A weighty situation

[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?

[Air Ministry .]

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 .

[Air Ministry .]

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.

[Bob Hunt]

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?

Hi Paul:

Never pictured you as a ditch digger... Get that all done before the heat comes...

Yeah, what you proposed would certainly quell the argument (discussion?). All the electric guys are looking for, as far as I've heard, is some equity. Your suggestion would accomplish that.

My father told me the story about how my "real" name of Robin came about. It seems I was in the maternity ward as a baby and when all the other babies were sleeping I would squawk like a Robin and get them all crying. Then I would stop squaking and just listen to them cry with a wry smile on my face. It seems I haven't changed much...

It's all good if we get real and meaningful discussion going, and that appears to be what is happening here. I truly love this event and want only the best for it in perpetuity. I we can "level the playing field," then it will be healthier in the long run. At least that's my take on it.

Paul: Can I work with you to write a proposal that will do what you have suggested?   

Later - Bob (Robin) Hunt

[Bob Hunt]

Okay, here's one more thought on this subject:

It seems that many are opposed to the idea of weighing the model at takeoff weight because of real or perceived problems at the weigh-in point. Dripping fuel in the 180 building was brought up by one respondent. That's a valid concern for sure. Here's a possible solution. Just ask the entrant before the weigh-in what size tank is in the model and than multiply that by the actual weigh of a fluid ounce of fuel, add that to the model's dry weight, and then do the weigh-in and administer the pull test accordingly. We already accept the entrants word on the BOM issue. If they say they built it, then they are legal... 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

[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

[Bob Hunt]

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

Whoo boy does this hit home with me. I've gone to many contests where they neither check line diameters, weight the models, nor did pull tests! That is a separate matter from this thread, but one that deserves it's own thread. I was a CD at a meet and one contestant actually asked me if we were going to pull test. When I said, "yes," he looked at me sort of weird. But, hey I'm used to that...

Good post, TY.

Bob

 

[Bob Hunt]

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

Point taken, Lauri! 

Bob

[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

[Gerald Arana]

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

This I gotta see! 

Jerry

[Doug Moon]

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.

Al

That’s a good idea. Simple and straight forward.

[Brett Buck]

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.

    Yes, that would be a potential "solution". That of course presumes that there is a problem to solve in the first place (which, given the other tolerances, there isn't). And as soon as you did that, the people who are worried about the problem will want to either measure everyone's engine (he said it was a 46 but it's really a 75), and/or argue that 7.5 ounces is not enough for a 75, since David runs about 8.5 ounces in his, not 7.5.

   If this was a real safety issue, then it might be worth considering, but when you have the same airplane being weighed from 62 ounces to 67 ounces (which is the range I have gotten over the last few year (and its really 66.5)) and using a rusty fish scale with a calibrated eyeball deciding when to release the pull, these variations are all in the noise. To significantly improve it you would need some sort of calibration program for the measuring equipment, which we don't need to do nor are we going to do.

   This is more about the electric fliers feeling aggrieved over having to weigh with the battery in. A simpler solution would be to allow them to weigh the airplanes without the battery, and counting on the margin to cover the difference. I am not sure what Frank has in mind for a "reasonable" pull test, but his point is that 10G is too much. Leave out the battery, and it's 7.5gs or something for electric, and about 1.6x over the flight loads instead of the (by design) 2x. I can live with that, it's not like IC airplanes are flying off the ends of the lines with an *actual* 1.7x (once you add 8 ounces of fuel).

