TOPMODEL CZ GRAFAS glider - Page 10 - RC Groups
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Oct 27, 2012, 01:11 AM
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Stan Rose's Avatar

Any progress on fitting the Multilock's yet?
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Nov 04, 2012, 01:05 AM
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Stan Rose's Avatar
Today I finished my Grafas.

Having read this thread several times before starting to build I noticed that some earlier contributers have used the recommended motor i,e, MVVS 4.6/840S and a smallish flight battery, only to find that additional weight is required to get the CG in the correct position. I therefore decided to use the heavier MVVS 5.6/690 and 3300Mah 3s Lipo rather than add lead. The result is that the CG came out within the manufacturers recommended range first time and only needed the battery sliding forwards some 10-15 mm to achieve an initial CG position of 80mm from the LE i,e no additional weight required.

Here are the stats:

AUW: 1940 gms (68.4 ozs)
Wing loading: 9oz/ft*
Motor: MVVS 5.6/690
ESC: Foxy 65A (with SBEC and adjustable voltage output set to 6 volts)
Battery: 3300 Mah 3S Lipo.
Servos: Wing - 4 x Hitec HS65HB with Karbonite gears.
Rudder/Elevator - 2 x New Power XL 09 hm with metal gears.
Propellor: Aeronaut Carbon 14" x 8"

The weather here is now wet and windy so that test flying will probably be postponed until the Spring.
Last edited by Stan Rose; Nov 06, 2012 at 01:48 AM.
Nov 25, 2012, 05:02 PM
Just Plane Nuts
Louierc's Avatar

Aileron connectors

Originally Posted by mikmerl
Stan, because I have a lot of models that take up a lot of space I would be hesitant to make the stabs non removable. It’s not such a big deal really but I did have a high adrenaline incident (see post #103)

Piper I like your suggestion of the glue stick.
I will give it a go.
Some time I ago I poured thin CA on the rods and allowed it to dry. It was an improvement so I believe that the glue stick may be worth trying.

Carbon rods cannot be bent. They are either straight (as molded) or broken, there is no in-between state.

Mike - I have purchased a Grafas from a friend. I love the way it flies and I am trying to sort out some minor problems and could use your comments.

The tips are wired with standard servo plugs/cables instead of the fixed multiplug arrangement. This makes it difficult to assemble since the extra wire must be stuffed and folded into the pockets to bring the wing together. I do have reservations about the multiplug, I can see that a small wing gap while flying could cause a loss of an aileron control. I suppose I could open up the pockets and shorten the wire tube to make this easier. What do you suggest?

I am using a Hacker A30-14M with 6.7:1 gearbox on 3S1800 65C and a CAM 18x10 prop. The RX is on a 2S1100 LiFe pack.

Thanks, Louie
Nov 25, 2012, 06:00 PM
Registered User
I used a soldering iron to melt the wing tube to make room for the leads to my multiplex connector. I then found out that the wing tube was not glued. You can push it towards the servo bay, and then cut off the extra length of the tube inside the bay. Neither method requires you to open up the wing.
Nov 26, 2012, 06:49 AM
Just Plane Nuts
Louierc's Avatar
Thanks, I'll look at that tonight !
Dec 04, 2012, 02:20 PM
Registered User
mikmerl's Avatar
Hi Louie,
I am sorry that I did not reply to your questions.
I have not visited the thread in awhile.

I am sure that you have made the mod by now, I have simply used the servo plugs. I consideded the MPX one's too complicated for such a simple task. Why use 6 pins when you only need 3.

In fact I do the same to most of my gliders. See the attachment of my 4m molded XPLORER with just such an installation. Dozens of flights without the slightest problem.

You will get a lot of enjoyment from this glider.

Please do not hesitate to ask for any help.


