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Member postings for Clifford Stone

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

Thread: Balast?
23/12/2014 16:16:43
Posted by Tom Satinet on 23/12/2014 14:49:13:

IIRC I saw on a post on rcgroups by Joe Wurts where he said he ballasts so that his min sink settting is not flying backwards for a given wind speed.

The amount of ballast really depends on how light the model is and other factors, such as how fast it flies (etc). Obviously at a basic level ballast increases you ability to cover the sky, which is why people tend to fly it when it's windy. i.e more windy more ballast.

yes I think it is mostly suck it and see because ballast is quite airframe specific, and also condition specific. There are too many different conditions you can encounter for there to be a ballast check list IMHO.

At 1500g your model has a very low wing loading. to be honest 14 ounces of ballast is not that much. I think a lot depends on your thermal tactics. Some people seem to rely more on the low minimum sink rate of the model rather than its ability to cover ground and find lift. 12mph on the ground will be a lot more once you get higher up.

Edited By Tom Satinet on 23/12/2014 14:51:12

Hi Tom thanks for the reply. As you will have realised, this is a learning curve for me, my first season having just passed, reasonably successful in that I won the Ipswich club glider trophy. I find following thermals down wind hard, going against the grain, knowing that getting back is the issue, hense the ballast, as well as searching for thermals and good air. To fast and I find it difficult to recognise before I have passed through.

As I say, my club mates are very helpful encouraging me, passing on tips despite the fact that we are competitors in competion.

CJSF

23/12/2014 13:43:05

Mmm . . . if it had been only a 'gentle breeze' Steve, I would not need ballast . . . wink

CJS

23/12/2014 13:17:08

Mmm . . . no takers, then I will assume it is 'suck it and see'. Very much the way I have gone about the very steep learning curve in 2m. Although one has to be very appreciative of the help one has received, especially in the power train department, which can get very confusing.

I have don a lot of trial and error on ballasting my 2m Sapphire, flying weight 680grs, then ballasted with 140 grams, this combination works really well in winds up to about 15-18mph, (it is possible to carry 200grams, but this turnes here into a brick with wings). As said, this has been trial and error but seems to keep Sapphire competitive with air frames that are better suited to winy conditions, its then all down to the pilot.

So applying the above logic, Pulsar 3.6m, will start with 180grs increasing to 270grs via 30grm and 60gram slugs? Suck it and see, the 90gr slugs are deliberatly that size to go along with my thinking and the fact that a strip of 3mm lead flashing x 6" x 1.1/8" weighs that! The floor is designed to take that dimention as standard.

Looking at the weather prediction for East Anglia, I might get a few hours flying on Boxing day and have the opportunity to try the 180grm setup? Pulsar is still in the early stages of trimming out, seeing what setup suits what conditions and simulating competition flights . . . Fortunatly there are a few pilots in the club who are interested, so we fly against each other and compare notes, it can get very intense on occasions when 'the competitive red mist comes down'.

CJS

20/12/2014 19:42:21

I'm moving onto open class in F5J and Bartletts e-soaring in 2015. I have enjoyed 2m, so a move up seems a good idea? However, my open gliders are light, under 1500grms. One I want to keep that way the other, a Pulsar 3.6m MkI type, modified to be able to get at height limiter and battery with out dismantling half the model.

I was told the other day by a very experienced pilot, that the Pulsar is under estimated in its abilities in windy conditions. So I decided to have a look at the option of ballasting for wind. There is plenty of room, I have constructed a platform under the CG on which I can mount up to 14ozs!!! . . . in 3oz slugs + one 1 or 2oz slug, the whole bolted to the floor.

The question, is there a criteria for ballasting or is it suck it and see, and where do you think I might start if say the wind was 10 or 12mph . . . or more?

Thanks, CJS

Thread: RX/TX binding
09/10/2014 18:53:54

Well, I have to be fair to Puffin Models, their reaction to the poor quality Graupner Spinner was quick and personal with a phone call. In the mean time I have made it fit, never the less they are sending me an HM spinner as a replacement and recommendation . . . from that you can come to your own conclusions?

Thumbs up for Puffin Models.

CJS

08/10/2014 19:43:18

I have been a modeller all my life, RC from 1969, stopped in 1996, then resumed 3 years ago. It has been very evident in the past 3 years that quality of modelling goods has gone down . . . don't seem to make any difference when you bring it to the retailers/sellers attention . . . no one cares?

I have just opened a 45mm Graupner folding prop spinner, cost £19 including postage, of the seven components, four don't fit!!! See what Puffin Models have to say to my email?

