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Member postings for Andrew Ray

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

Thread: Airline Acronyms
24/09/2012 07:24:33

ETOPS, to allow twin engined jets to fly long distances over water.

Also known as Engines Turn Or Passengers Swim.

Thread: Airbus disaster
20/09/2012 13:25:30
Posted by Mark Agate on 20/09/2012 08:51:48:

Hanging on the up is a classic novice RC pilot's mistake. I would have thought there's a good case for forcing full-size pilots to learn to fly models first - that surely would have made the inexperienced pilot realise he was doing something wrong.

Hmm, not quite right there, all commercial pilots have flown light aircraft and will have done stall/spin awareness, certainly into a fully developed stall and then to recover. Conventional commercial jets have a stick shake which is an awareness of approching stall if the crew have missed reducing airspeed, nose high attitude and a reduction in airflow noise. If the stick shake is ignored then stick push will activate where the control column is pushed forwards thus lowering the nose, the autopilot is designed to disconnect at the stick shake. I think the difference with Airbus is the way in which the comuters fly the aircraft, I am of the understanding that an Airbus will not actually stall because it has a high alpha protection system.

Airbus computer logic has resulted in some accidents, notably the Air France aircraft that ended up in trees at the Paris Airshow many years ago, the crew commanded Take Off/Go Around thrust at the end of their low pass and the aircraft did not respond but instead mushed into trees. The interface between man and machine has in the past been through a mechanical means that man easily (?) understood. Now the man in part has to understand how the computer will interpret his input (because of safety protocols in the system) which in an already confusing situation will only serve to add to it.

If this had happened to an aircraft with conventional controls I am sure the crew would have recognised the onset of the stall before the stall ocurred and would have been able to control the aircraft.

Andrew

Edited By Andrew Ray on 20/09/2012 13:26:35

19/09/2012 23:20:21
 

The crew still had attitude reference, an altimeter and engine indications. It is not difficult to fly with unreliable airspeed (after this incident flight with unreliable airspeed became the hot simulator topic). For a given thrust setting there will be a pitch angle that for a weight will give level flight. In this case the pilot's did not recognise that the aircraft was in a stalled condition.

The pitots supply indications primarily for airspeed, the conditions this aircraft entered were very unusual and normally at the temperatures at these altitudes supercooled water does not exist but it did and as soon as the supercooled water (water existing at a temperature below the normal freezing point of water) meets a solid particle it freezes. Apparently pure water will remain as a liquid many degrees below zero. Usually there are enough microscopic dust particles for supercooled water droplets to form ice crystals but not in this case and the supercooled water froze on contact with the heated pitot probes, they were not designed for such an environment as it was not thought that these conditions existed.

As far as the crew losing control, all I can say that despite the best speculation, if you are in that situation it will be incredibly disorientating, it's dark, in turbulent cloud, auto pilot drops out, warnings going off and loss of control. I suspect that had the aircraft been fitted with conventional controls the pilot's may well have realised and centered the control column. As it was with one pilot holding the side stick back the more experienced crew member didn't realise this. It was apparent that due to the stress of the situation standard procedure was not followed. There was not a positive "I have control" call and "you have control" response.

Who knows until you are in that situation what the outcome will be?

Andrew

Edited By Andrew Ray on 19/09/2012 23:24:54

Thread: What happened to the Diesel Engine
17/09/2012 15:02:11

I have fitted a PAW .60 TBR to an ARTF Acro Wot. Only one flight so far so too early to tell as it's still running in. At the moment the noise level is somewhat on the high side. Throttling seems ok. Fuel is pricey and not too pleasant to use.......but the aroma is something else.

Thread: Glitches when using 35Mhz with electric
10/09/2012 22:04:15
Posted by Simon Chaddock on 10/09/2012 11:49:15:

Eventually overloaded the ESC so replaced it with a 40A and during a bit of a rebuild moved it as far apart as possible from the radio, about 6", with longer battery leads and shorter motor wires.

Result? no end of glitches when under power but ok when gliding. Changed the motor, the radio and the run of the aerial. It made no difference. My suspicion fell on the ESC although it functioned perfectly.

In desperation I returned it to close to its original configuration of motor and a new 30A ESC right alongside the radio. No glitches!

I seem to remember that the general rule some years ago was that it was ok to lengthen leads from the ESC to motor but not the battery leads, they should be as short as possible. Sounds wrong as one would think that noise would come from the motor leads. Anyone else remember this?

10/09/2012 11:34:13

I have flown electric for a number of years on 35meg and never had a problem with electrical interference, I have used Micron home built rx's and JR rx's. I always placed the rx as far behind the motor, speed controller and battery as possible.

In fact at the moment I have far more confidence in my 35 meg gear than 2.4.

Andrew.

Thread: Becoming a qualified commercial pilot.
08/09/2012 05:56:07

Phill

I have been flying commercially since I was 37. It is not easy to achieve and in the end it depends on just 3 things, will you pass a class one medical, if not then don't spend money as this is a pre-requisite. Can you raise the money? Lastly how determined are you?.......that's assuming you are reasonably well coordinated.

PM me if you want a chat but speak to as many people in the industry you can, that way you will be able to form a balanced opinion.

Oh and PPrune is a rumour network so be wary what you learn on there as wannabees, spotters and the rest can post on there.

Andrew

 

Edited By Andrew Ray on 08/09/2012 06:00:22

Edited By Andrew Ray on 08/09/2012 06:03:29

Thread: New Poll - Has the recession had an impact on your hobby?
04/09/2012 11:54:04
Posted by Tony H on 04/09/2012 10:36:56:

Hi David, looks like you have missed one.

i.e

6. I buy more Artf/build kits than ever before at recession prices - this would be me

Me too, because I have started doing more flying.

