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Old Feb 19, 2015, 07:04 PM
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Build Log
TechOne EPO Sbach 342 PNP from BuddyRC

This will be a build log and review for the TechOne EPO Sbach 342 Thrust Vector Indoor/Outdoor PNP Aircraft from BuddyRC. The airframe and batteries for this build log and review were provided by BuddyRC.com I have been an Ezone / RCGroups author since 2001. I usually would do a formal RCGroups review of airframes that are provided for review , but in talking to BuddyRC they wished to do this review as a build log.

A link to the review aircraft can be found here:
http://www.buddyrc.com/techone-sbach...-aircraft.html

Specifications:
Wingspan...............840mm (33.1 in)
Overall Length.......960mm (37.8 in)
Flying Weight........275-295g (with battery)
Prop Size..............8x4
Motor Size.............AT2206/V2 KV1500
Speed Control.......10A
Servo.....................9g servo (4 pcs)

Recommended Battery....... Glacier 3s 11.1v (Sku:GLC-25C-450-3S)

As a PNP aircraft all of the components outlined above are included with the kit. A receiver and battery will need to be provided by the modeler.

My first impression was that this was a rather attractive model and upon further inspection felt fairly light for its size and epo foam composition. After handling the airframe for a few minutes while going over the parts, I soon began to worry about how long this model would look attractive ... the decals were already beginning to peel somewhat.

For a (mostly) profile airframe, the Sbach has a very nice battery compartment and hatch that is held in place very securely with the provided clip at the rear of the hatch.

The motor and thrust vectoring mechanism is very securely mounted. I am really looking forward to see how this is going to fly!

Feel free to ask questions as I move along in the build!
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Last edited by kevin; Feb 19, 2015 at 07:28 PM.
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Old Feb 19, 2015, 07:04 PM
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Main Landing gear
The main gear are attached to the fuselage by inserting the end of the carbon rods on the gear into a plastic retaining clip on the fuselage. The gear fairing lines up with a recessed area on the fuselage and is glued into place.
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Old Feb 20, 2015, 08:06 PM
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WING
The wing is installed onto the fuselage by sliding it through the fuselage into place and gluing it. Note that there is one aileron control horn missing to allow you to easily slide the wing through the fuselage. There are also alignment tabs and notches on the wing and fuselage to help with alignment ... although the the modeler must still check for proper alignment. after the wing is in place the remaining aileron control horn must be glued in place.

HORIZONTAL STAB
The stab is slid into place and glued using a similar tab and notch design as the wing .. and as with the wing, the final alignment must be checked by the modeler.

RUDDER
As provided, the hinges are glued into the rudder. The slots for the hinges in the rear of the fuselage are factory cut. So all that is left to do is to slide the rudder into place and use ca on the hinges to glue it into place. Note: There is a small foam block that is glued into a slot at the back of the fuselage before the rudder is glued in place.
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Old Feb 22, 2015, 07:15 PM
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Wing and Stab Braces

Before the wing braces are attached, the wing fences are glued into slots on the bottom of the wings. The wing braces are glued into notches out on the wings. The other end of the brace (bare carbon rod) is glued into a plastic brace receptacle on the bottom of the fuse. The braces are also glued to the wing fences on the bottom of the wing. Note:The carbon rods are not glued into plastic brace tabs, so they must also be glued once all of the bracing is in place.

The stab braces are then glued in place in the corresponding brace notches.
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Old Feb 25, 2015, 09:02 PM
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Pushrods and control systems.

The ailerons and elevator are controlled by the servos with a carbon tube pushrod system. The clevises that connect the carbon pushrods to the control surfaces are held in place and adjusted with retaining screws. The elevator pushrod is run inside of pushrod guides that run along side the fuselage before it is attached to the elevator and elevator servo.

The rudder is controller with a pull-pull control system. The control lines are attached to the rudder control horns by tying them to the control horns and gluing the line to keep it from slipping or fraying. The lines are attached to the servo control horns by running the line through the outer hole in the servo arm and then securing it in place to the third hole in the servo arm with a retaining screw and washer.

Prop and Spinner

The prop is attached to the motor with an o ring system that is common on many indoor or park flyers. The foam spinner is attached to the prop by inserting the carbon spinner attachment rod into the spinner and then lining it up with the hole in the center of the spinner. The spinner is held in place with glue.

