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Martian03/03/2013 08:51:07
2235 forum posts
1091 photos

If you want a job doing right get a woman to do it

Danny Fenton03/03/2013 09:13:51
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9208 forum posts
4055 photos

thats impressive!

Chris Bott - Moderator03/03/2013 09:23:23
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Moderator
6668 forum posts
1382 photos
1 articles

Amazing footage, thanks Martian

Phil 903/03/2013 09:35:32
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4284 forum posts
231 photos

Of course to attempt such a thing today you would need a yellow vest

health and safety.jpg

 

Sorry my mistake the above equipment is to protect you from fork lift trucks

Edited By Phil B on 03/03/2013 09:37:13

Martian03/03/2013 14:50:00
2235 forum posts
1091 photos

yes you are right but lets face it by the time all the health and safety issues had been sorted the plane would be buried in the runway

Biggles' Elder Brother - Moderator03/03/2013 15:40:42
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Moderator
15748 forum posts
1460 photos

Ah - all well and good. But did she hammer the screws in?

BEB

cymaz28/02/2019 05:32:13
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8743 forum posts
1190 photos

This weekend the weather is shocking, time to go over the fleet ready for the summer dont know.

  • Already checked batteries and charged them throughout the winter to stop them getting critically low.
  • Re-oil, do and check tappets on the radial.
  • Linkages, servos and clevises.
  • Undercarriage and wheels
  • hard point fixings

Anything else that I’ve overlooked that might be useful question

Ron Gray28/02/2019 07:24:58
1480 forum posts
363 photos

Wires, connections and switches. Fuel tanks, plumbing, fuel filling pumps and plumbing.

Peter Miller28/02/2019 08:26:05
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10255 forum posts
1225 photos
10 articles

May I reccomend a book by Don Dwiggins called "The Barnstormers"

This lady's performance and many peoples (both men and women) amazing performances is documented with photos. One of my favoirite books

Jon - Laser Engines28/02/2019 09:15:08
4834 forum posts
180 photos

I am more or less finished with the winter maintenance on my La7. More or less everything i looked at needed some sort of attention. The issues ranged from mission critical items like worn control cables and leaking air pipes in the retracts to cosmetic things like painting the spinner and repairing cracks in the cowling.

To be honest, i just check everything i can think of!

Nigel R28/02/2019 09:30:22
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3102 forum posts
479 photos

Servo movement, slow and fast, check for dirty pots / jumpy movement / binding / excessive chattering of any type.

Quick Italian tune up before flying any ICs, including a long idle test. Hopefully will show all is well with any perishable parts in the carb.

Check edges of film covering / stickers / whatnot for any lifting or poor adhesion.

Former Member28/02/2019 09:50:01
724 forum posts

[This posting has been removed]

Jon - Laser Engines28/02/2019 09:53:52
4834 forum posts
180 photos

I always recommend the italian tune up, just make sure the engine is warm and well lubricated before giving it the big one

Cuban828/02/2019 10:00:18
2761 forum posts
13 photos

NiMh RX batteries.......charging fully and checking terminal voltage is fine as far as it goes, but check for weak/failing individual cells by performing a 1C rate (1 hour) discharge test and monitor decreasing voltage down to 1.05V/cell. ie. for a 4 cell nominal 4.8V pack, time down to an end voltage of 4.2V. If you get better than 80% capacity timed duration from a full charge (manufacturers are usually very optimistic with their capacity figures), you can be reasonably confident that all cells are functioning correctly and are maintaining balance. Anything below 80% timed capacity should be investigated by gaining access to the cells' terminals and checking on-load for a low voltage cell with a meter. A decent charger will have the facility to perform a timed discharge at the appropriate current, but you'll need a multimeter - avail yourself of the technology! I've found several of my own batteries that had lost 50% of their apparent capacity because of failing cells, but otherwise worked perfectly with the unnoticed fault just waiting to bite.

A low individual cell in a pack may not show itself when a model is flown for a couple of flights and then recharged overnight for the next session, but could catch you out when you have a marathon flying session on a really nice day with half a dozen or more lengthy flights. I wish that NiMh packs that are intended for RX use were provided with a balance lead so individual cells could be checked easily.

As I've mentioned before, beware of poor quality packs that just can't deliver much more than 1.5C in current (1.5 A for a 1000mA/Hr cells) especially with digital servos that are very current hungry. Again, use your charger to check the figures. Do you know how much current your servo installations take when operated normally or in a stalled (jammed) condition. If not, how can you make an objective judgement as to whether your power supply is up to scratch? Don't forget that all makes of radio are susceptible to low voltage and the laws of physics!

If all this saves just one model from augering in, then it's been worth the keyboard time.yes

Jon - Laser Engines28/02/2019 10:12:47
4834 forum posts
180 photos

My RX packs are 3000mah+ and i think it somewhat unrealistic to try and suck 3amps out of them. The RX wont handle that much current i dont think!

Cuban828/02/2019 12:20:56
2761 forum posts
13 photos

The Rx itself only uses a few tens of milliamps, that's very true; however, my worry is with the servos. My own tests with standard 3001 types give a stalled current of around 600mA at 4.8V, an idle current of virtually nothing and with a realistic simulated load applied, around only 200mA or so. You'd have to have a really lousy battery to get trouble with three or four standard analogue servos, even if a couple were stalled simultaneously. Unlikely on a standard sport model, but a possibilty on something unusual or unorthadox in its layout.

