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Hi There,

I would like to share with you my yesterday’s tests and hopefully share some views about range test safety.

I have a new Boomerang XL jet in which I have installed:

1- An old type Smart Fly power expander.

2- A smart fly super regulator set at 6.0 v.

3- 2 lithium ion 2600 mA batteries

4- TX Futaba 9Z WCII . Futaba 149 DP RX. In 40 Mhz frequency.

5- Antenna wire cut off lenght of whip antena and whip antenna installed externally front of canopy.

6- Brand new 6 x Hitec 5985 servos (2 Ail, 2 flaps and 2 rudders)

7- Brand new 2 x Hitec 5955 servos (2 elevators).


Range test.

I performed the range test, at 70 meters away from the plane and when I have first portion of TX antenna out, I get a good signal if I am standing up but intermittent signal if I lower TX on the ground.

Is this normal bearing in mind distance used to perform test, also knowing that same test at about 30 meters is working properly even with transmitter on the floor.

I definitely wouldn't want to take unnecessary risks anf fly this jet if above test doesn't sound ok.

Appreciate your experience and views as regards to standard range tests and acceptable distances to perform same.

Thanks. Regards.
Dany

swissflyer

is always difficult to say if is good or not..
for sure you have to do the same with turbine running, and see if there are differences..
and look at what the TX manual say...how much should you get..


for compaire..
i did saturday similar test, using same RX as you, but a fx40 as tx.
the model was about 40 cm from floor.
got 200 meters with antenna collapsed...and i didn't walk more...

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Swissflyer,

Thanks for your feedback. Reason i am asking is that's the first time i use a power expander in my setup and i don't feel quite comfortable with the result of this range test.
Also i did not turbine due to sudden weather deterioration.

Hoping to have more views on the subject.
Regards.
Dany

captainjacobs

I have approximately the same results with same TX and RX in my F18... no problem in flight.

Heatseeker_Hill

they do reccomend tht you never fly with your tx ariel facing down

ViperOneNL

Hi,

Normally the base rule is: all antenna sections colapsed so you only have one section, then 25 meters is enough with an running engine.

With your figures, I would not worry, but just to feel save you can do the following tests:

1) stand at 70 meters with the turbine running and let somebody turn the plane in all four wind directions, afterwars check the ECU fo failsave conditions!

2) repeat the same test with a "normal" 4 cell receiver pack, just to be sure that your powerbox is not intermitting!

all good, fly and have fun.

My 2 cents.

Cheers,

Mick.

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captainjacobs, Heatseeker_Hill, Mick

Thank for your input.

Mick, Do you suggest i run tests at 25 meters standing up or having TX on the ground?
Will also try the 70 meteres test as suggested.

Thanks. Regards.
Dany

KC36330

the way you should do a range check......... [link=http://www.jrradios.com/Articles/Article.aspx?ArticleID=1079&Page=4]CLICK HERE[/link]

doing it the above linked way i run out of field before it goes into fail safe.

squirt!

I have the same radio, although on 72mhz...Ive never had over 40 meters.

squirt!

I have the same radio, although on 72mhz...Ive never had over 40 meters.

bigplumbs

70 meters is a very good range test with the atenna down..........30 - 40 meters is acceptable

Dennis

www.densplanes.co.uk

Molar mender

Dany

Everything sounds good to me. I have virtually the same setup in my Boomer XL II as you do with a couple of exceptions. First, instead of the Smart Fly expander I am using the ElectroDynamics Pow'r Bus Pro to optically isolate all the servos which are driven by a separate 6v battery using a Duralite voltage regulater and the receiver on a separate 4.8v battery. The second and third I will relate, later.

Your range check is perfectly normal if your airframe is on the ground and you are holding the TX waist high or more. If your airframe is off the ground at one meter (3 ft) and you are holding the TX with a 3 cm (7 inches) length antenna extended you will can get up to 85 meters (250 ft) by virtue of an unobstructed wave propagation.

Now a short primer on wave propagation. If you lay your TX on the ground you are attenuating the signal which will drop your range considerably. If you visualize your antenna as a stick with a donut on it, and that donut is an ever expanding 360 degree donut which can bounce off the ground, you can see why the signal does not go anywhere when you lay your TX on the ground. It does not allow the signal to function normally (you are keeping the donut from expanding to reach your airframe). Also, if you point your antenna at your airframe, all you are doing is pointing the donut hole, or no signal, (a null node in radio terms) at your aircraft. The best orientation of antenna to airframe is perpendicular at all times.

Second exception is the flap servos. I have always used analog servos on my airframes due to the potential of higher current draw in the deployed position. I have a digital servo meter that displays the amp draw under load and have checked all the flying surfaces. The main reason I check is the Duralite voltage regulator I have is only rated for seven amps load. If I have 6 digital servos, each pulling an amp under load and hit the flaps, I may swamp the system. I am using the Hitec 755MG metal gear (not Karbonite) servos for my flaps. Currently my entire system only draws 2.5amps under full load.

