Magnus 60" Span Moulded Soarer by TJIRC

[Peter Garsden]

 

The kit comes very well packaged and wrapped well for transportation.

 

 

Usually the metal clevises are poor quality and have to be replaced - not here. Also the wood for the servo mounts is good quality ply. Great value for money.

 

I was minded to buy this super fast sloper from T9 Hobbysport after I had seen this model fly at the local slopes and having seen several fly at such incredible speed.

 

It is a 60 inch wingspan all moulded glider with elevator, flaps, and ailerons but no rudder, and really it doesn't need it. It is designed by Jonathan Wells, one of the country's best pilots who flies up at Rushup Edge near Mam Tor in Derbyshire. He is, I think, the country's record holder for DS flying and a very unassuming chap. I have seen several of his designs and they all fly fast. He has done some designing for Doc James Hammond and knows his onions. The whole TJIRC Chinese range is so reasonable in price. I also have their MiniQ which also flies very fast and well.

 

It is only £259.20 which for a moulded soarer is a bargain. Whilst I bought it from T9 Hobbysport, it is also available from Hyperflight. This is the URL for T9 - https://www.t9hobbysport.com/magnus-60inch-moulded-glider

 

It flies in any wind with little ballast but there is space for some ballast in the wing. One can either buy a brass bar or slide in strips of lead. I think I will do the latter.

 

It requires 9mm thick servos for the flaps and 8mm for the ailerons. I have bought a Bluebird servo for the fuselage elevator - an HS65 by Hitec is recommended. For the wings Jonathan also used Bluebird but I have gone for a cheap but reliable meta geared 8mm slim wing servo from 4 Max which I have tested out on my Jart and it seems OK even though it only has about 2kg of torque.

 

I am considering what sort of battery to use in the fuselage presently. I would like to use 6 volts but don't know how I am going to fit in the batteries. I might have to plump for 4.8v but I would like the extra torque for the wing servos.  They are super slim at 8mm but only 1.4kg of torque. Because I have had no trouble with them on the Jart which does fly very fast, I am going to test them out on the Magnus also. They are a quarter the price of KST or Bluebird 8mm servos but about a third of the power. This is the link - https://www.4-max.co.uk/servo-4max-4M-094DMGB-014.html

[Peter Garsden]

The Elevator

 

The first job is to fit the tailplane and install the elevator horn. The tailplane attaches with 2 very small bolts that would be very easy to drop into the grass on site. Also the tailplane is a good tight fit and would probably get scratched if constantly refitted. Finally the bolts are not magnetic so dropping them into holes would involve some Pritt Stick and a good deal of patience, so I think I am going to leave it assembled.

 

 

You can see that there is a ridge left where the 2 fuselage halves have been glued together. To remove the join you need a ball attachment to your Dremmell

 

 

Then mark the position of the elevator horn 2mm from the leading edge of the elevator. You also have to open out the hole for the tailplane carefully with a half round file so it slides in sideways without scratching it but doesn't become too loose - fine dividing line. Don't try to push it in from the rear (how do I know this?) because the skin of the tailplane will be dented due to its shape. The skin is quite thin.

 

 

Difficult to see but the micrometre measures just over 2mm.

 

 

The slot for the horn measures 15 mm long. This must be cut with a 1.5mm router bit. You can see the slot for the control rod is very small so accuracy is important here. You can see the holes for the screws and the issue with locating and tightening them with an appropriate screwdriver and what a fiddle it is on a hill with the wind trying to lift you up and launch you into the blue yonder? I would recommend installing the tailplane before gluing up the horn - ask me how I know this? I didn't and it is slightly askew. I hope it won't bind.

 

 

Again be very careful with the bit that it doesn't puncture the skin on the other side. Again ask me how I know this! You can feel with your finger but if there is masking tape it is difficult to feel. Also don't put the bit vertically as 2 holes can easily appear! Also important to cover the surface with masking tape to protect the finish from dings. Don't ask me how I know this because amazingly I got this right.

 

 

You can see the fillets left after the masking tape is removed. Ideally leave a small uncovered border or remove the tape before you glue.

