Admiral RX600SP 6 axis stabilizer from MotionRC - RC Groups
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Oct 16, 2017, 05:52 AM
ancora imparo
jj604's Avatar

Admiral RX600SP 6 axis stabilizer from MotionRC

We maintain the Lemon Instruction and Stabilizer threads on RCGroups (although we are not connected with Lemon in any way). Accordingly we have extensive knowledge of the Lemon Stabilizer and StabilizerPLUS. We now have a fair bit of experience flying with the Admiral RX600SP stabilized receiver from Motion RC which is a variant of the Lemon StabilizerPLUS.

We have flown examples in several different models and feel we have a good basis for evaluating the performance of this new stabilizer.

John (JJ604) and Nigel (Daedalus66)


In terms of its hardware, the Admiral is manufactured by Lemon RX and is identical to the Lemon LM0044 StabilizerPLUS receiver. Physically, only the label is different; Admiral has simplified it to make it easier to follow.
Some of the information has been moved to a new label on the back of the case. This arrangement makes it easier to read without a magnifier if your eyesight is less than stellar – but once you have mounted the stab with the supplied double sided tape you can no longer see the instructions for the DIP switch settings.
The real differences are entirely in the revised firmware, which was developed by Motion RC. To quote from the website, “Motion RC has drastically simplified the stabilizer programming functions and gyro functionality.”
The inevitable result of this is that the Admiral is easier to use but much less flexible in application compared to the Lemon StabPLUS. Many of the Lemon’s adjustment possibilities are omitted from the Admiral in order to make it as close as possible to “plug and play”.
On the other hand, the Admiral has an ingenious feature that allows an electric retractable landing gear setup to be used on channel 5 (Gear) while still supporting switching of stabilization mode; by contrast, the Lemon StabPLUS can only make channel 5 available by use of its Always-ON function.
So in the Admiral we have a very different unit from the Lemon on which it’s based. Our purpose here is not to judge which stabilizer is “better” but to help potential purchasers understand the differences in relation to their own needs and make their own decision.


In a number of important ways, the Admiral functions in the same manner as the Lemon StabPLUS on which it is based:
• It is compatible with the Spektrum DSMX protocol (and DSM2 with certain reservations).
• It has dual diversity antennas and does not provide for (or need) a satellite receiver.
• It uses the standard Spektrum TAERGAux1 channel order (though it uses the Gear channel differently from Lemon).
• Binding is done in the normal way (and as with Lemon, may not work with some RF modules).
• The Admiral supports both no-pulse and preset failsafe, like the StabPLUS.
• As with Lemon, pots on the receiver adjust gain for Aileron, Elevator and Rudder channels.
• Switches J1, J2 and J3 set the direction of stabilization response on the three channels.
• Switches J4, J5 and J6 determine stabilizer configuration (normal, elevon, V-tail, dual aileron).
Physically, the Admiral is identical to the dual diversity antenna version of the Lemon StabPLUS except for the label.


In other respects, the Admiral differs significantly from the Lemon StabPLUS. Most importantly, if it is used as intended, the Autolevel function is essentially eliminated and replaced by Panic Recovery on a momentary switch. When invoked, this quickly returns the model to more or less upright and level flight. This obviates the need for a Level Reset capability as part of initialization and greatly simplifies setup.
The Admiral supports three stabilization modes.

• “Stability mode” is the normal state (“Gyro mode” in Lemon terms). This provides rate stabilization (similar to Spektrum’s AS3X©), which helps to smooth out flight by correcting for wind turbulence and other disturbances. It does not automatically return the model to level flight.
• The second mode, “Stabilization Plus”, provides panic recovery action (using the autolevel capability of the Lemon hardware), activated by pressing a momentary switch or button.
• The third mode is simply Stabilization OFF.

The Admiral can be switched in flight between any two of these three modes, previously selected. The default pair of modes is Stability/Stabilization Plus. Other combinations are Stability/OFF and Stability Plus/OFF, but these are less likely to be used. Changing the chosen combination is done by pressing a button on the receiver.
Selection in flight between the two chosen modes is enabled by pressing a momentary switch (the bind/trainer button on a Spektrum transmitter), programmed to change the end point of channel 5 by a small amount.

