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Member postings for Gary Manuel

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

Thread: Spektrum DX6i Throttle issues
26/01/2020 16:05:13

Carlos.

I don't fly helis but I do fly quads. I set my failsafe on my quads to cut the motors immediately. My thoughts are that a quad falling from the sky can only impact once and it will be directly below where I was flying - which should be over an empty field and therefore safe.

Thread: Upgrading Windows7 to Win10 for free
26/01/2020 14:13:00

I see what you mean Dick. Not as simple as it first appears then. I think I'll stick with XP!

26/01/2020 12:57:52

kc - instructions here. You probably already have a suitable USB stick. All required files freely available.

Let us know how you get on. I might have a go.

Edited By Gary Manuel on 26/01/2020 13:01:30

Thread: Spektrum DX6i Throttle issues
25/01/2020 13:47:45

 double post

 

Edited By Gary Manuel on 25/01/2020 13:48:16

25/01/2020 13:46:59

Good point Peter. I don't fly helicopters so I'm not sure how faisafe should be set.

I'm pretty sure that it should not be set to throttle up with the copter sat on the ground though. Whatever the intended failsafe is, it should always be tested and not just assumed that it will behave as expected.

Oh and to clarify my previous post. I meant that I disagreed with the "Otherwise ☠️☠️😂😂" part, not the order that the Tx and Rx should normally be switched on and off. Apologies if what I said was misleading. I do maintain that switching the Tx off (or losing the signal!) with the Rx switched on should result in a safe situation and must be specifically set up and tested. That's what I was getting at.

Edited By Gary Manuel on 25/01/2020 13:48:53

25/01/2020 12:34:50
Posted by Colin Carpenter on 25/01/2020 12:23:51:

Always disconnect Rx/model before turning off tx ! Otherwise ☠️☠️😂😂Colin

I disagree. In fact, it's a mandatory safety test at our field - to test that the fail-safe is set right.

Obviously hold onto your model whilst doing it - just in case fail-safe is wrong way round!

25/01/2020 12:15:47

Carlos. wrt to 2nd question. It sounds like your fail-safe is set up with the throttle at 100% rather than 0%.

Have a read up on setting the fail-safe.

edit - If using spektrum receivers, it probably just means re-binding with throttle down. Let me guess that you have reversed your throttle servo in your transmitter since you initially bound the model.

Edited By Gary Manuel on 25/01/2020 12:18:27

Thread: 6 Turning 4 Burning
22/01/2020 12:48:50
Posted by Manish Chandrayan on 22/01/2020 12:23:26:

The four burning are in the under wing pods (2 in each pod) that have the red and white stripes

Yes, they appear in the very first frame of the video.

Anyone know whether the burners and turners used the same fuel?

22/01/2020 11:48:40

I'm unfamiliar with this aeroplane and couldn't make out where the "4 burning" are from the photograph - although it's impressive enough with just the "6 turning"!

I googled it and immediately found this video - wow! .... and look how many of them there are on the ground!

This will be a hell of a project.

Thread: Theory of the operation of a servo
21/01/2020 13:50:38

I agree Pete.

The video and my attempt at explaining it support everything you've said.

21/01/2020 12:24:41

Nigel - yes I agree that digital servos process the incoming PWM signal differently - and different manufacturers might process it differently.

Apologies again if this gets a bit heavy.

Perhaps I wasn't clear about how I believe the average voltage is increased by the output waveforms shown on the oscilloscope. Ignore for a moment that the 300Hz output is split up into pulse trains and assume that it is just one pulse every 3.3mS with a variable mark/space signal.The average output voltage is increased by repeating the output pulses during the time that an analogue servo would have stopped outputting. Repeat it 5 times and the average voltage becomes 6 times greater.

The benefit of repeating the initial pulse only applies up to the point where the "analogue" pulse runs into the start of the second pulse after 3.3ms (at about 1/6th of maximum demand).

Now consider the pulse trains. Lets say there are 60 x 53us pulses per 3.3ms train. Apply the same principle of repeating each pulse and the average voltage is increased by 60. Don't forget that this is already being multiplied by 6, giving a total multiplication of 6 x 60 = 360. Again, this option of repeating the 1st pulse only applies until the 1st pulse runs into the 2nd after 52us.

So I say that for tiny inputs of less than 1/360th max, a digital servo can give 360 times more power than an analogue. Between 1/360th max and 1/6th max, it can give 6 times more power. Above 1/6th max, the power output would be pretty much maximum. This assumes that the microprocessor is not making any adjustments to the actual width of the pulse (which it could well do).

I stand to be corrected, but this is my interpretation of how a digital servo works and of what is being seen on the oscilloscope.

Edited By Gary Manuel on 21/01/2020 12:29:57

20/01/2020 21:21:04

Apologies in advance to anyone of a nervous disposition, who might find this a bit scary

The problem I have with all the definitions of "analogue" versus "digital" servos I've seen (including the above links) is that they just state that analogue servos work at 50Hz and digital servos work at 300Hz, without explaining what that actually means.

