Richard Clark 2
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Posts posted by Richard Clark 2
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Posted by PatMc on 01/06/2020 00:45:08:
I gave valid reasons why reducing the wing incidence is not a good idea.
Although I mentioned that I had set the downthrust at 5 degrees when I built the model in 1986 I also said if I were to build a Jnr 60 now I would not incorporate any downthrust.
The instructions of the Flair kit that I built the model from suggests using downthrust of between 3 & 5 degrees depending on engine used. I don't know whether or not the KK instructions suggests using any downthrust but it was common for the building notes of free flight & rc models of the era to make a similar suggestion even when none was shown on the plan.
It's incorrect to suggest that the KK Jnr 60 had a rearward cg as the cg isn't shown on either version of original KK Junior 60 plans. The Ben Buckle & Flair plans show what would be considered today as "normal" cg positions.
I suggested using elevator trim to change the "decalage" in order to allow the model to be flown at whatever speed would suit the prevailing wind strength.
Having high "decalage" & rearward cg does not preclude using normal elevator & motor control when landing nor does it make landing any more difficult than having low "decalage".Not using your ill considered wing incidence changes won't "make the rc side of it more pleasant WHEN YOU UNKNOWINGLY force the plane into flight attitudes/speeds both high and low a free flight plane could never get into" nor will it increase the risk of such a situation when flying vintage or any other models.
Edited By PatMc on 01/06/2020 00:46:27
Today, with radio control giving the ability to 'flare' for the landing it is just plain silly to make the wing give lots of excess lift by setting the wing at a high incidence relative to the tailplane and simultaneously opposing that excess lift with engine downthrust. The original free flight idea of downthrust was ONLY so the aircraft would automatically slow down when the engine stopped and the downthrust ceased.
However, we are not killing babies here. It's just a toy plane. So you play with yours however you want and I will play with mine my way.
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Posted by Barrie Lever on 31/05/2020 21:15:34:
Frank
No I think the UK government should be funding and promoting this kind of thing.
A small part of my professional work is in the UAV business so I benefit from this kind of research.
I live in the Solent area and know the take off site well and the stretch of water, I guess I did not like the hype.
Regards
Barrie
It's sponsored by a couple of commercial outfits and a charity that does work in 'undeveloped' countries. The university is well known for both its aircraft and 'autonomous' work and may even be making a profit (or at least covering the costs of further educating its post graduates).
Edited By Richard Clark 2 on 31/05/2020 23:04:49
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Posted by Christopher Morris
Hi, the problem was i spent the winter getting things together & now would of liked to get some lessons. But 6 weeks ago the problems started & my club still says it will be at least another 5 weeks. So a suggestion was made to take my Bixler out that i have as its a very forgiving plane. Someone said there was some areas at my nearby coast that should be good on a carm day. So i thought i would check if the area was ok to fly in. & had a look at dronesafe.uk as this part of the coast it is known as an RAF bombing practice area. The site didn't show a thing. It also didn't show many other local areas of drone restriction.that shows up on other sites.
Must admit, i was put off the site straight away as the 1st paragraph i read had 6 acronyms & as a newbie, i got the UK one & had to look the others up, but had to add radio control to my search or got Under Armour sports clothing company instead of unmanned aircraft.
This was the 1st paragraph. "Great for newbies" Seems like a union rep wrote it, lolUK FRZ Map
This map enables UA operators to remain clear of the new UA FRZs that are created as part of the latest amendment to the ANO.
There's FAR more to it than the ANO. You can't just fly anywhere it is not formally prohibited.
On the other hand me and a couple of mates have flown small(ish) slope soarers from a small 'linear' hill on the Hampshire/Wiltshire border for years. Who owns it is not obvious as it's 'downland' with no crops, farm animals, or houses nearby and very few 'passers by' on the almost unused unfenced public footpath, and nobody has ever tried to stop us.