 

 

I used a mixture of 20 minute epoxy and microfibres. The mystery of what powders to use is a tangled one. Basically adding powder to epoxy makes the mix thicker and fills joins. It also creates fillets to support the horn. Microfibres strengthen the joint as does milled fibreglass powder, whereas microballoons, do not add any strength but are light and easy to sand, so use only as a filler powder. You can also use powdered cotton as a strengthener. The idea is to increase the viscosity to match the material you are trying to glue. Epoxy does not work well with fibreglass because it is more flexible than the material it is trying to join, hence the use of powder. For a full guide go to any of the Fibreglass supplier's sites such as East Coast Fibreglass or Easy Composites.

Edited March 15, 2021 by Peter Garsden

[Peter Garsden]

I usually reinforce the front of the fuselage when it is lacking in strength or is made of only fibreglass. Often there is a lack of carbon reinforcement so as to avoid signal interference unlike under the wings whereas this is just where you need the strength to protect from heavy landings. I try to use Kevlar because strength is added but no signal interference. It is however difficult to cut and trim. I managed to find some thin Kevlar which is also difficult to source.

 

I made a paper template then cut out the cloth.

 

 

 

Again, important to protect the fuselage with masking tap. You can see the carbon ribbon which does help but is not as strong as the full carbon version which is also available by special order from TJIRC. Also rub the inside of the fuselage with Isopropyl Alcohol to remove any manufacturer residue.

Edited March 15, 2021 by Peter Garsden

[Ron Gray]

Looks nice Peter and as you say, good value for money (for a mouldy). Good idea to reinforce the fuse.

[john stones 1 - Moderator]

Looks like being fun. ?

[Peter Garsden]

Fun John is not how I describe putting mouldies together. As we say up North, "Ther a right fiddle." When you are playing with millimetres at times you want to chuck the whole thing out of the window, and I have never understood why they never come with instructions! The more you pay the less help there is. Rant over.

 

For example the tailplane is meant to be fixed in place with tiny screws which screw into threaded holes in the tailplane. They are only just long enough and are bolts rather than screws. You have millimetres of leeway. I found out after fiddling for ages that you have to turn both screws a turn or two to get them going then tighten them both up. I tried putting one screw in at a time tight. This meant that it displaced the other hole and the other bolt wouldn't go in. Anyway it is done now. I wondered why other builders had abandoned the screws and glued in the stab, as they call it in America.

 

I have been considering what battery to use. I would have liked to go high voltage for a change but my cheap wing servos are maxed at 6 volts so no chance of using a Li-ion battery at 7.4 volts. The slim 4.8 volt batteries are out of stock everywhere - the Premium Sport 1600mah type, and no shape of 5 cell pen cell will fit, so I have gone for an AAA long and thin type which is 91mm x 20mm x 10mm. Only 800 mah but it will do.

 

T9 sell a different type of servo tray to further strengthen up the fuselage.

 

 

I have done this before but used 3mm fibreglass rather than plywood which is much stronger. I am going to bond 2 pieces of 1.5mm circuit board together. I have been making a template out of cardboard.

 

[john stones 1 - Moderator]

Ah, I was referring to when it's chucked of a Hill Peter.

[Peter Garsden]

On 16/03/2021 at 13:01, john stones 1 Moderator said:

Ah, I was referring to when it's chucked of a Hill Peter.

 

Ah yes indeed very much so. It flies like the wind. Worth all the frustration and fiddling about, as indeed is true of most mouldies.

[Peter Garsden]

 

The  nice man from Amazon (long way to travel just to deliver a battery?) brought this today. It is shorter than the Li ion alternative but deeper at 20mm, so it doesn't fit quite a far down the nose as I thought. I suspect some Kevlar is fouling it slightly but no matter. I will probably fill the gap with lead. Just depends how much nose weight it needs. This is a light battery, so....