The following video might help to put the difference between "analogue" and "digital" servos into perspective. It shows the actual voltage being applied to the motor - as measured on an oscilloscope.

What the video doesn't go on to emphasise is the average (or RMS) voltage being applied to the motor by each type of servo, which is actually the most important bit, as this controls the speed / power at which the servo will move. I have yet to see a video or a report that actually ties it all together, so I'll have a go.

An analogue servo applies a narrow pulse every 20mS (50Hz), with a mark/space ratio (on / off ratio) according to the required motor movement. Average this out and the voltage is variable, according to the required motor movement, but quite low for small movements - and therefore quite slow to respond.

The digital servo on the other hand, applies narrow pulse trains every 3.3mS (300Hz), but not just that! The pulse trains are made up of even shorter pulses of 53uS (19kHz) which vary in their mark/space ratio according to the required motor movement. Average these pulses out and the voltage would be much higher than the analogue equivalent - and very much quicker to respond. And the important bit is that the gaps between the 20ms pulses of the analogue servo have almost been filled in, giving a much higher average motor voltage - and much faster response times.

I hope this makes sense and helps distinguish analogue and digital servos.

 

Edited By Gary Manuel on 20/01/2020 21:45:21

Thread: Antonov AN124 Ruslan
20/01/2020 19:25:13

I'm sorry Simon, but that thing looks like it will never get off the ground. Massive great fuselage and wings like a bumble bee.

Great job - just like the real one!

Thread: Recommendations please
20/01/2020 12:00:49

I wouldn't recommend fast charging Nimh's.

Thread: Dash cams
18/01/2020 13:24:42
Posted by David Hall 9 on 18/01/2020 10:30:49:

...... in many cars, there is a 12v feed to the mirror area, usually to power a light or something that is turned on with the ignition. There's also usually plenty of space behind the light cluster, so I have fitted a BEC to those connections and poked the end out to the mirror area. It works very well and is as neat as you could wish for.

Good idea. I bought a dedicated hardwiring kit for about £20, which converts the cars 12v supply to 5v as required by the camera. A BEC should work just as well - and most of us will have at least one to hand.

17/01/2020 23:48:18

I use a NextBase 512GW. Very Good picture quality and features. This has a Sony sensor and glass lens with polarising filter to reduce reflections from the windscreen - which really make a big difference. Good price on Amazon at the moment. It has GPS which allows you to playback recordings onto a google maps / screen image using PC software. Newer models may be better but this is good for this money.

Only problem we've had is that the internal battery is failing after 3 years so it doesn't record for the time it should after the ignition is switched off. Just ordered a new battery (4 batteries for £4.50 actually), so it will be back to normal soon.

Thread: CAA registration take-up?
17/01/2020 22:07:24
Posted by Colin Carpenter on 17/01/2020 10:32:10:

We must all be asking the same question? Where have they all come from bearing in mind I thought there were only 40k of us old farts flying!! Colin

No - there are 40k old farts who have voluntarily joined UK clubs and associations.

There are many more old farts out there who did not see the need to join clubs and associations, but were happy to fly in their local parks without insurance etc. They were doing nothing wrong and were flying quite legally.

The law has now changed and they want to carry on flying legally. £9 is the sum total of their annual outlay to keep the law off their case. I have spoken to a number of them in our local park and they consider £9 a small price to pay. It's not a big deal to them.

Thread: Best Heating Option For Your Hobby Shed
13/01/2020 18:27:39

@SR71 - you need to pair the remote controller to the heater.

Have a look HERE.

Thread: Upgrading Windows7 to Win10 for free
13/01/2020 12:57:22

Updating to the latest version is not always the best thing to do chaps - especially if your computer wasn't designed for it. You might just make things worse than they are now.

I have an old Laptop that I only use for CCTV capture of a Nest-Box camera via a radio link. It was initial set up for Windows XP, but I updated it to Windows 7 a number of years ago. It was never quite happy running Windows 7 and due to the usual regular Windows 7 updates the Laptop had slowed down to a crawl. Only last week, I decided to rebuild it from scratch. I used Windows XP Pro SP3 (POSReady) - 32 bit version. POSReady is the name given to the version of XP that was supported by Microsoft in systems with embedded operating systems (ATMs, Cash Registers, Supermaket tills etc) beyond the XP end of life date. It runs perfectly now because it's not struggling with an operating system it wasn't designed for. The best bit is that because MS are no longer supporting XP, there should be no future updates to slow it down smiley.

It might become susceptible to new virus attacks in the future, but who's going to waste time writing them for a system which has officially been unsupported for over 10 years? I only switch WiFi on when needed as my Laptop has a convenient external switch.

Video HERE shows how to get XP updates until April 2019 (maybe beyond?) for anyone who wants to try it. I used an alternative method, which I can't share on here.

Edited By Gary Manuel on 13/01/2020 12:59:16

Thread: Chris McG F-86 Sabre Dog build blog
09/01/2020 19:28:31

Very tidy Chris!

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