|
|
Since about 2002 I have been using a iPaQ [1] for taking notes while on the move. I have a pair of H3950 iPaQs that were given to me for the purpose of some software development work.
As modern mobile phones have telephony as a small part of their feature set I think it’s worth comparing a 2002 iPaQ with a 2009 mobile phone in terms of the note taking functionality.
I have just got myself an LG U990 “Viewty” mobile phone [2]. It has a screen resolution of 240*320 which is the highest resolution that is remotely common for a mobile phone – and the same resolution as my 2002 model iPaQ. The LG KC910 “Renoir” has a resolution of 240*400 and seems to be the only phone that my carrier provides which has a higher resolution. The iPhone [3] has a resolution of 480*320. So it seems that the most expensive modern mobile phone that is available in Australia has a screen resolution that is only twice that of a 2002 PDA. I believe that in Japan you could buy a PDA with a higher resolution than 240*320 in 2002.
My iPaQ is running Linux, so I can do whatever I want with it. I have a bar at the bottom of the screen with icons to launch, I configure it with the programs that I need most often and they are always one click away. While with my mobile phone I always have two large icons for paid services from my telco and I can’t add icons for the things that I want.
 
My iPaQ has a virtual keyboard that can be displayed in portrait or landscape mode. The above pictures show it in the portrait mode which allows the greatest area of screen space for text. The landscape mode is good for entering long lines of text even though the total number of words that can be displayed on screen is smaller.
The size of my iPaQ is 134mm in height, between 77 and 84mm in width (it tapers) and 15.9mm thick without it’s protective sleeve. The protective sleeve (shown in the second picture) adds about another 5mm to the width and thickness.
My iPaQ is 1.76* the volume of my Viewty phone and at 184g vs 112g is 1.64* the mass. With it’s sleeve on it is about 2.4* the volume. It’s larger but with the sleeve it’s a lot more solid, a touch-screen is very fragile so putting a touch-screen device in your back pocket without a sleeve is not a viable option.
So I now own a mobile phone that has more storage, RAM, and CPU power than my iPaQ, but is less useful for the basic task of writing small documents and seems to have no facility for drawing diagrams. Most recent mobile phones have the ability to record voice (my Viewty can store 34 hours on it’s internal storage and supports mini-SD cards for extra storage). But my Viewty lacks the ability to pause voice recording so if I wanted a series of notes during a meeting I would get a series of short voice recordings rather than a single file with many items. The todo list is also fairly poor in the Viewty, so even disregarding the poor keyboard on the touch-screen it would compare badly to the iPaQ.
So it seems that an iPaQ that is almost seven years old when running Linux and the GPE Palmtop Environment [4] with with default configuration handily beats one of the latest and greatest mobile phones for all areas of common functionality.
If the Viewty had it’s source code available I would be tempted to contribute some patches (even if it was not free software).
Finally, before someone suggests an Android [5], Greenphone [6] or other phone that’s relatively open and programmable, I wanted a phone that had a good camera (by phone standards) and came essentially for free on an affordable contract. Maybe in two years time (when my current contract ends) there will be such a phone on offer. Mobile phones aren’t THAT important to me, so while I would like to encourage the development of open telephony platforms it’s a much lower priority than about a dozen free software projects.
I expect that in the future something like an Android will become a great mobile phone with great PDA functionality. But for the moment I’ll use an iPaQ and a Viewty.
One annoying thing that happens regularly is “Planet Flooding”. This is when one of the many blogs that is syndicated by a public Planet installation changes it’s time stamps and has 10 or more old posts appear as new. It’s doubly annoying when the blogger in question knows about the problem.
Planet Flooding is easy to solve. If you are changing your blogging software or doing something else that may result in old posts appearing to be new then all you have to do is configure your blog to include a small number of posts (maybe two or three) in the RSS feed. Seeing two old posts re-appearing plus a new post explaining it is not going to annoy anyone.
If you run a Planet (or Venus) installation then configure it to have a maximum number of posts per feed. For a Planet that syndicates feeds from a number of individuals and only includes a few days of traffic (which is probably a category that covers most Planets) there is no need for more than four items per feed.
For a severe case of Planet flooding (EG posts which always appear as being the newest and are therefore at the top of the list) the thing to do is to immediately remove the feed until the problem is fixed. Allowing a broken blog configuration to annoy other people is not doing any favors for the blogger in question, it simply drives people to filter the Planet to exclude the articles by that blogger. Yes it does take some work to adjust the configuration of the Planet, but that is surely no more work than replying to email rejecting requests for the configuration to be adjusted.
