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Aug 24, 2019, 08:24 AM
Don't hate bro
Quote:
Originally Posted by kallend
"It can't happen to me" has caused a lot of accidents over the years, in many walks of life.

Despite all the warnings there are still members of my club who haven't properly set their throttle cut.
Some of the older guys in my club are getting newer radios and they are impressed/amazed with the throttle cut and say they really like the feature. I'm guessing maybe older radios don't have it?

Another safety item often overlooked and ignored is setting the failsafe properly. I'm even guilty of this possibly and need to spend some time checking out my planes for proper failsafe operation. A throttle cut not working is most dangerous to me, an improperly set failsafe could be dangerous to many.
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Aug 24, 2019, 08:28 AM
Flying R/C since 1964
kallend's Avatar
Quote:
Originally Posted by bcrc
I have a DX9 with the latest software.
Under "Aircraft type", "Wing":, what is the difference between "Elevon" and "Elevon-B" ?? Why the letter "B" ??
Thank you.
To get both elevons moving in the correct directions for both pitch and roll inputs, one or both of the two servos may need to be reversed depending on the linkage geometry. Even so, it may be necessary to exchange the left and right side servos to get everything working correctly with "Elevon" wing type. If this turns out to be the case, then "Elevon B" achieves the same result electronically without having to swap the servos over. It just makes setup easier.

Bottom line - start out with "Elevon", and if you can't make everything move correctly in the servo setup menu, then go back to wing type and try "Elevon B"
Aug 24, 2019, 09:50 AM
Registered User
Quote:
Originally Posted by JPJI
Yep, been there, done that. Arm plane with throttle cut at -130%, throttle stick at lowest position, turn off throttle cut and wham, props start spinning at 30% and no way of stopping them with the throttle stick!
Lesson learnt. Throttle cut always at -100%.
I hope you can clarify...

Is this "out of the box" behavior for Spektrum transmitters and receivers? (I am only flying a couple of different HH BNF aircraft.)

Or does this only happen ONLY if you do a throttle calibration (with throttle cut at -130%)?

I have changed the throttle cut to -100% so Ishould be safe now, but...

In the past (when TC was still -130%) I never noticed that turning off throttle cut with the throttle stick pulled back that the motor would start spinning.
Aug 24, 2019, 12:07 PM
No bounce, No play.
davidmc36's Avatar
It depends on ESC type. Some will notice the -130, some will not.

The -130 is default on the DX transmitters.
Aug 24, 2019, 12:35 PM
65 years of RC flying
Daedalus66's Avatar
The -130% default Throttle Cut is a relic of days when models had glow plug engines that idled at low throttle (nominally -100%) and that could be killed by pulling the throttle lower, either with throttle trim or with throttle cut. If you used trim, you had to find the correct idle setting next time you started up, but throttle cut didnít affect the idle trim setting.

Nowadays, with most models electric powered, throttle trim is normally disabled (by setting to 0 in Trim Setup) and throttle cut is set to -100%.
Aug 24, 2019, 02:03 PM
Multi-Platform Pilot
barracudahockey's Avatar
-130 works for most of the e-flite speed controllers, some auto calibrate the throttle setting as has been said before so -100 is safest.
Aug 25, 2019, 04:52 AM
Blue Skies
hifinsword's Avatar
As Andy has said here a few times, the low THROTTLE TRAVEL value in the SERVO menu should be the same as the THR CUT value for electrics. And the THROTTLE TRIM should be disabled for electric models. If you change the TRAVEL value, do a calibration also. The subject of THR CUT has come up a few times in my club's monthly meetings. It's become a subject more and more are becoming aware of as new Txs are bought and new members flying electrics come into the hobby.

I think Spektrum is behind in changing the defaults, or they feel the -130% is safer for most of us. I'm guessing they think the IC guys will still need that -130% setting and going to -100% as a default would not work for them, or be unsafe? If there was an ELECTRIC or IC mode selection in the menu, that would help and then an automatic value would set the default for IC or ELECTRIC. But that would probably require more memory than is available in the DX line of Txs?

Spektrum also has legacy menus wording such as GEAR and FLAPS when Channel #s would work better. There may be a reason why they've stuck with those, but I can't figure out what their reasoning is.
Don
Aug 25, 2019, 05:15 AM
No bounce, No play.
davidmc36's Avatar
Quote:
Originally Posted by hifinsword
:

Spektrum also has legacy menus wording such as GEAR and FLAPS when Channel #s would work better. There may be a reason why they've stuck with those, but I can't figure out what their reasoning is.
Don
New Rx's have numbers.........so there's that.
Aug 25, 2019, 06:30 AM
Always trying to learn
mejmea's Avatar
Quote:
Originally Posted by hifinsword
As Andy has said here a few times, the low THROTTLE TRAVEL value in the SERVO menu should be the same as the THR CUT value for electrics. And the THROTTLE TRIM should be disabled for electric models. If you change the TRAVEL value, do a calibration also. The subject of THR CUT has come up a few times in my club's monthly meetings. It's become a subject more and more are becoming aware of as new Txs are bought and new members flying electrics come into the hobby.

