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Member postings for John Cole

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

Thread: Lipo battery instead of NiMH
05/12/2012 16:15:36

Why do LiPo & LiFe chaps think these are better than low self-discharge NiMH?

05/12/2012 12:13:13

I use a low-discharge NiMH from VapexTech . Look about halfway down the page for a flat 8-cell 2500 mAH pack with Futaba plug. £12.50 delivered. I charge AFTER flying and rarely need to top-up before flying. Charge with your normal wall-charger. Takes a long time the first time but thereafter you only put back what you take out (plus a bit). Easy to live with.

Thread: Computer - Typing problem
05/12/2012 09:12:59

Yes, in Chrome the Focus text-entry area has a yellow line round it, and that disappears if the Focus moves to another application - or indeed if you click anywhere outside the box. If you hit Tab then the focus moves to the next clickable field. In this case, it moves first to the Send button and then to the T&C link.

It may be that you, or a toolbar, have set up a hot-key ccombination other than the ones I've mentioned and that by hitting this combo you are switching focus.

The suggestion that you run an anti malware program is a good one.   MalwareBytes is reckoned good; I use IOBytes Malware Fighter.  Both have free versions.  I would also de-install any toolbars.  Click the symbol at top-right Customise / Control - looks like 3 bars one atop the other.  Then Tools / Extensions and clear any checked boxes.  Tools / Task Manager shows what's running as part of Chrome.

Edited By John Cole on 05/12/2012 09:23:38

04/12/2012 16:57:48

I'm not sure which browser you are using, but my explanation fits both Internet Explorer and Google Chrome. But it's easier to see exactly what's happening if you open Internet Explorer and then make sure the Menu bar is visible at the top. This is the one saying

"File Edit View Favorites Tools Help". If that is NOT visible then right-click in the empty grey space to the right of the "title" tab, and select Menu bar.

If you then try typing something (in a place that expects you to type, such as a search box) then the Insertion cursor will be immediately to the right of the last character you typed.

But if you now hit the Alt key, you will see that the Insertion cursor disappears, the word File in the Menu bar becomes highlighted, and the F is underlined. This reflects a basic characteristic of Windows: hitting the Alt key invites a hot-key Command - in this case F for File. Hitting Alt again, or Esc, or left-clicking where you are typing all cancel the effect.

You will see a similar effect in other programs. In Word you get a similar effect except that the Insertion cursor does not disapper - it just stops blinking.

Edited By John Cole on 04/12/2012 16:58:32

Thread: NiMH capacity
04/12/2012 15:11:04

Olly means the thin red wire connected to the centre pin of the plug going into your Rx. Throttle channel Not the big fat one going to the LiPo, though that would also force the Rx to use the battery!

Thread: Computer - Typing problem
04/12/2012 15:07:30

I think I may have the answer. If you are typing in this box and accidentally hit the Alt key (between the Windows key and the spacebar on a full-sized keyboard) then the "insertion" cursor disappears. Click in the box to restore it. Or just hit Alt again. Does not happen with the Alt-Gr to the right of the keyboard.

Thread: Multiplugs for several servos.....
28/11/2012 16:46:38

The individual + and - pins on a Rx are connected to 2 common lines inside the case. So there's nothing wrong in principle with using common lines. But because all the power for all the servos goes through them you are more at risk from a poor joint / connection in them than you are if you use individual feeds.

My guess is that this is what happened with your plane: marginal connections were OK to start with but then got worse (through use / bending / wear) and caused this problem.

Thread: home built fuel tank
28/11/2012 16:38:18

Ernie: can you take a photo of the tank bay and post it here? Then we can all see what the problem is. Don't be shy...

Thread: Multiplugs for several servos.....
28/11/2012 14:42:15
Posted by Olly P on 28/11/2012 12:53:54:

Hmm..Think I'll try a 9 way plug for the TB3 - 5 signal wires, (2xthrottle, 1x Aileron, 1x Parasite Release......

Isn't there something in the BMFA rules about not releasing parasites from model planes?

Thread: home built fuel tank
28/11/2012 14:38:51

Engine Doctor: rust is oxidised iron. Brass and copper CANNOT therefore rust as they do not contain iron. Tinplate is mild steel (i.e. an iron / iron carbide mix) coated with tin. The tin stops the rust from forming. NItromethane is NOT acidic and will attack none of these metals. The products of its combustion are acidic, but the material itself is not. See for instance this.

But I agree with your conclusions: modify the model.

Thread: Close up photos and the use of Macro?
28/11/2012 12:51:12

1. The glowplug is not in sharp focus. If you are using Macro mode then get to within 25 cm of it and choose Aperture priority and set it to F8.

2. I think the last one shows it off best. What's wrong with a shadow?

3. I copied that and made a few changes using a simple photo editor.



Edited By John Cole on 28/11/2012 12:53:50

Thread: home built fuel tank
27/11/2012 11:07:08

Tinplate is pretty light and solders relatively easily. Your alternative sounds horrendous to me!