The first aim of running a blog or a Planet should be to make it readable, Planet flooding breaks this for the Planet and for the blogger who caused it. It is a technical problem and needs a technical solution (which can be temporarily removing the blog from the Planet syndication list).
I have just had a need to install packages from Debian-Multimedia.org to correctly play .3gp files from my mobile phone (the stock Mplayer in Debian would not play the sound).
As part of getting this to work in a way that I like I rebuilt some packages so that shared objects would not demand an executable stack and added them to My SE Linux Etch repository [1]. The liblzo2-2 package is in Debian so I filed bug report #511479 against it. Not that I expect it to be fixed for Etch now that Lenny is about to be released. But it’s good to have the data in the bug tracking system for the benefit of all interested people.
The lame and xvidcore packages are only in the Debian Multimedia archive. I’ve sent email to the maintainer with patches. Not sure if he will accept them (again it’s not a good time for filing bug reports about Etch), but there’s no harm in sending them in.
The lame package also required execmod access, but I don’t have enough time to devote to this to fix it. For background information about execmod see my previous post [2].
See my previous post about executable stacks for more background information [3].
The next thing to do is to test this out in Lenny, hopefully I’ll get time to work on this tomorrow.
I have never felt inclined to create content for Youtube due to the low resolution of the display and the fact that only one format is supported (Flash which is totally non-free).
The existence of blip.tv has inspired my interest in creating videos for distribution on the net. blip.tv has higher resolution than Youtube and supports multiple formats. Currently the multiple format support is limited to allowing users to upload whatever they want and then Flash (FLV) will be provided for download in addition to the original file(s). So for example I could upload MPEG4 and Quicktime movie files for the same content which would result in three download options (MPG, MOV, and FLV). It would be nice if they could support more formats as the default (maybe support transcoding to OGG), but it’s certainly a lot better than Youtube.
So the question then is how to create content. One option that I plan to use is Istanbul – the GNOME desktop session recorder [1]. It will record everything that happens on the desktop (or a section of the desktop) to an OGG file while also optionally recording audio input. This allows the creation of tutorials for performing various tasks on the computer.
Another option is to do animation, either completely computer generated or by combining a set of JPEG files into an animation file. This doesn’t interest me to the degree necessary to make me invest the necessary time.
But the most common way of producing video content is via a camera. So the question becomes what camera to get.
My current camera is a Sony Cyber-shot DSC-T5 [2]. It is a 5.1 mega-pixel camera with 3* optical zoom and supports 640*480 resolution movies at up to 30 fps. The quality of photos and video that it produces seems to be quite good, I don’t have any particular problem with the camera that I want to address by purchasing a new one, so a major aim of buying a new camera was the fact that it’s a few years old and something better must be available at a low price!
I asked for advice about this on my local LUG mailing list. One piece of advice that was offered by several people was to use a Digital Video camera with Firewire output to record quality video. They spoke about common digital cameras as “point and shoot” with the acronym “P&S” – which seems to be used as a term of abuse by people who are really into cameras. If using a DV camera with Firewire support (which is apparently a really important feature) then apparently Kino [4] is the program to use to capture the raw video data.
While the advice in regard to a digital video camera sounds good I’m not going to take it. Such DV cameras start at about $300 and appear to be physically larger. While a larger camera (with a larger lens) will give better quality pictures and higher frame rates with lower levels of ambient light I am planning to do my serious video recording in a controlled environment with reasonable lighting. Really I’m not THAT serious about video recording, so I don’t plan to spend $300 or more – I’ll accept the lower quality as a trade-off for lower price and greater convenience.
I have seen an advert for a camera described as a DC-777 at a good price from DirectBuy.com.au [3]. The camera in question is one that has no reviews anywhere on the net and seems to be a re-badged version of someone else’s camera. It initially sounded quite good with 11mega-pixel resolution, but the fine print shows that it has a 7MP CCD and uses interpolation to get a higher resolution. Also the movie capability is 640*480 at 30fps (the same as my Sony). So the benefit of using the DC-777 would be the rotating display which can face the same direction as the lens thus allowing someone who is making a video of themself to see what they are creating. This doesn’t seem to be $200 worth of benefit, but the camera might be a reasonable deal for someone who doesn’t already have a decent “P&S” digital camera.
