You did, and I apologise if I have given you offence. None intended.
I did get a little warm about the “wars and rumours of wars” that your search revealed, and at the implications they might have.
If there was any justice the same authorities might like to consider Nicads and Nimhs for bans in the same way - there have been many hundreds, if not thousands, of exploding rechargables. All electric flyers, drivers and boaters have heard of and possibly seen the effect of a blowing nicad.
Non taken Andrew
Yes I agree and have seen a NiCads blow once under a high discharge situation. Having used and abused NiCads and Nimhs, for many years in electric flight I see the key difference as being the fire element. A NiCad explosion is bad if you are in the line of fire as it were, then it is over. The LiPoly is more akin to an incenduary device than a bomb when things go wrong. At the last two electric fly-in’s I ran at our club here there was a bucket of high concentrate salt water available. I understand that will stop the reaction.
Graham, I would reiterate that one of the recorded LiPo fires burned on underwater after being dropped into a bucket of salt water (see earlier post).
Reading these last two pages of posts, you all seem to be in agreement that throwaways are better than rechargeable and that an inexpensive boat will need expensive batteries to be competitive (so much for those Boy Scouts). And, removing the AA restriction will will lead to Brett developing super-light boats and putting the nail in the coffin of the class that he was the first to promote. (Just a note here, the data on super light designs is empirical and developed from observing a free-sailing Footy that didn’t tack. Pure “foot” speed is great for time trials but only one factor in making a boat competitive in fleet racing.) Nothin’ like them scare tactics!
“I see”, said the blind man as he fell into the ditch.
Graham, I would reiterate that one of the recorded LiPo fires burned on underwater after being dropped into a bucket of salt water (see earlier post).
Reading these last two pages of posts, you all seem to be in agreement that throwaways are better than rechargeables and that an inexpensive boat will need expensive batteries to be competitive (so much for those Boy Scouts). And, removing the AA restriction will lead to Brett developing super-light boats, putting the nail in the coffin of the class that he was the first to promote. (Just a note here, the data on super light designs is empirical and developed from observing a free-sailing Footy that didn’t tack. Pure “foot” speed is great for time trials but only one factor in making a boat competitive in fleet racing. Earl believes, as do I, that there is a point where lighter weight ceases to contribute to speed and handling. As much as we wish to the contrary, we sail keel boats not dinghies.) Nothin’ like them scare tactics though!
“I see”, said the blind man as he fell into the ditch.
Sorry Niel I didn’t realise you had said ‘salt’ water too.
I have used rechargeables more than throw away in fact, so I am in that camp. Throw away was convenient on my travels that was all.
I agree with you both about super light boats too, the theory has yet to be proved there. I think I have banged that drum before.
If push comes to shove my position on batteries is…
1). Stay with the 4xAA but not until they are hard to find should that happen. I like the challenge.
2). Allow any battery type/number except LiPoly… but how to do that? Maybe simply state… no LiPoly cells.
Remember hat even the lightest Footy is quite heavt in proportion compared with most boats. Even Moonshadow has a displacement/length ratio of 292 compared with (say) 200 of a typical 12 m or 120 of an IOM.
In a Footy context ‘unltalight’ is coming into he ‘sails properly’ band at the heavy end, not moving out of it at the light end!
Not sure how this will be received by the profound and respected thinkers round the world:
If we could find a couple of boats that are (essentially) the same (507s or Razors) it would be interesting and possibly instructive to run one with 4 AAs and the other with 4AAA and see the difference, if any.
I know that this doesn’t sort the answer to the discussion but it might:
[ul]
[li]Give a view on the relative fun coefficient
[/li][li]Indicate what effect a change might have
[/li][li]Reduce the notorious sensitivity of Footies*
[/li][/ul]
Just a working engineers thought
andrew
*Which may be a contributory reason for the extensive absence of boy scouts, (or even humans younger than 60) from the ranks of the class
It may be worth pointing out that the safety issues when using, rather than charging, LiPo and Lithium ion cells are when they are being used for motive power and putting out currents of sometimes more than 100 amps, as would be the case in straight line hydroplanes.
