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Member postings for Geoff Sleath

Here is a list of all the postings Geoff Sleath has made in our forums. Click on a thread name to jump to the thread.

Thread: Ageing lipos!
18/09/2019 11:17:52

If you still have some ic engines then they may work OK on an electric starter - saves lugging a heavy lead acid battery around. Or use in something less critical like a small rc car, perhaps?

Our bathroom radio is mains/battery but we use it with batteries. It's an ageing Roberts which should take 6 'D' cells, which would be costly, but I've modified it to take a 7 cell NiMH 3000 mAH pack. That pack has been in use for over 5 years but perhaps your old LiPos might be used in something like that.

Geoff

Thread: RCM&E 2019 Fly-In - pics etc,,
15/09/2019 23:46:59
Posted by Ray Watts on 15/09/2019 22:30:12:

Very good weekend at BMFA Buckminster this weekend so thanks to the RCM&E team.

Friday and Saturday had amazing weather and still got lots of flying in the dull conditions on Sunday.

The site was as immaculate as ever so a big thanks to the Buckminster crew and Manny.

I hope there is another event next year and that we can make it.

Good to make new friends.

Great shot of my EFXtra David 👍

Cheers

Ray Watts

It was certainly a great weekend and Avice and I enjoyed it (we even managed to get a bike ride out of it). Of course Ray's weekend was enhanced by the old couple camping next door Nice to meet you and Mandy, Ray.

btw the inadvertent s/c flash which I thought had damaged half my 308duo iCharger turns out to be merely the balance board and quite repairable. Not so sure about the LiPo - which suffered a dead short for about 1 sec - I'll check it tomorrow.

I even managed to bring home all the models I took and in the same number of components.

Geoff

Thread: What replacement for brushed
13/09/2019 00:13:53

I have a Gliderdrive motor in my Phoenix 2K. I think it's the 960kv version. It's very convenient and neat with the connections at the back removing the need to be careful how you run the wires to avoid the spinning case (which in these motors is contained in an outer shell anyway).

As Pat says, you can set the power output to whatever you need simply be choosing an appropriate prop. I think I've under-propped mine because I didn't need the extra power.

Geoff

Thread: Ashbourne 2019
12/09/2019 00:00:30
Posted by Tim Hooper on 11/09/2019 22:49:06:

Gimme my oatcake, dammit!

Tim

Oh blimey, you're not coming ... again, are you? cheeky

I suppose I'll see you there, then - oatcake and all.

Geoff

Thread: Motor pulsing
11/09/2019 22:19:23

The most likely culprit is a quirk of the esc design (or a fault in the esc. Motors are relatively simple and either work or have an obvious fault ( eg loose magnets, burnt out winding, faulty bearings) so would think yours is probably OK.

ESCs on the other hand are very sophisticated and need first to generate a signal to create a rotating magnetic field at a rotation proportional to the throttle input and then, via power semi-conductors feed high currents (the average smallish foamie like - say a Wot 4 - draws upwards of 40 amps at full throttle). Power means high current and with it higher temperatures, neither of which electronic circuits particularly enjoy. Then there's the BEC providing low voltage to the receiver and servos.

In view of that I'd try a different ESC before looking elsewhere. Make sure it has, at least the current carrying capacity as the one it replaces. As Simon mentions above, one step/substitution at a time is the reliable route to fault finding.

Geoff

Thread: Mark’s Peggy Sue 2 Build
10/09/2019 10:17:29
Posted by Peter Miller on 10/09/2019 08:18:37:

Hi Mark,

Like you I just love building. I have to have something on the boar.

I think that you will love Peggy Sue 2. She just asks to be thrown around the sky non stop. Mine only flies straight and level when inverted.

I know. But it's a bit of a pig when things don't go right cheeky

Geoff

Thread: IC or Electric for Ripmax DeHavilland Tiger Moth
09/09/2019 21:41:39

Personally I'd always go for electric power if only for the reliability, cleanliness and convenience but it's a totally personal choice.

Both my 58" ws DB Moths (Tiger and Gypsy/Cirrus) turn perfectly well on aileron alone with lots of aileron differential - probably twice as much up as down. I do feed in some rudder sometimes if I'm feeling clever but it's not necessary.

Geoff

Thread: Covering with Solarfilm
09/09/2019 21:11:46

Well, I'm gradually succeeding both with the Ultracote and the Solarfilm. In both cases I was using too high a temperature. I've been using a setting of 135 deg on my Prolux iron which works well for the HobbyKing film I've been using recently but that's too hot for both Ultracote and Solarfilm which both prefer 120 deg. The Ultracote can stand 150 deg if necessary for final shrinking but it's not normally necessary.

The Solarfilm adhesive is better now I've got past the first few inches but it was definitely degraded in parts. I've redone a few bits that were particularly awful and they look much better with few wrinkles.

