130 MODEL AVIATION
E-36 ELECTRIC
FF: Developing an
introductory FF
event is never easy.
The model needs to
be simple and
inexpensive to
attract beginners,
yet the performance level needs to be high enough to excite more
experienced fliers.
Vic Nippert and a few other modelers across the country have
been working to develop an electric equivalent to the popular P-30
Rubber event. The obvious choice of an electric-powered P-30
proved to be a bit small for the weight an electric model needs to
carry.
Increasing the wingspan limit from 30 to 36 inches provides
enough extra area to carry the batteries and motor. A wide range of
motors, propellers, and battery packs used in RC park flyers are
readily available.
The preliminary rules limit span to 36 inches and require a
minimum weight of 150 grams. The motor run is 25 seconds with a
two-minute max. Only brush-type motors are allowed, and the
maximum battery voltage is 4.8. Gears and folding propellers are
allowed.
National Free Flight Society (NFFS) President Rex Hinson’s
Sparks E-36 design utilizes a Powerhouse 36 wing outline with a
rectangular stabilizer. The 180-square-inch wing uses a slightly
undercambered airfoil.
One of Rex’s two models uses a cut-down fuselage from an F1B
Rubber airplane. He shortened the motor tube and carbon-aluminum
boom to fit the smaller model. His other version, shown in the
photo, uses a simple balsa box. Power is a GWS motor with a 4:1
gear ratio driving an 8 x 4 propeller.
John Oldenkamp of San Diego, California, was one of those who
developed the P-30 event in the 1970s. Now he’s working on E-36.
“The emphasis here has been to make stuff that makes sense, is
simple, light, and quick to build,” he said.
John’s eBox 36 features a 6 x 36-inch wing with raked tips,
giving a projected area of 212 square inches. The stabilizer is 4.5 x
14 inches. Both surfaces use a single tubular spar, carbon-rod LE,
Thoughts on the new E-36 electric FF event
[[email protected]]
Free Flight Duration Louis Joyner
Also included in this column:
• A listing of new rubber FF
plans
Rex Hinson’s E-36 design has traditional stick-and-tissue
construction combined with a geared motor driving an 8 x 4
propeller.
Two screws hold battery access panel in place. Line is antenna for
retrieval transmitter. Motor start switch is on fuselage side.
The motor, made for RC park flyers, comes with gears that allow
the high-revving unit to drive a larger propeller. As with Rubber and
Gas models, increasing propeller diameter increases efficiency.
11sig5.QXD 9/26/06 9:21 AM Page 130132 MODEL AVIATION
and carbon-capped 1/16 balsa TE.
The fuselage is a carbon-aluminum tube.
A simple balsa pylon holds the batteries and
other electronics.
“The emphasis here was to reduce the
parts count and glue joints,” said John.
He sets the model up with the CG at 62%
and the wing with 1° of positive incidence.
The motor uses 2° of right thrust and 7° of
downthrust. Power and glide are to the right.
John feels that a rearward CG, often used
with locked-up Gas models, when used with
a slower-climbing electric-powered model
can produce a large stall at motor shut-down.
“My experience indicates something
between 60% and 65% CG gives an almost
Hand-Launched Glider flip at the top, with
smooth glide entry,” he said.
Rubber Model Plans: Colorado Rubber and
Power flier Don DeLoach has developed new
full-size plans for three Rubber designs from
the 1950s. Two are suitable for the Nostalgia
Wakefield event.
The 1955 German design by J. Altmann
features a Benedek wing airfoil and multispar
construction for the wing and stabilizer.
There are five 1/16 x 3/16 spars and one 1/16 x
1/8 spar in the wing. Construction of the
Altmann design is detailed in the May 2006 NFFS Digest. (For
information about the NFFS, visit the Web site at http://free
flight.org.)
An interesting feature of Don’s modern version of the Altmann
Wakefield is his use of small magnets to attach the rather large rudder
to the stabilizer. The removable rudder makes packing much easier.
Doug Moran’s Copacetic I Wakefield utilizes a single-blade
folding propeller and Warren truss fuselage construction; the wing
and twin-finned stabilizer have sheeted LEs. The 1954 vintage
Unlimited Rubber design by Ted Becker has a Gollywock-size wing
but a 31-inch hook-to-hook distance to give a longer motor run. It
also uses a twin-fin arrangement.
