Here is a list of all the postings Peter Beeney has made in our forums. Click on a thread name to jump to the thread.
|Thread: Motor Ident?|
I probably wasn’t that far behind you, I’d already guessed that the unloaded revs were in the 17,000 region; 17,285 to be precise. But that in turn is making me more than a trifle suspicious too. Those current consumption figures do tend to stand out from the crowd a little, 52 amps to drive a 9 x 6 on 3S?? Put that lump in your model and you’d flatten the battery in less than three and half minutes! ….And just how far is 52A out of spec. anyway? Can we now barbecue some sausages on the ESC?
On the face of it, it appears you are getting an approximate 1,200rpm gain for a 22 ampere current flow increase. Based on this, to get to the sort of figures I might want to be looking at I think I might need to be looking for something like a 7 x 2 prop…
Do you by chance have a link to that motor please? I can find the 1,000 and 1,250 ok but not the 1,450. Perhaps it’s gone into hiding, if so is there a reason for this I ask myself?
Carry on dabbling, Roger, it’s all getting nicely interesting…
Edited By Peter Beeney on 05/07/2020 12:15:24
Edited By Peter Beeney on 05/07/2020 12:17:35
Just measure the motor revs without a prop on, Roger, that will give you a reliable datum to base all your other measurements on. I usually do it with a 12V car battery, that’s a good constant voltage supply, the load current is minimal; and for the same reason a fully charged 3S is fine, very little voltage sag.
Should be a ‘must do’ in every case case anyway.
Hope this helps.
Sorry Pat, you beat me to it… must be late…
Edited By Peter Beeney on 04/07/2020 21:42:29
Edited By Peter Beeney on 04/07/2020 21:43:28
|Thread: Prop advice please.....|
Yes indeed, you do have a little predicament, Roger, not really many easy answers here I guess. Changing from i/c to electric is not always that simple by the look of it.
Just a fag packet type of speculation but if you were starting with a bit more leeway here 2 x 2Ah 4S packs in parallel one behind the other in the fuz might have been an option. That in turn might now make it possible to find the right CoG without any additional weight so it might not be that much heaver anyway. Selecting a prop, to me something like a 10 x 7 looks like a likely first candidate for a fictitious 50in span speedster weighing in at something well under 5lb,(hopefully), that should be turning at least in the order of 10,00rpm. Such that a 40 i/c might do. But 11k would be a bit better, though. Such that a OS MAX-35AX might do. The extra watt minutes we have will allow us to bump up the current to around 35 amps and still have just about 5 mins duration down to 30% capacity. Using nominal figures, an 850 kV motor will spin unloaded at 12580rpm, ideally our prop needs to revolve at about 11000rpm to be within our preset limits, slightly faster would be better. So an 850kV 800 watt motor might be choice. 800 watts still gives us a bit of headroom on the max current flow with fully charged batteries.
First setback here maybe a bit of a lack of 850kV’s but a 900 pops up here straightaway which looks to be just about perfect all round for our fag packet…sorry, model. Job done…
But if it were only that simple…….
With the greatest possible respect all round Roger, I have to say I’m a bit suspicious of the 11/6 at 8500rpm though. As usual I may be completely wrong but that seems to me to be now lurking marginally beyond the borderline of a rather marginal place to be in the first instance!
Many thanks in turn for your reply Roger, much appreciated. And at the same time I’d also tend to think that your ability to be able to consistently fly a somewhat underpowered and at the same time rather portly model regularly and safely must be a honest and lasting tribute to your model flying skills too…
Being naturally a bit lazy I’ve always picked up the tacho first, at least I can very nearly understand this particular device! When tinkering with a new electric motor I alway check the unloaded revs first, then bolt on a likely looking prop and check again; then in a trice it’s possible to be able to predict to within a reasonable degree of accuracy as to how it’s going to perform and how close (or not!) I am to arriving at the ideal prop size. Of course an added look at the current flow with a clip on power meter and a temperature check for local hot spots with a contact thermometer is never a waste of time either and makes it all a little more interesting anyway; also it might help to find out how wrong, or perhaps not quite so wrong, my guesstimates were in the first instance. Although a slightly more difficult decision to make before you even begin this caper though, is maybe choosing what size of propeller to use for a particular model and also how fast it has to turn to get the result you want…
Anyway, all best wishes for a future long and unbroken life for your model…
So to try and answer your original question, Roger, is that I at least would consider whilst the 10/6 won’t really do much harm it might not make that much of improvement either. Giving it a spin is perhaps the best way to find out; I might be completely wrong, it has happens more than once or three times; but your static figures do suggest that it won’t be quite as efficient. I’m pretty sure that the mechanical turning power at the prop shaft is just about as close as it can be to equalling the electrical power flowing from the battery using the smaller 9 x 6.
