Plane Talk: ESM P‐51B Mustang ARF-2010/08

A popular subject—
all decked out
August 2010 59
Plane Talk: ESM P‐51B Mustang ARF
TOM SULLIVAN
ONLY A FEWaircraft are instantly
recognizable to airplane enthusiasts,
regardless of their age. Among this elite
group is one of the most famous airplanes in
history: the North American P-51 Mustang. It
boasted many revolutionary aerodynamic and
mechanical improvements that combined to
make it one of the best fighters of World War
II.
Many variants of the P-51 were
developed, including the “B.” Not as widely
known or as visible as the “D” model, P-51Bs
began rolling out in May 1943; 1,990 were
eventually made.
My review kit is based on one of those
“B” types, and it is finished in the color
scheme of the “Bald Eagle” that Robert
Eckfeldt of the 374th Fighter Squadron flew.
With a wing spanning 71 inches, this model
comes in at roughly 1/6 scale.
The ESM(Ever Soaring Models) Mustang
from Troy Built Models arrived in one large
box. A smaller box contained the optional
landing gear, which I’ll tell you about in a bit.
When I opened the model box, I found that all
components were well packed and
individually bagged to prevent scuffs,
scratches, and damage during shipping.
The first step in any review is to unpack
everything, take inventory, and lay the parts
out for the kit-contents photo. I also take time
to examine the components and check out the
construction.
Regardless of what piece I would have
The fuel tank included hardware for glow
engines. The supplied tires were hard foam
with gray plastic hubs, and they mounted to
nonretractable wire struts. A two-piece plastic
engine mount was also provided.
Nearly the only thing not included was a
spinner. For that, you’ll need to shop for one
that measures 41/2 inches in diameter and
choose a Vortech P-51-style model from Dave
Brown Products.
Rounding out the kit box was a 16-page
instruction manual. It’s not the best I’ve seen,
but each step is illustrated and the parts needed
are listed for each stage.
The other box housed ESM’s optional
pneumatic retract kit. With the exception of a
retract unit for the tail wheel, it included all the
hardware and plumbing needed to outfit the P-
51 with scale-looking retractable gear.
Both retract units were machined
aluminum and had functioning oleo struts.
High-quality replacement wheels/tires were
also included for the mains and the tail wheel.
The tires were rubber and the hubs were
machined aluminum.
Before I go further, I have one problem to
note: the control hardware (clevises, pushrods,
etc.). When I started the assembly, I found that
several pieces were missing and many other
parts broke or stripped threads way too easily.
I contacted Troy Built about this, and
people there recommended replacing the
problem parts with aftermarket items. After a
couple of quick calls, Du-Bro stepped up and
quickly sent all of the substitute parts I needed.
started with, I couldn’t help but notice the P-
51’s scale paint job, which was applied at the
factory. The paint job was well done and
included all insignia, stripes, markings, etc.
There were no decals to apply. All of that
was done at the factory, and everything was
even coated with a fuelproof, matte protective
finish.
Wing halves, stabilizer halves, and control
surfaces were made from balsa and plywood
and featured typical rib construction with
balsa sheeting. The fuselage, cowl, and
radiator cowl were molded fiberglass, with an
abundance of details molded in (rivets, panel
lines, hatches, etc.). The remaining pieces
(wheel-well covers, drop-tank halves, canopy,
etc.) were vacuum-formed plastic.
Also included was the hardware pack
containing wheels and fuel tank. The control
linkages were a mixture of pull-pull systems
for the elevator and rudder and pushrods for
the aileron, flap, throttle, and tail-wheel
steering. All clevises were the self-tapping
plastic variety.
Trailing a wisp of smoke from scale Keleo exhausts, the P-51B lands best
and consistently with flaps extended, as would any full-scale Mustang.
Photos by the author
60 MODEL AVIATION
I used as much of the original ESM
hardware as possible, so you’ll see a mixture
of brands in the construction photos.
Construction: Because the Mustang is an
ARF, I won’t bore you by regurgitating each
step of assembly. Almost everything went
together in the way that is typical of today’s
ARFs.
The wing halves were epoxied together,
the wing’s servos were attached to hatches on
the underside of the wing, and the stabilizer
halves were epoxied to the fuselage. However,
I encountered a few differences and problems
along the way.