The plans are CAD-drawn for accuracy and feature original
information and modern notes. On the Copacetic I Don shows the
original 100% CG Moran used, as well as a suggested 89% CG based
on tail-volume coefficients.
He also suggests using 24-28 strands of 40- to 46-inch-long Super
Sport rubber for an unlubed weigh of 70-90 grams.
John Oldenkamp holds his eBox 36 small electric-powered design (left) and his larger F1Q
electric-powered design. Photo by Bill Burt.
Waiting for covering, the eBox reveals its simple structure. Wing
uses .021-inch-diameter carbon tube spar that provides bending,
torsional stiffness. LE is .080-inch-diameter carbon rod. Fuselage is
.201-inch-diameter carbon/aluminum tube. Burt photo.
It may not snow in Southern California, but it does in Colorado.
Don DeLoach has produced full-sized CAD drawings for the 1955
Altmann Wakefield (shown) and several other Rubber designs.
See text. DeLoach photo.
“Moran’s original motor: 50 inches x 133 grams (gulp),”
wrote Don.
Plans for each of the two Wakefields are $8 post-paid in the
US. Plans for the smaller Becker Unlimited design are $7. Also
available are laser-cut wing and stabilizer ribs for the Altmann
model at $15 per set. (Buying the laser-cut ribs will save you
the time and trouble of making more than 300 spar notches!)
Don also offers plans for his Nats-winning P-30 Polecat 10
design, which was selected as an NFFS Model of the Year for
2006. It features a full-length motor base that gives a long
propeller run. For P-30 the mandatory freewheeling propeller
produces a great deal of extra drag in the glide. A long run
(2,200-2,500 turns!) reduces the amount of time the model
needs to glide to make the two-minute max. Full-size plans for
the P-30 are $7; a set of laser-cut ribs is $8.
To order, send a check to Don DeLoach at 831 E. Willamette,
Colorado Springs CO 80903. You can also E-mail him at ddeloach
@adelphia.net. MA
11sig5.QXD 9/26/06 9:23 AM Page 132
Edition: Model Aviation - 2006/11
Page Numbers: 130,132
Edition: Model Aviation - 2006/11
Page Numbers: 130,132
130 MODEL AVIATION
E-36 ELECTRIC
FF: Developing an
introductory FF
event is never easy.
The model needs to
be simple and
inexpensive to
attract beginners,
yet the performance level needs to be high enough to excite more
experienced fliers.
Vic Nippert and a few other modelers across the country have
been working to develop an electric equivalent to the popular P-30
Rubber event. The obvious choice of an electric-powered P-30
proved to be a bit small for the weight an electric model needs to
carry.
Increasing the wingspan limit from 30 to 36 inches provides
enough extra area to carry the batteries and motor. A wide range of
motors, propellers, and battery packs used in RC park flyers are
readily available.
The preliminary rules limit span to 36 inches and require a
minimum weight of 150 grams. The motor run is 25 seconds with a
two-minute max. Only brush-type motors are allowed, and the
maximum battery voltage is 4.8. Gears and folding propellers are
allowed.
National Free Flight Society (NFFS) President Rex Hinson’s
Sparks E-36 design utilizes a Powerhouse 36 wing outline with a
rectangular stabilizer. The 180-square-inch wing uses a slightly
undercambered airfoil.
One of Rex’s two models uses a cut-down fuselage from an F1B
Rubber airplane. He shortened the motor tube and carbon-aluminum
boom to fit the smaller model. His other version, shown in the
photo, uses a simple balsa box. Power is a GWS motor with a 4:1
gear ratio driving an 8 x 4 propeller.
John Oldenkamp of San Diego, California, was one of those who
developed the P-30 event in the 1970s. Now he’s working on E-36.
“The emphasis here has been to make stuff that makes sense, is
simple, light, and quick to build,” he said.
John’s eBox 36 features a 6 x 36-inch wing with raked tips,
giving a projected area of 212 square inches. The stabilizer is 4.5 x
14 inches. Both surfaces use a single tubular spar, carbon-rod LE,
Thoughts on the new E-36 electric FF event
[[email protected]]
Free Flight Duration Louis Joyner
Also included in this column:
• A listing of new rubber FF
plans
Rex Hinson’s E-36 design has traditional stick-and-tissue
construction combined with a geared motor driving an 8 x 4
propeller.