Thread: Motor Shaft Removal
02/09/2012 14:24:16

PatMc, yes I did want to remove the shaft as there was only one circlip recess and by pushing the shaft through there was nowhere for the circlip to fit. Replacement shafts have two slots and that's what I am fitting. Having said that thrust from the prop would hold the motor together whereas in a standard bulkhead mount the circlip is needed to hold the motor together.

01/09/2012 17:56:37

Shaft is out of the Turnigy using the vice method, I placed a couple of large washers inside the bell before inserting the socket to spread the load evenly. When I come to replace the shaft I will leave the shaft in the freezer overnight to shrink it and warm up the bell to expand it as the shaft was incredibly tight in the housing. I'm not sure the grub screws do much, there are no witness marks on the shaft.

Thanks for the advice guys.

01/09/2012 11:19:12
Posted by Mark Powell 2 on 01/09/2012 11:04:54:

I assume you want to turn it round so that you can attach the prop adaptor to the bell rather than the shaft. Some turnigy motors are supplied with such an adapter. But they won't fit anyway. Some of their motors have only two screwq holes on the bell and curved 'non hole' arms so the adapter wobbles about. Been on another thread.

So check that before you bother at all. If that is what you are doing.

Instead of the motor mounting on the firewall/bulkhead it mounts on the front of the nose (cowl) so the shaft needs to protrude through the stationary (fixed) part of the motor, in that way a standard prop adaptor will fit. I think that makes sense.

01/09/2012 11:15:52
Posted by Martin Harris on 01/09/2012 11:03:54:

I'd recommend the vice method - hitting the shaft is much more likely to damage the bearings.

I have separated the motor so the bearings are in the armature not the bell

01/09/2012 10:55:45
Posted by Bob Cotsford on 01/09/2012 10:38:03:

or find a deep socket that fits inside the bell and use the vice to press the shaft through. The socket transfers the pressure to the area around the bearing and saves risking distorting the bell.

Didn't think of that. I have been concerned that I could damage the end of the bell if I belt it too hard.

01/09/2012 10:53:37
Posted by Mark Powell 2 on 01/09/2012 09:39:55:

Blood, sweat, but no tears. A little heat. Put the motor bell resting on a vice jaws with the shaft facing the gap. Tap with a hammer, A metal one, putting wood blocks as a shock absorber spoils the effect, you can file the burrs off later.

Done that, hit it as hard as I dare, maybe I need a bigger hammer.

01/09/2012 09:31:21

My Eflight Hurricane hit the ground pretty hard and bent the motor shaft. I pulled the motor out of the airframe and started to remove the grubscrews holding the shaft. They were very difficult to remove and secured with a thread locking compound, one grub screw came out with a bit of persuasion and heat, the other would not budge despite trying all the tricks, I even broke an allen key trying to remove it. In fairness Horion Hobby were very good, I returned the motor to their service department and received a new motor by return.

In the meantime I purchased a Turnigy motor and needed the shaft to poke out of the other end. This time the grubscrews came out easily but try as I might I could not shift the shaft, it was solid in the housing.

Has anyone had any success removing stubborn motor shafts and how have you done it?

Andrew

Thread: . . . anti social nature of ic activity . . . ?
01/09/2012 09:02:19

Can you imagine anyone displaying a Turnigy whatever thumping great leccy thing in a display case next to an OS IL-300 or an Oliver Tiger or a lovely Laser?....no I thought not, (no doubt someone will say otherwise just for the hell of it)wink

Me, I have powerless planes, electric, glow, diesel and petrol, point is I enjoy them all, favourite? It's the one I'm flying at the timesmiley

Andrew

Thread: Buying Expensive Gear from Forum Adverts
01/09/2012 07:01:23

Well, in the end after a few heated emails (I had pulled out of the deal on the basis of lack of information) the seller then said he was prepared to accept PayPal. I read the conditions for using PayPay outside ebay and was happy to pay the charges. The engine arrived safely. I think my initial doubts cropped up because both myself and the seller were being somewhat cautious which led to an initial misunderstanding.

Andrew

Thread: Acro Wot ARTF (balsa) chat
30/08/2012 09:06:08
Posted by Biggles' Elder Brother - Moderator on 29/08/2012 23:26:18:

Saw one of these flying for the first time tonight - I see it still fishtails at high speed!

BEB

Why does that happen? I had a Micro Mold Spitfire that would fishtail, it's not prop wash as it was not fitted with an engine, I flew it off the slope.

My old ARTB Acro Wot does not do it and I didn't notice any fishtailing on my ARTF Mk 2 even though I put it in a high speed dive.

Andrew

28/08/2012 20:21:30

I flew my Acro Wot with the PAW 60 today on a 15x6 as recommended for running in, knew I'd forgotten something....my other propscrying

Still it flew but the conditions were not brilliant with 20kt gusts. My impression was that a smaller prop would be better, maybe a 13x8 APC rather than the 15x6 Master that was fitted for running in.

Andrew

Thread: F27Q Stryker motor noise
27/08/2012 22:03:09

I've just spun my Stryker motor by hand, it makes a slight noise but nothing I wouldn't expect.

Trouble is, you get used to the noises around you and when someone points out a noise it may be perfectly normal, it's just that you have not noticed it before......and that's when paranoia sets in.

On the other hand........

Andrew

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