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Outdoor Free Flight Forum => P-30 Class Sport and Competition => Topic started by: goodeye on December 29, 2011, 04:27:28 PM



Title: FAI sidewinder vs Gizmo winder
Post by: goodeye on December 29, 2011, 04:27:28 PM
I am going to dabble again in rubber free flight after many years in R/C. Just for fun...no competition. I am currently building a P30 model with a BMJR Weight Rule model waiting in the wings. That will be the 'max' type of motor I could ever see me doing. I need a desent winder and I am going to purchase either the sidewinder with a turns counter (no T/M at least for now) or a Gizmo winder with counter and T/M. Both are in the $125 range which I'm ok with. I know most people say 'get a torque meter' but I don't want that to be the only reason I buy the GG winder. So I guess I'm looking for input as to which WINDER is best. A counter is a counter is a counter.

Help sway my decision...

Mark


Title: Re: FAI sidewinder vs Gizmo winder
Post by: danberry on December 29, 2011, 05:04:02 PM
The GG winder will wind faster. On the P30, that's a helpful thing.
The Weight Rule is a big plane. It's gonna use a lot of rubber which is where the Sidewinder might and I stress might handle the torque easier. I don't know how much torque the GG can handle.
The Weight Rule can easily use 12-16 strands of 1/8" rubber.


Title: Re: FAI sidewinder vs Gizmo winder
Post by: goodeye on December 30, 2011, 09:04:33 AM
The Gizmo T/M goes up to 24 oz. but I don't know what a typical torque is for a P30 model or a model such as the Weight Rule. All of my previous models have been peanut or walnut scale using the 'ol Sterling 5:1 winder (and that was 30 years ago)....


Title: Re: FAI sidewinder vs Gizmo winder
Post by: Tmat on December 30, 2011, 09:22:41 AM
P-30 torque is about 14 in/oz for a 6 strand 1/8" motor. 12 to 16 strands of 1/8" as Dan suggested will give 40 to 60 in/oz so the Gizmo winder is not enough for that application.

I'm one of those people that has a dedicated winder for different classes. So I have a Gizmo for P-30, A Russian winder for Coupe and a Ukrainian winder for F1B (Wakefield)!

Tmat
 :o ::)


Title: Re: FAI sidewinder vs Gizmo winder
Post by: goodeye on December 31, 2011, 06:40:46 PM
Took the plunge and purchased a Sidewinder with counter and handle extension for the higher torque capability. Will consider a T/M later....


Title: Re: FAI sidewinder vs Gizmo winder
Post by: NormF on December 31, 2011, 07:44:34 PM
You can make a simple torque meter from hobby shop items. See http://www.modelflight.com/torque.html

- Norm


Title: Re: FAI sidewinder vs Gizmo winder
Post by: craig h on January 01, 2012, 10:01:42 AM
I've always wanted to build a torque meter..but my problem not being math swave is how to calibrate it. On the Pensacola Free Flight Team web site under the articles index Herb Kothe has a nice drawing of his torque meter.


Title: Re: FAI sidewinder vs Gizmo winder
Post by: applehoney on January 01, 2012, 11:13:41 AM
Quote
how to calibrate it.

If just for your own use it doesn't matter how you calibrate it.  Don't worry about inch/ounces ...  mark it up in easy-to-use segments and just make a note of which number is the maximum  that you wind any given model too for maximum performance.    If it's ... say....  6.3, or 9.7   or whatever  - that's it!


Title: Re: FAI sidewinder vs Gizmo winder
Post by: PeeTee on January 01, 2012, 11:48:37 AM
Quote
If just for your own use it doesn't matter how you calibrate it.

I agree wholeheartedly with Jim on this one. I've made a number of simple torque meters over the years and for ease, calibrate mine in 20 degree segments which seems to be fine enough for my use. The important thing is to test each new box of rubber to get some idea of the number of turns per inch and torque it will take - I normally test 6" long motors to destruction (but have yet to do it deliberately with a 30+ strand F1B motor :o)


Title: Re: FAI sidewinder vs Gizmo winder
Post by: Tmat on January 01, 2012, 05:20:09 PM
There are articles on how to calibrate a torque meter that don't involve any math (well, some very simple arithmetic). The basic idea is to attach a wooden or metal rod to the torque meter output end and attach a known weight at a known distance from the end. For example, a 1 ounce weight at 1" from the center equals 1 in/oz. Perhaps someone can find the link to the article?
Also, there are sites that have simple online calculators that determine the estimated torque based on the torque wire size and length. And they also have a handy scale generator to allow you to print our your own scale.

Tony


Title: Re: FAI sidewinder vs Gizmo winder
Post by: Hepcat on January 01, 2012, 07:25:09 PM
I read replies #7 and #8 earlier today but I noticed they were by Applehoney and PeeTee who I regard as friends so I could not really respond and tell them how silly they were, so I didn’t.  Then, a few minutes later, I read Caley’s account on the ‘Went  Flyin’’ thread.

