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Author Topic: Winders, winding stooge, torque meters, winding methods  (Read 39335 times)
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Art356A
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« Reply #100 on: August 04, 2010, 04:28:30 PM »

Hi Chris,

Nice to see you on the forums. This thing is still under development. No.5 is like No.4 but I tried to make it a little more accurately, which didn't completely work, so it has a few bushed and redrilled holes in the frames, so I could eliminate the takeup devices. I think the future ones will have takeup rollers, as they seem to have more pluses than minuses. No.5 has a simple reliable stop, and a tongue that slides into a slot in the near end of the base. It has a GizmoGeezer counter that picks up 2 pulses per crank, so you have to add that last zero. Future ones will have a Red Lion Cub3 (I think) which will count individual turns off the hook shaft. If the builder doesn't want a counter he can leave it off, but these digitals are so head and shoulders better than an analog dial, I can't see trying to save the forty bucks or so that they cost.

The present plan is to make up a tutorial for SFA, but I won't do that until I develop it into something that can be easily and reliably built by anyone capable of building a Hangar Rat or a Phantom Flash.

Art.
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Art356A
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« Reply #101 on: August 04, 2010, 05:51:17 PM »

Oh, I forgot. The source for the innards is Servo City. I use two 40 tooth wheels, one 10T, one 8T, and a foot of chain. This runs about $8.50 plus $6 s&h. Everything else is off the DuBro and K&S racks at your LHS. Or HomeDepot if you want to make the frames from Lexan.

I'd love to have somebody else working parallel with me, so we can bounce ideas around.

Art.
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« Reply #102 on: August 04, 2010, 06:05:22 PM »

Hi Art,

Thanks for the information. I will place an order for the parts from Servo City and after I have them in hand get in contact with you. I will be traveling next week so don't expect to hear from me until after August 16th.

best wishes,
Chris
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Tapio Linkosalo
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« Reply #103 on: August 16, 2010, 06:45:02 AM »

So the Belgrade WC saw the first serious action for the digital torque meter. And I must say that I am all satisfied with the results. First of all I learned that I do not wind my motors tight enough, and learning for that would have run out of scale on my mechanical TM. But more than that, the digital meter has so much better resolution, that you can much better see what is going on in the rubber. For instance, I have always known that when I stop winding and hold the motor still, it slowly loses torque. But I never knew before, that if I back off, the motor gains a little torque as it settles to the new position!

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Art356A
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« Reply #104 on: August 16, 2010, 09:45:28 AM »

Tapio...

I'm happy that it's working out in practice, rather than just on the bench. Shows the difference between me, who simply observes the phenomena, and you who knows how to observe, interpret, and put the data to good use. That said, I still think that all the emphasis on elaborate thrust bearings is totally unnecessary because there's no rotation occurring here, only a transfer of force direction. A nylon or teflon bushing more than does the job. The fact that when you stop winding you see an instant drop in torque proves that it's working.

Meanwhile, the effort to come up with an accurate counter on the "Frazer-Nash" winder is costing a lot of time and money, but I think I'm getting closer. As the winder gets more costly and bulky, I'm becoming less convinced of the necessity of a turn-by-turn count, as opposed to counting every tenth turn. Is there really a useful difference between 2512 turns and 2517, particularly when, as the torque builds, you've switched away from the counter and onto the torque meter? Somebody please agree with me, as a 10-turn counter is easier, cheaper, and lighter.

Art.
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Olbill
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« Reply #105 on: August 16, 2010, 11:26:25 AM »

Art

I totally agree that counting individual turns is not necessary. Most indoorists do not use counters at all. For me this means that I long ago learned to think in winder turns instead of actual turns. On my 20:1 winder I have a counter made from a pedometer that counts crank turns. I think I've posted it before but if not here's a pic. I've been using it for a number of years and have been totally satisfied with it. It has a slight flaw in that if you crank too fast it will miss some of the turns. This is actually not a bad thing since cranking fast is a bad idea anyway. The only exception is at the end of a contest period when you're trying to get in that one last flight before time is called.

I think the pedometer cost around $12. The other parts required are a reed switch (from Radio Shack) and a magnet. The reed switch is wired into the pedometer in place of the pendulum mechanism.

