EPP Foam Combat Plane
Here's what I see as the next generation in 25" foam combat
planes, built with 9mm EPP foam. Starting with a sheet of EPP, I used
the pieces from an unbuilt 25"
BP Fun Foam kit as templates and traced the parts onto the EPP
sheet, using a pencil. Then I cut them out with an exacto knife, using
a metal yardstick for the lines and free-handing the curves.
The LightFlite Easy Bevel can be used to bevel the
control surfaces (make sure the blade is sharp). I like to bevel both
the control surface piece side and the "plane" side, even though it
takes some extra cutting with the exacto knife and a ruler. I put
blenderm on the top and bottom to make the hinges. The control rods
from a BP Fun Foam kit can be used, or duplicates made up (with 0.050"
carbon rods, heat shrink, and 0.030" music wire). For control horns I
used Dubro Micro 2 Control Horns #919, and I used Dubro Mini E/Z Connectors #915 with the stock
servo arms. Holes on the servo arms and E/Z connectors needed to reamed
out a bit. I found that the elevator/rudder pushrods were bowing out,
so I CA'd two rods together, which helps. A pushrod "guide" could also
be used.
I used a 0.098" carbon rod to stiffen the wing, but I think a carbon
strip would be better (less flex and easier to install). A second
(shorter) carbon strip makes the wing stronger. I double-beveled the
leading edge of the wing to a bit of a point, and attached a 0.070"
carbon rod with glue and blenderm tape. I put carbon strips into the
horizontal stabilizer and elevator, and along both sides of the
fuselage. This forces the tail servos to be moved outward, then and
down a bit so the control arms clear the ailerons. There also needs to
be space for the aileron servo, so the strips need to stop before that
servo. The stiffness the strips add to the tail is worth the effort.
I doubled-up on the front part of the horizontal fuse by cutting out
matching foam pieces and attaching them below the existing fuse. See here
for a picture. The back half of those horizontal-fuse pieces could be
made a little wider. I'm referring to the piece under the carbon strip
in this
pic. Making them wider would give the tail more stiffness.
For assembly you can use most any glue you want -- UHU Por, epoxy, CA,
or a combination. I like 5-minute epoxy, so I used it with disposable
paint brushes to build mine. For the carbon strips that go into the
wing and tail, I cut a slot, put in the strip and then apply thin CA
all along it. I use the UHU Por to repair foam tears; some like to do
full builds with it. I used hot glue to install the servos. I'd say
that a plane can be built in 2-3 evenings.
See my gallery of pics of my plane,
taken before painting and after completion. I painted with Testors All
Purpose Spray Enamel (in the small can).
Here is the foam and the carbon strips (larger strips for the wing). A
plane takes up about 3/4 of a sheet:
Qty 1:
9mm EPP Foam (1.9#) - Single Sheet Selection
Selected options:
Sheet Size: 18x36
SKU: 11-405
Price: $ 8.25
http://www.rcfoam.com/cart.php?target=p
... gory_id=83
Qty 2:
Strip 5.0mm x 0.6mm x 1000mm (.197"x .024" x 39") SKU20-109
Price: $ 2.30
http://www.rcfoam.com/cart.php?target=p
... gory_id=96
Qty 2:
Strip 7.0mm x 1.2mm x 1000mm (.276" x .047" x 39") SKU 20-112
http://www.rcfoam.com/cart.php?target=p
... gory_id=96
Price: $ 3.90
The power system can be about the same as for the BP Fun Foam planes:
FC 28-12 Brushless Outrunner 1534kv 16A 39g FC2812 $5.95
http://www.hobbyking.com/hobbyking/stor
... oduct=5423
Hobbyking SS Series 18-20A ESC (card programmable) HK-SS20A-HW $7.80
http://www.hobbyking.com/hobbyking/stor
... oduct=6548
[aileron] HXT900 9g / 1.6kg / .12sec Micro Servo $2.69
http://www.hobbyking.com/hobbyking/stor
... roduct=662
[elev/rud] HXT500 5g / .8kg / 10sec Micro Servo $3.49
http://www.hobbyking.com/hobbyking/stor
... roduct=663
3mm Prop Saver w/ Adapter & 3 bands 3MPRPSVR $1.49
http://www.hobbyking.com/hobbyking/stor
... oduct=3738
Hobby King Battery Monitor 3S HKing-3S $3.99
http://www.hobbyking.com/hobbyking/stor
... oduct=7223
The prop should be the 8x4 because the 7x3.5 doesn't quite have enough
thrust:
GWS EP Propeller (DD-8040 203x102mm) (6pcs/set) $4.05
http://www.hobbyking.com/hobbyking/stor
... duct=10046
Recommended battery is anything from 800mAH to 1300mAh, 3S. Here are
some options:
Turnigy 800mAh 3S 20C Lipo Pack T800.3S.20 $7.09
http://www.hobbyking.com/hobbyking/stor
... oduct=9173
ZIPPY Flightmax 800mAh 3S1P 20C 73g Z8003S20C $8.66
http://www.hobbyking.com/hobbyking/stor
... oduct=6784
Turnigy nano-tech 850mah 3S 25~40C Lipo Pack N850.3S.25 $8.40
http://www.hobbyking.com/hobbyking/stor
... duct=11899
Turnigy nano-tech 1000mah 3S 25~50C Lipo Pack N1000.3S.25 $9.85
http://www.hobbyking.com/hobbyking/stor
... duct=11901
Turnigy 1000mAh 3S 20C Lipo Pack T1000.3S.20 $5.49
http://www.hobbyking.com/hobbyking/stor
... oduct=9163
Turnigy 1300mAh 3S 20C Lipo Pack T1300.3S.20 $8.95
http://www.hobbyking.com/hobbyking/stor
... oduct=9272
Turnigy nano-tech 1300mah 3S 25~50C Lipo Pack N1300.3S.25 $11.30
http://www.hobbyking.com/hobbyking/stor
... duct=11903
The weight of my completed EPP combat plane without battery is 8.1oz
(231g). A new BP Fun Foam without battery weights about 7oz; my white
BP Fun Foam with a few weeks' worth of glue repairs weighed 7.9oz. My
grey blucor Top Gun Foam Warbird weighed 8.1oz when first built. So,
the weight of the EPP combat plane looks OK.
I've test flown it with a streamer and it has plenty of power and
maneuverability. The control is little less "crisp" than the BP Fun
Foam planes, but the durability will be much better.
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