much different of a collective-pitch helicopter. To illustrate how they fly I could say the following. A coaxial heli is more like “hanging” on its rotors, it always want to return back to vertical. A collective-pitch helicopter is more like “balancing” on top of an invisible air cylinder, it tries to “fall off” this cylinder, tries to escape balance all time long.

As a beginner coaxial is more practical. You don’t really have to care about maintaining the helicopter in the air, you can concentrate on flying it.

How difficult it can be after all?

It is still quite difficult. Even though that it is stable in flight, you are still drifting around in air. If you start to fly forward it is drifting on an invisible cushion of air. If you want to stop forward flight you have to decrease speed and try to stop. If you give too much input you will drift backwards. And there is always some amount of side movement, that you have to keep track of.

For me flying was very challenging and a lot of fun. I managed to find the right balance of challenge and excitement, I could still enjoy flying and get the blast of challenge that pushed me towards exploring more.

Here is how I managed.

You might ask some question. Like why do I slam the heli to the table? Why do I land so poor?

To answer this I have to refer to my inexperience and to ground effect. When you are flying low with a helicopter you gain lift compared to flying higher. Approximately at a height of rotor diameter this starts to be noticeable. As you get into this ground effect height you have to decrease throttle to maintain altitude. When you get above this height you have to add some throttle to have same altitude. If you are inexperienced you can have same problem as me, you just cannot handle throttle as needed and get into some oscillation of height. Practice helps.

At the end of the clip I crash even. This was my first crash being recorded. Some explanation here as well. When you crash a fixed-pitch helicopter (or you can see that crash is imminent) it is actually better to take away throttle and just let it fall down than trying to save it and max the throttle. This might sound crazy but is true.

On a fixed-pitch helicopter you have very basic rotor head, very little amount of moving parts. They are quite durable and easy to fix.

A collective-pitch rotor head looks more complicated.

If you crash the rotating blades struck some object and cannot rotate any more. If you add throttle during this the motor still tries to rotate them but they are blocked so something will let go. Either the blades crack and/or the motor burns down (or you crack some cogs). As these helis are so durable crashing from 1 meter height will probably not cause any major damage.

In my case the flybar weight popped out of its place, this can be popped back and I was ready to fly again.

Later I will tell about collective-pitch helicopters, crashing is totally different there. Yes, I will crash 🙂

Best regards,

Sir Crash a Lot