Conference vmszoo::rc

>    How cold can it be and still have your high start
>    work? (surgical tubing) I am sure someone does use 
>    there glider in the winter months. 

They work fine in the winter - the only real change
is they stay clean on the snow instead of laying in the dirt
all day.

>    Another question , How do you keep your reciever 
>    batteries warm? Keep them in your pocket and install 
>    them at launch time??

I don't - they work fine cold - just not as much capacity.
If you get 2 hours on your packs in the summer you should
get 1.5 hours on a real cold day.  BUT - never hurts to check
the voltage under load to be sure.  BUT when it's really
cold you tend to fly less - got to hop in the car and warm
up!

Bye          --+--
Kay R. Fisher  |
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    I've had minor problems with a heavy duty high start in the winter. I
    found that if it was laying in the snow, which it often would be here
    in Colorado, and I was trying to launch a 100 inch Sig Riser 100, the
    rubber had lost too much elasticity(sp?) to get the plane up.
    
    A funny
    thing happens too, the plane rises about 30 feet or so and then the
    high start would die for a moment, until the rubber warmed up from the
    sun, then it would rise another 30 feet or so. This woud go on until
    you reached the limit of the high start. The tough part was keeping the
    plane pointing up while the rubber warmed up. Caused some tense
    moments! 
    
    Now I never had this problem with my Gentle lady, It was much lighter
    and didn't put much strain on the high start. Kay, have you ever had
    this problem, I wonder if it might have something to do with the
    altitude as well as the cold??

>    and didn't put much strain on the high start. Kay, have you ever had
>    this problem, I wonder if it might have something to do with the
>    altitude as well as the cold??

No - and I hope to hi-start a Lovesong this winter if Santa is good
to me and my Visions materialize (pun intended).

Bye          --+--
Kay R. Fisher  |
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================================================================================

I too have had a problem in the cold weather with the high start. It just
doesn't seem to give back the energy that you put into it when you stretch it.
Worse yet, thermals are real tough to find.

I too had some trouble with a cold High-Start launching a gentle lady (this past 
weekend). The temperature was in the low 40's (maybe cooler at ground level).
The symptom was loss of elasticity of the surgical tubing, resulting in less
than 100 feet worth of height!  Simply holding a piece of the tubing in my
(warm) hand caused it to shrink quickly!  I brought it in inside, unwound it off
the spool and watched as it slowly gained its elasticity back.

Could there be a difference in the manufacturing of the tubing?
Lawton Read

    Lawton,
    
    I too have found that high start launches are pretty anemic in the
    winter. That's one of the reasons I don't fly much in the winter. (The
    cold is the other reason.)
    
    However, I also think the type of rubber might have something to do
    with it. I plan to get in at least one flight in the cold weather to
    check  out the performance of the rubber I use now.
    
    Dave
    

    Rubber *DOES* change properites with temperature.  In fact, if you
    take a piece of this tubing, drop it in liquid Nitrogen, the rubber
    will "freeze" up so hard that it shatters like glass when struck
    with a hammer!

                       _____
                      |     \
                      |      \                          Silent POWER!
      _        ___________    _________   |            Happy Landings!
     | \      |           |  |         |  |
     |--------|-  SANYO  + ]-|  ASTRO  |--|              - Dan Miner
     |_/      |___________|  |_________|  |
                      |       /           |     " The Earth needs more OZONE,
                      |      /                       not Castor Oil!! "    
                      |_____/

Anyone know what temperature surgical rubber becomes in-elastic? Is it a rapid 
drop at some temperature or a slow decay over a range of temperatures?

RE .7 Liquid Nitrogen - Too cold for me! The molecules aren't moving enough!

I know the low 40's renders mine totally useless and thought it might be useful
to know what temperature I *really* should be flying in.

Thanks,
Lawton Read

    Re: last several,
    
    Sounds to me like an electric winch would be the logical way to go for
    winter glider guiding if you don't want to simply hang it up 'til
    warmer weather.
						 __
				|      |        / |\	   	       
      	         \|/		|______|__(o/--/  | \	   	       
      | |        00	       <|  ~~~  ____ 04 ---- | --------------------
    |_|_|        (O>o		|\)____/___|\_____|_/	   Adios amigos, Al
      |     \__(O_\_	        |	  |___/	 o	   (The Desert Rat)

I've had my hi-starts out on the snow and ice and although I wouldn't say
they didn't loose some power - I don't remember a drastic loss.

