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The design team at Airborne were definitely not
experiencing a 'Pipe Dream' when they came up with this one! This model
bi-plane, although a sports model, looks as if it could have been scaled
down from an aerobatic aircraft or home built type.
Its crisp handling qualities, wide speed range and robust structure
makes the Dream Bipe one model you can push through almost any aerobatic
manoeuvres.
A good .46 to .60 size two stroke engine is recommended or a .60 to .90
four stroke will power the model through its aerobatic envelope. I used a
four stroke engine as I couldn't imagine a model of this type with
anything else.
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After unrolling the plans and studying them on the floor in front of
the box for a couple of evenings I started by protecting the plans with
grease proof paper on our building board.
Wings
I always like to start with the wings as it gives me a chance to match
the section to the cut out in the fuselage.
Cut out all the ribs. The sandwich method is an excellent way of
maintaining accuracy.
Only the bottom wing has full span ailerons, the top wing is swept
back.
Start by pinning the spars down making the scarf joints nice and neat,
and using the ribs as a guide, pin a 6mm square under the backs of the
ribs, (just in front of the rear spar housing), so the ribs can be pinned
and held steady.
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Only the bottom wing has full span ailerons which
are built up with ribs and fully sheeted.
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The top wing is swept back and has no dihedral. The
centre section is beefed up with 3mm ply at the strut attachment
points. |
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Form up the wing using ribs making sure that you use the right ribs in
the right places.
Don't forget to install WB4s as these are very important for strength.
Install the top spars and the false leading edge.
I sheeted the front section and turned the whole wing over so as the
wing holding blacks could be installed.
From here it's a simple matter of sheeting the bottom and adding cap
strips. Turn over and finish the top. The LE is attached and can be shaped
using a razor plane.
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At this point you can make the tops or you can leave them until the
bottom wing has taken shape. The bottom wing is much the same but has to
be built in three sections, leaving the centre pinned to the board and
joining the sections in the middle.
Only the bottom wing has a small amount of dihedral. Block up the wing
tips 12.5mm each side and glue the wing joiner brace into place.
Just a short note: Put the strut supports in before sheeting the D-box
sections.
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Complete lower wing showing strut attachment
brackets which must be glued in before sheeting of wing. |
Fin and Tailplane
The large rudder gives good authority for knife-edge
manoeuvres. |
Construction of the tail feathers is simple and straight forward. Use
medium to hard balsa for these components as aerobatic models need to
handle brute forces at times.
Both the fin and the tailplane will take shape very quickly by building
them flat over the plan from 9.5mm sheet.
They are then shaped and slotted for the hinges and await to be fitted
to the fuselage.
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The tailplane and elevator is built flat over the plan. |
Fuselage
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The engine type used will determine the position of the firewall, (F1).
If a four stroke engine is used then move the firewall rearward to suit.
If a two stroke engine is chosen then position F1 where shown on plan.
I opted for a four stroke which meant I had to make allowances for it.
There are two ways of allowing for it with the simplest being to move the
firewall back to suit then extend the engine cowl blocks by the same
proportional amount.
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Prepare the fuselage sides with longerons and
doublers. Cut out formers & Build up the rear ones over the plan. |
The nose and turtle deck is skinned with 3mm balsa. |
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Alternatively you could build a dummy firewall with the actual firewall
boxed 25mm behind the original.
This meant the engine mount and carby protruded through F1 onto the
rear boxed firewall. The motor was inverted to give nice clean lines. Some
of my other planes are set up with inverted four strokes and I have never
had a problem. The other option at this stage is to make the front of the
fuselage with a removable cowl for access.
The fuselage is of typical construction. Start by cutting out the sides
and doublers. I always use contact adhesive for my sides and doublers as I
don't have to wait overnight for drying. The formers can be cut out and
the rear formers, F5, F6 and F7, can be built up over the plan.
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With this done you're ready to box the front section up. Start by
gluing the front formers, F1 to F4, onto the fuselage sides, then pull in
the ends and glue the rear formers, F5 to F7, into place. Glue in the
hardwood cabane strut blocks between F2 and F3, and the turtledeck
stringers.
Put in the undercarriage mount plate and then the bottom sheeting and
decking can be added after the fin and tailplane have been installed.
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Inside the fuselage showing the servo tray, nyrod
for throttle cable and wing location holes. |
The fire wall on my model was set back into the
fuselage. The inverted motor is trouble free. |
The wing struts were made from 1.5mm steel sheet which were cut in the
guillotine for a constant width. This was made as per plan using 3mm bolts
with nylock nuts. They can be made from aluminium strips that are
available from hardware stores.
Just a note on the cabane struts, use a cardboard template to check the
fit before attacking your timber. Pin a piece of scrap between the tips to
keep your wings positioned whilst checking with your template. |
The sleek lines of this model makes it look scale. |
Make the cabane struts, very carefully ensuring they will hold the wing
incidences accurately. Trial fit the wings and check alignment is true
before covering.
Finishing
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The canopy was installed after painting the cockpit out and fitting the
pilot.
The tailplane and fin on my model were covered with Solartex with the
fuselage receiving the dope, talcum and tissue treatment. The fuselage was
finished in gloss enamel and the wings were covered in profilm.
The cabane struts were sprayed with matt black before being fitted to
the fuselage.
Balance the model to the C of G shown on plan.
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Flying
The Dream Bipe is ready to cut through a bit of sky. |
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After a couple of weeks, (seemed forever), the weather was reasonable
with a constant breeze blowing from the west.
The engine was fired up with some adjustments to make sure the engine
was going to be reliable. I pointed the nose down the middle of the strip,
opened the throttle... and away it went.
The model tracked straight down the grass and I pulled back on the
elevator stick.
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We were airborne!!! The model tracked perfectly and I concentrated on
the turn and to gain some height, went around in a circuit. There was no
need to panic, but there is always some apprehension with a new model.
It didn't take long to appreciate that the Dream Bipe's performance
is exhilarating! It goes where you point it.
Loops are tight, rolls are rapid and straight down the line. It spins
like a top with fast recovery, and holds inverted with just a little down
elevator, and flies knife edge well.
The Dream Bipe will perform virtually any aerobatics you like, or are
capable of doing.
Well, after a couple of tanks of fuel this model was right at home and
the landing Ð what a dream! This model exceeds all my expectations and it
lands under power at a very pleasing pace, not fast like a Pitts Special.
So go ahead and build this bipe. You will not be disappointed and there
is only one way to describe it.
What a Dream!
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