Dennis Weatherly
Jan 01, 1997, 01:00 AM
<html>
<head>
<title>The BGM Electroscreamer</title>
</head>
<body bgcolor="#FFFFFF">
<p align="center"><img src="http://static.rcgroups.com/articles/ezonemag/1997/../images/Esfront_1.jpg" width="515" height="282"> </p>
<h2>Introduction </h2>
<p>Are you looking for something a little bit different for your next project? Maybe
you're thinking about trying a ducted fan model but you're not too sure about the
complexities of electric jets? Well, here is a neat little model that will ease you into
jet flight and turn a few heads at the local flying field. </p>
<p>The Electroscreamer is a pocket-sized ducted fan model designed by Don Belfort. It was
designed to utilize the inexpensive Hi-Line Red Flame Blaster ducted fan unit. Don's plane
was originally published by Roger Jaffe in the January 1995 issue of Model Builder
magazine. That version used a completely built up structure, with sticks to frame the
fuselage and tail feathers. </p>
<p>Don has now teamed up with Bill Griggs Models to kit the Electroscreamer. Along the way
the built up fuselage and tail were replaced with lightweight sheet balsa to make
construction easier. The plans have also been loaded into a CAD program for more accurate
reproduction. </p>
<h2>The Kit </h2>
<p>Inside the narrow brown kit box you'll find a minimum of stuff. Pre-cut fuselage sides,
stab, elevator and fins lay beside the nicely drawn CAD plans and a bundle of balsa and
spruce sticks. Wing ribs are also precut and are packaged in a large zip-lock plastic bag
along with various other balsa bits and hardware. All of the balsa in the kit was
excellent quality; I'm notorious for replacing wood in kits but I used every last stick in
this one. Also included was a clear, six page step-by-step construction manual. </p>
<h2>Construction </h2>
<p><img src="http://static.rcgroups.com/articles/ezonemag/1997/../images/esqtrbnz.jpg" align="left" hspace="0" width="474" height="325">The
instructions start with the wing. This is a pretty simple structure since there is no
leading or trailing edge sheeting. The lower spar is spruce, the top spar is balsa and
pre-cut balsa shear webs tie them together for plenty of strength. In this kit I found all
of the shear webs to be 1/16" too long, which slowed down progress a bit as each one
was trimmed to length. I also ran into some minor problems with a couple of the wing ribs;
the top spar notch on rib 5 was 1/16" off, as was the bottom spar notch in rib 6.
Ribs 4, 5 and 8 were a bit too long as well. Nothing major, but a little checking and
fitting was required along the way. </p>
<p>I puzzled over the 1/4" trailing edge, as I couldn't find it or the 3/4"
aileron stock anywhere in the bundle of sticks. A careful review of the plans cleared up
the confusion. There is a piece of 1" trailing edge stock which is used to build the
wing, then the ailerons are sliced off after sanding. Neat, simple and a good way to
ensure the ailerons will match the trailing edge! The instructions call for the builder to
assemble some strip aileron linkage from brass tube and music wire. I found that Sig makes
a very nice 1/2A size aileron torque rod set that works just great and gives you
adjustable length aileron horns. </p>
<p><img src="http://static.rcgroups.com/articles/ezonemag/1997/../images/estopbnz.jpg" align="left" hspace="0" width="490" height="319">
The fuselage came next. When I compared the sides to the plans I noticed two things: the
wing saddle cutout appeared a little bit short and the sides seemed to be 1/16" off
along the top and bottom, from the wing trailing edge on back. I kept everything lined up
and proceeded with construction. The 1/16" sheet sides are joined using two formers
that are constructed from 1/8" square sticks. These had to be notched a bit to clear
the wing saddle doublers. Once joined, the sides are pulled together with 1/8" square
spacers along the top and bottom. The fuselage top is sheeted from the wing leading edge
forward. The bottom is sheeted from the wing trailing edge forward. A balsa block forms
the nose. </p>