 

 

I have wondered where the Receiver should go. This is the suggested layout. I could put the receiver behind the battery and the servo further back, but I don't think there will be room for the wires to pass beside the servo, so I think the best alternative is behind this plate and under the wing which will be also occupied by the wing joining bar, and there has to be space for the elevator pushrod! See what I mean about fiddling about?

 

I think I will also have to extend the battery wire - then there is the electronic switch? I might cut away more of the rear of the plate so the receiver can slide forwards a little. There is so little room. Wait until we tackle the wings!

[conrad taggart]

Pete really enjoying this build thread.

Did you use a balloon or anything to keep the Kevlar tight to the fuselage ?  

When cutting Kevlar or even carbon cloth I have used this glue to adhere  grease proof paper to it.  When you cut your template out it holds everything together (especially carbon cloth) and makes it considerably easier to cut, whilst  blunting your scissors less.   It makes it easier to wet-out and transfer the cut template to the aircraft, without it going out of shape.   If you attach the paper  to the whole sheet of material it also makes subsequent  storage easier and when you need to cut the material again - it is good to go 

 

https://www.amazon.co.uk/gp/product/B002BB9A4S/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

Edited March 18, 2021 by conrad taggart

[Peter Garsden]

Hi Conrad, not seen you for ages.

 

No I didn't use a balloon but probably should have done. Gravity held it down. Whenever I have tried to use a balloon before they have always burst. I have some long balloons but I can't generate enough puff to inflate them - probably my age!

 

Thanks for the tip about glue and paper. Will have to look into that.

[Peter Garsden]

Just followed the link - am familiar with this and have a can of it. I used it to adhere cloth to lost foam moulds on top of parcel tape. Good stuff.

[conrad taggart]

21 hours ago, Peter Garsden said:

Hi Conrad, not seen you for ages.

 

No I didn't use a balloon but probably should have done. Gravity held it down. Whenever I have tried to use a balloon before they have always burst. I have some long balloons but I can't generate enough puff to inflate them - probably my age!

 

Thanks for the tip about glue and paper. Will have to look into that.

Pete rE the age thing - try these https://www.amazon.co.uk/SOL-Balloon-Multi-Fit-Nozzle-Canister/dp/B085CF8CGM/ref=sr_1_1_sspa?dchild=1&keywords=party+balloon+pump&qid=1616178319&sr=8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEzUFhHRVlUMExYWFpTJmVuY3J5cHRlZElkPUEwNDI3Mzg1QVgyRUlOMzlCQktUJmVuY3J5cHRlZEFkSWQ9QTA1NjU1ODRRUlZSUTZGVThZSjkmd2lkZ2V0TmFtZT1zcF9hdGYmYWN0aW9uPWNsaWNrUmVkaXJlY3QmZG9Ob3RMb2dDbGljaz10cnVl

How thin is your Kevlar and where did you manage to source it from - like you most of the stuff I have seen is fairly thick and hence is a bit difficult to get it to really adhere consistently? 

 

Thanks

Conrad 

[Peter Garsden]

To be honest I can't remember where I sourced the Kevlar Conrad.  It was ages ago. I have looked since and can't find it again. Sorry. 

[Peter Garsden]

I have indulged in more blade blunting - this time the Dremmel Fret Saw - I drew round the cardboard templates onto the 1.5mm fibreglass circuit board and tried to cut it out with the Dremmel Fret Saw. It dulled one blade and I think the next one is going the same way. This meant that it was difficult to do an accurate cut on the second blank. No matter, when the 2 are glued together and the dodgy one underneath it will be find and will fulfil the purpose which is to strengthen the fuselage.

 

 

You can see that I have roughed up the surfaces to be glued. 

 

Also I have decided to stuff the receiver behind the plate. Hopefully it will not bind the elevator control rod as I think there will be a surfeit of wire. I have made up the Multiplex plug and wire for the fuselage by way of experiment. If necessary we can cut back this tray nearer to the elevator servo to make more space.

[Peter Garsden]

I glued the 2 pieces of circuit board together with epoxy then filed them so that they were identical and would fit into the fuselage. I then roughed up the gluing surfaces with a ball attachment to the Dremmel.