The current draw for just an onboard radio and two small servos sees the current down to within the original design parameters of these cells and their use becomes no more dangerous than walking around with a mobile phone or a digital camera in your pocket.
Beating a hasty withdrawal from foreign lands chased by an ogre:lol:
I’m under 60 andrew! lol. As i have noted earlier, i would like to see the AA rule go; the boats would, i think, become less tender and more fun both to design and sail. but, that is just me. as for the LiPo issue, i think it is important to note a couple of things:
Lipos would
not be required. If one is not comfortable having a bomb in the bilge of their boat, then by all means, don’t put one there.
as noted before, not be under particularly high strain. while sailing a footy, i think it would be safe to conclude that at the highest current-draw portion of the sail - sheeting in and steering to bear up around a bottom mark - that the amount of current required would not even come close to the power that is demanded by a FE hydro, or a 3D acrobat. which is where the things have been known to burn spontaneously.
not be in a position to be a danger. i personally have crashed a LiPo-powered aircraft out of the sky on two occasions. once was in a gust of wind with a trainer, and once was while trying to do a four point roll in a little foamy. although i ruptured the cell, the battery did not cook off! much as the labels warn of eminent death upon use, LiPos can take a beating. (within reason) Unless someone comes up with a 100mph footy, there is not going to be a time when there is a hard enough impact to set off a battery.
All that said, i am not even sure that LiPos would prove to be the best power source to use. there are a million other battery types out there, it may turn out that the worlds fastest footy runs energizer watch batteries! who knows, all we have to do is try.
A few more random thoughts.
A change to allowing AAA will not help much.default battery then becomes the throwaway Lithium AAA at about 32g for 4. Sailing with these batteries is more expensive than the AA Lithium throwaway cell. The better sailors will not use the rechargable AAA cell as there is a weight penalty just like the current rule.
Current Footy “powerplants” ( r/c system complete) account for 20 - 35% of the total weight of our models.
IOM “powerplants” account for less than 6% of total weight.
So maybe opening up the rule completly is the way to go??
I don’t belive we would be able to restrict battery chemistries…except if some are illegal.
As a matter of interest we have here several small airplane models bought at a local toystore,complete with a tiny LiPo cell and charger,my 12 and 8 year olds where able to buy these models over the counter,The battery is open on the side of the plane fusalage.
My bet is that if they land these planes on wet grass then the battery will be more exposed to moisture than Dads well built Footy models which keep water out rather well and can do it even better if a battery like this was to be stored inside it.
I hooked one of these tiny 5 gram cells up to my current r/c gear and had a play on the bench.The cell behaved well and powered my “bench footy” for quite some time.
Weight of this r/c system is now at a spritely 25g complete. My tests show I could sail for an hour or more on this cell.
I reckon I am more at risk crossing the road at lunchtime than putting this cell into my boat and going sailing?am I wrong??
Lightweight batteries won’t just help those who seek to builder lighter boats( I like Niel and others belive there will be a lightness limit)Boats of 500g displacment will benifit greatly from such light weight cells.
Of course though removing battery restrictions will enable lighter boats to be built and sailed,compettion will prove if they are better or not.
The report of the last Guilford Footy racing is interesting,the event was won by a 600g boat and a 330g boat also won a heat,700g boats also featured in the placings.There is no clear indication of best displacment in this class yet.
Pic of a similar cell
measures 36x20x5.5 mm and weighs 6.55 grams including wires
Will it really?? maybe I would have a crack at a light boat who knows? I sure as heck won’t be the only one to try…You started this thread with the idea of removing restrictions then charge me with killing the class because of it!!
Lets go back to page one where you say ballast ratios will increase for all,true enough…I said that the ratios will increase more for the better builders which of course we can show mathmatically,no response on that one.