Also your post describing the battery capacity flying time and discharge calculations now makes it all much clearer. That’s much better! I’d had another look a it and it really didn’t add up very well at all (for me). I was beginning to think there must be something seriously wrong with your 9/6 prop!
Having now said all this it seems the model might well have been designed as a pylon racer. If so then it would have been the heavy hammer all the way and then some, no quarter given. Success was going as fast as possible… So with that in mind I now think that you may be flying just outside the border line of some sort of rather ‘unusual’ flight envelope; but you’re obviously very successful with it and it’s exactly what you are wishing to do as well. So all power to your elbow! Or perhaps that that should be stick finger!
Many more happy landings.
From the motor performance figures you’ve quoted it seems (to me, anyway!) that the 9 x 6 is just about the optimum size you can use. It would appear to be turning at about the best possible point on the output curve. Certainly worth a try with the 10/6 but your figures for that are already suggesting a slight reduction in performance. The increased current flow immediately points to a reduced prop speed which you point out anyway, so slightly less forward speed (performance?) and it will also slightly reduce the battery duration too. So slightly less flying time per charge; and to say nothing of the slightly increased heating effect as well. Another point to make here, but again OIMHO, your 5 minute flying time points to a constant 33A discharge with a 3Ah capacity. Or in other words, more or less constant full throttle use. Might just take a bit of careful thought as how you can improve this, a different, i.e. more powerful motor perhaps, or as suggested, 4 cells. Here you would now definitely have to go down in prop size but if by some magical coincidence you found that trying say an 8 x 5 resulted in around a 26A current flow using a 2.2Ah 4 cell the increased performance might well give you the ability to use less full throttle, (max current flow), so even more flying time. So 27 - 28 amps might be a suitable starting point. Some experimentation might be called for…
Although to be quite honest and weighting it all up perhaps the more powerful motor option might really be a better bet. To improve the performance somewhat I’d guess you just need a bit more of the right sort of poke!
Re the prop unloading, I think this must happen to all props anyway. It occurs at S&L; and a bit more going downhill but it’s mostly disappeared when you’re climbing; just when you could do with a little help, maybe.
Please don’t consider this as any sort of criticism, or indeed any form or instruction on how to do it. It’s just interesting stuff and it’s only just the way I think about and consider it all.
I can really understand your motive about flying the model too, I had something of a very vaguely similar experience once, but I’ve not managed to finish the model off yet…
Very good luck with it all…
|Thread: Motor stutters near full throttle|
Does a clue now lie in the fact you have 1350 watts versus 860 watts? It did strike me in the beginning that 25 amps at three quarter throttle on the 13 x 8 prop seemed a bit unusual. Plus the fact that the prop seemed to be the only common link during all your trials and tribulations. I always clock the prop speed with a tacho first anyway, that’s a fairly sure way of seeing what’s going on; for me anyway. And my idle thoughts about a warbird of around 9lbs in weight would be that it would surely appreciate at least 1200 watts of power (or just a little bit more, perhaos...) to fly in that nicely spirited manner that warbird should be flown. Flat out! But that’s only my idea, every one has his own personal choices and ideas. Agreeing with Colin it certainly sounds like the Quantum is a potential contender as a replacement. How would you consider your Spit compares physically with your Acrowot? If more or less the same then a likewise power plant might not be far of the button… I’d have thought that the flying characteristics are perhaps not that much too dissimilar, either…
Good luck with what ever you try.
Edited By Peter Beeney on 14/03/2020 19:58:17
Edited By Peter Beeney on 14/03/2020 19:59:16
|Thread: I have Got This Far Should I Just Fly it|
The short answer then Andrew, is that in my opinion the two BECs will operate perfectly happily which ever way you connect them. This has been done in the past with industrial size kit.
With respect to other points of view; not an instruction on how to do it.
There have always been differing options on this little conundrum , it’s probably always going to be an aeromodelling bone of slight contention…
The Clark Y might also be be a good choice for a Bristol Freighter lookalike. Nice and sedate flying. I can remember as a youngster in the nineteen fifties cycling about 20 miles to an airfield perimeter fence just to watch Bristol Freighters taking off and landing.
