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Author Topic: 15 lines  (Read 6732 times)

Offline bob whitney

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15 lines
« on: October 11, 2016, 06:39:44 PM »


  what size lines for 15 profile
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Offline Bob Heywood

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Re: 15 lines
« Reply #1 on: October 11, 2016, 06:50:20 PM »
.015 (2-Line) or .012 (3-Line), cable or solid. 52ft - 6in (+0" / -6") center of handle grip to center of plane.
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Offline Ron Duly

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Re: 15 lines
« Reply #2 on: October 12, 2016, 05:44:22 PM »
Just curious where these line sizes came from.  15 Carrier rules are usually referred to as "Denver Rules".  The NCS site shows the line sizes for 15 Carrier as follows:

Flying Lines:
Minimum line diameter:
 Stranded: 0.012 inches
 Solid: 0.010 inches
 Line Length:
 52- - 0" minimum
 52' - 6" maximum
When first proposed, three-line systems were the norm so planes used three .010 or .012 lines as noted above.  No exception was made for two-line systems back then but requiring three-lines was also not specified.  With the advent of 2.4 control systems have 2-line specs been codified somewhere?  I have no problem with the sizes you state but as a CD I'd like to know more.  Thanks 
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Offline Bob Heywood

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Re: 15 lines
« Reply #3 on: October 12, 2016, 07:14:42 PM »
At the 2015 NCS Annual Meeting, held in conjunction with the NATS, the membership voted to adopt the line sizes I specified. In effect, there is now an NCS .15 Navy Carrier event. Unfortunately, our web site has not been updated. I'll talk to Bill Calkins about fixing the .15 rules. In addition to the line sizes NCS also allows electric power with a 2-1/2 lb max weight limit and the use of 2.4 ghz for throttle and hook release. The NCS version is also pretty much in alignment with what John Vlna uses for the Brodak Fly-In.
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Offline Paul Smith

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Re: 15 lines
« Reply #4 on: October 13, 2016, 07:04:35 AM »
The published rules The Brodak were (and maybe still are) simply .012" lines.  This left the door open for two .012" lines with an electronic throttle.

John Vlna has been saying two .015's with electronic, but I'm not sure if it's ever been put in writing.  Two .015's is an advantage over three .012's.  In AMA Rule Book events two line systems operate at a penalty compared to three.
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Offline Burt Brokaw

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Re: 15 lines
« Reply #5 on: October 13, 2016, 08:53:59 AM »
I was at the NCS dinner meeting at the 2015 Nats.  I remember a discussion about formalizing the .15 carrier rules and making it an NCS event.  I also remember Bob Heywood volunteering to write them up and codify and clarify basically what we were already doing in .15 carrier.  I DO NOT REMEMBER ANY DISCUSSION ABOUT CHANGING THE LINE SIZE REQUIREMENT FOR .15 CARRIER.  Furthermore, I do not think it is appropriate for one person to decide to change the line size requirement without input from the NCS membership.  I am totally against increasing the line size requirement to .015 for two line carrier models.  If it aint broke, don't fix it!!!!!!!!   As far as I know there has never been any problem with the .012 lines we have been using.  Most of the carrier flyers have a very difficult time reaching the 70 MPH max speed as it is.  With .015 lines it will slow them down even more.   All of my comments thus far apply to IC models only. 
HOWEVER, with a 2 1/2 lb. max weight for .15 electric carrier models I think .015 lines may be appropriate if only two lines are used due to the high weights that may be used.  But the weight of the IC models is much less than 2 1/2 lbs. so no need for larger lines.
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Offline Bob Heywood

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Re: 15 lines
« Reply #6 on: October 13, 2016, 12:49:24 PM »
Burt, I sent you an e-mail. As a matter of policy I won't debate issues on social media.

