Bravedan

Decided to pull this out rather than include in another thread.

Most Chargers have a LiPo Balance feature. Many "hide" this so when you choose LiPo it shows "Charge" and only if you go on down the menu tree does it then show "Balance". This catches a few people out, and a good few have thought that "Charge" does balancing (not on this firmware!) or that "Balance" means only balance, not do a balanced charge as it does..

Even with that out the way, it has to be said that Chargers generally SUCK at balancing well while charging a pack!

I have for some years been using a "Two Meter" to occasionally better balance packs, and this does a much better job than the Charger.

However, recently I have obtained a device from ISDT called the "BattGO" (Code BG-8S). This is both faster and more accurate. It also has a super clear display, AND it can be used to show the signal PPM/PWM/S BUS with receivers to trouble shoot those areas too.

http://www.isdt.co/bg-8s.html

Well worth considering.  Beginning to be widely sold, but mine came from Banggood.

No simple one line answer!

While the obvious safety advice is that if its swollen, its finished, a LiPo is generally OK if:-

1. When charged each cell sits between 4.17v and 4.21v such that the max difference between highest and lowest passes a balance checker test.
2. The internal resistance of the pack allows the current needed to be drawn for a normal calculated duration.  Bench test run.

Minor swelling of the outer cells or cell packaging in the stack is a sign that the pack has been stressed. The swelling might be serious in the sense that the pack paste structure has been affected, or minor in the sense that the sealed pack has been expanded by heated air, often during an over use run at high drain current, which may or may not still be trapped, keeping the swollen shape.

If you can detect that ALL the cells are no longer normal DITCH THE PACK IMMEDIATELY.

Put a slightly swollen pack in the freezer for 20 mins, and if the swelling disappears (and lots will) the problem is not necessarily fatal.

Treat all swollen packs with suspicion, charge them outdoors away from anything flammable, store them outside the main house in a LiPo bag, and you may well get years more use.

I have somewhat swollen packs that have been that way for five YEARS further use to no noticeable effect (notably Tipple). I have packs that have not swollen yet have without being stressed suffered a chemical composition change causing excessive internal resistance and a load giving duration in seconds, though sit happily at 4.19-4.20 volts per cell (Gens-Ace..........YUK!!).

Duration and power have no direct relationship to minor swelling.

And someone stupid enough to buy it may well be stupid enough to fire it up.

http://www.ebay.co.uk/itm/model-engine-test-stand-/362087810400?hash=item544e1d8560:g:YE4AAOSwOsBZnvy1

On 01/09/2017 at 10:36 PM, Pilot Ben said:

Are there any differences in setup/running between 2 and 4 stroke?

B

Basically, no. There are four stroke plugs which cope better with the long delay between firings, but the carb still has the usual adjustments so the inveterate fiddlers can still twiddle and cock it up!

 4 St tend to prefer (or should that be tolerate! ) lower nitro levels than 2 St . I tend to run all my 2St on 25% but 4 St on 10%. These days the manufacturers recommendations/instructions are much better at advising than they were so I suggest you have a think, choose a few right sized engines in your price range, go read the instructions from the manufacturers website, and that will give you a decent grounding and help you decide.  When bought follow their advice initially regardless of others (inc me!) and carry a sharp knife in case anyone wants to fiddle!!

If you don't have a engine running in/test stand you can borrow mine on its workmate. PM when and if required.

As an addendum, IF you decide to buy 2St (and that is YOUR decision, I'm not necc advising that route!) the trick with them is to buy a little bigger than needed so they fly at less revs.

My Panic with SC91 and a large dia low pitch prop is very quiet in flight as it just does not need to use revs, and that is where the normal noise test process fails, as it is never ever run as a noise test states.  Its even quiet when prop hanging. The down side to this method is that the power available from a large prop is sufficient at fully safe idle to fly the plane and landing requires a little thought, namely setting up Idle Down to reduce idle thrust (you don't set this low for normal flight as its more likely to dead stick the engine in extreme moves when throttle suddenly cut). There still has to be prop to ground clearance though, esp for tricycle gear planes!!

Having any engine "scream" is never going to meet noise requirements, neither is it the best way to get flexibility and good throttle response.  Reducing the delay in throttle response with a larger dia but low pitch prop enables fast changes in airflow from the prop over more of the flying surfaces for better control at low airspeeds (such as landing).

Many years ago now I had an 8cc rear disc crankcase induction 2 St engine (early Schneurle ported) that developed 1.25hp at 14, 500 rpm, the prop was more like a toothpick and it took near half a lap of the pylon course after a horrendously wobbly near stall hand launch to get up "on the prop" when it instantly became a warp drive machine, literally a blur, but the day for that engine in our current noise climate has LONG GONE!!

