A weighty situation

[Bob Hunt]

It is time to revisit the discussion about the rule governing the weighing of CL Stunt models as it now exists in the AMA rule book, I fully realize that this may soon - or eventually - get booted over to the rules discussion forum here. But, I wanted to let everyone know how I feel about the current rules and give them a chance to voice their opinions here on the main forum. Not everyone visits the rules forum here because not everyone is interested in competition. The rules regarding weighing models affects everyone here in some manner, so everyone here should be aware of what’s going on.

As the rules read now, a CL Stunt model with a glow engine gets weighed without the fuel on board, while an electric powered model must be weighed with the battery on board. There is a terrible inequity here, and a huge safety issue. Glow models can add as much as 7 to 8 ounces of fuel after the weigh in process and their takeoff weight goes up that much because a fluid ounce of fuel weighs nominally an ounce. So, a glow model that weighs in at 64 ounces gets to legally fly on thinner lines than an electric model that weighs in at 65 ounces (the line size break is 64 ounces…), even though it may weigh as much as 72 ounces or more at takeoff! This is just wrong, it's unsafe, and it needs to be changed.

If the rule regarding airplane weight versus line diameter is meant for safety, how is it safer to allow a glow model to become airborne at a higher weight than an electric model, while also allowing it to fly on thinner lines?

This is not a new discussion, but it is one that needs to be resolved for the sake of safety and fairness. I intend to bring this up with the CLACB as a potential emergency rule change item. There is no valid argument that I can see to allow a glow model to exceed the weight limits for a given line size at takeoff. Sure, the fuel burns off, and hence the weight burns off, but at takeoff many glow models are exceeding the 64 ounce line size break point; sometimes by a lot!

The rub is how do we then enforce this rule. Will we have to ask the flier to present his or her model for weigh-in with a full tank of fuel? Will we work on an honor basis and allow the flier to just tell the weigh in person how big the tank is and then the weight of the fuel can be calculated and added? I’m certain that some of you will come up with brilliant ideas to answer this question. I’m equally certain that there will be many who will vehemently oppose what I am proposing. My question to them would be, “Are you opposed to this because my math or my reasoning about safety an fairness isn’t correct, or are you just trying to keep your competition advantage?” 

Thanks - Bob Hunt

[peabody]

All great points Bob.
My belief is that any lessening of weight requirements will not "fly" with the Academy. The powers that be there perceive that reducing pull tests will result in safety issues......
You "honor system" of tank size sounds good, but may be easily circumvented by someone on the margin of being able to use smaller lines.
I would wager that planes around the weight break for line size (64 ounces. I believe) consume more than 4 ounces of fuel. The next line size break is 90 ounces, I believe.
Rather than argue the economy of a belchfire .79, adding 4 four ounces to the weight of IC contenders might do the trick?

Whatever is done (if anything), I hope that there can be full agreement prior to involving the AMA, as I feel that they would only compound the problem (if there is one).

Good thoughts!

[Brett Buck]

Hi Rich:

Nowhere in my missive did I propose any lessening of weight requirements. I only proposed that all models in the Stunt event be weighed at takeoff weight. And, I've already discussed this at length with Tony Stillman at AMA. He is in total agreement that the models should all be weighed at takeoff weight. He suggested that I first go through proper chain of command channels and propose this as an emergency rule change proposal to the CLACB (Control Line Aerobatics Contest Board). He said if that fails to yield fruit, then I should make the emergency rule change proposal to the AMA Safety Committee and he would back me up.

Thanks for your thoughts. - Bob

     If all you are going to do is raise the weight for IC engines, I don't see why it is necessary or what it accomplishes, either for safety or for competitive balance. It's not like people are building their bellcrank mounts to make, say, a 41-lb pull test but not a 44-lb pull test (just using my own airplane as an example). And, for the most part, most pull test devices are probably not accurate to better than about 5 lb.

     As far as line sizes go, you get no advantage to using .015 vs .018 if you are anywhere close to the break point; you are driven to use .018s for precision reasons alone. I won the NATs using what would now be considered "oversize" lines, that is, .018 on a 62 ounce airplane.

   In any case, this certainly doesn't meet the criteria for an emergency rule change. This is more-or-less the same situation we have had for 50-60 years, since pull tests were required, and the current line size and break points were designed based on the current situation, and no one thinks the current situation is in any way unsafe or even marginal. In fact, it has a huge margin, roughly 4x, which hardly changes if you add 6 ounces to everyone's airplane (again, this if FAR inside the usual tolerances of weighing and testing).

   And how far are you going to take this? Fill the tank and dribble fuel everywhere? Just take someone's word for it? What if someone says they run 6.5 ounces, and it's really 7.2? Is that  really going to make a difference where people are weighing airplanes with fish scales to +-4 ounces, or having their postal scale change by 10% due to temperature effects on a load cell?

     The only thing I see this accomplishing is to slightly annoy IC fliers with an irrelevant pull test change, mostly to make electric fliers to feel better about the ridiculous "weigh-in pissing contest" that a few engage in, based on the premise that how heavy your airplane is somehow says something about one's skills as a builder (which is doesn't),  or try to impress others with the half an ounce you saved so you improved performance (which means nothing).

    I really don't care about this change, add 4 lb to my pull test, what difference does it make? I strongly suggest this stems from pissing contest aspect, and some electric fliers are embarrassed about reporting 73 ounces while IC fliers report 64, because there are still some nitwits who think their airplane weight is some sort of measure of their building skills. It's not changing the competition any and no one is going to build their airplanes any differently. It makes no difference at all for safety, since this is far inside the existing tolerances and far inside the existing margins

    No one (or only a few people) will end up on different size lines, and those who are forced from .015 to .018 will almost certainly be better off for it, even if they don't know it now.

 Brett     

[Randy Cuberly]

I agree with what Brett said here!  Also the Term "line break point", seems very arbitrary to me since there is actually some safety margin included in that number!

