Ultimate-Jets

Ultimate Jets PNP Rafale

This is an article detailing the manufacture of our new mk II PNP Rafale from the AD JEts empty shell.

 

The gear:

 

 

 

 

 

Written by Olivier Nicolas — July 09, 2015

New Gen 5.5 Mibo A-10

Dear all.

This is a blog introducing the new Mibo Gen 5.5 A-10.

 

 

Although the kit has been on sale for a couple of months now, it took me some time to get the pictures of the upgrades and modifications to show you.

The Gen 5.5 main features are:

  • Lighter layup and maximum thrust allowed 140N.

A couple of areas where optimized with a different carbon fabric and orientation. A slight change in bulkhead design and position enabled a slightly lighter aiframe.

  • Main gear struts molded from Epoxy resin.

This reinforces the attachment points of the gear doors. The door pushrods are now 100% scale.

 

 

 

 

The dampers are now 3 spring progressive units instead of previously 2.

The brakes are upgraded to larger gen 2 discs with 5 holes. However max braking weight is still limited to 25 kgs/ 55 lbs.

 

 

 

  • New install kit for Behotec B-100F with streamlined 6 degree pipe.

This optimizes the trust line and virtually eliminates the pitch down effect found on bigger engine options. Also since the thrust tube is streamlined with the engine, no thrust loss is present . This setup provides the same thrust level as the 140 N engine with a weight saving of about 4 lbs ( lighter engine, no ballast weight in the nose, smaller fuel tanks ).

The picture below shows the areas modified from the previous gen in grey.

 

 

 B-100F installed:

 

 

  • MIL Spec loom: this option is available for the B-100F ( engine loom ) and the servos ( conventional receiver type loom ).

Engine loom:

It uses our MIL SPEC light weight silver/ PTFE wires as well as 12 way USC connectors for the pod interface. The loom is protected with our high temperature MIL spec wrap-around sleeve and labeled at both ends with aero grade printed heat shrinks. All connections are machine crimped and labeled.

The fuselage pods can disconnect within seconds with 1 plug, rendering maintenance and transport very easy.

A view of the engine pod USC which connect COM, starter and plug power lines.

 

 

An engine accessory tray is provided with a set of turbine accessory holders fro the B-100F. It houses the JMP Medium air traps, ECU, pump and valves. It is placed in front of the fuel tanks and main wing bulkhead for CG optimization.

The long tubes to the engines are on the pressure side of the pump. Tubing upstream the pumps are of minimal length and use large bore Tygon to avoid cavitation.

 

 

Servo loom.

It consists of 3 harnesses. Right wing, left wing and tail.

The wings are connected with our 20 way USC. The fuselage side is using a flanged plug that is screwed with two button head sheet metal fasteners.

 

 

The wing side is using one floating male plug.

 

 

The 20 way USC connects: all wing servos, the LEDs, the gear lines, the brake lines. No other connection is required.

The tail loom uses one 16 way USC plug. It connects: 2 rudder servo, 2 elevator servos, 2 LED lights.

The loom comes fully crimped and protected with our MIL spec wrap around sleeve.

It is fastened into the fuselage by the means of our PYCABS clips.

 

 

All the servo plugs are machine crimped JR type industrial grade MOLEX branded. All servo ends are labelled with aero grade printed heat shrink labels.

 

The wrap around ends are stabilized with woven heat shrink tubes and siliconed. The loom can be opened, modified and re-closed at the user's convenience.

 

  • New scale accessories: A new top fuselage antenna is provided.

The new antenna kit is as below:

 

  • New LED kit:

The new kit includes 100% scale 3D printed wing tip and tail light fixtures. The LED kit is now utilizing only super high brightness LED lights and is unique on the market. It is triple the power available on the previous set and requires a dedicated 2S Lipo pack due to the high amp drain of the LED.

 

 

A new wing tip light feature is 3D printed to house the new high power LED.

 

 

The nose gear taxi lights are re-worked and a bit more scale.

  • New operating side hatch for switch. This side hatch has been made operating to enable fitting your main switch ( RX switch ). It features a piano hinge and magnet.

 

 


  • USB Servo mounts: the kit comes with a set of PYCABS printed servo brackets custom sized for the JR 8711 servo which is the recommended item for this plane.

 

  • Deceleron: Fully functional split ailerons are being tested right now and will be released very soon.

