Rob Cope

This year, trying out FPV in a small way - but without vertical-axis propellers Hubsan Spy Hawk so far   Edited By Rob Cope on 27/04/2014 11:48:11

Hi,   How many other 35MHz dinosaurs are there out there? Just bought a backup 35MHz 6-channel Futaba transmitter at bring-and-buy - in case of tragedy...  I am currently investigatng corona synthesized receivers.   Regards, Rob Edited By Rob Cope on 25/04/2014 12:51:57 Edited By Rob Cope on 25/04/2014 12:52:21

Tied down everything I _don't_ want to get rid of... ...near Southampton; fairly windy all day, but midnight-six are the critical hours here... Edited By Rob Cope on 27/10/2013 20:02:41

Thumbs man. Tried fingers and thumbs - great on flight sim where the TX can be held horizontal, but useless for vertical transmitter on site (35MHz) so thumbs it must be unless I want carpel tunnel syndrome, spondilitis, RSI, etc...  P.S. Mode 2; no tray; no beckstrap; Futaba/JR Edited By Rob Cope on 09/04/2012 20:42:10 Edited By Rob Cope on 09/04/2012 20:46:23 Edited By Rob Cope on 09/04/2012 20:46:48

High Street Shop: Best parts stock, advice and service to those who go in with a positive attitude = Mainly Planes & Trains, Chandlers FordEdited By Rob Cope on 16/12/2009 22:01:04

Two things... Most of (if not all of) the ARTF damage at our club has been from bad luck with conditions or plain mistakes.  This equally applies to all planes, not just ARTF.  However, following the discussions on undercarriage, I think ARTFs might have a higher survival rate if some of those plain-cut-ends were tapers.  This is especially true in undercarrienge mounting where the shock-loads should be dispersed across the fuselage/wing rather than concentrated into a point where the undercarriage bracing abrutply ends. ...agree about the Irvine Tutor 40 covering - going brittle after 18 months - also have you tried to repair it? Melts and browns at the touch of a low heat iron!  Be very wary, _very_ wary...

Hi David, Sorry to get to you so late.  I've heard there's a sliding diagonal arrangement using a splitpin/hinge or the like.  I think there's a note in a previous scale article.  It seems to be this one.  http://www.modelflying.co.uk/forums/postings.asp?th=10970  The biggest problem is the extreme forces needed for short acting control actuators.  The best way I can see to achieve this is to make a metal beam with two uneven length 90 degree bell-cranks, one at each end.  The very short acting arms are linked by tight joints and a very slopless link.  The bell-cranks would be mounted at 90 degrees to each other - end 1 with the axis along the wing - end 2 with the axis vertical.  It could all be built on a piece of ally angle with the joining link running allong the outside of the V corner.  End 1 is mounted at the hinge line with the long arm firmly fixed into the control surface using two wires (one near one far) to spread the load into the surface.  The beam is glued/screwed to a doubler along a wing rib - with suitable bracing.  End 2 has a short arm to drive end 1 and the long arm for servo power.  End 2 translates servo power from pushrods along the wing, like an ordinary bell-crank, into fore/aft high power short action.  The 90 degree twist in the joint between end 2 and end 1 allows end 1 to drive the control surface up and down.   Now all we need is for a manufacturer to start building various scales of these devices and few scale modellers would use anything else!  You can tell I haven't actually built one of these...  It is theory, but should work because all the high forces involved are retained within the metal structure of the device.  Regards, Rob Edited By Rob Cope on 15/09/2009 21:54:55 Edited By Rob Cope on 15/09/2009 22:08:44 Edited By Rob Cope on 15/09/2009 22:10:41

Hi,   Not that I'm a scale builder yet, but it seems we have:   Stand off and squint (not scale at all) Sport scale (design compromises) Stand off scale (colour, outline good) Semi-scale (very close to right shape, colour & patterns, some significant detail) Scale (right shape, colour, patterns, much detail - door handles, etc) F4C (bookworm detail)   Is that a good list to start with? ...and in the right order?   Regards, Rob Edited By Rob Cope on 15/05/2009 21:04:08 Edited By Rob Cope on 15/05/2009 21:04:45

Well, I believe there's a 4-engine Elec/Glow warbird coming up in the autumn, so that wouldn't be a good choice.  So,   o   Scottish Aviation Twin Pioneer      It has such an amazing appearance      5 channels?   o   PBY Catalina, Glow, with retracts and retracting tip floats - 70"+      Classic      6/7 channels?   o   Howard Aero 500 Super Ventura        Sleek looks      4/5 channels    

Centre of gravity should be near centre of lift. Centre of lift as I have it is: 1/3 span (from centre-line) and 1/3 chord (from front) So, your COG should be near there, but as others have said, please, please, from bitter experience, head for COG 1/4 chord rather than 1/3 chord as a nose-heavy plane is user-friendly whereas a tail-heavy plane is a "nightmare on steroids". It just keeps "rolling off the top" - like a plane flying too slowly - it just can't keep stable. Regards, Rob

Terrence, Your "picture" prolly doesn't encourage contact from female modellers. Where is your group located geographically? It's OK us southerners agreeing to meet up, but if it's in the dales, that's a whole lot more difficult than Bristol, etc. No offence to Londoners, but their city is dirty, cramped and still full of traffic!!!!! Regards, Rob

If only...