Caley had some new rubber and she was testing it and was kind enough to pass her results on to the rest of us.  She tried 6 strands of 1/8 in her P30 and using her Gizmo Geezer equipment got a torque figure of 16.  Then she tried 16 strands of 3/32 in her coupe and this time, using her Sidewinder equipment, she recorded a torque of 4.75.

Stuff friendship, I can keep silent no longer, that is why some of us like to have calibrated torque meters, so that we can communicate!

A Happy New Year to all and especially to Jim and Peter. ;)   

John



Title: Re: FAI sidewinder vs Gizmo winder
Post by: Art356A on January 01, 2012, 08:10:44 PM
It was a post from Hepcat a couple of years ago that said the same thing about communication that led me to make an apparatus to accurately calibrate my two disc-and-wire torquemeters. This took about a half hour. Once I got the first meter hooked up to it and applied some twist, I realized that the meter itself was totally redundant, as I could hook the rubber right onto the calibration device and have a nice digital readout.

Art.


Title: Re: FAI sidewinder vs Gizmo winder
Post by: applehoney on January 01, 2012, 10:55:54 PM
Quote
who I regard as friends so I could not really respond and tell them how silly they were

 ;D  John,  never hesitate for a moment!     ;D

A Happy New Year to you alao -    and to all     


Title: Re: FAI sidewinder vs Gizmo winder
Post by: Tmat on January 02, 2012, 02:41:53 AM
http://www.indoorduration.com/GoldenNugget104.htm
A link to a simple way to calibrate a torque meter.

You could also use a digital weigh scale to calibrate a torque meter as Art mentioned or even an accurate pull scale.

Another article with a bit more math: http://www.modelflight.com/torque.html



Tony


Title: Re: FAI sidewinder vs Gizmo winder
Post by: Art356A on January 02, 2012, 11:37:19 AM
Y'wanna see a torquemeter??  Here's a torquemeter!!!

19.5 inches long, with a table listing the twist characteristics of 4 different wire sizes from .032 to .063. with a bunch of Greek letters on it which Hepcat could understand but I don't. It's got two big husky (probably Mil Spec) precision ball bearings and a genuine Felsenthal protractor, which you can't hardly get no more.

Upon my tragic and untimely demise, it'll probably get passed on to Finn or somebody like that.

I'll stick with my digital for now, thank you very much.

 a.


Title: Re: FAI sidewinder vs Gizmo winder
Post by: PeeTee on January 02, 2012, 03:54:42 PM
Far be it for me to take umbrage at some gentle chiding from my long time flying chum Hepcat - and I'm not, in any way shape or form ;D

My comments related solely to outdoor rubber FF. Given the variability of rubber, not only from batch to batch, but also within the batch, plus the fact that calibration of the torque meter is I suspect highly unlikely to be up to NAMAS accreditation standards, I suggest that the overall variability is sufficient to make comparisons somewhat "iffy". I'd be most reluctant to advise someone on this basis, as I'd be mortified if it all ended in tears! :-[

I'd rather spend a little time trying to 'characterise' each new box of rubber, rather than calibrating a torquemeter. ;)

Peter


Title: Re: FAI sidewinder vs Gizmo winder
Post by: Tmat on January 02, 2012, 04:01:03 PM
Well Peetee, the rubber variability is imo irrelevant as to the topic of torque meter calibration. It is true that rubber does vary, but if you wish to wind to 30 in/oz, then that is what you wind to regardless of the vintage of rubber at hand (assuming that such a torque is possible).
And as for accuracy of the calibration, I think that it is easily possible to get sufficient accuracy with simple home made tools so Mil spec certification is not required. ;D

I'm with Hepcat on this one. Much easier to compare if everyone speaks the same "language".

Tmat


Title: Re: FAI sidewinder vs Gizmo winder
Post by: DerekMc on January 03, 2012, 12:41:48 AM
I would love seeing an article that spells out a simple way to calibrate a torque meter in in/oz.

Hepcat, please check your personal messages!


Title: Re: FAI sidewinder vs Gizmo winder
Post by: PeeTee on January 03, 2012, 02:41:14 PM
Ah Tmat, I suggest this is one where we agree to disagree :D I can understand that engineers such as you and Hepcat like to have something of the nature you describe, however I'm still of the view that the tolerance spread will be sufficiently great to undermine comparisons.

One of the links you kindly provided contained a formula where one of the figures was "Torsional Modulus of elasticity of music wire" :o This reminded me of a discussion awhile ago, either here or on another forum, talking about the variability of piano (music) wire. Some was described as "soft as butter", while other samples were as good as the stuff we used in our 'yoof'. I realise that calibration by hanging weights from a lever should take this into account, but it's time I'd rather spend building and/or flying ;D ;D

In the decade or so I've been flying rubber, I've never been asked "how many oz/inches of torque" I wind to. Occasionally with coupes I'm asked how many strands I'm using , and what sort of max turns - but that's it. I shall now return to my cuppa, content to be an oily rag, not an engineer ;)

Cheers

Peter


Title: Re: FAI sidewinder vs Gizmo winder
Post by: Tmat on January 03, 2012, 04:17:17 PM
Well Peter,

To each his own..... ;)

Tmat
-calibration for the nation....