 

Here is a video of dry fitting the A-10 out of the box:

 

 

And a few detail pictures:

 

 

 

 

 

 

 

Written by Olivier Nicolas — April 18, 2015

AD Diamond gear assembly and fitting.

Here is a quick review of the gear fitting.

Assembling the gear is fairly straightforward.

I will show the steps required to assemble the Behotec e-Tract gear.

 

Kit content:

 

3 e-Tract retract units

3 struts ( trailing link type )

3 tyres

One controller/ cables bag ( e-tract controller, display unit, male-male cables )

One direct steering servo mount bag ( optional )

One main wheel rims and e-brakes bag ( including 2 friction plates and 10 socket head screws )

One front wheel rim bag ( including 5 countersink philips head screws and the strut shear pin)

One bag with 2 main struts shear pins and 2 main wheels screw type axles/ nuts.

 

General considerations:

 

Use thread lock on all screw assemblies.

 

Wheels assembly:

 

Locate the wheel component and unpack.

Place the wheel rims on each side of the tire and align the 5 fasteners holes.

 

 

Insert the socket head screws ( main wheels ) and countersink screws ( nose wheel ) in the countersink holes and fasten.

Note that the socket head screws are protruding on purpose to hold the e-brakes friction plate in position.

Fasten the screws in a star pattern to ensure that the rims are being pressed face to face flat.

 

 

Assembling the wheels on the struts will require to assemble the e-brake system for the main wheels.

Locate the e-brake components and unpack. Remove the two friction plates from the paper protective bag. Degrease before assembling.

 

 

Place the friction plate in position through the 5 protruding socket head holes.

 

 

Insert the wheel axle socket head screw through the rim and place the brake assembly hub against the friction plate.

ATTENTION: from this point on, always ensure that the friction plate stays seated against the wheel rim when you move the wheel.

 

Place the wheel against the strut and fasten, ensuring that the electric cable is exiting rearwards as per the picture below.

When tightening, verify that the wheel can still rotate freely. Clearance vs friction ratio must be setup at this stage. A slight play is normal and helps the friction plate to release after braking action is finished.

Once appropriate clearance is achieved, place the counter nut in position as per the picture below and secure tightly. Do not forget to add thread lock on this nut!

 

The nose wheel will be place into the nose fork of the front strut. Note that as the rim has a slight recess on one side, two tube sections of different length are supplied to center the wheel. The short tube section goes on the recessed side of the rim as per the picture below.

 

Once the short section of tube is placed on the wheel, take the axle and insert on the non thread side of the fork, facing upwards. Leave only a short section of the screw extending through the fork side. Insert the long section of the tube into that short section, then place the wheel with the short tube on top through the fork, holding the assembly with one hand from the top ( refer to picture below ). Center the tubes and push the axle all the way though to the threaded side of the fork. Fasten with thread lock fluid. Once again, the ration clearance vs friction will be set while securing the screw.

 

Struts:

 

Insert the set screws on the trunion and on the strut. Insert the shear pins all the way in. Fasten moderately as the toe will be adjusted later on, when set on the plane.

Note that the nose strut is secured by a collar that mounts on top of the trunion. Ensure that the 45 degree routing on the collar is facing outwards as it is designed to clear the wall area. Also ensure that the top of the shear pin does not extend through the collar at all as it might bind against the screw jack otherwise. Even a small amount of protruding pin could jam the nose retract. Ensure that the set screws of this collar are firmly tighten and thread lock is applied.

 

Servo direct steering:

 

Locate the steering servo mount accessories bag and open.

Install the servo bracket on the side of the trunion as shown on the picture below. The two socket head screws will require firm fastening to ensure that the bracket does not move when the servo is operating.

 

Install the brass ball on up most the set screws holes of the strut and insert the strut into the shear pin.

Fasten with thread lock and install the other set screws to secure the strut.

 

 

The servo bracket is set for standard JR servo size of 39.8 mm. For Futaba standard servo, you will have to trim the bracket by 0.2 mm. Use an electric file or a tungsten carbide rotary file for this job.

Once the servo is installed, setup the pushrod by installing the two ball links on the threaded rod and trimming it to the appropriate length.

 

The servo arm ball link should be set at the second hole from the center. Check the arm travel does not push any of the two ball links out of their respective balls. Also make sure that the link stays flat on its ball.

 

Fitting the gear in the plane.

