Elan trouble

Thu Jun 30 19:59:34 AKDT 2005

Many thanks for all the good advice from the list members.  I'm encouraged
to keep working at it.

I think I'll try to move the throttle servo and receiver to the compartment
behind the firewall.  I'll have to cut a hatch to get access to mount them
there.  Might try to build another rudder and elevators and monocoat them.

Reluctant to dump the bellcrank, but might if above doesn't make enough
difference.

I'm using the Sullivan tail wheel for 5-12 lb. models.  Is there a lighter
alternative?

Thanks again,

Jerry

-----Original Message-----
From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org] On
Behalf Of David Lockhart
Sent: Thursday, June 30, 2005 5:10 AM
To: discussion at nsrca.org
Subject: Re: Elan trouble

Jerry,

The MK bellcrank was certainly adds 1 oz or more to the tail, perhaps more
depending on what types of clevises and secondary pushrods your are using -
and such high tech tricky devices are not something you will find Dick
Hanson using.  And while glass/paint can be done with minimal weight gain,
it usually does add some weight (call it 1 more oz), and if the paint on the
fuse itself is heavy, that can effectively add 1 oz to the tail.  And the
actual weight of the stabs and rudder can pretty easily vary 1-2 oz,
depending on the builder (heavier wood, amount of epoxy used).  And, an
adjustable stab can add 1 oz.  Tailwheel assemblies could vary by as much as
1 oz.  Might be as much as 7.5 oz between different builders and hardware
choices.  That 7.5 oz equates to substantially more (as noted by others) on
the nose - maybe 15-20 oz.  Dump the bellcrank and take a close look at
linkage hardware and the tailwheel assembly - you might be able to pull 2 oz
off the tail (reducing noseweight by 6-8 oz).

- AND - on the front end - When the Elan was designed, a YS120 AC was
commonly used - that engine weighed in around 34-35 oz if my memory serves
correctly.  The current day YS 120s are, I believe, 1-2 oz lighter.
Unfortunate, but not too hard to see how 12 oz of ballast could be needed on
this plane (or any other).

I would absolutely move the throttle servo forward - bolt it to the bottom
of the tank floor just behind the firewall - this will effectively add 1 oz
to the nose.  You might also be able to move the RX and switch just ahead of
the LE of the wing - maybe effectively 1 more oz on the nose.  Those
changes, coupled with dropping 2 oz on the tail should get you to the point
of needing well under 4 oz (if any) on the nose.  At 9 - 9.25oz, the Elan
will fly extremely well.

Regards,

Dave Lockhart
DaveL322 at comcast.net

----- Original Message -----
From: "Jerry Wilson" <JWilsonJr at houston.rr.com>
To: <discussion at nsrca.org>
Sent: Wednesday, June 29, 2005 9:35 PM
Subject: RE: Elan trouble

> Jim,
>
> I don't know why it is tail heavy.  I was very surprised.  CG is noted on
> the plan. Fuselage is painted as are horizontal stab, elevator, and rudder
> which were also glassed.    Could be my glassing and paint job is heavy
> although I would not have thought so much weight could be attributed to
> this.  Rudder and Elevator servos are over the wing trailing edge as per
> plan.  Battery pack has been moved to the firewall.  Used Central carbon
> fiber push rod for elevator to MK dual bellcrank and MK control horns.
Push
> pull cable on rudder.  Receiver and throttle servo are about at the CG.
>
> Jerry
>
> -----Original Message-----
> From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org]
On
> Behalf Of Jim Ivey
> Sent: Wednesday, June 29, 2005 5:24 AM
> To: discussion at nsrca.org
> Subject: Re: Elan trouble
>
> Jerry
>  Why is it  tail heavy. Maybe you are using the wrong CG point or did you
> put servos in the tail? Is the tail painted. I think figure out why, then
> solve the problem that way instead of adding all that weight.?
>
> Jim Ivey>
> > From: "Jerry Wilson" <JWilsonJr at houston.rr.com>
> > Date: 2005/06/29 Wed AM 07:14:53 EDT
> > To: <discussion at nsrca.org>
> > Subject: Elan trouble
> >
> > I have a dilemma and could use some advice from the group.
> >
> >
> >
> > After over a year of building I have nearly completed my Elan which is
my
> > first attempt to build a fiberglass fuse pattern ship.  It is painted,
> > covered, servos, push rods, and engine (120 four stroke) installed.
> Weighs
> > about 9 lbs.  Looks pretty nice.
> >
> >
> >
> > The trouble is to get it to balance at the CG point on the plan (8" from
> > wing LE) requires 11 oz in the nose.
> >
> >
> >
> > According to Dick Hansen's plan the weight should be 8 - 10 lbs.  So it
is
> > still within the design range, at ~9.75 lbs.  But even if I can figure a
> way
> > to add 11 oz of weight to the nose, I'm afraid the plane will not fly
the
> > pattern well and am having serious doubts completing.  My intentions
were
> to
> > fly one or two more Sportsman contests with it and then move on to
> > Intermediate.  Would appreciate some opinions/advice from the group:
> >
> >
> >
> > Should I try to figure out a way to add 11 oz wt. to the nose securely
and
> > finish the plane?
> >
> >
> >
> > Or abandon the ship and move on to something else?
> >
> >
> >
> > TIA
> >
> > Jerry
> >
> >
> >
>
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