CJS

08/10/2014 17:14:33
Posted by Steve Houghton 1 on 08/10/2014 16:04:20:

Hi Cliffird. I too am an A9 user,and with gliders too. I can't say I've had any problems with losing the bind as you've mentioned. If I've been binding a new Rx and held the button on the Rx down for too long, then I've lost the bind on all my other models, which was very frustrating at the time, but ive learned from my error now

Steve

A470soaring.blogspot.co.uk

Hi Steve . . . Mmm, how long is to long? Maybe this is my problem?

Another point, the 'lose bind' is not confined to just Hitec RX;s.  For the Shadow that I'm currently fitting out I picked a universal FrSky RX, that was bound but never used 6 months ago, it needed rebinding yesterday before I could use it.

CJS (Cliff)

Edited By Clifford Stone on 08/10/2014 17:25:07

08/10/2014 15:35:35

I have a Hitec Aurora 9, had it for about 18 months, 1.9 firmware.

I'm very happy with it in general although I had to have a new mother board in July, problems with bugs by down loading from the internet so I was told?

I'm even happier having recently found a bit on YouTube that gave me the key to the more complicated progaming requirements in glider mode on the A9.

However, one issue I still have not been able to sort out . . . If I dont use a RX for 3 or 4 months, it 'requires re binding'. Not a major issue but I was wondering if anyone else has had similar experiance with the A9?

. . . Not only did it cost me a new mother board in July, it cost me a new car as well.

I drove the 90 or so miles to J Perkins from my house, they did the job while I waited, great service. However, the traffic jams that I got involved in both ways at the Dartford crossing highlighted a serious problem with my left knee, boarder line, 'do I stop and ask for assistance'! I took delivery of a new automatic car a week ago, nice to have a 'new car' but there was nothing wrong with the old one, it was only 5 years old . . . frown

CJS

Thread: 'C' rating . . . how much do we need?
30/09/2014 16:12:16

Hi Ed, very useful personal experiences that. It about sums up how I try to do things, and the sort of battery packages I have.

Your fun/practise flying is very similar to mine when on the field by myself. However, there are half a dozen of us in my club who fly the competition type e-glider. We get to the field as often as we can as a group, all retired so that is as regular as the weather and 'she who must be obeyed permit' wink We spend 3 or 4 hours in friendly competition with each other, full fit out, watches, spot and all, great fun, excellent company and ones flying improves, I think? The banter is good and I always enjoy the lunchtime pick-nic. These semi serious sessions highlight any problems in technique, model trim and we draw on each others experience. I still haven't don much good at the competitions, first season so lots to come, there are a couple in October then its all over until next spring.

Be flying in 2m and Open class next year, been working on Shadow today, servos are in, found a small ding, waiting for the glue to dry. Then its programing the Hitec Aurora 9, A daunting task with my dyslexic problems, but I get there in the end, just takes time and patience. If I get a problem my mates at the field always help.

Thanks again for your experience, CJS

 

Edited By Clifford Stone on 30/09/2014 16:13:04

Edited By Clifford Stone on 30/09/2014 16:13:57

Edited By Clifford Stone on 30/09/2014 16:14:14

30/09/2014 12:48:41

That was very good and informative.

We have establishes that a fairly standard 25c-30c battery will serve my needs. What advantage, if any, would it be to use 40c or even 60c rated batteries, obviously their burst rate will be considerably higher but I am looking at the continuose rating as practical.

CJS

30/09/2014 01:21:53
Posted by John Privett on 30/09/2014 00:57:57:
Posted by Clifford Stone on 30/09/2014 00:32:36:

Theory of new model:

Motor is rated at 45amh max, ESC is 70amh, proposed battery is 3 cell 1800amh 60-130c

1c = 1.8A, 10c = 18a, 45amh is 4.5x18 = !!!

If my understanding is correct, I'm looking to keep the amps drawn to about 35?

OK, so the motor is fine for up to 45A. The ESC is rated at 70A so will be fine at the 45A limit for the motor.

45A is only 25C for that battery. (For that battery 1C = 1.8A, so 45A = 45/1.8 = 25C) As the battery is rated at 60-130C then 25C is well within its capabilities.

OK got it . . . 1c is 1/10 of the battery capacity, divide that into the amps drawn shown by the watt meter in this case 45a -:- 1.8 = 25c . . . that makes sence. Sorry if I have re written what you have posted John, but it put it in my dyslexic mind in a way 'I understand'. I have discovered over my 67 years that I see things differently by translation, so the rewriting or repeating my way in the case of face to face, translates a description so that I understand . . . Doh!