 

The gear is supplied with the trunion in the retracted position. Before mounting the gear, you'll need to extend the struts. To do so, plug each retract unit onto the e-controller on the MOT 1-3 position. All the plugs should be facing the same way. MOT 3 is for the nose gear retract. Plug the gear battery ( a Lipo 2S or A123 3S unit is sufficient ) and a servo tester control unit along with a Rx battery. Move the control switch from down, which should give a servo output of -100% to up with a servo output of+ 100%. The gear should now drive into the extended position. If not, invert all the plugs and try again.

Mount your extended gear using the socket head screws supplied.

Install the retract and e-brakes harness so that it never gets pulled when the gear is moving.

Once the gear is mounted, inspect the retraction path and the gear bay opening. You must ensure that the bay opening is wide enough and nothing will obstruct the retraction motion. Check the trunion, struts and wheels. The do a first test one strut at a time: retract one strut and be ready to disconnect the gear battery when it approaches the bay opening. Once this is done, check for clearance and trim if necessary. Then re-plug the gear battery and let the gear retract further till the next low clearance point. Apply the same procedure again till the gear is fully retracted. Pay a special attention about the wing/ fuselage internal ribs/ bulkheads at the end of the travel. We recommend to ensure a minimum of 2,5 mm / 1/10" clearance from the airframe at all times.

Proceed the same for every strut till you are 100% satisfied that the appropriate clearance is ensured all around. Also check the harness clearance and tension during this process.

Then extend the gear again and check for the main wheels toe. Adjust if necessary. To lock the toe angle, we recommend the following:

    1. Cut two slots on the trunion part of the shear pin at the set screw location with a dremel cutting wheel. Fasten the pin in the trunion.

    2. Degrease the shear pin part that goes into the strut. Put one drop of low strength thread lock on this part. Insert into the strut and adjust the toe. Fasten the strut set screws firmly without overstressing the thread. Let the thread lock dry before use.

       

         

        Retracts setup:

         

        The gear setup is fairly easy.

           

          1. Make sure that the channel you are going to use is set at +- 100%

          2. Plug the gear output and brake output on the controller

          3. Power up the receiver and plug the gear battery

          4. Activate the gear switch both way wait 2 seconds between each switching. If the gear does not move, invert the gear output plugs from the controller unit. If the switch is inverted, change the travel from the transmitter. If the gear stops before it is fully extended/ retracted, have a look at the display. If it shows a lightning symbol, then the gear is binding. Check for hard point/ rubbing/ binding. If the display shows a T, then the gear stopped due to timeout. Increase the timeout delay.

          5. Setup your brakes. Plug the left brake on output 1 and the rigth brake on output 2. The middle cable of the 3 way plug SHOULD NOT BE CONNECTED. Enter the brake setup menu to learn RC and set the no brake position as well as max brake position.

          6.Now check the braking power. Activate the brakes from your transmitter to full position. Move the model on a surface representative of your runway ( concrete or grass ). The braking power should be so that the wheel are about to lock. If they are locking when you push the model hard, decrease each brake setting ( brake 1 is usually for the left main wheel and brake 2 for the right main wheel ) slowly till satisfactory. On concrete, the Diamond will require about 60% braking power on each wheel.

           

           

             

               

                 

                   

                     

                    Written by Olivier Nicolas — February 26, 2014

                    Superphoenix assembly day 3: the wings

                    The wings assembly is quite straightforward.

                    Install all 4 servo in their covers using the supplied hardware. I add a string of Sikaflex silicon glue to the servo strap to improve the servo fastening.

                     

                     

                    Place the servos into their pockets. Additional trimming might be required at the servo cable exit location. Drill the wing at the cover holes location. Place the pushrods on the servo arms and fasten the servo covers on the wing.

                     

                     

                    Check the position of the control horn slots into the flaps and ailerons. They should match the position of the pushrods. Routing the slots might be necessary if they appear too short.

                    Scuff the control horns and make a few drills in the gluing area. Identify the proper horn shape before placing them on the wing.

                    Aileron control horn:

                     

                    Flap control horn:

                     

                    Rudder control horn:

                     

                    Glue the horns in their respective slots with Hysol E20HP.

                    Once the glue has cured, place the pushrods and set them up to ensure that the control is at zero with the servo arm at 90 degrees from the pushrod.

                    Place the wing loom in position.

                    Route an oval slot in the wing root to allow the positioning of the EWC6 connector.

