Here is a list of all the postings Roger Dyke has made in our forums. Click on a thread name to jump to the thread.
|Thread: Motor Ident?|
I quite like the look of them too and on the sizes that I use, do like the 5.00mm shaft which is 4.00mm on a number of others.
Sorry, I accidentally missed you out.
It was in stock around 6th May a couple of months back.
Edited By Roger Dyke on 05/07/2020 17:11:45
Thanks for your info. It will probably go back in the box now as my older years don't really lend themselves to the punch holes in the sky set. Nowadays I'm more of a tootler. Good to find out what it was though. Even if it wasn't my intended purchase.
Yes, the 1000kv one was the one it was supposed to be and what it says on the box.
I think it is exactly the same as the Turnigy D3542 series (but re-badged). Flash Hobby also badge them.
Edited By Roger Dyke on 05/07/2020 12:42:07
Your thoughts are interesting. The more I look into it, the more it seems that the market for this motor is probably for quads and drones (with small fast props etc.). Of course, I maybe wrong (again).
I didn't purchase it from there, but below is the link to the DYS website showing the motor D3542/4 - 1450kv.
The no-load current was 4.5 Amps read back from the wattmeter when running full chat. 0 Amps read at idle.
Pat and Peter,
Just for info. I have carried out the test with no prop as you suggested and the result was as follows:-
So 17300/11.98 = 1440
So I take it that the motor is the 1450kv version. Not the 1000kv version as stated on the box.
Thanks for your help.
Hi Pat and Peter,
Thank you both so much for your useful tips. I'll give it a go.
A while ago I purchased a DYS D3542/6 - 1000kv motor but never used it.
However, I've just installed it on my static rig to run it up and my findings were not as expected. It's spec. is supposed to be 555W, 38A, 1000kv, and 2 - 4S.
Results using a 3S battery:-
I'm inclined to think that the motor is either the 1250kv or the 1450kv version and has been put in the wrong box. The box is clearly identified in two places but the motor has no identification at all apart from the manufacturers label.
What do you think or am I missing something?
|Thread: Prop advice please.....|
Thanks for the useful info. and the benefit of your experience. I too tend to do my own experimenting, but as I have the iCalc tool I thought that I would give it a go. I must say that very often it doesn't come up with the same answers that I get. Still it's useful to do comparisons.
Regarding changing props. Unfortunately, I have already been through the prop experiment with all the thereabout sizes and makes. I've even tried the half sizes, but now think that I've found the optimum in the 9x6 thin APC. Some of the others come close. But none of them any better.
Edited By Roger Dyke on 04/07/2020 16:45:15
It is what it is I'm afraid. The battery compartment is maxed out in width, height and length and I have trawled the websites for any shape and combination of battery that might fit. So that was my starting point. The fuselage is quite narrow and the distance from the firewall to the wing bay former is what it is. I fully understand what you suggest, but if I could get a bigger battery in the bay in any combination at all it would open up all sorts of new possibilities. But I can't I'm afraid. So there we are.
Just for interest. Regarding the 11x6 prop. On my static rig and with the 3542 800kv motor fitted, I tried a few different prop sizes with a 3S battery.
The results were:-
10x7 - 8300, 11x6 - 8500, 11x7 - 8300, 11x8 - 8100. The currents recorded between 28 and 33 amps.
Yes, you are correct. The weight of my battery is included in the amount of weight I need in the nose to balance the plane.
Yes, I can certainly draw more current form my battery or even from smaller capacity batteries, but drawing around 30 amps or so from my 3000 mA battery is my maximum limit that I can draw without impeding my flying time of around 5 minutes.
I was considering doing that as I do have a 3542 800kv motor and which pulls about 30 amps with a 11x6 prop at 8500 rpm (my own tests). However when playing around with eCalc, it didn't show any improvement to performance to what I currently have. In fact it was a little worse so decided not to bother. maybe I might have another look on my static test set-up though to confirm my findings.
Edited By Roger Dyke on 04/07/2020 10:39:45
Thank for your reply. My battery pack weighs 214 grams. There is also a lot of lead ballast in the nose of the model as the motor/battery combo weighs a lot less than the old engine/exhaust/fuel tank (which also had some lead ballast).