Title: Re: FAI sidewinder vs Gizmo winder
Post by: danberry on January 03, 2012, 06:24:06 PM
I've been asked mant times about torque readings on my stuff.
Lotsa guys are amazed that I've no clue.
About a lot of things.......


Title: Re: FAI sidewinder vs Gizmo winder
Post by: Daithi on January 03, 2012, 07:17:49 PM
I've been asked mant times about torque readings on my stuff.
Lotsa guys are amazed that I've no clue.
About a lot of things.......

Theory is all very nice but before we all get bogged down in it, let's not forget that, according to all laws of aerodynamics, a bee has too high a wing-loading to be able to fly. Just as well for us honey addicts that bees know nothing about aerodynamics  :D ;D


Title: Re: FAI sidewinder vs Gizmo winder
Post by: Tmat on January 03, 2012, 08:16:07 PM
I know you meant it as fun, but the idea that a bumble cannot fly according to aerodynamics is a myth. In fact this was never stated by anyone studying insect flight but somehow became an accepted statement over the years. The statement has been used for several purposes over the years. One has been as a sort of pep talk such as "look at that bee, he doesn't know he's not supposed to be able to fly but he does anyways". "So think positive and you can do anything, even the impossible!".
The other purpose is to poke fun at scientists or engineers by showing how little they know or how foolish it is to even try to know things as they think that bees can't fly yet there goes one now!

The latter has always troubled me.

In fact, the mechanism that allows bees to develop enough lift to fly is now quite well understood and the discovery of these principles is an example of the kind of ingenuity that I see in many clever aeromodellers that aren't afraid to do a little bit of thinking now and again.

But I digress....  ;)

Tmat
-can't personally fly according to anyone, anywhere....


Title: Re: FAI sidewinder vs Gizmo winder
Post by: danberry on January 03, 2012, 09:19:55 PM
If I flew Coupe or Wake. I'd have a torque meter. I find it unnecessary for my P30 and Gollywock. Thermals help a LOT more than a torque meter could for those events.


Title: Re: FAI sidewinder vs Gizmo winder
Post by: Daithi on January 03, 2012, 09:48:07 PM
Actually all I really meant is theory is fine - but a torque meter is really only useful for compareison (to find the best for YOUR machine). To that end it doesn't matter about calibration in comparison with another meter - what does matter is you can compare the results on YOUR setup and pick the best one for YOU.

If your meter reads 'x' on one setup and 'x-5' or 'x+5' on another then you know which setup works best. What the value of 'x' will be on different meters is irrelevant really. Staring to toss numbers around isn't really useful in the long run - it won't improve the power output (or the climb or duration)


Title: Re: FAI sidewinder vs Gizmo winder
Post by: lincoln on April 29, 2012, 12:06:47 AM
Elasticity and strength are two different things!* The modulus of elasticity of steels is all very similar (so is the density). The strength can be all over the map. If someone says piano wire is "soft", they're talking about the strength, not the stiffness. Or else they're full of baloney. OTOH, you need to know the DIAMETER of the wire to a pretty close tolerance if you want to calculate the stiffness of the wire correctly. I forget if it's the fourth power of the diameter or what.

To calibrate your meter, all you need is a lever and a weight. If you have a 10 inch lever and a one ounce weight, then, surprise surprise, that's 10 inch ounces!

*Think peanut brittle vs. polyethylene (as in a plastic milk bottle), for instance.  Or fiberglass vs carbon fiber, which are both of similar strength, but the carbon is maybe 3 or 4 times stiffer. Or a cookie (the kind you eat) vs. a piece of gristle.
snip
One of the links you kindly provided contained a formula where one of the figures was "Torsional Modulus of elasticity of music wire" :o This reminded me of a discussion awhile ago, either here or on another forum, talking about the variability of piano (music) wire. Some was described as "soft as butter", while other samples were as good as the stuff we used in our 'yoof'. I realise that calibration by hanging weights from a lever should take this into account, but it's time I'd rather spend building and/or flying ;D ;D

snip
Cheers

Peter


Title: Re: FAI sidewinder vs Gizmo winder
Post by: lincoln on April 29, 2012, 12:09:51 AM
P.S. I made a winder out of an old electric drill, and a counter out of a calculator. The winder is something like 8.3 to 1, so the calculator is a good way to go. Wired a reed switch to the equals key and enter 8.3+. Or is it +8.3? Works well. The drill is very robust, and there's no doubt which one is mine. Ergonomics could be better, probably needs a handle.