I think you're probably right that the torque meter bearing isn't extremely critical. To be absolutely correct though there is some rotation occurring in the bearing - otherwise there would be nothing to measure on the load cell. I actually measured this one day but don't remember the number now. I think it was on the order of a few thousandths of an inch. If the deflection is .005" with a 1" arm then the rotation is about 1/4 degree.
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« Reply #106 on: August 16, 2010, 11:43:57 AM »

You can also use pocket or key ring calculators taking a wire off either side of the equals (=) button and run it to a reed or microswitch. The calculator can be 'programmed' to the winder, which is useful for outdoor winders with difficult ratios such as 3.75:1. For example, with 20:1, you enter 20 +, and then every time the = key is pressed (or the switch activated) it increases the total by 20. As Bill says, the only drawback is that if you wind too fast the switch can bounce and miss turns.

I can't claim credit for this idea, as calculator & microswitch kits are available for about a fiver (£5) from our invaluable cottage industry FF suppliers.

Peter
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Tapio Linkosalo
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« Reply #107 on: August 16, 2010, 11:49:08 AM »

In the champs, my teammates (and others) kept asking me, "how many turns did you pack in?" I could not tell, as I do not count them. Agreed, it would be useful additional information to know, at what turn number you reach a given torque, so I will need to implement a counter later. But, IMO, torque meter is way more important than the turns counter.
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Art356A
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« Reply #108 on: August 16, 2010, 11:51:05 AM »

My two main problems have been a double count at unrealistically slow speeds and missed turns at faster, but realistic, speed. I think the problem is too small a magnet. It kicks, releases, and then kicks again on a slow pass of the reed switch. Bigger magnets are on order. I like the pedometer. If you tried to use it on the output shaft you'd probably find that it couldn't handle the frequency, which could reach 60-65Hz. Anything will pick up 6 or 7Hz.

Radio Shack no longer carries the reed switches, but I have a friend who is a burglar alarm guy, and he has an unlimited inventory of several different kinds and has been teaching me the ins and outs of working with them.

If the bigger magnets solve the problem, then this one will be functional. After that I'll go back to the 10-turn count. Less aggravation.

The beauty of the calculator is that the feed is at cranking speed, and the readout is whatever you want it to be.

To return to the thrust bearing question: Nope, I don't buy it. These scales sense pressure, not travel (like a spring scale). Even if 2 ounces makes them deflect .010 (which it doesn't) the deflection would be taken up by the slop in the system. Again, the fact that the scale registers an instant drop in torque the moment you stop winding shows that it's picking up minute differences in force without the herioc thrust bearing measures.

Art.
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Art356A
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« Reply #109 on: August 16, 2010, 03:20:50 PM »

Okay... success at last... sort of. Bigger magnet and an alarm reed switch rather than a raw ampule type. The double hit at low speeds is cured, and I have to crank it at ridiculously high speed for it to skip.

It'll have to do.

Art.
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« Reply #110 on: August 16, 2010, 04:37:59 PM »

To return to the thrust bearing question: Nope, I don't buy it. These scales sense pressure, not travel (like a spring scale). Even if 2 ounces makes them deflect .010 (which it doesn't) the deflection would be taken up by the slop in the system. Again, the fact that the scale registers an instant drop in torque the moment you stop winding shows that it's picking up minute differences in force without the herioc thrust bearing measures.

Art.

I think they measure bending stress in the load cell. No movement = no stress (or pressure if you want to use that term). Use a feeler gauge under the load cell if you don't think they move.
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« Reply #111 on: August 16, 2010, 04:42:37 PM »

In the champs, my teammates (and others) kept asking me, "how many turns did you pack in?" I could not tell, as I do not count them. Agreed, it would be useful additional information to know, at what turn number you reach a given torque, so I will need to implement a counter later. But, IMO, torque meter is way more important than the turns counter.