Love the fact that the TJD website shows a 91 2st and a 91 4st on the Tucano page like they are equivalent power for it. Helpful - NOT.

In principle, and these are sweeping generalisations:-

Petrol - Cheaper to run, more difficult to install, more difficult to keep noise down to limits (std exhausts usually rubbish!). Was trendy a year plus ago.

Methanol - Considerably dearer to run, more awkward starting and tuning requirements. Less likely to suffer "heat in cowl" issues. Known type to you so used to handling

There are SO many "but if's" though, for example, why install an engine that will run for 30 minutes plus on a tank if you never fly more than 10 without needing a break? How many hours per year will you fly it to make the running cost differences truly significant?  Are you going to be happy with mixing oil to petrol in correct measures, etc. Are you going to carry both fuel types back and fore?

Lasers are excellent. I don't like model 4 strokes, don't see the point in throwing away half the power strokes for an allegedly "better noise", but my Laser is good enough to ALMOST make me change my mind and they largely negate the awkward tuning comment above!!   However, they are certainly not the most powerful engine for their capacity.

LOT of rubbish about all types of engine on Internet and in clubs, esp from the brigade who won't leave the damn needle alone for five minutes or allow the engine to come anywhere near operating temp before tweaking it expecting it to idle slowly forever and respond instantly to snap openings of throttle.

Also lots of rubbish spoken re: taildragger or tricycle. Adopt the right set up, CG and technique and there's little or no difference in result. Should be OK at the field as it'll be light for its wing area.

Finally, and continuing the Devil's Advocate process to the bitter end, what on earth is "real" about a 4 stroke model engine, they do not actually sound remotely like a real warbird engine, esp in the case of the TURBOPROP Tucano.................. 

Got to go, there's some Gliderists over there to annoy..............................

On 30/08/2017 at 10:06 PM, Pilot Ben said:

I also wondered about cowl filling to avoid the cowl becoming an oven? Any details about this please?

Hot air expands, the exit needs to be significantly bigger than the inlet (people constantly get that wrong!). Airflow needs to be routed over and in line with fins.

It's not rocket science, you'll be fine!

Shane, It made sense before, but:-

1. I question the validity of the "adjust the mixture to synchronise twins" advice you found out there, not your interpretation of it.

2. I don't think it's necessary to have automatic throttle compensation in the same way I do not mix elevator to flap or mix up a knife edge mix.

3. I think the "Twin Sync" is possibly an application seeking a need rather than the other way round, in the same way that people fit in flight adjustable mixture to RC Helicopters, which in effect is either admitting they can't set an engine up for toffee or that fiddling is more important than flying. 

However, if I was up for a scale twin I'd be going electric with a sound system, a result as "real" as is possible and considerably more issue free in use. 

I hope to be able to see the result if you go for it, Good Luck, and keep reporting here please!

Differential thrust management does not "detune" an engine! You do not tune an engine with throttle.

Keep in mind than most manufacturer recommendations are based on American site standards and NOT draggy short grass strips (no insult to the now good grass cutter intended!)

Moi, Brutal?   

Pretty sure engine power sport twins have flown Fickleshole, memory says Oily (Peter) or Roger?  Dunno about twins at scale model weight though in the available space, every TO and landing would need to be perfect.

Noise very likely an issue, suspect much more of a problem with petrol than four stroke glow.

A while back i did a couple of electric twins (both still extant) and used "throttle" to "rudder" mixing for differential thrust, both with stick to act as rudder and trim to synchronise throttle. This only used two channels and was effective, so effective apart from the sync that I could fly smooth "bomber" circuits on "rudder" and "throttle" using only the LH stick (Mode 2). With OpenTX virtually anything is possible, and it keeps it simple. Your solution is tech heavy and the more you have, the more there is to not work as expected under stress, fail or not be set right in the first place!

Two Channels, one feeds throttle servo 1 as master, slave to throttle servo 2, the other channel fed to throttle servo 2 as master, slave to throttle servo 1.

Yours is nice idea but "KISS" and some attentive piloting is always best.................................

That is a very suitable plane for quite a few members here.

Have to ask though, WHO have you got locked in the freezer?

Hi Terry,

Good to see you back on't forum!

I'm probably the closest to you (if you have not moved!) and am up to date on values etc. I'm back from Hols so around this week, and even if not passing your road to/from field could call at a time the mad mile is not clogged.  I'll PM my phone numbers or PM me here.

BTW, I have not flown the "Edge" so far this year but it's still active!!

Dave

The VTOL Eflite Convergence has a magnet attached canopy and that was designed for FPV. (cynically that's maybe why some are falling out of the sky cos it would NOT be the pilots or Spektrum, would it!!)