<p>Now the secret of the missing 1/16" on the sides was revealed. Rather than
sheeting the tail of the fuselage, Bill Griggs uses a 1/16" by 1/4" strip along
the edge of the fuselage, top and bottom. This stiffens the sides enough, acts like a
gusset at each 1/8" square cross member and saves a bit of weight. Neat! The tail
feathers are simple sheet balsa and are already cut to shape. Since the Electroscreamer
has twin fins I decided to check that the stab tips were square. It was a good thing that
I checked, as I found both tips were off enough to possibly hurt the flight performance. A
few quick slices with a knife along a drafting triangle and all was fixed. </p>
<h2>Covering </h2>
<p>I elected to use Super Monokote to cover my model. The fuselage and tail could probably
accept any covering, but the lightweight wing gained a lot of torsional stiffness from the
Monokote. Think ahead when you cover this model. I always like to completely assemble my
planes before I cover them. On the Electroscreamer this means that you have to deal with
the thin fins out there on the ends of the thin stab, with the fuselage hanging from the
whole shebang. It can be done, but I would recommend that you cover the fins _before_ you
glue them onto the stabilizer. </p>
<h2>Hardware </h2>
<p>The Electroscreamer was originally designed for the Hi-Line Red Flame Blaster ducted
fan unit. This is a nicely made, inexpensive unit that includes a small six to seven cell
motor. The fan shroud and impeller are molded of gray plastic. The spinner and motor
fairing are molded of thin white foam. Another option for power would be the ElectroJet
Speed 400 fan, using either a Speed 400 class motor or an AP29. The new RoJet fan from
Robbe might also work, although the 12 cell motor for that fan might lead to excessive
weight. </p>
<p>Don't let the diminutive size of the Red Flame Blaster fool you. I casually fired mine
up for the first time with the model sitting on my workbench. It only took a couple of
seconds to blow my T-pins, CyA, Uber Skiver knife and the instruction book off the bench!
Treat these little jets with some respect. I powered my model with the Red Flame Blaster
on a seven cell pack of Sanyo 500AR's. Motor control is provided by a Simprop RS400 with
BEC. The radio is a mixture of an RCD 535 receiver, one DAD Tina servo on ailerons and a
Futaba S133 on elevator. The instructions make no mention of control throws, so I set the
elevator at +/- 1/4" and the ailerons at +/- 3/16" inch. The balance point works
out to be right on the wing spar. </p>
<p align="center"><img src="http://static.rcgroups.com/articles/ezonemag/1997/../images/estop.jpg" width="452" height="294"> </p>
<h2>Flight Performance </h2>
<p>Due to the unusually wet weather here in Oregon I haven't flown the little jet too
much. The little jet sat on the bench for almost a week before there was a break in the
rain. Since there were no noise suppression capacitors in the Red Flame Blaster I did a
careful range check, with the power set at various levels. Everything was fine, so I
topped off the battery and launched. The Electroscreamer is a snap to hand launch. A
gentle push straight ahead is all that was required. It climbs quite well and controls are
very positive. The elevator throw proved just fine, but the roll rate was a bit sluggish.
I'll increase the throw a bit and gap seal the surfaces. </p>
<p>Rolls, or in my case Slow Rolls, are nicely axial. Loops can be performed from level
flight, but the little jet runs out of steam near the top if the loop gets too big.
Inverted flight was fine and required a bit of down elevator. Be sure to carry some power
on the landing approach. Remember that jets don't have the prop blast over the controls,
so you need to maintain some airspeed as you fly the pattern. Also, that fan unit sticking
up in the breeze makes a great air brake when you shut the motor off. Just fly it down to
the runway, then chop the power and flair. The Electroscreamer will slow down nicely,
however the sink rate can get a bit high once the power is cut. </p>
<p>Overall, if you can handle an aileron-equipped sport model then you can fly this jet.
