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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: home built fuel tank
20/12/2012 11:31:24

Your friend's point about methoxide corrosion: aluminium is particularly susceptible to methoxide corrosion for 2 reasons: aluminium is easily oxidised and the surface of metallic aluminum oxidises rapidly in miost environments. The methoxide corrosion depends on an oxide coating. Once the oxide has corroded away it will reform and then be attacked again by the methanol. Additionally, the methoxide formed is umstable in the presence of traces of water, and converts back to yield a hydroxide ion. This attackes aluminium in a different way, forming aluminates and hydrogen.

Tin does not have an oxide coating and so is not attacked this way. Neither does copper.

Thread: Unresponsive elevator but lucky escape
18/12/2012 14:48:02

A: your Tx is partly broken

B: your Rx is partly broken

C: that servo is broken

D: you set D/R "on" to give zero movement, and switched D/R on in flight

E: you are mistaken, and the elevator was working

If I think of any more possibilities ...

Thread: 6J setup advice
18/12/2012 14:42:07

I've has a quick look at the manual and as I read it all 3 controls are switched together, by the one switch you select. Bit like my 6EX.

Thread: Futaba Servo plugs
18/12/2012 12:15:10

Solder half of an extension lead to the board? This copes with the polarity tag issue and ensures correct-way-round connection.

Or try this when it comes back into stock.

Or just standard 0.1" header strips (bottom of that page).

And I've found 2.5 mm also works - a standard JST size.


Edited By John Cole on 18/12/2012 12:35:15

Thread: What do you take to the field.
17/12/2012 17:32:22
Posted by Erfolg on 16/12/2012 15:24:33:

I have wondered at the practicality of charging at the field with the advent of Lipos.

The first issue being that most seem to use for field use, at least 3s, which is pretty close to 12v nominal voltage of the car battery.

Not an issue: chargers with12v input "pump up" the voltage to charge multi-series LiPos.

Having said that, I agree about what to do. Field charging made more sense when LiPos were expensive. I only charge at home now.

Thread: failing Nmih
17/12/2012 16:25:01

I charge AFTER flying and ony bother to check the night before I go if it's more than a couple of weeks since I last flew (I use LSD cells, see above). I only then bother to re-charge if it's significantly below 11.0 volts.

Minimum safe? Totally academic as far as I'm concerned. But this is what it says in the Futaba manual. The Low Voltage Alarm sounds at 8.5 volts.

9.4 Volts – No more flying until recharge.
8.9 Volts – Land as soon as safely possible.
8.5 Volts – Emergency – Land immediately!
17/12/2012 16:13:29

Fully charged, I see 11.3 or 11.4 volts on my Futaba - on load.

Thread: Watch out there's a scammer about
17/12/2012 10:24:04

This puzzled me. I use Ebay and PayPal a fair bit. I could not see how the scam would work. I still don't really understand. But I contacted PayPal and they explained how Payment Protection works: PP ONLY applies to items you can and do post, and you must use a service with proof of posting. If you let people collect then PP does not apply. I didn't know that.

So my guess is that they take your money and then tell PP that you never delivered, asnd get the goods AND their money back.

There's an apparently unrelated thread about HobbyKing charges, and the OP-er incurred extra costs on his Debit Card. He would not have had to pay them if he had used PP. He didn't use PP because he had been scammed like this.  He sold and delivered a drum kit after being paid through PP. But PP took the money back as he had delivered, and I guess he had no proof of this..

I would say that cash on collection sounds better than PP in this case, but if not then a written bill of sale where the buyer SIGNS on collection ought to satisfy PP. But in the case of THIS thread the collector would not be the buyer.....

Edited By John Cole on 17/12/2012 10:25:46

Thread: Selling on Ebay - Photos
15/12/2012 16:50:57

Here's an example of a Jaguar I sold for a friend.  It shows both methods: the description includes quite a few photos but also a clickable link to the full album.  Not sure how long it will remain visible to you.

Edited By John Cole on 15/12/2012 16:52:50

Thread: The best OSD with RTH
15/12/2012 15:15:30

Spot on!

Thread: What determines a planes speed?
15/12/2012 15:12:17

Power, drag, thrust at speed (i.e. appropriate prop pitch), strength, inherent stability, flutter-free control surfaces (and flying surfaces!). Weight has only a very small effect in straight and level flight.

Oh, and pilot skill if you want it to fly twice.

Thread: Selling on Ebay - Photos
15/12/2012 15:06:41

The standard for Ebay is ONE smallish photo free, and if you want better than this you pay. I feel that lots of large sharp photos are the best way of selling on Ebay - a good photo is certainly "worth a thousand words."

If you delve deep into the Ebay help screens you find that you can do it for nothing. Here's how. This explanation is a bit brief. If you want complete simple step-by-step details them PM me with your Email address.

There are two separate ways you can do this, and you can use either just one or both in one listing. Embed photos in the description and/or put a clickable link to a photo or an album in the description. Both rely on your uploading your pix to a hosting srvice first. Make sure you use one that's Ebay-friendly. IS. Photobucket IS NOT: they cut links to Ebay lisitings automatically.

If you just want to put a couple of pix in then see the next step. If you want to link to a lot then use a clickable link to an album. So create your album in Flickr and exit to Your Photostream, right-click on it and pick up the URL: Copy Link Address. Then go to your Description, switch to HTML View and insert the link address using the following syntax:

<a href=""> Click Here for Ebay</a>

Put it in following a block marker that says </DIV>

The bit in quotes is the link address. Put your link address in there, within the quotes. The bit between > and < (in this case Click Here for Ebay) is the wording that will appear where you want the viewer to click. Note the link doesn't actually become clickable until you have posted the listing. Practise first in their Sandbox category:

Everything Else>Test Auctions>eBay UK Tests - DO NOT BID

Ebay restrict what you can link to from your Description, but it's fine to link to extra pix.