                    Slide the wing tube into the fuselage/ boom assembly. Center it

                    Place the wings in position onto the booms and fuselage. Make sure that then are a snug fit.

                    Drill a hole through the wing fasteners holes and the wing tube The drill bit should be 2,5 mm.

                    Remove the wings and tap the wing tube at M3.

                    Refit the wings and verify that the M3 socket head crew fit correctly.

                    Drill a 2.5 mm hole into the main fuselage bulkhead through the wing sleeve and wing tube.

                    Tap the wing tube at M3 and redrill the bulkhead/ sleeve at 3 mm.

                    Place a M3 socket head crew into the bulkhead to fasten the tube from the center.

                     

                     

                    Written by Olivier Nicolas — October 06, 2013

                    Superphoenix assembly day 2: booms and elevator.


                    I started with the booms and elevator servos. You will notice on the following pictures that the rudders feature a carbon fiber tab. This is a specific setup for the Superphoenix version that is optimized for hovering and 3D aerobatics. The rudders have their surfaces increased by 30% with this tab.

                     

                     

                    I started with the rudder servos by putting them in their aero cover. It is a straightforward operation and the only specific thing I do here is to add a thin string of Sikaflex silicon glue on the servo strap before fastening it in position.

                     

                     

                     

                    Once the servo got in the cover, I placed it in the corresponding pocket on the boom to mark the areas that would need a bit of trimming. That was mostly at the servo wire exit.

                    I also drilled the cover holes for the small countersink screws.

                     

                     

                    I then checked the control horn slot for compliancy. In this case ( prototype #2 ) the slot was not properly placed on the boom, but was OK on the elevator although a bit short. So I marked the proper location and routed the appropriate slot for the horns.

                     

                     

                    I then glued the control horns in position for the elevator and booms.

                     

                     

                     

                     

                    And the final result:

                     

                     

                     

                    The servo cables for the booms and elevator will have to pass through the boom spar. There is a reservation for these cable made in the spar at the bottom of the boom. Passing the cable through that reservation will require you to make a long hook from a piano wire.

                     

                    Note that I will make a MIL spec loom for this plane as I have done with the Scorpion Mk2.

                     

                    http://www.ultimate-jets.net/collections/aviation-design-scorpion-mk2-accessories/products/scorpion-mk2-mil-spec-loom

                     

                    The elevator is fastened in between the two booms by a set of aluminum pns and one M6 nylon screw per side.

                    The nylon screw insert tends to get clogged with some gelcoat. A quick de-burring with a X-acto will do the trick to allow an easy insertion on the M6 screw.

                    Similarly the aluminium pins must be fastened in the corresponding inserts and might also require some de-burring.

                     

                     

                     

                     

                     

                     

                     

                     

                    Written by Olivier Nicolas — October 05, 2013

                    AD Diamond build thread. Presentation

                    The first production airframe is on the way to me.

                    This is still a prototype stage kit but we will use it to fine tune the production process.

                    All the internals on this model will be identical on the production kits. So I will take the opportunity of this build thread to show you how this model is made of.

                    Here are a few pictures of this exact airframe during the production stage.

                     

                    The wings:

                     

                     

                    The main spar up to the landing gear plate is made of aero grade Finnish birch plywood. The main spar is 12 mm thick and virtually indestructible. The gear false ribs are also made from the same ply.

                    The rear flight control spar is made of thick balsa wood. The wing skin is vacuum moulded from drilled Airex/ glass fiber sandwich with a thick carbon fiber patch joining both the main and front spars.

                     

                    The fin:

                     

                     

                    The same type of construction is used for the fin: vacuum moulded drilled Airex/ glass sandwich with thick aero grade plywood main and rear spars. Eric took a special care at sizing this area as the horizontal stabilizer is mounted on top of the fin and it is essential that the whole assembly stay super stiff in all situations.

                    The top of the main fin spar has a T shape that includes two ribs and the small tube section required to  slide the two half horizontal stabilizers. The stabilizers tube is in one piece.

                     

                    The wing, rudder and stabilizer tubes are made from aero grade AU4G that is used on AD drones as well as all the models from the Scorpion to the super scale Rafale.

                    Written by Olivier Nicolas — October 02, 2013

                    Super Phoenix assembly day 1: introduction.

                    I recently received the brand new MK2 Super Phoenix from Aviation Design and wanted to share the buil and flight tests with you.

