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Old Aug 30, 2014, 11:08 AM
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Arxangel's Avatar
Bulgaria, Sofia-grad, Sofia
Joined Feb 2012
1,672 Posts
Quote:
Originally Posted by Soto48 View Post
Hi guys, just simple question , where's the CG ?, is it inline with the servo cable? seem I can't get it right , I have nose heavy day
Instructions state 62mm from Leading edge of the wing, and I've flown it this way, and it seemed OK. People have suggested that the CG could be a little further back, but 62-70mm is a good place to start.
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Old Aug 31, 2014, 09:07 AM
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Singapore
Joined Apr 2010
103 Posts
Hi Arxangel. I juz maidened the plane and found it yawning to the right a lot when ever I throttle up. Indeed, it made it so hard to take off for me, when trying to fly it from a running track with a lot of obstacles around me. Btw, may I know how is the 3D printed motor mount worked for ya, and what is the best setup that you have experimented so far for a decent one hour flight? And btw, is it possible if you could send me a file for the 3D printed motor mount, cuz the nose down problem is killing me! Thanks a lot and I wished I had seen ur thread earlier!
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Old Sep 01, 2014, 07:07 AM
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Spain, CT, Teià
Joined Dec 2013
17 Posts
Quote:
Originally Posted by McG6969 View Post
@llubi

It is quite fun that we both come from 1:1 scale machines to RC models.
I did spend some years flying ULM & Experimental - 2 seater - small planes.
My first solo was in an ‘old’ French Albatros pusher w/ a remarkable cockpit view (perfect for FPV…). My instructor owned a R22 and helped me ‘dominate’ the beast. Later on, I’ve been building 2 Exp’s from scratch and highly modified an Italian Storch w/ a Vne of 235 km/h… yes, an ULM.

Back to topic:

Concerning the Raptor V1, it exists in 2 different wingspans (1600 & 2000) so, your Spanish fora people probably talked about ‘upgrading’ to 2m. As for the V2, the fuselage is the same but the wing airfoil & tips are totally ‘different’, even the stabi & vertical fin aren’t the same profile and configuration; the motor mount angle is increased allowing easier hand launch or/and the use of a larger prop. People pretending it is just a ‘grey’ painted V1 should do a bit of longer research.

As Arxangel wrote, with moderate weight and fair load distribution, this machine is flying like a bird.

Btw, the Raptor/Ranger fuselage isn’t PVC but a PP (polypropylene) formula ‘mixed’ by Volantex and very probably the best ‘pro’ of these machines.

Anyway - and in my humble opinion - both the Raptor & Ranger show a far from optimal tail design as the stabi should be as much as possible centered in the wash of the engine. Meaning that with the V1 & Ranger motor mount, the stabi/elevator should be above half of the vertical fin.

Even worse w/ the upgraded V2 mount w/ ‘upset’ thrust angle, the tail is nearly not receiving any wash anymore at low (take off/landing) and medium airspeed making the controls very 'floaty'. Only when the airspeed gets higher, a more correct boundary layer gives increased control to the tail surfaces.

But then, installing a landing gear - and thus increasing the angle of attack - gets to make things even ‘more bad’ as the machine tends to rotate (take off) without enough airspeed for the controls to get fully operational.
I wouldn’t imagine mounting a landing gear on the V2 without modifying to a T-tail configuration or close to it.

Regarding the cam, I’ve got a GoPro as well but the Mobius is really more suited for inboard video or FPV. For a few Euros, there is even a 20 cm lens cable allowing you to put the lens in a very confined place at the front and installing the camera unit more aft (closer to CG).

I’m certainly not into full FPV yet, but I still don’t see why you need a small - mostly ‘bad or average resolution’ - cam AND another one for recording. Is it a matter of redundancy? But then if your FPV cam ‘quits’ or looses signal, you’re ‘blind’ anyway? Still a lot to learn, I’m afraid…

Concerning the Catalina, why not considering putting some flaps on it, or mixing your ailerons to ‘flaperons’ if your Tx allows it?

By the way, if you look at your seaplane, as with my 'theory' above, it has a mid tail configuration allowing the stab/elevator to be totally centered in the engines washout...

Happy ‘patient’ landings

McG


@arxangel > please correct the above if I’m writing some ‘stupidities’…
Wow!! 235! I made that with my ex-boss, he had some toys, and I really loved that, but laws changed in Spain, also I changed of work, so... Now just playing with RC models

I was writing without some hurry, so I don't explained so well. In Spain, people use the glyder wings, to avoid the plane to "fall to side when stalling" and also to have this "head weight" problem. Problem is that I'll have to make some modifications, installations, tests,... and my time is not enough, if I also have to do more major modifications to make the plane fligt as expected... Am I explaining well? It's just I "want" a plane RTF (RTF= modyfing servos, motor,... but not wings, or doing 70 tests to make it fly).

