Max pitch = max pop

[grumpy]

I purchased a dx7se several months ago and inside the manual packet was a 2 page document titled dx7se setup tips by Alan Szabo Jr. What caught my attention was the max pitch = max pop quote that reads..........Traditionally maximum pitch settings were adjusted to the point at witch the engine would'nt bog with extended full pitch. This was typically 9 to 10 deg. depending on eng. power and setup. The trick to getting maximum pitch response is to program max pitch, typically 12 to 13.5, and then manage the pitch by only staying in this max pitch range for a few moments and only to get the heli to accelerate or stop aggressively (pop and stop). The momentum of the rotor is used to aggressively accelerate the heli initially at these high pitch ranges, then the pitch is immediately reduced to allow rotor rpm to recover. Combining this over pitch technique with the ultra fast response rate of dx7se makes pop and stop maneuvers like grass level tic toc's much more impressive........Being somewhat of a noob I wallowed this little tidbit around in the back of my little helinoob brain thinking, Wow is 13.5 even possible on a T-rex 450. After several attempts during the last couple months I finally can say yes +13.5 to -13.5 can be achieved. And now for my question. Keeping in mind that these high pitch numbers be used momentarily. That means my pitch curve for stunt on my dx7 should look more like an "S" than a strait line right ?  "L" being max neg. pitch  "H" Being max pos. pitch and 1 thru 3 keeping low pitch numbers.   

[mckrackin]

The collective management Szabo is talking about can't be programmed in.It's all in moving the stick manually.
That's what he's bragging on the radio about.The fact that you can burst it full collective and back off in the blink of an eye and the radio and servos can react as fast as you can move the stick.

Your pitch curve should be straight from 0 to 100.

[grumpy]

Kool, Just thought that keepin smaller numbers around center would help to come back off max faster and keep rpms up. Just tryin to learn something new. And as far as the radio Wow! what a difference. blue-norm. black-st 1 - red st2

[mckrackin]

Having low numbers in the middle will make it pogo.
Backing of the throttle would be too jumpy since it would go from full pitch to zero pitch fast.
Also,low numbers in the middle will give it negative pitch while still above half throttle.
It would be very hard to control.

[grumpy]

Yeah dont want em any harder to cotrol than they allready are.

[nheli]

To sense and feel the fast connection/response with the DX7se, only Szabo and those top gun pilots can do it.

[grumpy]

Yeah, nice. DX7se + ar7100 2048 lines of resolution you can't fart without it showin up in your heli.. Thank the heli gods i bought one. As for not being able to feel the speed/responsiveness I use the same equip as they. I may never be as good as the top guns but I do have one big advantage I'm retired/disabled so if I want to go flyin every day all day I can do that. Eight lipo's Two trim heli's and my opinion the best 7ch. radio gear on the market. Besides isnt it fun

[mckrackin]

I was doing some 3D once for the first time in front of a crowd.
My nerves were terrible to the point of actually shivering.My hands were shaking THAT BAD.

Well anyway,people noticed and commented that the heli was shivering with me.
AND IT WAS!!! lol....

[dditch66]

Having low numbers in the middle will make it pogo.
Backing of the throttle would be too jumpy since it would go from full pitch to zero pitch fast.
Also,low numbers in the middle will give it negative pitch while still above half throttle.
It would be very hard to control.

+1 on McK

If you don't have a linear pitch, your gonna be flying a YoYo.

I personally am not a pop attick.  I've seen some guys set up helis with all this pitch and punch and then just hover and pump the cyclic up and down showing off all the pop, then they don't do anything.  I personally think that you will benefit with LESS range and work on collective management (timing of the movements of your collective) in order to maintain altitude and such in your flips and tricks. 

Another thing to worry about is binding at the extremes.  Full pitch and full back cyclic, will the heli swash bind? Gotta check that or you gotta not do the extremes of both sticks.

Some people will run flat throttle curves and load up the rpms at 0 pitch.

[grumpy]

Swash starts touching frame at -14. but at -13.5  full cyclic in any direction close but does not bind. +13.5 you cant get a hair between washout and the end of travel but does not touch. and if I run a strait thro curve my head speed is so high at 0 pitch that It burst the rotor disc, Been there done that and dont like blades flyin by themselves.  

[mckrackin]

If the swash is close but not touching,it will still likely bind.
Give it full pitch either way.Now give it full left or right aleron.That moves the swash even more and will probably hit.
Check the same with for and aft elevator.

A flat throttle curve doesn't have to be 100%.
You can set the curve at a flat 50% if you want.
Find an RPM you like.
My throttle is a flat 100% on my 500,flat  90% on my 450 and I haven't had my 250 wide open yet so I don't know.

[dditch66]

If the swash is close but not touching,it will still likely bind.
Give it full pitch either way.Now give it full left or right aleron.That moves the swash even more and will probably hit.
Check the same with for and aft elevator.

A flat throttle curve doesn't have to be 100%.
You can set the curve at a flat 50% if you want.
Find an RPM you like.
My throttle is a flat 100% on my 500,flat  90% on my 450 and I haven't had my 250 wide open yet so I don't know.

He's correct. You also want to check the corners. You may not think your gonna ever do this but you never know what you'll need if your bailing out of a manuever.

you may also notice that servos may max out before the end of stick movement if you achieve your max/min pitch with a swash mix over 60%

[grumpy]

You guy's have valid points but this is why it took over two months to finally reach this max pitch. it is so much more than just making sure that the swash doesn't bind and servos are within limits for instance, At -13.5 swash does not make contact with any part of frame full left-full right-full back-full forward-or any combo of the above, no observable indication of binding even while test run at 50% throttle...but upon closer inspection servo horns on the elevator and right aile servo come within 2 mm of main gear at full right or full back, not a big problem considering my control linkages are not at the last hole a little trimming the servo horn now I can have 4 mm clearance, Full right - full back. And no I didn't tweak the swash mix, still set at +60. I seriously doubt I will ever have the need for such high pitch numbers, but if I do.............. 

[elkmaster01]

Whats wrong with an 'S' pitch curve? Take a linear pitch curve and add expo,,'walla' you have an 'S' curve. There's more than one way to skin a cat!!

Randy

[mckrackin]

Expo in a straight curve makes a "C". 

Expo also doesn't really change the pitch curve.Only the speed the servo will get to it.