Edited By Richard Clark 2 on 31/05/2020 22:28:55
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Posted by Steve J on 31/05/2020 21:37:44:
Posted by Richard Clark 2 on 31/05/2020 20:52:33:
There is a whole 225 square miles (the New Forest) that it says is ok. But there is no model flying allowed at all except in one specific area of about 2 square miles.
The park authority can say if you can take off or land from their land, I am not aware of a law which gives the park authority control over airspace.
Both the Park Authority and the Forestry Commission simply say "No model flying" without any nerdy details. And there's a bylaw that says the same, The Beaulieu site is a formal 'exemption'.
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Posted by leccyflyer on 31/05/2020 21:09:22:
To be quite honest though, it appears that the OP is a beginner, just starting out in the hobby and realistically, this sort of thing really isn't all that necessary to know, to that degree, at that stage. Neither is a definitive list of which radio frequencies we are able to legally use.
There is enough of a learning curve learning to put an aeroplane together, prepare it for flight and get through the early stages of training, at the club field, rather than worrying about where exactly one might be able to legally fly. Just take the advice of the club, which knows the local situation best.
Yes.
A couple of days ago he was worrying about allowed frequencies.
As you say, there is a steep enough learning curve without this, let alone legal radio frequencies. And if (at present) a radio purchased from a legitimate UK model shop, brick or online, (as opposed to some unknown bloke on Ebay and the like) is CE marked it's legally ok and that is all you need to know.
Further, you can't just fly anywhere you fancy just because it isn't marked as 'prohibited' on some map or other.
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Posted by Christopher Morris 2 on 31/05/2020 14:11:35:
Ah! well done Steve. Way better info & simple to understand than the Drone safe site with good reasons & explanations on why not to fly in certain areas. Have bookmarked this one for the future. Just got to see if i can use it & overlay the National trust map on top for my area. Thanks
Problem is it's wrong.
There is a whole 225 square miles (the New Forest) that it says is ok. But there is no model flying allowed at all except in one specific area of about 2 square miles. Not at ANY altitude. And there is no "May be prohibited" about it, And that has been true for at least 20 years.
I live there so it's the only place I looked. As it's wrong there it is likely wrong in lots of other places.
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Posted by eflightray on 31/05/2020 14:39:41:
Southampton University has recently flown a UAV from Southampton to The Isle of Wight for transporting medical supplies.
It's rather large, (like enormous, though couldn't find any dimensions),
has a range of 1000km (620 miles) and can carry a payload of up to 100kg in a hold around the size of an estate car boot. --
Good that. There's a NOTAM (Notice to Airmen) about it. May be flying between 08:00 to 12:00 BST any day between 6th May to 30th June.
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Posted by Christopher Morris 2 on 31/05/2020 11:15:57:
Hi, i looked at this site & its not very good. IE: just 2 miles from me in Kings Lynn there is a small/tiny landing strip that shows up on some sites but not this one. We have the RAF use the north side of the Wash area in Lincolnshire for low-level bombing runs on a regular basis, not on the map. We also have a lot of national trusts wildlife areas that your not allowed to fly over. Not on this map. It's not easy to see where you can fly legally & not be infringing on areas that are a no go zones. .This is something the BMFA should be telling us on a single map for everyone.
Edited By Christopher Morris 2 on 31/05/2020 11:33:16
As others have said, you really can't expect the BMFA to keep track of all this stuff and keep it up to date - it would be a 24/7/365 job. Nor in fact can any other single organisation.
For example, the CAA keep airmen (and presumably air ladies too) informed about 'air' restrictions via NOTAMS. (Notice to Airmen). This used be via airfield teleprinters, now it's on the Web. And they can be long or short term.
The last one was at 19:05 today (20 minutes before I started typing this) and there have been FIFTY FOUR in the last 24 hours. This is 'quiet', what with it being a weekend and coronavirus restricting flying, private and commercial, as well.
And as Leccyflyer mentions, there are 'private arrangementa' with the local air traffic control and other authorities. We have one with Southampton ATC, for our model flying field, giving us an exemption from the 400 ft limit, the small local full-size flying school has an 'overfly' exemption, (but nobody else has, model flyers included), and so on.
