Yes, S3010 is available in RF8. Did you already select Mots and Props?
And do you prefer a certain design, color and Name for this project?
I plan to use four low cost Emax CF2805 1600KV with 3s batterie. But these motors were re-wounded and I don’t know the new KV. Propeller diameter will depends on the final weight but it will be between 7 and 8 inches.
Is black cat a correct name ?
no color preference.
BlackCat sounds good to me, but I think they don’t like water 
Your SITL Demo looked like a Black Duck 
I was out last week and I am late for reading all posts.
About power consumption:
your CG calculation gives a comfortable margin, good to start but should be reduced if you want to reduce a little the power needed for fixed wing flight.
As a copter weight = power consumption and as a FW drag = power consumption.
Propellers are also very important, Graupner elektro prop, this kind https://www.studiosport.fr/helice-horaire-graupner-elektro-prop-8x5-p-3453.html , are best CW/CCW propellers I have tested. They are a little expensive so for debugging I prefer to use their Gemfan clones available in soft plastic or reinforced with carbon powder. Soft ones 10 inches are OK and reinforced are sometime impossible to balance. DJI motors and propellers look efficient, 6.4g/w at hover is a good value for a small 6 inch propeller. I like the idea to switch off motors in FW flight but to get most of it folding propellers would be nice.
Thanks for commenting.
You mean the CG calculation with eCalc - cgCalc - Center of Gravity (CG) Calculator for RC airplane, flying wing, delta or canard
When I understood right, this is (to) much in front and could be moved direction back?
This could explain, why with the same wing the elevons where deflected upwards and the consumption in FW disappointing high. I moved it 12 mm backwards, but with bad feeling. And even then they where deflected ~8 ° upwards. Is this a correct interpretation of the CG location? (no experience in FW flights)
Here: https://www.youtube.com/watch?v=nIXRRIeIZe0&feature=youtu.be
In this case I will design the new copter tailsitter that i can move the akku backwards later.
@kd0aij,
I set the Black Cat here: https://drive.google.com/open?id=1UajY80phpmUiP-Ca7gWTcwx3mdrC5W9C
And adapted the physics in RF8 as much I knew on the base of your BlackLetpi.
But not yet tested in RF8. May be this time, we win the race to be airborne against @losawing 
there are two very different aspects
First one is stability: stability condition is simply CG in front of neutral point.
Second one is equilibrium: pitching moment sum =0. The reference point to calculate this sum is CG position. Contributions are from the lift force, the airfoil itself through the Cm coefficient, control surfaces and tail if there is one.
Come back to tailless airplane: lift force behind CG brings a negative contribution, airfoil a positive one provided Cm is >0 which is better for flyiftng wing. The balance is done with control surfaces. This is where I answer your question : the more CG is in front, the more control surfaces have to be deflected upward and the more you increase drag for a given lift.
Why we do not use traditional airfoil for a tailless plane ? Because the Cm is negative and the wing to fly level would need a lot of upward elevons deflection that would destroy airfoil performance. But do not expect a huge performance improvement, a camera or some wire on the outer surface of the airfoil add probably more drag.
That about all I know, this is probably a little rough and maybe not very accurate but good enough for our hobby.
Thanks for the explication. Is the deflection in the vid before good/normal or better less than 8°
Difficult to answer your question, I feel 8° deflection is a little high but not crazy.
12A on 3S at 50km/h is too much for a small wing. It should be between 5 to 8A. I believe all the electronic you had on the top of the wing produce a high drag. 50km/h is probably a little bit high for a foam wing as this kind of materials have a rough surface and the drag is a function of V²
@lorbass I made some changes to your BlackCat model physics, and I think I the fuselage is closer to correct now. At least it seems to be creating more drag now and the flight characteristics seem more realistic. It’s flyable in manual mode with the current CG.
I also changed the vertical fins on the top wing to be children of the wing, but couldn’t figure out how to add a second child pair so I made the one pair twice as large. The RFX and parameters are here:
I’ve uploaded a video from RF8 showing that this design can tumble very rapidly in pitch; recovery is possible, but somewhat difficult. Switching to FBWA seems to be a fairly safe way to recover.
@losawing @iampete and @lorbass: I’d appreciate your thoughts on what’s going on with longitudinal stability and why it flies better in ACRO mode than it does in QACRO.
cool!. I Guess the only difference must be the gains. How haw you done the control surfaces? The front wing with ailerons and the rear with elevons? I guess you could also swap left and right on the front wing and have elevons canards. That might get abit exciting. I have high hopes for Qasist with plane in control of the control surfaces. Maybe try this in acro (you might have to enable this in the code, i think Qassist might be locked out in manual and acro) rather than Qacro. There is also a new Q_TAILSIT_OPTION param to turn this on.
The front wing is canard elevons, since that is how @losawing set up his small depron model:
As I mentioned above, it actually flies better in ACRO than in QACRO, but I’ve
found a simple change to the tailsitter speed scaling which makes QACRO perform well also. Of course the change is to make it work more like the plane pitch controller 
And it seems clear that the high-rate tumbles are a result of letting the airspeed drop too low and stalling both wings.
It is possible to reduce the odds of that in either acro mode by reducing the max pitch rate. At 120 deg/sec, it will do inside and outside loops continuously without stalling/tumbling.
Great to see it flying. May be the painting should be different to see better what up/down or front/back.
Try to use copy/paste in the left field of the editor.
This is a great design that has great flight characteristics, I am impressed it fly manual, my depron is not flyable in manual mode and recovery to fbwa did not work. Take off from water as a plane is also very impressive. I hope the real one will fly as good.
Q_A_ACCEL_P_MAX = 8101.124023 seems to be a very small and Q_a_rat_pit_I very high. Is it the result of q_autotune ? I am also currently playing with FLT parameters and saw a great improvement but that need to be confirmed. Differential thrust is disabled on my depron, I feel it is better for Qacro.
@iampete did you gave up with qasist ? I remember I saw it working one time among all binaries I had tested and that was impressive.
Control surfaces are always ventilated by propellers and both my biwing and depron are impossible to stall, this is a real strength of quad X plane.
I can build you a test firmware, hopefully it will get into master eventually.
yes, I would be pleased to test q_assist. For the moment I only have my biwing and my depron which are RTF so 2 quad X aircraft.
which flight controller are you using?
fmuV3
fmuv3
fmuV3
I wrote it several time because system require more than 20 characters:upside_down_face:
1 Like