You are all very helpful and patient guys, thank you.

CJS

30/09/2014 00:51:22
Posted by Dave Hopkin on 30/09/2014 00:18:31:

Hi Clifford

Looking at the motor you mentioned **LINK** i Assume?

Its rated for 2-5S LiPo with a max wattage of 830...with a max current of 45A, but on 3 Cell you wont be seeing 830W, more like the 500 ish you mention.... that should be enough to fly it to altitude - after all its not meant to prop hang is it!

And some thing like a 1800Mah should give you a decent enough power run without undue dead weight for the main event of the flight, the gliding bit......

After that it will come down to playing with props to find the best on for it........

If you wanted to increase the length of time of the power run a battery with a bigger Capacity (MAh) would do the job- at the cost of more dead weight of course....

Hi Dave that it, the whole thing is theory at present, although I have all the hard ware as yet uninstalled. I'm simply concerned I don't over stress anything . . . although in the competition environment one will take things to the limit.

As you say, props are the final factor to get it right . . . 30 seconds of climb to 200m with the aim to 'glide' for 10 minutes and land on a sixpence! (an unaided, no thermal flight is 4 to 5 mins max). Am I mad or what . . . perhaps I'm kidding myself, as I said, I'm wondering if the other pilots use small motors with gearboxes to address this 'power' issue?

I always do things different, its this strange dyslexic mind I have, approach a problem from a totally different angle than normal, cos' I'm not normal, tell me it cant be done . . . I will find away.

CJS

30/09/2014 00:32:36
Posted by John Privett on 29/09/2014 22:52:17:
Posted by Clifford Stone on 29/09/2014 20:11:46:

OK Dave, I always use a watt meter to see power (w) and be sure to keep within the amp spec., of motor and ESC. But its the current bit I dont understand how to interpret?

OK, so you know the current that the motor is drawing - by using the wattmeter. Ignore (for the moment) any figures it shows you in Watts, the current in Amps is what matters. Let's say, for example, you find it draws a maximum of 66A, (as your ESC is rated at up to 70A then hopefully the actual current will be a bit less than 70A!)

Now turn to the batteries. If you're using a 2200mAh battery then 1C is the current that is numerically the same as the capacity of the battery. So for a 2200mAh battery 1C is 2200mA. Which is 2.2A. So 22A would be 10C, and 66A (who says I cheated by choosing that figure as an example!) would be 30C. And for the 1000mAh batteries, 1C is 1000mA, or 1A, and 66A would be 66C.

So you'd be pushing the 1000mAh batteries beyond their 25-50C rating, but be reasonably within the 25-50C rating for the 2200mAh batteries if you're only running for a short length of time.

Mmm, getting a bit confused, lets take facts from an existing 2m e-glider I have. I gives almost 300 watts of power on the meter, ignore that. I draws 20 amps, and uses a 1000mah 3 cell battery rated at 25-50.

My dyslexic mind says that 1c x20= 20c, batter working with in its constant 'c' rating . . . ?

Theory of new model:

Motor is rated at 45amh max, ESC is 70amh, proposed battery is 3 cell 1800amh 60-130c

1c = 1.8A, 10c = 18a, 45amh is 4.5x18 = !!!

If my understanding is correct, I'm looking to keep the amps drawn to about 35?

Raises the question how far can one encroach into that burst figure . . . if at all. The motor run is 30 second max.

This might be telling me why they use small motors?

CJS

29/09/2014 23:56:09
Posted by Chris Barlow 1 on 29/09/2014 23:06:12:

You can also increase the power from the battery by increasing the capacity to maybe a 3000mah for the same c rating as the 2200mah.

If you need more nose weight it might as well be in the form of a bigger battery than dead lead!

It's also easier on the wallet!

That another part of the equasion Chris. All this is currently theoretical, it is an option I will look at when she is at the check 'CG stage'.

There is also the use of 4 or 5 cell Lipos . . . they are very big birds, over 12ft, not 'fast', small props are not the best idea but it is there as a possibility? Its simply having the knowledge at hand to try as required. For instance a 4 cell 2200amh with a 12" prop might be an option?

I am told some of the really serious e-glider guys take 12 months to get a model trimmed and powered to perfection. Me, 12 days is a long time . . . laugh

CJS

29/09/2014 23:39:25

Hi Dave, makes sence I think . . . 11v -:- by say 500 Watts = 45 That makes one sit up and take notice . . . surprise

If I am understanding that correctly, sorry I'm not the sharpest knife in the draw when it comes to maths of any type, I have dyslexic problems with numbers (and spelling, you may have noticed) that makes things really difficult.