To put pix directly into your description you again collect the URL: click on a photo in Your Photostream and then use the Share menu above it. You want the HTML/BBCode, selecting HTML. Copy this and paste it into Notepad, and trim off the start and end so it looks like

<img src=""

Depending on which view you have copied from, it may end _b or something else. Change it to _b for BIG!

Now the magic bit. That link will bring it in FULL SIZE, and to just make it screen size all you do is to insert a "." changing

staticflicr to

Then all you do is to copy this string from notepad and paste it into the HTML view of your description. Put it in after a block marker that says </DIV> Switch back to normal view and the picture is there in all its glorious large-sized detail. Do this for each of your pix.


Thread: The best OSD with RTH
15/12/2012 13:48:31
Posted by Biggles' Elder Brother - Moderator on 15/12/2012 12:30:43:

I'd post in this thread - if I had the slightest idea what the title was about crook


I'm not sure that's really enough! But it seems many contributors to most threads see it that way.

Thread: MVVS Diesels
15/12/2012 13:24:29

I would try using an over-diameter prop initially. It's (back) firing OK at high compression so maybe the extra inertia of a bigger prop will carry it through firing / TDC. You could also try reverse-flicking it.

Thread: failing Nmih
15/12/2012 13:19:17

When you charge a battery after use, all you do is replace what you take out, plus a factor for the charge/discharge inefficiency. The capacity is totally irrelevant.

My Futaba Tx draws 250 mA and my charger supplies 70 mA constant current. I nowadays fly only electric so flying time = Tx-on time. For a typical example: 3 flights of 15-20 minutes = 1 hour Tx on-time. So it recharges in 4 hours to 11.3 V on the Tx display ( 4 * 70 = 280, which allows for the inefficiency).

Or, as it's a low-constant-current charger I can safely leave it on all night.

What could be simpler, cheaper or safer?

15/12/2012 12:00:21

I was referring to what WeyFly had done as complicated.

WeyFly: buy a LiPo pack and fit a charging plug. In parallel fit an output lead including 2 in-line sillicon diodes. Terminate with a Tx plug. Test to establish in-use voltages and correct operation (and no overheating or blowing of the output stage), test the reliability of the Tx low-voltage alarm and the remaining useful safe period of use after this sounds. Remove LiPo from Tx every time for charging and re-fit (or risk the Tx if the LiPo catches fiire if overcharged - no overcharge-prevention circuitry fitted as you would find in e.g. a laptop battery/power pack).

Me: buy NiMH pack pre-fitted with Tx plug and put in Tx. Charge after use with normal Futaba wall charger, and only recharge before use after a long gap between sessions (sevral weeks).

Can't charge a low-self-discharge pack with a wall charger? Rubbish.

15/12/2012 11:23:41

Pretty much the same as I get with an Instant low-self-discharge NiMH pack from VAPEXTECH (the green ones, not the red). £12.50 delivered, with a Futaba plug on, and no worries about how to charge: in the Tx using the Futaba wall charger. Why make it complicated?

Edited By John Cole on 15/12/2012 11:25:48

Thread: Computer - Typing problem
15/12/2012 11:09:36

Your immediate problem appears to be a badly-written application which is grabbing focus but NOT showing itself as the main foreground window. "Focus" is the application program (plus data entry field) that the PC links to keyboard input. An application running in background can reasonably grab focus if something goes wrong - as it urgently needs to tell you something, or ask you to do something. But if it doesn't at the same time make its window pop to the front then you can't see what it's asking / telling you. So your application is at fault.

The situation which has triggered it could be a software issue or hardware. There's no way of knowing until you find out what the application is and why it's grabbing focus. There are 3 things you can try:

1. Change things that your gut tells you might be wrong. That's the advice you are getting from some people, and seems to be what you are doing. If you guess right, this works. The problem is that there's a lot going on inside your PC, most of which you don't know about. I have just checked mine and I have 44 Processes running. Each one has between 1 and 70 threads running: say 1000 threads in total. Explorer (what controls the screen) has 221 User Objects running. There are 46 Local Services running. So there's a lot to choose between.

2. Assume it's not a Microsoft problem - generally a good assumption but not foolproof. Then run MSCONFIG and choose Services. Select non-Microsoft. I have 6 non-Microsoft services running, and 11 loaded but stopped. Microsoft would advise you to try stopping ALL non-Microsoft services making a note of which ones you've stopped and see if that stops the problem. If it does, restart them one by one until the problem recurs. Then you know what's causing the problem.

3. When the problem occurs, work out which is the application that has grabbed focus. I have indicated previously some tricks to let you do that. If it works, this is the simplest way. Either just stop it from loading, manually disable it or replace it with a bug-fixed version.

Edited By John Cole on 15/12/2012 11:12:59

Thread: The best OSD with RTH
15/12/2012 10:36:23

Imports: if you buy from outside the Eu then you are liable for import-VAT. Parcels of total-contents value under £15 are exempt (the rules for gifts are different). You may also be liable for Import Duty, but I have never paid this.

The international-standard customs form on the outside of the parcel requires the sender to state the value. You then pay the VAT as 20% of this. Royal Mail collect the money, and charge £7 for that service.

14/12/2012 19:02:52

I emailed Dragon Labs asking about availability. Here's their reply:

"They are being held in UK customs, as soon as the postie brings the slip
so I can pay the charge they will be delivered next day - I'm hoping for
stock by Tuesday or Wednesday
Best wishes
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