How about 150mm like most started out with as an average of the factory suggested CG.
If you are flying off paved surface you can reach ROG speed sooner so 150 is fine. Grass you might want to move it back to 155mm. Which also depends on TV on or off.
But even 155mm is still nose heavy as long as you aren't giving big pitch inputs.

Originally Posted by Maxthrottle

How about 150mm like most started out with as an average of the factory suggested CG.
If you are flying off paved surface you can reach ROG speed sooner so 150 is fine. Grass you might want to move it back to 155mm. Which also depends on TV on or off.
But even 155mm is still nose heavy as long as you aren't giving big pitch inputs.

Thank you I will start with 150 mm and I will see .

Any sugestion about the flap and elevator set up ?

I have about 6 mm at aileron and 3 cm up and donw at elevator !

Originally Posted by toubab

Thank you I will start with 150 mm and I will see .

Any sugestion about the flap and elevator set up ?

I have about 6 mm at aileron and 3 cm up and donw at elevator !

???? 30mm down elevator???? 3mm maybe. For takeoff not. I'm at 165mm so I'm closer to neutral AC.

Originally Posted by toubab

Can someone help me about CG .
I have read this post almost from the begining but still dont know where is the best place for the mayden flyght ?

I will used 6 s 5000 mA
or 2x 3 s 4000 mA

Thanks

Fabrice

I did my maiden using factory in the middle which if I recall is 150. I have also moved my bat's back around 1.5" with no change in handling that I can see. I set my TV's 2mm positive (up). Do not worry that much it looks meaner than what it is. Its a very gentle flying plane and very predictable.

Originally Posted by Maxthrottle

???? 30mm down elevator???? 3mm maybe. For takeoff not. I'm at 165mm so I'm closer to neutral AC.

Really 3 mm up and donw ??
It seams not much !!
what about aileron ?

Fabrice

Ace you don't want to give the impression that its a walk in the park. There is a few videos where even experienced fliers quickly nosed her in on takeoff. One guy even made two attempts and face planted it twice... because it was his first model and he set it with too much movement from the sticks. Some have tried these as their first EDF or first model which isn't the best idea.

Still, its as you say a good stable model with in its margins. Its been getting windier so I have to cut back on the trim set flights but I push my nozzles down 2* in flight and up on landing.

Originally Posted by toubab

Really 3 mm up and donw ??
It seams not much !!
what about aileron ?

Fabrice

Sorry my miss read. You were talking flaps setting and I missed your up and dwn as down only 30mm. So if you show your full stab throw, I assume your ailerons throw is more than just 6mm.

Well...

Now it's for true, I've crashed the Su on the 40th flight .

Same result as V8 and some others before, nose snaped and torn to pieces but the rest of the aircraft is in good state...

After changing everything I messed up in the dumbest of things!

It was an exhibition day and I had the plane ready when a helicopter pilot went ahead of me so I switched off and wait for my turn. When I plugged again I failed to initiate the sequencer because of the nerves and found out in mid-flight after trimming.

Then I started to get obsessed with starting back the device in-flight and completely forgot about flying so I did a bad turn and halted the plane in an involuntary inverted high alpha which I hadn't ever practiced. It lacked the power to recover with a pull up maneuver and the whole thing stalled and went (Very quickly, to my despair ) spiraling towards the ground.

So you see, 39 successful flights training for the show, I arrive and the first thing I do is forget everything and crash it straight away at the begining. Now excuse me, I want to kill myself, give me a second and I'm back.

...

Eeeeeeeeeeeeeek!

Nice thing is the rest of the day went pretty fine and I also maidened my L-39 successfully, but am still ashamed of everything.

Cheers again,
Jandro.

OOoouuuchhh! Jandro. Sorry to hear it J.
Well now you can rebuild the nose the way you want?! Not ideal but....

I'm not looking forward to ever dumping mine but its going to eventually happen. I've added so many little details she's just too pretty to have her face bashed in.

But this is why I prefer foam to composite. Could go down exactly the same way for a lot more money in and to repair.

Ya sorry to hear that Jandro glad to hear you can fix her up. Was it a slight nose into the ground like 45,35,20* angle or more like 60* impact? Since it wasn't on landing sounds like you weren't really going to fast to not cause too much damage. Lil time and work and shell be almost like new.

More like a 60 degrees medium-energy impact...

Maybe it's time to make a CANARDS MOD.

Originally Posted by SU-4ever

Well...

Then I started to get obsessed with starting back the device in-flight and completely forgot about flying so I did a bad turn and halted the plane in an involuntary inverted high alpha which I hadn't ever practiced. It lacked the power to recover with a pull up maneuver and the whole thing stalled and went (Very quickly, to my despair ) spiraling towards the ground.
Cheers again,
Jandro.

Sorry to hear that, Jandro!
If TX allows I try to assign gear switch to the left side of mode 2 transmitter after I crashed MIG by oversteering due to fingers on gear switch. It's almost impossible to control jet for these 2-3 sec you trying to blindly find that far switch with right hand fingers. IMHO on TX all the switches should be on left hand side as this is the only hand you can release in flight.
Can imagine your feelings - on Su 34 and 35 inverted high alpha is really hard - still remember my panic when 34 got stuck there for the 1st time: feels like thrust is cut by half and plane not listening. My solution is now to pull gimball up (aileron roll ends up in violent spin and stall.) so plane goes WOT inverted to the ground. Get some airflow and recover (better by pulling gimball down so you go up into normal high-alpha). If there's not enough altitude - hold it flat and pancake inverted into the ground. You'll damage battery door and rudders abit.

Yes, when I think in hindsight I guess I should have rather pulled "down" (TV up) and complete a half loop-flip. Would have had lots of space and time to recover, didn't expect the Su to behave so badly in inverted. Next time I'm flying I pretend to learn to fly it inverted so as to be better prepared for another emergency like this.

Crashed my SU35 also yesterday Jandro, waiting for video to upload. Crashed it due to loss of orientation on takeoff as my Zippy battery wasnt giving the motors the sound they should have , after flying it for so long already believe me you can tell. So once airborne she didnt gain the altitude she typically does and she leveled out going off into the distance as i tried to keep her up and in the air. So i tried to bring her back however I put my wing cam on the right wing side (i normally put it on the left side), because I already had the plane trimmed out for the wing cam to be on the left side she didnt responed too good...Dumb!!!Dumb Mistake. You learn! I finally gave up and let her go down by pulling back on the throttle and hoped for the best as it was better than a full throttle crash. I walked done to crash site cursing and F'n myself for that wing cam mistake, HOWEVER only the nose broke again!!! Yippy! No major damage and I already fixed her up. She actually looks better than the last fix. Ill post picks and the vid once its done uploading. Video looks worse than it was! After you see the vid Jandro youll understand. I was shocked at the lil damage.

Originally Posted by Maxthrottle

OOoouuuchhh! Jandro. Sorry to hear it J.
Well now you can rebuild the nose the way you want?! Not ideal but....

But this is why I prefer foam to composite. Could go down exactly the same way for a lot more money in and to repair.

Then again when you have the mold to make the composite. You just knock off five at a time and have them ready to go. That's my plan......... Based on all the crashes of late I swear that a frontal composite sleeve would be the cats meow. I think that I'll pop one together and make it a break away!.