Archive for January, 2011


Hello!

I had some brainstorming on which airplane shall I begin with and convinced myself that the collective wisdom on the Internet could be right and I shall start with an Easystar from Multiplex.

As I am a methodic person I have my methods, of course πŸ™‚

First I did some research on which parts do I need in extra. Also checked which upgrades shall I perform. I had in my mind FPV, this is driving some parameters that influence my choice of parts.

I narrowed down my criterion for the following items.

– brushless motor for increased payload (due to FPV)

– ailerons for more control

– simple OSD for battery control and RSSI display

What do these points mean?

Well, brushless motors are giving you much more power at almost same weight. They require a speed controller that controls the motor. In the end you receive unseen power compared to older type brushed motors. In my case this is actually needed, since I am going to mount FPV gear to the plane and this means more weight and more drag.

Just for reference. A brushed motor glider has difficulties staying in the air and climb. A brushless glider can climb at approximately 70 degrees. When you have FPV gear on board you need more thrust. And more power (in this case) does not hurt.

Second point is ailerons. Easystar uses only rudder by default. For me this sounds like steering a car only with braking on one side. It does work for tanks, nevertheless I find this limiting. So I will add ailerons. How? There are several options for this.

You can cut out aileron control surface on your own and hinge it somehow. You can either use some tape as a hinge or even get real hinges. I went for this latter. Bought Du-Bro hinges.

Other question is to how to do servo layout. As Easystar does not have any aileron by default you don’t get any pre-made allocation for them. But with a sharp knife and some love you can make wonders and “machine out” some foam from the wings. Or even the fuselage. Depending on how do you want to place your servos. The linkage will be different but not impossible. I am still investigating this, so more details to come later on aileron modification.

Third point is OSD or On-Screen Display at full length. I plan to build FPV equipment at a later stage. However Easystar build is meant to do so that you glue together two halves of fuselage. So you need to insert all components prior to gluing. Of course it is not impossible to cut it out later but I would like to have a clean build. We shall see how I manage, though.

Back to OSD. I plan to build in a Simple OSD from Flytron. What I need from its capabilities in first place is that it can monitor 2 batteries and display RSSI even. Monitoring batteries is quite good option. Since I plan to glide with the plane the classical time-based estimation of remaining battery capacity does not really work. Other important factor is RSSI. If you fly FPV you got to know how well radio signals reach your receiver. If you fly out of range you can lose your plane. If you can have RSSI gauge you can see when to turn back. Added safety.

For the sake of battery readings I will need current sensors. 2 of them. One for the plane battery and one for the FPV battery. For interference reasons it is better to have 2 batteries.

For the rest I will proceed as RC Explorer did in his build tutorial.

As you can see he is stiffening up the plane with carbon-fibre rods, pipes and strips. I will do the same, this will give better handling in turns with G-load.

I expect to have some of these items arrive this week. Very exciting.

Best regards,

Sir Crash a Lot

 

 

 

 

 

 

 

 

 

 

 

 

 

Advertisements

What to have for FPV?

Hello!

This is my first post that actually happens in present time. So far I told stories of my adventures with helicopters. I got into FPV and understood after a while that helicopters are not really suitable for this task. It is not impossible as Muni86 can demonstrate.

As I understand he is something like 10x more talented with his helicopter as I am so far. I need to find an aircraft that I can pilot well and provides a more manageable platform for FPV. I tried to think outside of the box and started to read again.

I found some FPV homepages and started to browse them. I would recommend to check out.

RC Explorer

FPV-Community

RangeVideo

At first I was overwhelmed by the amount of information on these sites. But with some processing I could find a trail that looked possible for me.

A very popular airplane for beginners and FPV pilots is Multiplex Easystar.

It has a wingspan of 1.3-meters. This plane is somewhere between a glider and a motor plane. It can glide quite well, if you know how to use upstream you can stay up in the air for long-long time.

What is important for me is that it is a very kind airplane, a great introduction into airplane flight for a beginner.

Another factor is its moddability. People created a lot of possible modifications for this plane. Some of these are offered as a ready pack, others you can do yourself. Like adding ailerons. Or more powerful electric motor.

A good summary of mods can be found here (petleh82 made it)

RC Explorer has a great review of this plane. If you check out his FPV videos you can see that this plane is present during many clips.

This plane is possible to glide, this has several advantages. First you spare energy and can have longer flights. Second you eliminate almost all vibrations, since the motor is not spinning. Do you remember my vibration issues with helicopter? These are going to be removed alltogether when gliding. A video from Intense Tobak, he flies an Easyglider (1.8-meters).

I colleague of mine has ordered another Multiplex plane, it is called Twinstar. It is not much a glider, more like a motor plane.

This plane has ailerons by default, you don’t need to modify it. However due to the gliding question I stick to Easystar instead. I am such a beginner that it is better to start with a beginner plane.

