Conference vmszoo::rc

    I think you had the answer when you mentioned the rubber bands.
    The sudden climb was probably caused by the wing lifting with
    any slight disturbance.  The change in wing incidence will give
    lot's of interesting flight characteristics!  Sounds like
    your problem was weak rubber bands (and possibly not enough
    of them).  I always used 10 to 12 heavy rubber bands, criss-cross
    the last couple to help hold them on.  Replace them as soon as
    any weakness or cracks are detected.  Storing them in a container
    filled with talcum powder helps them last longer.  It absorbs the
    oil that likes to eat rubber.
    	I would rather have the wing held solid and risk more damage
    in a normal crash than take the risk of my wing flying off in normal
    flight.  Those wingless landings are pretty tough!!!  Hope you get
    back in the air soon...
    
    							Bill
                                 
    P.S. I personally prefer nylon bolts.
                                                                      

    
    	Speedy Dry in a can also work well. I concure with bill that
    the problem is probably related to the strength and or number of
    rubber bands used. As a precausion however change the elevator
    servo. If the problem wasn't band related then I would think you
    might have had a serve that was surging while it was seeking
    neutral.
    
    							Tom
    
    	P.S. A secon vote for bolts,Once you can solo

    WOW!!!  10 to 12 bands?   I only use 6 to 8!  As far as nylon bolts,
    I'll have to check into them (as far as mounting).
    
    Thanks guys!

>    PS.  Apparently it took to many sudden jolts because as it was flying
>    level, the wing suddenly left the fuse at about 60ft.  After

I lost my wing last weekend also.  
After I pulled my fuz out of the mud I had worms on the cowl.
Still trying to repair the damage.  

P.S.  Part of the damage is cause the nylon wing bolts ripped their
way out of the wing trailing edge.

Cause of the separation was the plywood that the dowel in the front of
the wing goes into came lose.  I had repaired that a week before
after a crash ripped the wing thru the front of the fuz, and I guess
I didn't do a good enough job.  Landing the fuz is a lot like trying
to fly a bomb.

              _!_
Bye        ----O----
Kay R. Fisher / \
 
==============================================================
    

>    WOW!!!  10 to 12 bands?   I only use 6 to 8!  As far as nylon bolts,
>    I'll have to check into them (as far as mounting).

I use 8 - but I buy them at the hobby shop!  Some rubber bands don't
resist fuel!

              _!_
Bye        ----O----
Kay R. Fisher / \
 
==============================================================

        Re:< Note 162.5 by TALLIS::FISHER "Battery, Mags, & Gas Off!" >

                I initially  built  my  Trainer 40 with wing bolts and no
        band dowels, but  found that every rough landing would wrench the
        fuse apart and finish  that  day's  flying.   The problem is that
        there's no give and the  wing  is  a  lot stringer than the fuse.
        After the second major disaster I  added  dowels  and  have  used
        rubber bands. Since that change I haven't broken anything.
        
                On the other side I did manage  to  launch  my PT-20 with
        only 4 bands and had the wing shift  and  the  plane  go  into an
        irrecoverable spin.  It's still in the shop as  a  result of that
        crash.
        
                Morale:  Use rubber bands, and enough of them, until  you
        can keep the wings off the ground on impact, sorry landing.
        
        Anker

    
    re .*
    
    Rubber bands should be replaced after TWO flying sessions.  Cheap
    insurance!!
    
    At our club the .40 size trainers and sport planes use eight #64
    rubber bands with success.  
   
   I think that if you follow these guidelines that rubber bands are
   very dependable and reliable.
    
   Good luck
    Tony

    Eaglet's have a problem with the front of the wing lifting. It's
    prob due to the holding dowl being slightly back from the front
    of the wing. Suggested rubber band rules:
    o Never use them more than once.
    o min 10. 14 for 40's and 16 for 60's
    o #64 from your hobby shop
    o always hook to the leading edge first and pull them back to the
      rear dowl.
    I like rubber bands especially on my sticks. They have just the
    right amount of give the plane needs when doing things like full
    throttle snap roles.
    
    bob
    

Last weekend my instructor advised 8 bands on my Eaglet.  I
suspect yours failed because of oil soaking or age.  Thanks for
bringing that one up; I will be more cautious because of it.