Third exception is my battery capacity. I currently have 94 flights on my Boomer XL II this year and the average flight totals approx 12 minutes, which includes the start-up, taxi out, flight (7-8 min) taxi back and shut down. The servo batteries each average 400mAh draw down per flight, Rx batteries each about 300mAh draw down (rx also has retract, brake and nose gear steering servos attached) and ECU averages can be as high as 500mAh draw down if I use the auto cooling on the turbine (I use external cooling to save the battery and starter O-ring). I am using 2 x 4600mAh NiMH for the 6v servo battery, 2 x 2400mAh NiMH for the 4.8v receiver batteries and a single 3600mAh NiMH for my turbine ECU battery. This allows for 4 flights between charges and draws the battery capacity down to only 50% or less which allows for a reasonable margin of safety.

I love the Big Boomer. A few photos of my Boomer with modified somewhat animated cockpit. Lots of fun with smoke and of course crow for landing. I know you will enjoy yours.

siclick33

Futaba range test is detailed here

http://www.futabarc.com/faq/faq-q331.html

Futaba suggest 100ft (30M) minimum and no more than 10% drop with engine running.

You are correctly testing the 9Z with the first portion of the antenna out. This is different from other radios as the 9Z case shields the antenna when it is fully retracted.

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Thank you all for your various and precious inputs.

Molar mender,

Special thanks to you for your detailed and informative explanations. I would like to tell you that i had also a mishap on one of my flap servos while running some tests on the field.
I saw white smoke coming out of a flap servo HS 5985 (brand new Hitec servos). System was shut down immediately and when I dismantled said servo, it was completely jammed and lower case was burned. Knowing that this was the first pre flight and I had run extensive tests on all servos back in my workshop with no issues at all.

a)Would it be possible somehow, that smart fly/battery setup would be at fault and might have caused this problem?
b)Knowing that I ran my system at 6.0V. would this voltage be excessive on the Hitec servos?
c)What can i do to avoid same thing of happening to other servos on this plane?

Thanks again for all info.
Best regards.
Dany

Molar mender

Dany

You have a very nice clean set up. I will try to answer your questions.

a)Would it be possible somehow, that smart fly/battery setup would be at fault and might have caused this problem?
I don't think it is the SmartFly setup as it would have happened to other servos if it was. If you have a multimeter (voltmeter) you could check both input and output voltages of the SmartFly board to verify regulated voltage. Your batteries when fully charged will put out more than 7v (even up to 8v) and should show that voltage before the board. Your board output voltage should show 6v if your regulator is working properly.


b)Knowing that I ran my system at 6.0V. would this voltage be excessive on the Hitec servos?
If the outside of the Hitec servo box shows the servo will operate at dual voltages, there should not be a problem. The servos that you said you were using should all work okay at 6v. Even though I use analog servos on my flaps, they still use 6v for power.


c)What can i do to avoid same thing of happening to other servos on this plane?
I would guess that somehow your flap got bumped while being transported/moved and damaged the gear train which caused the jam.

I use the Hitec HFP-10 servo programmer before I install my servos to reset the factory values and to check all the settings, mid point, end point and deadband. It also allows me to test the Rx voltage. Once the servo is in the aircraft I use the programmer to operate the servo instead of the Tx/Rx to verify its operating position and correct linkage setup. If everything is correct, then I hook up the servo lead to the Rx an make the final adjustments on the Tx. It is the best way I know of to prevent servo jam on the initial install.

Hope that helps.

Roy

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Roy,

Thanks again for your feedback.

actually , i also used the Hitec HFP-10 servo programmer to test/ adjust the Hitec servos on board the XL also to avoid using matchboxes.

On the other hand, I have an on board voltmeter plugged in power expander and showing a steady 6.0 V (which i have actually reduced to 5.5 V just in case....)
As for the input voltage i have tested same on several occasion using a Fromeco 8 ball tester and i have a reading of about 8 V. under 1.5 A load.

Quote:
It also allows me to test the Rx voltage. Once the servo is in the aircraft I use the programmer to operate the servo instead of the Tx/Rx to verify its operating position and correct linkage setup. If everything is correct, then I hook up the servo lead to the Rx an make the final adjustments on the Tx. It is the best way I know of to prevent servo jam on the initial install.

Unquote

Could you please explain how to "test RX voltage" with programer?
Finally, if servo would buzz while under load would this create a problem leading to jamming etc...?

Appreciate very much your help in this respect.

Best regards.
Dany

Molar mender

Dany

That's great that you have the programmer; you are ahead of the game. And it sounds like you are aware of the voltages your system is putting out and know your system. Good man. I have seen quite a few regular fellow flyers at the local flying field that have no idea what is going on with their systems. Jet guys seem to be one step up just because of the investment involved.