Then you add the National Trust, the RSPB, the Forestry Commission - with our site there is a 'ground nesting birds season' no model flying period, farmers, other private landowners big and small, local byelaws, etc etc. etc.
So it's totally impossible for any one organisation to keep track of all this, much of which is constantly changing.
Edited By Richard Clark 2 on 31/05/2020 20:14:38
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"reducing the wing incidence is not good idea"...…."I fly my J60 like a J60"
Comment such as these miss the entire point. And PatMc promptly added 5 degrees of downthrust when the original didn't have any at all. Though his "no sidethust" is correct to the original.
The original was a free flight model. Under power it flew at a fixed airspeed (the optimum and constant climb rate for the UNCHANGING power available) in a gentle left (usually) turn due to 'torgue' or the corkscrewing propeller wash ("or" because opinions differ on why they turn to the left).
The rudder trim tab was set to turn the plane to the right. This was to 'open up' the left turn under power and hopefully avoid the dreaded power on spiral dive. It had the pleasant side effect of making the plane turn the other way on the glide.
And the high 'decalage' together with the rearward (by rc standards) C of G had the desired effect of a slow 'landing' with no elevators in often far from optimum circumstances. It's not a 'landing', it's a slow as possible uncontrolled crash.
My suggested changes will not affect the flying characteristics at all. They merely make the rc side of it more pleasant WHEN YOU UNKNOWINGLY force the plane into flight attitudes/speeds both high and low a free flight plane could never get into.
BTW: Power choice is a problem. Electric has advantages though the sound is not authentic, two strokes are 'period correct' but sound unpleasant. I use an OS 30 four-stroke, and what's more, a 1970's US made 'Pro Line' radio (the absolute 'tops' at the time but never imported into the UK) modified to 2.4 and only 20 years out of period.
Edited By Richard Clark 2 on 31/05/2020 03:18:22
Edited By Richard Clark 2 on 31/05/2020 03:20:59
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Posted by leccyflyer on 30/05/2020 08:32:05:
You are correct, Aveox didn't make brushed motors, though they did make brushed controllers. It's the Astro Cobalt and similar motors that the 100w/lb rule of thumb was based on. Other quality brushed motors were similar quality - like the Plettenberg Ultra, Mega R7 and the like. Those were much better than the typical can motors, but much more expensive.
There were less pricey alternatives available - some of the Kyosho buggy motors with removable brushes and adjustable timing gave a useful hop up in power levels without breaking the bank. They also benefitted greatly from optimising the timing, fitting better bearings etc and allowed decent perfomance in the days before brushless motors and lipos were widely available.
As I'm sure you know and contrary to modern perceptions, it was definitely possible to get decent electric flight performance back in the day with Nicds and brushed motors. it just took a bit more care and a bit more work. I've just been recalling this morning about the electric fly-ins in the early part of the millenium, before lipos, and we had a lot of fun and saw some very good performance from well thought out setups and even some cheap and cheerful ones.
Yes . We had a lot of fun in the 'old days'. I started electrics because they were 'quite difficult' at the time. As soon as something gets more commonplace I tend to lose interest. Though I still build electrics up to about 50 inch span, glows above that. I am tempted by petrol but most of the engines are a bit big for the size of planes I like. I've got a 'Warbirds' Spitfire Mk9 kit coming in the next few days. It will replace the slightly larger, hopelessly inaccurate and grossly overweight 60-90 size TopFlite one I have - even the model shop owner warned me it was very heavy.
I once tried am un-named 480 size samarium-cobalt/ball-raced/adjustable timing brushed motor from J Perkins. It was hopeless. The Astro ones were fine but the expensive s-c magnets are no advantage over neodymium ones, brushed or brushless. They take a much higher temperature than neodymium without losing magnetism but that hot the motor will be in its very inefficient range anyway. BTW Astro is still gong
After a lot of fooling around with expensive ply/balsa or composite 90mm EDF kits , for the last couple of years I have concentrated on 'fun for the money' and regular planes plus a couple of 'semi-hotliners' beat them any day
Edited By Richard Clark 2 on 30/05/2020 09:29:58
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1) Battery is too small for safety.