I think Spektrum is behind in changing the defaults, or they feel the -130% is safer for most of us. I'm guessing they think the IC guys will still need that -130% setting and going to -100% as a default would not work for them, or be unsafe? If there was an ELECTRIC or IC mode selection in the menu, that would help and then an automatic value would set the default for IC or ELECTRIC. But that would probably require more memory than is available in the DX line of Txs?

Spektrum also has legacy menus wording such as GEAR and FLAPS when Channel #s would work better. There may be a reason why they've stuck with those, but I can't figure out what their reasoning is.
Don
I think you may be correct in that there is a lot of legacy/inertia in what's done (not uncommon in many products, right?)

Another example is the fact that when you do cross trims the display doesnt change to reflect that fact. I remember Andy saying that was because the original programming protocol was dictated by someone who felt that's how it should be, and it's just stayed the same ever since. That seems backwards/confusing to me but at the same time a manufacturer who is "invested" in a particular path has to balance multiple factors in making such changes. Frustrating at times for all involved I'm sure....
Aug 25, 2019, 06:54 AM
ancora imparo
jj604's Avatar
Just be aware that there are electrics that require the Spektrum -130% value of throttle cut. This is likely to only be true of Bind N Fly models with stabilised flight controllers. The X-Vert is the best known of these - there may be others.

Only an exact -130% will actually cut the throttle - and it is a function you need in order to land reliably.

John
Aug 25, 2019, 08:04 AM
Registered User
Cherokee Flyer's Avatar
I guess in passing I must be the only one left in whole world who doesn’t just fly electrics, in fact I usually don’t. For that matter, very few at my field fly electrics. My, I guess glow isn’t dead!

L.
Aug 25, 2019, 08:09 AM
Blue Skies
hifinsword's Avatar
Quote:
Originally Posted by jj604
Just be aware that there are electrics that require the Spektrum -130% value of throttle cut. This is likely to only be true of Bind N Fly models with stabilised flight controllers. The X-Vert is the best known of these - there may be others.

Only an exact -130% will actually cut the throttle - and it is a function you need in order to land reliably.

John
Yes, that is true John. If I worked at Spektrum on creating new models, I would make sure that the ESC, throttle settings values and THR CUT settings were spelled out VERY CLEARLY in the operators and owners manual for these exceptions to the 'rule' - the 'rule' being Andy's guidelines. Otherwise, the vast majority of us that don't require those specific values, are burdened by the requirements of a few.
Don
Aug 25, 2019, 08:48 AM
Don't hate bro
Quote:
Originally Posted by Cherokee Flyer
I guess in passing I must be the only one left in whole world who doesnít just fly electrics, in fact I usually donít. For that matter, very few at my field fly electrics. My, I guess glow isnít dead!

L.
The opposite seems true of many other places. Electric planes are becoming very popular at my club as the membership keeps growing with many new, younger members entering the hobby. Also, any people don't even fly at clubs, and most of them likely fly electric.

Why is your club stuck on glow? Heck, many of the ol boys at my club have at least moved to gas.
Aug 25, 2019, 08:51 AM
65 years of RC flying
Daedalus66's Avatar
Quote:
Originally Posted by Cherokee Flyer
I guess in passing I must be the only one left in whole world who doesnít just fly electrics, in fact I usually donít. For that matter, very few at my field fly electrics. My, I guess glow isnít dead!
L.
Iím one of only a small handful of people in my two clubs (total membership nearly 200) who ever fly a glow powered model with engine less that .40 cu in. And the .40 to .60 powered models are rapidly getting rarer. More and more, the choice is between small or medium size electric and big or giant gasoline (over 15cc).

Since the requirements for throttle cut in a gas-powered model are quite different, it looks like Spektrum should recognize the dominance of electric among the users of the Throttle Cut feature and seriously consider adopting -100 as the TC default.
Aug 25, 2019, 11:57 AM
Electric baptism 1975
DavidN's Avatar
"If there was an ELECTRIC or IC mode selection in the menu, that would help and then an automatic value would set the default for IC or ELECTRIC."

YES.
Gas & Glow need THROTTLE CUT to stop. Electric needs it to prevent premature start. I believe this is an important safety issue.


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