Here’s how mode selection works to allow the use of channel 5 for both retract gear and mode change. Electric retracts are switched between up and down positions when the value of the control pulse goes from substantially negative to substantially positive, or vice versa. The range required to activate the retracts is often described as ̵100% to 100%, but the actual values are not critical. The retracts do not care whether the actual percentage value is 95, 100 or 105. Thus it is possible for a 5% change in either the ̵100% or 100% value to be detected by the Admiral as a signal to switch the stabilization mode without triggering a change in the retract position. (This is only possible with electric retracts as a normal servo on channel 5 will respond to the 5% change.)

The Admiral’s method of operation makes the Always-ON function used by the Lemon StabPLUS unnecessary.
The Admiral can be set to basic or advanced rate for the Recovery mode (like the Lemon StabPLUS). We used the advanced setting.
The Admiral does not support Master Gain (which is provided on channel 8 by the Lemon StabPLUS).
The Admiral does not support Level Reset (something done by toggling during initialization for the Lemon). This means that there is no means of adjusting the level attitude other than changing the mounting angle of the receiver (more on this later). Moreover, the Admiral can only be mounted upright with connectors to the rear.
There no provision for Trim Reset, but this is not significant in light of how the Admiral is intended to be used.
Initialization of the Admiral is much more rapid than with the Lemon StabPLUS, as might be expected.

How well does it work?

In Stability mode (corresponding to Lemon Gyro mode or Spektrum AS3X), the Admiral provides very effective rate stabilization, comparable with that provided by Lemon stabilizers.
Installation of the Admiral is very easy provided it can be mounted with the pins to the rear, upright and level from side to side; other orientations are not supported. Double sided tape is provided for this purpose. In most cases, leaving the gain pots at their default 12 o’clock settings will provide satisfactory operation, but we found that for one of our test models, aileron gain needed to be turned down slightly to avoid mild oscillation. For several of the models, elevator and rudder gain could be turned all the way up to enhance stabilization without inducing oscillation.
Panic Recovery uses Stability Plus mode to restore the model to level flight when the momentary switch (bind button) is pressed. It does an excellent job of quickly rolling the model upright from any attitude, but it sometimes leaves the model in a steep dive which may require the pilot to use up elevator for recovery to level flight.
To achieve rapid fully automatic recovery, we found the Admiral receiver needs to be mounted not flat on the floor but nose down at an angle of 5 to 10 degrees. If this is done, when the button is pushed, the model snaps to level on both axes quickly and with great reliability.
The Admiral is not intended to be operated in prolonged Stability Plus mode, as the necessary provisions for adjustment (level reset and trim reset) are not available in its simplified firmware. Consequently, it does not attempt to emulate the range of functions of other six-axis stabilizers.
The Admiral can be set up to fly for extended periods in Autolevel mode by substituting a two- position toggle switch for the button or momentary switch. However, the lack of any means to reset the default attitude makes this of very limited value. Anyone intending to fly in Autolevel mode (other than for momentary panic recovery) should look instead to more capable six-axis stabilizers such as the LemonPLUS.
Before flying it is vital to ensure that stabilizer action works in the correct direction on each of the three axes, since in the default configuration no means is available to turn off the Admiral in flight. Reversed stabilization creates a very scary situation that will likely lead to a crash! A beginner would normally have little hope of managing a plane with reversed stabilization action. We would like to see this point emphasized in the Quick Start Guide.
Those who have an eight or more channel transmitter should note that the Admiral does not support Master Gain control, a very useful feature available on both the regular Lemon Stabilizer and the PLUS.