 

 

The finished servo tray is now 3mm and shown here. I then mixed up some 20 minute epoxy and milled fibres and spread on both surfaces before gluing into the fuselage. I inserted the elevator servo to make sure it was the right height from the bottom of the fuselage.

 

 

I used one of the thin coffee stirrers from Costa to make a fillet in the gap.

 

 

Before the glue had set, I sighted down the fuselage to make sure the carbon rod elevator linkage would not foul the bottom of the wing joiner. It is miles away. Issue - how to attach the servo to the tray. Will it be possible to use a screw - or should I thread a hole and use a bolt? I think the latter.

 

 

 

[Peter Garsden]

 

Just thought I would show how I cut carbon tube - this is 4mm outer and 2mm inner. I use this abrasive disc. The masking tapes stops the tube splitting into strands. Careful not to touch the sides of the fuselage. The horn is attached to the elevator and is a fiddle to remove so cut this in situ. The studding is only 26mm long so half - 13mm gets glued into the tube. When making my own, I usually have longer pieces of studding with more protruding so care is needed here.

 

 

This shows the finished rod with the clevis attached - but not the cheap ones supplied with the kit. I was tugging at the supplied clevis which came off the tail even though it was properly attached. I thought it was slightly loose but didn't think it would slide off which it did. These cheap clevises always seem to be supplied with mouldies. They are not fit for purpose. I am sure it is price but better to omit IMHO as then it makes you source good quality Multiplex items. Obviously buy the 2mm type which fit the studding.

[Peter Garsden]

As usual with mouldies we are in a chicken and egg situation in that before we can install the plug and sockets for the flaps and ailerons to the Receiver, we have to solder up the wing half of the leads (the 2 Multiplex plugs must be connected when applying the solder so as to avoid melting the socket and loosening the leads). We cannot do that until the wing servos are installed and connected...so to the wing next.

 

I also forgot to say that the holes for the elevator servo bolts must be tapped to take bolts because screws won't work in fibreglass. Fortunately I have recently bought a 2mm tap and die set.

 

 

The Flaps - the horn should be 10mm from the edge of the servo recess, so we apply tape to protect the surface and draw a line.

 

 

Transfer the line to the top of the wing and mark 6mm from the wiper. Cut out a hole for cutting outline the horn.

Edited March 26, 2021 by Peter Garsden

[Peter Garsden]

 

Usefully, the horn supplied slides into the flap, not to be glued yet but abraded in readiness and wiped with Isopropyl Alcohol. One must dremmel through the wiper and innards of the flap down to the top skin but not through. I used the 1.5mm tool used above on the elevator.

 

 

This shows the cutting marks for the clevis. I am not going to glue the horn in position until I can get the right angle for the rod to meet the servo horn - often a problem

 

 

This shows the Dremmel tools I used for the larger and smaller holes. I bought a very cheap Dremmel (not that name) which came with a large variety of tools. I don't use the driver whose motor was too weak but the tools come in handy. The larger tool is a grinding tool for sculpting I think but it grinds the fibreglass nicely.

 

I think that the combined lengths of 2 clevis is too long for the distance required so I think I might use the bent and tapped rod idea of Jonathan Wells.

 

[Peter Garsden]

Ailerons

 

Similar process to the Flaps only the line for the horn is 13mm instead of 10mm from the outer line of the servo recess ie

 

 

One then transfers the line to the top of the wing

 

 

Then mark the cut for the horn to be inserted on top of the wing 6mm from the leading edge of the Aileron. Cut through the wiper using the 1.5mm Dremmel shown earlier to make a hole for the point of the horn to fit under.

 

 

Then mark a slot 17mm from the trailing edge of the wing 4mm wide for the clevis to travel down and cut away the balsa making up the trailing edge of the wing to leave a hole for the metal clevis to pass down. File away if necessary to make it fit easily.

 

 

Incidentally I have decided to put Bluebird 125WV meatier servos in the wing for flaps (4KG of torque as against 1.7kg) and just use the cheap 8mm 4 Max servos for the ailerons as 10mm just won't fit.