     Brett

[Tom Luciano]

Im looking at this in a little different perspective, as I see a tie with the Ukraine line thread. My electric plane comes in at 63.5 oz ready to leave the ground. Im waiting for the one time im weighed in and im over.  So, Im Flying the 4 strand 016 lines. The day i come in overweight my lines are now illegal.  Yet, the guy with the IC engine that weighs 62 oz.dry, fuels his plane and takes off at 67 oz legally with 016 lines. Thats my issue. I couldnt care less if  me or  IC Joe pulls an extra 5 pounds .
My 2 cents
Thanks

Tom

[Charles Carter]

It is 2018 and we are still using stainless steel wire?  How long has stainless steel wire be around?  Didn't we at one time use wooden bellcranks connected to stainless steel wire?  If you have noticed we don't use wooden bellcranks anymore but we are still using stainless steel wire. We have modern and sophisticated model airplanes connected to old technology.  Do you realize all the technological gains made in fishing line industry?  If we used modern technology to connect to our handles and airplanes we all could benefit from using thinner and better lines.   Wouldn't the “line break” point be elevated to the point where both IC and electric models could both be flown on the same thin lines because there actual take off weight would be well below the “line break” of the same thin lines?

[Joseph Daly]

Although I am new to stunt, I do not understand why we would not have the same playing field? To me it should be equal. I did like Paul’s idea about adding weight to equal the playing field. This is much like NASCAR they make all the cars weigh the same and in the top series’s they also figure the weight of the driver so that they level the playing field. The lower ranks they simply weigh the car with the driver in it and make all cars equal for the most part. This is just my opinion, I agree with what Bob is trying to do and I think it is the right thing to do.
Thanks
Joe

[Dave_Trible]

I would be more in favor of weighing/pulling the electric battery free, or a little less knowing we have a substantial safety factor built in.  I have nothing under 70 ounces and always use .018 and always feel like I need to tie my butt to a tree to pull the planes.  It will take it for sure but I can't see having to pull any more when it has nothing to do with me.  I'd rather make whatever adjustments the other direction.

Dave

[frank williams]

   I would be curious what you would consider a pull that is not excessive.

 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

I don ‘t necessarily feel that 10 g’s is too much, but ten 10 g’s with also an imposed  “stair step” line diameter minimum  is over specified I feel.  The “stairstep” diameter specification is a remnant of the previous ic rule.   Nominal flying g’s are 3, a runaway ic is probably about 5 g’s.   Simply a 10 g pull is satisfactory.

At present I’m shooting for 63 oz’s …. Yes, not so much to use 0.015 stranded, although some planes will tolerate them, but to take advantage of the 0.012 solids.   10g pull before you fly and you’re ready to go.  Maybe a =/- delta for ic/elec if needed.

[Brett Buck]

At present I’m shooting for 63 oz’s …. Yes, not so much to use 0.015 stranded, although some planes will tolerate them, but to take advantage of the 0.012 solids. 

   .012 SOLIDS!  Wow, that is not something I would have contemplated as an issue.

   Brett

[Brett Buck]

It is 2018 and we are still using stainless steel wire?  How long has stainless steel wire be around?  Didn't we at one time use wooden bellcranks connected to stainless steel wire?  If you have noticed we don't use wooden bellcranks anymore but we are still using stainless steel wire. We have modern and sophisticated model airplanes connected to old technology.  Do you realize all the technological gains made in fishing line industry?  If we used modern technology to connect to our handles and airplanes we all could benefit from using thinner and better lines.   Wouldn't the “line break” point be elevated to the point where both IC and electric models could both be flown on the same thin lines because there actual take off weight would be well below the “line break” of the same thin lines?

    GSUMP lines are something being experimented with in other venues, so far, no one has proposed them for stunt (along with the necessary engineering evaluation) and termination requirements. I don't know enough about them to do it myself.

     Stainless steel stranded lines have the advantage of 70-ish years of experience with very-well-understood characteristics. That is not irrelevant to the discussion.

   Brett

[Rick_Huff]

Seems to me that this issue is mainly centered on the line diameter requirements.  I agree with Brett that a few pounds, more or less, in the pull test doesn’t matter very much.  However, the line diameter requirement does have an effect on the way the plane flies.  Whether you like the reduced drag of smaller diameter lines or the stiffer more responsive feel from larger diameter lines, shouldn’t it be left up to the pilot to decide what they like?