Transmitter Considerations

To perform as intended, with a functioning “panic button”, the Admiral RX600SP Stabilizer requires the use of a transmitter that can be programmed to use the bind switch or button in a mix that controls the output of channel 5. This appears to rule out the old DX6i and original DX7, as well as the JR 9303 and 9503. The Quick Start Guide does not mention this explicitly, but simply states that a DSMX transmitter is required. In other words, it implies that older generation Spektrum transmitters are not suitable.
In fact, the Admiral can be used with a wide range of DSM2 and/or DSMX-compatible transmitters, but with limitations in some cases:

• With a DX8G1, DX7s or any recent (G2 or G3) programmable Spektrum transmitter, the Admiral can be set up to be fully functional.
• With a DX6i, original DX7, JR 9303, etc., it will function as a rate stabilizer, but cannot also support retract gear or any other function on channel 5. Stabilizer mode is controllable by the Gear switch if the travel is set to ̵100% and 105%, thus providing a somewhat awkward but workable panic recovery function.
• With a Taranis, Devo, Turnigy 9X/9XR/9XR Pro or other such non-Spektrum programmable transmitter, the key question is the compatibility of the RF module, as generally the transmitter’s programming capability will be amply flexible. We have found only “hack” modules from a Spektrum transmitter (DX4e, DX5e, DX6i) or those using the Multi-Protocol (such as the iRange 4in1) to be usable.

Bottom Line

The Admiral RX600SP will appeal to people looking for an easy-to-set up rate stabilizer that also provides an effective panic recovery function. If mounted a few degrees nose-down, as explained above, it will reliably bring the aircraft back to level flight from any attitude when the button is pressed, even at very low altitude (somewhat like a SAFE© model in Experienced mode).
The other noteworthy feature of the Admiral Stab is that it permits switching mode while retaining full use of channel 5 (Gear) for electric retracts. The popular configuration of electric retract gear on channel 5 and flaps on channel 6 is thus supported.
It should be noted that while the setup of the Admiral is much simplified, it is not foolproof. It is important that it sits level in the roll axis and that cables or other parts do not press down on it and disturb it. Most importantly, before making a test flight, great care must be taken to verify that stabilization on each channel works in the correct direction.

UPDATE: I have added this post as a pdf for Tapatalk users and anyone who prefers to print it out.

Also MotionRC's Quick Start Guide is here.
Last edited by jj604; Oct 16, 2017 at 09:02 PM.
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Oct 16, 2017, 06:56 PM
60 years of RC flying
Daedalus66's Avatar

Admiral RX600SP 6 axis stabilizer from MotionRC

Viewing the above post in Tapatalk I see that only the last few paragraphs are displayed. In Web View, however, the whole post, which is quite long, can be seen.
To see Web View in Tapatalk, touch the post and select ďMoreĒ.
Oct 16, 2017, 09:04 PM
ancora imparo
jj604's Avatar
I have added the contents of Post#1 as an attached file in the post as a .pdf for Tapatalkers and also a download link for MotionRC's Quick Start Guide for this receiver.

Oct 18, 2017, 10:20 AM
Registered User
Too bad they couldn't/didn't retain the remote master gain.

Gene K
Oct 18, 2017, 11:31 AM
Fire Marshall Bill
I fear Motion has taken the wrong tack on this. The Lemon + needs improvement, not further simplification. My opinion. Time will tell.....
Oct 18, 2017, 05:40 PM
60 years of RC flying
Daedalus66's Avatar
The Admiral uses Lemon StabPLUS hardware but goes in a totally different direction with its programming. They are not trying to improve the Lemon but to offer an alternative type of stabilizer.
Itís not a question of whether they have ďtaken the wrong tackĒ but how many customers will like the tack they have taken.
As we said in the review, the Admiral is easy to install, does a pretty good job of providing a panic recovery function, and solves the problem of using channel 5 (Gear) for retracts.
Oct 30, 2017, 12:10 PM
Registered User
Hello Gene,

MotionRC said the remote gain is just too much for beginner. I agree at this at some point and since they said the best selling Spetkrum transmitters are DX6.

Best Regards,

Lemon Rx Officer

Originally Posted by speedy01
Too bad they couldn't/didn't retain the remote master gain.

Gene K
Oct 30, 2017, 05:55 PM
Registered User
Originally Posted by fmak2
MotionRC said the remote gain is just too much for beginner.

That's funny! I give folks bright enough to get into RC more credit than that!!