Edited By Peter Beeney on 25/02/2020 18:23:24
|Thread: Probable scam?|
I have to say, Denis, with the greatest respect of course, but under this sort of circumstance in the first instance I certainly would not be ringing any number given out by any recorded number. That sounds to me a bit like an invite from a sharply operating spider to a rather gullible fly…. I think I’d prefer to call the card’s helpline, generally an 0800 number open 24 hrs I believe, and then taking it from there. If some fraudulent activity was detected I’m sure I would get a personal call; and if they were genuine they would also have some means of positively identifying themselves as well.
I nearly got caught by a legitimate scam once. I noticed a £15 withdrawal on a current account mini statement and couldn’t remember what it was for. For a while I simply thought it was my memory; it can be a bit suspect these days. But being a bit persistent it turned out I probably hadn’t un-ticked a box when I’d done an Argos or John Lewis transaction and as a consequence had unwitting signed up to a monthly email account giving out information on various ‘Best Buys’ Except there were no emails and I knew noting about it at all. I’d actually paid for 2 months, £30, and the bank’s fraud squad gave me a number to ring and the money was instantly repaid. Something I didn’t really expect so I was quite relieved.
When I Googled the comments about this site there were reams and reams of it. And it was worldwide too! A typical one was an American who said he and his wife had a busy joint current account and he eventually found out, much to his chagrin I guess, that he’d been shelling out 10 dollars a month for years. For nothing! But nobody was breaking any rules. Other than that these people had no intention of ever sending out any informative emails. But the fraud squad knew about this and it was a legitimate company. They’d obviously spotted a loophole that’s never been filled….
But it certainly makes me check the mini statements very carefully from then on… and just like that hungry spider, I’ll do my very best to stay ahead of the game.
I suspect the reason these fraudsters are so persistent is because it is so lucrative; and probably also fairly simple to do too, one version maybe using computer generated sequential calls with an operator responding only when someone bites; this will also catch ex-directory numbers as well - there’s no escape. There was a tv item about this recently, including some of the monetary amounts lost, one to remember was a couple in the West Country taken for a million quid, no other details other than that of course, but that would be a shock to anyone’s bank account, to say the very least. Other amounts ran to tens of thousands.
I had a bell yesterday, the caller saying that my Vista/Master Card bank debit card had been compromised, an unauthorised £600 had been withdrawn from my account and deposited abroad. Press 1 to be connected to your bank. I recognised this as a recorded message but there was a degree of urgency about it which I think could quite possibly deceive a person that is a bit confused to start with anyway. It would certainly appear that quite a number of people do respond to these scams, the total amount lost is phenomenal, £500 million to bank scams alone in the first half of 2018…
With money lending control rules changing yet again, I think to try and and limit fraud to some extent, there is one negative side effect for me anyway. As I don’t own or use a mobile phone I find I can’t get a credit card anymore. I discovered this when recently applying for a popular card; my favourite, as it happens. I did pursue this a bit, eventually I got voice to voice with a lady that did know the rules. She politely but categorically told me that I had to supply a mobile number so they could randomly send me a confirmatory text. I’ve not looked at any others yet, but I suspect they will all eventually have to comply with this. But as I’m probably only a fraction of a percent of the population now anyway a workaround solution is unlikely to be coming down the line anytime soon…
Ah well, such is life… I treat every unsolicited email and phone call as fake now until proven otherwise these days…
At the beginning of February I received what at first glance looked like a genuine email from PayPal Customer Care; this stated they needed to confirm the information I’d given them and until I’d done so my account would be severely restricted. There were two links within the email to click on, ‘My Account - PayPal’ and ‘Update information now’.
Nowadays I’m very cautious about any such emails so I just left it for a while and on having a second look look it soon started to fall apart, for instance the senders email address - firstname.lastname@example.org - appears to be a work of fiction and the Customer Care address given - 214 Teignmouth Road Torquay TQ1 4 RX - appears to be an empty residential property!
I use PayPal whenever possible but I don’t make that many online payments anyway. I sent it to Spoof@PayPal but I’ve never had a reply. However, I have just made a donation, the first use since it came and that went through as normal so the account is definitely not restricted….
I’ve personally never had any issues with PayPal in the time I’ve been a user; but another beneficial ‘Rule of Unexpected Consequences’ might arise from this; in future I will be examining any ‘unusually unexpected’ such emails first under a very powerful microscope indeed!! It can work both ways…
To echo Peter C above - you all take care out there……
|Thread: Have I enough power?|
Exactly so. Ray, I’ve always thought along the same lines; although I’m probably even more basic. I start with the tacho and measure the unloaded kV first to make it is what it says on the tin, generally very close but definitely not always the case.
