SHADOW F3J Review.   by Kevin Beale

After flying Nan models Experience Pro’s for several years, I was looking for another model to replace my oldest one. I am very happy with the Experience Pro and another one was still on the short list. But time moves on and with several new models on the market now  I wanted to check out all options. I have been to several F3J comps around Europe which gave me a chance to have a look at and see how most of these models fly in the hands of some of  top pilots. After much deliberation and having flown a friend’s Shadow V tail many times at our club field, it was clear that the Shadow had the edge in glide performance and despite its 3.7 meter span it was very manoeuvrable. I plumped for the known entity of a Shadow.

The Shadow is another model in the Nan Model range and is distributed in the UK by Acemodel. I have always preferred a conventional cross tail model and the Shadow comes in both V and cross versions. A couple of e-mails to Austin at Acemodel got my Shadow on order. Acemodel have an excellent web site which allows you to select the model you want with a colour scheme from a large range of colours. They also stock a selection of models if you don't want to wait about six weeks to have one made in your prefered colours. I also discussed with Austin about having my own design scheme made for me, which he kindly arranged. They can also supply all the items you will need to complete the model from radio gear to ballast weights.

The model arrived in about six weeks and Austin kindly delivered it to one of the F3J league events for me. At home after sitting back and admiring the quality finish of all the components and checking that all was present and correct, I first checked the fit of everything. The fuselage has a pre-fitted tail plane crank with pushrods installed together with a ballast tube. The rudder pushrod inner should be carefully removed and wiped over with a cloth to remove any mill residue from the outside of the hypodermic tube. Be very careful not to bend the tube. The elevator pushrod inner is solid and does not seem to suffer from the same muck, it can’t be removed anyway.

At the rear end on my cross tail version I checked the fit of the all moving tail plane on to the pre installed control crank. As with both of my Experience pro models this is very tight and required just a little tickling of the control pin hole in the aft direction. You have to be very careful here as the hole is the correct size for the pin; it just requires being made a fraction of a millimetre longer into a slot. I have found the best way to do this is to pull a 2mm threaded rod through the hole with a little rear pressure. Do this 3 or 4 time and check the fit of the tail plane halves. Do not attack the hole with a file as you will end up with slop in the linkage, not good on a fast winch launch. When you are happy with the tail plane fit, centralise the 2 mm control pin so that it is installed into one tail plane half and when fitted to the control crank an equal amount is protruding for the other half. Now with a couple of drops of cyno glue the pin into one tail plane half. This is not completely necessary but if you are a bit clumsy you can push the pin right into the tail plane, causing much grief.

Now check the fit of the centre wing panel onto the fuselage. Mine was perfect and I have never known a problem here but it is worth checking. Try each tip onto the centre panel. I offer my panels up without the main joiner first to be sure that the small incidence pegs line up with the holes in the centre panels. Now fit the tip with the joiner in place, mine was just a little tight as the tips got to about 10 mm apart. Remove the joiners and run a flat fine file one stroke down each edge. In engineering terms on metal we are deburing each edge. This should be all that is required to get a good fit of each tip.

Now for the only bit of building that is required. The servo tray and end stop for the ballast is made from 6 mm ply. Make a card template for each component, carefully trimming each template until they are a good fit in the fuselage. The height of the tray is determined by positioning the servo arm in line with the fitted pushrods, there is a fair bit of flexibility here but the straighter the better. The servos in my installation are at an angle but if you are careful you should be able to get them side by side, just try different arrangements with different card templates to suit your servos. When you are happy with the templates transfer to 6mm ply, cut them out and trial fit them into the fuselage. You will have to do a bit of sanding of the edges to get them in and check that you have sufficient room under the servos for the wiring loom to pass underneath. With a felt pen mark the position of the pieces so you can reposition them easily when gluing. Before gluing them in rough up the glue area with some 80 grit paper and the bit most people forget wipe over with a solvent to take the dust away, I use lighter fuel. Use 30 minute or longer epoxy and you should end up with a solid servo platform.

While we have the epoxy out of the box, make the hatch holding wire from 1.6mm wire (16swg). It has a slight bend in it to follow the centre part of the hatch. Rough up the hatch surface and wire, clean and with micro balloons mixed in the epoxy glue in the wire in two or three places. Ensure you leave enough room for the hatch to move back for fitting and removal.

At the back end again we have to fit the rudder horn. Here is the only area I have a little concern with. There is a moulded-in recess in the fin for the supplied horn and a fairing on the fuselage for the clevis. If you fit the supplied horn by drilling through the fin the flange is too big for the recess. No real problem except that when the clevis is soldered to the pushrod it will not fit the horn because it fouls the fairing. If you grind the flange down in diameter to fit the recess the clevis then fouls the fin with right rudder. My solution was to remove some of the fairing and some of the rudder forward face. Fit the supplier horn with the standard flange just cut down the threaded part to suit and sufficient movement was possible without fouling. It’s up to you whether you want a longer horn for positive position of the rudder or shorter horn fitted inside the fairing.

While on the subject of soldering the clevis to the pushrod you will need a good powerful soldering iron, at least 75watts, or a mini blow torch. If you clean the pushrod thoroughly and use “Bakers fluid” flux a good strong joint is achieved.