I read a lot of the Mobius, but as I have the GP and the gimbal from the multirotor, I just want to "use" it, and not have it inside a box But I'm trying my partner to buy it, and then if I like, I may try

Do you think they will upgrade to T-Tail? Because in a foamy you may modify the tail, but in this PP... I don't think you can do that at home!

For FPV, first is an autopilot with RTH function, in multirotor, in plane, in everything, now prices are so low, and it's a plus in security, also to start testing and then improving. The thing about 2 cameras is just a matter of comodity, video from GoPro for FPV is not the best, it's so modified and it's difficult to land. From the mini-camera, what you see is what is, so it's easy to make a fly.

About the Cat... yesterday I was flying, for first time in last 3 weeks, the horn of the elevator servo broke in fly... I'm thinking in buy today the Ranger, or buy a new fuselage, because this one is reparable, but... too much to do! A new point for good servos!

I have the Taranis with the Flaperon mix to slow it down, but I think it need to much more weight, with a 2.2A 3S battery, it can glide for 50-70 meters without throttle, and without loosing control, I was going yesterday to test flpaerons, but I couldnt

@Arxangel, any news on buying your upgraded motor mount?
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Old Sep 01, 2014, 07:57 AM
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Bulgaria, Sofia-grad, Sofia
Joined Feb 2012
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Actually the Ranger is NOT easy to stall, especially if you have an AP stabilizing it.

As for the motor mount, as of this moment I can tell you that it allows mounting of a larger prop, and possibly makes the nose down issue a little less pronounced, but I can't say that it doesn't introduce other problems, because mine seems to have developed a right yaw in the air!!
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Old Yesterday, 02:25 AM
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Belgium, Flanders, Zaventem
Joined Aug 2014
8 Posts
Quote:
Originally Posted by llubi View Post

... It's just I "want" a plane RTF (RTF= modyfing servos, motor,... but not wings, or doing 70 tests to make it fly).

... I read a lot of the Mobius, but as I have the GP and the gimbal from the multirotor, I just want to "use" it, and not have it inside a box But I'm trying my partner to buy it, and then if I like, I may try

... Do you think they will upgrade to T-Tail? Because in a foamy you may modify the tail, but in this PP... I don't think you can do that at home!

... The thing about 2 cameras is just a matter of comodity, video from GoPro for FPV is not the best, it's so modified and it's difficult to land. From the mini-camera, what you see is what is, so it's easy to make a fly.

... About the Cat... yesterday I was flying, for first time in last 3 weeks, the horn of the elevator servo broke in fly... I'm thinking in buy today the Ranger, or buy a new fuselage, because this one is reparable, but... too much to do! A new point for good servos!

... Flaperon mix to slow it down, but I think it need to much more weight, with a 2.2A 3S battery, it can glide for 50-70 meters without throttle, and without loosing control, I was going yesterday to test flpaerons, but I couldnt

@ llubi

I just think you 'll have some difficulties to find an RTF model that flies 'perfectly' right out of the box if you double its dry weight (MTOW at double of the standard weight), and that's what you are doing with your FPV stuff, electronics & batteries.

If your friend buys the Mobius, you will certainly want to have one too... and getting the GP out of the box for your field vids.

Concerning the T-tail, I have no idea if Volantex is intended to make one.
It shouldn't be that difficult though as the tail and stab have nothing to do with the PP fuselage. Tail and stab are EPO bolded together w/ some ABS parts.
I don't have a Ranger but I'm planning of building a T-tail (w/ integrated servos) that can just be bolted to the Raptor V2.

Sad that you damaged your Cat badly. If you go on with it, a nice choice of servos are the 929MG from Corona ( I think Arxangel is using them too following his reviews). Analog but strong and efficient. You can always use the 939MG (digital) for the elevator if you prefer.
The last versions of the Trainstar (trainer plane also from Volantex) now have a 15-17 gr servo for elevator. That's maybe also a way to go.

I believe that 'flaperon'-mix is the way to go as you can adjust it the way you want.
If the gliding ratio is really too important, the ultimate solution would be installing 'airbrakes' next to the fuselage but as I understood you don't like to 'modify'...

Good luck in repairing the seaplane

McG
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Old Yesterday, 07:22 AM
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Germany, RP, Weißenthurm
Joined Jun 2013
283 Posts
Ranger Ex: Take Off and Fails (0 min 56 sec)
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