Elan trouble

Fri Jul 1 05:09:29 AKDT 2005

Before you make any extensive modifications I suggest you try some temporary 
weight just to assess the problem. I would put the appropriate amount of 
weight in a zip-lock bag, stuff it in the Fuselage as far forward as you can 
get it and secure it with a wad of foam & duct tape. Test fly a few times 
removing a little weight at a time until you find out how much you really 
need. Be certain to not be careless about how you retain the additional 
weight. You would not be the first to lose a plane due to a weight shifting 
to the tail! Lead shot works best but sand/gravel will do. 11 ounces is a 
lot of sand though.

There is a popular notion that a nose heavy airplane is easier to fly. That 
is not altogether true. The scenario goes like: during landing you slow 
down. The stab stalls resulting in a pitch up followed by dropping a wing 
into a cartwheel. The victim frequently rebuilds and adds more nose 
weight....

IF you must add nose weight you can make and aluminum foil mold in the area 
between the nose ring and the spinner, remove it and pour it full of the pre 
measured lead. Easier than it sounds. It goes together easier if you saw the 
lead into a couple of pieces.

Do remove all the weight from tail possible first!

It would be nice to be able to move the wing back a little, but I think that 
a major challenge on an Elan.

John Ferrell
http://DixieNC.US

----- Original Message ----- 
From: "Jerry Wilson" <JWilsonJr at houston.rr.com>
To: <discussion at nsrca.org>
Sent: Thursday, June 30, 2005 11:59 PM
Subject: RE: Elan trouble

> 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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