1. Parramatta Radio Control Aircraft Club
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  using a gyro with a Radiomaster 4in1 tx

Posted by: greggold
03-01-2024, 12:51 PM
Forum: General
- No Replies

I do not fly with a gyro, however I noticed a post about how Volantex 40cm span models that have a gyro (and come with a basic tx) can also be flown with a RM tx that is 4in1 tx, or module. Bill Clark goes through how its set up for the Volantex 761 planes, its a little complex but probably a good idea for these models.  

The vid is called 
EdgeTX Setting up the gyro function in a foamy park flyer
Its shown for the volantex 761 6 rc airplane

https://www.youtube.com/watch?v=pjkv3Xsn6BI&t=92s

I took a screenshot of the details of settings that Bill showed on-screen, but the picture would not upload to this website (I have previously noted the website can be unable to accept uploads for a period).

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  Fuzzy understanding of RC signal and dynamic power

Posted by: greggold
29-12-2023, 12:19 PM
Forum: General
- No Replies

Recently I posted a question on RCG about dynamic power jumps that occurred in 2 flights. The resulting discussion cleared up a number of fuzzy understandings I carried about the RC signal. Now we have elrs, not only are there no control signal problems but the RC signal can be understood in much greater clarity.

You can read the long version on RCG #2431 and following:
https://www.rcgroups.com/forums/showthre...em/page163


Here is a summary of the discussion. The question was about dynamic power: why do we occasionally see a TPWR jump while the RQly remains normal? (see plots attached, where Edge plot 2 is a zoom view of plot 1).

I was perplexed because I did not have a clear understanding of my radio signal. In the discussion it became clear there are 2 sorts of packets in the radio signal, control packets going from the tx to rx, and simultaneously telemetry packets going from the rx to the tx (I kinda knew it but not the key details... a bit fuzzy).
A telemetry packet is 10 ms and a control packet is the same duration. The following calculations are for a typical airplane elrs setup of frequency 100Hz, telemetry ratio 1:32.
We can convert frequency units from hertz to millisecond (period), given that 100 Hz is 1000 ms or 1 second. If all the signal comprised telemetry packets, then telemetry would arrive at the tx at a rate of 1000/10 or 100 packets per second. But telemetry is only 1/32 of the signal. While the control packets are arriving at the rx at almost 100/sec,  the telemetry packets are arriving at the tx at a rate 100/32 or 3.12 per sec.

Jumps may be triggered by drops in RQly, OR by falls in TQly (also by falls in RSSI and RSNR). See
https://www.expresslrs.org/software/...ransmit-power/
for a full discussion.
TQly is the percentage of missed or faulty telemetry packets arriving at the tx.

When Landru did a plot of TQLY and TPWR on data from the plotted Edge flight
the cause of the jumps was revealed (plot attached). The TPWR jumps correspond exactly to drops in TQly. The drop in TQly percentage is 4% (to 96%) for the 50mw TPWR jumps, and 8% for the 1000mw jump (attached) - in the Edge 16 plots the TPWR is divided by 2. This explains how dynamic power jumps occur with normal RQly.

Until now I had no idea I should be checking on TQly in my write logs.

When reading about packet rate, or watching online gurus, it is essential that we always be clear which packets are being discussed, rates are different for the control packets going from the tx to rx, and the simultaneously transmitted telemetry packets going from the rx to the tx.

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  major 3D aerobatic manoeuvres

Posted by: greggold
27-11-2023, 05:14 PM
Forum: General
- Replies (3)

In this video Michael Wargo introduces the major 3D aerobatic manoeuvres.

https://www.youtube.com/watch?v=8f-NFMy_UqE

The details of the manoeuvres are only briefly explained by Wargo, but the list and selections are good. A quick google search on each of these names provides several videos that illustrate/demonstrate each manoeuvre in more detail. For example, for knife edge spin, I like 2 of many google search suggestions :

https://www.modelairplanenews.com/5-easy...ge-spin-2/

https://www.youtube.com/watch?v=ifbNaHtZ5bw


Harrier
Knife Edge
Rolling Harrier
Hover
Hover with Torque roll
Snap Flip
Inverted flip
Pop top crankshaft
Waterfall
Knife edge spin
Flat spin
4 point roll
Blender

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  Discovery of "new" RC brand

Posted by: greggold
04-11-2023, 01:25 PM
Forum: General
- Replies (1)

Aloft Hobbies (the US distributor of Frsky) drew my attention to a new (to many) RC brand, Causemann GmbH & Co KG (actually its been around for years).

https://forum.alofthobbies.com/index.php...dium=email

Aloft are excited about the almost-circular flying saucer Alix model (photo attached).
Alix maiden:
https://www.youtube.com/watch?v=tCgKWp_VyUc

However I am looking at the Ozalis and the Sambah, which are 83 cm span 3D planes (3D planes are called shockflyer in Germany)
https://shop-rc.causemann.de/Der-unzerst...Sambah-EPP
Ozalis costs euro 25.50, and Sambah 27.90

Sambah: "Made from 5mm EPP RG20, this means you can achieve almost the same take-off weight as with a shock flyer made from 3mm Depron.""