[Peter Garsden]

I had a panic when I found that my threaded rod slipped through the clevis hole without gripping, until I realised that this is a 3mm clevis. I had trouble getting it off the horn but managed it. I won't be DS'ing this one so don't need 10mm servos and 3mm rods etc.

 

 

Difficult to see but I glued in the horn with the clevis attached so as to get the right angle. There is so little margin for error. I debated whether to glue everything at once ie the servo but it would be impossible to hold everything in position at once. Again I used 20 minute epoxy and microfibres. I did both Aileron and Flap horns at the same time.

 

 

Next comes making the connecting rods, and gluing in the servos

 

 

You can just about see that I had a go at the bent rod attachment to the servo with the end threaded. I ummed and awed about this and decided to do things in the following order - don't know if this is right

1. Put the servo in place and measure for length. I marked the bend on the wire.
2. Cut the wire 7mm from the bend.
3. Tap the end of the wire down to the bend.
4. Heat up the wire to help with the bend to red hot on the gas cooker holding the wire with pliers.
5. Bend the wire in the vice to a right angle.
6. Screw into the clevis to line up with the hole in the servo horn which has been drilled and tapped - I used the drill that came with the tap as I found my 1.6mm drill too big. I had to scrap one horn. Obviously the hole has to be drilled as close to the servo pivot as possible.

I have shown the Permagrit tool I used to rough up the surface of the carbon to hold my laminating resin glue.

 

 

This is the 4 Max 8mm servo used for the aileron. The servo is glued to both upper and lower wing skins for extra rigidity. MAKE SURE you thread your wires for both flap and aileron servos down the wing before you glue in the servo particularly because the aileron wire has to thread round the Flap servo, the ballast tube, and the wing spar. Impossible after the servo has been glued into place.

 

 

Because there is so little room, I am going to solder the wires together rather than use plugs.

 

 

This is the stuff I use to glue in the servos. Reason is that it dries more brittle than epoxy glue and makes it much easier to get them out again if necessary. You just put a screwdriver under the edge and leaver it out. As it says on the packet, you have to wait 3 hours for it to cure.

[Peter Garsden]

Servos in, so next is attaching the Multiplex plug and socket. The male plug goes in the wing and the female in the fuselage attached with super glue.

 

The Male will be left loose so it will be constantly pulled in and out of the wing to attach it. Hence the joints have to be made solid. I have always covered the plugs with hot glue to give it rigidity. There is not much space, however, so no overlap. Some filing to make it fit has to be done anyway.

 

 

I do all the soldering with the 2 plugs attached. This way the heat does not melt the plastic and make the pins loose.

 

One can see above how I have sealed the plug wires in place with hot glue. I do this by putting the plug on the edge of the Aluminium plate and squeeze hot glue onto it. I then place the brass plate - I have lost the other Aluminium sheet I used to have. This squashes down the glue and attaches it to the wires and the plug. I then turn it over and do the same on the other side. If necessary I trim the sides with the snips.

 

I then wrap the wire behind the plug with insulation tape. Otherwise a weak point is created where the hot glue plug ends.

Edited April 6, 2021 by Peter Garsden

[GrumpyGnome]

LOTS of work in that mouldie - naively I thought you threw some radio into the box, shook it, and out popped a glider, all ready to scream around the slope!

How wrong I was.

 

GG

[Peter Garsden]

The servos are now in the other wing and the covers on. The leads have been put in the fuselage and the plugs connected and the receiver installed. All surfaces work and the settings as recommended by Jonathan Wells who has done a very handy chart

 

 

I have thus rigged up my Vanessa C of G Machine with the C of G at 79.5mm as I am not a beginner and can cope with this sort of position. I hope it will fly as fast as other models I have seen flying at Leek. The plumb bob balanced at this mark with an extra 80 grams of lead in the nose. I am going to make a plasticine plug then melt some lead into sand then epoxy it into the nose. I have to be careful to not make it too deep and foul the battery.

 

[john stones 1 - Moderator]

Very nice Peter.