PS I did a thread for my XPLORER 4000 it may have some tips as well
Dec 17, 2012, 03:09 AM
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rsowder's Avatar
Originally Posted by mikmerl
There is no aluminum wing joiner on the GRAFAS.
It has a strong one piece center panel about 1330mm long with a carbon fiber tube spar.
The outboard panels slide are attached by one 130mm long by 8mm diameter glass fiber rod that slides into both panels and there is a small carbon incidence locating pin towards the rear to keep the two panels aligned.
Personally I would have liked to for this rod to be longer and extend to at least the next wing ribs on both inboard and outboard panels.
I imagine that for normal electric power flight loads it is adequate but I would not recommend doing anything extreme with this bird.
It was designed to be a graceful thermal floater.
Hope this answers your question.
I hope you still check this thread.

I am building the Fascination and the instructions don't tell what type of tape to use to attach the outer wing panels. What do you use on this glider?

Thanks, Randy
Dec 17, 2012, 06:30 AM
Registered User
JoseLG's Avatar
Hi Randy.

For fixing the wing panels for flying you can use electrical tape (its flexible and has sufficient adhesion). I usually put in this area a first layer (permanent) of tape (3M clear tape) and the electrical tape fixed over this. This overtake the possibilities of pulling of the covering.


José Luis
Dec 17, 2012, 11:31 AM
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mikmerl's Avatar
There has been more than one time that I have forgotten to put tapes on the joint and gone off on an hour long flight.

What I am saying is don’t be too worried about using a very specific variety of tape. There is very little force pushing the panels away from each other.

I simply use a 10-12 cm strip of transparent Scotch tape placed on the top of the wing only for convenience. As I am applying the tape I bend the last (towards the trailing edge) 5mm of the tape over so that it sticks to itself. This gives you a handy tab to pull the tape free to remove the outboard panel.

When you are removing the tape don’t pull it upwards as you will probably take the Oracover up as well. Pull the tape slowly horizontally back over itself and this way you will not hurt the covering material.

Best method is to do what Stan has done (see post #116) and that way you can do away with tapes (this is what the manufacturer should have done)

Dec 17, 2012, 02:40 PM
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rsowder's Avatar
Thanks for the great advice José & Mike!

Jan 16, 2013, 01:49 AM
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Stan Rose's Avatar
Since my comments in post #116 I see that Topmodel have now introduced their own version of the Multiplex system and it's cheaper. Well done Topmodel !


Can we now look forward to this system being included in all futureTopmodel kits ?
Jan 16, 2013, 06:25 PM
Just Plane Nuts
Louierc's Avatar
What are users doing to keep the canopy closed? I have been using a piece of tape across the nose and canopy to hold it on. I am not sure that a magnet would hold it when at speed.
Jan 16, 2013, 07:34 PM
Registered User
Hi Mike,
I've enjoyed following your thread. I am curious on your reverse mounted AXI how you mounted the prop and yoke to the AXI prop adaptor. Did you use the collet style adapter that came with the spinner or did you modify the prop adaptor by drilling and tapping it for the bolt that holds the spinner in place? The prop adaptor is 6mm I believe, so a collet to fit 6mm shaft could possibly work I guess.

Feb 01, 2013, 08:16 PM
Registered User
Mike: I'm looking at Pictures 27,28 and 32, did you cover the elevatorr servo in the fin?
Feb 02, 2013, 12:06 AM
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mikmerl's Avatar
Gentlemen sorry for the late response. I did not think that the thread was active anymore but I’m glad to see it is still adding value to modelers.

Louie…..mine has been flying with a magnet in the nose to hold the canopy in place for hundreds of flights. No problems at all. Just use a substantial magnet (I needed the nose weight after all). I have also used a piece of cord to ensure that the canopy will not be lost if it bails out.

bill ……..reversing the AXI motor has been a good solution for me so far. I have used this method on other models as well. See the thread below.

brian…….if you are referring to the round access hole in the tail…….no, I have left it open in the hope that it will allow some air to flow through the fuselage to help cool the ESC, battery and motor. It may be adding some value in that respect as I have never had overheating issues even during our sweltering hot summer days.


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