Attaching the wing halves and mounting
the stabilizer halves to the fuselage required a
few holes to be drilled. The kit included
plywood drilling templates for each step; be
sure to use them, because they lined up well
and saved me considerable time.
Subsequent to epoxying the wing halves,
attach the radiator inlet to the wing. This
required a bit of work to get a clean, smooth
fit, because the contours of the fiberglass inlet
didn’t match the wing. Following a bit of
sanding, I was able to align the radiator inlet
with the fuselage, but there were large gaps
between the inlet and the wing surface.
I mixed a batch of five-minute epoxy and
blended in microballoons to help fill those
gaps. Doing work here ensures that air won’t
get into the gaps and pop off the inlet when
the Mustang is in the air.
One of the stranger things I encountered
was where the manual called for the fuel tank
to be installed. It is typically mounted directly
behind the firewall, with the supply and vent
tubes protruding through the firewall, into the
engine compartment.
The manual instructed that the fuel tank be
mounted back near the model’s CG—
specifically, mounted to the same tray where
the servos were mounted. I guess this would
be fine if you were using a gasoline engine,
but it wasn’t with a glow engine.
Another problem was that if I mounted the
tank as instructed, there would literally be
nowhere to put the air tank in the fuselage.
The area normally occupied by the tank would
be inaccessible because the tank would be
blocking it.
I decided that the only thing to do was
mount the fuel tank where it should have
been. This required cutting away part of the
formers to allow the tank to pass through. I
also made a small “T” bracket to attach to that
same former, which would hold the tank in
place.
When mounting the engine, I found that
the firewall had markings from the factory
showing where it thought the engine should
line up. The marks were not even close; they
were off by more than 1/2 inch on the
horizontal and approximately 1/4 inch
vertically.
Instead of using the factory
recommendations, use that old adage:
“Measure Twice, Cut Once.” Or it would be
more accurate to “Measure Thrice, Drill
Once.”
The only other problem I ran into was with
the retractable gear. Specifically, one of the
struts was leaking when under pressure. I
called Troy Built, and someone talked me
through how to fix the gear without sending it
in.
The repair involved removing the air
cylinder from the retract unit. Then I opened
the cylinder and carefully removed the O-ring
that provided the internal seal.
After wrapping a small piece of Teflon
plumber’s tape around the ring’s seat, I
reinstalled it and reassembled everything. The
As an option, ESM sells a pneumatic main-gear retract kit for the
Mustang. It includes metal retracts units, metal oleo struts,
rubber tires with metal hubs, and all required hardware.
It takes roughly 90 minutes to retrofit the
fuselage and install the Keleo muffler
system. Only a couple of small modifications
were required, and instructions were
detailed and easy to follow.
Tubes preinstalled in the fuselage guide
pul l -pul l controls for rudder and
elevator. It’s a nice touch and the
favored system because of its l ight
weight.
For glow models, the fuel tank needs to
be mounted directly behind the firewall
and requires cutting to allow the tank to
pass through. Using scrap plywood, a Tshaped
bracket was made to hold the
tank in place with only two screws.
The review model directly out of the box. Parts’ fit and finish were
top-notch, and all markings were applied at the factory.
Teflon tape gave the O-ring a slightly larger
diameter, making a better seal between it and
the cylinder wall.
The last construction note I have is about
the cowl. Mounting the Saito 1.25 inverted
meant that I had to trim the cowl so that the
rocker-arm covers could protrude from the
underside of it.
While I was at it, I opened the duct under
the spinner to as large as possible, to allow as
much cooling air into the cowl as possible. To
permit the air to escape, I enlarged the rockerarm
clearance cuts so that they extended back
to 3/4 inch from the firewall. I was unsure if
that would be enough for adequate cooling
but thought it was a good place to start.
There are a few finishing touches you can
add to the P-51, to give it that “full-scale”
look, and one of those is the wing drop tanks
that are included in the kit. Each tank consists
of two vacuum-formed plastic pieces that
need to be trimmed and mated. I didn’t intend
to use either of them, but I did assemble one.
It went together nicely with a little care.