However, think about Quads, they have LOTS of powerful magnets in the motors hurtling round and round (I have just completed a 250 that has 1.7kg of thrust PER MOTOR, getting close to 7kG pull, so imagine the magnetic power!!!!!), and the ESCs generate all sorts of RF clutter, often all jammed up together. The trend is to smaller quads with bigger motors and small high pitch or multi blade props on short arms, so motors are increasingly getting very very close to the FC, etc.

ALSO, there's another trend to have the FC, OSD and PDB all in the one board ( sometimes the ESCs as well, or in a 4 in 1 board stacked on top ), so to access the OSD the camera feeds the VTX via the FC board.

Its much more necessary to filter the power feeds to Camera and VTX or at least check they are filtered if separate items, something most FC (but not all) do reasonably well as long as you take the feeds from the right place as designated. (Yes, I have seen people hook them off the ESC supply line!)

HTH,

Dave

On 01/08/2017 at 10:32 PM, orange_rc_pilot said:

would mounting a receiver antenna next to a magnet have bad effects?

Finally, would mounting a flight controller (I'll be using the KK2.1 hard case) near the magnets mess with the accelerometer?

Sevan.

The VTX Antenna needs to be as far from ANY metalwork or carbon plate frames, etc as you can practically get, if poss so it is line of sight to the VRX antenna.

Unlikely to affect accelerometer, Magnetometer is another matter!!!

https://www.bmfa.org/News/News-Page/ArticleID/2475/Government-Publishes-Consultation-on-the-Safe-Use-of-Drones-in-the-UK

http://www.bbc.co.uk/news/uk-40697682

That drone is from the photos a DJI Inspire, and costs roughly £3000 min to put in the air, and needs a lot of power to lift its 3 plus kg weight. Beginner material? Should a beginner be ABLE to buy one AT ALL?? This is the drone equivalent of a raw beginner fixed wing pilot with a 100cc 1/3 scale petrol plane. Or a learner driver with a suoercar driving it solo.

Registration would have made no difference.

An Online course would have made no difference (The owner had rec'd hands on training which it seems was not complete, yet went his own way taking someone who sadly needed a grounding in common sense possibly even more).

As EASA has long stated, and which has not been counter stated anywhere AFAIK within the UK or Euro zone, registration changes are planned to apply to ALL unmanned aircraft (within whatever weight etc bands they finally end up with, they seem to just be copying Canada's "blind man in a coal cellar" approach since they can't copy the USA as its been legally squashed!).

Any changes are therefore heading towards ALL model flyers despite what the press choose to highlight.

( why I posted in members, general)

................... differing designs of prop make little difference............................

How it flew with the "latest thing"...................

and this is what it SHOULD go like and did after the props were swapped back...........................

And the REEEEELLLLLY BAD props?  Flying Fish Tri 5041 blades from www.ideal-prop.com

And the good blades?  DAL Tri 5040 V2 from a variety of sellers including UK sources like hobbyrc

Quick Mini-Review

Been around for a while now, has the VTOL able Convergence, so there's quite a few reviews, unboxings (and WHAT a box, it's immense, so if you need to smuggle it in its NOT for you!!) and first flights on YouTube.

Here's my extensive review...................... "It does what they claim".

Good Review, Eh? 

It's not the absolute easiest Delta to fly in plane mode, its not the absolute easiest Tricopter to fly, but its perfectly adequate at both. IMO and from my background I went straight to acro non self-levelling and feel that self levelling mode is only useful to finally land after entering hover, and probably more useful with FPV than when LOS. You CAN fly in plane mode but it requires S....P...A...C...E !!!  However, I connected it up, took it into my garden, and in a swirling breeze was instantly flying eights in Tri mode, it gives that confidence.

A few have come unstuck with it while transitioning back to hover from what has proved to be too high a forward speed, it seems the only area the flight controller gets confused in and if (when?) you do you WILL end up in a high alpha posture with reduced control!  The only practical way to get out of this is to switch back to flight, then back to hover if you are now slow enough and have not stuffed it in. It'd read of this trait, so deliberately tried it out, its not as scary as many make out, but then I'm used to wrestling 3D planes at or beyond the stall and quad flying.

Why did I buy it?  Mostly because it is designed to accept FPV gear, which change will happen shortly after the quad build on the board now is done.  T/O and landing are if anything the highest risk areas with a conventional plane flying FPV and this can only help................can't it??  

OK lets treat this as if if were not a wind up...................as some may get confused..........................and putting it in print without clarity is not helping our case for being responsible people fully capable of being safe when taking part in our sport.

Cost of Rx battery?     Less than £8

https://www.vapextech.co.uk/batteries/radio-control/receiver-packs/4-8v-battery-pack-48v-2600mah-nimh-flat-vapextech-rx/

https://www.vapextech.co.uk/batteries/radio-control/receiver-packs/4-8v-battery-pack-48v-2500mah-nimh-instance-flat-vapextech-rx/

https://www.vapextech.co.uk/batteries/radio-control/receiver-packs/?p=2

etc, etc...........