P.S.  After 2 years of construction, the Eaglet finally flew.  I
even twiddled the stick for a few seconds, before I messed it up
and had to give it back to the instructor.  Hope to fly it for a
full lesson tomorrow.

    It's a real nice flying plane.  If your radio has dual rates, use
    them.  It makes learning easier.  
    
    Yes, the oil soaking and aging are correct. I had been using the
    same bands for quite a while.  As a matter of fact, one or two of
    them had already started splitting!  My loss your gain!  Glad to
    be of service to you and your plane.  This is where I get my info
    on how to fly, what not to do, and so on.....  Lets keep inputting
    all info guys...especially the MISTAKES we make so others won't!
    
    Ken

I have read this note with a great amount of interest.  I have some 
advice and a very specific tip regarding the topic being discussed in 
this note.

ADVICE:

-  use rubber bands for wing hold down while you are learning to fly

-  if you so desire, once you have learned to fly (and land!) well then 
go to the use of nylon bolts

TIP:

Forget this stuff about "x" rubber bands for a plane with engine size 
"a", "y" rubber bands for engine size "b", etc.  There is a much simpler 
method for determining whether you have a sufficient number of rubber 
bands holding the wing on -- simply test it!!  "How?" you might ask...

After fastening your #64 rubber bands on the wing (and yes, 5 or 6 on 
each side is a reasonable start), from in front of the plane place the 
left hand under the right wing close to the fuselage with the finger 
tips right on the main spar and the thumb hooked up and over the leading 
edge; do the same with the right hand under the left wing.  Now lift the 
plane well clear of the ground, and jerk your hands down sharply for a 
distance of about two or three inches, stopping them suddenly.  The 
idea is to put a quick, sharp stress on the rubber bands.  (And before 
someone worries about this overstressing and breaking the wing, if it 
won't stand up to this it isn't safe enough to fly.)  If this maneuver 
causes the wing to separate from the fuselage at all, ADD MORE RUBBER 
BANDS.  If the fuselage and wing stay firmly joined, one of two things 
is true:

1 - you are using enough rubber bands to hold wing and fuz firmly 
together

2 - you aren't snapping the wing downward hard enough to give it a real 
test, so the results are invalid

Maybe you "trainees" would like another tip.  How many of you find that 
your wire landing gear has a tendency to get a little bent up on those 
rough landings beginners have a tendency to make?  Try this - purchase a 
Hallco (or similar) type formed aluminum landing gear that is of 
appropriate width and strength for your plane.  Remove the wire landing 
gear.  Run two dowels through the fuz where the gear goes on, with the 
distance between the dowels a little less than the width from front to 
back of the formed aluminum landing gear.  Now fasten the new gear on 
with two #33 rubber bands on each side.  Depending on the size of the 
gear, you usually have to loop each #33 back and forth around the dowels 
3 to 4 times.  You now have a shock absorbing landing gear, and given 
the worst case of an extremely hard landing, all that should happen is 
that the rubber bands break.  Rubber bands are cheaper and easier to 
replace than torn out fuz bottoms.  By the way, the landing gear rubber 
bands need to be checked and replaced just like the wing rubber bands...

Another tip - sawdust is another good agent for storing rubber bands in. 
Like talcum powder, it absorbs the oil, and it has the advantage of 
being cheaper.

Sorry, it seems as though I have gotten a bit carried away and wordy.

This is a great conference, keep it up guys.  Just wish I got to read it 
more often...  Just like I wish I had time to reply to note #4...  And 
time to build more...  And time to fly more...  And time...

