They say that good things come in small packages, well this one didn’t! The guys from Paritech did a great job of packing the kit and waiting at customs, I was greeted by a box that was 3meters long! I thought about it and saw that the only way to get this home was to tie it to the roof of the jeep – and that’s how it went right across Melbourne!
Taking the well packed parts from the box, the first thing that you notice is the extremely high quality finish on the glass work. All the wings are with virtually no imperfections, and the joining seams of the molding process are very neat indeed!
The 1/3 scale 5 meter DG 303 is available in various stages of completion, but I decided to get one that allowed me to mount all of the main components. You can get it all pre-installed and just add servos… its up to you.
Putting the wheel in
First up, working inside the fuselage. The very first thing I did was to place some carbon reinforcement round the soon to be cut retract doors. This will take some extra load if the doors were to strike something on the ground and also, to help distribute the loads from the retract. As always, the retract (coming from Fema) is a work of art. The Paritech guys also include all of the rubber mounting points, the gas strut for the suspension and the carbon reinforced mounting formers.
The hinges I used on the retract doors are nylon tube with spring steel hinge pins running the full length of the doors. The hinge point is placed 5mm in from the cut line to allow the furthermost part of the door to swing inside. Epoxy these in before cutting the doors, and make sure they are placed accurately. I added some carbon tows along the hinge tubes to give them some extra purchase.
As always goes with the apprehension of cutting into the fuselage on a nicely molded model, when working out the cut line (…well confirming the marks already supplied in the fuse) you notice that the seam on the fuselage is not in the centre! – This is actually correct! I understand it is part of the process of joining the two halves – so do not use the join seam as a centre line! I ended up doing some rather interesting measurements to make sure the molded markings were correct and started to cut. Using masking tape as the guide, and a fresh razor saw (having been recently introduced to this method by a colleague), the process is fairly quick and leaves quite an accurate cut line.
Once the opening is complete, you can locate the retract with its formers and epoxy those in. When mounting the base plate at the front of the retract, I also added some cloth over the top of the base plate to increase the bond strength to the fuselage. The retract servo was mounted to the retract using some aluminum right angle. Spending some time getting the geometry right with the control throws is well worth the effort for trouble free performance. Also (as I experienced), using a good quality retract servo is well work the investment.
Small items like the door jams (made from old scraps of fiberglass sheet), the pins for the door return elastic and hinge wire retainers can all be now fitted.
Tow release and nose
While working in that area, I installed a tow release unit in the scale position. Common misconception with the DG is that it goes in the hole in the nose, but it doesn’t – it sits about one third of the way down the underbelly of the fuse. This is a simple mechanism using an aluminum block with a hole drilled for the spring steel actuator. A slot is cut for the loop to slide in from the underside going through almost half way up the bar… a little past the actuator hole allowing for the clearance of the loop past the actuator rod.
The hole in the front of the DG is where they place instruments and also the air intake for the cabin. For the sake of clean flying I turned up a little recessed ali slug to fill this void.
Before the fitting the aluminum slug, I fitted the canopy hinge. This is made up of two pieces of spring steel and a small piece of brass tube. The canopy hinge bar pivots on the brass tube – all of these need to be a snug fit. The bend in the spring steel needs to be at the angle of the fuselage walls. Once it is right – the whole unit is epoxied in.
A note here: almost all of the areas I used epoxy, I also used a considerable proportion of cotton flock (West Systems 403 microfiber blend). This not only makes the epoxy easier to work with and fillet, it makes the epoxy white which matches better with the rest of the fittings.
Straddling the tow release are the battery packs. – this is the furthest forward the packs can be placed and still not interfere with the canopy tray. Velcro strapping is used to secure the packs to their ply mounting plates. I have used 2 x 4000mah elite sub-c 5 cell packs. I will be running the whole system using 6 volts. (make sure your servos are capable if you are going to use 6v).
The tail
Changing focus to the tail feathers, most of the work here is already done for you. The fin posts are already installed with the mounting for two elevator servos. I did find having two servos here a little odd… and I was not absolutely sure why they opted for two servos driving one surface. But I hoped the idea was for redundancy. With that in mind I chose two JR DS3405 coreless servos, and later will match them using the Smar-Fly unit’s programmable features. Each servo has its own pushrod and control horn on the elevator. One thing to note is that the geometry of this setup requires that you drill a new hole for the clevis so it sits as close to the control surface as is possible without actually interfering with it. Once matched. This system does create an incredibly tight and slop free elevator!
Mounting the elevator is all done, using two mounting screws. The elevator seat needed no work whatsoever and when checked with the incidence meter, was set at exactly 1.5 degrees negative incidence – perfect!
The rudder came with one pre-molded slot for the enclosed pin hinge. I decided to create the lower hinge using a pin that is located at the bottom of the fuse and the rudder slides onto it before sliding in the slot hinge in place and inserting the upper pin. A little carbon reinforcement for the lower pin made all the difference. The rudder mounted this way ends up being very positive and effective.
The rudder uses a closed loop system (also known as pull-pull) for control. The fuselage comes with pre-fitted control tubes mounted to the fuse sides, but I much prefer a nice and tight closed loop system. The servo for the closed loop is mounted on a quarter moon former and using Aluminum right angle for the servo mount. Once fitted just rear of the retract unit – the closed loop lines are secured and servo centered. There is nothing like a good pull-pull for positive rudder coupling!