I'm not sure what you mean by a battery with a lower capacity and a higher current rating. The power from a battery is the same no-matter how we derive it (volts x amps). Higher voltage with lower amps or lower voltage with higher amps. Size wise and power wise they're the same.
A lower capacity battery would give me less flight time, which at the moment is about 5 minutes (leaving about 20-30% of capacity left).
Thank you for your very kind words regarding my flying abilities. That was very generous of you, but I'm not that good really. Thank you also for your very detailed explanation of how you go about motor and prop selections for your own models which I found interesting. I intend to keep this particular model forever. Even it it has an unscheduled arrival which results in it being grounded as it holds a lot of sentimental value. I also have another one (also converted) which holds a lot of sentimental value which I built in 1973 (Mercury Galahad). It has been repaired so many times but still flies. All my other models don't really hold the same sentimental value, so if they went in big time, they would probably reluctantly be replaced.
With the one in question, my governing factor was the battery and had to work back from there. The biggest capacity battery I could get that would fit in the bay in all directions was a 3S 3000mA graphene type. Then in order to have any reasonable flying time (5 minutes) I had to calculate the current draw that I could afford (about 30A). This then set the scene for the motor and if I couldn't get one that was powerful enough to pull it around the sky the show was over. Anyway, I found a 3536 1050kv that at 30A would turn a 9x6 prop at 10900 rpm with a static torque of 2.9 lb (my own static tests). Not ideal but should work. I did test a few more motors too but found this suited my requirements rather better. So, in this shortened version of the conversion path, this is where I have ended up. I am now reasonably happy.
Thank you so much for your interesting post. You are almost spot on with thinking about pylon racing. I have just looked out the old magazine where the plan came from. The author said that he based the design on the American AMA Quickee Class Rules for the AMA Racing 500 class (500 sq/in wing area) and was designed for hot two strokes or 45-50 four strokes and prop size 9" to 11" diameter with 6" to 8" pitch.
I tried the 10x6 prop today and you are right. It was not quite as good as flying with the 9x6. Also as expected it shortened the flying time due to the increased current. I agree with you that I am operating it way outside of it's design envelope and that is why it "needs flying". It in no way is it stable and it can easily catch you out. Especially as it's powered by electric as you cannot hear the throttle rpm. It was much easier to fly with the IC 40 I used to have in it as I could hear that. I think that I have explored all the avenues without carving up the model so I think that I have come to the end of the road with it now so I will just settle for what it is. After all, it has a lot of sentimental value to me so I am happy.
Edited By Roger Dyke on 01/07/2020 20:29:16
I thank you so much for your your suggestions and I can feel your enthusiasm brimming over with ideas for my CAT 500. I think it was originally designed as a racer for a hot 36 or 40 IC motor. I always used it with a cooking 40 and was always happy with it. In fact, it could be converted back to an IC 40 very easily as everything is still in place. With it's conversion, all I have ever wanted to do with it is to lazily fly it around in straight and level with the odd rolls and loops. that's it. I have no desire to punch holes in the sky with it as it just represents a piece of nostalgia to me and is of sentimental value only as a tribute to my dear friends passing. With the current set up it flies to that end quite well although it does have to be 'flown' and I don't mind that. Perhaps being an ex private pilot might have helped me in that regard. My original question was simple, should I go for the 10x6 prop or not?
Thanks again for your very valued reply.
Thanks for your suggestion. Yes I have. I more or less lived on eCalc for a while. I found it very useful to try out the effect of different set-up's. But the figures never matched what I actually got for real. Usually with the eCalc current was lot less than what I observed in real time. That was with all figures entered as accurately as possible. Couldn't find a reason for that. I know that they claim that their results are to be taken +/- 10% but the difference I found was generally much larger.
Thanks for that. At the moment the plane uses a 3536 1050kv, but I do have two 3542's. One a 1000kv and the other an 800kv. It may be something to think about if my prop swap to the 10x6 doesn't work (or I might just leave it the way it is).
Sorry Shaun, you are right, It's too big. Thanks for trying though.
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