Rick

[Randy Cuberly]

Seems to me that this issue is mainly centered on the line diameter requirements.  I agree with Brett that a few pounds, more or less, in the pull test doesn’t matter very much.  However, the line diameter requirement does have an effect on the way the plane flies.  Whether you like the reduced drag of smaller diameter lines or the stiffer more responsive feel from larger diameter lines, shouldn’t it be left up to the pilot to decide what they like?

Rick

Yes, especially if the smaller diameter lines are stronger (or just as strong), and stretch less as in the case of some of the currently available stuff!

Unfortunately, most safety provisions while suggested by engineers are most often decided by lay politicians!

Randy Cuberly

[Trostle]

Point taken, Lauri! 

Bob

Bob,

Have you ever seen one of Lauri's engines.  They are a masterpiece of machining and they run extremely well.

Keith

[Dan McEntee]

One thing that is lost in this discussion, is that , yes, an IC model takes on 4 to 8 ounces of fuel for take off, typically. But as soon as the engine is started, that weight starts coming off and continues to come off until the end of the flight. Electric models weigh the same throughout the flight. Yes, that is all very obvious but I'm gonna guess that whoever was involved in the new pull test rules took that into consideration. When does everyone think that the most stress is on the lines, the beginning, middle or end of the pattern?  Some may say that the most stress is in the latter half of the pattern after the triangles, and by that point, about half the fuel/weight or more is gone. When it comes to the idea of fairness or who has an advantage, I would say it is all in the electric court. They can build a model that weighs the same and balances the same throughout the flight. I think that would kind of "balance" against having to pull a few pounds more. Some where in the concept of trying to get an electric model weight down to where you can use smaller diameter lines is the right size/wing area/wing loading to achieve that. The answer to that question may lay entirely in a new model design to best use the consistent dead weight that is the electric power plant. So far, most people are just converting existing design with slight modification to mount the equipment. With as much success that the electric stunt model has had, I feel that there is no disadvantage to the extra weight. You just have to learn to work with what you have and design an air frame to give you want you want, not just "build a lighter model." I hope that makes sense.
    Type at you later,
   Dan "Gimme My Nitro" McEntee

[Ken Culbertson]

Seems to me that this issue is mainly centered on the line diameter requirements.  I agree with Brett that a few pounds, more or less, in the pull test doesn’t matter very much.  However, the line diameter requirement does have an effect on the way the plane flies.  Whether you like the reduced drag of smaller diameter lines or the stiffer more responsive feel from larger diameter lines, shouldn’t it be left up to the pilot to decide what they like?

Rick

I agree 100%  The pull test should be the qualifier and you should be able to fly on sewing thread if it will pass the pull test.  I for one would like to see a bit more lbs added to the test.  When these big heavy planes lose tension overhead and hit the lines on the other side of the circle they pull a whole lot more than any pull test.  Why do you think we have to wear that sill noose around our wrists.  Most everything I fly has a floating bellcrank and properly mounted it can take double the required test.  I say up the pull test and drop the line size requirement entirely but that's just me and I could be wrong!

[Brett Buck]

This I gotta see! 

    That is perfectly plausible, he is using very advanced techniques to maximize the specific output, and can do it because he is building the engine from scratch. I also expect that he is running a very efficient propellor.  We take existing engines and figure out how to make them run, and sometimes that means using very inefficient systems and just building a bigger fuel tank.

    Brett

[Steve Helmick]

While I really don't care even a little bit about making it either "fair" or "equal" for electron burners, I am somewhat shocked that you all seem to agree and accept that one fluid ounce of high alcohol content fuel would equal one ounce of weight. It seems to me like the proposal is for one fubar to replace another fubar in the rules. Since I have no idea how much your battery measures in fluid ounces...leave it alone.  Steve













 

[Dave_Trible]

While I really don't care even a little bit about making it either "fair" or "equal" for electron burners, I am somewhat shocked that you all seem to agree and accept that one fluid ounce of high alcohol content fuel would equal one ounce of weight. It seems to me like the proposal is for one fubar to replace another fubar in the rules. Since I have no idea how much your battery measures in fluid ounces...leave it alone.  Steve

Steve our methanol is something like .82 oz. weight per ounce fluid-less oil.  For discussion purposes it's close enough 1-1. What is strange about that is I can readily feel 1/2 oz. of lead nose weight on the planes.  I don't seem to notice losing 7 oz. in the nose while I fly.