Another interesting piece of advice I received from my local LUG was that the amount of time taken to get a good image (which determines the shutter speed on a good camera or the maximum frame rate for video) is determined in part by the size of the elements in the CCD. So with all other things being equal a camera that supports higher resolution will require longer exposure. For my use the benefit of higher resolution photos is often for the purpose of cropping pictures of objects that were too far away to allow completely zooming in. 3* optical zoom (as implemented in my current camera) is a limit when photographing objects that are far away in good light conditions (in poor light it’s often a factor of the lens size).
In the past when looking at digital cameras I would make the resolution of the picture the prime criteria – with the idea that bigger is better. But now it seems that the smart thing to do is to make optical zoom the prime criteria for general purpose camera use. Also having a larger lens is a significant benefit, but as the overall volume of the camera is going to be roughly proportional to the radius of the lens cubed it can’t get that big without some serious compromises on portability.
Obviously an SLR [5] offers significant quality benefits. But if you are unwilling to spend so much money a good result can be obtained by what are sometimes called “Big Zoom Digital” cameras. These are cameras with a body shape that resembles a SLR, they vary in size between the P&S cameras and SLRs, and have fixed lenses that are significantly larger than those of P&S cameras. I gave such a camera to a relative for Christmas and I was very impressed by the quality of pictures and movies that it produced. I chose a Kodak camera with 12* optical zoom which was quite impressive (unfortunately the 15* model had sold out). One of the benefits of a Big Zoom Digital camera over a DSLR is that as there is no option to replace the lens there is also no possibility to get dust inside the camera (which is apparently a problem with SLR cameras).
For my own use I plan to stick with my Sony Cybershot. I can’t get anything significantly better for an amount of money that I am prepared to spend, and I also don’t really want a larger camera. So I think I’ll buy a tripod (or maybe two tripods of different sizes), that should deliver a real benefit for my photography without costing much.
Update: One thing I forgot to mention is the film speed rating (AKA the “ISO” number) [6]. A higher ISO number means that the camera can take faster pictures in less light. The Wikipedia page reports that camera manufacturers are permitted to interpret the ISO scheme in several different ways, so they can essentially just make stuff up. Probably the best that can be said for the ISO number is that any camera which advertises it is aimed at more serious users and is therefore likely to be of higher quality. I’m sure that if I was to spend $700 or more then I would get a camera with an advertised ISO number that actually means something, but I don’t have any plans to ever do that.
Matt made a good comment that the quality of the glass matters. For an SLR you can consider the lens quality independently of the quality of the rest of the camera. But for cheap cameras it’s just a matter of the entire package.
Tim (a member of my local LUG) writes about some observations he has made of a nearby river and speculates on a tidal bore-like phenomenon [1].
One thing that surprised me was how short the list was on the Tidal Bore Wikipedia page [2], and the fact that is it missing an entry for Tidal River at Wilson’s Promontory [3] (where my family often spent the Christmas holidays when I was young).
Some of the tidal bores are described as having a wave as high as two meters, Tidal River is not so impressive, my observation was that during the 80’s it was about 40cm near the mouth of the river. The area near the river mouth had many bends when I last saw it which absorbed some of the energy of the wave (but I expect that the river changes course constantly so it might be straight from time to time).
On one occasion I River Surfed [4] about 500 meters upstream at Tidal River on a surf-mat (an inflatable surf-board).
I have searched for research into this issue, the Tidal Bore Research Society [5] seems to just maintain a list of tidal bores and not do any real research. Pierre Lubin, Stephane Glockner, and Hubert Chanson published a paper titled “Numerical simulation of turbulence generated by a tidal bore” [6]. Hubert Chanson at the University of Queensland has written an interesting paper titled “Physical Modelling of the Flow Field in an Undular Tidal Bore” [7]. Hubert seems to have published more papers related to tidal bores than anyone else (or at least more papers that are publicly accessible).
A teacher in Arizona steals Linux CDs from a student and then accuses a Linux distributor of being a criminal [1]. Even though she had used Linux in the past she didn’t believe that software was free. Of course that implies that in the past she had performed actions that she believed were criminal.
Neat Little Mac Apps interviews Marshall Kirk McKusick – he describes how the BSD Daemon logo was designed and one of his most significant bugs [2].
OurDelta.org offers MySQL builds with some extra features and support [3]. I was recommended to use their builds by Arjen Lentz of Open Query [4], as one of my clients is going to use the services of Open Query it seems best to use the Our Delta builds if only to get better support from Open Query. The extra features in the Our Delta builds seem interesting, but I’m not sure that my client needs any of them at this time.