Besides - the pull of the rubber is only 1/3 of the launch power.
The other 2/3's comes from the wind.  I've windy had days where I would
stretch the hi-start out as far as I dared and when I let go of the
sailplane it would stretch it out another 50-75 feet behind me.  Good
wind - good launch, weak wind = weak launch.

My Up-Start is from Dyna-Flite and my Hi-Start is from Airtronics (heavy duty).

They are both pretty worn out and should be replaced this winter since
I plan to launch a Lovesong with the Hi-Start.

Bye          --+--
Kay R. Fisher  |
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    Kay,
    	I've always wondered why someone doesn't double up the rubber
    on a highstart.
                       rubber
    ================================o             line
                                     -----------------------------
    ================================o                   
                       rubber
    
    
    
    
    Any ideas why?
    
    
    Tom
    
    P.S.
    	Could you suggest a good winter glider?
    
    

    A good winter glider? a dark and durable one ;^)
    
    With good rubber, doubling would be too much tension and you wouldn't
    get the stretch out of it. This would fold a lot of wings too. If we do 
    see a lot of loss in power in the  rubber, that might help. I was
    figuring on getting a full size hi-start for next season since I'll be
    getting into the larger gliders. That might make a good HLS hi-start in
    those winter days and go back to the lighter rubber once it warms back up.
    
    You want durable since you'll probably be landing in a crusty field with 
    lots of "pothole" foot prints with nose grabbing edges. I guess what you 
    need is a beater plane. I'm hoping to give it a try this year too.

I have doubled up the rubber on the histart. There's nothing wrong with that
But it's just easier to get a bigger diameter tubing, which I've found to be 
MUCH more durable.

>                   <<< Note 1123.11 by SA1794::TENEROWICZT >>>
>
>    Kay,
>    	I've always wondered why someone doesn't double up the rubber
>    on a highstart.
>                       rubber
>    ================================o             line
>                                     -----------------------------
>    ================================o                   
>                       rubber
>
>    Any ideas why?

How about it doubles the chances of getting hung up on weeds, doubles
the chances of breaks, gets tangled up in knots, etc.

Just get a larger diameter.

>    P.S.
>    	Could you suggest a good winter glider?

Interesting question.

What material has the best chance on not cracking on a hard landing
at freezing temps?  I assume that the plastics (like the Hobby Lobby
UHU's would crack to easy.  Is fiberglass better than wood in the cold?
I would guess - balsa would be best.

Easiest to launch would be some sort of electric.    

It's not that the hi-start is too wimpy - it is because it is too darn
cold to be spending a long time stringing it out and wrapping it up again.

So I would say a simple balsa electric - Goldberg Electra, Thermal Charger.

What kind of covering would be best?  I would think a cloth like super
shrink coverite would be better than a plastic like MonoKote.

I think for winter flying you should avoid high performance or critical
stuff - that would rule out Sagitta's and Astro Challengers.  You want
a simple flat bottom slow airfoil - be cause you're hands will be cold
and you won't have nearly the "good thumbs" you had during the summer.
Also - I would worry about the Challenger class of planes because if you
don't keep close attention and hold them back from any dives or sudden
changes in pitch they will fold a wing (just ask Dan Miner).

I don't like the hassle of the V-tail on the Thermal Charger.  I don't
like the idea of fiddling with rubber bands to put the wing on with
the Electra.  Anybody else have suggestions?

Bye          --+--
Kay R. Fisher  |
---------------O---------------
################################################################################

    You could go with something like a Gentle lady with the big durable
    fuselage and use nylon bolts to hold on the wing. Speaking of which, what 
    happens to the nylon bolts in the cold? Do they become brittle in the cold 
    also? Enough to be concerned? Gentle Ladies are reasonably cheap and
    you can build one in a weekend if you really crank it out. Lots of room
    for standard size gear and reasonable performance in the stock 
    configuration.

    Re: .-1, Jim,
    
    You bet'cha!  Anything made of nylon becomes brittle in the cold.  Of
    particular interest to us RC'ers are such things as wing-bolts and
    nylon clevises.
    
