The links below are from Google and are not necessarily endorsed by Art Wallace
Delta Vortex:
I recently
completed the Delta Vortex by Bruce Tharpe. The plane
comes in two forms.
The all balsa
kit which can be ordered from:
Bruce Tharpe Engineering
Information
available at 541-582-1708
Orders
1-800-557-4470
Cost $119.95
There is a webring and a website on the plane at www.deltavortex.com .
The plane is
also available as a ARF from Cermark. You can look at
it a www.cermark.com . It
runs $269.95
and comes in two color schemes.
I built mine
from the kit. It is not as complex as a traditional aircraft as you really only
build a
wing. It took 40 or 50 hours to complete
but I wasn’t working all that hard on it. There is no cost savings building it
yourself. The covering and glue came out to about $100 which makes my time
worth exactly $1/hour. I greatly enjoyed putting it together and my kids got a
good look at what is inside a plane so I have no regrets building it. If I
destroy it rapidly, the next version will be the ARF. If it survives a while, I
will build another from the kit.
What
will I do next? I could see adding
retracts, a dual axis gyro, and a separate elevator. The plans allow you to
make it with elevons or ailerons and elevator. Since I have flown a lot of flying wings (Zagis and the Delta
Bravo, I built it with elevons. I can see putting in both on the next version.
I modified the
kit a bit. I don’t like slime on my
planes so I mounted the engine with the cylinder horizontal. Putting servos in the feul
compartment did not make sense. Furthermore, putting a 12 ounce feul tank in a plane with a 0.91 engine was not on my
agenda. I moved the throttle and rudder servos to the radio compartment and put
a 32 ounce tank in the feul compartment. The plane balanced with 5 ounces shoved into
the furthest aft area from the radio compartment. Lateral balance was good
without any weight.
I have an O.S.
91 FX engine and a Futaba 8 UAFs 8 channel radio in
it. The computer radio is very
nice because
there is some programming to make it work well.
The plane uses 6 servos.
One for each elevon, one for each of the two rudders, one for steering,
one for throttle.
You can build
it with separate ailerons and elevator and then it would require 7 servos.
Programming it
took a bit of time. I used the Futaba 8U
Computer Radio Super book and the
Getting the Most Out of Futaba’s 8-Channel Radio Control Systems by Don Edberg.
The Don Edberg book was a tremendous help in explaining what mixing was all
about and actually making it work. The basic idea is this.
Channel 1: Left
elevon.
Channel 2:
Right elevon
Channel 3:
Throttle ( I have the throttle cut set as well and it is great)
Channel 4:
Right Rudder
Channel 5:
Channel 6: Left
Rudder (Also Known As FLAP)
Channel 7: Nose
Wheel Steering
PMIX-1: Rudder
to Flap + 100% +100% Link On Trim On Offset 0% SW-A Null
PMIX-2: Rudder
to Channel 7 +100% + 100% Link On Trim
On Offset 0% SW-C Null
PMIX-3: Gear to
Channel 7 +75% +75% Link Off Offset 0% SW-C Down
PMIX-4: Gear to
Rudder -93% -75% Offset 0% SW-C Down
Airbrake Manu
SW-C
With this set
up the airbrake switch causes the rudders to shift in slowing the plane. If you
put the gear up, then the rudders shift out as airbrakes. I will find out how different these effects
are at altitude.
Flying the
Delta Vortex:
Well, I have
now put more than 100 flights on the Delta Vortex and it is a fantastic
plane. I had a number of problems at
first linked to the O.S. 91 engine.
After I replaced the needle valve, needle valve assembly, and needle
valve O rings, I corrected the air leak that was causing problems. The next problem was a loose screw in the
head. The screw fell out, the cylinder started to leak, there was a lot of
vibration and loss of power mid flight.
It wrecked the head gasket. Once that was fixed every thing was
better. The one thing I will say about
the engine problems is simply that I had at least 10 dead stick landings from
engine problems. I was able to put it on the runway every time without any
damage: Fantastic plane.
Once, I got the
engine adjusted, the weather turned lousy. Lousy weather in the Bay Area of San
Francisco is very geographical. I live
in
So, now that I
have more than 100 flights on the plane, most in high wind, I have some
opinions. The plane handles wind well.
It can do most acrobatic maneuvers. I have been practicing the Sportsman
2002-2004 pattern maneuvers with it. It
flies them beautifully.
Takeoffs: Very easy. The large rudders make cross wind
taxing in high wind a bit tough but it can be done. Cross wind take offs are
not a big deal but dip the up wind wing tip a bit to keep it from being flipped
over. Once you are in the air the plane
flies perfectly. Spins are a bit flat.
Hammer heads need a bit of power to keep air going across the rudders.
Everything else is perfect. Inverted flight is easy with a touch of down
elevator. Landings are lots of fun. Line it up, keep the throttle on in the wind,
cut it when you are over the field. The plane has a tendency to make a flat
stall when you loose airspeed. This problem can be a bit weird at first. The
plane will be air born on landing. You will be about 3 or 4 feet from the
ground and the wind must suddenly be less as you approach touch down. The plane
will just pancake in. It looks bad but
the plane survives fine. I cracked my
muffler a month ago (I have it mounted underneath with a side mounted engine)
but have done no other damage.
I have the
airbrakes set up but they make the plane balloon when applied. I think a bit of
down elevator mixed in will help it.
Taxing on the
ground in high wind is a pain. It is
hard to turn it around but it can be done. It then gets going a bit fast
downwind on the ground, brakes might be nice.
I have flown it in winds that were high enough that my car doors had to
be held open to get the plane in. I have also flown it in wind where it was
lifted off the ground and flipped over in the pits. The Delta Vortex is a wonderful plane that
flies exceptionally, makes me look like a better pilot than I am, and can
tolerate lousy weather and lousy landings. It is fantastic.
Impression:
Excellent plane
which flies wonderfully.
awallace@cardiacengineering.com
The links below are from Google and are not necessarily endorsed by Art Wallace