Dave

[Brett Buck]

While I really don't care even a little bit about making it either "fair" or "equal" for electron burners, I am somewhat shocked that you all seem to agree and accept that one fluid ounce of high alcohol content fuel would equal one ounce of weight. It seems to me like the proposal is for one fubar to replace another fubar in the rules. Since I have no idea how much your battery measures in fluid ounces...leave it alone.  Steve

     I was figuring about 6 ounces for my 7.1 ounce tank, which seems pretty close to me.

     Of course, if you accept the concept that the tolerance stackup leads to about a 5 lb tolerance in the actual pull test, the difference is completely lost and moot.

     Brett

[Brett Buck]

Steve our methanol is something like .82 oz. weight per ounce fluid-less oil.  For discussion purposes it's close enough 1-1. What is strange about that is I can readily feel 1/2 oz. of lead nose weight on the planes.  I don't seem to notice losing 7 oz. in the nose while I fly.

     Try doing the hourglass first.

      One of the things I notice when flying Classic airplanes, even with 4 ounces of fuel, they go from too sluggish to too sensitive from beginning to end because the tail volume is so small.

      Brett

[Dennis Adamisin]

I think we did the right thing a few years back when we retired the pull test based on engine displacement and introduced the pull test based on model weight.  However, we ALSO  defined minimum line sizes at different weight points. 

The point that Bob made in his original post was essentially that we did not quite complete the deal.  The criteria we use for weighing electric models makes perfect sense.  We would have an awful hard time explaining to a third party why we would not treat an IC airplane by the same criteria. 

However, I want nothing to do with bringing fueled models into the "180" building for weighing!

Since our minimum line sizes and pull test are based on weight, there is an opportunity to simply use DIFFERENT weight tables to drive the minimum line size requirement.  I suggest using the current weight schedule for electric models with batteries installed and use a different (lighter) weight schedule for IC powered models with empty fuel tanks.  To show how that would work I prepared the example below, based on modifying the table we have in the rule book.

We could argue (discuss) whether the weight differentials correct, but I think something in this format is a workable solution that would be easy to administrate.  NOTE: had a devil of a time getting column alignments - please pardon the mess!


  Electric Powered            IC Powered                  Required Minimum Diameter of Each Line                      Pull Test
w/Battery Installed   w/Fuel Tank Empty                Single Strand              Multi Strand           
      (ounces)                (ounces)                        1 Line   2 Lines                 2 Lines                  Electric                     IC Powered
---------------------   ----------------------             -------     --------              --------                  ---------        ------------------------------------------
       0 - 14.0                   0 – 12.0                      0.014"    0.008"                 0.008"                   10 g             10g based on model weight plus 2 oz
   14.1 - 40.0             12.1 – 36.0                       0.014"    0.010"                 0.012"                   based on       10g based on model weight plus 4 oz
   40.1 - 64.0             36.1 - 58.0                       0.014"    0.012"                 0.015"                   model           10g based on model weight plus 6 oz
   64.1 - 80.0             58.1 - 72.0                       0.016"    0.014"                 0.018"                   weight          10g based on model weight pus 8 oz
   80.1 - 123              72.1 - 113                        0.021"    0.018"                 0.021"                                       10g based on model weight plus 10 oz

I admit the weight differential would over-compensate for the fuel load on Lauri's magnificent engine! 

[Randy Cuberly]

It would seem that the airframe on and electric airplane, especially the fuselage could be build significantly lighter than on an IC airplane.  There is far less vibration stress on the airframe.  Wood in the fuselage could be thinner and even lighter.  I would think less hardwood and plywood would be required.

I know for a fact that a couple of the nicely finished electrics here in Tucson weigh less than some of the similar sized IC airplanes.  That would mean that the airframes would have to be very light.