This video of Ozalis has it fly with a 3S 450 mah 50C lipo, and weight of 203 gm

https://www.youtube.com/watch?v=BnlC839FzrY

The control link gear is sold separately
https://shop-rc.causemann.de/Anlenkung-S...etc-GFK-V2

This site shows some details of the pull-pull linkage arrangement, including how to adjust the thread tension.
https://shop-rc.causemann.de/5mtr-hochre...ngshot-HLG

Most 3D planes eg Twisted Hobbies use long pushrods for ele and rud that are supported by tiny plastic guides. For commanding up elevator, its better that you arrange the servo so it pulls on the pushrod to give up ele, because when you push with the rod there is some flexion even with all the guides. In theory a pull-pull arrangement with thread used in the Causemann planes avoids this issue to achieve more precise control. 

In my experience 80 cm 3D planes can be flown in local parks, although I already have a few, I may try an Ozalis or Sambah.

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  Gaoneng 2S HV lipos

Posted by: greggold
19-10-2023, 03:59 PM
Forum: General
- Replies (3)

In the time of lipo shortage, I tried a new brand from PhaserFpv:
GNB GAONENG 650mAh 2S HV 7.6V 120C XT30 LiPo Battery FPV Drone Racing Light Weight LiHV High Voltage

I have been using these lipos to power several 80 cm span 3D planes for some time, and I have assumed being 2S lipos that they should be charged to 4.2 v per cell, total 8.4 volts. I think they perform well.

I today noticed they have a nominal voltage of 7.6v! Until now I have never seen a lipo with a "nominal voltage of 7.6v".

I posted a question on RCG:
On the website it seems all the Gaoneng 2S batteries have a nominal voltage of 7.6v. There is no advice on what voltage they should be charged to. I would appreciate if anyone can explain this. Can they be charged like all other 2S lipos are charged?

Fortunately I received a good reply. The above battery is not called a lipo, its a LiHV, which can be charged to either 4.2v per cell or 4.3 v per cell. It looks the same as a normal 2S lipo, and it performs well.

Oscar Liang provides useful details on LiHV.

https://oscarliang.com/lihv-lipo-drone-battery-hvli/

I plan to check my chargers whether they accept LiHV batteries, or whether they can accept a charge to 4.3v per cell.

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  Frsky Tandem X20 tx and R10 rxs for sale

Posted by: greggold
11-10-2023, 03:45 PM
Forum: For Sale
- No Replies

SOLD

I am selling all my Frsky gear so I can focus my attention on one RC protocol. All the gear I have is in perfect working order.

I prefer to sell everything in one bundle.

The Tandem X20 tx is on sale for $320. 

There are 5 Tandem R10 rxs, 2 of which are new and unused. The new R10s $35 each, the used R10s $25 each 

2 R9 Slim rxs each $30

FrSky S2F.Port 2.0 Protocol Converter  $15

FrSky STK Tool for S.Port products Upgrading and S6R/S8R receivers Configuration  $10

The total value is $550 if items are bought separately. The entire bundle can be purchased for $450.

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  Assessing the condition of a lipo

Posted by: greggold
05-10-2023, 10:14 AM
Forum: General
- Replies (3)

John Hopke (in my opinion the best of the online RC bloggers) has a new video that shows how to assess the condition of your lipos.

The idea is you measure the number of mah during a discharge that goes from 4.2v to 3.6v, using a 2C current. This number should be above 85% of the nominal capacity, if not, he recommends discard the lipo.

The video shows a dedicated RC discharger being used to measure the percentage of nominal capacity, however I think most lipo chargers (that can discharge) can give you the measurement (of mah required to discharge).
The video is doubly worth a look as it explains several important points, such as why the discharge stops at 3.6v.

https://www.youtube.com/watch?v=PwvI5I2x900

The testing has a focus on 4S or 6S, 4000mah capacity lipos, and I think the smaller lipos I use (3S, 1000 or 1300 mah) may have higher internal resistance, and possibly should have a discard figure of 80 and not 85%.

