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Member postings for David Hall 9

Here is a list of all the postings David Hall 9 has made in our forums. Click on a thread name to jump to the thread.

Thread: Traditional thermal / electric glider kits
01/11/2020 15:55:08

Me too. I recently finished my "Inside F5J" 2.9m powered glider (Hyperflight). It was a satisfying build and it flies well in lighter conditions.

Thread: Motor Size Suggestions
31/10/2020 14:43:53

From a search on that motor, it is a rear mounted 28mm motor, 22.5 long, 41g, 1380 kv, rated at 11A.  

I guess that something around 1300/1400kv 2822 motor will be right.    

Something along these lines...  

 

 

Edit:    the image of the motor suggested didn't match the spec,  changed.    

 

 

 

Edited By David Hall 9 on 31/10/2020 15:04:04

Thread: What to do with old Lipo;s
29/10/2020 14:51:10

Presently, I carefully discharge them (they are generally failed packs, so I discharge them via the balance plug, one cell at a time using a car bulb). I remove the leads, tape them up then pop them in those battery receptacles in the supermarkets. I don't know if this gives anyone a problem, but I assume that they are dealt with by people who know what to do with them.

Thread: Get it off your chest.
26/10/2020 19:46:24

I hate it when the meaning of some words change without me being told.

"Sick" can be good, apparently. Maybe from now on, I might feel "cool" if I am "sick" (oh, there's another one!).

Sometimes, these word meanings change here on this forum too. I'm sure that "scratch built" used to mean (in model terms) that the build was from scratch..ie no formal plan, maybe an original idea for a design or a scale rendition of something. Now the term is used for some model builds from plans or even from a kit.

Perhaps when asked about my next ARTF, I will say that I built it.... after all, I added the wings to the fus.

Edited By David Hall 9 on 26/10/2020 19:46:43

Edited By David Hall 9 on 26/10/2020 19:58:29

Thread: Modern domestic heating thermostats
23/10/2020 14:28:11

Shortly after we had a new boiler fitted (with wireless control/thermostat), we began to experience odd behaviour of our system. It would turn itself on at odd times and sometimes off when we didn't change it. After a few days of this, I noticed that my next door neighbour had his boiler man in. I asked him what was wrong, he said that they had a new controller fitted and that they couldn't get it to work properly....

You might guess, when I checked his new controller, I found that it was the same type as mine and that we both had not changed it's "address" from the default it was delivered with. An easy fix that could have eluded us for longer.

Thread: Throttle trim tab - never used it - why would you?
18/10/2020 11:20:04

My F5J flying would be much more difficult without the throttle trim.

The trim on my more recent radios (Taranis on OpenTx) is actually a separate slider control that happens to be mixed with the stick function to provide a trim control.

As I don't use the trim on the throttle control for the motor, I have switched off that function. This gives me a slider control in a very good position on my Q7x (this Tx has no other sliders).

In my gliders, this slider is set up to adjustable the motor throttle to elevator mix when in "launch" mode (they tend to try to loop without some down elevator on high power), It is disabled, along with the throttle, in "glide" mode and in "landing" mode, it becomes the flap to elevator gain mix control (throttle stick becomes the flap control).

For me, it works so well that when I set up my X9D, I kept the same layout, even though the X9D has sliders.

Thread: Best interference free 2.4 tx under ?350?
25/09/2020 11:34:31

There are a lot of cheap (and sometimes quite nasty) "compatible" receivers available, particularly for Spektrum protocols. There may be a tendency to blame the Tx make as problematic when it may be the Rx copies.

Although in my club, many members use one or two popular, cheap Spektrum compatible receivers, my own experience on the bench caused me to bin the two that I had. It wasn't the Spektrum system that was a problem, for me, it was poor PSU noise immunity (brown-outs).

Thread: Wrong receiver being controlled?!
05/09/2020 10:10:42

The receiver number is not related to the model memory number. It is set up on the first page of the model config. On my Taranis, using D8 mode does not allow a receiver number to be selected.

Some of my telemetry enabled receivers do want to set a number and will warn if I use one that is already assigned.

As far as i know, what you have is normal.... be careful, many have flown the "wrong" model with the expected consequeneces.

Thread: Accident waiting to happen?
02/09/2020 16:29:37

I'm guilty of storing batteries in this way at home, where they are grouped into size ranges.

It's just developed like that.. Thanks for the prompt, I've ordered a metal tool box that has several trays. That should be a better home storage solution than the cardboard boxes I presently use. At the field, I keep them in a padded case (camera case).

Incidentally, have you all seen the test videos of "LiPo safe bags"? They may be not much safer than that plastic tray.

Thread: Refridgeration expert needed
25/08/2020 20:36:35

Isn't the tray there to collect water from the auto defrost cycle? it is intended to evaporate in the tray, I believe.

Thread: What ESC for damped starting and stopping?
25/08/2020 16:53:55

Thanks to all for the suggestions.

I found this nice discussion on the braking options for BLHELI_32. It allows variable damping, apparently. 

Regenerative braking...wow! 

So, a BLHELI_32 device seems to be a good way to go rather than the more limited BLHELI_S.

Configuring the _32 is the next problem.... but that's another thread, I guess.

 

 

 

Edited By David Hall 9 on 25/08/2020 16:56:46

24/08/2020 19:17:02

Thanks for your suggestions... I use OpenTx on my Taranis Tx, so could set up a slow response for the throttle.

My mixes for my F5J gliders are fairly simple, but there are a lot of them, making it all look complex. The throttle is run from the throttle stick. I use flight modes, so in one mode (power) the throttle stick is CH1 (THR), in the next mode, it is not assigned to any channel and in landing mode the throttle stick is the flap control via CH6 & 7 (FLA) (and CH8/9 in one plane).