John Callentine's 650 sq in electric for instance weighs 61 oz with battery installed.  most of the similar sized IC planes here weigh at least that much with no fuel on board!

Or am I all wet about this!  I have very little real electric experience but it just seems logical that they could be built lighter!

Randy Cuberly

[RandySmith]

One thing that is lost in this discussion, is that , yes, an IC model takes on 4 to 8 ounces of fuel for take off, typically. But as soon as the engine is started, that weight starts coming off and continues to come off until the end of the flight. Electric models weigh the same throughout the flight. Yes, that is all very obvious but I'm gonna guess that whoever was involved in the new pull test rules took that into consideration. When does everyone think that the most stress is on the lines, the beginning, middle or end of the pattern?  Some may say that the most stress is in the latter half of the pattern after the triangles, and by that point, about half the fuel/weight or more is gone. When it comes to the idea of fairness or who has an advantage, I would say it is all in the electric court. They can build a model that weighs the same and balances the same throughout the flight. I think that would kind of "balance" against having to pull a few pounds more. Some where in the concept of trying to get an electric model weight down to where you can use smaller diameter lines is the right size/wing area/wing loading to achieve that. The answer to that question may lay entirely in a new model design to best use the consistent dead weight that is the electric power plant. So far, most people are just converting existing design with slight modification to mount the equipment. With as much success that the electric stunt model has had, I feel that there is no disadvantage to the extra weight. You just have to learn to work with what you have and design an air frame to give you want you want, not just "build a lighter model." I hope that makes sense.
    Type at you later,
   Dan "Gimme My Nitro" McEntee

My 60s sized  ships  use  just under 5 ounces for the  VECTRA  and  just over 5 ounces  for the KATANA , average that weight it is  2.1/2  ounce . I think t s funny so many people think we all are using  7 to 8 1/2 ounces of fuel,  and some want to add a minimum of 6 ounces to your  IC plane?
I agree  if we fly the  2 type planes together  the field should be level,  HOWEVER  as I have been told  by several people flying Electric,  they have a  huge set of advantages over  IC  as it stands  now.

Like the advantage to start the motor and the pattern,  Big one for Electric

Run time,  big advantage when you can get every flight almost to the second, advantage electric

Program the computer controlled motor to help you with certain maneuvers, like a burp, followed by 5 seconds of FULl Blast power to increase the speed to help with placing the plane better where you want it on landings.

Being able to programs in more or less simulated 4/2 break  instantly.

Being able to have the motor shut itself down automatically if you hit  the  prop on the  ground on takeoff

There are several more  but the point is made, and not to mention being able  to get much more practice at many more sites.  And  there is  NO telling  what else people will be  doing  in the future ,with computer controls to help fly your maneuvers

 I develop, sell, planes and equipment for both systems, and  I would  not want  one to have more advantages over  the other, no matter  what is motivating the plane.  In my mind all is  NOT level  now.

Randy

[Brett Buck]

I agree  if we fly the  2 type planes together  the field should be level,  HOWEVER  as I have been told  by several people flying Electric,  they have a  huge set of advantages over  IC  as it stands  now.

Like the advantage to start the motor and the pattern,  Big one for Electric

Run time,  big advantage when you can get every flight almost to the second, advantage electric

Program the computer controlled motor to help you with certain maneuvers, like a burp, followed by 5 seconds of FULl Blast power to increase the speed to help with placing the plane better where you want it on landings.

Being able to programs in more or less simulated 4/2 break  instantly.

Being able to have the motor shut itself down automatically if you hit  the  prop on the  ground on takeoff

     I more-or-less agree with this assessment, and to me it is clear that the advantage will grow with time and experience. We have about 70 years of IC engine experience, and 30 with the definitive and probably final configuration. They are more-or-less optimized at this point and at least a fair number of people are able to achieve nearly ideal performance most of the time.