Two screws hold battery access panel in place. Line is antenna for
retrieval transmitter. Motor start switch is on fuselage side.
The motor, made for RC park flyers, comes with gears that allow
the high-revving unit to drive a larger propeller. As with Rubber and
Gas models, increasing propeller diameter increases efficiency.
11sig5.QXD 9/26/06 9:21 AM Page 130132 MODEL AVIATION
and carbon-capped 1/16 balsa TE.
The fuselage is a carbon-aluminum tube.
A simple balsa pylon holds the batteries and
other electronics.
“The emphasis here was to reduce the
parts count and glue joints,” said John.
He sets the model up with the CG at 62%
and the wing with 1° of positive incidence.
The motor uses 2° of right thrust and 7° of
downthrust. Power and glide are to the right.
John feels that a rearward CG, often used
with locked-up Gas models, when used with
a slower-climbing electric-powered model
can produce a large stall at motor shut-down.
“My experience indicates something
between 60% and 65% CG gives an almost
Hand-Launched Glider flip at the top, with
smooth glide entry,” he said.
Rubber Model Plans: Colorado Rubber and
Power flier Don DeLoach has developed new
full-size plans for three Rubber designs from
the 1950s. Two are suitable for the Nostalgia
Wakefield event.
The 1955 German design by J. Altmann
features a Benedek wing airfoil and multispar
construction for the wing and stabilizer.
There are five 1/16 x 3/16 spars and one 1/16 x
1/8 spar in the wing. Construction of the
Altmann design is detailed in the May 2006 NFFS Digest. (For
information about the NFFS, visit the Web site at http://free
flight.org.)
An interesting feature of Don’s modern version of the Altmann
Wakefield is his use of small magnets to attach the rather large rudder
to the stabilizer. The removable rudder makes packing much easier.
Doug Moran’s Copacetic I Wakefield utilizes a single-blade
folding propeller and Warren truss fuselage construction; the wing
and twin-finned stabilizer have sheeted LEs. The 1954 vintage
Unlimited Rubber design by Ted Becker has a Gollywock-size wing
but a 31-inch hook-to-hook distance to give a longer motor run. It
also uses a twin-fin arrangement.
The plans are CAD-drawn for accuracy and feature original
information and modern notes. On the Copacetic I Don shows the
original 100% CG Moran used, as well as a suggested 89% CG based
on tail-volume coefficients.
He also suggests using 24-28 strands of 40- to 46-inch-long Super
Sport rubber for an unlubed weigh of 70-90 grams.
John Oldenkamp holds his eBox 36 small electric-powered design (left) and his larger F1Q
electric-powered design. Photo by Bill Burt.
Waiting for covering, the eBox reveals its simple structure. Wing
uses .021-inch-diameter carbon tube spar that provides bending,
torsional stiffness. LE is .080-inch-diameter carbon rod. Fuselage is
.201-inch-diameter carbon/aluminum tube. Burt photo.
It may not snow in Southern California, but it does in Colorado.
Don DeLoach has produced full-sized CAD drawings for the 1955
Altmann Wakefield (shown) and several other Rubber designs.
See text. DeLoach photo.
“Moran’s original motor: 50 inches x 133 grams (gulp),”
wrote Don.
Plans for each of the two Wakefields are $8 post-paid in the
US. Plans for the smaller Becker Unlimited design are $7. Also
available are laser-cut wing and stabilizer ribs for the Altmann
model at $15 per set. (Buying the laser-cut ribs will save you
the time and trouble of making more than 300 spar notches!)
Don also offers plans for his Nats-winning P-30 Polecat 10
design, which was selected as an NFFS Model of the Year for
2006. It features a full-length motor base that gives a long
propeller run. For P-30 the mandatory freewheeling propeller
produces a great deal of extra drag in the glide. A long run
(2,200-2,500 turns!) reduces the amount of time the model
needs to glide to make the two-minute max. Full-size plans for
the P-30 are $7; a set of laser-cut ribs is $8.
To order, send a check to Don DeLoach at 831 E. Willamette,
Colorado Springs CO 80903. You can also E-mail him at ddeloach
@adelphia.net. MA
11sig5.QXD 9/26/06 9:23 AM Page 132