                     

                    This plane is my baby and I worked on this new version for about 4 years through two prototypes.

                    The very specific feature about this plane is that the rear fuselage and boom area are CAD designed to create a venturi effect when the engine is at full power and the plane is standing still in the air. This venturi effect creates a flow of air around the rudders and elevator, enabling to control the plane during hovering without an vector thrust system or gyros.

                    The kit came in a fairly reasonably sized cardboard box that was quite easy to handle.

                    The manufacture quality is the same as the Scorpion Mk2. The plane is produced the Czech republic from drilled Airex and high quality fabrics and epoxy. The plane comes painted in the moulds.

                     

                    • New moulds CNC cut with perfect moulding plans
                    • Aero grade plywood/ liteply formers CNC cut and precisely adjusted.
                    • Drilled Airex composite sandwich.
                    • Airframe painted in the moulds using aero grade gel coat.
                    • New Stabilizer and rudders improved for 3D flights
                    • New live hinging technique using specific hinging nylon ribbons

                     

                    The plane was CAD designed from the previous paper drawings and optimized for 3D maneuver. All the formers were re-designed for optimum weight saving.

                    It is the only plane in the world to be able to hover and to perform basic 3D maneuvers WITHOUT THRUST VECTORING and WITHOUT GYROSCOPES. The speed range on this model is also unique since it can fly from 0 mph ( hovering in front of you ) to 300 mph in a full power pass with our B100F.

                    Bear in mind that due to these exceptional performances we require the customer to fly the plane with a GPS feedback enabled system to comply with the AMA/FAA regulations, including speed and height restrictions.

                     

                    Here are a few pictures of the Swiss scheme model I received a few days ago.

                     

                    The model assembled in my workshop:

                     

                     

                    A few details of the fuselage inner structure:

                    The front and rear main formers have been carefully CAD designed for optimum strength and weight saving.

                     

                    The main former at the wing to gear plates junction. Note the carbon fiber reinforcement strips:

                     

                    The drilled Airex is visible at the bottom.

                     

                     

                    The nose gear structure:

                     

                     

                    The main radio tray structure:

                     

                     

                     

                    The weights are as followed:

                     

                    Fuselage: 1750 grs

                    Right boom: 330 grs

                    Left boom: 310 grs

                    Left wing: 454 grs

                    Right wing: 478 grs

                    Stab: 250 grs

                    Kevlar tank: 163 grs

                    Wing tube and accessory pack: 400 grs

                    Servos and receiver: 360 grs

                    Batteries: 350 grs

                    Merlin VT80 all up and 5 min of fuel: 2400 grs

                    Or B100F with 5 min of fuel: 3000 grs

                    Behotec gear: 900 grs

                     

                    This makes a total of 8145 grs for the VT-80 option ( 80 N of thrust ) and should be just enough to enable the plane to hover.

                    However that makes a total of 8745 grs for the B100F option ( 120 N thrust ) and will ensure a thrust margin of 37% above its own weight for stratospheric performances.

                    I have flown this configuration on my previous Super Phoenix that was about 1 kg heavier and the performance of the aircraft was outstanding.

                     

                    Written by Olivier Nicolas — September 07, 2013

                    Scorpion MK2 assembly day 9: flight test.

                    Here is my report after the test flight period.

                     

                    A previously explained, I went through a complete routine of system tests with the Scorpion before doing the test flight.

                    The first round consisted of ground range tests with the engine OFF then with the engine running. Once I was satisfied with the performance of the Weatronic system, I went for a taxi test.

                    I started with the brakes system power reduced to 70% and did some high speed rejected takeoffs. Ended up reducing the brakes power to 50% to avoid locking the wheels.

                     

                    All the other controls performed as expected during this test, so I went ahead for a first flight.

                     

                    The program of the first flight was as followed:

                    takeoff, climb with gear down and takeoff flap setting, stall, recovery from stall, second pass at high altitude with landing flaps, stall, recovery from stall, descend to circuit altitude, trimming, one touch and go and flap retraction to takeoff flaps, one full stop landing with landing flaps.

                     

                    The stall speeds from this first test flight were: Vsf15= 62 kph,

                    The readout of the stall speed at flaps 15: 47 km/h + 15 kts head winds.

                     

                     

                    Vsf30= 54 kph.

                    The readout of the stall test flaps 30. 44 km/h + 10 km/h of head winds.

