From: howie@intermec.com (Howard Kaplan x1696)
Newsgroups: rec.models.rc
Subject: Building the Goldberg Ultimate Biplane
Date: 13 Apr 92 16:52:44 GMT
Reply-To: howie@intermec.com ()
Organization: Intermec Corporation, Everett, Wa.

Here are my impressions about the Goldberg Ultimate Biplane 
kit:

Configuration:

Power - OS 1.20 Surpass II pumper  with Graupner 15x8 propeller.
Radio JR347 with 5 servos - ailerons (2), elevator , rudder  
     - Futaba 9201 dual ball bearing; throttle Futaba S148.
Tank - Sullivan 16 oz.

I should point out my first love is helicopters, but this plane really
grabbed me and I just had to build one!


The kit is pretty complete though there are some components I did not like
and elected to change.  All mounting hardware is included and there were no
missing parts. The balsa was excellent and the ply was pretty good. The
turtle deck on my kit was very nice though I have heard the quality varies a
lot from kit to kit.   The canopy I received had marks all over it that would
not come out.  A call to Goldberg was all that was needed and they sent out a
replacement which was fine.  Following is what I changed:

Tail Wheel - The assembly included (no wheel) puts the load on the rudder
hinges which I did not like so I used a Klett tail wheel assembly.  It mounts
to the fuselage bottom and is coupled to the rudder with springs. The throw
is about half that of the rudder and makes ground handling very nice. The
unit comes with wheel.

Hinges - I have never like Goldberg hinges. They are very stiff. I used Sig
E-Z hinges throughout.

Cowl - The three piece cowl is tedious to build, and it is difficult to get
the seams invisible.  After assembling the cowl I decided to change it and go
with a fiberglass cowl from Fiber Glass Specialties.  One advantage of the
after market cowl is they do not have the area formed where the gear comes
out so you can move the cowl back and forward to adjust clearance to the
spinner. If you use the Goldberg assembly you will have to be very precise on
your engine mounting or you could cut off the formed area by the gear exit
point.

Landing Gear - The wire gear is adequate, but a hard landing will cause it to
bend. (This information was passed to me from other builders of the Ultimate
in my area.) I replaced it with an aluminum (.160" T6) from Fiber Glass
Specialties.  Expensive but very nice.  The gear eliminates the need to build
the gear skirts included with the kit.

Engine Mount - The mount included is only good for a .60 size engine which I
do not recommend for this plane. I am not sure why Goldberg advertises this
plane as a .60 size and I can't imagine flying it with a 0.60. size engine.
I used a J'tec soft mount specifically designed for the OS 1.20.

Stringers - I replaced the balsa stringers with basswood.

Now on to the building. There are areas I would change if building another
Ultimate and I mention these as I go along.  The manual is very good and the
plans are also very good. I don't believe there were any errors, though some
of the steps were a little vague.  The other thing missing is the sequence of
covering, radio installation etc..  I have tried to put things in the order I
built the kit.  There really are no instructions on radio installation nor
control rod assembly short of a brief mention of installing aileron servos
out in the bottom wing.  The plans do show where the servos should be
positioned and the configuration of all control rods.

First steps include building up the horizontal stab, elevators (independent)
vertical stab and rudder.  These are all simple with the exception of shaping
control mating surfaces and the rounding of leading edges. The rounding tool
I could never get to work and there were no instructions on its use. I just
used a sanding block to round the leading edges of the horizontal stab and
vertical stab. The vertical stab has an area where a fillet joins to the
turtle deck, so don't round the leading edge in that area until after the
fillet is glued in.   I also did not round or taper the trailing edges of the
rudder or elevators. I have received some comments on how this should have
been done, but the plans did not call this out.  The horizontal stab and
elevator hinge surface need to beveled. The kit comes with a tool, but I
recommend buying a specialized sanding tool for this purpose.  I also skipped
the steps for drilling hinge holes since I used Sig E-Z hinges. Slotting with
and Exacto knife is all that is needed to mount the hinges. Be sure and get
the slots centered properly.

