[NSRCA-discussion] Off topic, nothing like a crash to keep us humble

[Fred Huber]

When a CL plane consistantly has the line go slack when going inverted... 
there's a setup issue.

Probably  not lateral ballance
Probably not thrust angle.  (right/left angle)
Probably not rudder.
Probably not the lead-out location at the wingtip

Those all affect line tension the same upright or inverted.

Too much down thrust can cause the lines to go slack when you go inverted... 
it requires being off a lot though.

Engine torque with the normal direction crcle (upright) wants to turn the 
plane inward... but invert the plane and the tourque should make the plane 
pull out harder.

That leaves the most likely candidate as an offset of the flaps relative to 
each other.  (since the Nobler has flaps and elevator) If when upright the 
offset is holding the plane out, that would cause it ro roll in when 
inverted.  If the plane looks like the wingtip is drooping outboard when 
upright, there's likely to be an issue with the flaps causing an outboard 
roll... and inverted is a bad idea. (even though the line tension will be 
very good upright)  I always wanted my wings to look like they were a 
straight extension of the control lines (and my arm) in level flight.

Timing of when you change from upright to inverted will only momentarilly 
slacken the lines, and a well set up CL plane, you have to have significant 
wind to have a problem.  Excessivly far back lead out position, if the lines 
go slack, when they tighten up, the jerk can snap the stranded steel control 
lines. (but its harder to get them to go slack if the lead out position is 
further back than needed...)  I generally set mine up such that if there was 
no wind the line pull was slightly more than the aircraft weight, using just 
enough wingtip weight to compensate for line weight, then adjusting lead-out 
position at the wingtip. (for test flight... hang by the lines and the nose 
of the plane needs to point down)

I found that if the lines went slack... backing off wasn't the cure.  I flew 
with my arm fully extended pointing at the plane.  if the lines slacked, I 
would turn faster, leading the plane, which effectively shortens the lines 
AND "whips" the plane forward.  By timeing the whip in relation tothe wind 
1/2 A planes on appx 20 to 25 ft line could fly for several minutes after 
the engine quit this way.  Larger models on long lines, you can extend the 
glide by half a lap or more.

----- Original Message ----- 
From: "Pat Hewitt" <phewitt at farmersagent.com>
To: "NSRCA Mailing List" <nsrca-discussion at lists.nsrca.org>
Sent: Monday, October 09, 2006 11:21 AM
Subject: Re: [NSRCA-discussion] Off topic, nothing like a crash to keep us 
humble


> May be you will put some loc tite on that nut next time HEHEHEHE that was 
> a
> good story I am sure a lot of us have done the same thing
>
>
> Pat
>
> ------ Original Message ------
> Received: 11:13 AM CDT, 10/09/2006
> From: Bob Kane <getterflash at yahoo.com>
> To: nsrca-discussion at lists.nsrca.org
> Subject: [NSRCA-discussion] Off topic, nothing like a crash to keep us 
> humble
>
> Now that the season is finished (at least up here in
> the soon to be great white north), I am making some
> cosmetic repairs to my Temptation. For a little change
> of pace, I decided to test fly my Top Flite Nobler ARF
> CL plane on Saturday.  CL you say? Yup, this is yet
> another facet of the hobby I wanted to revive from my
> youth. The last time I flew a control line plane was
> about 1977, and then nothing bigger than 1/2A. I
> picked up the Nobler and then spent two years putting
> together at somewhat of a leisurely pace.
>
> First flight, engine running too rich . .take off . .
> . try a little up and down . .  hmmm, not very
> responsive. I was expecting it to be twitchy, after
> all this is a "real" stunt ship. Did a loop or two,
> ran it out fuel.
>
> Second flight, leaned the engine a little, but still
> too rich. Plane is still pretty unresponsive. Some
> more loops . . . let's try inverted. Oh-oh . . .
> lines are slack . . .  plane heading for the ground .
> . .  I back up sharply and the plane pulls out with
> inches to spare . . .  back to upright flight, run it
> out of fuel. My mentor suggests I pay attention to
> where the plane is relative to wind direction when
> doing maneuver, I had picked the absolutely worst part
> of the circle to try and go inverted. OK, tuck that
> one in the experience drawer.
>
> Third flight, lean the engine some more, but
> apparently still not enough. More level laps, couple
> of loops, let's try inverted again. Oh-oh, thought I
> picked the right part of the circle to start but now
> it's not looking good. Lines going slack again, I back
> up . .   plane starts to recover so I think I have it
> and stop backing up. Plane continues at a 30 degree
> downline until the Earth jumps up and grabs it.
> Crunch!!!! . . . followed by silence. Heavens to
> Betsy, I crashed my Nobler. Could not blame this one
> on frequency control, just a loose "Nut" on the
> handle.
>
> The short flights were fun, and I will probably try
> this again.
>
> OK, back to Pattern.
>
>
>
> Bob Kane
> getterflash at yahoo.com
>
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