This may sound rediculous, but it is near impossible to get my 33% GP330L to Stall. I am just starting to practice IMAC sequences. This plane flies so great it takes a long time and VERY low idle to get her to stall. She actually flies great at idle, just real slow. So is there a CG thingy or stick movement thingy to induce a stall for a really stable plane. It's not that she will not stall, it's just that most of the time I have to fly clear accross the entire field to get her slowed down enough to stall before spin entry.

Hmmm.. chopping the throttle and holding her level should stall her.. As she slows it should take more and more elevator till she drops.. is your CG real far back? Maybe your idle is really high..

Moving the CG will not make it "stall into a spin as desired"
This is a very popular misconception.
On any light , properly trimmed aerobat, the CG location works best about 33% - for precision flying NOT flailing flying.
When you add a little elevator at low throttle (idle ) , the model will simply loose speed and adopt a high AOA sink.
Th ONLY thing that will setup the spin entry as desired, is to learn to rather quickly (and sometimes holding in power ) bring the nose up as high as possible with out changing altitude.
IF the CG is proper or even better, a bit noseheavy, the stab will stall and the model will easily break into the spin.

For the spin to work as intended , you must also control yaw till the break is ready to begin --THEN add rudder .
Ideally the nose drop and rotation (one wing panel drops )will occur all at once.
This is how the spin is scored. -If the judges know how to properly score it.
restated :
You must have enough AOA to trigger a "break" -and not get caught in a mushing setup.
We use lots of elevator throw to set this up and learn to put it into effect as fast as possible wihout changing altitude.

tHANKS ALL, My CG is at the back of the range mostly by accident. And my idle is still relatively high. It's a new DA100 still on it's 2nd gallon of gas so i'm still in the middle of tuning transition. I'll try what dick said and things will probably improve with some more reduction in idle speed. I just don't want a deadstick if I can help it; at least not yet.

I got into IMAC interest completely by accident. I have a 2M pattern plane and thought it was a blast to fly; it is, but nothing like the kick I got out of flying a giant gasser for the first time. I now have two 33% Extras and starting a 35% Edge .

Fatten up your throw volume and she'll stall. It is not uncommon to use 30* of rudder and elevator to induce stalling on these planes...

I set up my radio with 75% expo and leave the Elevator thows at 75% of max even in IMAC patterns. Rudder is same expo but 100% rate on all switches. (i.e. no Dual Rate) If I need the volume its there but the expo helps keep it on the high end of the sticks... nothing worse that fumbling for a switch when you don't have enough rudder or elevator...


Besides.. every once in a while its fun to do a wall at the end of a routine!

DP

My 38% Columbo Anderson Extra has 10 degrees of up elevator throw on precision rates (1 - 3/8 inches total Up travel). At this throw the plane will snap and spin (afer a fully developed stall) with great authority. If you need 30 degrees of up elevator to get a stall, you have other issues to solve.

My point wasn't you need it to make it happen... clearly you don't... it is nice to have it there just in case....


DP

I'll take it one step farther, one of the biggest mistakes I see with people setting up their planes for precision flight is using way too much throw. The idea for a precision set up is to always use that absolute minimum amount of throw necessary to achieve the desired flight performance. You will be amazed at how much better the plane flies and how little throw is actually needed.

I let one of our local 3D wizards fly my Extra, set up only for precision. He was absolutely amazed at how smooth it flew and yet how capable it was. 3D throws are really only needed for 3D.

The low % setups are nice for smooth -but for good IMAC you must have more throws available - there is a big difference when flying unknown sequences and have to be able modify maneuvers in a heartbeat.
Some of the very best competition flyers I know, have lots of throws on tap always - but use expo for smoothness -
It really is a learned thing and everyone has his own favorite setup .

Yep, you're probably right Dick. Maybe after I fly a few more contests I'll have a better handle on things. Sorry for confusing anyone out there.

Dick,

What do you mean by modify manuevers?

At the shootout a buddy of mine and myself talked to all the TOC caliber pilots and asked them their setup style for example; what mode do they use, dual rates or flight condition, how much aileron rates. Only one person didn't use any swithes, Mark Leseberg.

dick, i have no idea how to interpret your advice. there is nothing unique about unknowns that requires a different set-up, in fact, i can't think of a better way to advertise execution errors than to have too much throw. modifying figures? forget "fixing" the figure, you already got your zero. and you like low throws for smooth flying - but not for imac? huh?

Here is some input. On my 40% Extra (F/C- Composite ARF type) I found that the airplane would go into a "lul" before it would spin. Essentially it would be partly stalled but would not "break" into a spin. If I started it with rudder at this point it would look like a forced entry. So what did I learn? I would enter the spin just as if I'm landing (more and more elevator progressively added in) as it approached the stall point, I'd add in just a click or two of engine. That would clean up the stab, and give the authority to the rudder for a clean spin entry, without it "wallowing" or "unexpectedly" dropping a wing.

Finally, I've been there, done that with regard to over-shooting a spin entry. How do you get rid of the energy fast without nosing the plane up (and climbing)? Put in some rudder and ever-so slight opposite aileron. Even just a little bit of slip will bleed off speed and slow you down so you can enter the spin in the spot you want without overshooting.

Anyhow, this might be a bit advanced, but these are some techniques I have learned.

Don

Yes, exactly! Not only does adding that click or so of throttle get you some better authority from the stab & rudder, but it allows you to then get the model into a region that gets it "draggier", so you can bring it to the right point in front of you for the break. It's also more apt to show a decent break and thus more susceptible to entering proper autorotation, because you can generally see the right time to kick the rudder over. You don't want to be in that spot for very long. Don, you might remember that I couldn't do this right when you were sitting in the chair at Winston last October, but I was trying anyway! Usually does work though. I haven't yet tried that slip method yet. Sounds like it might be a good way to save the day on occasion.

When I mentioned the increased throw was handy for Unknowns - I did not mean the throws were used to fix a maneuver.

Sometimes the sequences can get busy and you might need to speed up a four point or get into and out of a snap in an awkward wind condition.
The straight cross wind spin entry is a classic example.

Do what works for you .
More time spent flying ,sorts this stuff out eventually----