Conference vmszoo::rc

>                     <<< Note 1289.0 by ASABET::CAVANAGH >>>
>                         -< House of Balsa 2x4 glider >-
...
>    o Wing span 49 1/2 inches
>    o Wing area 409 sq. inches
>    o Weight with standard radio 28 oz.
>    o Wing loading 9.8 oz./sq. ft.

9 oz/sq ft is just right to heavy for a 2 meter glider.
It is way too heavy for a 49" glider.

If you plane to use it to slope soar at Bose - it is probably
the perfect weight.  If you also want to thermal with it then
at least make no compromises on weight with the radio installation.
That is use the new Airtronics or RCD micro receiver and micro
servos and a 1/2 size battery (200-300 mah).

I've read some recent reports on the usenet that the 2x4 is a lead
sled.  Others of course defend it and say the wing it built like
a battle ship.  All agree that the 2x6 has a better wing loading
for thermal soaring.

Soooooooo

Think Bose.
Think light.

Remember - this is just my opinion - I have never seen a 2x4 fly.

Bye          --+--
Kay R. Fisher  |
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I have a very modified 2x4.  I first flew it stock off a high
start, and true, it is a lead sled.  But the only thing I could
compare it to was a Gentle Lady, which is in a whole different
class.  The 2z4 wouldn't float in light air, and in the winds it
needed to be heavily ballasted just to hover, least of all make
headway.  Real thrilling.

Anyway, after flying it off and on for a year or so it became
apparent that it needed some doctoring.  The model is very tail
heavy, so the first thing I did was to cut down the tail end from
the back of the wing to the end of the fuse.  I took a grinder to
it (literally) and knocked off enough of the tail arm to make it
look like a pod-and-boom job.  I recommend this, maybe to a
lesser extent.  But you will need to get lots of weight out of
the tail.  I also went over the tail surfaces and pared every
gram I could, even to the extent of subsituting the nylon control
horn and clevises with a short piece of paper clip into a wooden
horn.  Again, I recommend this.

But that didn't cut the mustard; it was still tail heavy.  So I
added about 3 inches to the nose.  This allowed me to move the
radio and battery up, and now it balances with just a little
weight in the nose.  All of this is something like the Monty
Python bit about making a budgie out of a cat.

The wing is indeed strong.  I used it for the test flights of my
cardboard Quik Stik planes, and it proved a very nice wing to get
those first flights on.  Its pretty beat up now, and I am
thinking of resurrecting it for use as a slope wing.  However,
during my mods I built a new wing, made of the outer panels of a
HOB 2-T glider (can you say bow-wow?), mated to a home-brew
center section. The span is now around 60 inches.  I've only
flown it once like that, and in the Coleraddy winds it hovered
just fine(!). Anyway, there it sits.

One reason why it sits is that the only radio I could fit into it
was a Tower micro system.  At that I wound up putting the servos,
radio, and battery in separate compartments.  I haven't
dared turn on the Tower radio since last Spring when the Last
Great Rebuild of the Six Million Dollar Eaglet crashed from a
radio hit.

So, more than you ever wanted to know about the 2x4, maybe you
can give some kid a good deal on it and get yourself a Gentle
Lady.  I will give it this: the kit is first rate.

  For Sale:  A brand new 2x4 glider


  8^)


  Really though...thanks for the input.  This sounds like a challenge!  I'll
have to see what mods I can put into it to make something out of it.  For
$17 it's worth a try.

  I'll keep you informed.


                  Jim

  What would be a desirable wing loading for this plane?

           Jim

    Depends on what you want to do. What they project is probably fine for
    Bose but you'd want lighter for Acton. Lighten the tail as much as
    possible and go with micro servos/batteries should help. Coming out and
    having fun with us at lunch in Acton should be fine, you've just got to
    set your expectations properly and not expect to compete at CMRCM with
    it at the glider fun-flys. I replaced the tail longerons with tristock
    on one plane to cut weight and that worked out pretty well. CA should
    help too.
    
    Make patterns of everything and build it stock. Then you can build a
    second fuselage later when you figure out the weak spots and thin it
    down. 