    Is this a concern...well, it sure _could_ be.  Nylon bolts that are
    overtightened just a little can pop the heads off, either when you
    tighten them or under flight loads.  Clevises can also fail under load
    by having the pin snap off or, when prying apart to make an adjustment,
    the side-arm can snap.  I've had all of these possibilities occur to me
    at one time or another, fortunately never at the expense of an
    airplane, and I _KNOW_ it's a lot less frigid here than where most of
    y'all will be winter flying.
    
    Is there a defense??  I'm not sure but I believe boiling all nylon
    hardware restores moisture content and makes them more flexible/resilient
    to the ravages of the cold.  Alternatively, you could replace all nylon
    parts with metal but you'll still [most likely] have nylon horns which
    are also susceptible to breaking in the cold if stressed.  I think just
    a little care and awareness not to bump or unnecessarily stress nylon
    parts is probably all the precaution needed but boil all parts that you
    can, most especially nylon props which can easily shed a blade in the
    cold.  Frankly, I would recommend against using nylon props in the
    winter for that reason.
						 __
				|      |        / |\	   	       
      	         \|/		|______|__(o/--/  | \	   	       
      | |        00	       <|  ~~~  ____ 04 ---- | --------------------
    |_|_|        (O>o		|\)____/___|\_____|_/	   Adios amigos, Al
      |     \__(O_\_	        |	  |___/	 o	   (The Desert Rat)

    I'll have a winter glider this year, too.  A Sophisticated Lady with a
    Graupner Speed 500 in the nose (it _was_ way too sharp for AMA rules
    anyway, so I cut it off and stuck a motor in there!), 7.2V battery and
    (print/no_desert_rat_terminals) a Graupner on-off with BEC.
    (print/even_desert_rat_terminals).
    
    We'll see how it goes, though if the weather stays like it is now
    (unlikely) even the back-easters will have that fly 9 months, build 3
    months year that Al is always bragging about! :^)
    
                           __|__                              Regards-
    \________________________O________________________/       Frank.    

    

    Last winter I flew alot with my (ex-) GRAUPNER CIRRUS with a engine
    gondola (?) on the top of the fuse and an installed ENYA 09. Even I
    knew that the CIRRUS fuse would be very critical in the cold I never
    had any problems landing in fresh powder or on ice. Since in wintertime
    you fly in calm air anyway there shouldn't be any problem with landing.
    
    I know that an engine on a glider is not the real thing but consider that
    you won't see the engine anymore once it reached a certain altitude.
    I remember someone saying "would you fly with spoilers out ?" regarding
    the prop consider this one : would you get 20 minutes + with spoilers
    out and just 2 minutes engine runtime ? 
    
    I'm looking forward already to this year's winterflying. Imagine - dark
    blue sky, soft snow that reflects the sunlight and enlightens the
    underside of your bright white 3m Sailplane ....maybe this weekend,
    forcast said something about snow. 
    
    
    
    Holm- und Rippenbruch,  Bernd 
     

    I flew a number of times last winter with my (heavily) modified Electra.
    No problems.  I have a couple of packs, and I just charge 'em all before
    I go out.  Dead air flight of 10 to 15 minutes are normal, and it only
    takes a minute to change a pack and go up again, and you don't need to
    worry so much about overheating the motor, so you can over-prop it and
    get better climb performance.

    It's much easier than stomping across a field to try and pound a
    highstart anchor into the frozen tundra.  You can fly right away, and
    when you (or your companion) start to feel the cold, there's no clean up
    or retrieval needed to pack it in.


    Also, Re: Boiling Nylon.  This does add moisture, but, wouldn't you
    think that in freezing weather, this would have a negative effect on
    flexability?

    One advantage to flying electrics in the winter is that you can use the
    hot battery pack to warm your frozen hands after each flight.  They
    start much easier than gas jobs also.  No fiddling with the needle in
    the frozen air prop blast either.  I flew my Eclipse electric last
    weekend inbetween raindrops and it was a little boring compared to a
    Panic at full bore.  I stretched things and managed three consecutive
    loops.  Big deal.  I think I'll save this plane for days when my
    reflexes need a break.
    
    Charlie