However, please review this thread: http://stunthanger.com/smf/carrier/line-size-for-15-profile-carrier/
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Offline john vlna

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Re: 15 lines
« Reply #7 on: October 13, 2016, 02:23:26 PM »
Quote from: Paul Smith on October 13, 2016, 07:04:35 AM
The published rules The Brodak were (and maybe still are) simply .012" lines.  This left the door open for two .012" lines with an electronic throttle.

John Vlna has been saying two .015's with electronic, but I'm not sure if it's ever been put in writing.  Two .015's is an advantage over three .012's.  In AMA Rule Book events two line systems operate at a penalty compared to three.

Paul
Thanks for bringing the Brodak rules to my attention, I will change them to match the NCS agreed lined sizes.
John

PS  I am the only one to use electric at Brodak's so far, I did use .015's however
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Offline john vlna

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Re: 15 lines
« Reply #8 on: October 13, 2016, 02:31:51 PM »
Quote from: Burt Brokaw on October 13, 2016, 08:53:59 AM
I was at the NCS dinner meeting at the 2015 Nats.  I remember a discussion about formalizing the .15 carrier rules and making it an NCS event.  I also remember Bob Heywood volunteering to write them up and codify and clarify basically what we were already doing in .15 carrier.  I DO NOT REMEMBER ANY DISCUSSION ABOUT CHANGING THE LINE SIZE REQUIREMENT FOR .15 CARRIER.  Furthermore, I do not think it is appropriate for one person to decide to change the line size requirement without input from the NCS membership.  I am totally against increasing the line size requirement to .015 for two line carrier models.  If it aint broke, don't fix it!!!!!!!!   As far as I know there has never been any problem with the .012 lines we have been using.  Most of the carrier flyers have a very difficult time reaching the 70 MPH max speed as it is.  With .015 lines it will slow them down even more.   All of my comments thus far apply to IC models only. 
HOWEVER, with a 2 1/2 lb. max weight for .15 electric carrier models I think .015 lines may be appropriate if only two lines are used due to the high weights that may be used.  But the weight of the IC models is much less than 2 1/2 lbs. so no need for larger lines.

Burt
I don't know the date it was discussed, I actually think it was before 2015. Anyway I have flown electric 15 at Muncie for about 5 years or so now, I have always used .015's. If you look at the Brodak rules you will see in the first paragraph I have the lines as .014. Long story but it goes back to before 2.4GHzwas made legal. and was based on a strength analysis done for me by Everett Shoemaker as the minimum that was equivalent to 3 .012 lines.
John
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Offline eric david conley

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Re: 15 lines
« Reply #9 on: October 13, 2016, 03:27:04 PM »
     Oh my, I was also at that meeting in 2014 and although much the same as everyone else, what I took away was just a little different. Cant remember how the topic came up but line size was tossed around quite a bit, some wanting 2-wire lines to be .018s, others wanting .015, and some saying the current rules(?) say .012. We talked about what was going to be used at the NATs (which was to be flown the next day) and I didn't hear of any decision be arrived at other than some were using 3- .012s and others were using 2- .015s. The question was brought forward, "will the NCS put forward the line size to be used in .15 carrier. President Dick Perry asked the question, who wrote the .15 carrier rules? Well I don't remember how that went but I think I heard Denver come up a few times and Dick said something like, "Let who ever wrote the Denver rules make the correction". The reason being, the NCS did not make the rules for the .15 carrier event, just like they didn't make the rules for Skyray or NW sport 40. And to me that is were it was left (hanging there in the air).
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Offline Paul Smith

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Re: 15 lines
« Reply #10 on: October 13, 2016, 08:16:15 PM »
It all depends what your agenda is:

    Giving the advantage to two-line.
    Giving the advantage to three-line.
    Fairness.
    Safety.

Bringing in solid or stranded lines just muddies-up the water.  Better to mandate stranded for all and don't make line-tweaking a part of the competition.

12 x 3 = 36
15 x 2 = 30
18 x 2 = 36

You don't need .018" lines to make it SAFE.  You DO need .018" lines to make it FAIR.