    Having said all that, I still think that IC in perfect shape has advantages over electric in the current state of development in a few conditions, specifically, heavy but smooth wind. Electric has advantage in most other conditions, particularly light to dead air, or light turbulent air.

      I don't think the rules should drive you to a solution, but at the  same time, if something its better, it's better, and trying to change the rules to even up the odds by favoring one over the other is something I wouldn't have much enthusiasm for. Electric is not the sort of leap forward that happened when we went from ST60s and the like to tuned pipes, and we didn't change the rules to try to help them keep up (or as Windy suggested, start a different event to separate them out).

       The issues discussed here are really just about feeling aggrieved, with some justification, but don't make any difference from a competitive or engineering standpoint. It's not really worth fixing, but by the same token it doesn't hurt anything if they are "fixed".

     The line size requirements don't make a lot of sense a long as we are weighing the models and pulling 10gs. and if we can, we should get rid of them. Last time I broached the subject, I was told they would never go away, but maybe that has changed.

     Brett

[roy cherry]

good morning  i have been following this thread as i wait for ome weather to go testing my latest model  i fly f a i so if you pass the pull test you can use any size line you care to but what  causes me some concern is that only oficciall flights are pulled for a pull test to be valid every flight at a contest ought to be pulled including all test and practist flights if their are any safty concerns  other wise to me it seems pointless        roy   

[RandySmith]

As I wrote  earlier, I think this is  much ado about  nothing,  just let  people pull 10 gs  and  run whatever lines they want, as long as they test OK
Simple solution, it will  work, and  gets us past calling  IC guys bullies, and  insinuating they are liars , that  we DO NOT need, and  does  not serve  us well

Randy

[frank williams]

Without a doubt this is a simplest and best solution to the problem at hand.  10g pull only.

[frank williams]

I disagree.  In general people are smarter than you think.  FAI flyers don't seem to have a problem.

[RandySmith]

I disagree.  In general people are smarter than you think.  FAI flyers don't seem to have a problem.

Yep  this is right the rest of the world has been doing this for many years, and you will not find anyone flying a 64 ounce ship on 008s, I think  you would be  hard pressed to find one flying on 012s,   Even  015s  are  lines I personally would not use on a  64 ounce  60 sze ship, too spongy, better control and feel  is  much more important  than the .003 difference, and if you have to , you can run 014 solids. 
I do not think  008s  would even  pass the 10 G  pull test,  and  if you are doing 10 G pull test, then your lines break while flying pulling 3 Gs, something  else seems  wrong

Randy

[Dave_Trible]

In all my time in this sport, the very few failures I’ve seen were all, save one, were where the wire got damaged,  mostly where the ends were made by either working back and forth at a hard point where the cable exits the ferrule or a kink.  The only other failure was a brand new set of Sullivan’s from years ago shredded in the middle on the first flight- an obvious flaw in the cable.  The line weight really wouldn’t have mattered very much other than the heavier line will hold with more damage not yet seen.  Line condition I think is more important than weight.  You can only hope a pull test will find the weak point on the ground.

Dave

[Steve Helmick]

Brett you may not be aware of this per your comment but Gsump lines have been submitted by Tom Hampshire for a rule change to allow for the use in CLPA on 5/2/18. Proposal and initial vote links. Looks like it passed initial vote 6 to 5.  https://www.modelaircraft.org/files/CLA19-02.pdf  https://www.modelaircraft.org/files/CLAerobatics2018InitialVoteResults.pdf    Dennis Adamisin, Bob Hunt, Phil Cartier, and Frank Williams also signed the proposal.

"Gsump lines"?  I assume you mean Spectra or MicroDeema fishing lines, but I've never heard those referred to as "Gsump". I have not tried either, but I know there is some information in the AMA rulez about how they are to be fastened at the end....but there have been reports that it doesn't work. I figured that there would need to be some improvements in the rules there before further applications would be allowed. But maybe I figured wrongly.    Steve

[mike londke]

I apologize for posting bad info. I didn’t look at the date close enough. It appears this proposal was dropped. So I deleted the post.