I currently have a IC airplane that weighs 63 ounces on my electronic scale at home, 63 ounces on a scale at the post office and 63 ounces on a scale at my butchers shop.  When I take it to a contest both here and in CA and they weigh it on one of their funky fish scale it always seems to weigh 64 to 65 ounces.
While it's really not problematic for me because I would fly it on .018 lines anyway for the difference in line stretch it does show the silliness in being so worried about a couple of ounces of weight at a supposed "line break point".
If we are really so worried about this issue we should demand the use of certified scales for weighing!

 

Randy Cuberly

[Perry Rose]

I'm showing up with an Evo .60 powered 63 ounce plane and a 4 ounce Du-Bro plastic tank. What kind of static can I expect?

[Brett Buck]

Hi Brett:

You and I don't often disagree these days, and I'm certainly not trying to "pick a fight." Your thoughts are good ones, but consider the legal ramifications of the current AMA rules in respect to weight of models. Should a glow engine model that weighs in at, say, 63 ounces without fuel on board then have fuel added to exceed the weight limits for .012 solids or .015 cables, and then have an accident just after takeoff... Well, if a lawyer got hold of this there could be serious repercussions.   

      I am not sure how you get that, since the pull test was defined (since I helped defined it) based on the empty weight of an IC airplane and has effectively been in use for something over half a century. And in any case, the difference in weight is in the noise of the measurement errors. I did an eyeball tolerance stackup analysis and it's on the order of 5 lbs or so when you get to the test. That includes the likely bias and scale factor errors in the weighing scale, the bias and scale factor errors of the range of pull test devices, and a guess at the tolerance on the line strength. With everything right down the middle of the error bars, there is roughly a 4x safety factor. It goes down to about 3x when you consider all the errors. That's the difference between a 30 and a 40 lb pull test. The only way to improve that is to start specifying the required performance of the scale and the pull test device. Even without improving the system, you have a 1.5x factor of safety even after a line break and you are flying on one line. That is a typical aerospace specification for structural margin in weight-critical systems.   None of this was an accident.

I also don't agree with you about the performance difference between .015 cables and .018 cables. I once said that if I were compelled to have to fly on .018 cables that I would just opt to not fly at all. That's how much of an advantage I feel there is with the thinner lines. Personal preference I guess. I never flew with an abundance of line tension; just enough to do the job. I guess if I had set up my planes to pull harder then I might see the problems you have described.  But, this rule proposal is not about that... It's about safety and insuring that we don't have legal action taken against us due to a model flying on the thinner lines in an overweight condition.

     Since you didn't quote the analysis or the margins you used in your analysis, I can't assess what you assessed. It's not a legal problem, or if it is, it's the same legal problem we have had for more than half a century. If anything, weighing the electric models with the 10x the battery weight included reduces the legal exposure.

Tony Stillman at AMA agrees with me on this point...

     Tony Stillman was not involved when the current 10G and line size break points were established, and I am not sure what his background in aerospace engineering of life-critical systems might be. So, aside from the fact that you went to him before mentioning this supposed problem to the rest of us and getting in your shot first, I am not sure how that affects the engineering issue involved.

   The point about .015 vs .018 performance is a reasonable one (although I think you are wrong), but your change doesn't change it for electric, only for IC, which seems to reveal the real motivation - to "even up the playing field" for electric. OK, swell, but as far as I can tell, almost everyone that is potentially affected is *already using .018 lines*, so it changes absolutely nothing in regard.

    If someone competitive wants to fly their PA75 airplane on .015 lines, I will happily supply them for free and even hook them up for them, free of charge. Hey, Derek, buddy, do I have a deal for you...

Hey, old buddy, let's not let this become anything more than it is. I highly respect you and your thoughts. All I ask is the same.

   No problem here, I am willing to be entirely frank with you because you *do* listen and respond, and generally know what you are talking about. But I don't think this change has anything to do with "safety" or legal exposure, because it has no consequential effect on either. I think it has to do with the feeling of it being "unfair" to have to pull electric 4 lb more than IC, and whatever that stems from.

   I don't significantly object to this almost entirely irrelevant change (it changes the pull test by about 4 lbs for IC models) but I do somewhat object to the characterization as a "safety" issue because a lot of actual work and electrons were expended coming up with the current chart based on full-scale aerospace standards, and a consideration of all the factors, and I object strenuously to characterize it as a legal problem. Show your work, let's see the numbers and see the tolerance stackup analysis. 

    And anticipating the next argument, no, it is not a good idea to "always improve safety" because the best way to improve safety is to shut down the event. You trade off safety margins for performance, and some trades are not sensible. It would be safer, for instance, to require 1/32" 19-strand wire rope, and a 40G pull test. You would have a 8x margin instead of 2x, every single current airplane would be destroyed attempting the 160 lb pull test (although my bellcrank handled 205 for a while) but I am pretty sure you won't have a lot of line-break-induced flyways, think how safe we will all be. 

    Brett

[Randy Cuberly]

Again, I agree with Brett. 

I do however agree that from a fairness point of view it does seem unfair to have a different standard of takeoff weight for electrics and IC aircraft.

I would propose that the rules change to include the weight of the fuel at take off based on the quantity of fuel permitted by the onboard tank.

I have never thought it was fair to base pull tests on different "takeoff weights" between Electrics and IC aircraft.

The pull generated is based on their respective flight weights not their fuel types!

I definitely do not think there is anything to be gained by potentially creating problems over perceived "safety issues" which probably do not exist based on past history of our event!

Rather than just increasing the pull test requirement for IC aircraft perhaps a different formulation should be explored for both IC and Electric to determine a common requirement.  If a lower requirement is adequate for IC aircraft it is likely also adequate for Electric aircraft based on past experience with IC aircraft.

Randy Cuberly

[Dave_Trible]

I doubt there is any concern about how we pull IC airplanes but in order to have more parity perhaps the electrics could use a sort of K factor- and I’ve done no math- but something like .9 X what the IC would pull.  Just an idea.

Dave

[Steve Fitton]

Bob, what were you using on the Saturns, were those lines solids or stranded?