Versus:-

Cost of plane, gear, insurance claims, hospital bill, time attending court, loss of flying field, etc, etc, etc?

Good luck convincing a court you were complying with :-

When they learn you avoided spending £8 to be safe and so avoid someone being injured or worse.

A NORMAL NIMH battery will steadily start to lose its charge even if not connected anywhere in a few days, unlike a LiPo or LiFe. It is therefore risky not to top up charge before use if several days have elapsed.

The "ENELOOP" and "INSTANT" types were introduced to limit that loss, though TBH I prefer the normal type as a lot of the low discharge NIMH available exhibit other flaws esp the ability to be easily over charged and damaged if repeat charged "to be sure they are OK", as some people used to std NIMH do.

Most chargers are simply sensing the start of a negative dip in cell voltage on charge completion, and some low discharge cells fail to trigger this crude shutdown process fast enough to avoid damage when "topped up" more than once in quick succession.

NIMH batteries of all types do not have the "memory" that afflicted the (now banned from sale) NICAD so cycling is not necc nor is discharge to low or min voltage any particular advantage. (Cadmium is a heavy metal, dangerous in the environment, and must be carefully disposed of)

I tend to use Vapextech products (a local mail purchase firm!)

I charge over 100 normal NIMH packs every week, some of which are over ten years old !!!!

Following on, are you aware of "black wire" syndrome? This particularly but not exclusively affects low current circuits subject to intermittent use like Tx and Rx pack wiring.   It is not a problem exclusive to the black insulated wire (as you will find stated by "experts" on't Internet!) , though can be first evident there through leakage to earth in circuits.

It is blackening and eventually crumbling away of the copper conductor, with increasing resistance and loss of current carrying ability.

Unfortunately it is usually hidden out of sight and mind behind wire insulation/sleeving/casing and has to be looked for. It is usually THIS which limits pack life and has caused over the years lots of crashes!  Its another reason I do not like the Instant type, as with many people they get left for months and are then used with no charge and no inspection!

ANY wiring on RC gear can be affected, cell pack, switch harness, etc. I have had four cell 3700mAh NIMH car packs with shrink wrapped and plastic ends fall apart internally and the wire rot off the out of sight inside the pack battery connection. Simple voltage checks do not find this!

The pack has usually been fine again once the wiring was replaced, BUT if that had been an in use plane pack...................!!!  Hence the general advice to regularly inspect carefully and replace unless frequently used and carefully checked.

Ben, having 52 power is not necc defeating the object or a waste, subject to its handling.  The greater power/torque allows (you infer forces, its a question of perspective!) lower revs sure, but that is a benefit and keeps the noise down, particularly prop generated noise, and with a lower than usual pitch prop gives scope for instant blips of power to put prop wash over the surfaces for control when the airframe has no airspeed to give it due over ambitious 3D or just getting it too slow!

My first RC plane was a third or fourth hand Super Sixty, (60" span high wing cabin) the sort of "classic" airframe that often had a tiny diesel up front, or at most a low power 19.  I had a 60.  It didn't out power the thing, it didn't add too much weight, but it gave really good versatility and the instant power needed to get out of jail when that long one wheel touch and go didn't QUITE work out.

With regard fuel consumption, the not that much larger 52 will be running under less strain and so lower than expected fuel burn, and may even be more economical than the harder working 46.

For the record, SC, ASP and Magnum engines are all made in the same factory, British Leyland obviously exported their badge engineering expertise. I have used SC for planes since at the stage I was buying they were easier to get.

You'd need to check but 46's and 52/53's usually use the same crankshaft casting so weight is not really much of a factor.

NO experience of any of the four strokes as I try to avoid them (except Lasers), as I really don't see the point in adding weight, more wear out parts, and throwing away half the power strokes for a "nicer" noise. .

For heli's I use Thunder Tiger Redline (53's mostly), superb engine, but no experience of the plane units.

ENYA is another excellent under-rated make. (Steve Webb Models)

No such things as a nice model 4 stroke.................

None in that specific thread are exclusively mine, but I have teamed up with "Rickp" on a few.   In the past I have done a number of 3D models and skins for Flight Sim and three figures numbers for Train Sim.

The "Spin Delta" in that thread is a design of mine, and I sent the details and graphics photos to Rick, and then "tuned" the model close to "real".

Some of the later issued models by Rick use the Phoenix package input method, NOT a zip file.

(BTW, there's some of my work in that thread, tuning and complete models with Rick)

With regard the "rearward CG" of the Cougar, though I had no input to that one, it's a Fun Fly, it's SUPPOSED to have a rearward CG and the worst part about the "real" Cougar is getting the gear in far enough back to make it work well without just adding weight.