Regards,
Ken Parker 

Great tips - I followed your advice on testing my wing bands.  Left hand on
the right wing, right hand on the left wing, etc.  When I jerked my hands down 
sharply I heard this loud pop.  When I turned around there was balsa pieces
all over my TV.  You forgot to say I should be facing the plane :-)

Actually I was about to put an aluminum gear on my Black Baron Special.  The
last crash made straightening the gear a challenge.  But I was going to mount
hardwood and use nylon screws.  Won't the rubber bands tend to rip the dowels
out of the fuz?  The bottom of my Fuz is just balsa sheeting!

              _!_
Bye        ----O----
Kay R. Fisher / \
 
==============================================================

    
    	I'd put some 1/8" ply plates inside the fuselage through which
    the dowels pass.  Helps distribute the load.  If you leave it just
    balsa, make your landings very gentle.

    Recently I had the first flight of my Spirit with rather unhappy
    results....but that is another story. My question concerns wing bolts.
    My landing was rather (to put it mildly).......rough! I proceeced to
    rip out both wingbolt plates out of the fuse. Wing ok, fuse not so
    good. I rebuilt the wingbolt plate/fuse Much stronger than in the
    original kit......Probably as strong as Mr. Ed. I now look at the bolts
    themselves and wonder if I should score them partway aroung so-ist they
    might shear rather than my wing in future not-so-perfect landings. I am
    using (2) 1/4-20 nylon bolts and believe they would probably stop a
    train. I know, I should have used rubber bands until I become more
    proficient, BUT I DIDN'T. So, all you "stress engineers" (or maybe that
    should be refrased as "stressed engineers", please fire your salvos and
    let me know what you think I should do to make a shear bolt. Or should
    I just leave them alone and hope for the best or just don't fly it
    until I get better  :^).  Tanks.

Drill into them with a 1/16" drillbit from the side at the level they come
through the wing. The othe option would be to put in some brass inserts in the
1/4" holes and use a smaller bolt (8-32?)

    Be careful if you are winch launching - if you make the bolts weak
    enough, you will pull the wing off on an agressive launch.  You could
    modify it to use rubber bands until you get to a point that you can
    safely use bolts.
    
    Charlie
    

You may have solved the problem with the beefed up wing bolt boxes. I
had a similar incident while I was test flighting my spirit-100. That
one has four wing bolts and I popped the heads off of the back two bolts
and sheared the front ones. I used 1/4 inch diameter bolts (are those 4-40?)

Didn't even dent the wing. Amazing...

Anyway, I had beefed up the wing bolt boxes when I originally built it,
and the fuse separated a little from the front plate but that was about
the extent of the damage.

Dave

    Be careful Guys, 
    		remember that the wing bolts and supporting hardware like
    shear plates are there providing a weak point to save the model from any 
    major damage. They are supposed to be the weakest point when making 
    contact with the earth. (Exceptions: this I guess realy only holds true 
    for beginner and intermeadiate models. When you get to the higher speed 
    and areobatic modelling then they simply form a removable joint between 
    two components of the model)
    
    As previous notes point out the trick is to make it strong enough for ALL
    flying manouvers including reasonable landings, whilst not making them
    too strong so that something other than the wing/fuz joining breaks. 
    
    Compromises..
    
    The rubber bands provide an ellastic connection which to some extent
    can be simulated buy enclosing the fixing bolt with a rubber tube and
    washer and/or using rubber or foam wing seating tape.
    
    If you can't reduce the bolt strength use some kind of shear plate.
    
    Trev 

    I'd say it's worth trying a #8 nylon bolt in place of the 1/4-20. If
    that proves too strong (only one way to find that out...), then replace
    it with a #6. You can go with rubber bands, but I still managed to beat
    up the fuse and the wing even with rubber bands on my Prophet. The
    problem is I put so many on to hold the wing securely in place that
    when the wing shifted during a bad landing the rubber bands wiped out
    the trailing edge.
    
    Dave