                     

                     

                    This enabled me to set the approach speed at 1.3Vs as followed: 70 km/h

                    This is the speed that I  have entered as min speed in the Weatronic voice system as min warning.

                     

                     

                    Top speed test was done later on flight 5 with several passes head wind and down wind. The average of two consecutive passes gave me 248 km/h or 154 mph.

                     

                    Here is the data readout of these two passes:

                    Down wind pass at 262 km/h:

                     

                    Next head wind pass at 234 km/h

                     

                     

                     

                    The Merlin VT-80 does a perfect job on this airframe by keeping it light and efficient. Don't forget that the VT-80 features the best power-to-weight-to-price ratio of the market and is incredibly reliable and  extremely well built. The engine specific consumption is so low that I recommend using our 2.2 l kevlar tank.

                    This saves another 2 lbs at takeoff weight.

                    http://www.ultimate-jets.net/blogs/jet-engines/7716295-choosing-the-right-engine-for-your-application

                    I have done all the Test flights in Dubai by 110  F temperature and with a pressure of 995 Hpa. This gives an density altitude of about 4000 ft and the thrust available is 70N/ 14 lbs in these conditions.

                    However, takeoff occurs within 50 meters with flaps 15. Aerobatics capability and performance is excellent with this combo.

                    The plane is very easy to  land as one can see on the numerous videos I posted recently.

                     

                    Scorpion Mk2 flight 5 from Oli Ni on Vimeo.

                     

                    Scorpion Mk2 aerobatics part1 from Oli Ni on Vimeo.

                     

                    Overall it is a great looking airframe, featuring a manufacturing quality among the best in the world, very easy to fly and able to perform most aerobatics maneuvers, including snap rolls. The VT-80 combo is fantastic, giving a very light weight and making the plane very easy to setup and maintain.

                     

                     

                    Written by Olivier Nicolas — September 01, 2013

                    Scorpion Mk2 assembly day 8: Final steps.

                    This is the final stage of the Scorpion assembly.

                     

                    It involves installing and drilling the wing tube, the fins, setting the batteries and installing the receiver.

                    My receiver choice went for the Weatronic micro 12, which I consider as being one of the best device on the market for a great price. It offer invaluable features to me like data logging and advanced flight analysis which enables me to validate the flight tests.

                     

                    The switch is an Emcotec BIC v2. A nice device that works as a battery backer, voltage regulator and capacity counter. It works pretty much like a Kodiak system and is very handy for A123 elements.

                    It also gives indication of each battery voltage, actual used current and total capacity used. That is interesting when testing the electrical system before maiden. I have used the BIC for many years in hot/ desert conditions in Dubai and never had a problem with it.

                     

                     

                    The wing tube is very easy to install. It is just a matter of centering it in the fuselage and drilling the center through the main bulkhead to fix it. Then the wing panels just need to be assembled and the tube drilled through the pre-made hole. Really a matter of minutes.

                     

                     

                    The same process goes for the fins. It takes a little bit more time as there is no driling mark on the fuselage. You'll have to make sure that you will drill through the tube and not outside of it. The best technique I found was to use a powerful LED flash light to highlight the tube area by transparency from the inside of the fuselage. Worked out very well and it only took me a few minutes to find the drilling sweet spot. I used countersi

                    Cutting a countersink recess in composite laminate. from Oli Ni on Vimeo.

                    nk screws for the fins that come flush on the fuselage.

                     

                     


                    The batteries have to go into the nose. I used two ThunderPower 3700 mAh LiPo batteries for the receiver and one 4000 mAh LiPo battery for the engine. A typical flight burns 200 mAh so I guess that two 2000 mAh battery would be largely sufficient for a good afternoon of flights. Similarly a 2500 mAh ECu battery would be sufficient as well. With the heavier batteries I used, I have to place them as far aft in the nose section as I could. Lighter batteries could go further forward in the long aircraft nose.

                     

                    The aircraft setup should be done according to the user manual. The throws are good and the only thing I did not implement was exponentials. At 155 mm, the CG is fairly fore and the model certainly feels nose heavy, but I still recommend to start with this setting to get used to its flight characteristics. It makes the Scorpion very stable and very easy to fly. Also the plane does not stall at this CG.

                     

                     

                     

                    I went for a full battery of tests before the first flight, including fuel system test, engine test, electrical system test and range test. All was perfect and the maiden went very smooth.