[Gerald Arana]

Take this for what it's worth from a mid pack advanced flyer. I'm new to the full size stunters this year and I've been flying an ARF electric on .018" that's 69 ounces. It pulls pretty good and just seat of the pants experience of 57 years of flying I wouldn't want to fly this thing on .015". Now think of a PA 75 or other big glow engine on a run away flight at 69oz and I can see the danger.


Motorman

Hi Motorman,

I too am a middle (lower) of the pack advanced flyer. My (best) stunter weighs 64 oz's with a VF 46 on a pipe and I feel the .018's are best for me. But that's just me. Someone else might argue that I could fly on .015....... Not me!

Brett & Bobby, I think you guys are having too much fun with this non problem! 

See you in Woodland Brett, Jerry

[Eric Viglione]

Where was the line of people with IC planes flying away on broken lines and wanting to weight them with fuel onboard before E-Power came along? Oh, there weren't any, and there still aren't. Line maint is still the key, and pull tests aren't max, which will do more long term damage than good, they are only enough to weed out line's about to fail.

Let's not re-write history folks. I "think" part of the issue was at the inception of E-Power, that most of the viable batteries available for stunt weighed over 1Lb (even Brodak shipped the original Electric Clown with a  gigantic 3200 or 3600 battery that was big enough to haul a Strega nowadays) As battery weights come down, this is becoming more and more of a non-issue.

I'm not inclined to like compromises (since they make both sides of an argument unhappy) but since the current IC rules were written with a safety margin for a typical max 8 Oz of fuel which is ~7.2 oz (at ~.9 oz per fluid oz) Then I'd think a more sensible compromise would be to only add the difference of a battery that weights more than 7.2 Oz  (.9 x 8.0 ) from the weight of a competitors battery for E-Power planes. 

EricV

[RandySmith]

Much ado about  nothing,  best to  leave it alone and  not  give  lawyers  any fodder
 and  by the way   I am like  most everyone, I use  018  on a 59 ounce stuntship,  a 60 size  piped  stuntship  is  spongy feeling  on  015s ,
so I am not saying this  for the advantage of using  015s, that is  a  non issue  for  me  and most people flying, others use  014 solids

Randy

[Chris Cox]

I have not personally witnessed a line failure in flight of a stunt model that has already passed a pull test, other than perhaps a model that free flighted across the circle due to a wind gust, and then snapped a line at the opposite end.

Maybe a potential remedy could incorporate two amendments.  One - Increase the maximum model weight to 71 ounces (ie. 64 + 7 = 71) at which point the line size requirement increases to .018” minimum (it seems to have been working so far) and;  Two - IC flyers self declare their fuel load at weigh in.  Yeah, some may report a less than actual fuel requirement, but with the added line stretch of a model over 71 ounces, .015” lines would be more a detriment than an advantage, in my humble opinion.

Be nice, I’m Canadian... (and we now utilize AMA rules...)

[Frank Imbriaco]

Electric powered ships are definitely being placed at a disadvantage with having to be weighed with their fuel source in place.
 Impact to the lines - solid "fuel" battery vs. IC wet ?
Zero difference on takeoff and through at least the first quarter of the tank.
Now that's apples to apples.

[Eric Viglione]

Respectfully, Eric, I was in at near the ground floor of competitive electric stunt. None of my batteries even back then (4,000 mAh packs) weighed anywhere near 1 pound! They were around 10 ounces if memory serves. But that is not the issue I'm "discussing" here. The issue is airborne weight versus weigh-in-room floor weight. A 64 ounce electric model will still be 64 ounces when it becomes airborne; a glow model that weighed in at 64 ounces will weigh significantly more wheat becomes airborne. There is no "fuel" added after the weigh in process in electric; why should glow models be allowed to fly at a weight that is much higher and on thinner lines? No one has answered that question adequately for me. There seems to be a lot of smoke (please pardon the obvious glow power pun...) coming from one camp without addressing my question.

I fully expected a "lively" discussion on this issue, but I certainly don't want it to degrade into a mud slinging contest. Can't we just simply agree to weigh the models at takeoff weight, do the pull test and get on with our fun?

Again, respectfully - Bob

But Bob, your building a straw man that says there is a crisis that needs solving for IC... when there is none, and IC has nearly a century of data under it's belt to prove it. You are asking IC to take a hit to accommodate the new kid on the block... safety margins are built into the current rules to accommodate your straw man and why is that YOU cannot just bend?... Why is it the other guys? Because it is YOU that is asking? I have the highest respect for your accomplishments and sweat equity you have put into the event over the years, but it seems like you think it's your way or the highway, and expected a bunch of accolades to your current request. Well, I'm here to tell ya, it's not a great idea, no matter who suggested it.

AND... I stand by my comments on the early days of E-Power... maybe you had access to cutting edge product and were ahead of the curve, but down in the trenches where I was helping trim/observing "regular" people with their early E-power setups, 15-17 oz was NOT uncommon battery weight to power a 60 size ship in the early days, and great gains have been made since then to reduce that. Eventually, I foresee a time when E-power batteries will be lighter than glow fuel, heck, they are almost there now.

I still stand by my comment that this is a non-event, and if anything, do an offset equation based on the safety margin already built into glow and do an additive for the difference to E-Power depending on battery weight if you MUST do something, not the other way around and have fuel dripping in the 180 building... But that said, I strongly feel that anything you do to raise this with the AMA will have a higher potential to hurt the event in the long run than help it.  Leave sleeping dogs lie Bob, that's my .02, and I'm out.
EricV

[Doug Moon]

Why this all of sudden out of nowhere?  I could see this when you were competitively flying but you have retired some time ago and now you want to level the field in the name of safety for a compitition you no longer compete in...  You even alerted the AMA to a problem we don’t have...  What is really going on here?  I don’t understand..