The fact is that removing battery restrictions will favour builders capable of building lighter boats than the rest.
Most important thing to remember is that simple rules create complex boats and complex rules can be used to define simple boats.
No rule should be regarded or revered to be “fair for all” nor should it,it is the impossible dream of the rule maker.
With such a small boat, where conditions can make a huge difference in performance I wonder if there is such a thing as a best displacement for this class.
I think the difference between a small pond and light wind and a pond large enough to allow a chop to build in a still fairly moderate wind creates a range of conditions that are greater in proportion than that faced by larger boats. (or do we stick to the first type pond exclusively?)
Still no experience sailing an actual footy, but I do recall fifty years of full sized sailing and my friend Alex’s twenty-five inch Braine gear equipped boat braving the waves off City Island, NY while we tried to keep up in a small rowing pram. A great learning experience, we use an outboard after that!
Here we are worrying about the cost of a different battery driving some people out of footydom, but the rules are very open, and I could stick a small gyro in to help hold the course (I already have one in a camera plane that I fly) and reduce skipper induced oscillations to a probably noticable degree. Nothing seems to be in the rules to prevent that.
How about a clinometer? It’s a relatively inexpensive robotic part, which when coupled with a stamp computer could ease the sheets to maintain an optimum angle of heel in gusts.
I can envision a simple pitot to measure water speed, how about an algorhythm in that stamp computer (or pic) to tweak the sail trim, looking for an optimum rather than a trifocal wearing skipper trying to see what sail trim is doing to his boat from a hundred yards away.
None of the above is amazingly difficult to do, seems to be within the rules, can be made very light weight and is quite affordable to some, but not all.
l think worrying about the cost of batteries is minor compared to the cost of sophisticated electronics (starting with a $30 gyro) that may be able to significantly improve the speed of a boat around a course.
Just blue sky daydreaming, but wait a couple of years. When I first stuck a video camera in my airplane I thought it was a big deal, now people fly with video that includes on screen display of telemetry and GPS data. The stuff weighs ounces now and gets smaller every day as specialized chips are developed.
A brief answer to Brett, my last post was supposed to read as a sarcastic summery of the discussion so far. If it wasn’t interpreted that way then the fault was my poor prose, no offense or real accusations intended, to Brett or anyone else.
To Pete Schug, thats my way of thinking. The Footy class should be a leader in adapting innovative technology. We are a new class for which small components are are a priority. We should be the ones to try out new electronic equipment that will eventually filter down to those big-ass model sailboats!
The change to the battery rule would not necessarily mean switching to LiPo cells. What it would mean is that there would be choice as to what powers your r/c. Those of you who want to stay with AA rechargeables can. Those of you who want to try new battery types as they become available could if the rule were changed. If you want to try a small solar panel trickle charging a really small battery or capacitor you could try that too.
Eventually, the Footy class will probably find its archetypal configuration and optimum displacement just as the M class has done. I think that freeing our class from excessive onboard weight will help us find that displacement figure. Once this average is determined then we can focus on providing the information and building tips so the kitchen table builder can approach the ideal weight with a good disp./ballast ratio.
My guess is that if this optimum displacement exists then it is probably pretty close to the 450g to 500g weights that we currently sail at. In that case then the improvement will come as increased righting moment (sail carrying ability or “stiffness”). That would be good for the performance of the boats in general and a boost to the Footy image.
I was in a store today called “Dollarama” in London, Ont., and saw a Lithium battery by Sunbeam for $1.00. It was labelled 3V but there was no amp-hrs info. The battery was about half the size of one AA, and probably weighed less than half of an AA, so two batteries at 6V would probably power a Footy for at least a days sailing.
The thought just boggles the mind–the whole electronic package would be appallingly light.
Yours, for AA retention
Rod
All the racers show up with receipts for their batteries, demonstrate that the battery works for an hour and the one who paid the least wins. No need to even get the boat wet.
