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Galaxy Models Mystic or Phoenix for a Laser 155.


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I would be tempted to position the servos at the back end of the fuselage rather than using long snakes as per the plan. With the extra weight of the Laser Vs a smaller 2 Stroke that wouldn't be a bad idea anyway.

There's a fair bit of heft in it which could probably be lost if you care, but it does make for a nicely robust and chunky machine.

CG on the plan looks very far forward but is actually ok. Could go back a fair bit I suspect, but I didn't bother.

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The 155 is pretty economical. I use 12oz tanks and get 10 mins takeoff to touchdown with a few minutes reserve. If you use our new low oil fuel economy is considerably improved beyond that so no need to go mad on tank size unless you want half hour flight times.

For servos, standard 3kg jobs would do but an upgrade to 4-6kg would not be outrageous. Savox 351 would be a nice value option. I have a few of these in my 80 inch warbirds and they work well. Savox 352 would also work nicely if you want to really go for it.

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Posted by Nigel R on 31/01/2021 15:50:42:

"Galaxy mystic multi mashup 2021? How many variations can we make? Who will be brave and fit a 3rd engine at the front?

It could be hilarious."

Jon, don't tempt me, I have a biplane to get finishing!

sorry, i just have all these ideas!

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Thank you for your advice gentlemen.

I have found out that 12ozs is about 355cc. Scrabbling about in my tank collection revealed a tank marked "420cc" probably from some long defunct ARTF. It appears to be sound and it should be suitable for what I need.

Miss Blue Eyes has approved the purchase providing that I finish it in white with pink and purple stripes on the wing similar to that of a WOT 4 Extreme. She has this thing about purple and pink. Must be a girly thing!

I will probably stick with Hitec servos as I've always had such good service from them in the past though Savox enjoy an enviable reputation too.

Getting quite excited about the project!

Edited By David Davis on 01/02/2021 09:34:34

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Hi David, completed my Mystic last year but only managed limited flying due to you know what 😨 it is a great model to fly and is one of my favourites . My set up is ASP 120 FS, std size Towerpro metal gear digital servos, closed loop rudder and elevator servo at the back (got a thing about snakes) with the sheeted tail I used a 6v subC pack up front to get the CG right but that will depend on the engine used. The Mystic has been around for many years and the kit has not changed a great deal over the years, some of the parts will need a little fettling to get a good fit but nothing to worry about. I ordered the GF cowl optional extra but I could have glass clothed inside the standard kit one to be honest. If you want to fit the supplied spats work out how you want to fit them to the UC wire before you fit them, I am not keen on spats so I did not bother. No idea what size fuel tank I used just found the largest I had and loaded it behind F1 there is enough room to fit a bucket in there 😂. Waiting to be let loose again so I can get some more flight on the Mystic fingers crossed it won't be long now 👍

Paul

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  • 3 weeks later...

Just a little aside gentlemen.

When I ordered the Mystic there were four in stock. Now there are none! I must have started something!

I will start work on it once a few other aeromodelling and non-aeromodelling projects have been completed. The most pressing matter now is putting in a claim for damage caused by the LiPo fire.

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  • 6 months later...

I have just started building the Mystic and have got to the stage where I have glued the plywood doublers to the fuselage sides. I agree with Paul C that some of the parts needed a little fettling and will expand on this later on but I have a couple of questions I'd like answered before I continue.

 

  1. Thrustline. I will be fitting a Laser 155 inverted bolted to a motor mount. Should I mount the engine so that its crankshaft is in line with the upper fuselage longerons or at least as close as possible to that position?
  2. Is the supplied single wire undercarriage going to be man enough for the job bearing in mind that the model was originally designed for a 61 two stroke and I will be fitting a much bigger and heavier engine? I have several dural undercarriages among my souvenirs including one from the WOT 4 XL which was burned in the Great St Valentine's Day LiPo Fire. If I glue 1/4" plywood between the firewall and the F2 former I could bolt the dural undercarrige to it. This would take the axle further forward than the leading edge of the wing but do you think that it will it make much difference, especially to tracking on take off?
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I won’t answer about your thrust line as I can’t remember how mine was set up but I do remember that the undercart was very pliable.  It did however have a very slow and gentle approach as I remember so I left as is.  Yours however will have a more weighty engine so may be best to go with your ideas and see what looks best.  
Great plane with gentle Aeros.  I’d do another but don’t have the space.  It is a bulky bird!
S

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16 hours ago, Martin Harris - Moderator said:

Why can’t you simply align the crankshaft with the plan?  I must be missing something…

No it's probably me being a bit dim Martin but there is no fuselage plan in the normal sense! Instead there is a half-size drawing which I have found a bit difficult to decipher but then, my sense of spatial awareness is notoriously bad!  Actually it's a bit less than half size, the real fuselage sides are 50" (127 cms) but those on the plan are only 24" long. I've attached a rather unfocussed picture of the plan below. However, having looked more closely at it I noticed a chain-dotted line running forward from the firewall. This is more obvious in the second picture. Having drawn an extension from the chain-dotted line to the half-size picture of the firewall on the right, I've found that this extension matches the horizonal arm of the cross in the middle of the firewall. I assume that this must be the thrustline.