[Eric Viglione]

Hi Eric:

Well, I'm not sure where the vitriol came from, and, no, I'm not expecting any "accolades." Actually I was expecting just exactly what you sent, but not from you. Nothing you wrote even came close to answering my question about why it is so bad to have a level playing field and have the models all weighed at takeoff weight and pulled accordingly. It seems that everyone on the IC side of this discussion is bound and determined to belittle my simple request without actually addressing my questions, and some are making it personal. That's fine; I've been in such situations before. I'm just very surprised to find a personal character attack from you on this. That's fine, too. I won't do the same in return; I still regard you very highly. I don't agree with you, sometimes, but I will never make it personal.

Bob

Personal? Vitriol? I am sorry a strong disagreement feels that way to you Bob. I guess this is what happens in discussions where we only see our own side.
I have seen it written that anything other than glowing praise in the world of Stunt can be taken as an attack, and I do apologize if my comments felt like one.
No offense intended, but I did state facts, I DID answer your questions, even if you refuse to see my answers or discount them as non-answers.
I said I was out, and I think I pretty much am on this subject, but I didn't want to leave you with that bad taste, even though this post probably didn't do much to help that.
Peace! 
EricV

[Jason Greer]

Maybe a compromise solution would be to allow electric models to be weighed without the battery.  The pull test would then be based on the weight of the model plus half the weight of the battery.  For example, the pull test for an airframe that weighs 55 ounces and uses a 12 ounce battery would be 61 ounces, not 67 ounces.  This, of course, would require an extra step at the weigh in process.  This would allow the weigh in process of a glow model and the already established line diameter brackets to remain unchanged.

Jason

[Brett Buck]

Why this all of sudden out of nowhere?  I could see this when you were competitively flying but you have retired some time ago and now you want to level the field in the name of safety for a compitition you no longer compete in...  You even alerted the AMA to a problem we don’t have...  What is really going on here?  I don’t understand..

     I don't think it is necessary to assign sinister ulterior motives, and in particular, in this case, the effect on competition is literally and exactly *0* - your airplane isn't going to be built any differently, it's not really going to weigh more, so it will fly exactly the same way it does now.

   This change doesn't matter enough to competition to make an issue of it. I do object to characterizing the current situation as a safety issue - since we have more than half a century of data indicating otherwise and absolutely nothing has changed about the topic. And we just done doing a fairly good and valid analysis to establish the break points. Going straight to the AMA and declaring a safety problem when there is none, and with no consultation, it irritating, but hardly a unique situation.

    But ultimately it is irrelevant and doesn't change anything you would do otherwise.

     It alters the post-weigh-in "weight bragging contest", but anyone who has nothing better to do but argue about that really needs to find a new hobby. I recall several notables (whose names I decline to mention) at some TT bragging about being lightest by 1/2 an ounce and another who swore up and down his 67 ounce airplane actually weighed 56, but the scales were wrong. The heaviest airplane at the contest, at 72 oz, won the contest by a large margin.

   If anything, I would have expected this change to be deferred until now *because* Bobby is retired from competitive flying - because he didn't want to be seen to be manipulating the rules to his personal advantage. I did the same with the "2.4 GHz proposal"- I probably would have outlawed any form of RC or IR control in the mid-90s, but I didn't want to be seen taking advantage of rule changes to "get Windy".

     Brett

[Derek Barry]

     

   This change doesn't matter enough to competition to make an issue of it. I do object to characterizing the current situation as a safety issue - since we have more than half a century of data indicating otherwise and absolutely nothing has changed about the topic. And we just done doing a fairly good and valid analysis to establish the break points. Going straight to the AMA and declaring a safety problem when there is none, and with no consultation, it irritating, but hardly a unique situation.

     Brett

This, and Brett's previous statements, pretty much sum up how I feel about it. I'm not sure why Brett is so eager to attach .015 lines to my plane though. You would think I beat him out of a spot on a US team or something.

While Eric and Doug's statements were blunt, I didn't find them particularly offensive. Maybe I'm a poor judge.... A lot gets lost in text, and you of all people should know that Bob. The question; Why this, and why now is a valid one. I'm also in agreement with Brett on the fact that it makes zero difference, other than a few people's feelings. The electric pilots "fuel" is heavier than my engine, and thier motors are significantly lighter, so some comprise had to be reached, in the name of fairness. That compromise was, electric guys have to carry the battery for weigh in.

If it's really that big of a deal, (and I don't think it is)) I'll compromise again and meet you half way. Add 3.5 oz to my weight, and call it even.

Derek

[Doug Moon]

Are you saying that just because I'm not actively competing that I should have no say in the event in which I spent 50 years? Please tell me that's not your position, Doug.

Of course that is not my position.  I didn't say that either.  Maybe I have been out of the loop on this but this all seems to come out of nowhere and to say it needs an emergency change makes it sound as if this is a dire situation. 

I still revere this event highly, and I am helping a number of fliers to design, build, fly and compete. I'm looking out for their interests, as well as the interests of many other fliers that I don't actively work with. I speak with many fliers, and this subject comes up very often. Many of them are too worried about being bullied by the "opposition," and keep their silence. I'm not so bashful, and I'm certainly not going to be bullied.
 

I have seen plenty of stunt bullying over the years.  Its not good.  Anyone with an active AMA can make a rule change request.  Scrutiny of such a change request should not be taken as bullying.

I do see a problem, and I do think that open, civil discussion is needed on this matter. Many who've posted on this thread understand that and have offered up some great suggestions. Please do not try to get all the IC guys to just gang up on me and defame me over a simple question. Better yet, do that; I want to know people's true character, and I want everyone here to see how one group here can go "main stream media" to try and silence someone.

That is nonsense and for you to think I would do that shows me just what you think of me...   

As far as AMA is concerned, I also have the right to speak with them about my thoughts on any matter concerning safety, and, yes, fairness. You want my guns, too?

Bob

Wow...just wow.

I simply asked you why all of sudden is this such an urgent need and this is the reply....  maybe I am the one being pushed down...


On the topic of safety.  There is are no current situations that show a change to the current way the IC planes are weighed at this time warrants a needed change. That is not a very good sentence but I think you get my point. There are no planes snapping off the end of lines due to the lines being being to weak at the beginning of the pattern when the tank is full.  It's not happening and hasn't been happening.  The history isnt there to say this is a safety issue.