The theoretical watt figure is what I need or am hoping for? These big birds weigh 2kg+, near vertical is desirable? The previous owner of my Shadow tells me she weighs 2.2kg ready to fly. I might be a bit ambishus at 500 watts, if achived I need to be looking carfuly at 'c' ratings. However, seeing other biggies fly, they don't climb anything like vertical, sacrificing power for lightness, small motors turning 16" even 18" props with a large pitch through gearboxes to get efficiency, 'flying' the aircraft to height rather than dragging it there? This small motor requirement is forced by some designs having very restricted nose diameter, fortunately Shadow has a generous 44mm.

I'm hoping, the direct SK3 Glider Drive approach will do the business?

Thanks again Dave.

29/09/2014 20:11:46

OK Dave, I always use a watt meter to see power (w) and be sure to keep within the amp spec., of motor and ESC. But its the current bit I dont understand how to interpret?

Puffy Lipo, occasionaly I discharge to 14%, I will have to rethink, thanks.

CJS

29/09/2014 19:55:04

I'm moving on to big birds, 3.7m Shadow to be precise, I finding the eyes are not what they used to be and my 2m e-gliders can get a bit small in good lift. The 12ft jobbies are very visable at the same 350-400m height! At 350m+ its panic time with 2m e-glider, full flaps, down elevator, a great adrenalin rush but the 'old' heart does pound!

I picked up a shadow this weekend, its been well flown but loved and has a good few wins to its name. I have to put a power train in and radio, then we are away. The motor, prop, ESC chosen is: Turnigy SK3 Power Glide 830kv, 45w, 70a SESC I'm planing on using the recommended 14x10 folding prop, (actualy I have a Graupner 14x9.5) ease the load a tad? This will be driven by 3 cell, 1800mah Nano-tech batteries 'A-type', 65c - 130.

My question, how much, if at all is 65c over kill. I have some 25-50c Nano-tech's, 2200 and 1000amh, could these be used, bearing in mind, the motor only runs for 30 seconds max, albeit at full power?

I have heard, we over estimate the 'c' draw of our motors . . . any help or comments would be appreciated, before I commit to buying any more 'high c' rated lipos? I have also been told the high c rated batteries have a short life compared with more modestly rated units . . . Not sure about that one, my Nano-techs are getting puffy and old just a year old.

CJS

Edited By Clifford Stone on 29/09/2014 19:57:12

Edited By Clifford Stone on 29/09/2014 20:00:12

Edited By Clifford Stone on 29/09/2014 20:04:27

Thread: 3+ meters?
11/09/2014 13:28:43
Posted by Ernie on 11/09/2014 13:00:08:

Hi Clifford, I've just finished a 3m Bird of Time, and a fine big bird it is. You can buy both an ARTF version, and one that you construct from ply and balsawood. I've added spoilers, and an electric motor. Also, I reinforced the wing centre section with carbon fibre

ernie

Hi Ernie, I have a factory produced ARTF 'Bird of Time', that I have converted to electric. A fine machine, great for sunny afternoons at the club field, but not the F5J competition theremal sniffer that I'm looking for.

CJS

11/09/2014 13:23:59
Posted by Tom Satinet on 11/09/2014 12:56:23:

is the spinner size a major deciding factor or something?

I would have thought that once you get the model it would be very easy to find the right size spinner as they are both cheap and readily available.

Yes, spinner size is critical. I want to use the new Turnigy 38mm direct drive in 'runner/out runner'. This business of small spinners is impractical and expensive. I have 2m gliders, its like getting a 'quart in a pint pot', an extra 2 or 3mm would make all the difference, having little or no affect on penetration IMHO.

The sizes that are being used in some aircraft seem to be a combination of 'the pod is from a glider' with the nose cut off, how can we sell the idea . . .? . . . !*!*: 'small = better penetration'. Perhaps thats my synical side coming out? Long, straight pods will potentialy create drag, think, 'airfoil compared to flat plate'?

However my main consideration, cost and practicality is far more important to a pensioner . . .

CJS

11/09/2014 12:37:47

Tried on 'flat field', no response?

I'm looking at Reichard Cirrus or Mandarin gliders. Looking for information on how they perform, has anyone any personal experience of them, and what size is the spinner?

T9 seem to think the Mandarin is a better enginered product, but YouTube shows the tail is not so rigid? T9 cant help me with spinner size either, guessing at 44mm?

I'm looking for resaonably priced 3m+ to have a go open electric, molded composites are out of my reach, unless I can find a used one, any suggestions?

CJS

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