The problem is I believe, as I'm sure many of us are aware of, is where people go for uprated servos in higher performance models than they're used to, or even simply swapping over to digitals, and don't consider the extra performance that such servos give, will not be pulled out of thin air, they stick with unsuitable or tired packs, never test the system's actual power requirements, and wonder why they run into trouble - often blaming their radio system, unfairly.

My RX packs in my 120 size models are all 3000mA/Hr or larger and I'd be unhappy if they couldn't sustain at least 1.5C and I also test briefly at 2-3C to see that they can cope with short term high transient loads without collapsing to 1V/cell. Educated guesses - certainly, but enough to give plenty of 'headroom' and avoid brownouts. I never run electric retracts from the RX supply, or any other accessories that could perhaps fail S/C and put a large load on the RX supply e.g on-board glow drivers or nav lights that might have wiring trapped and shorted.

Not just batteries of course, but BECs that are rated at only a couple of Amps, set my teeth on edge. I'd like to see a question in the A cert test............how do you know that your model's power supply is adequate to power the installation that it's supplying? We make a song and dance (quite rightly, over range checks, correct model memories etc etc) but AFAIA ignore a critical point of safety or at least, address it in a very cursory nature.

 

Edited By Cuban8 on 28/02/2019 12:34:04

Jon - Laser Engines28/02/2019 12:40:42
4834 forum posts
180 photos

I see what you are saying but for my use case (mostly scale) i just dont load up my servos that much. I did some testing on my savox, hitec and other random servos. I found that i had to really work hard to make them draw significant current (over an amp) and while possible they did need to be completely stalled with a huge load on them. The load was more than i would ever expect the linkages or control surface to handle so i disregard it as being beyond what will be experienced in the air and not really representative of real world use.

Your point about voltage drop under load is fair though and that is why i use 6v subc as they have better current capability than AA and with 6v on tap i can suffer a complete cell failure and still be above the low voltage threshold for my futaba rx's. That said, i wont risk using the rx battery to power electric retracts as the units i have draw at least 3amps and i just dont think its worth taking the risk. All of my retracts get their own power.

Edited By Jon - Laser Engines on 28/02/2019 12:42:38

Nigel R28/02/2019 13:20:17
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3102 forum posts
479 photos

"My RX packs are 3000mah+ and i think it somewhat unrealistic to try and suck 3amps out of them. The RX wont handle that much current i dont think!"

 

Purely considering the battery, it wouldn't be unreasonable to expect that pack to handle a burst of 10A or so.

In this case you've massively overspecced your radio power source. From memory, you typically run standard size standard torque standard speed analogue servos - which are the right choice IMO for the scale warbirds up to around the 60 or 90 size - all of which are around 600 - 800mA stall current. [edit: maybe you tested 'medium torque' types, like HS485 or similar? They are just over 1A stall]

On the other hand, consider my rather contrived although perhaps not that unrealistic example -

5 juicy digital servos, on a model trying hard for minimum weight running a 4xAA pack. Or worse, a 1000mA LiFe type.

It's just had a rough landing and eaten two gear sets, but nobody noticed, or flying simply continued (yes, I know, contrived).

With two servos jammed, standard size digitals are around 1500mA stall current, there's 3A gone already, instantly drawing about 1.5C discharge (or worse in the case of the LiFe).

 

In the old days, it was easy. Everyone had analogue standard servos, and all they ever needed was 4xAA NiCads.

Edited By Nigel R on 28/02/2019 13:21:58

Jon - Laser Engines28/02/2019 13:42:56
4834 forum posts
180 photos

Most of my warbirds have a mix of standard and digitals in them. Usually 4-10kg jobs and i tested them with some futaba 148's and hitec 311's for reference. It was pretty hard to get any of them to draw more than an amp even when totally stalled. I could do it, but i would never expect them to see that much load in the air as they would have to be blown flat by the airflow for that to happen.

Again i fully expect current spikes, but i would be surprised if they were as high as 10amps and i think there is a great deal of exaggeration on this subject.

Its absolutely true that 3d models with 4 servos per aileron etc and control surfaces the size of some wings draw alot of current due to the way they are flown and loads imposed but in general i doubt most models draw significant current but. i would be interesting to check it but i dont have any equipment that would log current draw over a flight to really see what was happening.

Oh and by the rx not handling the current i meant that i think the tracks on the PCB of the RX can only handle 3amps before they melt. If anyone can confirm/deny that please do but that is the impression i was under

Edited By Jon - Laser Engines on 28/02/2019 13:44:07

Keith Simmons28/02/2019 16:22:59
446 forum posts
9 photos

I enjoyed the film clip, thank you and is it a real emergency? Looks staged to me as film cameras from 1924 are heavy and bulky and there are plenty of them from several aircraft and on the ground. Gladys Ingle is well known for doing daredevil stunts on the aircraft and is a barnstormer. She sadly passed away in 1981 at 82 years of age.

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