Easystar is going to be a good sample of both worlds, (motor and glider) so I can decide which direction I shall continue. Right now it feels like that gliding it is. I am amazed of the perspective of using the winds only as a propellant force. A nice upstream above a field in summer can give me almost infinit flight time. For safety I still have the motor. I like this combo.

My dream glider right now is Cularis from Multiplex. This has 2.6-meters wingspan, a different class already. Just look at it:

Isn’t it beautiful? πŸ™‚

Now I am doing studies to get some depth in FPV. There is a lot of reviews, mod listings and videos of how you can start. I already posted this link but it is so good that I do it again.

FPV Starting guide from RC Explorer. I am going to do a listing of what do I plan to order. Hopefully it will help those that are in same shoes as I am.

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 πŸ™‚

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.Β  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!

Mid July, 2010 it is.

I had some maintenance beyond the normal checking procedure before each flight. Normally I go through connections, bolts and check if something is loose. Cable clamps are tight, no connectors get undone. It is good to do this, otherwise you don’t get any warning and crash.

After every 10th flight it is recommended to do some extra work, lubricate rotating parts, check belt tension. I did that, no problems were found.

We spent some days at a friend and his wife in HindΓ₯s. Since he is interested in RC I took my heli. We did some flying in his yard and did some roof checking. I hovered around the house and tried to capture how the tiles are sitting on the roof. No problems were found.

Hovering was pretty challenging. As you get higher the more wind you get. Even if it feels very calm on surface level, at 10 meters you get some wind anyhow.

Hovering just above my head was tricky. I could not really see if the heli starts to bank, I could only track that it starts to drift. Then it is late, I lose maybe 1/2 second reaction time. Tricky.

The biggest problem was however vegetation. Huge trees around the house, a lot of branches which are like death traps for a heli.

Instead of hatcam we recorded with a mobile phone. Sony Ericsson X10 Mini Pro it is. Quite good quality for a phone, mine records much worse video.

For second half of the clip I skipped tail camera, so you get almost real FPV this time. I like FPV more and more as I do it.

Best regards,

Sir Crash a Lot

 

 

Hello!

July 2010 it is. I had my first triple camera flight. What needed a fix:

– better camera mounting

– vibrations

– nicer frame layout

First point was easy to fix. I put more attention to “aim” the cameras. These cameras had focal length that provides normal field-of-view, they are not really wide-angle. So aiming them well is important.

Second point was more tricky. I made some research and found out that you need a combined solution. You have to dampen vibrations and at same time (!) have a stiff connection. Best is to have something relative soft material under your camera and have some clamping that gives firm and stiff connection. If you would only have the soft part you will have a flimsy mounting, just as I had last time.

At this time I increased the size of my velcro tapes, this alone stiffened up a lot. I could not use plastic clamps as I only had short ones at that time.

At 1:40 I almost crash into myself. I get some sudden wind gust that pushes my heli at me. I could correct this move but it got uncomfortably close. Those blades spin at something like 2000/min so it is good to avoid them.

This time I could do much better shots of the area, quite nice weather and scenery.

At the end of the clip you can even see some special event, let it be a surprise πŸ™‚

Please find some extra material from same flight here. I chase a motorbike (only a bit) and follow a car.

Best regards,

Sir Crash a Lot

Hello!

End of June 2010 it is. I bought 2 keyholder cameras recently and tried them out on my helicopter. Weather played with, nice sunshine and not much wind.

I wanted to create a picture-in-picture experience in my video, when you can see simultaneously both onboard cameras and my hatcam.

I had one camera on the tail in portrait orientation. This showed most of the helicopter. The other camera was fixed under the canopy upside down. It doesn’t matter which orientation I used, I could set them upright later in video processing. Third frame was my hatcam. I used adhesive velcro tape to fix my cameras.

Quickly after starting the motor I could see that I have a problem. Vibration. The tail camera was badly influenced by this. The picture got wobbly, all sort of wavy interference disturbs the footage. As far as I understand CCD cameras record line-by-line. So if you have some quick moving object in the frame it gets bent or tapered. Like my rotor blades look like banana as the sensor cannot read so quick as they rotate. Vibration becomes very quick movement, video compression just gets confused by this and you get this wavy image.

If you read this guide of RC Explorer you can see how CMOS and CCD cameras handle vibration. See some comparison examples here even.

At this point I still used the stock slow memory cards, so there is lag problem on top of vibration issues.

I tried to make some shots of the bay close to us. It looks great from the air, however all this shaking and wavy image ruins the experience somewhat. I see the light at the end of the tunnel but we are not there yet…

This setup gave me a lot of excitement, having those cameras on the heli is very promising. I need to sort out vibration issues. Started to read a lot about it and found the solution actually. More of this in next post.

Best regards,

Sir Crash a Lot

Hello!