2) Nimh batteries drop voltage very suddenly if near flat and under load but falsely appear to 'recover' if the losd is removed.
3) Memory effect. If only partly discharged when recharged they can drop voltage under load when they reach that previous partly discharged state. Fully discharge them (most chargers can do this, if not use a torch bulb or car brake light bulb) and then rechsrge them
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Posted by SIMON CRAGG on 30/05/2020 06:48:09:
Thanks to everybody!
I don't think you really needed any help at all. Just as I only use a wattmeter to check my wild guesses, we are only a check
Edited By Richard Clark 2 on 30/05/2020 07:26:16
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Reduce the incidence on the wing slightly (or increase it on the tailplane, which is easier if you have already completed the fuselage sides) and put the motor level with the nominal centreline of the fuselage.
RC is completely different from free flight (which is at a steady speed with incidences mostly meant for slow landings with a stopped engine, so no downthrust at that time) and without a moveable elevator.
These changes will be worthwhile. It will still climb with increased throttle but compensate for it with the elevator. Manually, not with a throttle/elevator mixer as that will screw up any 'touch and goes' - open the throttle and it will promptly nose over or dive if it's off the ground.
Bear in mind that "The elevator controls the speed and the throttle controls the height". Many modellers get that backwards
Edited By Richard Clark 2 on 30/05/2020 07:10:19
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Posted by leccyflyer on 29/05/2020 22:48:48:
Geoff - although the 100w/lb rule of thumb was indeed derived at the time when most folks were using rather inefficient can motors, it was actually based on the higher quality, more efficient brushed motors, such as Astro, Aveox and the like.The motors were not much less efficient than budget brushless motors.
The history of our model plane motors is interesting.
It all started with the successful 1940's 'round the pole' efforts by 'Aeromodeller' staff with a Miles Magister and their later 1940's rtp EDF DH Vampire. Then Colonel Taplin (later of 'Taplin twin' fame) with a single channel ED Radio Queen, an American Emerson motor and Venner silver-zinc rechargeable batteries.
Then Fred Militky of Graupner and his small Silentius free-flight model using a Graupner labelled geared T05 motor sourced from an 8mm movie camera and non-rechargeable water activated batteries similar to the ones in some Polaroid cameras. I had one of those but lost it in a flyaway.
Then of course we had the 'can' motors. Mostly made by Mabuchi as 'toy' motors. Available in about four different sizes and a variety of windings. Sold under a variety of model plane names. Exceptions were the Ripmax 'Bullet' and the high-quality Astro Flight samarium-cobalt magnet motors. My first electric rc effort was a Vic Smeed Chatterbox with a geared Graupner (Mabuchi). Speed 400 and a stack of nicads.
Then along came Aveox!
An American 'startup' with a range of brushless!!! motors and ESC's to match. The very first 'consumer' brushless motors and of very high quality. (Aveox have never made brushed motors.) MaxCim, also American, was a later rival but folded quickly.
They were very expensive (hundreds of dollars with the ESC) but I couldn't resist. I geared it down with a couple of thick brass gears and put it in a Flair SE5, still with nicads of course. This was somewhen in the 1980's.When the first Lipo's appeared (from Thunder Power) I used those and it's still flying with the Aveox motor and ESC some 30 years later. Only my Astro Hog (now with an OS 91 glow rather than the original K&B 35). is older.
Aveox gave up on model plane motors by about 1990 and their official history, which starts in 1992, doesn't mention them at all. It's all military and aerospace now, Large UAV motors, , lots of 'stepper' motors, and they made the motors in the Space Shuttle robot arms.