At this point the airframe is assembled. Now I just need to install the receiver, program the radio, and balance the model. I hope to be able to fly it this weekend at the local golf dome...
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Old Mar 01, 2015, 02:37 PM
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How does it fly? I had the TechOne Venus and it looks like it was made out of the same material. It few OK, but not great.
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Old Mar 05, 2015, 06:40 PM
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Honestly it flew ok but not how I was expecting. The issue I had was it was very tail heavy as provided. I needed to add 1.75 ounces of lead to the front to get it to balance just outside of the rearward mark, and it flew slightly tail heavy at that point. BuddyRC now has the airframe and is comparing it to their prototype which did not require the additional nose weight.
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Old Jun 29, 2015, 06:50 AM
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Mini Review and Comparison to Venus

Kevin, thanks for your extensive coverage of the build. It helped me a great deal.
Here's my little review on the Techone SBACH EPO with Thrust Vectoring.

First, let me say that I'll be making some comparison to Techone's Venus which is quite similar to the SBACH in scale and uses the same stock ESC and motor.

The Build:
Since Kevin has posted all the details, I'll just touch upon what I did differently. For those that have built the Venus; the SBACH is very similar, but slots together more easily. UHU Por was used for the entire build since it was on hand and the airframe was built in a couple evenings with some minor mods on a 3rd evening after test flights. Landing gear was not installed on mine since my field has very dry lumpy grass that tends to disagree with smaller scale wheels. A strip of 7 mil laminate film was used the line the bottom of the fuselage which helps greatly to protect the foam from scratches and dents during landings. Be careful not to iron it on too hot as EPO puckers with too much heat.

As many have done with the Venus, all the pegs on the control rod ends were cut/drilled out and replaced with bent "L" piano wire for the elevator and ailerons. Basically, 6 pieces. The little plastic pegs are extremely prone to breakage during flight, so the "L" wires take their place and are secured with the supplied red bands. This mod done on the Venus has lasted me over 3 years without replacement. I've also made bowsies out of truncated micro servo horns and installed them on the pull-pull rudder system instead of the recommended screw tension method. This makes the lines infinitely adjustable without tools (except your hands) at the field to get just the right rudder tension.

The 10a ESC was swapped out for a 13a with stronger switching BEC which did help a few initial glitches with overheating/thermal shutdown and sluggish servo response. Incidentally, the stock thrust vectoring servo had stripped gears and was swapped out for a metal gear servo of the same size. The added extra weight helped as the craft was definitely tail heavy. Some weight was added to the nose, but the recommended Glacier 450 mAh 3S batteries were later replaced with 850 mAh 3S ones and the weight was removed completely with the CG at 70mm past the wing leading edge. Please note that the 450 mAh Glaciers performed extremely well on the Venus on 8x4 prop however.

Programming:
The major draw for this model was the Thrust Vectoring feature. Initially, it was setup on my Spektrum TX for dual rudders; however, that prevented me from assigning the T.V. Servo to a switch to enable/disable it mid-flight. Thus, remapping was set to the Gear channel and an inversely proportional mix was set up with a 2-position switch relative to the Rudder. Please note that the TV Servo limits must be set to prevent the motor prop-saving retention screws from rubbing against the cowl. Expo settings were also setup for all control surfaces and range from 100% - 60% on a 3-position switch.

Flight:
The maiden was on a very mild day. I had mixed results with the stock setup and came back a little disappointed with the ESC and 450 mAh batts as the throttle seemed to decrease slightly when engaging the thrust vectoring feature; so I'd have to increase power a bit prior to moving the Rudder Stick. The EPO spinner with carbon rod also came off and I recommend putting just a dab of UHU Por/Foam Safe Cement on the part that contacts the prop; contrary to the instructions. The next flights were on a windier day with the 850 mAh batts and 13a ESC as mentioned above; but were much better. With a little adjustment to tone down the thrust vectoring endpoints, it really started to feel dialed in. I did try to fly with a 8x4.3 Slow flyer prop as well, just for comparison; and the stock 8x4 Direct Drive prop has a much more solid feel in the air. As I became more confident with the throttle management using thrust vectoring; the "dog chasing his tail" effect and ability to pull out of knife edge as slow speeds really got me hooked! It's also nice to be able to change direction from an almost 0 windspeed on the control surfaces. Disabling the T.V. is very noticeable and is nice for those maneuvers which need only Rudder input. Rolls for both the Venus and SBACH have almost the same quick responsiveness with the TV enabled being slightly different of course. Elevator input was similar as well. Landings were totally uneventful and I may split the Aileron servo into two units; as I did with the Venus to enable flaperons upon descent.

So how does this compare to the Venus?
The Venus has a noticeable "lighter touch" typical of indoor/outdoor 3D Planes, but the the Thrust Vectoring of the SBACH really makes it all worth it despite a heavier feel. Both airframes excel at basic 3D maneuvers with the SBACH being able to do a few more things rapidly. I'm not ready to retire the Venus yet, but am looking forward to many more flights with the SBACH.
More reports to come

-8th
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Last edited by 8thelephant; Jun 29, 2015 at 08:27 PM.
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