Assembly now turns to the wings. The job is pretty straightforward, but be
sure and build on a flat surface. My wings turned out a little off. Both
wings had about 1/4 inch dihedral (bottom tips up and top tips down) and one
wing had a little washout. With a biplane it is hard to correct this type of
problem, because the two wings are pushing against each other and adjustments
on one wing effect the other.  Bottom line is don't hurry here, build them
straight on a good flat surface and you will avoid the hassles of correcting
the problem later.  If you are going to use wing mounted aileron servos you
will have to make your own servo mounts.  Go through the wing steps a few
times and eliminate any steps for installation of the single aileron servo
control rods.  The manual shows a method that would not allow easy servo
removal. I changed it slightly and essentially built up ply servo trays that
are screwed into blocks glued into the wing. The servos trays can be removed
from underneath the wing.  The Futaba 9201 servos were mounted horizontally
and they just fit in the wing.  Now bevel the ailerons and again I recommend
a sanding tool for this rather the built up jig.  Slot for hinges and
temporarily mount the bottom wing ailerons.  Locate the aileron horns and
temporarily pin or tape them in place.  Build up the aileron links. You will
have to connect the aileron servos to your receiver and turn the gear on to
get the servo horns located properly.  You want the control rod attachment
point to be perpendicular (at center trim) to a line through the center of
the servo to minimize differential throw. I used heli ball links and a round
servo wheel.  You will need to extend the aileron wires to the center area of
the wing. I just cut them and spliced in the additional length. You could use
aileron extension, but I do not trust hidden non-accessible connectors.
Route the wires through the ribs to the center sheeted section and cut two
access holes for the connectors.  You can now cover the wings if you want.

Next in line is the fuselage. You will need to have your engine and mount
before starting this section.  With the OS 1.20 pumper I had to move the
firewall back almost 1 inch so the gap between spinner and cowl would be
proper (1/8 inch).  Spend a lot time planning the engine firewall
installation.  The engine should be screwed to the mount and have the spinner
installed.  Lay it over the top view plan and line up the rear of the spinner
1/8 inch in front of the cowl surface.  Transfer the rear mount surface
location to the plan. Be sure and include the proper space for the soft mount
grommets! This will locate the front surface of the firewall.  Transfer this
location to the side view and then to the plywood side pieces.  Cut the new
slots for the fuselage sides.  The plans call for 2  degrees of right thrust
(I was told to use 3 and did with the OS1.20.) I put the thrust in by a shim
under the front engine mounts screws rather than on the left engine mount
bracket at the firewall.  With the soft mount it seemed easier to do this
way.  The center line of the prop surface should come out on the center line
of the fuse. Because of this the center line of the engine will be to the
left of the center line of the fuse at the firewall.  You will have to work
out the exact mounting hole locations with this in mind.  The marks on the
firewall are not correct for the bigger engine.  Beyond this point the fuse
goes together pretty close to instructions. The only other change needed was
to move former BB back to accommodate the fuel tank. This was necessary
because the firewall and hence the tank moved back and also because I used a
16 oz. rather than 14 oz. tank.  The other complication with this occurred
when installing the top balsa sheeting. The fuse is tapered front to back and
former BB needs to be sanded to get the taper correct since it was moved back
roughly 1.5 inches.  If you don't do this the sheeting will split.  Two more
minor changes.  The metal cabanes should be mounted with larger washers under
the screw head to prevent them from pulling through the ply.  Last as I
mentioned above the front stringers were replaced with hardwood.  The turtle
deck and sheeting are a little tricky installing. Be patient and wet them
down good for forming and you should have no problem.

At this point I departed from plan and built up the elevator control rods.
Temporarily installed the elevators and rudder and started work on the servo
installation.  My reason for this is it would be pretty difficult to get the
elevator rods in once the fuse was covered and the same goes for the rudder
pull-pull cables.  I also installed the engine to locate throttle servos and
linkage.  I left the rudder cables and elevator rods taped just inside their
exit slots. Once covered it was and easy matter to slit the covering an pull
them out.