The other finishing touches were a pilot
figure and a spinner (neither of which were
included in the kit). I found the pilot figure at
the local hobby store. The aluminum spinner
is a 41/2-inch Vortech from Dave Brown
Products. I ordered mine in the P-51 shape
(naturally) and had it specially cut for my 16
x 8 Master Airscrew propeller.
The spinner was perfect in every way
except for the color. I did some research on
the original “Bald Eagle” and learned that the
spinner should be the same yellow as is on
the front of the cowl. So I lightly sanded the
spinner, coated it with a light coat of Rust-
Oleum spray primer for metal, and sprayed
on a couple coats of Rust-Oleum yellow
paint.
After a light finish-sanding, I coated the
spinner with three coats of Rust-Oleum spray
matte clear. I’m happy to report that the
spinner looks great and holds up to the use of
a starter without flaking off!
All finished, this P-51B came to 13.5
pounds. Comparing that to the 11.5 pounds
cited in the instruction manual, I wasn’t sure
how I could have shaved off 2 pounds. There
wasn’t that much I had added.
Looking at the Troy Built Models Web
site, I found that 11.5 pounds is the lightest
possible weight the Mustang could be, with
no retracts or other options. Since the CG was
exactly where the manual indicated, I decided
to leave it as-is.
Flying: For a warbird kit to capture my heart,
it needs to do a few things at the flying field.
First, it needs good ground handling. By that I
mean it has to taxi well under high speeds and
stay on the mains until I give the input to take
off.
Second, it has to look like it “grooves” in
the air—be smooth and stable. Third, it has to
be controllable on final for landing and
maintain control when slowing to a
reasonable descent speed.
I’m happy to report that the Bald Eagle
met two of those requirements on the first
flight. The taxi, even under high speeds, was
controllable with the rudder.
And the model had no tendency to
unrealistically yank off of the ground. The
same held true in the landing approach. By
using flaps, you can use higher power settings
to bring the Mustang in and that extra
propeller thrust over the controls to make sure
there are no surprises.
The fighter didn’t meet my third
requirement (grooving in the air) until the
second flight. During the maiden hop, the
controls were too touchy for a short-coupled
warbird such as the P-51. Upon landing, I
adjusted the programming a bit and added
substantially more exponential, which settled
the Mustang into that smooth, rail-like
performance.
To my surprise, the Saito 1.25 did a
fantastic job of powering the 13.5-pound
warbird through the sky. If you floor it in
level flight, you have more than enough
power for loops, chandelles, wingovers, and
Immelmann turns. Throttling back to half
power gives the model a nice cruising speed
and makes for great low passes to show off at
the field.
One other cool thing was the installation of
the Keleo exhaust system. Seeing the stacks
puffing out wisps of smoke while taxiing
made the scene realistic. In the air, the cool
factor is even greater with the added benefit of
no ugly muffler sticking out of the cowl.
If you use the exhaust system, you will
need to keep cleaner nearby. With the
exhausts in the scale position, venting is
straight down the fuselage. I found myself
needing to wipe down the fuselage and tail
after every flight.
With more than a dozen flights on the
Mustang, I’m happy to report that ESM was
correct; the paint is fuelproof.
If you are interested in warbirds, you should
consider an ESM kit—especially when you
take into account what you get for the price.
Yes, I had to swap out some of the hardware
and do maintenance on the retract system. But
in return I ended up with a nicely detailed and
great-flying warbird.
I definitely suggest adding the optional
retracts. Not only do they add to the scale
appearance, but their ruggedness compared
with the standard wire gear will pay
dividends flight after flight.
I made the right power choice in the
Saito 1.25. This engine, mated with the
Keleo exhaust system, fit easily within the
cowl, keeping the Mustang’s sleek lines
intact. The Saito also produces more than
enough power. MA
Tom Sullivan
[email protected]
Manufacturer/Distributor:
ESM/Troy Built Models
1650 Honore Ave.
Sarasota FL 34232
(941) 342-8685
www.troybuiltmodels.com
Sources:
Saito
(800) 338-4639
www.saitoengines.com
JR
(800) 338-4639
www.jrradios.com
Du-Bro Products
(800) 848-9411
www.dubro.com
Dave Brown Products
(513) 738-1576
www.dbproducts.com
Master Airscrew
Box 250
Rancho Cordova CA 95741
www.masterairscrew.com
August 2010 63

A popular subject—
all decked out
August 2010 59
Plane Talk: ESM P‐51B Mustang ARF
TOM SULLIVAN
ONLY A FEWaircraft are instantly
recognizable to airplane enthusiasts,
regardless of their age. Among this elite
group is one of the most famous airplanes in
history: the North American P-51 Mustang. It
boasted many revolutionary aerodynamic and
mechanical improvements that combined to
make it one of the best fighters of World War
II.