Earlier I posted about basics of FPV and my quest for finding a camera small enough to be carried on my helicopter. I did not really get to the very moment of purchasing. And actually that was a good thing. Why? Because I found a much better solution.

I bought some keychain cameras from Hobbycity. They are not the best, rather medium quality among all those cheap keyholder (keychain) cameras.

A good type should give you footage like this. Notice the yellow timestamp. (video of salvix001)

This camera sets audio gain automatically, has quite okay metering and color rendition for such a small and cheap device. We are talking under 20 USD just to put things in perspective.

The camera that I bought was like you can see on following clip.

Notice the white timestamp, the jerky movement (lags in video stream, the footage “jumps”), the different colour rendition. Maybe it is not so noticeable now as I profit from bright sunshine while the “good” camera is indoors but my camera has worse colours in comparison. Later I learned that mine does not compensate microphone gain for exterior noise level.

I was amazed by the possibility of recording from the helicopter, but was somewhat unhappy about the lagging. Nevertheless this was possible to cure. I read on Hobbycity forums that with higher speed memory cards this is no problem. I bought my 2 cameras with memory cards, at that time you could only get them with memory card. Those cards were very low spec.

I try to give you some crash course on memory cards. Probably this will be obsolete in short time as computers evolve with the speed of sound, standards come and go all the time. So please consider this valid at the time of being written and maybe 1 year ahead.

These cameras use MicroSD cards, another name is Transflash. You usually find these in mobile phones.Β  They are smaller than SD (or Secure Digital) cards, much smaller indeed. What I was looking for is actually High Speed Micro SD or MicroSDHC cards. These have same form factor as MicroSD but have more speed. The one that I was going for was Class 6 speed level. It sounds like sci-fi to me.

With such a card (Class 6 speed Micro SD HC at 4 gigabytes capacity) I managed to get video without lag.

This was already acceptable for me. I did not know yet of the audio problem (the lack of gain compensation), video was okay. I tried this setup on CopterX on my next flight. Stay tuned for this coming post.

Best regards,

Sir Crash a Lot

Hello!

June 2010 it is. My 8th flight was a bit unusual. I flew just as I did earlier but did not have any recording device at my disposal. My wife took her camera on a business trip and left me without any video recording device. Can’t really blame her, it is her camera after all πŸ™‚

Anyhow I came up with a plan. What if I “fake” my flying in simulator. These modern simulators provide such nice graphics that probably only the eagle-eyed viewers will notice.

Please see my flight or my visual story of my flight more likely.

This is a short post, since the video tells everything that happened. I learned a lot this time as well, was hoping to be able to do more advanced flying soon.

Best regards,

Sir Crash a Lot

Hello!

My 7th flight took place end of May 2010.

7 is a nice prime number, I wanted to do something special. I am a big fan of Isaac Asimov sci-fi books. He was a great writer, his robotic novels are my all-time favourites. So why not have robotic commentaries in my video?

Since we are talking sci-fi I have to mention Arthur C. Clarke as well. The movie based on his novel 2001: A Space Odyssey is also my favourite. I tried to incorporate a bit of that into my clip.

I watched some Nightflyyer videos. He told story of RC flying in early times, a control method of “U-control”. If you watch the videos you can see quickly how it works. You hold a U-shaped object and control the model with strings or steel cables. You will stand at one point and fly around yourself while you rotate together with the model flying in circles.

He even converted a modern electric model to U-control.

I think you have guessed how I will fly. Yes, around myself. But instead of strings I use the Marconi-magic: radio.

This gave me good possibility to practice forward flight without getting very far away with the model. I tried to practice slow and smooth turning. The slower the more difficult it will be. Flying fast is more easy actually since your helicopter will become more and more like an airplane. When you are close to hovering difficulty level will increase.

When the heli is banked and turns and you can see your own rotor blades (rotor disc) from slightly above then you feel that it is worth it. Great sight, lot of fun πŸ™‚

Best regards,

Sir Crash a Lot

Hello!

May 2010 it is. I practice flying, try to improve skills.

I am still reluctant to turn my heli 180 degrees aspect angle, this means that I still cannot do nose-in hovering. I try to practice 90 degrees aspect angle, when one side of my heli is pointing at me. This works at some extent.

In this video I try to do nice turns, when I coordinate rudder and cyclic during my turn. Aim is to turn so that I obtain a fluid movement, a nice dynamic turn and transition to forward flight. Not so easy.

I tried a 360 turn as well. From hover I push rudder and spin it around. You can observe that during this I am unable to compensate for hovering and my heli starts to drift away. This demonstrates fine how much input is needed for a basic hover. As soon as there is no compensation the heli drifts away. Once I do the spin slightly slower and I drift quite away.

Once I nearly crash, a person is coming into the workshop and asks me a question. I look at him for 2 seconds (more like a glance) and during this time I almost smash my heli into the concrete. Constant awareness is needed to fly. A good lesson for me.

Best regards,

Sir Crash a Lot