I really should update the build blog on my Ryan ST (well more like a few comments on progress). It's actually getting near completion and not long before the test crash.

Thanks for the comments and advice.

Thread: Horus X10 transmitter voltage low warning level
09/09/2019 11:19:57

Thanks for that curve, Masher. It illustrates my 'falling off a cliff' analogy very well. It looks like my 7.1v is ultra safe and I may knock it back to 7.

I checked the state of charge on Saturday evening. It looked full and I mistakenly thought I'd recharged since I'd last flown. At least all it did was force me to abort the current flight and come home an hour earlier than I would have.

There's an option to calibrate the voltage measurement (I'm using Open TX) but I couldn't immediately see how it worked or how to do it and it was too late last night. It was reading a tad over 8v (8.18 IIRC) but it could be varied with the RH display control. Seemed odd but I'll look into it further today. I'd like to display the actual number rather than the hard to see bars but I'm not sure if that's an option.

Geoff

08/09/2019 22:44:47

I've just recharged it and it seemed quite quick - just about 2.5 hours. Never had the warning before but I'm only too aware that Lithium batteries (these are Lithium Ion 2S 2600 mAH so nominally 7.2v) can fall off a cliff at a certain point and I'd rather that not happen with a model in the air.

I think I'll stick to 7.1 for now.

Geoff

Thread: Sopwith Camel Electric Conversion
08/09/2019 21:53:10

Thanks, Cliff. Just a bit more info to store away. I've done a few electric conversions now and they've mostly been successful. I was flying the Gypsy Moth today and I love it. I just hope my 60" Sopwith Pup is as good. I'll be starting the build in just a few weeks once my Ryan ST is finished.

Geoff

Thread: Horus X10 transmitter voltage low warning level
08/09/2019 21:11:43

I was having an enjoyable flight with my DB Gypsy Moth this afternoon when I was forced to abort when the bossy young lady who lives in my Horus told me in no uncertain terms that the transmitter battery was low.

Of course I landed immediately and I never lost contact but I checked the level of the warning and it's currently (or perhaps voltagely) set to 7.1 volts. I'm not sure if that's what I set when I first got the transmitter or if it's the default.

What level do others have? When I checked the voltage reading on the transmitter itself it still had 2 bars (out of 4 IIRC).

Geoff

Thread: Covering with Solarfilm
07/09/2019 12:23:11

Foxfan, Max specialises in odd but strangely attractive models.

Thanks for the suggestions. I think, as Ken suggests, my Solarfilm (as opposed to 'tex, which is usually very easy to use) certainly seems to have lost its stickyness. It's a few years since I used any but I don't remember it's being so reluctant to stay in place before and this is an old but unwrapped sample.

I've ordered 5 metres of HK light grey film as a back stop and went out this morning to get some PVA (all I have is Aliphatic and I didn't want to use that. While I was in Wilko's I got another tub of their excellent lightweight filler. I've used more filler on this build because it's all sheeted in1.5mm balsa on formers and 3mm stringers - of course 90% of it ends up as dust so very little weight increase in practice.

So I'm going to coat the fuselage in slightly thinned PVA after an experiment on some scrap balsa.

The cowl is a vacuum formed clear plastic affair. I've cut it right back by skinning the fuselage further forward (I don't need access as I'm using a much different motor) so it's much shorter. I've found I can apply the Solarfilm without distorting it with heat because Solarfilm uses a low heat adhesive. Not covered it completely but I'll have a go.

Geoff

07/09/2019 00:30:57

I've found silver a difficult colour to use in the past. The film I'm trying to use is several years old (8/9?) so I'm wondering if the adhesive has deteriorated somehow. I haven't used 'proper' Solarfilm since I discovered the better (IMO) polyester? types which are much easier to use. I'm rubbish at covering, anyway.

Geoff

Thread: Charge amps query
06/09/2019 21:52:34

Lead acid batteries are normally charged at a constant voltage rather than a constant current (like NiMH or LiPos). If the charge voltage is set (around 13.5v for a nominally 12v battery) then the battery will draw current as required and will reduce to almost zero at full charge. The current will be limited by the battery's internal resistance, which is lower the bigger the battery

There are 2 reasons for a low charge current. First is that the battery is fully charged. The second is that its internal resistance is high because the battery is faulty (I'd use a rude word but I'd get moderated )

Some get batteries, eg Cyclons ,have a special charge regime but one of those is a constant voltage because they're designed as an emergency float. I used to use Cyclons for my bike lights in winter and charged them at work with a bench power supply I commandeered for the dark season.

In your case, assuming the battery is serviceable, it's probably fully charged - or near.