Is it a fairness in competition issue?  There are two sides to the coin.  IC view and the ECL view.  I would say there is not an unfair advantage, imagine that, due to the fact the rules clearly state ECL planes will be weighed with battery on board. IC planes will be weighed with an empty tank on board.  If you don't want to take that hit on the scale then don't build an electric plane. 

The battery 100% charged is the same weight as the battery 20%.  Since 80% of the battery is gone at the end of the flight and 100% of the fuel is gone at the end of the flight for IC planes.  We could add back 20% of the weight of the stated fuel load to make it fair.   That way both models are considered to be sitting at the end of the flight in the same condition with 20% of the fuel load on board. 

Now.....what if an ECL flier decides to weigh in with a little battery on board to beat the scales and put in the big battery afterward......   

[Brett Buck]

Yeah, Brett, there's no way I want to open us for more "exposure" by outsiders than necessary, and I certainly don't want any "additional" constraints put on the event.

I guess I am a bit guilty of just wanting to "level the playing field." There is still in my mind a safety issue, but there is also most certainly a "fairness" issue. Why can we not level the playing field for all concerned - even if it is a "perceived" advantage/disadvantage? Is there a way we can just weigh all the models flown at an event at their takeoff weight and do the pull testing accordingly?

  Well, by merely broaching the subject, now anyone can argue that there is a "controversy" over the pull test rules. You created one.

    And anyway, as I suspected, this has nothing to do with safety, and everything to do with "fairness" - whatever that means. In this case, it means exactly nothing, because *absolutely nothing will be changed* about how the airplanes are built or how they fly. The effect of this will be to raise the pull test requirement for IC models by around 4 lb. I know for certain, having tested it, that at least parts of my system will take more than 220 lbs (guess where that comes from...) since I put 220 lbs on it and it didn't break. So adding 4 lbs will make *no*, repeat, *no* difference.

    If anything, marginal systems will see more stress during the test and be more prone to fatigue failure. Great safety innovation - that's one of the things you have to consider when you define margins for testing parts. If you require a 10x test instead of a 4x test on the flight parts, you create failure scenarios that wouldn't have occurred otherwise.

   So changing this will not "level" any playing fields, if anything, at most it might cause an occasional additional IC failure either during test or flight, but not enough to bother worrying about - because you had darn well better have more than 4 lbs of margin on a 40 lb test. Otherwise, *the airplanes will be exactly like they were before* in all respects. So what have you changed from a competitive standpoint?

    I could live with the alternative - take the battery out for weighing. It accomplished the "level" goal equally well, by ALSO NOT CHANGING ANYTHING that matters. I guarantee you and no one else is going to be able to take advantage of a 4-5 lb lighter pull test by designing the system to be slightly weaker and in any case, if you save an ounce of control system weight on a 72 ounce airplane and think you can tell the difference, you need a better design.

   I am sure that the latter will appeal to you, because then you won't have to report you built a 62 ounce airplane anymore, you can say it is 55. Why that makes any difference is beyond me but I know that this is a point of directed urination during the week. Using that as a figure of merit for construction skills is a relic of 1975, but then again...

    Note also that now you have probably *torpedoed* that option, because you claimed it was a safety problem, and it's going to be really hard to go back and argue that to solve your safety problem, you are now going to *reduce* the pull test for electric rather than raise it for IC.

    Brett

[Derek Barry]

I will not go to the AMA to effect these changes; I will work through the CLACB.


Bob Hunt

Well, considering who you are, and knowing that you will do an excellent job of writing the rule proposal, I think you have a good chance of accomplishing your goal, and winning the vote with the CLACB. Congratulations in advance.

My take off weight does change from flight to flight, considering weather conditions, and if I can remember how much fuel to use, so..... We are splitting hairs anyways, aren't we? 😉

Hope you are doing well Bob,
Derek

[Randy Cuberly]

I just went to my shop and weighed one of my PA65's with a header pipe, Carbon pipe, a rubber duckie, and a 6 oz typical metal tank (empty).  They weighed 18.4 oz.  (These are actual parts that came out of my Whitely Shoestring).

Can one of the electric whiz guys please tell me what a typical similar (modern) electric power set up with motor battery and assorted electric gizmos weighs.  Please, no guesses, weigh the parts! 
I suspect the difference is heavily in favor of the IC system but would like to know how much would have to be added to the IC sys (fuel) to make them approximately equal!.

Thanks,
Randy Cuberly
 

[Fred Underwood]

Perhaps I have misunderstood the impact of a rule change.  In light of the thread on Ukraine lines, the weight cutoff of 64 ounces becomes more interesting.  A couple of ounces weight plus for IC, or minus for electric could change who is allowed the 0.016 Ukraine lines.

[Jason Greer]

Randy,

I’m by no means an electric whiz, but I happen to have some pieces in my shop that would power a typical 60 size electric model. The component weights, in ounces, are as follows:

Motor 6.3
Battery 12.8
Esc 1.9
Timer 0.3
Total: 21.3

You didn’t mention if your weight included the spinner and propellor, so I didn’t include them.

Jason

[frank williams]

Fred you hit it pretty close ...

The issue is the line size break .... some are treating the issue as if some planes have to fly with an increased weight ... a big blob of clay that some have to fly with and others don't ..... the issue is the 64 oz break from 0.015 to 0.018's.  Although many say that they wouldn't fly with the smaller lines, they really would like to have the option and those 4 to 6 extra ounces make a difference.  A bit extra on the pulltest isn't a deal "breaker".  Not being able to take advantage of thinner lines is.

Which brings me to my argument ...

....  since we re-did the rules for electric with the 10g pulltest and kept the line size requirement, we are very much "over specifying" the line safety requirements.   10 g's is a bunch of pull, too much in my opinion,  but then on top of that we still specify  line diameter, a hangover from ic only.  10g's is enough with no specification on diameter, just like FAI.  Keep the 0.015 and 0.018 and 0.021 diameter words as "recommendations only" and not requirements. 