The Wings
Well – what can I say – Lots of servos!
All of the servos used for the control surfaces are JR ES579 metal geared and ball raced. This means that at 6v they are producing about 8kg per surface…. That should be more than enough! The servos in this instance are mounted wrapped in battery shrink wrap then epoxied to the wing skin. You have plenty of room if you want to use a commercial servo mounts, but I opted for the F3j style servo mounting.
Setting the wing up, the wiring loom is installed first, test servos and throws, then glue in. I made sure that all servos were centered before I installed the horns and all servos are placed in exactly the same position relative to the control horns. The brass control horns and captive threads are very neat, just needing a small amount of clearing with a tap to remove some of the excess epoxy from the threads.
I have used 3mm all thread and clevises for the control rods. Once everything was centered, the threads were locked using cyano. The supplied servo caps were trimmed and installed using white vinyl.
The airbrakes
I used HS85mg’s for the brake actuators but you could always fit larger servos here – there is plenty of room. The only servo that started to get a tight fit was the full size aileron servo. Mounting the brake servos was the same as for the other servos, and a quick soldered brass link and clevis makes the connection. Turning the wing over, the supplied airbrake cap strips were a bit thin, and required a standoff in between to fill the gap between the top of the brake and the flush position of the brake cap strip. I used some PVC sheet with holes drilled every 20mm. this created a very strong bond between the various layers. The cap strips that are supplied have a great finish and are hand sanded to fit the air brake holes prior to fitting. Remember to bevel the edges!
The Brains
With the wings complete all that is left is to complete the loom and install the Smart-Fly system complete with JR receiver. Even with the new JR/DSM RD1221 receiver having dual battery inputs, I always prefer to route the battery power past the receiver for the servos. Using the Smart-Fly PowerExpander EQ10, not only can I do this easily, but I also eliminate any need for any other y leads or servo matchers. The Smart-Fly EQ10 also manages my twin batteries, gives me a digital switch that eliminates the danger of mechanical switches failing and allows up to 4 servos per channel with individual servo programming.
To mount the receiver/ Smart-Fly EQ10 unit (what I call the head unit) I created a small brace to mount it all to the side of the fuselage. With the retract down, the head unit can be removed with four screws if required. The receiver is mounted with the supplied heavy duty mounting Velcro. The unit has one other benefit – because of the way you have to wire it up, it has the flow-on affect of “cleaning” up your wiring installation.
As part of the fit out I also installed a Wstech Classic Sound and Voice vario with total energy compensation (the review of this unit is available here). The unit is mounted on Velcro to allow for quick transfer to other models. But the TEC tube is permanently affixed in each model. The pitot tube is also transferable from one model to another. What I like about the Wstech is that the vario has 4 settings that can be switched in flight from a servo output, and it gives me all the information via voice or sound output. They are just in the process of releasing a CS Data version that also has a GPS module and data logging capability – I look forward to having a look at it when it becomes available.
This short outline on these items just does not cover the power they provide, so I will be covering more on these items in future articles, so stay tuned.
The canopy
Probably one of the harder items to complete on the DG is the canopy. The frame is probably the only item I was not totally happy with. It required some “adjustment” and heat treatment to get it square on the fuselage. There was also a significant amount of sanding required to get the fit of the canopy on the frame just right, and even then it was not perfect – but once it is done it looks impressive given its size.
The gas strut in connection with the hinge works a treat, and later I intend on organizing a better latch system than the daggy “on the top of the fuse” latch that I have currently installed… but it works!
Setting up
The surface throws were set exactly to the settings provided and I needed 630grams of lead to achieve the 105mm CofG. Although after the first few flights, I would say this is a “on the edge” setup and think I will test at 100mm and 95mm respectively. At 105mm, the shallow dive test produced only a very slight recovery… if any and I’d like just a bit more positive nose-up attitude for my style of flying.
Flying
At the time of writing this, I had only clocked up four flights, and most of that was trimming and testing. The last flight I had, I found a nice thermal, hooked into it, stooged round a bit at 500+ meters and then screamed back to 200+ meters… and can I say… this baby knows how to boogie across the sky!
In three words:
I Love it!
It can thermal, it can scream along, and it looks great! What next… well some aeros!
In Conclusion
Well, it is hard to fault the overall kit. I was initially perplexed why the flaps had been introduced into the model when there is no full size variant that carries them... but after landing it a few times, I have grown to appreciate them greatly! As a build kit, it is neat and tidy with everything fitting nicely… except for the canopy frame. Maybe get Paritech to fit that for you?
The finish on the molding is superb and the surfaces are all straight and without bumps.
Flying is a pleasure and in actual fact it is quite docile on the tow and slower flying… till you crank up the speed – then you can have some fun. I was especially impressed in the slow thermaling characteristics and how slow it will actually turn before dropping a tip.
If you are venturing out to buy a fully molded model, then the Paritech DG 303 is not a bad choice given its value for money. If only there were more if this range available in Australia!
Price
€1685 (but you can always add more items pre fitted)
Value for money
7.5/10
Performance
9/10
Experience required building
Moderate - experience required
Experience required flying
Moderate - Good +
Satisfaction factor
9/10
Approximate building time
40 hours (with the changes I made)
In Australia available from:
Kit not available locally - you have to purchase from overseas
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