Then I can base everything else on that, relating the prop speed to the unloaded speed I can guess within reason what the current flow will be and also of course very importantly how the model will fly; that’s in conjunction to the already known wing loading, of course.
Then check for any hotspots with a thermometer and verify my current flow guess with a clip on power meter; and then if necessary some juggling with prop sizes when it’s in the air.
And as you say, perhaps not every one’s cup of tea, but then I’ve generally preferred coffee anyway…
|Thread: battery c rating|
Again I shall have to gently agree to disagree with you, for a start I’m not sure that I ever mentioned the C rating as being a motor killer anyway. Maybe rather the opposite, perhaps. I was simply considering choosing the right motor/battery/prop aspect of the discussion. In my view the battery C rating is only a peripheral of this, just needs to be pondered over somewhat whenever a constant high current supply becomes an issue.
As it so happens, sixty plus years ago I was starting to get involved with amongst many other things battery installations such that the C ratings had to be big enough to maintain the voltage between some quite narrow limits under heavy current supply conditions. Usually this lump was an original spec. and well up to the job of course, but occasionally there was an emergency breakdown to fix. In those days you were basically on your own so then you had to do a quick calculation; this simply consisted of wanging in a backup that was definitely big enough for all eventualities and then some to spare, too. However, along the way I did at least begin to get a little bit of the hang of battery speak…….
Very unlikely to be doing any experimenting, either; did all that a while back. Feet up and just read the newspaper nowadays.
The spiders have all died already….. of old age!
Thanks for your reply, but I think that there’s really very little I can add to all this now, other than that I do tend to take a bit of a different slant on the subject. Been tinkering with it for a fair time now, and it’s always worked for me, at least up till today anyhow. Like a voltage going down a wire I always take the line of least resistance; or just lazy, I guess; and I also have to be careful when overdoing the thinking bit, (also very easy for me!), like a resistor suffering from a serious overdose of amps the old brain can get a bit overheated… and well flummoxed into the bargain, too…
Right, now off to brush the cobwebs out of the battery charger…….
Maybe we might have to agree to slightly disagree on this subject, although I’m not even sure now what it is we are actually agreeing/disagreeing about any more…
One point on the little anomaly about burning the motor by using a higher C rated battery, I don’t think this is ever going to be an issue. I’d have thought that at that stage the original battery/motor/prop combo performance was so abysmal that no one would want to fly it anyway. Although having said that I’ve long since not been at all surprised by just about anything that aeromodellers can do!
I’ve long used my own procedures for arriving at the best size of prop to use, and it certainly doesn’t involve clamping the prop stationary and applying full power. Although this does rather make the point fairly succinctly that you can’t always get a firm handle on the speed and power of the prop by reading the battery output on the wattmeter…
On reflection I’ve never seen a burnt motor and I don’t know anyone that has. I did read once about a motor that burnt a coil but that was thought to be an internal short. A few smoking and worse ESCs in the past but electric knowledge, experience and quality of the kit is increasing all the time. In the main I suspect that many electric flyers now spend many hassle free hours these days doing just that without too many problems to overcome!
For our purpose it’s most likely negligible in a good motor, Don, it’s all in the design and quality. There must also be a reactive component too, but we ignore that as well.
Exactly so. Quite agree.
Again with the greatest respect,but there’s just one little point of interest relating to your post, I think the whole chunk of “watts” that you read on your watt meter is actually measuring the produced heat. The mechanical turning action of the motor is the result of a deflecting action between two magnetic fields. All the heat is generated by the current flowing though the resistance of the conductor, no heat is created by the action between the electrically created magnetic field and the permanent magnet.
|Thread: Max Thrust Riot - Upgrades|
Many thanks for your answer above.
I have to admit I’m still still a little puzzled by some of the information here, but then I’m easily confused anyway. I’ve thought for a long time that we have many and diverse views, as someone once said, ask 4 different modellers the same question and you’ll get 5 different answers; and quite likely it’s me that’s the foolish fellow going in two different directions to once… But I suspect it might well be much the same result in other activities as well, such as fishing or golf… one of my once upon a time students was a prominent member of a golf club right next door to the patch at that time and he said the committee ‘discussions’ could on odd occasions lead to near fisticuffs!