Tapio

Both are important. Subsequent winds of the same motor will generally yield more turns but you might not reach the same max torque as on the first wind. I'm sure with all the rubber testing you've done you've seen this effect. Most indoor flyers don't have counters on their winders but I've never heard of one who didn't count turns.
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« Reply #112 on: August 16, 2010, 05:03:10 PM »

Count turns? I noticed two years ago that the counter on my Sidewinder wasn't working. I hadn't missed it, I've never missed it since; I trim to torque meter readings, note that which gives most performance and fly to that thereafter.
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Tapio Linkosalo
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« Reply #113 on: August 17, 2010, 01:12:00 AM »

Both [turns and torque] are important. Subsequent winds of the same motor will generally yield more turns but you might not reach the same max torque as on the first wind. I'm sure with all the rubber testing you've done you've seen this effect. Most indoor flyers don't have counters on their winders but I've never heard of one who didn't count turns.

Agreed. But still, torque is far more important than the turns. Actually, now after the champs I am in a middle of a thinking process of how using rubber in indoor and outdoor events differ. Outdoors, we find pretty fast and are happy if we can launch quickly, before the max torque starts to drop. Indoors, the winding takes much longer, and in the process we even let the motor stand for a while, to let the torque drop a little, to be able to pack in more turns. Sure enough, also for outdoor models people tend to stop the winding every now and then, and slightly pull and release the motor, definitely to make the knots fall in more evenly. But yet I feel that there is a fundamental difference in the way the motor is used, indoor and out, with the former giving more emphasis on the number of turns, and the latter to the overall energy. But as I said, my thinking process of this subject is only "in progress" at the moment.
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« Reply #114 on: August 17, 2010, 11:45:22 PM »

But as I said, my thinking process of this subject is only "in progress" at the moment.

My thinking has been "in progress" for a number of years now! I don't fly F1D but F1M has similar challenges and I think I understand F1M rubber requirements fairly well. The flying that mystifies me the most is in the classes with no rubber limits and no VP's. At USIC this year I was flying similar times to people using 60% or so of the rubber weight that I was using. My approach is almost always thick rubber, heavy rubber weight, low torque and slow climb. Others do the opposite on all counts and do well. It's a never ending puzzle to figure it all out.
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« Reply #115 on: August 18, 2010, 05:53:41 PM »

Thanks, guys. I've previously learned from at least three of you.

Counting only winder turns (and turns remaining upon landing) works for me and for the Science Olympiad students also. I always record torque before and after also.

I once argued on another forum, partially seriously, that winding is too important to leave to a mechanical device. Since I believe that counting winder turns helps me to concentrate, that is what I do and I always ignore the counter on the Wilder winder.

One indoor modeler who mentored Science Olympiad Wright Stuff students said that he taught his students to concentrate during winding by saying random numbers while they were winding for practice flights. I have told some students this, but have not actually spoken random numbers to test their concentration. Once one of them tried this on the other one who was winding. <Grin>

Fred Rash
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« Reply #116 on: August 19, 2010, 01:52:56 AM »

I once argued on another forum, partially seriously, that winding is too important to leave to a mechanical device. Since I believe that counting winder turns helps me to concentrate, that is what I do and I always ignore the counter on the Wilder winder.

Fred

I've found that the older I get the more I like my counter!
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« Reply #117 on: August 19, 2010, 09:36:49 AM »

What strikes me as interesting about this type of torque meter is that it may work in outdoor applications as well. I have seen one that used a dial indicator for the scale but that allowed for to much movement of the airplane to rotate about the axes. This with essentially no movement should work. I will probably never try it but would like to see someone else give it a go.
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« Reply #118 on: August 19, 2010, 10:28:36 AM »

Years ago Bob White had a stooge mounted torque meter (made by Bob Wilder I believe) that was mechanical. The drawback was that strong winds would rock the model and throw the readings off. Walt Ghio got around this by winding with the wings off. Today, with the advent of the 1/2 tube system of external winding a mechanical or electronic stooge mounted torque meter is far more practical. I did see Evgeny Gorban (Ukraine) using a mechanical version on his stooge at the Maxmen with good results. I watched him wind several times and could observe the entire torque build-up as he went along. Very cool! I've never really liked the winder mounted torque meters as you have to stop periodically to check the torque.

I must think about an outdoor electronic version for F1B/F1G.