The cowl needs a cutout for the engine. Start slowly and gradually enlarge
using a Dremel to give around 1/4 inch clearance all around. The rear
clearance will have to be bigger to facilitate getting it on.  I used blind
nuts and screws for mounting.  Don't forget to cut out the cooling inlets and
needle adjust access holes.

Next is building the interplane struts.  Goes per plan except unless you add
some brass tubes through the mounting holes the balsa area around the screws
will crush. Hardwood blocks are an alternative.

I now went to covering the wings and struts.  On the top wing be sure and
locate the wing mount pin hole while covering. I had a hard time locating the
hole after the fact!  The plans now turn to the wing alignment and mounting.
I went with the kit mounting method, but some good changes could be made
here.  On the bottom wing cut out the balsa sheeting in the area were the
screws will seat. Build these up with hardwood shims. The balsa will crush
otherwise (as mine did) and it just looks bad even though it cause no
problem.  The top wing mount is the thing I hate the most about the kit. The
pin works well, but getting it in the rear hole in the mount is tedious and
frustrating. I recommend this method be abandoned totally and install
hardwood wing mount blocks with screws and nuts.  The nuts could be hidden in
the blocks and screws could come up from the bottom of the top wing.   Pay
close attention to the leading and trailing edge height from the fuse top.
This sets the wing incidence and it is critical.

Landing gear and pants. - As I mentioned earlier I did not use the gear
included with the kit. The wheels pants are fine, but have a seam that needs
filling with Model Magic. If you want first class get the fiber glass ones.
Wheels do not come with the kit.

Painting - The cowl, wheel pants, canopy, and cabanes all need painting.   I
chose the scale blue and yellow colors.  Unfortunately there are no spray can
paints that match the Goldberg UltraKote blue.  Mixed up automotive lacquer
is the best bet and I got it matched pretty close. This type of paint is not
fuel proof and needs to be clear coated with fuel proof paint.  The cabanes
should be pre-painted prior to installing on the fuselage.  The canopy is
made out of a material that does not take paint well.  It needs to be fine
wet sanded in the area to be painted. I painted mine on the inside and went
with black to avoid matching to the UltraKote blue.  I installed the canopy
with double sticky tape strips to avoid glue attacking and lifting the
paint.

Covering - I used Goldberg UltraKote blue and yellow for the scale look.  The
yellow requires a double coat to prevent the bleed thorugh of the blue.
(Putting yellow down first and going over with blue is an alternative, but
requires much more material and adds weight.  Another alternative is to
prejoin the yellow trim to the blue, but this is tricky to do properly and
get the joints straight.) It turned out real nice, but the painting matching
was a hassle. The Goldberg blue spinner did not match the UltraKote nor my
mixed up cowl paint so I opted for a balck spinner. I also painted the
aluminum gear black.  I recommend going with a basic white plane with accent
color trim. This will make matching the cowl and pants a lot easier and will
eliminate the need for special paints.  I am used to using MonoKote and
prefer it over UltraKote, but the MonoKote blue does not match the blue of
the kit decals.

I now installed all moveable surfaces permanently and all control horns and
control rods.  Radio gear was installed and surface throws adjusted per
manual.

At this point I turned to checking the wing incidence and alignment. I highly
recommend you borrow or buy a meter.  Unfortunately I discovered I had a
problem with washout in the upper right wing and as I mentioned early on the
wings had a little dihedral towards each other.  The dihedral probably
wouldn't hurt, but I wanted to have the wings per plan of zero incidence and
no dihedral and no wash out. I was able to achieve this by shimming the
interplane struts and when I got the correct amount of correction built them
up and re-drilled the mounting holes.  The extra time getting the wings true
paid off since the plane trimmed out perfectly and flies straight and level
upright or inverted.

Bottom line is this is not an easy kit to build and takes a large amount of
time.  I bought it mid-November and it was in the air on 3/30.  I would
estimate it took around 300 hours build time.   It is well worth the effort
since it flies great and looks super!

Howard Kaplan