The Global Guerilla blog reports on a man who single-handedly invaded the most heavily guarded power station in Britain and shut it down to protest against new coal power stations [5]. The entire blog is worth reading, the author has a lot of interesting ideas.
PhpMyVisites is a free web site analytics system that competes with Google Analytics [6]. I haven’t implemented it yet, but it looks promising. It seems that PhpMyVisites is not being updated any more (not even security updates) and the replacement is Piwik [11].
Andrew Lahde was a fund manager who made significant amounts of money by betting on the inability of US mortgagees to repay their debts, he wrote an interesting goodbye letter (Telegraph.co.uk) [7]. He now has a Wikipedia page which gives some interesting background to his career [8]. An Employee of the Financial Times is famous for flaming Andrew [9], I have submitted a comment pointing out that being famous for flaming someone who is more successful than yourself is nothing to be proud of and suggesting that he advocate his own political views when criticising those of others – I doubt that it will get through moderation. It’s a pity that Andrew doesn’t have a blog, I would like to read more from him.
At CCC a paper by Alexander Sotirov, Marc Stevens, Jacob Appelbaum, Arjen Lenstra, David Molnar, Dag Arne Osvik, and Benne de Weger on how to crack the PKI infrastructure used for SSL signing was presented [10]. The root cause is some CAs still using MD5 even though it was broken a long time ago.
Updated to note that Piwik is the replacement for PhpMyVisites.
Mike writes about his work in using namespaces on Linux [1]. In 2006 I presented a paper titled “Polyinstantiation of directories in an SE Linux system” about this at the SAGE-AU conference [2].
Newer versions of the code in question has been included in Debian/Lenny. So if you want to use namespaces for a login session on a Lenny system you can do the following:
mkdir /tmp-inst
chmod 0 /tmp-inst
echo “/tmp /tmp-inst/ user root” >> /etc/security/namespace.conf
echo “session required pam_namespace.so” >> /etc/pam.d/common-session
Then every user will have their own unique /tmp and be unable to mess with other users.
If you want to use the shared-subtrees facility to have mount commands which don’t affect /tmp be propagated to other sessions then you need to have the following commands run at boot (maybe from /etc/rc.local):
mount –make-shared /
mount –bind /tmp /tmp
mount –make-private /tmp
The functionality in pam_namespace.so to use the SE Linux security context to instantiate the directory seems broken in Lenny. I’ll write a patch for this shortly.
While my paper is not particularly useful as documentation of pam_namespace.so (things changed after I wrote it), it does cover the threats that you face in terms of hostile use of /tmp and how namespaces may be used to solve them.
It’s almost Christmas and time to buy scientific toys for children. Here are some random ideas, of course it’s probably too late for the online stores to deliver – but there’s always next year.
The MikroKopter is a kit helicopter based on four propellors (two rotating in each direction) and is capable of semi-autonomous flight while carrying a decent payload (such as a digital camera) [1]. The parts cost over E700 and the skill involved in assembling it is significant, but it would be an excellent present for anyone who is 14+. Of course the type of helicopter described in my previous post [2] is a much more affordable present and can be used by a young child.
The scitoys.com site has a good range of scientific toys for sale [3], they are assembled into kits.
The United Nuclear site has a huge range of chemical supplies and related things [4] that can be used for making some great science experiments and toys. They also have really detailed information about the potential hazards of the things that they sell (not that I was planning to buy Cesium or Uranium anyway). If buying exotic alloys elsewhere it’s probably a good idea to check the United Nuclear site for the hazard information (not all sites provide as much information as they should).
Professor Bunsen is an Australian site selling similar produces to SciToys [5]. The range is slightly different, and if you are in Australia then it’s safer to buy locally – there is a significant amount of stuff on the United Nuclear site that would be unlikely to pass Australian customs.
The Spirograph is a good way to introduce mathematical concepts to children [6], it would probably be a good present for children who’s parents are not interested in maths and science.
Lego [7] is always good, but there are also other similar products to consider. Meccano [8] is good for older children, but the ranges for younger children have some deficiencies (the 2+ stuff requires the finger strength of an adult to assemble all parts).