... if the rule says 10g's only, then there is no diameter advantage, use what you like.  Yes there will be a slight pulltest difference for ic and electric, but the consequences are only in the pull. 

The issue here isn't safety, its that everyone wants to hit the sweetspot in weight that will allow smaller lines. 

[Brett Buck]

The issue here isn't safety, its that everyone wants to hit the sweetspot in weight that will allow smaller lines.

  I agree that the line size breaks don't make any sense, and I would go with "if it passes the pull test, its OK".

  But I slightly dispute the concept that we are trying to hit the magic number to use .015s. After the 2003 NATs, where I could feel my 63 ounce airplane stretching the lines and deflecting the bellcrank at the bottoms of the round loops - on .018s, and Allen Goff's airplane broke away completely, there is no way I am flying a 63 ounce tuned pipe airplane on .015 stranded. And, every time I try it, I find myself having to put control input in about half-a-second early just so the controls move by the time I need them. My airplane flies much better and is much easier to control and more precise when I run on .018s.

    Brett

[Brett Buck]

This, and Brett's previous statements, pretty much sum up how I feel about it. I'm not sure why Brett is so eager to attach .015 lines to my plane though. You would think I beat him out of a spot on a US team or something.

  The +0.04 would turn into about a -15.

   Brett

[frank williams]

Hi Brett
In 2003 I switched to 0.014 solids in the wind.  The fact that 0.015 stretch in the wind is a fact.  Yours didn't break though.  Alans I think was a shortcut across the circle.  Without a diameter specification, 10g's only is plenty safe.

[Chris Cox]

As I tried to say earlier, I do not think safety is an issue.  My only point, and Frank confirmed that point, was that I am not able to fly the .015” lines with my 65 ounce electric plane, whereas an IC model that weighs in at 63 ounces can then add 6 or 7 ounces of fuel and still use the .015”lines. (The weights I just threw out there were examples only). I would like to have the option to try the lighter lines, but under the current rules I can not, and clearly it is not because of a safety concern.

Again, as Frank alludes to, is line diameter even an issue if they meet the 10g pull test?  Has there been a higher line breakage percentage at FAI based contests?  Don’t think so.

And after all that, I may still very well opt to use the .018” lines to avoid line stretch by the 15 thou lines..., but it would be nice to have the option.

[Doug Moon]

I agree with the 10g only pull.  I have always thought that is a great way to do it. It makes sure the ship is airworthy for the next flight and there is no need to worry about diameter. 

[Derek Barry]

Hi Derek:

Thanks for the kind words. I suspect this is a lot of noise for nothing. Several of my friends who happen to fly electric have groused about the real or perceived inequities of the pull test situation glow versus electric. I was just wanting to voice their opinions as well as my own. Obviously it got out of hand. From here on in I'll only make posts about building and innovation in construction techniques. That certainly can't get me into trouble... 

Hope you and your family are doing great. How's the house renovation coming along? Hope also that you have a great flying year and finally take it all home. You are quickly becoming like my favorite NASCAR driver, Chase Elliott. Always second. I'll root for you this year no matter what type of power you have in the nose...

Bob

Hey Bob,

I hope that you will always voice your opinions, as well as those who you consider friends. This is still America, right? In this time of great division, those of us who value freedom need to be able to have vigorous debate. Many of us are on edge, mainly, because we are always defending what seems to be a common sense point of view. Just know, that you are among friends, and don't take offense to strong opposition. It's what makes this country great, and creates friendships that can't be broken. You and I have had many disagreements, but we still connect on the important stuff...

As for the house, construction is ongoing.... We have looked at buying another house, and coming back to this one many times. There really is no rush, and our family is very close, literally and figuratively. Thanks for asking, and thank you for your support. I'm not sure how this year will go, as far as competition is concerned. I haven't had much time for airplanes, with work, and other life stuff, but we will see. I enjoy the fellowship as much as anything else, winning is just a bonus.

Derek

[Brett Buck]

Hi Brett
In 2003 I switched to 0.014 solids in the wind.  The fact that 0.015 stretch in the wind is a fact.  Yours didn't break though.

  Mine were .018s!  If it was that bad with .018, what is going to happen with .015 with 70% of the cross-section? I don't care to find out.

     Brett

[Dan Berry]

I'm gonna poke my head in here.

As I'm seeing things the real result of the proposed change would simply be requiring some to use 018 lines which almost everyone flying one of those behemoths is already gonna do?

Seems like a lot of sturm and drang over minutia.

I must say that I saw no vitriol or denigration in any posts. I can tell you guys that the Free Flight Community is in another battle where a guy who does not and cannot fly an event is trying to initiate rules that are beyond stupid. Be thankful that ukie stuff isn't dealing with that sort of B.S.

[Brett Buck]

I'm gonna poke my head in here.

As I'm seeing things the real result of the proposed change would simply be requiring some to use 018 lines which almost everyone flying one of those behemoths is already gonna do?

Seems like a lot of sturm and drang over minutia.

     The effect of the change itself is trivial to non-existent. It would have been just as good to remove the battery from electrics, which lets everybody go on the same basis - but also has trivial to non-existent effect on competition. The big issue I had with it (specifically, treating this like an emergency safety issue, which is assuredly is not), Bobby is going to now drop. So I have no real objection.

     Steve Yampolsky is going to propose removing the line size restrictions (again) and if that passes it makes this change entirely moot.

   There is a very unfortunate tendency to immediately suspect everyone of sinister ulterior motives with these things, but for the most case, the motivation is entirely irrelevant, it's either a good idea, a bad idea, or irrelevant.   This one is almost irrelevant, with very minor effect in a few corner cases.

    Brett

  p.s. I got an off-line PM about "new Ukrainian lines". These sorts of lines have been available in various forms for at least 50 years, the latest versions may be better but I have similar lines that originated with the Yatsenkos. As above, you might be able to get away with these and get a small improvement in a few corner cases, but as long as the line size requirements remain, the cases where you get substantial improvement are, I think, pretty narrow.

