Twice now it's happened. Coming out of a loop and after achieving a level flight attitude, my hawk continues to decend at about a 45 deg. until the ground stops it!!! Collective full and the rotor rpm seems to be ok. I mean this thing continues to decend from 100ft. I'm running a OS 37, in normal flight it has plenty of power and climbs very well in a vertical accent.

Wondering if the blades are stalled? Full size heli's can get into a situation when decending with power on, where the blades are on the verge of stalling and the pitch in the rotor must be reduced to stop the decent. Just can't bring myself to reduce the pitch when the thing is heading for the ground!!! $75 in parts....

Give forward cyclic, the blades are in dirty air. Though with a 45 degree descent you'd think it would fly out of it. Also back off the collective.

If decending at a 45 degree should'nt you use aft cyclic..? pull back on the stick...
I agree with backing off the collective.

If the heli is dropping at a 45 degree angle, from 100ft, you should not be experiencing the "settling with power" phenomenon. At that angle on descent you should be "seeing" clean air, at least on the forward portion of the disk.

Are you sure you have enough headspeed?

Backing off the collective and applying more forward cyclic should get you going, if in fact you are experiencing the "settling with power" phenomenom.

Rafael

what servo's are you running, could you be stalling the servos? There is a lot of stress on the heli comming out of the bottom of a loop, are you over stressing the servos.

Tell us you config on the Hawk please.

I know a guy who did the same thing, but he got his to come back up just before he was about to hit the ground. The problem was he wasn't running in idle up when he did the loop. As he went inverted in the loop, he went negative pitch on the collective, but at the same time, putting his engine at idle, then when coming out of the loop, he had lost so much headspeed that it struggled to stay up as the engine tried to respool the blades back up. That guy, was me when i first started!

Oh yeah, make sure you have plenty of headspeed if you are doing the loop fast and hard.

^--- Oh, ouch! That's a fair point, however. It's an easy enough mistake...

- Chaz

It sounds to me like too much collective. Your doing the classic..."Its dropping, add more power"...unfortunatly, at full throttle, the pitch is so high, its bogging down the headspeed, and it drops like a brick. This is a hard thing to recognize, because you know you've added power, and you can hear the blades beating the air frantically, so you would think it would pull out....but it doesnt.

Try adjusting your pitch curve to have less pitch and more headspeed at high throttle settings.
Headspeed is critical... too little and it will drop like a brick no matter how much pitch you put on the blades.

Ive tried to teach this principle to newbies. I unplug the motor, and tell them...ok TAKEOFF....
They increase power, but the heli just sits there. I explain to them that while you can see lots of pitch in the blades, without them spinning...it wont work.

Did you use negative pitch at the top of the loop?
Was your engine going to idle in the top of the loop?

Your Hawk with an OS-37 can do nice relatively large or tight (into flips) consecutively if set-up properly.

Sounds to me like you are overloading (over-pitching - collective & cyclic) the engine either from a bad collective/cyclic throttle relationship or a very bad flight technique.

First make sure that your throttle curve to properly match your collective curve to maintain rotor speed through-out its' flight envelope. from 0 to hover to full climb.

First check that you have a set up as described by Steve H in the Century form of RR. This should result in a constant rotor speed at all collective pitch settings with your throttle curve at 100/55/40/55/100 when you have a -10/-5/0/5/10 collective.

for aerobatics, it als helps to have some throttle to cyclic mixing set to also add power when you add cyclic loads (about 50% on the 37)

Then when in FFF, pull back on the stick to enter the loop, ease off to about mid stick (about 0 collective) as you come across the top, while still holding some (not all) back cyclic. Then keep the collective at mid stick (0 pitch) on the down line and start adding back cyclic to pull out at the 3/4 (the 3 o'clock) point to come out level.

If you try this in a throttle curve (e.g. normal) that may be set to allow too much power to come off from 3/4 stick down (specially if you are going to full down stick at the top) then you will bleed off too much rotor speed and your motor will not be able to catch uo to the load when you try to pull out.

Syclic;

I think you and the others pretty well nailed it. Think I'll start with taking acouple of deg. pitch out of the upper end and making sure I'm getting full trottle at high pitch in "idle up" mode. Got to get her flying agian...