Lines for .061s

Keith Trostle and I were chatting about small planes, and he suggested a rule change to allow .008 cable on up to .061 for aerobatic competition only (not speed, scale, etc.).

Currently, you can use .008 solid lines, but you must use .012 cable, a 50% drag penalty, and 100% weight penalty. And you only have 20% more power output to carry it.

I agree with Keith.

What do you guys think?

I'd be inclined to say no. If for no other reason that you big 061 bullies keep trying to beat up on my poor little Medallion 049.
But if you can show that the strength of 008 braided compairs with (mass,centrifugal force ,etc) a 40 size engine on 015 braided, then go for it.

Sounds good to me. What would the pull test be?

Yeah, well, John, when we come close to beating you, then you should worry. Don't forget, I get that trophy back at the Palmer meet to give to the next guy.

I ran some calcs and came up with:

.061, 15 oz, 50' lines, 4 sec laps = 3.6 lb pull

.049, 10.5 oz, 42' lines, 3.7 sec laps = 2.5 lb pull

There is a big difference, but I doubt that 3.6 lb is going to be a problem.

The guideline for pull-testing is 100 lb/cu.in. displacement. So it would be 6 lb and 5 lb respectively.

I think it's 15 pounds (or was it 12?) for 1/2-A Combat. I'll have to go look.

Of course it sounds great to me. My problem is that the 1/2a competition we fly around here is an "honest" 1/2a, so we are limited to 051 and under (wasn't 051 actually "A".

The force on the lines is nominally =mV^2/r. You can rewrite this (ignoring a few "pi's") as = mr/t^2, where m is the mass of the plane, r is the line length (radius), v the velocity, and t the lap time. So compare the lap time for 35 foot lines (old typical 1/2a) to 42 or even 52 foot lines for new 1/2a and see what you get.

I do not know the original criteria for line sizes. It is pretty clear to me that the newer engines allow heavier or bigger planes, but we fly on longer lines.

>My problem is that the 1/2a
>competition we fly around here is an "honest" 1/2a, so we
>are limited to 051 and under.

Hmmm. I would have said an honest 1/2A was less than 0.50

"NO" To much BS about rules are going around now.

Scott(just made four sets of .008)Riese

Yesh.. the Tee Dee .061 was invented so that Free Flight folks could fly the same airplane in both 1/2-A and A by just changing the engine. It won't make sense in other classes of competition - an .051 would be eaten alive by a .19 in "A" speed, for instance.

I think some areas allow the .051 because it was designed to have the same power as the .049 (I read that someplace).

I believe the .061 is mostly for Leprechaun stunt, although a few posts awhile back have indicated that some areas are pushing to allow .061's in 1/2 A.

Personal opinion - keep 'em separate.

George

Going to .061s for our so called 1/2A stunt events makes sense. There is a whole world out there that is making 1cc (.061cc) motors.

>Keith Trostle and I were chatting about small planes, and he
>suggested a rule change to allow .008 cable on up to .061
>for aerobatic competition only (not speed, scale, etc.).
>
>Currently, you can use .008 solid lines, but you must use
>.012 cable, a 50% drag penalty, and 100% weight penalty.
>And you only have 20% more power output to carry it.
>
>I agree with Keith.
>
>What do you guys think?
>
>Larry

Hi Larry ...and the rest of Youse Guys...Your query is about the line
specification for .061cu" displacement, right? You are not asking
to allow .061cu" engines in 1/2a Stunt events are you? the specs for
1/2A displacement is clear enough to me....a .061 is not a 1/2A ....
It's a small "A" engine....I vote NO for a displacement increase..and
Yes to the line spec change for up to .061cu" engines.
Thanks; Tony

The British had more sense. They call 1/2A up to an 09.Truly makes life simpler.

Hey, it's an unofficial event, right? So all you need to do, as a CD, is specify that .061s are allowed. Who cares what everyone else does? Line sizes are another matter, of course..

Yes, let me make it clear that I am not advocating raising 1/2A to .061 size, only allowing .008 cable to be used with aerobatic planes with that size engine. .008 solids are allowed up to .15 size, and believe me, there are some HOT .15s out there!

Heh heh heh.. I wonder what Larry Scarinzi was using with that Scared (er, Sacred) Kitten..

OK Cub .14?

I think someone said Picco.