Miraj Review by Andrew Freeman

Iíve fancied a relatively large performance sailplane for a while but have been generally put off by the thought of having a hollow moulded job and putting a ding in it, or worse. Having flown Philís Aldij and been impressed by the performance, agility, docileness (no nasty surprises) and also the ding-proof nature which all the Aeromod range possess, I decided to order its slightly bigger brother, the Miraj. There isnít a huge difference between the two visually: the Miraj has the faster MG06 wing section and is a foot bigger in span (2.5m/ 8ft). It is also multi-tapered giving it a unique appearance.

So what do you get for your hard-earned cash?
A fuselage with the characteristic Aeromod mould line and tailplane joiners pre-installed; a centre wing panels and two outboard panels (at last I have a model that that will fit entirely into the boot of my Fiesta!) with control surfaces pre-cut for you (one of the main reasons for ordering it over the Aldij); two tailplanes, also with surfaces pre-cut; a ply servo tray; four solid 8mm carbon rods; two ∆ 6mm x 1500mm carbon push-rods (far more than you need!); some ball link fittings; some captive nuts and bolts; some carbon roving; and finally the instructions.....which were in English much to my relief! The instructions, although appear to be a direct translation (they are from America, so they could be in American "English" I suppose: we know they canít spell afterall...) are very good and donít leave any second-guessing. Well, not much anyway. One grumble about it is it would have been nice to finish the rest of the kit off like the American version where it comes with everything apart from the radio gear, glue and silicone. Itís a bit annoying to go and have to buy a load of bits, particularly when the model shops closest to us donít stock the bits you want. Mentioning no names, but two of them didnít even have any epoxy! (well, actually thatís a lie, they did offer me some tubes of Araldite.....). So off went a shopping list to Stan Yeo of Phoenix Models and two days later appeared a package containing everything I needed to complete the job.

So what do you have to do before you can play with your new toy?
The Aeromod range requires more work to be done compared with the fully moulded Eastern Europe jobs: they are more a case of bunging in the radio gear and flying. Here you have to spend a bit more time building it and fiddling around. They say you should be able to finish one off in 12 hours, which seems quite reasonable, but I spent at least 40 hours Iím sure. From hindsight I reckon thatís its possible if you know what you are doing, i.e. youíve built one before, and you have the workspace to do it in so you can carry on doing one thing whilst the glue is drying on something else for example. I decided to take my time on it and do one thing at a time, working on the principle that itís easier to sort out one cock-up at a time rather than have several to sort out all at once.

John Bennett's MiriJ at Selsley

 As it turned out no cock-ups emerged, which was nice, thereís a first time for everything I suppose.

I wonít give a blow by blow account, but will highlight useful bits I have found and areas of the instructions which I...err.. ignored.

The instructions began with assembling the wings, so thatís where I started too. With the control surfaces cut for you, all you have to do is dig out some foam from the leading edge of the control surface. A small flat bladed screwdriver is good, just keep the "digs" small and donít tear too much out at once. You fill this hole with a 50:50 mixture (by volume) of epoxy and microballoons. This ties the skins together and increases the torsional stiffness of the control surface considerably. Remember to mask the control surface to prevent epoxy overspill from spoiling the finish. Hint: if you do get some epoxy where it shouldnít be, WD40 makes a great epoxy remover. Simply spray some on a cloth and rub: itíll soon dissolve it. If you need to remove the traces of WD40 for whatever reason, washing up liquid will take that off.

Now, the instructions will have you silicone hinging the wing and then installing control horns, however I didnít like the control horns supplied. These are brass M2 ball links, which in my opinion are far too weak for the job. There was also the added problem of length. The instructions say mount the link so the centreline of the ball is 15mm from the skin. A bit difficult to do when the link is only 15mm long itself! I decided to opt for some decent brass adjustable control horns from Gliders Distribution. These are epoxied in place when microballooning the leading edge.

You also have to dig the foam out of the trailing edge of the wing so the control surface can tuck inside it when it moves down (see below). This is has the same effect as a wiper closing the gap up, but nowhere near as efficient Iím sure. I "painted" a very thin layer of epoxy on the foam just to prevent it from pulling out over time and also to aid the silicone in adhering when I did the hinges.

