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Conference vmszoo::rc

Title:Welcome To The Radio Control Conference
Notice:dir's in 11, who's who in 4, sales in 6, auctions 19
Moderator:VMSSG::FRIEDRICHS
Created:Tue Jan 13 1987
Last Modified:Thu Jun 05 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:1706
Total number of notes:27193

421.0. "launch part of hand launch gliding" by BRAT::RYDER (perpetually the bewildered beginner) Sat Mar 02 1991 09:01

    
T.RTitleUserPersonal
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421.12 wings, 2 fuselages - mixed and matchedZENDIA::REITHJim Reith DTN 226-6102 - LTN2-1/F02Thu Apr 25 1991 18:1531
    Hi Randy,
    
    Welcome to the fun of HLGs. I did the same thing with a Gnome last
    year. It also makes it so you can get a half hour of flying in in an
    hour lunch ;^)
    
    Sounds like the plane needs to be trimmed a little different to get a
    better lift to drag ratio. Dave Walter and I flew together quite a bit
    last year and I find that we set up our planes opposite each other. I
    tend to trim for thermalling and push down more often and Dave seems to
    like to set his up for a faster glide and slow it down when
    thermalling. Did you put a tow hook on it? A small upstart can get you
    200' up without throwing your arm out and doesn't take much to string
    out/reel in. This gets you out of the ground effect so you can really
    trim it out. Because I trim with more up than Dave, I tend to launch
    shallower and the trim noses me up and Dave tends to throw at about 45
    degrees and get a straighter climb. Use whatever works for you. The
    main thing you're looking for is to launch to altitude and then
    transition into a good glide without stalling.
    
    I too have noticed different HLG performance. Weight had a big effect
    on the Gnome. At 15 ozs it would circle several times from a good hand
    launch. I broke the tail off a couple of times and built a reinforced
    fuselage with a tow hook. At 16 ozs it didn't hand launch as
    impressively as the 15 oz one but it had a tow hook and it thermalled
    wonderfully. The same plane with a S3014 wing (rather than the stock
    thickened E205) moved much faster and had better penetration when flown
    on the slope. The S3014 definitely wanted to be flown faster for the
    same weight (and area, and fuselage, and color P^). I've got a third
    Gnome fuselage in the building queue with the stress being on light
    weight so I get back into "toss for fun" mode.
421.2HLG funKAY::FISHERStop and smell the balsa.Fri Apr 26 1991 16:4994
>               <<< Note 399.709 by DIENTE::OSWALD "TANSTAAFL!" >>>
>                                  -< Thanks >-
>
>Sounds like the answer is simply keep at it - so I will.
>
>Randy

Late reply...

Your launches sound pretty good actually.
You'll find that you get quite a variation in launches
even when you think you do everything right.  Some are pretty
good some not nearly so high.  The over-riding reason
is thermal activity.  A super good launch is your first big
clue with a HLG that you just launched into a thermal.
A super bad launch means your flying in sink air.  Of course
if you stall and/or tail slide because you didn't pitch over
in time that don't count.

Now about that one turn and back again.  
Not bad actually - just keep at it and get a little
braver.  Chase a couple thermals and take a walk to recover
your glider.  But don't get so brave that you get forced into
making down wind landings or it's back to the work shop for you.

Here's something that will help you set goals and measure your
performance.  Measure every flight.  I start my timer just before
I throw.  From experience I know in dead air I get about 30 seconds
of flight time.  In sink air as low as 10-20 seconds.  But
I know if I get 35 seconds or more that there really was a thermal
there and I just wasn't making good efficient turns to catch it.

I was in Acton today and my longest hand launch was 1 minute 10 seconds.
I caught some nice ones off Lamar's Up-Start however and one boomer
was straight up.  I started getting worried about loosing it so
started looping.  The general consensus was that I was still gaining
altitude with every loop!  So I started getting desperate.  Tried
spins (Chup doesn't spin so well) and eventually did some rather harsh
dives into wild fast loops.  In retrospect I wish I had tried outside
loops.

Anyway - HLG's seem to be the highest Fun to Work ratio RC going
and it sounds to me like your just about to start enjoying it.
It does get a bit frustrating (and hard on the arm) to throw and 
throw and throw and never catch a thermal.  But if you go out
several days a week then I almost guarantee in a couple of weeks
one day you will thermal out.  Then the next time will happen sooner,
then eventually you will thermal out nearly once every time you
go flying.  Terry Sweeney says it usually takes him 4 throws to
catch a thermal!

But - measure every flight and you will start to notice more
thermal activity.

I took a fellow with today (Ed Ball) from the facility that has built
many power free flight planes over the years.  He was thrilled and also
passed several interesting hints along to me.

Ed claims that circling in a thermal is not a very efficient thing
to do and if you really want to gain altitude what you want to do
is make a kinda S turn in a thermal then make a U turn back in and 
do another S turn etc.  Sounds awkward and I'm not very good at keeping
the wings level on the Chuperosa but I must admit I tried it today and
spend most of the lunch hour in the air.  If I think I understand the
theory of this efficiency I will attempt to explain it but for now
it seems like magic to me.

He said that as you hit a thermal is instantly shows the plane up
and one wing slows up more than the other.  This causes you to turn
a bit and it feeds on itself - keeping one wing flying too slow
but if you S turn thru a thermal then you are never allowing the
thermal to pack air under one wing and slow it down and when it
might be tending to slow up you left wing you are cycling back to the
right and getting good lift, etc.

I'm sure the quote is not accurate but I welcome experts opinions.

Ed says free flight planes are set to fly almost straight with as slight
turn.  So they hit a thermal and as they slow up their rudder becomes
less effective and their wings take over and they make a slight right
turn thru the entrance to the thermal.  Then they pick up a bit of speed
in the thermal and their rudder makes them turn slightly left and
as the exit the thermal they slow up again and turn slightly right
they they enter free air and resume their normal slight left turn
and circle around and attack the thermal again S turning thru it.
They trim for this effect and if they don't get the S turn to happen
they don't climb nearly so well.

Opinions?

Bye          --+--
Kay R. Fisher  |
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