Can someone tell me if
THIS and
THISwill work together and is this a good choice for failsafe and reliability on my first quadcopter.

Thank you,

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Kevin, I have 6 Nitro powered airplanes.  Some of them are pretty fast!  This one is almost 200mph.

 Not a single one has a spring on the throttle.  I've never even heard of such a thing in 20 years of doing this.  Maybe they are doing it now, or maybe they're doing it on gas engines.  I have no idea.  But this was in no way Standard Operating Proceedure when I last flew, nor was it in the MAAC safety code.

But  radio range check before every flight, was.

I honestly don't see how you could possibly have a spring strong enough to force an unpowered servo to close, that also wouldn't cause a problem for that servo if you were trying to fight that spring for the whole flight.  Well, I have some coreless servos now that have little resistance when unpowered, but something like an HS422?  No way. 

Jake:  Pull the plug?  What plug?  What are you talking about?  There's no spark plug on a Nitro engine.  

I do not think the argument you have put forth makes any sense either. That's not my argument, I never made it, don't try to create a strawman.

My point was simply that the 9X failsafe is NOT logical, it's stupid.  You are suggesting that the 9X has a wonderful failsafe that is defeated by the APM, and that's false.  The 9X failsafe is stupid, and the APM just fails to fix it.

One solution to your problem is to never start the engine until the APM is booted.  Another solution is to not cause reboots while driving (watchdog reboots).  And finally, don't put an APM on a fast nitro powered ground vehicle.  What really are you trying to do?

I have never had an APM reboot unexpectedly in all my testing.  

That spring will not close a throttle controlled by a standard servo.  It is only there so that it closes if the linkage fails, and it helps make the throttle control a little more precise.  It is NOT a failsafe for radio failure!

Here is a discussion where airplane pilots are talking about REMOVING the throttle return spring on gas engines because of the problems they cause. 62% of them say they disconnect it.

A really good discussion on the topic from heli guys.  You'll notice he mentions at the beginning that nitro powered helis have not spring at all, this is only for gas engines.  He talks about the pros-cons of the spring.  One con is that it can CAUSE throttle servo failure, and that it cannot close the throttle anyway if the power is removed from the servo.  The little springs can only close an unpowered CORELESS servo, as I have said.  So, do you run coreless servos on your throttle?

Another talking about springs preventing proper operation:

We're not talking about full size cars here, Kevin, so recalls to Fords do not apply.

I'm quite happy with the 9X, as most other people seem to be.

Before this issue came up I hadn't thought much about failsafes and range issues.  When I finally did research the issue I found out that the 9X does exactly what I expected a transmitter would do on signal loss (at least on the throttle).  If a RX isn't receiving a signal, it shouldn't put one out.  If it is and you didn't somehow specifically set that up somehow that's runaway behavior IMHO.

So I don't really see any reason to switch to a system with some odd behavior or pay extra for one with extra options I don't need.  If I'm going to go to the trouble to set up some special failsafe options I want to do it right in the APM where it can be handled in a smart way.  

Updating the PPM processor doesn't really seem all that difficult.  It needs to be done anyways as the throttle line disconnection bug is essentially the same issue and also needs to be fixed.  I'm pretty much grounded anyway until that is fixed and I can fly safely without risking an out of control plane endangering someone, which I don't feel is the current situation.  For my application I have to be able to guarantee that the system will shut down if it loses control or goes haywire.

When this bug is fixed I'll have a failsafe system 100's of times better than anything out there.  At that point it will be the people with expensive transmitters that are crying because their expensive receivers can't do the most basic and logical option of turning off the throttle signal when they aren't receiving one.  On my 9X system it will be very easy to detect RF signal loss.  Everyone else will have to figure out how to do that with their systems because my advice to them will be to buy a proper transmitter, like the 9X, that is smart enough to turn off it's output when it's not getting input.

Jake, if you're up to it, why don't you have a look at the PPM code and suggest some improvements.  There are developers following this discussion, so any positive suggestions would be appreciated.  Also, if you have the time and desire, PM Chris Anderson about joining the dev team.

My brother and I started, a small company focused on helping people get the best transmitter for your money. Although we're biased, we strongly believe the 9x transmitter is fantastic for UAVs, airplanes, quads, sailplanes and helis. It's what we use (along with all of our friends and customers).

It's the open source firmware that is the key. The teams behind er9x, Gruvin and Open9x enable the 9x to compete with transmitters that cost $500 or more.

For anyone in the market for a new radio...

We stock the FS-TH9x (9B) transmitter as well as a 9x Upgrade Kit that includes the latest SmartieParts rev 2.2 solder less programmer, a backlight, upgraded thumb sticks, shrink tube to color code your switches and a neck strap. The upgrade kit makes modding your 9x really easy. The only tool required is a phillips screw driver.

Additionally, for 9x owners who want to add better range, failsafe and telemetry, we stock the FrSKY 2.4ghz TX module and associated receivers. The TX module plugs into the JR-style socket on the back of your 9x. It's plug-and-play. No additional configuration is required (and it works with the factory or open source firmware).

Checks us out at We're available for any questions (regardless if you buy from us or not).

Good luck building your UAV!


Finally are they working together?

I have the same doubt...

I tested it, it works!

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