The silicone hinging process is quite straight forward, when you know what you are doing.....my advice is practice it first! Hint: if you cock up the hinge, I have found it far easier and cleaner to remove when it has dried for about two hours (in its rubbery "green" state) than trying to wipe it off wet.

First thing to do is to ensure everything is clean so the silicone can get a good key.

Next is to temporarily tape the control surface to the wing using sellotape and set a hinge gap. I set a hinge gap of 0.8mm for the wing, and 0.6mm for the elevator. Make sure the control surface can move down adequately without binding.

You are now ready to hinge. Select a good grade silicone, preferably the stuff used to make/ repair fish tanks with. This is available from most good aquatic centres. I got mine from "World of Water" at the garden centre at the top of Whitminster hill. It is relatively expensive (£4 a tube), but then remember so is another model, and it is good stuff anyway.
Fold the control surface back on itself and run a thin bead of silicone all the way down the hinge line. I used about 2mm bead for the wing and 1mm for the elevator. Hint: it is difficult to control the flow of the silicone in the dispenser it comes with. I fill up a syringe instead, which makes control of the flow easier, and it is also easier to hold. You get a much better hinge line from it. You then gently run a wetted finger over the silicone to force it in the gap and get a good key. Fold the control surface back so it is in its neutral position and leave to set for at least 24 hours. Remove the tape, and hey presto, a good strong hinge. Just try to pull the control surface off, you canít do it!
You are now ready to install some servos. The wing is mounted on a pylon, as opposed to the usual shoulder mount, enabling it to have a single central flap and two ailerons. The central flap is driven by a Hitec HS225MG mounted on a servo tray in the fuz and the ailerons are driven by a pair of Hitec HS85MGs mounted on the outboard part of the centre panel, removing the need to have another connector to do up when assembling the wings
Lots of foam digging is required to put the servos in, mainly because the hole intended for the servo wire isnít big enough to get a connector down! You also have to dig a hole for the servo to sit into. Luckily the foam isnít the usual white type which we make our wings from: it doesnít have the electrostatic properties of its relation, which is great because you donít end up looking like Frosty the Snowman after a foam digging session, of which there is lots with this model!
 It is however a complete pain in the arse to dig it because it is sooo tough its unbelievable. Just take your time and remove bit by bit. 
Now the manufacturers would have you cutting a T-slot in the outboard panels so the control horn of the servo can pass through. Quite why I donít know: you end up leaving two thin pieces of skin that are eventually going to break off
My solution is as follows: Cut an ordinary slot in the panel

. . When you want to put the panel on, turn the servo horn so it doesnít protrude above the skin, slide on the panel, power up the model and the servo will return to itís normal position so you can connect up the pushrods. To take the panel off, simply push the horn back in below the skin and you can slide the panel off again. Simple. (see pictures).

Mounting the wing is easy enough to do, but a spare pair of hands is always a bonus. The drill holes are marked on the wing so it is simply a case of drilling through, starting off with a small pilot hole. I drilled the holes so the screws were a tight fit, preventing the wing from rotating in the holes during assembly so it goes on straight. Lining the wing up on the fuz, I then drilled over size holes through the wing seat, so the captive nuts (mounted on individual ply plates) could initially "float" in the holes for allowing me to line up the wing. Using Ĺ hour epoxy, the plates were glued in place, but before the glue set, the wing was bolted on and the distance from wingtip to tail and wing tip to nose measured to ensure the distances were equal. It was simply a case of rotating the wing until they were (hence the need for the float) and then leaving the glue to set overnight, making sure it couldnít move. I put insulation tape between the wing and seat to prevent the panel and fuz becoming a one-piece item during this stage. I replaced the slotted head screws that came with the kit with countersunk socket screws: this way a slipped screwdriver wonít damage your nice paintwork.

The stabilisers slide onto two carbon tubes that are pre-fitted in the fuz. The problem with carbon tubes is that they can be brittle: once they start to crack you canít stop them. To make them solid and hence far more tough and resistant to dodgy landings, here is a simple tip. Take some carbon tows and double/treble/ etc them up so they just about slide into the tube. Pass a thin piece of string through the tubes and tie the carbon tows to it. Wick slow setting epoxy into the tows and slowly pull them through: they may jam so take it carefully and try not to pull the string off or snap the string etc. Once the epoxy has gone rubbery, you can take a sharp knife and cut the excess tows off.