                    The electric gear together with the VT-80 make this airplane extremely easy to setup at the field. It is just a matter of bolting the wings and filing the tank. I get the plane ready within 5 minutes after I arrive at the field and similarly the car is ready to go in 5 minutes after the last flight. Very convenient for those who have the family waiting at home!

                    Written by Olivier Nicolas — August 31, 2013

                    Scorpion Mk2 assembly day 7: engine and fuel system.

                    The engine install described in this section is with our Merlin VT-80.

                     

                    This engine is simply fantastic. It is extremely reliable and features the best thrust to weight to price ratio on the market. Additionally this is one of the most integrated engine. The only accessory that is left outside of the engine is the fuel pump. ECU and valves are located under the inlet cowl. This makes a very clean install and clears up most of the radio tray surface as you will see later. Also the engine setup is extremely simple and is a matter of seconds.

                    The first step is to install the Grumania pipe provided with the kit. the long aluminium tab is designed to secure the bellhousing. However I recommend to add two miniature screws placed at 120 degrees at the bottom of the latter for additional securing. The pipe itself will be secured from the side of the bellhousing thanks to two sheet metal screws going into the plywood engine rail. I actually added two hardwood blocks to the rails at this location to make the drilling easier.

                     

                     

                    On this picture one can see the hard wood block as well as the sheet metal screw.

                    Note that it is important to install the engine first before securing the pipe to adjust its position properly. However I found out that the Grumania pipe is very tolerant to the engine placing. In my case the VT-80 nozzle is flush with the bellhousing entry. I have tried positions up to 35 mm inside the bellousing with no notable difference in thrust or engine/ pipe cooling.

                     

                    The VT-80 being quite narrow, it requires extension tabs to mount on the rails. I used pieces of 3 mm carbon fiber laminates cut to the appropriate shape. 6 socket head sheet metal screws are used to fasten the tabs to the rails.

                     

                    The engine is placed as far to the rear as possible to facilitate CG placement. With this setup there is actually no balancing lead in the nose and the LiPo batteries are placed as far aft as possible in the nose bay. The FOD screen used is the one provided by Jets-Munt.

                     

                    The VT-80 pump is place on the right engine rail, close to the engine. Both fuel pump feeder line and exit lines are short.

                     

                    The engine loom is protected by our MIL spec wrap-around cable sleeve and will not suffer from an overheat condition. The loom consists of the power leads, a radio input cable and a terminal output cable. The terminal plug is located on the radio tray. The VT-80 terminal is very small and could be left inside the plane. However the engine is so dependable that I don't use it anymore and permanently removed it from the installation.

                     

                    The fuel tank shown below is the 3.2 liters version. This gives a fuel endurance of 20 minutes which is a bit overkill. I have installed a 2.2 liters tank since then and saved a substantial amount of weight at takeoff weight, making the Scorpion Mk2 performance with this engine very convincing.

                     

                    The tank is secured a the front thanks to a couple of rubber bands. The rear is locked with a foam block velcroed on the main bulkhead.

                     

                    I used the excellent GRB Jet medium size CAT on this setup. The air trap is located at the rear of the tank above it. It is secured with some velcro and a custom cut foam block.

                    The servo wire that you see passing above it is the speedbrake cable. It is long enough so that I put the engine hatch on the wing without having to disconnect the servo plug.

                     

                    Here is a view of the rear block.

                     

                    I really strongly recommend the VT-80/ Scorpion Mk2 combo as it makes a fantastic machine.

                    Here is how the installation looks like with this combo:

                     

                     

                     

                     

                     

                     

                     

                     

                     

                     

                     

                     

                    Written by Olivier Nicolas — August 23, 2013

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                    We are the one and only USA based turbine powered UAV and hobby models manufacturer. Ultimate jets offers some of the best engines, kits, and accessories to the Industry. ................................................... We offer in-house design and manufacture services for military and hobby companies. Our expertise extends from aero dynamics design to carbon fiber aerostructures manufacture and 5 axis CNC milling and turning. ................................................... We are the USA distributors for Behotec, BF-Turbines, Mibo and Aviation Design and provide in-house support and service for these products. ................................................... We also are dealers for the following brands: Jets-Munt, Permagrit, Ultratool, Cotronics, Techflex and many other aerospace industry suppliers. ................................................... We finally house a unique technical blog that you will find below, providing industry reference articles. Please feel free to browse through these pages. Enjoy... Barry, Woody, Shaun and Oli.