Handy Reference Information - RC Groups
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May 16, 2008, 02:31 PM
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Handy Reference Information

How to set up a basic "throttle kill" switch mix for the Futaba T7C (7C) Radio

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Description: The Futaba T7C (7C) Radio.

Application: this mix is for Electric Aircraft use.

PRINT: See the PDF file available below in the "Files" section for download.

Please - always do programming and testing without a prop mounted to the motor!

On the 7C, the throttle channel is assigned to channel 3. For this example, the throttle kill switch will be set on switch "A". Switch "A" will act upon the throttle stick. Switch "A" in the "down" position is throttle stick "kill". Switch "A" in the "up" position is throttle stick active.

Ready the radio: Move switch "A" to the "down" position. Set your throttle trim to zero.

Program the radio: Go to "P-MIX3" on the advanced menu. Press the dial, you will see the first P-MIX3 screen. Press the down arrow key until you see the second screen (yes, you start programming with the second screen instead of the first).

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Description: Futaba 7C Radio - Screen two

Scroll down to return to the first screen. Put throttle stick in the fully off position.

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Description: Futaba 7C Radio - Screen one

Select OFS > SET, then press and HOLD the dial until the radio makes a confirmation beep.

Then set, RT > to -100% (minus 100 percent).

Press the "END" button to return to the main screen and thoroughly test throttle channel functions. The throttle channel should not respond when switch "A" is in the down position. You should have full throttle control when switch "A" is in the up position. You can of course, assign any available switch to the throttle cut mix.

Note: Do not use trim settings on the throttle channel. This basic mix cannot disable trim.


This section contains information that is handy for building. Nice for posting on your toolbox or workbench.

Drill Chart

showing metric, numerical, alpha (letter), and SAE sizes with decimal equivalents from Drill size 80 to 1 inch. This is better than the usual "listing" you find on the internet as it is condensed onto one letter-size page. VERY handy for finding out the drill bit needed when you know the decimal measurement.

See below for the download.

Millimeters Inches Designation
.3429mm .0135"
.3683mm .0145"
.3969mm .015625" 1/64"


Assan Adjustable Retract Gear and Door sequencer w/Display Manual

In actual understandable English! This is my version of the manual for the sequencer. The Assan Adjustable Retract Gear & Door sequencer w/Display is available at HobbyKing, and it is item number 11258, PRODUCT ID: HGDS-1. It is a simple sequencer, but it does the job. Would be nice to have a servo slo-down for the doors, but at this price...

See below for the download

Futaba - HiTec Servo Rotation Notes.

With a Futaba 7C Radio Transmitter and Futaba R617FS Receiver connected to a HiTec HS-5645MG Programmable Digital Servo (default programming), maximum rotation possible is 80.

so, for the given 7C settings:

D/R = 100%, Endpoint = 100%: rotation = 80
D/R = 140%, Endpoint = 100%: rotation = 113
D/R = 140%, Endpoint = 140%: rotation = 117.5

D/R is "Dual-Rate" which commonly, but incorrectly refers to "travel".

It is possible to program HiTec servo's for up to 180 rotation. Radio settings are scaled up or down accordingly. If the SERVO is programmed for 180 rotation, radio maximum settings (140%, 140%) will allow 180 rotation. If the SERVO is programmed for 60 rotation, radio maximum settings (140%, 140%) will allow 60 rotation.


Tacon 60 Motor and Prop test Data.

Here is some data collected by direct measurement for a project. Notice that because of the very large capacity battery, there is little voltage sag, so the power readings for the prop size are going to be very much larger then if you were using a 6S 3200 mAh battery, for example.

Interestingly, the E-flite Power 60 (400kV) [which is similar to the Tacon 60], has the following specs listed for it on its website: 6-10 lb plane, up to 1700 Watts, 5-7S, 51a+ continuous current, 65A for 15 seconds.
With 6S, APC 15X10E prop; 56A, 1195W, 7375 rpm.
With 6S, APC 16X8E prop; 50A, 1060W, 6975 rpm.

Quite a difference. I would keep the Tacon 60 in the 50 -60A current range so as not to overheat the motor, until at least, I have more data regarding motor temp in actual flight conditions.

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Description: Tacon 60 Brushless Motor Propeller Test Data. APC and Xoar props. 6S, 10,000 mAh battery, 80A Plush ESC.(click to enlarge image)


E-Flite 770kV Motor and Prop test Data.

Data for the E-flite 32 on the web:

Continuous Current: 41 - 50A
Idle Current (Io): 2.40A @ 10V
Maximum Burst Current: 60A (15 sec)
Overall Diameter: 42mm (1.70 in)
Overall Length: 50mm (1.90 in)
RPM/Volt (Kv): 770
Recommended Prop Range: 11x7 to 14x10
Shaft Diameter: 5mm (.20 in)
Speed Control: 60A brushless
Voltage: 1216.8v (3S-4S)
Weight: 200 g (7.0 oz)

My Measured Data:
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Description: E-Flite 32 770kV Brushless Motor Propeller Test Data. APC Thin Electric props. 4S, 8000 mAh battery, 75A Castle Ice2 ESC.(click to enlarge image)

Note my E-Flite 32e Mustang uses this power plant and my measurements were:

Wide Open Throttle (WOT): with 4S GForce 3300 mAh 30C Lipo:
With APC 13x6.5EP: 14.3 V, 47.6 A, 695W (battery 16.5 V initially)

Last edited by nioa; Aug 04, 2014 at 05:47 PM. Reason: Update
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