The Italian company Quercetti has some great products [9]. Unfortunately their web site is only in Italian and they have no links to sites in other countries/languages (they do have the names of some distributors who may have web sites). Their products includes a gears set (suitable for teaching children as young as 1yo) and a model car with an engine that has pistons moving inside a clear plastic case, a two-speed gearbox, and a fully functional differential (designed for 2yo+).
For more hands-on tasks that require supervision (not something that can go under a tree) one good option for ages 3+ is to disassemble a variety of computers and computer parts. CD-ROM drives are good because you can connect a 9V battery to the head assembly motor or the tray eject motor to make it work. Hard disks have insanely strong magnets inside them – don’t give two such magnets to a child.
A multi-meter is a great educational toy that can be used for many great experiements (as well as for practical tasks such as determining which battery of a set is flat) [10]. The parts from a hard disk can be used to demonstrate how a generator works (the mechanism to move the heads provides you with strong magnets and a coil that fits them). Note that an analogue meter is needed for such experiments as the amount of electricity generated is small and AC – a digital meter will average it out to zero (at least for the more affordable meters that I have used). It’s probably best to own both a digital meter and an analogue one, the minimum age for owning such a meter is probably about 10, the minimum age for using one with supervision is about 3.
An oscilloscope is a great educational toy [11], unfortunately they are quite expensive (Ebay seems to have nothing below about $450). They can be used for all sort of fun tasks such as measuring the speed of sound. The wikipedia page notes that you can get PC based Oscilloscopes (PCO) which are cheaper. I wonder if they have Linux support for such things…
The OLPC is a great computer for kids in developing countries [12]. They are now available in Australia [13].
For most children in first-world countries a second-hand laptop of a more traditional design is probably a better option. There are a significant number of old laptops gathering dust which can easily have Linux installed with a variety of educational software. Buying an OLPC on the “give one get one” deal costs $400US plus tax and shipping, while a second-hand laptop can be purchased for significantly less than that. While giving an OLPC to some random needy child is a good thing, as the person who gives a laptop locally is probably going to provide support for it there are some benefits to giving a regular laptop.
Conferences often have bags of random junk to give out to delegates, and trade shows always have lots of little toys with company logos on them. Such things are usually of little use – but children like them. Also the trinkets that computer companies give away are often educational. If you have a cupboard filled with such things then unloading them on some children is a good idea – of course you have to make sure that anything you give to young children can’t be swallowed and has no sharp points.
Hi, I’d like to send an email from a small domain that you’ve never heard of or from a big ISP that’s known for being slack about spam (*), I can’t send the mail to you because of your anti-spam measures. I think that this is unfair, it’s discrimination, and you are cutting off your nose to spite your face in rejecting my mail.
So please reconfigure your mail server now and accept more spam in your inbox, my message is important enough to justify the extra time you will spend manually deleting mail and the risk of accidentally deleting legitimate mail while deleting heaps of spam (I am in fact more important than you).
By not accepting my mail you are being an asshole. I only receive a dozen spam messages a day and I don’t mind it, without even knowing you or having bothered to do a web search to see how well your email address is known I’m sure that you don’t receive any more spam than me and therefore you too can turn off most anti-spam measures and manually sort through the spam.
You don’t really have a problem with spam, you are just paranoid, I’m sure that you installed your anti-spam measures before receiving any spam and then never bothered to check the hit rates.
My sys-admin knows that one of the DNSBLs has an old entry from when his server was broken, but he won’t request that it be removed – so you can change your server because my sys-admin doesn’t want to click on a URL that you sent him.
The RFC-ignorant.org service is used and run by ignorant people – I know this without even reading their web site to discover how it works.
The above is a summary of a number of complaints that I have received about my anti-spam measures. I’ve para-phrased them so that they make sense, I have not actually had someone directly say “I’m more important than you so you should just accept more spam”, but the implication is quite clear.
Now there are some legitimate reasons for requesting that anti-spam measures be reduced. In the distant past almost everyone had working reverse DNS entries which matched the forward entries and it was common to reject mail from systems that didn’t have valid DNS. Nowadays there are many big ISPs that delegate IP address space without permitting reverse DNS entries, and there are companies that have one department in charge of IP addresses (who don’t have a clue about reverse DNS) and another department running mail servers (who are cluefull). So the environment has changed to make reverse DNS checks a non-viable anti-spam measure. Requesting that people remove such checks is reasonable.