Geoff

Thread: Covering with Solarfilm
06/09/2019 21:41:18

I'm at the stage of covering fuselage of my Ryan ST. The wings and tailplane are yellow and I've covered them with HobbyKing film which is superb and very easy to do. The fuselage is supposed to aluminium and I'm trying to use some silver covering I had in stock and it's proving very difficult to get wrinkle free (the fuselage is basically a 1.5mm balsa shell so a bit flexible).

I have some silver Ultracote (I think it's a roll I got to cover some repairs to a H9 P47) and it's proving really difficult to do adecent job, I also have a brand new roll of Solarfilm silver which is a very close match. Neither of them seem to stick very well (and yes, I have removed the transparent film from the glue side) I haven't used Solarfiln for ages but it does seem to go on more easily than than the Utracote.

Would it be a good idea to paint the fuselage with PVA to act like Balsaloc? Should it be watered down? If so, how much?

I have my iron set to 135 deg for the HK film , going up to 150 deg if extra is needed. I'm using the same for the Ultracote but 100 to 120 deg for the Solarfilm.

A little guidance would be appreciated. I'm tempted to scrap my old stock film and buy a roll of HK grey but I'm impatient and would like this model in the air.

Geoff

Thread: Best/Safe practice or wiring electricmotor - ESC- On off switch - Reciever
05/09/2019 16:52:32

I have a motor enable/disable switch on my transmitter together with a voice warning about its setting. On most of my models I don't bother with a battery isolation plug as some here advocate because connecting the battery is as easy and safe as having a plug which IMO is just another connection and a source of both extra resistance (slight) and potential failure.

On the one model in which battery connection has to be through the propeller arc because of way I did the conversion from glow to electric (my 58" DB Gypsy Moth) I have a safety plug in the motor, rather than the battery feed. That's a 4mm plug and socket on just one of the the 3 motor connections. That has the advantage of being both a protection and also allows all the other radio functions to be checked safely.

Geoff

Thread: New Poll - sticky situations.....
03/09/2019 20:22:17

The first Cyano I came across was something called Eastman 910 (at least I assume it was Cyano) when it was used by the Instrument dept at RR to stick strain gauges on engine components under test on either rigs or actual engines. They used to fail as the test progressed so it wasn't perfect but it was probably the best available.

That was in the 1970s/80s. I don't know what they use now - I've been retired 2 years yes

Geoff

Thread: Stearman wing plans
02/09/2019 23:25:30

I fitted a gyro to the rudder on my GP Super Stearman because it was squirming all over the place on take off. I hadn't had a problem with it before and that cured it. Then I remembered I'd had the same problem with a Precedent Funfly. No-one at the club (even the aces) could get it to track properly. I replaced the wheels which were a sort of foam and the problem disappeared. I did the same with the Stearman and replaced the well worn wheels and all was well. I should mention both clubs I've flown at had hard runways.

I crashed my Stearman on the second flight because of an engine cut at a very awkward height by tip stalling. The fuselage wasn't too bad but the wings on one side were badly damaged. I'd had an engine cut on the maiden, too, but at height so I was able to save the airframe. The engine is a 30cc Mackay petrol and the eventually I pinned down the problem to a faulty ignition unit which I replaced with a HK one and not had a problem since.

I picked up an old one and used those wings after repair on my fuselage. So I have a spare fuselage and perhaps the damaged wings (I may have thrown them away in a garage clear-out). I bought the wood to scratch build new wings but never got round to it. I'm afraid it's a bit of a hangar queen because it's such a pain to assemble at the field, it's still on Mux 35Mhz, and I'm so used to taking a few LiPos to the field rather than a can of petrol etc.

img_0524.jpg

Still a lovely model, though.

Geoff

Thread: Incidence Meter/Gauge Measurement
01/09/2019 20:59:41
Posted by PatMc on 31/08/2019 22:19:54:

Just curious, what are people checking the incidence angle with respect to & what's the reason(s) for the checks ?

I can see that this meter could be useful to check that wings plugged in to a fuselage are at the same angle but that can easily be checked during &/or after build by other methods. Other than that I'm struggling to think of any justification for this gadget.

I have a Robart gauge and use it regularly though not frequently. It's particularly useful with biplanes where the top wing incidence isn't fixed by the fuselage (which, in a decent kit, can be set accurately) but by a cabane structure which often has quite a vague position. I just like to be sure the set up is somewhere near what I expect so I have fewer potential problems on the test flight. You can also check that the wing incidences at root and tip are the same - or at least washed out rather than in.

They 're also useful for setting engine/motor side and down-thrust.

I last used the Robart device for checking the wing incidence relative to the tail-plane on the Ryan ST I'm building from the Easy Built kit (which is more like scratch building). I just wanted to be sure things were where they seem reasonable to be - the wing is 1 degree +ve

A lot of my professional life involved measurement so I suppose it's what I'm used to and aeromodelling is something I took up late in life.

Geoff

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