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Member postings for Peter Christy

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

Thread: Silencer Gaskets
05/07/2020 22:57:10

Another +1 for 5 min epoxy.

I was taught this trick many years ago, and I've never had a silencer come loose or leak since adopting it! I do use a drop of threadlock on the bolts, but that's just to stop the bolts coming loose, not the silencer!

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Pete

Thread: 1965!
05/07/2020 08:46:52
Posted by Bob Cotsford on 04/07/2020 15:02:07:

Be warned, there was something odd about Horizon's PWM modulation as mine wouldn't work with anything but Horizon receivers.

There was indeed! Everyone else used a synchronising pulse that was longer than the longest channel pulse to keep the receiver in sync with the transmitter.

Horizon chose to use a sync pulse "shorter than the shortest", rather than "longer than the longest". This gave it a higher frame rate than other systems, but at the cost of considerable incompatibility. Receivers were not interchangeable with other brands, but also there were issues with servo incompatibility as well. (Similar to the present issue of using "analogue" servos with a high frame rate system).

It was also more difficult to detect the sync pulse - typically only 0.5mS, compared to a conventional 6 - 10mS. The final straw came when FM systems arrived, along with the requirement to operate at 10KHz channel spacing, rather than the previous 25KHz. It was difficult to fit such a short synchronising pulse into the required bandwidth!

It was an interesting attempt to do something a bit different, and worked OK, but in the end the relative simplicity of conventional systems won out.

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Pete

Thread: Aurora 9x
01/07/2020 12:51:39
Posted by Steve J on 01/07/2020 11:41:55:

It will be a shame if Hitec have completely pulled out of the transmitter market. We seem to have lost quite a few transmitter manufacturers over the last few years.

But a drop in the ocean to the number we lost in the latter part of the 20th century!

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Pete

30/06/2020 22:22:36
Posted by Glenn Stevenson on 30/06/2020 19:13:20:

Not sure about the Jumper radio, prefer a name that Ive heard of.

Its a shame that the options are only expensive (Jeti etc), unreliable, cheap chinese or Futaba.

Hitec could have made a device that beat them all.

Glenn

I've never had a Futaba set, though I've had lots of JR. I've also been using FrSky for around 8 years now. Despite being a) cheap and b) Chinese, it has so far proven to be every bit as reliable as my JR equipment but at a much lower cost!

I can't comment on Jumper, Jeti or HiTec as I've never owned one, but I can say that being cheap and Chinese does not necessarily equate to being unreliable! Indeed, my experience is quite the reverse!

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Pete

Thread: Dynam hurricane
28/06/2020 09:50:26

My Waco:

Note the droop in the starboard upper wing, and the protruding mainspar! And that was before I flew it!

I managed to straighten the fin and rudder (mostly) by ironing, but the twist has crept back in the rudder. The elevators are also slightly twisted.

The main spar on the upper wing completely came adrift on the second flight, when I landed a little heavier than intended. Not a really heavy landing, and no other damage. But a main spar dropping out?!?

To get it back in, I will have to remove the whole upper wing and straighten it, somehow. And lord knows what glue to use - epoxy? The spar seems to be aluminium.

This kit is total junk!

--

Pete

Thread: How Windy is Too Windy
26/06/2020 11:20:17

When I see the seagulls walking, I give up and go home! wink

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Pete

Thread: Sanwa old 35mhz servos
22/06/2020 09:00:31

Nothing wrong with using old gear, it doesn't usually deteriorate if stored in dry conditions.

I would recommend replacing all the battery packs, however. These can and will lose capacity through lack of use. Also check carefully for "black wire" corrosion, which despite its name, happens on the negative lead regardless of colour! Have a good look at the transmitter negative lead and connections especially, as these are generally not so visible or accessible as the receiver ones. Carefully take the back off the tranny and have a good look!

If all looks good, the only other thing to do is to move all the sticks and servos *slowly* from one end to the other. This will show up any rough spots on the pots left by lack of use. Usually a few good wiggles will clear them, but check by moving them slowly.

Finally, a standard aerial down range check, and if it passes, you are good to go!