Anti-spam measures that attack innocent third parties are bad. Sending “warnings” about viruses has made no sense for many years as all modern viruses fake the sender address, an employee of one company once admitted to me that they were sending out anti-virus “warning” messages as a way of sending unsolicited advertising to random people (I reported them as a spam source). Some time ago on a routine upgrade of ClamAV I accidentally copied in a default configuration file that made it send such warnings – I was grateful when someone informed me of my mistake so that I could fix it. Challenge-response is another technology that causes harm to others. I think it makes a lot of sense for mailing lists (every modern list server will confirm subscription requests), while it does result in sending unwanted mail to innocent third parties (every time a new virus becomes prevalent I receive a number of confirmation messages from list servers), but it’s not something that I will use on a regular email account (but I am prepared to do paid work implementing CR for other people).
Requesting that manually implemented blocks be removed is quite reasonable. Occasionally I find that mail from one of my servers is blocked because a previous owner of the IP address space did bad things. In such a situation it is quite reasonable to provide an assurance that the new owner takes abuse issues seriously and to request that the block be removed.
Requesting that I make any change to my system without making a minimal effort to get your broken mail server fixed is totally unreasonable. If the system administrator is not prepared to click on a URL to get their system removed from a black-list or if the user is unwilling to report the problem to the sysadmin then I will probably be unwilling to make any change to my system. The only exceptions to this rule are for clients, colleagues, and for people who use mail services that are large and unresponsive to users (IE the users don’t directly pay). I recently made a white-list entry for a large European ISP that is used by a Debian Developer for their work, as the ISP is known to be unresponsive to requests and mail related to Debian work is important to me I added a white-list entry.
One thing I am planning to do is to document my anti-spam measures and then allow people the opportunity of suggesting new anti-spam measures that I haven’t tried yet if they want me to turn off any of my current protections.
(*) I’m not aware of any big ISP that takes strong measures against spamming customers and customers whose computers are trojaned. I am aware of one having done it in the past, but I suspect that they may have ceased doing so after their brush with bankruptcy. I suspect that many ISPs simply rate-limit their customers connections to the outbound mail relays and hope that they don’t get enough infected customers at any time to get themselves listed as a spam source.
I have just bought myself a toy helicopter. I had been tempted to buy one for a while and when I saw them on sale for $30 I couldn’t resist.
My helicopter is model FJ-702 from Flyor, it is controlled by infra-red and is designed for indoor use only. It seems that the trick to flying one is to control the rate of ascent and descent. If the helicopter rises too fast then it may bounce off the ceiling which results in it swaying uncontrollably and crash-landing. If it is allowed to descend too fast then it becomes impossible to slow the rate of descent, I suspect that this is the settling with power [2] problem that is documented in Wikipedia. The helicopter is very fragile, I broke one of the skids and part of the tail assembly before I learned how to control it properly. Probably the main thing to look for when buying a model helicopter is a solid design – some time after buying (and breaking) my helicopter I visited the shop which sold it and heard the owner advising other customers to buy the $45 model which is apparently more solid.
It seems that an ideal design would be a frame made of spring-steel (not to make it springy but to avoid it breaking when it hits). I recommend flying in a room with a carpeted floor, bouncing off a solid surface such as a wood floor will break a helicopter.
Controlling a helicopter is really difficult. The models that I have tried and seen demonstrated all have serious problems with unwanted rotation. My helicopter and the others I have seen have coaxial rotors to avoid rotation without a tail rotor. According to the Wikipedia page a lot of energy is used by a tail rotor [1], as there has been obvious difficulty in designing the helicopter with adequate power (in terms of the light and weak frame and the short battery life) it seems that they didn’t use the tail rotor design to save energy. It’s a pity that instead the designers couldn’t have skipped the flashing LEDs etc.
One strange thing is that one pair of blades can have their angle changed (which appears to be similar to the “semirigid” design shown on the wikipedia page). I’m not sure how increasing the angle of one blade while simultaneously decreasing the angle of it’s pair will do any good. I expect that this has something to do with the fact that the helicopter will rotate at different rates when under different amounts of vertical thrust. This incidentally makes it almost impossible to maneuver the craft. It has a tail rotor on a vertical axis to control forward and reverse movements, but the extreme difficulty in keeping it facing in one direction makes this almost useless.
I wonder what the minimum size at which a gyro-stabiliser becomes practical. But as Wikipedia doesn’t document the existence of an autopilot for full size helicopters the chance of getting one for a toy is small.
In summary, while I have had $30 of fun, I think that a more solid helicopter would be a better investment.
|
|