Tony
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« Reply #119 on: August 19, 2010, 02:06:51 PM »

Here's the plan for the meter I'll start making next month. I had hoped to have the aluminum parts made by someone else but the cost was too high. Projected selling price is in the neighborhood of $50 but a final decision will depend on how much time it takes me to do all the cutting and drilling.

I think it will be important to have the winder hook the same vertical distance as the torque meter hook to keep from putting an eccentric load on the meter. On my Geauga winder I can move the mounting plate to a different location on the winder to make this happen. I don't know how this will affect users of other types of winders. If a winder mod won't do the job then it may require a block under the meter base to get the correct alignment.

In the meantime I've made some repairs to my original wood version and will take it to Lakehurst for the Labor Day weekend. I'm taking my old meters as backups.
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Alan Cohen
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« Reply #120 on: August 19, 2010, 03:11:58 PM »

I love this. I think this is one of the coolest innovations for indoor flying in a long time. Definitely falls into the category of "why didn't I think of that?!" Nice goin' Artie!!!
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gvwezel
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« Reply #121 on: August 19, 2010, 03:18:34 PM »

oke
hello i new in this topic oke in this world of f1d and i want to build a torque meter.
now i'm reading all about the digtial version so now i want to know how many grams of torque will F1D rubber gif?
also a want to now if you using al the time the same torquemeter than its oke thats is not kalibired?
hope all of you can help me

gertjan van the netherland starting f1d
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« Reply #122 on: August 19, 2010, 06:12:27 PM »

F1D motors will do around 40 gram-centimeters of torque.

Using an uncalibrated torque meter is fine unless you want to compare your information to that of someone else and then it is definitely not good.
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Art356A
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« Reply #123 on: August 20, 2010, 10:59:58 AM »

So to sum up, although that may be premature...

Fred says to pay no mind to the number of turns or the numerical value of the torque. Feedback thru the crank handle is all that matters.
Joshua says that counting every tenth turn is not sufficient. Alan's Minislick ran 3525 turns on her record flight. Can you really read the difference between 3522 and 3528 on a scale that divides into 500 parts? I've seen Joshua, after checking the turns and the torque, lay hands on the motor and palpate the knots before deciding if the model was ready for flight. What's that about and how would one quantify it? He laid hands on one of my motors once and the plane really flew nice after that.

Hepcat says that it's important to have a calibrated torque reading so we can communicate with our colleagues (Bill just reiterated that). That's what my contraption addresses. I think it's already an order of magnitude more accurate than the wire, tube & disc instruments, so I'm a little put off by the folks who are unnecessarily gilding the lily on the thrust bearing thing (although I can't fault Tapio's craftsmanship).

Tapio figures that there's a relationship between winds, torque, resting time, and how many flights on a motor that needs much more study than it's been given. Think Mass Launch... You've got all your numbers right on the button and then you have to wait for the last launcher to be ready as your torque drops. Is it part of the strategy to be the last launcher ready?

So... The more I learn the less I know. Just like life itself.

Meanwhile, I've knocked out a couple of more Frazer-Nash winders, although I haven't been able to find cheap counters like Peetee's. The pedometers I've found are way more than $12, but many of them will also tell you your heart rate and blood pressure. That can't be bad. There are two $18 low frequency counters in transit to me now which will just need to be slightly modified to make them resettable. At this point I'm approaching something duplicatible which I can draw plans for. There's still a lot of hand diddling involved which I want to eliminate if I can.

Art.
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« Reply #124 on: August 20, 2010, 11:47:34 AM »

For indoor, torque is most valuable because it keeps your model out of the ceiling. A very good thing indeed. Launch torque controls height, period. Turns are important if you really want to maximize duration by dialing in the motor length once you have an idea of the proper cross section necessary for your prop. Of course we don't want extra length which translates into more weight, less duration.

Ideally, when winding an indoor motor, you wind to just shy of max turns and then back off to the desired launch torque. That number could be 100 to 500 turns depending on the class of model. When the model lands it should also have turns left. In order to use the rubber energy efficiently, it has become common practice to center the flight portion of the motor run. In other words, if you back off 200 turns at launch, you want 200 turns left on the motor. If you are backing off 200 and have 500 left, shorten the motor. If you have 100 left, use a longer motor.
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