Have fun!

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Pete

Thread: 4.8v Futaba Servos
21/06/2020 10:54:22

I've been using Spektrum receivers since they first came out. Although I've now moved away from Spektrum, I still have a few models with Spektrum receivers on board, including one large, petrol powered scale helicopter.

I have never run them on anything other than 4-cells, AA on smaller models and sub-Cs on larger ones (as recommended by Frank S above). This is mainly due to having a LOT of JR servos that don't like higher voltages.

I have yet to experience a "brown-out".

I do use good quality switch harnesses.

I have, however, both experienced and witnessed far more issues with regulators and battery backers than I have ever seen or heard of from running Spektrum on 4-cell packs.

A *well-maintained* 4-cell pack and a decent switch harness (NOT one that incorporates a charge socket in the switch!) will be perfectly fine, in my experience.

The more you insert between the battery and the receiver, the more there is to go wrong! Keep It Simple!

Bert: Is your dad Barry, who used to fly up at Little Haldon in the 60's?

--

Pete

Thread: FrSky FLVSS Smart Port LiPo Voltage Sensor
20/06/2020 14:57:44

No!

The V8 series receivers do not support telemetry.

You need either a "D" or "X" series receiver to provide telemetry. Either of these will work with the Taranis, but the "D" series - like the "V" series - is obsolescent. I would recommend an "X" series receiver.

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Pete

Thread: PNP Repair
18/06/2020 09:41:45

Re: Stabilit Express - This is certainly excellent glue, but expensive and not easy to find nowadays. I came across it as the recommended glue for building the gearboxes on early Schluter helicopters. It was also recommended for fitting the wooden parts into the fibre-glass fuselages.

I've recently been re-building some old Schluters, and for the gearboxes they now recommend UHU Plus Endfest 300. This is a lot cheaper and more readily available than Stabilit Express.

Endfest 300 is an epoxy glue. Another option might be Uhu Plus Acrylit Express. This is more like Stabilit Express, with one part being powder. From the name, it seems to be some sort of acrylic rather than epoxy, but as all the literature is only in German, French and Italian, I can't be sure! I can make out that it is recommended for metal, porcelain, acrylic, glass, polystyrene, and polycarbonate - amongst others that I don't recognise!

One or the other ought to work!

--

Pete

Thread: Horus RTC battery
17/06/2020 22:37:47

GPS signals contain a very high accuracy time signal, so maybe the "Adjust RTC" option allows it to update automatically from a known source. The standard clocks do drift a bit.

A PC can also do this using a timing signal from the internet, so this would make sense. However, I don't have a GPS unit so I can't confirm.

Your mixed results maybe to poor GPS reception indoors? You probably need a good signal for it to work properly.

--

Pete

17/06/2020 17:19:32

Thanks for that, Geoff! It looks a bit fiddly, so an "idiot's guide" is very useful!

I do wonder why manufacturers make consumable items so hard to change! I recently did a JR-388 which doesn't even use a battery holder - it uses a battery with tags welded to it, which is almost impossible to find! I ended up soldering some thick-ish solid copper wire straight to the battery. Worked like a charm, but again, dead fiddly to fit!

And don't even ask about the CNC milling machine where we had to dismantle most of the control unit to get at the board with the RTC battery on it.....!

angry

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Pete

Thread: FrSky Neuron ESC
17/06/2020 12:02:57

Thanks Bob, that's a useful link!

He is mostly talking about quad setups, which I believe are generally low-inertia, high rpm set-ups. My requirement is almost exactly the opposite - very high inertia, low rpm! Nonetheless, some of the descriptions he gives are useful!

I get the impression that not a lot of people are attempting what I'm doing, so perhaps I'm pioneering a bit here! Most of the guidance on electric flight conversions applies to either fixed-wing, or high performance helicopters - both of which are pretty well understood.

Working on vintage stuff (typical headspeeds around 1000 rpm, maybe less) is a whole different ball-game. For example, my Schluter Cobra and DS-22 both use motors for which the recommended speed controller is 80A. However, most of the time they seem to be drawing around 20A on 6S. The little Lark flies on 4S and draws around 17A.