 

I've found a large unused dural unsercarriage amongst my souvenirs. I propose to drill it to the same pattern as that of the WOT 4 XL undercarriage, that way if it is not up to the job I can fit the heavier WOT 4  undercarriage without a problem.

 

I have had to trim all of the formers to get them to fit.

 

DSC01748.JPG

DSC01749.JPG

Edited by David Davis
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31 minutes ago, Ron Gray said:

That’s just given me food for thought, a Phoenix with my (soon to arrive) Laser 150v up front mounted upright with a pot sticking out either side!

 

Sorry for drifting the thread DD!

 

Mad max style. I had a chap do it with an AWXL and a 200v ?

 

That said, with the V you might get it inverted as the carbs do not sit quite as low. But if upright is acceptable then go for that. 

 

Sorry to ruin your plans DD 

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I've just had a look at the Mystic instructions over breakfast and they recommend fitting a second servo for the elevators, i.e, one for each elevator half, if you are using a big engine. They also advise fitting the engine on its side. I was planning on using Hitec 645 servos for the control surfaces but if I were to fit two servos at the rear of the fuselage linked by a Y lead, I could fit smaller metal geared servos.

 

Which servos would you recommend? 

Edited by David Davis
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At the time the mystic was designed servos would barely pull the skin off a rice pudding. A 645 would be way more than the model needs even with only one servo moving the elevator. 

 

My acrowot XL is of similar scope and i use 6.5kg torque servos all round and even then it was because they were what i had lying around. Decent quality 4kg servos would even do if they were set up correctly. 

 

In any case, if you have 645's lying around just use one for everything and it will be fine. If you want to save the big boys for something else then Hitec 485's would be plenty. 

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21 minutes ago, Jon - Laser Engines said:

At the time the mystic was designed servos would barely pull the skin off a rice pudding. A 645 would be way more than the model needs even with only one servo moving the elevator. 

 

My acrowot XL is of similar scope and i use 6.5kg torque servos all round and even then it was because they were what i had lying around. Decent quality 4kg servos would even do if they were set up correctly. 

 

In any case, if you have 645's lying around just use one for everything and it will be fine. If you want to save the big boys for something else then Hitec 485's would be plenty. 

Metal or karbonite gears?

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Wont matter either way. Nylon gears are more than adequate and the Savox 6kg jobs i use in my AWXL and big warbirds are all nylon geared. The only time i have broken them is in crashes or through bashing them on something. Either way, i cant blame the servo. I also use hitec 422's on the ailerons of my Enya 155 powered hangar 9 pulse 125. Its rapid and i have no blowback problems even with those lower spec servos. I even have a futaba 148 on the rudder of my 80'' La7. 

 

I am assuming some mechanical sympathy. Avoiding vertical 1000ft full power dives, using decent linkages without slop to prevent flutter etc. mostly common sense stuff. 

 

 

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On 02/09/2021 at 08:50, David Davis said:

. I was planning on using Hitec 645 servos for the control surfaces but if I were to fit two servos at the rear of the fuselage linked by a Y lead, I could fit smaller metal geared servos.

 

Which servos would you recommend? 

I would try to plug the servos into two channels on the receiver and program the Tx for dual elevators, I wouldn't use a reversing Y lead as I have seen these fail and drive a servo to one end of it's travel. 

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I found that construction of the Mystic became easier once I'd read the instructions and realised that most of the parts, even the stripwood, were numbered! ?

 

1910733242_Numberedparts.thumb.JPG.c90ccbdb55ab547061382477398c8653.JPG

 

The dashboard is very prominent in this model. Does anyone know where I can buy some instrument dials to use on the model? They don't have to be super scale.

 

1129853898_Fuselageinjig.thumb.JPG.e7fae40749496ff6280ba4d4a07aa767.JPG

 

 

 

 

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Think of a full size light sports ‘plane, Google it (instrument panel) look at Images then print to scale to suit model. I use this method but then import the image into Fusion 360 to draw the various binnacles and back plates so that I can 3D print them with the original image printed off for the instrument faces.

 

image.jpeg.8ff75f91a019c257ed85d7e70c72ed42.jpeg

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