[Paul Walker]

Bob, and all...

I have been following this thread during my breaks from the WSR grass circle sprinkler improvement. It got quite boring digging trenches for new sprinkler lines. During one of those mind numbing sessions I got an idea.

Brett is right about all the data we have that the line sizes are right for IC. Based on some of the discussion I realized that the information we need is already available!

For instance, consider a 64 (-) ounce IC plane. Figure it has a 6 ounce tank. So the average fuel load is 3 ounces. So data suggests that a 64+3=67 ounce plane on 0.015 braided lines is safe. To make electric and IC "equivalent" in a safety aspect, a 67 ounce electric plane would be just as safe.

So, to get the equivalence you are looking for, why not have separate line size requirements for electric and IC? Instead of 64, electrics would be 67. The other "break" points would also be slightly higher for electric.  The pull test would be unaffected by this as it would still be 10x of the weight.

Does this not get the equivalence you are looking for Bob?

[M Spencer]

Yep , and a seperate devision for Elec. in intl. comp.  and a CONSTRUCTORS Championship ( Make ) seeing its no longer ' Home Made .

maybe .  We can get too carried away about ' Equality ' . If All People were equal , Adolf Hitler , Attila the Hun , Col. Idi Amin ( curtosey the British Army )
and a few otheres , would bbe equal to say Muhatma Coat Gandi , Mother Tarresa , John Lennon , and Hillary Clinton. What, wrong group there )
 

Parity and Equality , maybe . but other things to consume thought , thanks .
Have a book of quotes , one of which is " Anyone who thinks everone is equal is clearly insane "

Biblicly its ' Equal in the Eyes of God ' which aint neccesarily ' The Same ' .
Also as EVERYTHING was CREATED at the Beginning of Time ! , some ' beings ' have been / become more aligned ,
than say the TV producers and Hollywood . 

Anyway . the Pre Advertising , 60s Grand Prix , when it was more a Gentlemans Sport . Than a COMERCIAL RACKET ,
the rules were less overwhelming and restricting .

The Pre War ' 750 Kilo ' formular had 200 mph plus BACK THEN .

Nailing the big jump in dia. at 65 Oz or whatever it is , if it hasnt been done , should be .
Again I think it was sore loosers who put the 2 mitre span restriction in FAI as they couldnt do a P W B-17 themselves .
A WEIGHT RESTRICTION O.A. of say 2 Kilo , might have been sane. a Span Limit is a Restriction .

Incidently , if you full your plane with helium or hydrogen , itll still have a MASS / Inirtia of Its Weight , even though ' negative ballasted .

Really I think ELECTRIC is a SEPERATE Formular Matematically , regarding many things , its pulling the I.C.E. stuff around with it ,
in the regulations , as the 4 strokes did with capacity . Not that it matters a stuff .

As long as it dosnt bind things up rather than stimulate  actual ( aerodynamic ) progress .

[M Spencer]

The Can Am Racing was the most Rule Free & Spectacular . ( The Kiwi's Winning .  )



We dont need to get to carried away and pedantic , until the prize moneys equal to Wimbleton . Wrong Flushing Meadow  apparently .

( Thats a road car . The Real one sat at McClaren Motors . The Bloke said he couldnt find the keys , when I asked if I could have a drive )

[Brett Buck]

As an interesting aside, when we were pulling based on engine sizes, a lot of us got 45 lb pull tests on 45 ounce ST46 airplanes - 16Gs instead of 10.

    Brett

[Trostle]

(Clip)

Which brings me to my argument ...

 we are very much "over specifying" the line safety requirements.   10 g's is a bunch of pull, too much in my opinion,  ------

(Clip)

Hi Frank,

I am not really taking exception to any of your statements on this thread.  One point though regarding the "adequacy" or efficacy of the 10G pull test.  Yes, it is a lot, but well within the bounds of properly built control systems with the specified line diameters.  However, I offer two observations.  Several years ago, I attended the Nats and was helping one of the competitors on the top 20 day.  He has been in the top 5 before and is an excellent builder.  One of his leadouts failed on the pull test not even when it was at its required 10G pull test.  The leadout failed where it had rubbed against the internal landing gear wire after countless flights.  He only lost the leadout wire and maybe some slight damage to the controls when the one line failed.  If this had happened during the next flight, the entire model would have been lost.

The 10G pull test requirement is to test the control system with a certain safety factor even if one line fails in flight.  I lost a cable in the control handle just before an official flight at VSC several years ago.  The up cable failed on an outside square.  The model then continued to do outside loops until the inevitable happened and pancaked upside down on the pavement.  Sort of gave a helpless feeling.  The one line/cable still kept the model in the circle.  Maybe a pull test prior to that practice flight would have shown that cable was ready to let go before I lost the entire model.

Keith

[Tom Niebuhr]

There is doubt that we have accurate history on IC airplanes.  Possibly the separate pull test categories could work. But, as said by many the safety factor on lines is already there.

Personally I have no use for solid lines. I've been doing this for 50 years and the only line break I have ever had was with solids!  Legal diameter, and no free flighting across the circle with a snap at the end. They were not old lines either. 

Then adding the solid lines sticking in humid weather and that they are  almost impossible to keep clean, I just don't trust solid lines. 

That aside, 10G pull is probably the best way to go.

[Brett Buck]

The 10G pull test requirement is to test the control system with a certain safety factor even if one line fails in flight.

  It is certain, and well-known - the pull test is a factor of about 2 over the load of one line in steady-state flight, which not coincidentally is also about half the industry-standard test strength of the line. The pull is about 2.5Gs, and the test is 10Gs, so about a factor of 4 over the flight loads.

   I think that is about right, it weeds out the worst cases where it is about to fail in-flight, and still provides restraint of the model with some margin if one line does fail in flight - without imposing a significant performance burden. It's also consistent with the very extensive historical range of experience, with some refinement that prevents the sort of thing I mentioned above (16G pull tests due to a mere quirk in the rules).