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  Ultimate 3D aerobatics trainer

Posted by: greggold
03-10-2023, 10:48 AM
Forum: General
- Replies (2)

I am not a fan of RC simulators, and prefer whatever RC time I get to be expended at the field. However I have dabbled with flight sims (on a mac only a limited range of sims are available, the one I have is AeroflyRC9) and one of my favorite models is a indoor F3P aerobatic model called Elanor. Its the best aerobatic trainer you can imagine, allowing the pilot sufficient time to apply correct controls for each manoeuvre. You fly in a different flight regime where the balance of gravity and drag are altered. 

Yesterday at McCoy I saw an Elanor-type model in action, it is an original design, built and flown by Steve. Its a brilliant plane.

Here is an original Elanor in action in 2014. It has 2 counter-rotating props.     
https://www.youtube.com/watch?v=hHP5JF3k1bw

Here are various F3P vids:
https://www.pauzuolis-rc.com/events-list...-in-alytus
(you have to scroll down to locate the videos)

In  RC Groups there are threads and a forum for indoor aerobatic models, with posts mostly consisting of people searching for suitable parts.

Fortunately there are now practical F3P kits by RCFactory on sale:

https://www.rcgroups.com/forums/showthre...ATILE-CLIK

https://www.rc-factory.eu/letadla/indoor...lite-red-2

The kit price is Euro 73. If you buy it with the full equipment set it costs Euro 155. I have a superlite rc-factory model which I found took longer than an average RCFactory foamie to build, but its not more difficult. I fly it in a local oval at sunrise.  I found I did not need to buy the equipment set, as you can source your own suitable servos, motor, prop etc. In Australia Micronwings is a good source of small rc parts, eg 3gm servos:
https://micronwings.com/product/servo-em...m-digital/

Note you can fly indoor models outside, if you get up early enough when conditions are still calm, and you can fly them in a backyard or anywhere.

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  Preventing lipo fires

Posted by: greggold
29-09-2023, 01:13 PM
Forum: General
- Replies (2)

I do not have an outside garage to store and charge my lipos, the hobby workspace is inside our house.
I recently found a useful item at Bunnings, its a Craftright steel toolbox (159mmx137mmx385mm) for $15 that has a clip to keep the lid shut, and can hold 6 or more lipos. I now have 4 of the craftright boxes, 2 other metal boxes that look similar, and a medium Batbox which is a fairly pricey item. I divide my collection of 2S and 3S lipos between the 7 boxes, and I also place the removable lipo battery from the electric lawnmower in a box.

The storage is just one aspect of preventing a lipo fire, I am sure most points are well known but this article covers them fairly well.
https://dronebotworkshop.com/lipo-safety/

I generally charge 12 lipos for a flying session, so I use 3 dual chargers (mainly ToolkitRC M6D, that have no AC connection and run off a separate power supply, and are considerably cheaper than AC power models). I choose the ToolkitRC after trying several other brands over a long period. Thus 6 lipos are charged simultaneously, and as the article recommends I charge at 1C. So I hang around the workroom for 2 hours while the charging takes place. I always check individual cell voltages several times during balance charging, and the IR at least once. 

I keep welders gloves and a fire blanket handy, in the hope I could wrap up an igniting lipo and throw it into the yard in time. I have a fire extinguisher ready for other items that may have caught fire. And the room has a smoke detector. I do not pretend these measures ensure perfect safety, the aim is just to make it as safe as possible.

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  Using 2 aileron servos with a elrs rx that has 5 sets of pwm pins

Posted by: greggold
19-09-2023, 02:47 PM
Forum: General
- No Replies

The betafpv rx has 5 sets of pwm pins.
I have not used the betafpv rx with 2 aileron channels (I used a y-lead). However Florian is using this rx on his superextra with 2 ailerons plugged into the rx.

The number of sets of pwm pins is not the number of elrs channels, I set the number of channels to 8. When I run the elrs lua, I get packet rate 100 Hz full, telem ratio 1:32, switch mode 8ch, model match off. 

In the mixer you leave ch 5 empty, and set one aileron to ch 6.  This ch6 aileron then plugs into the 5th set of pins.

As a general rule, leave ch 5 empty in the mixer. It is the elrs arming channel, and arming is best managed with the same switch you use for throttle cut/throttle armed, using a special function entry.

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  1. Parramatta Radio Control Aircraft Club