Gene K
Oct 30, 2017, 05:58 PM
Registered User
Originally Posted by fmak2
... the best selling Spetkrum transmitters are DX6.
My friend has a DX8 -- could someone tell him the menu settings (or a link), please? Different than on my DX9.

Gene K
Oct 30, 2017, 07:29 PM
60 years of RC flying
Daedalus66's Avatar

Admiral RX600SP 6 axis stabilizer from MotionRC

I suggest he look at the video on the Motion RC website, which provides a fair bit of detail on how to set up the Admiral Stab.
Written instructions are also available on the same page.
Also, he may want to read our review at the beginning of the thread.
How you set it up depends on how you want to use it. This is discussed in the video.
The only thing I would warn about is that the instructions gloss over the critical importance of setting switches 1, 2 and 3 for correct direction of stabilization action on each of the three channels. This really matters!
Oct 30, 2017, 07:56 PM
ancora imparo
jj604's Avatar

DX8 Gen1 and the Admiral

Here's how to set up a DX8 Gen1

Set Gear Travel in the SERVO Menu to 100% in both directions
Set Aux2 Travel in the SERVO Menu to 100% in both directions

In SWITCH SELECT, assign the Trainer button to Aux2
In SWITCH SELECT, assign the Gear switch to Gear
All others Inhibited

Set up MIX1 as

AX2 -> GER
Rate 0%, 5%
Offset 0%

The Gear output will then operate normally for electric retracts and the Trainer button will invoke Panic self levelling mode. Check on the monitor screen what the gear channel does when you press the button. It should move from +/-100% to 95% or -105%. The +/- signs don't matter as long as the number changes from 100 to 95 or 105.

You may have to reverse the Gear direction of course but this should not affect the Panic mode operation.

Oct 31, 2017, 08:50 AM
Registered User
Originally Posted by jj604
Here's how to set up a DX8 Gen1 ... .
Perfect (as usual), John -- thanks. I passed the info to him and I'll confirm he's up and running.


He had read the material (and now viewed the video), but the orientation is for the DX6 transmitter menu, and the DX8 is different -- for example, there is no "I" selection in the Mix menu on the DX8 . Jon set it all straight by assigning the Trainer to Aux 2.

Thanks to both of you, again.

Gene K
Oct 31, 2017, 09:43 AM
60 years of RC flying
Daedalus66's Avatar

Admiral RX600SP 6 axis stabilizer from MotionRC

I donít have a DX8, just a DX8G2. Thatís why I left it to John to deal with that aspect of your question. 😊
Itís worth noting that the video suggests setting the stabilization option to STAB/OFF (rather than STAB/RECOVER), using a two-position switch (rather than the Bind button). Thatís in fact how I would use the Admiral Stab. This, of course, means forgoing the panic recovery function and using just rate stabilization. Itís a good way to go for a pilot whoís past the disorientation stage.
Using the Admiral this way means you have full use of channel 5 for retract gear and can still turn the Stab on and off in flight (by contrast with the regular Lemon Stab). This is particularly useful for someone with a DX6 who wants retracts and Flap.
Nov 12, 2017, 11:07 PM
Registered User
I assume you could put the auto level on a switch as well instead of a button like Motion shows? I'd like to have autolevel with a slight up elevator for hand launching a delta.
Nov 13, 2017, 12:26 AM
ancora imparo
jj604's Avatar
Depending on your transmitter mixing capability you can not only have it on a switch you could have both.

For a switch just make sure the two positions are -105% and 100%.

Normal is -100% or 100%
Autolevel is +/-5% added to that value.

So you could then add a mix if you wanted to controlled by the button to add 5%. If you are in normal mode on the switch (100%) this will give you autolevel (105%). If you were in Autolevel (-105%) it will give you normal (100%)

It was very simple with my Taranis and OpenTX using the 4in1 Multimodule. Most Spektrum Tx can probably do this as well. From memory on the old Gen1 DX8 you have to use a spare channel controlled by the button and mix it to channel 5.


Originally Posted by Ekibiogami
I assume you could put the auto level on a switch as well instead of a button like Motion shows? I'd like to have autolevel with a slight up elevator for hand launching a delta.

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