  Re: -1

  Good point.  What I'll do is - make the patterns of the parts for 2x4 Mk II
and while I'm building the stock kit I'll try to reduce the weight where 
possible without major structural changes.  That way I can get into the air
faster than doing a major modification.


              Jim

    I bought a used 2X4 a month ago from John Lavery as an adjunct to
    another purchase.  Last Sunday I thought the winds too strong and 
    gusty for my 0.090 powered Gentle Lady, so I flew the Gentle Lady
    body with the stubby 2X4 wing.  Worked like a charm.

  Maybe I live a secluded life, but this is the first time I've come across
a plane that utilizes 1/2 of the elevator.  Only one side is used, the other
is just part of the horizontal stab.

  Does this affect flying characteristics?  ie: does it cause a bit of a 
roll?

                Jim

    I've seen one other standard class glider with only half an elevator.
    Seemed to work fine. If your not comfortable with it, it should be
    easy enough to modify. For slope flying, you might want to consider a
    full elevator.
    
    Steve

>a plane that utilizes 1/2 of the elevator.  Only one side is used, the other
>is just part of the horizontal stab.

I wouldn't worry about it.  In fact this technique may offer you some
opportunity to decrease weight.  In my old Drifter II it had a split
elevator and most of my early repairs were related to it breaking.
Eventually I put music wire between the halves (much heavier).

When it did break it did not seem to change the flying characteristics
significantly.

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

    The Mark's Model Mirage (100" or 112") uses only 1/2 the elevator
    for control.  My father built this model in 112" span and it flies
    fine.  When the slopes I fly are working well(ie wind @ 90 degrees
    to the hill) most thermal type gliders will fly acceptably well.
    The only one I have built that wouldn't was the Pierce-Aero Ridge
    Rat.  My father is currently building a 2-meter glider called the
    Mini-max(you may have seen it advertised in Model Aviation).  The
    kit manufacturer claims a wing loading of less than 4 oz./sq.ft.
    The model has over 700 square inches of wing and a claimed flying
    weight of 19 oz.  The light weight is achieved by substituting
    lighter balsa stock, for instance the wing D-tube is sheeted with
    1/32" balsa instead of the typical 1/16", the spars are balsa
    instead of spruce, micro servos and receiver, etc.  The manufacturer
    recommends using solar span(available from HOB) for covering.  I
    feel you can substantially lighten the 2x4 by using similar
    building techniques, without seriously compromising the strength.
    
    
                                                   Good luck,
    
                                                   Jim                        

  Actually that's about what I have done.

  I took the ply sides and bulkheads and used them as templates for 3/32
balsa replacement parts.  I used some 1/4 x 3/8 balsa to make new framework
bulkheads/formers.  I am also using the 3/32 for the sheeting instead of
the ply which is used on the bottom of the fuse.  The only place that I
will still use ply on is the area where the tow hook is installed.

  Right now I have the fuse 80% completed and it weighs MUCH less than
the materials supplied for the fuse (and that doesn't include all of the
original materials...just the major ply parts).

  So I think I will get this brick down to a reasonable weight.  If it
turns out too weak for a high start....well I still have the templates!!



           Jim

  Well a new personal record has been set.  With only about 14 hours of
actual building time put into it (that includes the scratch building of
the fuse to reduce weight) the 2x4 is pretty much ready for covering!
  I will have to build a second wing (this one is stock) at some point
in order to get the weight down to a reasonable level.  I figure this
wing (made of cast iron) should be good for slope soaring (if I ever try
it) and windy days in general.  Using the stock wing also reduced my
building time substantially.  I think I can easily reduce the weight
of the wing by 1/3 by using lighter materials and eliminating some of
the structural overkill.
  I hope to have it covered this weekend. 


  
                           Jim

    I used to have a 2X4 that I flew off of the slope at Cal State Hayward.
    
    We used to occasionally get very strong winds that would make flying 
    most flat bottom airfoils impossible.  
    
    Then I tried somthing that made my 2X4 flyable in 30 MPH winds without
    adding ballast!  Take a piece of Carl Goldberg trim tape 1/8 of an inch
    wide and run it the length of the wing between the leading edge and the
    first turbulator spar and the length of the wind be tween the first and 
    second turbulator spar.
    
    It will kill your thermal performance but it will penetrate very strong
    winds without adding weight.
    
    Will