A delay can be programmed in, but some very odd things happen when switching modes if a delay is configured. In one case, the throttle "blips" when it should have been off (-100). This is enough to get disqualified from that round as it is seen as a throttle use during the comp. However..... if the altitude/timer device (AltisV4+) switches the throttle off at the configured time or height, this will also be instant, so whatever has been set up in OpenTx is made redundant. .. so it is far easier to use an ESC soft start/stop than to have to deal with a whole bunch of config stuff that might not be possible to fix.

There are several OPTO ESCs available at the moment. I can program a BLHELI_S via a Naze32 but I might struggle with a BLHELI_32 as (I think) different hardware is needed to use the "passthrough" facilty of Cleanflight.

Does BLHELI_32 offer better functionality than the S for start/stop functions?

 

Edited By David Hall 9 on 24/08/2020 19:18:53

24/08/2020 11:02:28

I would like to find an ESC that will be better for my F5J type gliders than my present devices.

The ESC will draw 40-50A and, as they have a folding prop and drive through a gearbox, would be better to have a soft start option. As they have to brake when stopped, the normal braking on budget ESCs tends to be quite severe, so some softening of the braking will be needed.

I realise that many higher end ESCs might suit this use, but I'm looking for cheaper options. For other reasons (battery backup and weight reduction), I would chose an OPTO ESC.

The obvious choice is a BLHELI / BLHELI_S / BLHELI_32 ESC.

I've used some small BLHELI ESCs in my smaller gliders, but these are now pretty well replaced with BLHELI_S and BLHELI_32 devices, the S variant also becoming more rare.

Is there a preference for S vs 32 for my use?

Thread: Help with continuity testing
22/08/2020 12:49:58

If I understand your concern correctly, you did not expect apparent continuity between the supply output (+) and the 0v or earth connections.

The output circuitry of power supplies and in particular switched mode supplies, have plenty of circuitry to eliminate noise from the final output. To a low power DC meter, this may look like a path to 0v (or earth). A very simple power supply is likely to have capacitors on the output. Your meter may well indicate a near short circuit as it supplies current to the capacitor as it charges from your meter and more so as it leaks to 0v via some of the filtering circuit.

 

The continuity function of meters are great for checking the continuity of wiring and for checking the operation of some devices like diodes.

 

Edited By David Hall 9 on 22/08/2020 12:50:35

Thread: Looking for an electric glider
10/08/2020 19:30:59

I found that the Blejzyk ARTF kits (maybe not enough building for you) are very high quality. My latest is the Mefisto, a 1.9m model that I built as a windy sports model.

Thread: 5.5v too high for MKS servo?
05/08/2020 16:43:23

The spec is a little contradictory, rated at 4.8v NIMH battery or 5v BEC, where the NIMH battery will be significantly higher than 5v at times. What limit to apply?

As I had the parts in hand, I have added a diode in series with the supply to the RX. I used a diode rated at 15A (still physically small). I had measured the forwards voltage drop as near to 400mV, so may work well here, giving a supply voltage of around 5.1V.

I have tried it, it works.

I was surprised find that the servo that had odd behaviour is now as near perfect as it could be.

For info... when the stick (aileron in this case) was moved from its end stop to the centre, as fast as I could, it sometimes overshot the centre by a noticeable amount, hesitated for a fraction of a second, then centred. All slower movements over the full range were fine. I cannot make it do this, now the voltage is lower.

Thanks to those that suggested that the spec should be adhered to.

05/08/2020 12:41:15
Posted by flight1 on 05/08/2020 12:05:56:

a short answer is yes you are risking it. The manufactures states

NOTE: Use with 4 cell Nicd/NiMH battery or use UBEC (4.8V~5.0V)

as quoted from MKS site

it's all red type How??

Edited By flight1 on 05/08/2020 12:07:13

Thanks for repeating the spec to me.

I run another glider on 5.5v (most budget integrated BEC/UBECs over 40A rating have a 5.5v output), this has had no issue.

I wondered if anyone has actually blown a DS6100 on 5.5v?

On the other hand, this will facilitate my future plan to add a diode in the output to allow the use of a backup battery.

05/08/2020 11:09:28

I have fitted a 5.5v SBEC/ESC to my F5J glider. This has several MKS DS6100 servos fitted. It seems to work well except for a later model servo recently fitted to replace a faulty servo. It can behave oddly near the centre when the stick is centered from full movement quickly.

In a separate job on the same plane, I was planning to add a battery backup system and had to look up the low voltage limit for theses servos. I was surprised that the specified higher voltage limit is 5v.

Am I risking a failure of the MKS DS6100 by running at 5.5v?

 

 

Edited By David Hall 9 on 05/08/2020 11:09:43

Thread: V tail question
31/07/2020 10:12:41

I've found that it's quite easy to inadvertently use rudder trim to correct (in part) an aileron imbalance for level flight. This is more so in my gliders that have a small dihedral and will turn on rudder, such as my thermal type gliders. Models that are insensitive to rudder might allow some imbalance to go fairly unnoticed.

The test that I perform is to pull a loop from a gentle unpowered dive, with enough energy to complete the loop, and to correct any tendency to screw out of this by rudder trim. This assumes that it is trimmed for level flight to start with. I understood that this is quite a standard test.

Thread: How bad can things get
29/07/2020 10:53:04

When you get it back, you will inevitably be in the position where you will have to "try it again". Goodness knows if or how many crashes you could have just to confirm a fix. I'd run very extensive tests without flying and then some in a very basic airframe.

In the meantime, I'd be tempted to buy one of the multi protocol transmitters or a Taranis with plug in multimodule, then you can run all your old RXs.

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