Digital servos have a tendency to buzz a little louder than analogs. But the buzz can be minimized or made to completely go away if the flying surface does not bind. Every effort needs to be taken to insure the flying surface is free and does not bind. I use the Hanger 9 Digital Servo and Receiver Current meter (set to Amps) to check how much current is being drawn by each servo. This will check to see if the flying surface is binding and putting unnecessary load on the servo.

Unfortunately, you may have had a bad servo. It's a good thing yours locked up on the ground. I have only seen one other Hitec digital servo lock up like yours and it was on the third flight of a Reaction-54. It happened to be the elevator servo and it locked up while the Reaction was in the air. The pilot lost the aircraft. The servo was also taken apart and it was found to be jammed. I have had a couple of Futaba servos go bad (one resulted in a lost airframe), so I don't think it is manufacturer specific. It just happens. ( I have a brand new JR radio to try in my next jet, first JR radio I have ever owned or used)

To check your Rx voltage going to the servo by using the Hitec programmer. First plug in the programmer to the receiver channel you wish to check. Turn on the programmer and go to the menu -->Measure Voltage. Now turn on the Tx and then the Rx. Press the input button on the programmer and the voltage should show. When you push the M button you should see the actual voltage. Since you are hooked up to a common power bus on either your receiver or your SmartFly, you should see the voltage fluctuate when you move the other servos. Just press the input button or turn off the programmer to exit.

So it sounds like you are doing everything right and you are taking all the precautions. Let us know how your maiden flights go.

Roy

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Roy,

Thanks again very much for your detailed explanations.
For your guidance i think i have some some servos that are binding somehow on a couple of surface which i will try to take care off.
Going back to test described above, i don't quite understand how you can make servo move to extreme positions with TX if the programer is connected between RX and servo.
Should i turn the knob manually and check voltage? positively, in this case, when you turn the knob you will surely outrun the maximum deflection set on the TX and actually you may not be able to determine this point (if you understand what i mean)

On the other hand, i have tried yesterday to connect the Hitec programer to nose wheel servo and following reading was found:
1- power expander output voltage (c-volt voltmeter) reading 5.48 Volts
2- Programer connected to power expander channel 4 and nose gear servo connected to power expander giving a voltage reading of 5.64 V when M button is pushed voltage fluctuates 0.02 volts.

Naturally i did not move the knob to check voltage at extremities of movement.

Thanks advising meaning of above readings and ultimately how to proceed efficiently.

Best regards.
Dany

Molar mender

Dany

Glad I can help.

The Tx is disabled by the Servo programmer when it is plugged into the specific servo circuit. You will need to turn the knob to actuate the surface you are checking. Yes you can over run the Tx setting, but you can mark the actual distance the surface moves to get the actual voltage drop required to move the surface to that distance. When you initially power up the Servo programmer and press the input you should see the resting voltage of the servo. Actuate the servo with the knob in both directions and you should see a voltage drop and it will hold at the last lowest value. When you press the M button it should go back and read the current battery voltage output. The manual does not explain it very well.

Now if you move the other surfaces with the Tx while the Servo programmer is still plugged into the Rx, you will see more of a voltage drop because all the servos are being driven by the same power bus as the one you are checking. I did the same test on my new Reaction nose gear and rudder and found the resting voltage was 5.31v (I am running 4.8v battery). By turning the knob to make the rudder turn to the outermost position I have set in my Tx, it dropped the voltage to 5.26v. I then hit the M button and the reading returned to 5.32v. Then I started moving all the control surfaces with my transmitter for about 10 seconds and the voltage drop went to 4.76v. I hit the M button and the the actual voltage read 5.28v. It shows me that enough current is being expended to run the servos to drop the voltage about 0.6v. Then when you hit the M button to go back to the actual voltage, you should see that the battery has been discharged because you used that much energy to do that amount of work in that 10 seconds.

You can actually move the knob to deflect the surface to extremes. It will show that if your surface is binding and drawing a lot of amps, then you will get a big voltage drop.

Hope that explains what is going on.

Roy

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Roy,

I appreciate very much the way you are explicitely providing details of the various steps to do to test voltage in the system.

I will try to measure as per your explanation and revert with results.
On the other hand, when i initially did the first set up installed all servos i took care (as i usually do) not to stall any servo when reaching extreem position, but nevertheless, buzzing sound of digital servo would increase when reaching end positions (in some cases) but obviously did not check voltage drop to check severness of situation.
Also, I have notice that if i want buzzing sound to stop completely, then i would loose some throw which will most likely compromise the overall flight characteristics of the jet (in my opinion of course)

I always like to have more then less throws case i need same for first flight. I can still use D/R if needed but would not be able to increase deflections during flight.

Thanks again.
Dany