The best motors and ESC's today are probably Kontronik but most British aeromodellers are too tight-fisted to buy them.
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Posted by SIMON CRAGG on 29/05/2020 19:36:43:Posted by Alan Gorham_ on 29/05/2020 13:35:22:
There is an easy way. Watts are not the limiting factor, Current is.
So just prop your motor to stay within the max current limit.
Sorry, but most of the comments make no sense to me, apart from the one above.
Cheers anyway!
100 watts per pound weight of plane including battery is adequate for most propeller.planes.
If they don't give you watts in the motor spec just multiply the max current in amps by the voltage (roughly 4 volts per cell) and you have the watts.
Edited By Richard Clark 2 on 29/05/2020 20:02:41
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Posted by Christopher Morris 2 on 29/05/2020 16:53:27:Posted by Richard Clark 2 on 29/05/2020 15:54:18:
At present in the UK if a piece of equipment has got CE marked on it it's fine to use no matter what's inside.
End of 'problem'.
Laugh! That means no more from China. Can't even get an item from there that has a UK plug or an adapter with a fuse. So you buy a simple 3amp item from China & you then back it up with the main 32amp fuse box fuse. "Very Dangerous" should be stopped.
CE marking is allowed to be 'self-certified' by the manufacturer so it doesn't mean much anyway. And my saying "fine" implies it will actually work in practice so I should have said "legally ok".
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Posted by Dickw on 29/05/2020 16:27:40:
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That statement is correct BUT the losses (heating effect) are related to I^2R and so the 8s version with fewer turns of thicker wire will have a lot less resistance and could be used at higher currents.
In F5B, for example, you might chose to use a 5s 400amp setup or a 10s 200amp setup using the same prop and the same motor but with a different winding (I know - I did it). Power was the same either way, but it is easier to get a slim 200amp ESC than a slim 400amp one and the 200amp setup is easier on cables and connectors.
Either way I was using the motor at about 4 times its rated watts, but preventing it from overheating by using only short motor runs. A lot of variables at play when talking about Watt ratings.
Dick
Yes. I agree with both that and your previous reply to Simon Cragg. And a short motor run at full throttle is only required by my EDF's at takeoff (we have a shortish concrete runway) and verticals. The rest of the time half to three quarter throttle is sufficient.
Motor heat is ultimately the limiting factor. And it's not as useful as some think to add a heatsink. The internal heat is still being generated, wastes power, and I build EDFs, not fan heaters.
In the end with EDF's I use previous experience and a couple of fingers. After a longish full throttle ground run (telemetry tells me that rpm does not increase significant6ly with speed so the fan does NOT unload much, rather to my surprise) if the temperature is 'low' I add another cell and try again. If it becomes 'warm' I leave it at that. Without using careful 'throttle management' but also not flying at full throttle all the time, and NO heatsink I am now getting durations comparable to propeller planes.
Edited By Richard Clark 2 on 29/05/2020 17:16:28
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At present in the UK if a piece of equipment has got CE marked on it it's fine to use no matter what's inside.
End of 'problem'.
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All interesting stuff. But within reason the possibly lower 'quality' of UK judges will still end up with our best F3A flyers.
And just how many 'top' judges ARE there in Austria or Liechtenstein
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Posted by Alan Gorham_ on 29/05/2020 14:25:41:
Your reason for disagreeing with me is due the example you have given of manufacturer offering a motor specified for a given input voltage. I guess that in EDF use it is impractical to vary the current drawn by changing the fan impeller and therefore it is practical to give a max Watts figure in that instance.
However, the point you've chosen to disagree with me on is hardly applicable to the OP's question which was related to the fact that some (most?) motors do not have a max Watts figure quoted.
Yes, you can vary it a little with different makes of fan but that's all.
Re your second point - "most" motors, I just checked OS, Axi, and at the 'cheap' end, Hobbyking (Turnigy), Ripmax (Quantum) motors. So on three of those selected arbitrarily within their price range four the watts are given. And as I explained how it works (which he may or may not need) he can figure out the watts of other brands if it is not given.
