EPP SU-39 (modernized SU-25 Frogfoot) formerly: lets play "guess the plane" - Page 2 - RC Groups
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Sep 19, 2010, 03:36 AM
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Mr. UD's Avatar
Thanks for the tip - I will use two 70A ESCs - have been reading about the high consumption in the review area of HK: several ESCs have been victims oft these EDFs
A 3s 5000mAh accu should handle the power too.
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Sep 19, 2010, 09:39 PM
up up and away
Mr. UD

Your welcome. I'm curious to see how this one fly. Do you have an idea of what your auw will be?Wingspan? Your T-50 project would of been a nice choice for the edfs. I like the way you made that.
Sep 20, 2010, 08:01 AM
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Mr. UD's Avatar
Thanks for the commendation!

I hope the SU will be below 2kg (1,5?); wingspan is 1250mm without pods.

Havent had much time to proceed at the weekend (I'm living in munich ) but the right fuselage is carved/ sanded and the forward wing-bulkhead is ready to be installed - hope to finish carving of the left nacelle today.

..next is the installation of the ducting made of thin plastic sheet - hope this will work the way I expect.
Sep 21, 2010, 12:53 AM
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Mr. UD's Avatar
...inside of left nacelle is carved and sanded. Today I proceed with the outside and the ducting.
Oct 01, 2010, 12:57 AM
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Mr. UD's Avatar
Lots of progress but no camera :
-carved and sanded fuselage, canopy, back and nacelles
-build forward and rear wing-mounting spars and brackets

Today I will start to build the wing:
-cutting slits for the spars:
rear spar 75mm from the TE; D6x1,25mm carbon tube
forward spar 185 from the TE; D5x0,5mm carbon tube

Not sure about the aileron size: span of 230mm (25% depth) would be scale but 310mm would give more roll control (beside that at scale-sized ailerons I could install flaps too??? weight <-> lift/gadget )
Oct 14, 2010, 12:06 PM
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Mr. UD's Avatar

fnally some pics

Finally I was able to borrow a camera and make some pics of the actual progress:

wing and center section:
-center section parts are glued together and shaped
-slits for spars and wing brackets are melted/ cutted into the center section
-slits for spars are melted into the wings

-all parts are glued together and shaped
-cutouts for elevator-servos and cable tunnels are done
-canopy is roughly shaped
-nacelles are glued on and shaped
Oct 15, 2010, 05:56 AM
Pointy end at the front.
benjo's Avatar
CoooooooooooooooooooooooooooooLLLLLLLLLLLLllllllll llllllllllllll

makes me REALLY want one, i love russian planes. Good job!
Oct 16, 2010, 10:26 AM
Vozdushno Desantnie Voiska
specnaz's Avatar
very interesting build
Oct 15, 2011, 12:49 PM
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Mr. UD's Avatar
... after finishing my Nemesis Air Racer and my Henschel HS-129 B3 I decided to finish my SU-39 too - I will start with it tomorrow after a break of almost exactly one year!
Last edited by Mr. UD; Oct 15, 2011 at 01:20 PM.
Oct 15, 2011, 01:55 PM
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LuvEvolution7's Avatar
deffinitely subscribed. what an awesome plane.

did you ever do anything about coating the duct walls? if not, have you considered something like a one part liquid polymer, or two part liquid polymer coatings? it's as simplw as paint on and let dry to a hard, smooth finish.

if you want a cheaper solution, I like coffee filter paper and Water Based Polyurethane. brush the WBPU ont he foam and then lay your cut pieces of coffee filter paper down, then saturate with more WBPU. let dry and it'll be smoother than the foam surface. if you go this method, I would work from the exhaust to the inlet, since you'll have to overlap the pieces of filter paper. going from front to back will make sure that the aird doesn't lift the overlaps.

another option is to use pieces of poster board or brown paper, cut to size, then glue them to the foam underneath. this is less work, but probably won't last as long.
Oct 17, 2011, 08:50 PM
if you see a weed, pick it
malakiblunt's Avatar
This is looking great, intreasting subject plane but should also be a realy good flying model. Your Henschel inspired me to start my own EPP scale build a Heinkel P.1078c

Oct 18, 2011, 01:43 PM
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Mr. UD's Avatar
@LuvEvolution7: I didnt decide how to cover the intakes yet - but I guess I will try the plastic-sheet version first because it is the least time consuming version - if this will fail I will try your recommendations

For motivation I did the work package with the most visible progress first: so I started work with the wing. I marked the the ailerons, flaps and the cutouts for the associated servos (4xHXT900) and carved out the cutouts and the cable-channels. Next will be the soldering of the wing-harness and the assembling of the wing spars.
Nov 06, 2011, 06:19 AM
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...lot of progress:
- cutted out ailerons and flaps
- hinged them with UHU-POR
- soldered the wing-harness (2 aileron and 2 flap-servos connected to the fuselage-harness via a single 5-pole balancer-plug)
- glued in the main and secondary-spar
- attached the aluminium-reinforcements
- cutted, carved and glued on the wingtip - ECM - pods
- cutted the pylons and their bottom glass-fibre reinforcements (0.3x5x150mm)

- soldered the fuselage - servo harness (2 elevator-servos, 2 controllers and the connection to the wing-harness)
- soldered the power - harness

tail surfaces:
- carved the LE, TE and HL of the horizontal- and vertical tail surfaces
- cutted slots for the carbon fibre spars (5x0.5mm) of the horizontal- and vertical tail
- cutted and carved the doublers at the bottom of the vertical tail (rear missile warner)

..pics will follow
Nov 12, 2011, 06:04 AM
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Mr. UD's Avatar
...attached the pylons to the wing and installed reinforcments (3mm ply-floor and 10x0,5mm CfK-longerons) in the accu-bay.

...and finally here are the promised pics of the actual progress:
Nov 12, 2011, 09:34 AM
if you see a weed, pick it
malakiblunt's Avatar
Looking great, so many pylons! are those magnets to hold on the stores?

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