And what about the up and coming drone fraternity, too? I wonder if they are always in perfect harmonious agreement as well…
One point about the Riot is it’s longevity. It’s been around for a while now and it’s still a popular model, at least in our little club anyway. I feel that if it were not such a success story it would have fallen by the wayside long ago. It’s willing in any weather, you can sling a few lipos in a warm bag and have a little session on a windy winter’s day if you are so minded. I reckon it’s also pretty tough; as I said before, regarding mine I’m firmly convinced the aileron servos went far beyond the expected call of duty without ever failing; and in common with other of my models I often wondered at what point the wings were going to fold… Whilst the undercart is perhaps not of the best it also seems that even this generally survives the rougher runway at this time of year ok. For the price I think it’s value for money compared with some others.
So there we are… Riot threads have run in the past here on the forum, I’m sure they will continue to do so in the future. And if the adage ‘Any publicity is good publicity’ is true then no harm is done; and I can say I have no connection whatsoever with Century either…
All good luck with your model!
With the greatest respect of course, but may I ask if you think that all Riots ‘are from the outset, marginally powered?’ Or is that just some models? Or have I totally misread that anyway? I’m only asking because in my experience I would think that a standard Riot does at least have adequate power.
The chap flying the Riot in the video that I highlighted, one of the first and using (presumably) the rather limited recommended first flight control surface movements, in a 16mph wind gusting to 29, made a pretty good fist of it in my humble opinion, but by the same token and with the best will in the world he could have only done this with sufficient power available. In the past I’ve flown other models belonging to other people that were less capable than that, both i/c and electric.
From your first flight description I still tend to think that your power train may have some sort of a problem; therefore it should be possible to find out what it might be.
Also it’s possible to upgrade the performance without too much hassle and expense. I simply changed to 4 cells and a different propeller. I only did the servo mods because I thought that the existing setup was not really capable of coping with the increased power and speed, at least in the fashion that I was flying it anyway. Of course, other pilots that use 4S may well be more than happy with it as it is.
With a measured 33.3 amps of current flow at full throttle I also felt this was not really going to overtax any of the hurry up stuff in the front either; and indeed, when I checked occasionally everything was well within the hot limits. That’s only another of my ‘for better or worse quirky ideas’, if a component is cool and collected under all conditions there is unlikely to be any excess current to cause it harm. Maybe all that extra air rushing though the cowl at high speed was helping this effect. A beneficial result from unexpected consequences for once.
Just a few observations in an idle moment really, simply my curiosity rather getting the better of me…..
Reading Nigel R’s little comment about having to glue the rudder in it’s plastic holder reminded me that on the first turn of the first flight of the first Riot that I assembled the fin/rudder popped out of that same holder and was instantly flapping around in the breeze, just held on by the pushrod and quick link! Fortunately no harm done though, and I simply super glued it back in. I found the other models to be the same so I zipped over to the LMS where I’d bought them to warn future customers; he also then went back to Century but it was as an advisory rather than a complaint. Also a post on the forum here at the time, too. This was circa. summer 2013, hopefully it’s all been sorted by now!
I never felt that the Riot was particularly lacklustre in any way. On three cells a lively and friendly puppy. Just a nice universal trainer and hack etc. model. The flying weight was just about 3lb as I remember; as in, cop this one, one of the first Riots. The school I mentioned was a rather Upstream and Country Life sort of establishment, all Drophead Bentleys and Rolex watches; and before you could say ‘You have control’ the lads had got a FPV camera bolted on the top and a small GoPro video camera slung between the undercarriage legs so they could watch themselves filming themselves whizzing up and down the strip! I’ve still got some of that on an SD card they gave me. To all intents and purposes the extra weight and drag seemed to make very little difference to the flying characteristics.
I always used the standard battery size, and with the steel weight removed it was nice and light with a wing loading around 12oz/sqft. which I think was one of the reasons for it’s at least reasonable capabilities. I tried the 4 cell setup just to see what it could be made to do, I’ve always gravitated to flying fast close the ground at times, which can often be rather spectacular… and expensive!!
Only had one problem with the components, we had a motor that suddenly started stopping, usually with the model right in the wrong place; sorry.. I thought it was a connection perhaps but t’was the ESC. A quick email to Century and a replacement crossed the returning one in the post. Excellent stuff.
I have to say that if I had a rather unenthusiastic Riot I’d not be able to resist kicking it around a bit until I discovered what it’s particular ailment was. For one thing, I would have undoubtably learnt something anyway and it’s always useful knowledge to be able to pass on to someone else in the same circumstances.
All Power to your Prop!
PS Bruce - I have read that the spec. of many proper man sized industrial cells are deliberately under rated to guarantee that they would past the commissioning test. Or at least that was the case many years ago in a working life… not sure if that’s still the case nowadays.
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