Help: how to set DX7 heli mode for plane
 

I am trying to utilize the throttle curve found only in the heli mode of dx7 to use throttle curve for a carbon-z yak (electric) to be able to make hovering easier.

Anyone knows how to use the heli mode of a dx7 for a fixed wing plane like the e-flite carbon-z yak?

Thanks in advance!

RE: Help: how to set DX7 heli mode for plane
 

As long as you dont set it in CCPM mode its pretty much the same thing. Swash Type would be 1 servo.

All you really need is end points, dual rates and that.

RE: Help: how to set DX7 heli mode for plane
 

I got a satisfactory exponential equivalent using horns and linkage geometry.

Zor

RE: Help: how to set DX7 heli mode for plane
 

The Eflite Carbon Z Yak is an electric powered 3d aircraft. There are no linkages for Throttle. Throttle Curves are usually employed when the Throttle Response is Non Linear. There is no Expo on the Throttle channel.

RE: Help: how to set DX7 heli mode for plane
 

I've never done that with electric, I do set throttle curves up on my gassers though.

RE: Help: how to set DX7 heli mode for plane
 

I have done Throttle Curves with Gas and Glow. I have not done it with electric as I have not noticed a need, but then again, I have not had any electrics, yet, where I could do 3D and hang it on the prop. I will have later this spring.

RE: Help: how to set DX7 heli mode for plane
 

I have a DX7 and knew there is no throttle curve for the throttle.
That is why I found a method of having some expo equivalent mechanically.

Having so many modelers without adjustable throttle curves I thought it was proper to let them know of the possibility.

Zor

RE: Help: how to set DX7 heli mode for plane
 

Pretty hard to mechanically setup the throttle on an electric.

Just sayin :D

RE: Help: how to set DX7 heli mode for plane
 

Yes D , agreed but since lots of fliers are still using engines as compared to motors and considering all readers I do not feel I created any harm to anyone.

It is nice to have some degree of exponential curve response on the throttle control particularly on straight final approach to landing.

Zor

RE: Help: how to set DX7 heli mode for plane
 

I do not see how playing with the Throttle Linkage can produce an Exponential effect. Besides, the purpose of Throttle Curves is to achieve a more Linear Throttle Response. It is the Carburetor that is not responding in a Linear fashion, despite the fact that the Pushrod is moving back and forth, Linearly.

RE: Help: how to set DX7 heli mode for plane
 

You obviously do not have to take time to figure that out.

Some modelers with gas or glow fuel engines can profit by having less sensitive throttle control in the idling vicinity.

If, as you say, the purpose is to achieve a more linear response, then there would be no need for a control of the throttle curve. Just leave it linear .

In fact the opening or two circles in the carburetor are cause for the opposite.

Zor

RE: Help: how to set DX7 heli mode for plane
 

The reason for the Throttle Curves is to compensate for the fact that the Throttle Response of some engines is not Linear. I am sure that there are other reasons, as well. As you advance the Throttle, the Carb Barrel is rotating continuously, but the engine RPM is not responding in a Linear fashion. You obviously have never seen a radio with Throttle Curve programming. You take a Diagonal Line, and adjust various points on the line, Up or Down, until you achieve the desired Response. With some radios, there are more than 5 adjustable points. You cannot even come close Mechanically. With electric motors and electronic speed controllers, Throttle Curves correct for undesirable Throttle Response, however it is caused. No Mechanics there.

RE: Help: how to set DX7 heli mode for plane
 

</p>

</p>

</p>

Addressed to all readers as usual,</p>

We have to keep in mnd that the linkage from servo to carburetor follows a back and forth motion being tied to rotating objects (the horns). That is itself not a linear motion for the linkage.</p>

We also have to keep in mind that the carburetor opening at idle is a tiny fraction of two circles barely overlapping and creating a tiny opening.</p>

The initial opening from idle rpm opens the carb area in such a way that is not a linear response to the barrel rotation angle. This area can easily be figured out by geometry.</p>

The result is that a lot of increased power takes place due to the few initial degrees of rotation of the carb barrel. Eventually the carb barrel opening from half way to full open does not change the developed power proportionally.</p>

Then, of course, the propeller comes into consideraton by converting the engine power into thrust.</p>

Now we are back to our transmitter stick motion so that we have a finer control meaning smaller thrust variations from our Tx stick motion near idle.</p>

We want the initial Tx stick motions to have less effect on thrust as we move the stick from full idle and gradually gain more and more thrust increase for the same amount of stick movement as we go toward full power. It is an action resembling exponential setting but not necessarily mathemamtical result of a geometrical (mathematical) exponential curve.</p>

It is feasible mechanically for those who do not have curve adjustments on their transmitter.
A while ago I posted five pictures showing simultaneously the Tx stick position and the carb barrel rotation.</p>

I personally felt quite satisfied with the finer power control upon final approach necessary power settings to control rate of descent.</p>

I hope the above is quite clear and I do not intend to carry this discussion any further.</p>

Regards to all readers de _ _ _</p>

Zor

Edited to correct "opening or two circles" changed to "opening of two circles"
03 May 2011 at 20:14 EDT

</p>

RE: Help: how to set DX7 heli mode for plane
 

I'm using my airplane version dx7 in heli mode to get a throttle curve for my pattern plane where smooth throttle management is king.

My problem in heli mode is that I can't get rudder to aileron mix on the L aileron. I've tried mixing AILE-&gt;PIT. &amp; AUX2, in turn plugging the L Aileron servo into AUX1 &amp; AUX2 on the RX, to no avail. The neither of them are slaved to the rudder for the RUDD-&gt;AILE mix.

Maybe I should just ask: WHAT CHANNEL do I need to plug the L. AILE servo into? WHAT do I need to do to enable this?

Please help me out, and we'll get back on the track of the OP who needed help with his electric plane, like me!

Thanks,

Bill

RE: Help: how to set DX7 heli mode for plane
 

[/quote]

Hello Bill (n233w),

I see that you are not getting fast responses .

The topic of thrust versus RPM or versus linearity graph of a transmitter is a complex subject.
Most would keep away from giving it any considerations.

My understanding of the linearity graph seen on transmitter's screen is a display of the linearity of the changes in the modulation pulses that control the servo motion.

I do not consider it to have any meaning in terms of the thrust generated by the engine or motor and the propeller. Many other factors enter into play such as the non linear opening of the carburetor and such things as the propeller efficiency versus RPM and other factors such as the linearity of the control linkage between the throttle servo and the rotation of the carbuetor barrel.

We do not know for example the output power of the engine versus the carb barrel opening and in the case of an electric motor we do not know the motor efficiency graph. These factors are also affected by the propeller used.

As a conclusion we cannot say that if we managed to display an exponential curve on the transmitter display that it really means anything in terms of the thrust control. It may have some effect but we cannot predict the results else than in a subjective point of view.

I wish I could help better.
At least you know that someone read you and cared to respond.

Zor

RE: Help: how to set DX7 heli mode for plane
 

Hey Zor... What part of your previous post had ANYTHING to do with Bill's question regarding Rudder / Ail mixing?

I'm sure Bill appreciated that you "cared" enough to reply ... but I bet he really wished you understood what he asked...lol

Then again, most readers here probably enjoyed your verbal journey into absurdity.

Just sayin'...lol

RE: Help: how to set DX7 heli mode for plane
 

Set the pitch curve to 50 for all the points on the curve. Then mix your ail to pitch.
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RE: Help: how to set DX7 heli mode for plane