It is slower than a Speed 400 pylon racer and much easier to launch and land. </p>
<h2>Wrap Up </h2>
<p>Despite a few niggling problems with some part fits I was very pleased with this
project. The plans are clear, the wood is great and the plane is a ball to fly. If you
have the urge to try your hand at being a "jet jockey" then the Electroscreamer
would be a great and inexpensive first ducted fan. </p>
<h2>Specifications </h2>
<ul>
<li>wingspan: 32.5 inches </li>
<li>wing area: 201 square inches </li>
<li>length: 24.5 inches </li>
<li>weight: 17 ounces </li>
</ul>
<h2>Suppliers </h2>
<address>
Bill Griggs Models <br>
RR2 Box 64 Whitelaw Rd <br>
Canastota, NY 13032 <br>
USA <br>
315-697-8152
</address>
<address>
Hi-Line, Ltd <br>
P.O. Box 11558 <br>
Goldsboro, NC 27532 <br>
USA
</address>
</body>
</html>
<head>
<title>The BGM Electroscreamer</title>
</head>
<body bgcolor="#FFFFFF">
<p align="center"><img src="http://static.rcgroups.com/articles/ezonemag/1997/../images/Esfront_1.jpg" width="515" height="282"> </p>
<h2>Introduction </h2>
<p>Are you looking for something a little bit different for your next project? Maybe
you're thinking about trying a ducted fan model but you're not too sure about the
complexities of electric jets? Well, here is a neat little model that will ease you into
jet flight and turn a few heads at the local flying field. </p>
<p>The Electroscreamer is a pocket-sized ducted fan model designed by Don Belfort. It was
designed to utilize the inexpensive Hi-Line Red Flame Blaster ducted fan unit. Don's plane
was originally published by Roger Jaffe in the January 1995 issue of Model Builder
magazine. That version used a completely built up structure, with sticks to frame the
fuselage and tail feathers. </p>
<p>Don has now teamed up with Bill Griggs Models to kit the Electroscreamer. Along the way
the built up fuselage and tail were replaced with lightweight sheet balsa to make
construction easier. The plans have also been loaded into a CAD program for more accurate
reproduction. </p>
<h2>The Kit </h2>
<p>Inside the narrow brown kit box you'll find a minimum of stuff. Pre-cut fuselage sides,
stab, elevator and fins lay beside the nicely drawn CAD plans and a bundle of balsa and
spruce sticks. Wing ribs are also precut and are packaged in a large zip-lock plastic bag
along with various other balsa bits and hardware. All of the balsa in the kit was
excellent quality; I'm notorious for replacing wood in kits but I used every last stick in
this one. Also included was a clear, six page step-by-step construction manual. </p>
<h2>Construction </h2>
<p><img src="http://static.rcgroups.com/articles/ezonemag/1997/../images/esqtrbnz.jpg" align="left" hspace="0" width="474" height="325">The
instructions start with the wing. This is a pretty simple structure since there is no
leading or trailing edge sheeting. The lower spar is spruce, the top spar is balsa and
pre-cut balsa shear webs tie them together for plenty of strength. In this kit I found all
of the shear webs to be 1/16" too long, which slowed down progress a bit as each one
was trimmed to length. I also ran into some minor problems with a couple of the wing ribs;
the top spar notch on rib 5 was 1/16" off, as was the bottom spar notch in rib 6.
Ribs 4, 5 and 8 were a bit too long as well. Nothing major, but a little checking and
fitting was required along the way. </p>
<p>I puzzled over the 1/4" trailing edge, as I couldn't find it or the 3/4"
aileron stock anywhere in the bundle of sticks. A careful review of the plans cleared up
the confusion. There is a piece of 1" trailing edge stock which is used to build the
wing, then the ailerons are sliced off after sanding. Neat, simple and a good way to
ensure the ailerons will match the trailing edge! The instructions call for the builder to
assemble some strip aileron linkage from brass tube and music wire. I found that Sig makes
a very nice 1/2A size aileron torque rod set that works just great and gives you
adjustable length aileron horns. </p>
<p><img src="http://static.rcgroups.com/articles/ezonemag/1997/../images/estopbnz.jpg" align="left" hspace="0" width="490" height="319">
The fuselage came next. When I compared the sides to the plans I noticed two things: the
wing saddle cutout appeared a little bit short and the sides seemed to be 1/16" off
along the top and bottom, from the wing trailing edge on back. I kept everything lined up
and proceeded with construction. The 1/16" sheet sides are joined using two formers
that are constructed from 1/8" square sticks. These had to be notched a bit to clear
the wing saddle doublers. Once joined, the sides are pulled together with 1/8" square
spacers along the top and bottom. The fuselage top is sheeted from the wing leading edge
forward. The bottom is sheeted from the wing trailing edge forward. A balsa block forms
the nose. </p>
<p>Now the secret of the missing 1/16" on the sides was revealed. Rather than