Many variants of the P-51 were
developed, including the “B.” Not as widely
known or as visible as the “D” model, P-51Bs
began rolling out in May 1943; 1,990 were
eventually made.
My review kit is based on one of those
“B” types, and it is finished in the color
scheme of the “Bald Eagle” that Robert
Eckfeldt of the 374th Fighter Squadron flew.
With a wing spanning 71 inches, this model
comes in at roughly 1/6 scale.
The ESM(Ever Soaring Models) Mustang
from Troy Built Models arrived in one large
box. A smaller box contained the optional
landing gear, which I’ll tell you about in a bit.
When I opened the model box, I found that all
components were well packed and
individually bagged to prevent scuffs,
scratches, and damage during shipping.
The first step in any review is to unpack
everything, take inventory, and lay the parts
out for the kit-contents photo. I also take time
to examine the components and check out the
construction.
Regardless of what piece I would have
The fuel tank included hardware for glow
engines. The supplied tires were hard foam
with gray plastic hubs, and they mounted to
nonretractable wire struts. A two-piece plastic
engine mount was also provided.
Nearly the only thing not included was a
spinner. For that, you’ll need to shop for one
that measures 41/2 inches in diameter and
choose a Vortech P-51-style model from Dave
Brown Products.
Rounding out the kit box was a 16-page
instruction manual. It’s not the best I’ve seen,
but each step is illustrated and the parts needed
are listed for each stage.
The other box housed ESM’s optional
pneumatic retract kit. With the exception of a
retract unit for the tail wheel, it included all the
hardware and plumbing needed to outfit the P-
51 with scale-looking retractable gear.
Both retract units were machined
aluminum and had functioning oleo struts.
High-quality replacement wheels/tires were
also included for the mains and the tail wheel.
The tires were rubber and the hubs were
machined aluminum.
Before I go further, I have one problem to
note: the control hardware (clevises, pushrods,
etc.). When I started the assembly, I found that
several pieces were missing and many other
parts broke or stripped threads way too easily.
I contacted Troy Built about this, and
people there recommended replacing the
problem parts with aftermarket items. After a
couple of quick calls, Du-Bro stepped up and
quickly sent all of the substitute parts I needed.
started with, I couldn’t help but notice the P-
51’s scale paint job, which was applied at the
factory. The paint job was well done and
included all insignia, stripes, markings, etc.
There were no decals to apply. All of that
was done at the factory, and everything was
even coated with a fuelproof, matte protective
finish.
Wing halves, stabilizer halves, and control
surfaces were made from balsa and plywood
and featured typical rib construction with
balsa sheeting. The fuselage, cowl, and
radiator cowl were molded fiberglass, with an
abundance of details molded in (rivets, panel
lines, hatches, etc.). The remaining pieces
(wheel-well covers, drop-tank halves, canopy,
etc.) were vacuum-formed plastic.
Also included was the hardware pack
containing wheels and fuel tank. The control
linkages were a mixture of pull-pull systems
for the elevator and rudder and pushrods for
the aileron, flap, throttle, and tail-wheel
steering. All clevises were the self-tapping
plastic variety.
Trailing a wisp of smoke from scale Keleo exhausts, the P-51B lands best
and consistently with flaps extended, as would any full-scale Mustang.
Photos by the author
60 MODEL AVIATION
I used as much of the original ESM
hardware as possible, so you’ll see a mixture
of brands in the construction photos.
Construction: Because the Mustang is an
ARF, I won’t bore you by regurgitating each
step of assembly. Almost everything went
together in the way that is typical of today’s
ARFs.
The wing halves were epoxied together,
the wing’s servos were attached to hatches on
the underside of the wing, and the stabilizer
halves were epoxied to the fuselage. However,
I encountered a few differences and problems
along the way.