North west of portsmouth... We start flying at 10:00 and at 9:00 all was well so a few of us headed down.  A couple of us managed to get in the air in time but as one was flying, the blustery day sprang up out of nowhere and he had a bumpy landing.  No-one else dared.  Then the rain came in dribs and drabs and we all went home.  Forecast for tomorrow is heavy rain followed by showers

Least, but not last

Wow! Peter, Now electric starts to make sense.  I've heard of kv which should be k/v and is often quoted as rpm/v but I now understand how that can actually be applied to a model. Thanks a million... my days of IC-only may well be numbered... Regards, Rob

Thanks Brian, I've used capactiors loads, but inductors have always been a bit... well... scary... all those volts on disconnecting and rarity of experience. Regards, Rob 

Hi Peter, Impedance = resistance plus reactance 1 / impedance = admittance; 1 / resistance = conductance; 1 / reactance = susceptance However, the bottom equation does not seem right to me. Here's my reasoning. If we do the algebra starting at the well known equation, and substitute the reciprocal names above, we get Impedance = resistance + reactance 1 / admittance = 1 / conductance + 1 / susceptance multiplying by admittance and dividing by (1 / conductance + 1 / susceptance), [so long as it's not zero] we get admittance = 1 / (1 / conductance + 1 / susceptance)) multiplying top and bottom on the right by (conductance x susceptance), [so long as that's not zero] we get admittance = (conductance x susceptance) / (conductance + susceptance) This is the product over sum form that is also applied to parallel resistors and series capacitors (and I suspect series inductors.) Regards, Rob

Hi Peter, (-:   Would you be able to set up your profile to accept private message please?   Regards, Rob

Hi, For my remote glow connector, I cut a slice of cereal packet as an insulating washer. This insulated the bent wire clip nicely. Don't go too big or you could affect cooling of the head. My remote connector had a fake glow plug top to connect to, so no change of connectors, just clip the usual glow stick on and go. It's not required now as I side-mounted the 2s rather than the completely unreliable inverted 2s installation the 2nd hand plane came with. Now all I need is room for a larger fuel tank!... Regards, Rob

Hi again, Don't you just love the fact that speaker cables must not only be oxygen-free, but fitted in the drawn direction from amplifier to speakers... Now I am a cynnic, but the ignorance of the fact that it makes no difference anyway is exceeded in absurdity by the ignorance of the fact that the conductors not only carry the current in different directions (one in, one out) but that it's an alternating current travelling to the speakers anyway. Supply DC to them and they fry! Regards, Rob

No chagrin... It's an easy slip to make. Done it lots myself in the (recent) past until someone put me right. Power is a tricky subject - especially in audio with decibels when it gets even more confusing... Conservation of enery (or power) is always a good check. Half power in... so somehow I must get half power out! No criticism implied even though reading back, my post "sounds" a little abrupt. Regards, Rob

Hi All, Sorry to butt in PDR. I think that would lead to a perpetual motion machine... in reductuo ad absurdum... The motor will not run at 71% power... The effective voltage supplied is reduced to 71% of the full power value. However, the current drawn by the motor is reduced in the same way.. Thus the POWER is reduced to 71% of 71% (voltage times current) which is, of course a half. Regards, Rob

Hi All, No experience here, but perhaps a tensioner spring pulling the line out of straight between two hard points would be good - similar to a car engine cam chain tensioner sprocket. Then you can provide various anchor points and use the appropriate one rather than having to tie off the line at exactly the right length on the spring. Maybe even tie the far end of the spring - but with far better tension control owing to the angles.  Pulleys or beeswax may be needed to provide for smooth running.  Any good? Regards, Rob

Hi, Nothing! Cut some formers for the Nexus Halifax... Then Tony offers a faithfully scale Halibag plan... I'm in a holding pattern still... We'll see. I've not built from plans before so perhaps I'm taking on too much. Somehow I feel I ought to get on with the Nexus model... as a run-up to Tony's masterpiece when it arrives! Lots of expense in engines if I can't reuse them though - even if they're SC. Has Tony any info on what engine sizes he's thinking of? Regards, Rob

Hi Richard, Hobby Store (RCM&E) has a 533mm Concorde (RC1335) which would scale nicely 2:1 up to make a 3'6" span.  That might be suitable? Regards, Rob