Unlike fixed wing, you can't adjust the "prop size" or gearing. You have to choose the motor to match the application. This is where the Neuron comes in very handy, as all the telemetry gives you a good idea as to how close a match you have achieved.

Actually, on the Lark, I did manage to adjust the gearing slightly, as it has a belt drive for the first stage reduction. The Schluters have an oil filled gearbox, and you cannot vary the ratios.

Just to give you an idea of what I'm playing with:

 
 
I need to make a new rotor shaft for the Schluter! There is a lot of play in the "Jesus bolt" that connects it to the gearbox, and the constant knocking is likely to shear the bolt, hence my caution for the moment!
 
--
Pete
 

Edited By Peter Christy on 17/06/2020 12:10:49

17/06/2020 10:37:27
Posted by Mike Blandford on 14/06/2020 23:37:20:

Some settings to check, I had some interesting results with a 600 kV motor and 3S/4S cells:

What is the current limit?

Increase the "ramp up power", I had to do this to get 3 cells to give full power..

Turn rpm power protection off. This is significant more for low kV motors. The Neuron can decide the motor is too slow (e.g. stalled) so limit the current.

BTW, I reckon the full size pup flew on 40 to 50 watts per pound!

Mike

Edited By Mike Blandford on 14/06/2020 23:38:13

Mike: What is your definition of "low kV"?

I see you mention 600kV. I'm using a 580kV on 6S in a vintage heli ( **LINK**

and I have been struggling to get the desired rpm (Neuron 80). When it stops raining (!), I intend to try your tips, but for future reference I would be interested to know your definition of "low kV".

Similarly the "ramp up power setting". I'm flying a modified Micro-Mold Lark on 4S using a 1300kV motor, and a Neuron 40S. Although its flying nicely, its not as spritely as I might have expected.

These parameters are poorly explained in the manual, and a bit of insight into what they actually do would be much appreciated!

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Pete

Thread: Leisure or standard car battery for charging lipo's
16/06/2020 18:29:17

Posted by Dickw on 16/06/2020 17:32:19:

I used to use Leisure batteries but got fed up of repalcing them every couple of years.

Interesting! I bought a leisure battery some years ago for this very purpose. It cost a lot more than the equivalent car battery, and didn't last at all well. Thinking I was just unlucky with a one-off, I bought another - which lasted a similarly short length of time!

Nowadays, when I replace a car battery (I tend to keep my cars a long time!), I keep the old one and use it for LiPo charging at the field. Even a knackered car battery usually has enough for a days sport flying!

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Pete

Thread: The Gov't, CAA, BMFA & UAV legislation thread
15/06/2020 09:44:26
Posted by Steve J on 15/06/2020 09:18:30:
The primary driver is enabling commercial unmanned aircraft operations.

Hence my comment about making sure your site is on NOTAMs, etc.

That ought to ensure that commercial drones do not pass through your airspace.

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Pete

Thread: Diesel vs glow on a .5cc engine
15/06/2020 08:29:41

For Cox .049s, special pistons and liners are (intermittently!) available that do away with the sub-piston induction. They also add an extra transfer port (as per the TeeDee) to restore most of the lost power.

These run well with silencers, though I haven't tried to throttle one - yet! wink

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Pete

Thread: FrSky Neuron ESC
15/06/2020 08:26:05

Some good tips there, Mike! Thanks!

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Pete

14/06/2020 22:12:01

Geoff,

You can calibrate it against your transmitter the same as most other escs.

Set Tx to full throttle (probably best remove the prop first, just in case!), power up the esc. Wait for all the beeps to stop. Shut the throttle. Wait for all the beeps to stop. Disconnect and reconnect the power, and it should now be matched to your Tx.

When you connect it to BLheli32 it should read whatever it is now calibrated to.

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Pete

Thread: The Gov't, CAA, BMFA & UAV legislation thread
14/06/2020 18:10:31

The BBC are reporting that Sussex police paid out £55,000, but that they are also facing a claim of £145,000 for legal expenses!

**LINK**

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Pete

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