Attaching the wing halves and mounting
the stabilizer halves to the fuselage required a
few holes to be drilled. The kit included
plywood drilling templates for each step; be
sure to use them, because they lined up well
and saved me considerable time.
Subsequent to epoxying the wing halves,
attach the radiator inlet to the wing. This
required a bit of work to get a clean, smooth
fit, because the contours of the fiberglass inlet
didn’t match the wing. Following a bit of
sanding, I was able to align the radiator inlet
with the fuselage, but there were large gaps
between the inlet and the wing surface.
I mixed a batch of five-minute epoxy and
blended in microballoons to help fill those
gaps. Doing work here ensures that air won’t
get into the gaps and pop off the inlet when
the Mustang is in the air.
One of the stranger things I encountered
was where the manual called for the fuel tank
to be installed. It is typically mounted directly
behind the firewall, with the supply and vent
tubes protruding through the firewall, into the
engine compartment.
The manual instructed that the fuel tank be
mounted back near the model’s CG—
specifically, mounted to the same tray where
the servos were mounted. I guess this would
be fine if you were using a gasoline engine,
but it wasn’t with a glow engine.
Another problem was that if I mounted the
tank as instructed, there would literally be
nowhere to put the air tank in the fuselage.
The area normally occupied by the tank would
be inaccessible because the tank would be
blocking it.
I decided that the only thing to do was
mount the fuel tank where it should have
been. This required cutting away part of the
formers to allow the tank to pass through. I
also made a small “T” bracket to attach to that
same former, which would hold the tank in
place.
When mounting the engine, I found that
the firewall had markings from the factory
showing where it thought the engine should
line up. The marks were not even close; they
were off by more than 1/2 inch on the
horizontal and approximately 1/4 inch
vertically.
Instead of using the factory
recommendations, use that old adage:
“Measure Twice, Cut Once.” Or it would be
more accurate to “Measure Thrice, Drill
Once.”
The only other problem I ran into was with
the retractable gear. Specifically, one of the
struts was leaking when under pressure. I
called Troy Built, and someone talked me
through how to fix the gear without sending it
in.
The repair involved removing the air
cylinder from the retract unit. Then I opened
the cylinder and carefully removed the O-ring
that provided the internal seal.
After wrapping a small piece of Teflon
plumber’s tape around the ring’s seat, I
reinstalled it and reassembled everything. The
As an option, ESM sells a pneumatic main-gear retract kit for the
Mustang. It includes metal retracts units, metal oleo struts,
rubber tires with metal hubs, and all required hardware.
It takes roughly 90 minutes to retrofit the
fuselage and install the Keleo muffler
system. Only a couple of small modifications
were required, and instructions were
detailed and easy to follow.
Tubes preinstalled in the fuselage guide
pul l -pul l controls for rudder and
elevator. It’s a nice touch and the
favored system because of its l ight
weight.
For glow models, the fuel tank needs to
be mounted directly behind the firewall
and requires cutting to allow the tank to
pass through. Using scrap plywood, a Tshaped
bracket was made to hold the
tank in place with only two screws.
The review model directly out of the box. Parts’ fit and finish were
top-notch, and all markings were applied at the factory.
Teflon tape gave the O-ring a slightly larger
diameter, making a better seal between it and
the cylinder wall.
The last construction note I have is about
the cowl. Mounting the Saito 1.25 inverted
meant that I had to trim the cowl so that the
rocker-arm covers could protrude from the
underside of it.
While I was at it, I opened the duct under
the spinner to as large as possible, to allow as
much cooling air into the cowl as possible. To
permit the air to escape, I enlarged the rockerarm
clearance cuts so that they extended back
to 3/4 inch from the firewall. I was unsure if
that would be enough for adequate cooling
but thought it was a good place to start.
There are a few finishing touches you can
add to the P-51, to give it that “full-scale”
look, and one of those is the wing drop tanks
that are included in the kit. Each tank consists
of two vacuum-formed plastic pieces that
need to be trimmed and mated. I didn’t intend
to use either of them, but I did assemble one.
It went together nicely with a little care.