Axi, OS, and Hobbyking (Turnigy) give recommended number of cells, maximum current, and maximum watts.
Ripmax Quantum give recommended number of cells and maximum current. They don't give watts.
Edited By Richard Clark 2 on 29/05/2020 15:18:23
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I broadly agree with Alan except for his "meaningless" part.
An example. I'm interested in fairly high power EDFs and have used several Hacker E50 motors, which Hacker rate at 4000 Watts. But in fact this is only true of the ones they say are for use with 12 cells (approx. 48 volts).
Because it is current that heats up the motor windings, not voltage. So a 12S motor has more turns of winding and so the internal resistance of the 12S is higher than the 8S version. So the 12S one needs a higher voltage to push the same current through.
And as Watts is Volts times Amps the 12S one has a higher power than the 8S version. The end result on a typical 90mm fan is 8 pounds thrust with the 8S version and 11 pounds thrust with the 12S version. (The battery weight of the 12S version will be higher for the same full-throttle duration using the same size cells of course.)
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Posted by Christopher Morris 2 on 27/05/2020 12:50:20:
Looks like this is pointed at the EU. Don't think we are part of that club anymore?? You think there would be one simple paragraph with a simple list that said you can use this only in the UK. "Simple"
A list of things you CAN do would get very long. EG: That we can pat our heads while rubbing our stomachs in either clockwise or anti-clockwise directions would need to be on the list.
Also only those who have never exceeded the speed limit would ever worry about whether the referenced Jeti was legal in the UK or not. It is even less likely to be policed than speeding and anyway we could debate whether the use of the Jeti, if illegal, is 'honourable' or not until the heat death of the universe.
Edited By Richard Clark 2 on 27/05/2020 13:44:59
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Posted by Colin Leighfield on 26/05/2020 22:35:50:
I never said they were Richard. Of course Hawks and Vultures spend huge amounts of time soaring. However you suggested that gulls and albatrosses don’t. That is not correct, that’s all and the albatross is known as the best soaring bird in the world, able to travel 10,000 miles in one flight. Look it up.
Edited By Colin Leighfield on 26/05/2020 22:36:18
So I was wrong. Fine. This site is not a competition where we 'win' threads.
One further thought (just thinking aloud) about our gliders, both model and full size. Modern ones have quite a high sink rate but also high speed so they have a good glide angle. Great for covering distance. But for just 'staying up for a long time' the larger wing area/low wing loading given by low aspect ratio is probably better.
So there is no 'best soarer'.
It's all down to what (some of) us humans want for our 'play' or in which way evolution sent a group of birds food gathering behaviour in a variety of circumstances.
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Posted by Andy48 on 26/05/2020 21:48:15:
Number 3 is a Taranis X9D. If I didn't already know its printed on the circuit board.
Edited By Andy48 on 26/05/2020 21:49:06
Rather to my surprise it look better made than the others
Drone delivery service, the shape of things to come?
in All Things Model Flying
Posted
Richard
I know well what the uni is known for, I have worked with them on a number of occasions.
I was not inspired in any way with this project though, and remember I have some bench marks from my involvement in UAV's to judge it by.
I think the exercise was actually to do with a UAV operating in an active airspace.
The Sharmans remembered you.
Regards
Barrie
Edited By Barrie Lever on 31/05/2020 23:53:32
I thought you would probably know that..
As for the Sharmans, I worked under Geoff for some years and got on with him well. I also very much liked his 'co conspirator' who's name was Norman, who I later briefly met by chance, long after we had both retired in the Cricketers pub at Easton, near Winchester.
At IBM I only knew Richard because of Southampton Tech, and I only went there to 'show willing' and left the course half way through, as I believe several others did. I don't think either of us knew the other built model planes.
You probably now realise I am not here under my real name as publicising that can produce lots of spam. Similarly my email name for every purpose, not just here, is just a random string of allowable characters.
Regards..