SEN 2146
Table of Contents – SEN 2146
- Fab Feb dates 2017
- all wound up part 2,3,4……
Fab Feb dates for 2017
Yes people are booking already ..
Kiwi 11-12 Feb, Ladies Tea party 14 Feb NA 15 Feb & MM 17-19 Feb – 20 Feb is Presidents day public holiday and reserve day.
details later
Subject to FAI calendar approval
Winding – 1
From: John Clapp
I agree with Bill Shailor. But let anyone wind by hand or with an instrumented electric winder.
I feel that there is nothing that beats ” seat of the pants” winding. I coach and am CD for many rubber powered Science Olympiad events and see an occasional electric winder and just shake
my head. Many of my team members are girls and they quickly learn to achieve max turns by the feel of hand winding.
My thoughts
John Clapp
[John is the former owner of FAI Model Supply, F1B sportsman and has been very active in helping on the Science Olympics program in the USA, that includes a very successful indoor rubber powered event]
winding – 2
From: Carrol Allen
For several years I have used a a set of electronic strain gagues to measure
torque and pull tension. These are displayed as numbers on the stooge.
Robert Morris and myself are publishing a paper in the digest called
constant energy winding. One needs to know stretch distance, pull and
torque. With a large ball screw, winding motor and knowing tension and
torque one could build a quite nice winding machine. Would this be allowed
under the present rules for F1-B where the competter is required to wind his
own motor?
I have recently added a third meter to my stooge that tells me if I am
coming in too soon of not quick enough. It seems to work quite well as I get
a very even row of knots at the end of the wind.
Carrol Allen
Question – Carrol – how do you measure the distance for the third dial, and do you just give the distance or do ou say where you should be in relation to the start point of an individual motor ?
Winding – 3
From Peter Brown
Hi Roger
In response to the debate about rubber winding my thoughts are.
Putting aside the problems of carrying even more kit to the flying field
For sure a more elaborate and successful method of winding could be developed using electric motors, torque sensors , strain gauges and the like, which could ‘feel’ the rubber better than any human.
However would such a device not contravene the rules which state that the rubber must be wound by the flyer or does pressing the ‘go’ button on a computer driven machine count as winding…………
I am not sure how that would go down with the rule makers.
Peter Brown
[Peter Brown is an F1B sportsman and skilled machinist who with his electronics friend Leo Bodnar built the rubber tester seen on you tube and referenced by CHE]
Question – it seems there are two issues- is an electric winder OK and can you have the extra sensors that provide automatic feed back ? On the first point ‘case law’ indicates the winder is OK because a number of people have used them in major event with not protest.
People certain have extra sensors – see Carrol Allen’s particle above and many people use torque meters and counters but none automate the process.
Winding – 4 From FB
Michael Woodhouse: Chris sorry about that. Start again! A simple observation for you as a glider flyer you sense and feel the lift as you tow. A rubber flyer senses and feels the motor as he winds.
Bernard Guest: Agree that feel is important … We basically have a feedback loop on our brains as we wind that helps us estimate with fair accuracy when the rubber is close to full turns. A bit of clever programming with a digital torque meter should be able to manage the same loop but then you would want the human out of the picture so that the noise in the system is minimized… At which point it ceases to be a human sport. Winding the rubber is an important component to the sport just like running with the f1a on the line is an important part of the sport.
Chris Edge: Good comments. Wrt to towline, if it was legal for a robot to fly in contests I suspect that it would use algorithms that would enable it to find lift more efficiently than a human to be honest. I agree that winding the rubber is an important part of the gig, just proposing that maybe you could do it better with a non human system. CHE
Derek McGuckin: The real reason is because Andruikov doesn’t …. yet 🙂
Beto Castrucci: Change the rubber to electric motor!!!! 😀 😀 😀 😀 😀 😀 😀 😀
Tony Mathews: And use a rubber band to start it Beto? Hehe?
Kevin Lamers: What if during manual winding the energy put into the rubber is tracked (turns*torque) and you just wind to a certain minimum amount of energy. Assuming constant hysteresis, this way you will always put the maximum energy in the rubber. In case the motor breaks before this energy level, the rubber was rubbish or the winding process was not done correctly so you start over.
Chris Edge: Well that’s what I was thinking but perhaps you could link it back to the rubber testing as well to get almost the best wind for each motor based on the test data. CHE
Michael Woodhouse: Test and application differ that’s where manual intervention takes place.
Beto Castrucci: Weather, temperature mainly, interfere .
Omri Sirkis: I was playing with the idea kevin described . Using the standard hand winder but with digital torque metering and turns counting . A small processor will calculate the total energy in the motor on real time . This can be powered by an electric motor also.but CHE, you fail to understand one thing…sportsmen who fly F1B have very conservative minds.we are using rubber , winding it by hand. And in some cases clockwork timers…
Ismail Sarioglu: Time to time, ( indeed most of the time, ) time is the essance. I would rather go in the good weather, with a 90% energy motor, rather then bust it and go 5 min. later in turbulance.
…………….
Roger Morrell