All thatís left really is to make up a servo tray and pushrods (using the carbon tube provided) for the elevators, ailerons and flap. This is relatively straight forward so I wonít go into any detail, except that instead of epoxying the servos to the tray as suggested in the instructions, I spent a few more minutes making up some rails for the servos to be screwed on. You never know when you might have to replace a servo, and a few minutes spent here saves a lot of aggro later on.

First test flight was off Frocester on a relatively calm day. The wind strength was perfect for test flying a new model: not so strong you were left wondering whether itíll get blown off course before youíve even touched the trims, and not so weak that you were left thinking that youíd be collecting it from the field below after youíve chucked it off. After a quick test flight with a Zagi to find out what the lift was like (with much heckling from Phil, Wolfie and Rich Hobson) she was launched off the slope and......nothing. 
It was the first time Iíd launched a model and hadnít been scrabbling for the trims. A touch of up was required to correct the glide path, but then it was nose heavy for the first flight. Switching in the thermal flap, the response was good: the model climbed steadily with no input from me. With a bit of height gained some relatively slow passes along the slope were made showing good control response. Some simple aerobatics were attempted (e.g. rolls and loops) which it performed with ease. This model really does inspire confidence from the start, it is so easy to fly it just goes where you tell it, and it wasnít even fully trimmed out! Within 10 minutes, the inverted performance was put under test and despite the light lift, it performed a circuit without any problems, needing very little down to keep the nose up. Time to gain height for a speed run: the flap was dialled in and some height gained. 
Switch to reflex and a dive across the slope showed quick acceleration and a good turn of speed. Bang in full aileron, and sheíll roll in half a second, not bad for an 8ft model with only two ailerons and no coupled flaps! Snap flap is very effective: sheíll nearly turn on her own length gripping all the way through the turn. The remainder of the flight was spent familiarising myself with the model and itís characteristics. 
One conclusion is that it needs ballast, even in relatively light conditions. Despite tipping the scales at 2 kg (4.41 lb.) it does appear to fly "light" and needs something to give it that extra punch to help with manoeuvres and maintain speed. Itís supposed to weigh in somewhere between 1.6 & 1.7 kg so I donít know where I went wrong: Iíve seen reviews where the weight is 1.85 kg and F3X.com suggest it weighs in at 67oz or 1.9 kg so Iím guessing there is some inconsistency during manufacture. I would suggest the foam has something to do with it. 

As the lift started to decay, landing was called for. Landing is extremely easy: the crow braking really slows the model down and you still have full control and you can just put it where you want. It was apparent that the speed range is quite impressive, suggesting the model will float around on a light lift day with a bit of camber wound in. 

I found out on Selsley a week or two later how well it would perform in light lift as there was barely enough to get the kites up. With the flaps dialled in to the suggested rates and a hard launch, it went into a steady climb with no hesitancy to climb out. I was surprised: effectively it was half ballasted (the Miraj can carry 700g of lead) and yet it didnít seem to care (someone forgot to tell it there was no lift?!) I was expecting to have to go for a long walk but it never happened. I would love to see the 1.6 kg version go in light lift and I really canít wait till summer when I can hook it into a decent thermal on a relaxing summer evenings soaring (followed by a bit of high octane adrenaline fun during the way down!). 

Each weekend I have been moving the C of G back a bit further towards the specified rear position. So far it appears to have improved the inverted performance (I barely have to put any down in), the model appears faster (it really does chew up the sky, even without any ballast), turns tighter and the aerobatics performance has improved no end. It bunts with ease and will do multiple cross wind square loops with no trouble so now I have no excuse for improving my aerobatics! So far there has been no sign of the nasty flick either, something which is attributable to v-tail models with a rear-ward C of G.


Would I recommend it? To anyone who like me wants a tough, large-ish, very aerobatic, high performance model that will just about fly in any wind strength from a light puff to a gale, is easy to fly (given enough experience of course!), doesnít mind spending the extra time constructing it, I can heartily recommend it. It is going to be a firm favourite for a long time and should anything happen (touch wood) Iíd certainly buy another.


So what next? Apart from using it for performance sloping, I am tempted to race it. Afterall, that is what it is for so watch this space. It is certainly a good model for getting into F3F racing.

page by Phil