The other finishing touches were a pilot
figure and a spinner (neither of which were
included in the kit). I found the pilot figure at
the local hobby store. The aluminum spinner
is a 41/2-inch Vortech from Dave Brown
Products. I ordered mine in the P-51 shape
(naturally) and had it specially cut for my 16
x 8 Master Airscrew propeller.
The spinner was perfect in every way
except for the color. I did some research on
the original “Bald Eagle” and learned that the
spinner should be the same yellow as is on
the front of the cowl. So I lightly sanded the
spinner, coated it with a light coat of Rust-
Oleum spray primer for metal, and sprayed
on a couple coats of Rust-Oleum yellow
paint.
After a light finish-sanding, I coated the
spinner with three coats of Rust-Oleum spray
matte clear. I’m happy to report that the
spinner looks great and holds up to the use of
a starter without flaking off!
All finished, this P-51B came to 13.5
pounds. Comparing that to the 11.5 pounds
cited in the instruction manual, I wasn’t sure
how I could have shaved off 2 pounds. There
wasn’t that much I had added.
Looking at the Troy Built Models Web
site, I found that 11.5 pounds is the lightest
possible weight the Mustang could be, with
no retracts or other options. Since the CG was
exactly where the manual indicated, I decided
to leave it as-is.
Flying: For a warbird kit to capture my heart,
it needs to do a few things at the flying field.
First, it needs good ground handling. By that I
mean it has to taxi well under high speeds and
stay on the mains until I give the input to take
off.
Second, it has to look like it “grooves” in
the air—be smooth and stable. Third, it has to
be controllable on final for landing and
maintain control when slowing to a
reasonable descent speed.
I’m happy to report that the Bald Eagle
met two of those requirements on the first
flight. The taxi, even under high speeds, was
controllable with the rudder.
And the model had no tendency to
unrealistically yank off of the ground. The
same held true in the landing approach. By
using flaps, you can use higher power settings
to bring the Mustang in and that extra
propeller thrust over the controls to make sure
there are no surprises.
The fighter didn’t meet my third
requirement (grooving in the air) until the
second flight. During the maiden hop, the
controls were too touchy for a short-coupled
warbird such as the P-51. Upon landing, I
adjusted the programming a bit and added
substantially more exponential, which settled
the Mustang into that smooth, rail-like
performance.
To my surprise, the Saito 1.25 did a
fantastic job of powering the 13.5-pound
warbird through the sky. If you floor it in
level flight, you have more than enough
power for loops, chandelles, wingovers, and
Immelmann turns. Throttling back to half
power gives the model a nice cruising speed
and makes for great low passes to show off at
the field.
One other cool thing was the installation of
the Keleo exhaust system. Seeing the stacks
puffing out wisps of smoke while taxiing
made the scene realistic. In the air, the cool
factor is even greater with the added benefit of
no ugly muffler sticking out of the cowl.
If you use the exhaust system, you will
need to keep cleaner nearby. With the
exhausts in the scale position, venting is
straight down the fuselage. I found myself
needing to wipe down the fuselage and tail
after every flight.
With more than a dozen flights on the
Mustang, I’m happy to report that ESM was
correct; the paint is fuelproof.
If you are interested in warbirds, you should
consider an ESM kit—especially when you
take into account what you get for the price.
Yes, I had to swap out some of the hardware
and do maintenance on the retract system. But
in return I ended up with a nicely detailed and
great-flying warbird.
I definitely suggest adding the optional
retracts. Not only do they add to the scale
appearance, but their ruggedness compared
with the standard wire gear will pay
dividends flight after flight.
I made the right power choice in the
Saito 1.25. This engine, mated with the
Keleo exhaust system, fit easily within the
cowl, keeping the Mustang’s sleek lines
intact. The Saito also produces more than
enough power. MA
Tom Sullivan
[email protected]
Manufacturer/Distributor:
ESM/Troy Built Models
1650 Honore Ave.
Sarasota FL 34232
(941) 342-8685
www.troybuiltmodels.com
Sources:
Saito
(800) 338-4639
www.saitoengines.com
JR
(800) 338-4639
www.jrradios.com
Du-Bro Products
(800) 848-9411
www.dubro.com
Dave Brown Products
(513) 738-1576
www.dbproducts.com
Master Airscrew
Box 250
Rancho Cordova CA 95741
www.masterairscrew.com
August 2010 63