sheeting the tail of the fuselage, Bill Griggs uses a 1/16" by 1/4" strip along
the edge of the fuselage, top and bottom. This stiffens the sides enough, acts like a
gusset at each 1/8" square cross member and saves a bit of weight. Neat! The tail
feathers are simple sheet balsa and are already cut to shape. Since the Electroscreamer
has twin fins I decided to check that the stab tips were square. It was a good thing that
I checked, as I found both tips were off enough to possibly hurt the flight performance. A
few quick slices with a knife along a drafting triangle and all was fixed. </p>
<h2>Covering </h2>
<p>I elected to use Super Monokote to cover my model. The fuselage and tail could probably
accept any covering, but the lightweight wing gained a lot of torsional stiffness from the
Monokote. Think ahead when you cover this model. I always like to completely assemble my
planes before I cover them. On the Electroscreamer this means that you have to deal with
the thin fins out there on the ends of the thin stab, with the fuselage hanging from the
whole shebang. It can be done, but I would recommend that you cover the fins _before_ you
glue them onto the stabilizer. </p>
<h2>Hardware </h2>
<p>The Electroscreamer was originally designed for the Hi-Line Red Flame Blaster ducted
fan unit. This is a nicely made, inexpensive unit that includes a small six to seven cell
motor. The fan shroud and impeller are molded of gray plastic. The spinner and motor
fairing are molded of thin white foam. Another option for power would be the ElectroJet
Speed 400 fan, using either a Speed 400 class motor or an AP29. The new RoJet fan from
Robbe might also work, although the 12 cell motor for that fan might lead to excessive
weight. </p>
<p>Don't let the diminutive size of the Red Flame Blaster fool you. I casually fired mine
up for the first time with the model sitting on my workbench. It only took a couple of
seconds to blow my T-pins, CyA, Uber Skiver knife and the instruction book off the bench!
Treat these little jets with some respect. I powered my model with the Red Flame Blaster
on a seven cell pack of Sanyo 500AR's. Motor control is provided by a Simprop RS400 with
BEC. The radio is a mixture of an RCD 535 receiver, one DAD Tina servo on ailerons and a
Futaba S133 on elevator. The instructions make no mention of control throws, so I set the
elevator at +/- 1/4" and the ailerons at +/- 3/16" inch. The balance point works
out to be right on the wing spar. </p>
<p align="center"><img src="http://static.rcgroups.com/articles/ezonemag/1997/../images/estop.jpg" width="452" height="294"> </p>
<h2>Flight Performance </h2>
<p>Due to the unusually wet weather here in Oregon I haven't flown the little jet too
much. The little jet sat on the bench for almost a week before there was a break in the
rain. Since there were no noise suppression capacitors in the Red Flame Blaster I did a
careful range check, with the power set at various levels. Everything was fine, so I
topped off the battery and launched. The Electroscreamer is a snap to hand launch. A
gentle push straight ahead is all that was required. It climbs quite well and controls are
very positive. The elevator throw proved just fine, but the roll rate was a bit sluggish.
I'll increase the throw a bit and gap seal the surfaces. </p>
<p>Rolls, or in my case Slow Rolls, are nicely axial. Loops can be performed from level
flight, but the little jet runs out of steam near the top if the loop gets too big.
Inverted flight was fine and required a bit of down elevator. Be sure to carry some power
on the landing approach. Remember that jets don't have the prop blast over the controls,
so you need to maintain some airspeed as you fly the pattern. Also, that fan unit sticking
up in the breeze makes a great air brake when you shut the motor off. Just fly it down to
the runway, then chop the power and flair. The Electroscreamer will slow down nicely,
however the sink rate can get a bit high once the power is cut. </p>
<p>Overall, if you can handle an aileron-equipped sport model then you can fly this jet.
It is slower than a Speed 400 pylon racer and much easier to launch and land. </p>
<h2>Wrap Up </h2>
<p>Despite a few niggling problems with some part fits I was very pleased with this
project. The plans are clear, the wood is great and the plane is a ball to fly. If you
have the urge to try your hand at being a "jet jockey" then the Electroscreamer
would be a great and inexpensive first ducted fan. </p>
<h2>Specifications </h2>
<ul>
<li>wingspan: 32.5 inches </li>
<li>wing area: 201 square inches </li>
<li>length: 24.5 inches </li>
<li>weight: 17 ounces </li>
</ul>
<h2>Suppliers </h2>
<address>
Bill Griggs Models <br>
RR2 Box 64 Whitelaw Rd <br>
Canastota, NY 13032 <br>
USA <br>
315-697-8152
</address>
<address>
Hi-Line, Ltd <br>
P.O. Box 11558 <br>
Goldsboro, NC 27532 <br>
USA
</address>
</body>
</html>