    Brett

     

[Brett Buck]

Which brings me to my argument ...

....  since we re-did the rules for electric with the 10g pulltest and kept the line size requirement, we are very much "over specifying" the line safety requirements.   10 g's is a bunch of pull, too much in my opinion,  but then on top of that we still specify  line diameter, a hangover from ic only.  10g's is enough with no specification on diameter, just like FAI.  Keep the 0.015 and 0.018 and 0.021 diameter words as "recommendations only" and not requirements. 

   I would be curious what you would consider a pull that is not excessive. For years, we were pulling quite a bit more than 10Gs in many cases, so if anything, the 10G VS engine size change probably made it go down, not up, for most current airplanes. I would be pulling 45 lbs under the old rules, now I pull 41. I kind of like a factor of 2 as a goal and a reasonable compromise.

   I think we all agree on the need for line size requirements, i.e, there is no engineering justification for requiring particular sizes as long as you don't also specify the strength (which we DO NOT want to do, since it's effectively impossiblel to check in the field). But I think that the idea that you are shooting for 63 ounces or whatever so you can use .015s  is not much of an argument - although I won't be rushing to stop anyone from shooting themselves in the foot that way.

     Brett

[Howard Rush]

When I read the initial post of this thread, I had to check its date twice: I was pretty sure it had to be April 1.

Mind you, I am accustomed to a sport that has half a dozen or so flyaways per contest.  Yes, I was there at the horrid Allen Goff Nats flyaway.  I was on Circle 3 flying a 69 oz. airplane on .015" cables.

If you want a rule change, I suggest one that provides adequate safety with reduced bother.  Dropping line size minima should accomplish that.

[Frank Imbriaco]

Yep , and a seperate devision for Elec. in intl. comp.  and a CONSTRUCTORS Championship ( Make ) seeing its no longer ' Home Made .

maybe .  We can get too carried away about ' Equality ' . If All People were equal , Adolf Hitler , Attila the Hun , Col. Idi Amin ( curtosey the British Army )
and a few otheres , would bbe equal to say Muhatma Coat Gandi , Mother Tarresa , John Lennon , and Hillary Clinton. What, wrong group there )
 

Parity and Equality , maybe . but other things to consume thought , thanks .
Have a book of quotes , one of which is " Anyone who thinks everone is equal is clearly insane "

Biblicly its ' Equal in the Eyes of God ' which aint neccesarily ' The Same ' .
Also as EVERYTHING was CREATED at the Beginning of Time ! , some ' beings ' have been / become more aligned ,
than say the TV producers and Hollywood . 

Anyway . the Pre Advertising , 60s Grand Prix , when it was more a Gentlemans Sport . Than a COMERCIAL RACKET ,
the rules were less overwhelming and restricting .

The Pre War ' 750 Kilo ' formular had 200 mph plus BACK THEN .

Nailing the big jump in dia. at 65 Oz or whatever it is , if it hasnt been done , should be .
Again I think it was sore loosers who put the 2 mitre span restriction in FAI as they couldnt do a P W B-17 themselves .
A WEIGHT RESTRICTION O.A. of say 2 Kilo , might have been sane. a Span Limit is a Restriction .

Incidently , if you full your plane with helium or hydrogen , itll still have a MASS / Inirtia of Its Weight , even though ' negative ballasted .

Really I think ELECTRIC is a SEPERATE Formular Matematically , regarding many things , its pulling the I.C.E. stuff around with it ,
in the regulations , as the 4 strokes did with capacity . Not that it matters a stuff .

As long as it dosnt bind things up rather than stimulate  actual ( aerodynamic ) progress .

Matt : Please allow me to suggest that you start in earnest, like today, to go play elsewhere.

[Perry Rose]

Instead of "what size tank" How much fuel do you take off with? would be better.One of my planes has a 6 ounce tank and I use 4 ounces per flight.

[Lauri Malila]

. Why should we not also accept their word about tank size? If someone is flying a model powered by a .75 and they claim they have a four ounce tank on board, well...

Just a suggestion.

Bob Hunt

My .77 needs 2,8oz per flight Bob.. L

[Al Rabe]

Goodness,

There is a lot of heat over something which can be handled simply which would affect all gas flyers equally and with a fair approximate weight not too far from actual weight.  Simply add one ounce for each .10 of displacement to the scale weight of the airplane. My F-51,s would add 6 ounces to its scale weight.  My Bearcats and Critical Mass would add 7 ounces to their scale weight.  Fox .35 airplanes would add 3 ounces and so forth.

If Brett and Bob think think that we have a problem with catching cheaters by adding unnecessary complication to the rules, how would they respond to flyers removing tipweight prior to being weighed in? We can't guard against every possibility for cheating and shouldn't dignify the efforts of cheaters by making rules solely to catch them..   

Al

[Brett Buck]

This may be a moot point, but at only one contest in the last 20 years has this actually been done, mainly checking with a micrometer, the size of my flying lines during  the pull test and this was at St Louis ten years ago. Never before nor since  has anyone ever checked my lines for size. Just pulled based on engine size and now pulled on the models weighed in weight, on some very inaccurate scales in most cases, out side in the wind with the weight all over the place. FWIW

   The point about tolerances is right on the mark, the rusty, 60-year-old fish scales commonly used for pull tests and sometimes for weighing the airplane is hardly precise enough to consider the fuel mass variation. Take the stated bias and scale factor stability of a common post office scale when used outdoors when it is 105 degrees, or when it is 45 degrees, and then multiply that by 10. Then throw +-5 lbs at best for a 60-lb fish scale.

 
   However, the line sizes are spot-checked at times, almost every year at the NATs, and not uncommonly at local contests. Just like everything else, if there is a clear rule, people will follow it whether they might be able to get away with cheating most of the time. If nothing else, if you get caught cheating just once, your reputation is bad forever, because everyone will find out - and the entire point of the event is to gain the respect of your fellow competitors. But for the most part, people will not cheat because they are basically honest, particularly so in the stunt event.

     Brett