But why can't you use a conventional tank?

Thread: Close up photos and the use of Macro?
27/11/2012 11:02:58

You have a really nice "bridge" camera with very powerful zoom. I think kc's comment applies more to "normal" cameras. Your camera supports Canon slave light / flash units.

You need to use Macro if you need to get in close to fill the frame. You need to switch Macro on if you are nearer than 50 cm to the subject, in wide-angle mode. If you are too far away then you will not get the focus-lock icon. And Yes you should use a tripod and also you should user Timer mode so your shot is not blurred by pressing the button.

If you want both the near and far bit of the subject in focus then you need to set a narrow aperture and the camera will compensate by setting a slow exposure. Max is F8.

The editing capability of the supplied software is pretty basic. I recommend you get something more capable and spend time really learning how to use it. I use several programs; Photoshop Elements is good but a bit pricey. Paint.Net is free, and is quite useful if very slow. Once you really know how to use the software then you will find you can compensate for many of the issues raised by other people above, e.g. by colour-cast management and gamma compensation.

Edited By John Cole on 27/11/2012 11:03:50

Thread: prop rotation
27/11/2012 09:50:05

Eric: just look in the box and examine the spinners: I think you will find that they are both cut for 2-bladed normal-rotation props. And 11*8*3 would much over-prop the motors.

26/11/2012 16:52:21

If this is the model you mean then here is the assembly manual.

It recommends 2 2-blade 9*6 props. A number of the illustrations clearly show 2 same-handed props (and the 2 spinners look identical), so not using a reverse-pitch prop for counter-rotation on one side.

Thread: 12v gel battery charging questions
23/11/2012 20:00:31
Posted by Simon Chambers on 21/11/2012 20:36:28:
3. It'll charge up to around 14 to 15v like a car battery. Don't need to worry about the exact voltage, however make sure you select the correct battery nominal voltage on your charger - which is probably 12v.
4. Don't worry about the cut off, infact for charging the Lead Acid keep it well above (i.e. 10000mAh) - otherwise it may say it's finished before it really it is.

Don't worry about the cut-off voltage or current? I disagree.

And so does the manufacturer of the SLA charger I linked to.

Thread: Vettel or Alonso for the championship?
23/11/2012 18:15:24
Posted by kc on 23/11/2012 18:03:26:

But motor racing is so unpredictable that anything can happen!

OK so you want to put money on HRT finishing 1 and 2?

Thread: Mcafee AV problem
23/11/2012 18:09:22

Even if your licence has expired the scan should work: you just don't get virus updates.

I would run another one-time scan: HouseCall from Trend Micro and make sure you do a complete scan not the default Quick scan.

Then de-install NAV and install any of the free AV programs. I like AVG Free 2013 as I find the LinkScanner function helpful in avoiding bad sites.  Make sure you don't pick the free trial of the paid-for version and also I suggest you decline any of the add-ons.  Any of the free programs will be better than an out-of-date NAV!

Edited By John Cole on 23/11/2012 18:13:14

Thread: 12v gel battery charging questions
23/11/2012 12:41:24

If it's a sealed gel lead-acid battery (SLA) then I think Simon's advice is incorrect. You MUST use a charger that cuts off at the correct voltage. Unsealed car batteries can safely be charged above their full-charge voltage as the electrolyte then breaks down releasing oxygen and hydrogen (which is why car battery chargers say you must use them in a well-ventilated space as this mixture is very explosive). If you do this with a SEALED battery ...

Special chargers for sealed gel batteres cost just a few pounds and cut off at a safe voltage.

On-line checks suggest a fully charged SLA battery will read 13.65 volts and this will drop when taken off charge to 13.2 volts after several hours.  This link suggests fast-charge to a target of 14.45 volts with a drop to constant-voltage charge at 13.65 volts. The charger referred to is for a very small SLA: 1.2 AH. so the peak charge current is just 300 mA.  Yours is 6 times bigger and that suggests a peak charge rate of 1.8 A / 1800 mA.

Edited By John Cole on 23/11/2012 12:51:12

Thread: Selecting a Ubec
23/11/2012 12:24:16

Your bare airframe + u/c weighs 1150g. I have just weighed a 30-equiv motor, prop, ESC, plugs, Rx and they come to about 270 g. Add a 2200 3S LiPo at 200g and some servos (maybe 80 g if you have 2 * 9g and an old heavy one. No rudder?) My add-ons come to 550g. So your t/o weight is going to be about 1700g (3.75 lbs). Allowing 220 w/kg or 100 w/lb indicates you should have about 375 watts, or draw about 34 amps from a 3S. This would give you about 8 minutes flight on 50% power.

Edited By John Cole on 23/11/2012 12:26:46

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