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Paul Smith

Offline JoeJust

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Re: 15 lines
« Reply #11 on: October 14, 2016, 06:00:18 PM »
The designer of the "Denver Rules" was the late Gerry Deneau (sp?).  When I first met him at the 89 Nats he told me that he should have insisted that .15 Carrier should have noted that the planes built for this event were intended to reflect what actually flew off a Carrier ship. Too bad that never happened. Also on .15 Carrier the NW dropped the wording requiring a "profile" body. Not a big deal, but attempts to change that rule here in the NW failed. Electric Carrier in all its phases was not heard of in 89.
Joe
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Offline john vlna

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Re: 15 lines
« Reply #12 on: October 14, 2016, 09:41:19 PM »
I think safety is the main factor in determining line sizes. That said, according to an article by Bill Netzeband from the AAM 1969, the drag difference between 2 .015 and 3 .012 lines is about .03, pretty negligible I would say.
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Offline john vlna

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Re: 15 lines
« Reply #13 on: October 18, 2016, 09:08:44 AM »
I went back and did the line drag calculation for 52 foot line, 3x.012 versus 2x .015, based on the article Control-Line Aerodynamics Made Painless
By Bill Netzeband
Originally published in 'American Modeler', July/August 1966.  http://www.windyurtnowski.com/DaveDay/netze/leadout.htm

Doing the calculation a bit more carefully a .012 line set would have a total drag of about .6lbs
a .015 line set about .8 lbs. So there is no speed advantage to be gained by two lines it would seem. All calculations were done based on 70 mph.
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Offline eric david conley

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Re: 15 lines
« Reply #14 on: October 18, 2016, 12:50:58 PM »
     Thanks John for the info, although I take calculations as a grain of salt, this does enforce what I have always thought about the 3 lines verses the 2 line thing. Just handling the lines as you run them out or wipe them between flight I think how different they feel and then when fly them they are just different. Saying that 3-12s is 36 and 2-15s are only 30 therefor the 30s will be faster doesn't cut it. I've given Burt Brokaw a couple of planes over the years and he immediately takes the 2-wire stuff out of the planes and equips them the 3-wire systems and believe me they are faster and lighter and perform much better.
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Offline john vlna

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Re: 15 lines
« Reply #15 on: October 18, 2016, 10:12:03 PM »
Eric
Yes drag is a funny thing, area alone is not the determining factor. I am not an aerodynamics expert, but Bill was and I think his calculation are correct. I feel as you and Burt do that the smaller 3 lines allow faster speeds over larger 2 line setups. Luckily with electric you can get the power to overcome the drag. I actually have been flying my 15 with slightly larger lines. They are ones I insulated myself before 2.4 was made legal. I find the two lines are so much easier to set up that I'll take the drag penalty.
John
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Offline Ron Duly

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Re: 15 lines
« Reply #16 on: October 24, 2016, 09:49:27 AM »
Thanks for all your input.  So, what is the final answer?  Is the NCS "rule" that two-line 15 planes must use .015 lines?
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Offline john vlna

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Re: 15 lines
« Reply #17 on: October 24, 2016, 12:36:21 PM »
Ron
My understanding is that we agreed to use 2 x .015 on 15 at a meeting in Muncie. That is what I have been doing for at least 4 years now.
John
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Offline Mike Anderson

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Re: 15 lines
« Reply #18 on: October 24, 2016, 01:02:27 PM »
The .15 line size discussion was at the 2015 membership meeting.  The decision was to go to 2 x .015 if a two line system is used.  That was to be implemented upon a vote of the membership.  I don't know if that vote was ever taken or tabulated.  I contacted Dick Perry when this came up last fall, and he confirmed the line sizes and also mentioned that it had not been voted on yet.  I do not know if that has happened yet.  I would have assumed that it would have been resolved before the 2016 meeting, since it did not come up this year.
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