The very neat tow hook is the next part to fit. I positioned my tow hook so that with a 101mm centre of gravity from the L.E. the hook towing face was a couple of millimetres in front of the C of G. This puts the forward mounting hole at 500mm from the nose of the model. Drill a 3 mm hole for this fixing and, with the hook assembly in bits, place the mounting part over this hole and drop a 3mm screw through to locate it. Now carefully make the rear fixing hole position and the slot for the hook. With the plate removed drill the hole for the fixing and slot for the hook. The slot can be cut in many ways but I prefer to drill a 4 mm hole at each end and with a thin cutting disk in the drill slit down each side of the slot. Finally gently countersink the fixing holes a small amount and tidy up the slot before installing the hook from the inside.

Now install the fuselage wire harness. This I make but Acemodel can supply these if required together with the wing harness. Just a little tickling of the hole for the dee type connector is all that is required and a couple small screws to hold it in place. With the servos set at neutral cut the pushrod outers back to allow for pushrod travel, take care not to cut the inner. I use a threaded adjuster on this end of the rods soldered to the pushrods. To get the correct length of the elevator pushrod set the tail plane centrally in the control slot in the fin. Once the linkage is in place and connected to the servos the outers have to be glued to the fuselage sides near the hatch, it will require a small packing piece of balsa for a good joint with epoxy.

On to the wings now and very little work is required here. The supplied horns are fitted to the ailerons and flaps. They will need to be shortened a little to get them to a good length for control movement. I try to get mine screwed in so that a 1.6mm wire can be just pushed through the hole with out touching the wing skin with the control set at neutral. The upper wing skin will have to be slotted a little to clear the clevis as will the control surface fairing locally to the horn. The aileron and flap spar is made of 3mm balsa and will have to have a slot in it to clear the control pushrod, this slot will have to go from the top to the bottom wing skin and be about 3mm wide. Your servos have to be fitted next. I have found that the best method is to use the moulded servo mounts that are available from Acemodel. They are made for most of the popular wing servos and after roughing up the mount and wing inner surface are simply glued in with 30 minute epoxy. A tip here is to wipe Vaseline over the servo and glue in the mount with the servo fitted. This ensures that the servo will fit later and you can line up the pushrod with the servo, the Vaseline will not stick to epoxy.

Fit your wire harness into the wing and with the servos set at neutral connect up the control linkages. Adjust them to be as close to neutral as possible. I have the flap servo horn slanted forward to get a good throw for the crow braking, the aileron servo is vertical. When happy it is time to fit the servo covers. Put masking tape on the wing in line with the hatch edge on all four sides, with the bulge in the cover over the servo horn use the masking tape to mark the cover. Cut with good scissors and round the corners before taping in place with clear tape.

I will not advise control throws here as we all have our proffered settings but a few advisory notes may help you on the way. In normal flight mode use at least 50% differential on the ailerons. The flaps should move with the ailerons at about one third the travel of the ailerons. The elevator is quite responsive and 10mm up and down is plenty. For launch I have no coupling of ailerons and flaps and the ailerons have no down movement. The flat settings for normal flight are very small, 2.5mm down at the root for thermal and 1.5 up for travelling. The flaps deflection is across the entire wing. For launch about 10mm on the flaps works well. All these are by no means definitive and will require adjusting to suit you. Again I set my C of G at a pretty safe place to start with at 101mm from the root L.E. This can be adjusted to suit your style but mine is still at 101.

Flying

I hate articles that used to appear saying that the glider flew straight from the box and I did a 1hr first flight. It is at best unlikely and at worst complete toss. However I can say that the Shadow proved its pedigree at its first weekend session.

I was up early on Friday before Interglide, the UK round of the F3J euro league, cutting and fitting the servo covers to the wings before setting off to meet Colin and off to Marsh Gibbon. The plan was to get an afternoon test flying the Shadow before the comp started on Saturday. At the field all checks carried out and range checks done I was ready for a hand launch. A climb to 4 meters and a glide of some 120 meters, a little up trim was needed and I felt the rudder and ailerons for responsiveness. I was pretty happy with that so after checking the position of the tow hook again we put it on the winch. A longer than competition time on the winch to get the feel and watch the gentle bend in the wing before pinging off to a straight high climb. Another click or two of up trim and we floated straight as a die into wind. Checked the turn response left and right with and without flaps, all very smooth and easy to keep the nose up. While I still had some height I tried a dive test to gauge if the C of G was about right for me. All seem good and I brought the Shadow down for a landing on the spot. Feeling quite chuffed with the successes of the first flight and after a couple of tweaks to the control throws we had a couple more launches to get the feel of the Shadow. I was completely at ease with the Shadow after only 4 flights I decided to use it in the two day comp and see how it went. Well reaching the fly-off and getting 4th place was well beyond what anyone would have expected and I can safely say this is the nicest thermal glider I have ever flown. It inspires total confidence from the first flight, it does exactly what you want it to do when you want to and I even got away in the fly-off from 2m altitude. A true thoroughbred.

If you are looking for a large thermal glider for competition, sport or indeed a cross country slope model then the Shadow has to be high on your list. It does everything very well and looks great. Spares are easy to get hold of and lots of information is available on the Acemodel web site. 10 out of 10.

After only half a season with the Shadow I managed to make the Fly Off at Interglide F3J Eurotour 2008 achieving 4th place. 

Kevin Beale.