I have been wondering what role does the horizontal fin play in the case of helis.
I have seen many helis with it and many without. People have complained that without the fin the helis porpoise. So if they do need a fin for stability why dont all models have it ? All the new models like Raptor 50 Titan SE, Compass Knight 50 Lack this horizontal fin.
Does Align 600N have it ? I do not think so !
Would be good to know what this really is for !
-Gaurav

They seem to have become smaller over time !  They don't seem to do much in terms of flight stabilization (at least in the bigger models), but they help with visually aligning the boom-support rods correctly on to the tail boom. 

Got to try without them on a 450 class heli to see what effect it has on stability for this class of helis.

The Trex 600 has it (so does the 700, but I think the 700 one is even smaller than the 600). 

The Knight 50 has it, but the Atom 500 does not.

The Raptor 50 Titan has one, but the newer Raptor 50 Titan SE doesnt . Plus the Raptor 90 3D lacks the fin too !

They are for tail stableization and and also makes the Heli look good

It tells you in which direction the Heli should move 

Both the hoizontal and the vertical fins will add stability in forward flight and help the model track straight as long as they are completely solid (like in the scedeau/raptor 50 and and other older models)...over time with the focus on 3D flight they seem to have lost their importance... they have become smaller and mere carbon skeletons in helis like the Trex 600/700. The vertical fin has sadly evolved into a mere tail blade saver than anything else. I have seen the newest 3D models have no horizontal fins and mere wires in place of the vertical ones. I for one, miss the classic look of the solid fins....both vertical and horizontal!!

Quote from: lavneetgyani on May 10, 2010, 11:19:14 PM
I for one, miss the classic look of the solid fins....both vertical and horizontal!!

There is a "scale lover"... somewhere deep inside you

Will we see your Trex 600 with AirWolf or MD500 scale fuse

Seriously dude....are you a mind-reader??? I've been drooling over that airwolf body!!

Quote from: lavneetgyani on May 11, 2010, 12:23:34 AM
Seriously dude....are you a mind-reader??? I've been drooling over that airwolf body!!

Airwolf looks cool. Here is a pic.

Quote from: lavneetgyani on May 10, 2010, 11:19:14 PM
Both the hoizontal and the vertical fins will add stability in forward flight and help the model track straight as long as they are completely solid

I think the full size helis answer this to a large part. A good number of them have no horizontal fins, and the vertical fins are only to protect the tail rotors.

Very few full scale helis don't, while 99% do in some form or the other and they are certainly not for show even though their utility is far less than in fixed wings....

As per me in training days ! my instructor told me Horizontal stab are used for
pitch damping in forward flights! and even some helis have negative airfoiled horizontal stab which reduces a pressure on rotor blades/hubs when transistion from forward flights to hover or touchdown by making up quick response to controls!

They aid in stabilization. Question is, is there really a need for such stabilization, especially when it comes to RC helis ?  Seems like we are seeing more and more examples of "not really needed".

i agree with anwar bhai! because even in actual heli they come into picture in forward flights(i.e. speed is more than 50knts or so)
coming to vertical fin here actually fin holds the tail rotor assy so to keep safety height from ground and to cover those drive shaft from main gear box to tail rotor assy they cover with thin sheet often in our language called as "fairings"!(non-structural memeber)
for rc helis there is no meaning in stability! but looks great

Quote from: anwar on May 11, 2010, 01:47:16 PM
They aid in stabilization. Question is, is there really a need for such stabilization, especially when it comes to RC helis ?  Seems like we are seeing more and more examples of "not really needed".

Agree!! But if you see the classic models like the Scedeau is surely more stable in FFF thanks to these fins(better for beginners) vis a vis the Trexes, Vibes....and I cant help but love the classic look they add!! Sigh!!