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Martin Harris - Moderator

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Everything posted by Martin Harris - Moderator

  1. A time switch that you can set to go off after an appropriate charge time after flying and then switch on for an hour a day will keep a  battery nicely topped up connected to a normal trickle charger.  Simple peg type ones are certainly capable of this.
  2. Frank's quite correct in all he's stated.  You must set them UP from the trailing edge.   It doesn't look like the Goldberg version.  Maybe someone will recognise it? Nice looking model, though.   I'd already tried that procedure to see the pictures but it doesn't work (for me, anyway).
  3. To be honest, I'm not sure how to identify your album.   Strip ailerons run almost the entire length of the trailing edge. " Scale" ones would typically be between 1/3  and 1/2 of the wingspan starting near the wingtips.   Washout is where the wing is deliberately warped to decrease the angle of attack at towards the wingtips to allow the inner part of the wings to stall before the tips which reduces the chances of a wing suddenly dropping at the stall (tip stalling).   If you have scale ailerons, setting them both up (perhaps 1/8 of an inch) from being level with the trailing edge changes the effective aerofoil section to reduce the angle of attack, thereby giving a similar effect to washout.
  4. Obviously depends on the design of the model - mine (Goldberg) is a pussycat.   Does it have scale or strip ailerons?  If they are scale (outboard) you could set them up a few degrees to introduce some (extra?) washout until you can evaluate its characteristics.
  5. Failing bearings can produce small particles of metal that can circulate through the engine and damage plugs.  Did they blow after starting the engine?   Have you changed fuel recently?  Perhaps there's a rogue element in some new fuel?
  6. Spare me from the Electric Evangelists!  Why do "electric only" fliers feel the need to preach at us oily enthusiasts at every opportunity - are they trying to convince themselves?   Electrics have their place and are commendably quiet, clean and powerful (if expensive at the top end).  I have some and enjoy them immensely.   ...BUT where's the soul?    
  7. Are you using a power panel?  Some of them are prone to going faulty and delivering the full 12V from the flight box battery to the plug...
  8. Removed this as I think, on reflection, it may not have been entirely relevant.
  9. Yes, I'm sure they would.  I was taxying over some patches of grass yesterday quite successfully.
  10. Pretty much a perfect flying day.  Our field is still covered in snow and some of us used skis, others used hand launched models and one or two got off from a small cleared runway. 
  11. Surprisingly (for the most part) the skis rode over the footprints (bomb craters) very well.  Luckily, most were aligned across the runway rather than along it.   Looks like we'll be back on wheels in the near future, though...
  12. http://i572.photobucket.com/albums/ss163/scimart/2009_0214oct080007.jpg   SKI SATURDAY
  13. In answer to the question, yes and it was a brilliant day.  Pleasantly warm, negligable wind and still enough snow left to keep skis employed on a growing number of models!
  14. Another thing is to make sure (if you use a transmitter tray) that the range check button wasn't accidentally operated when it was put in it (depends on the radio, of course, whether this can happen)
  15. In my opinion NOW is the time to make your skis before the delights of spring drive the thoughts of snow out of your mind - only to re-surface next winter when the snow lies deep and crisp and even and you're rushing around looking for bits of ply to lash something up.   Who knows, in a week or two you could even be congratulating yourself on your foresight!
  16. Is anyone going radio control model flying this weekend?   What a silly question!   Dahn Sarf we don't let 7 inches of snow stop us so this weekend should be a doddle...'er indoors willing of course.
  17. "I don't see the problem with what it is called Martin."   Neither do I but it seems to be a major problem to some of the thread contributors!   I don't know how accurate it was, but it was once an often quoted  "well known fact" that according to aerodynamic principles, a bumble bee was incapable of flight.  A perfect example of your last point!
  18.  Quote: "I know the term 'semi-symmetric' is locked in modelling yore, but it is a nonsense term, something is either symmetric, or it ain't, and if accurate exchange of information is the goal, then we shouldn't use nonsense terms, specially with single interest subjects." Perhaps we should rename semi-symmetric as nearly-symmetric?
  19. Odd - you seem to be well past it!    (says 130 on your ID - or have you been very busy since 13.41?)
  20. Kevin,   You're a lucky so and so to have such an interesting lump to play with!   Why don't you download the OS manual for their 5 cylinder radial   http://manuals.hobbico.com/osm/fr5-300-manual.pdf   ...which I suspect will be very similar?  Page 15 seems relevant...the nipple is a drain plug and should be in place for running.   I suspect (never having been lucky enough to own anything like this) that the idle mixture may be grossly rich, giving a slow transition.  Probably not helped by the volume of the common induction chamber that I suspect your engine uses?
  21.   Hi. I have a FS400AR SC radial in my ¼ scale Stearman. The instructions that come with the engine leave a lot to the imagination (literally) it has an on board glow system powered by a 13000mah NiMh which dose the job very well. My problem is that I still can not get it to run smoothly. The idle is reasonable but takes 2-3 seconds to pick up when the throttle is opened. The top end is lumpy. The needle is open 1 turn and if I open it any more it runs too rich and if I close it any more it runs to lean and dies. When I say open / close Im talking 1/8 turn. There is also a breather nipple on the bottom of the engine. By all accounts following standard 4 stroke logic this should be open. If I leave it open it turns into a leak and fuel /oil goes every ware, the engine will not start. If I close the nipple the engine starts perfectly and runs as above but oil leaks from the push rod covers. When I open the nipple after a run I get an abnormal amount of oil from the crank case. The fuel I am using is 10%nitro, 18%oil the rest methanol. Any one had the same problem or any suggestions. Regards Kevin.
  22. As an ocassional flirter with the dark side I'm not really qualified to comment but I've had reasonable results and some of my more electrified friends swear by it.
  23. It's the sound that gets me - if you listen to the video carefully you can hear the skis slithering across the snow - even better in real life.  Acceleration to take off can be done in an instant as there's virtually no resistance from the ground but it's far more fun to let it run on the skis for as long as possible.   As I said in my last post, I've ignored the advice from the link re. my articulating mechanism but it is a very elegant solution which I may well adopt in the future.  The articulating skis worked even better than last Saturdays experiment with fixed skis - the sliding turns on the ground, for example, wouldn't have worked. Even though the skis are fairly short, they rode over footprints etc. very well.
  24. Timbo,   Thought you might like to see what the "Southern Softies" were up to in the snow today...never go out when it's below 10 C indeed !!!   http://s572.photobucket.com/albums/ss163/scimart/?action=view&current=VIDEO_018.flv    I'd like to point out that it wasn't me flying in the clip - I'd handed the Limbo Dancer to one of my mates for this one.   ...and sorry about the film quality - it was taken on a mobile phone (don't tell the committee I took it onto the flightline!) and it was snowing quite heavily.   Despite the advice on the link in the post above, I found the modification since the picture of the skis involving rubber bands and restraining links to allow the skis to float worked extremely well on the icy snow (compacted/melted from @7 inches on Saturday to @3 inches today. )   Brilliant fun and well worth the effort of making the skis - I can only recommend making some even if you're not expecting any more snow as you'll have them for the next time!
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