Author Topic: DENTON SWAP MEET AUGUST 4  (Read 501 times)

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Offline Joystick

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Re: DENTON SWAP MEET AUGUST 4
« Reply #15 on: August 07, 2018, 10:01:44 pm »
If I understand correctly....they are not advocating to re-bind before each flight

Rebind for the area or field you are set to fly at....if different from last bind.

-Paul H Lange

Logic would dictate that if they recommend that you rebind due to being at a different location, the only reason would be to account for the electrical differences from one bind to the next. The implication, to me, is that if you don't rebind, then the system may not be able to control the plane. Any changes in the electrical differences after that binding would require another bind session, or loss of control may result.

My issue is the language used as the reason for the rebind. I agree that the binding "optimizes itself based on current circumstances", and that it "may set up differently at the field as opposed to binding at a different location." None of these should cause any control problems.

My problem is this: "Doing so may help the radio system to operate per environment better." How do they define better? I would hope that "better" would only be fewer milliseconds to recover from a lost signal which should NOT result in loss of control of the plane.



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Offline Lane C.

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Re: DENTON SWAP MEET AUGUST 4
« Reply #16 on: August 07, 2018, 11:45:01 pm »
As I see it, it's not much trouble to rebind a SPEKTRUM before EVERY flight if you wanted. That's why I mentioned using a servo extension from the Rx to somewhere outside the aircraft (or long enough to allow you to pull the extension outside the aircraft and tuck it back inside with Velcro) so you don't have to take the wing off to get to the Rx and then rebind. THAT would be a pain in the rear end.  But, simply rebinding with a Spektrum isn't a big deal in itself. And, even if you make a trim change during a flight, that would possibly be a good reason to rebind. I have also learned that you cannot check your batteries too many times at the field. And, maybe the same is true for rebinding. After all, most of us only fly 2 or 3 times per  trip to the field anyway. Except for BARRY! He flies at least 6 times, maybe 7 times per outing, using perhaps two or three separate planes! Yikes! But that's why he's the test pilot - lots of stick time!

Offline Joystick

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Re: DENTON SWAP MEET AUGUST 4
« Reply #17 on: August 08, 2018, 07:02:53 am »
My point is that rebinding should not be a requirement for a safe flight.

We use a similar system on full sized aircraft and over time the system may work better or worse depending on the local electrical differences, but we don't rebind the system unless it fails. In this case, "better" just means fewer data bits are dropped in a given time, rebinding would only be a temporary "fix" due to changes in the electrical environment. Making adjustments such as trim or switch reassignments should not have any affect on the RF section.

To make the system work "better" or "faster", busy, or noisy frequencies could be stored in memory so they could be skipped. I'm not sure that is how the Spektrum radio works. There are some major problems with that design. It would be helpful to have more info on what they actually do with binding.

Some info on how the hopping is determined can be found here: https://www.eetimes.com/document.asp?doc_id=1271899
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Offline Paul Lange

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The way I feel about Spread Spectrum is partly summed up by the way it deals with interference.

To the degree of radio interference.....the chances of radio signal control loss recovery should be better on Spread Spectrum than dedicated Frequency RF loss recovery.

Simply stated the radio systems are constantly getting "Hits" so it's mostly a game of repeated recovery and speed of each incident.

I am not sure at all if my maiden was an onboard flight battery power sag.....or radio signal loss.

The only thing I know is......I lost control and regained it.......and we seem to have some degree of confidence that the North East corner of the left handed circuit pattern is more likely to have issues than any other at our field.....and I will proffer it's happening more frequently than I can remember.

Until we some how find out more about that zones gremlins, spacial vortex continuems, solar flares, inner earth Hz burp columns or proximity radio interference blast.......I'll do anything possible that may suppress the losses.....including dances and putting broom straws on water melons to help deflect radio losses!!

-Paul H Lange
Best Regards - Paul H Lange

Offline Joystick

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Re: DENTON SWAP MEET AUGUST 4
« Reply #19 on: August 08, 2018, 09:55:58 pm »
The new radios are much better at preventing interference from other radios, but unfortunately, they are still prone to other interference. That problem will always be with us.

The NE corner gremlins fall into several categories. It is the farthest from our transmitters, so range is a factor for the park receivers, single receiver antenna systems, and low voltage problems due to battery health and servo current draw.. It is also where our planes are slowing down for landing and since angle of attack and speed are hard to judge at that distance, stalls are quite common. It is also where the RF reflections from the steel towers would cause the most interference.

We need to gather more detailed info on what the airplane is actually doing when it is not in control of the operator.

It's a good idea to know what your plane does when it loses the signal from the TX either due to interference or low voltage. Do you have your fail-safe circuit set correctly?

It's also good to know what your plane looks like in a stall during a turn. Check that at 3 mistakes high.

Some people fail to monitor the amount of charge it takes to get the batteries up to full after a flight, or number of flights. That can be very helpful information.

We need more detail on exactly what the planes are doing when they are "out of control" and how long the condition lasts.
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Offline Joystick

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Re: DENTON SWAP MEET AUGUST 4
« Reply #20 on: August 09, 2018, 08:37:36 pm »
Here's what I found out from Spektrum:

Subject: [#ISX-664-21731]: Contact from spektrumrc.com
Hello,
This is not Spektrum policy. Our radios have the model match technology, which means the receivers GUI code is stored in the transmitter. Rebinding shouldn't be necessary unless for some reason your transmitter dropped its bind.

Cody A.
Product Support
Horizon Hobby, LLC



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Offline Paul Lange

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Re: DENTON SWAP MEET AUGUST 4
« Reply #21 on: August 09, 2018, 09:18:08 pm »
Well .....we need to see if Cody is a Russian Spy 1st.

I was really hoping the Re-Bind exercises at the field level would be "some" kind of mediation of monkey madness

Now I am really leary of flying anything worth having in that area.......

Wish we could do some noise sniffing out there.....but if we found something what would we do anyway?  Still I'd like to know.

Gotta be some persons in the DFW area that could help us out

Paul H Lange

Best Regards - Paul H Lange

Offline Joystick

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Re: DENTON SWAP MEET AUGUST 4
« Reply #22 on: August 10, 2018, 07:25:17 am »
I'm still not sure that the problem in the NE corner is due to radio interference.

The radio link seems to be really solid.

The FHSS systems have 79 frequencies to pick from, I don't know how many frequencies that Spektrum uses, probably not all of them due to cost, I suspect it is about 20.

It is also unlikely that they use the adaptive frequency hopping spread spectrum that improves resistance to radio frequency interference by avoiding crowded frequencies in the hopping sequence. If they used that technique, rebinding often would help since the crowded frequencies would change over time. I worked on systems that used that technique and they would rebind at 50 times per second and the cost of them was astronomical, compared to our RC systems, due to the error detection and correction circuitry required.

RC system makers won't provide many details on how their systems work due to competition. Most of the systems on the market today will go into fail-safe when they miss three in a row signals from the transmitter. Fail-safe is normally identified by the aircraft just not responding to transmitter commands, the plane should not do any wild maneuvers, or go out of control, the throttle may go to low if the user set it up that way.

A review of the videos you have may provide a clue to the problem.
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Signed: Steve Rogers (As far as you know)

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Offline Lane C.

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Re: DENTON SWAP MEET AUGUST 4
« Reply #23 on: August 10, 2018, 08:26:13 am »
"Wish we could do some noise sniffing out there.....but if we found something what would we do anyway?  Still I'd like to know.

Gotta be some persons in the DFW area that could help us out

Paul H Lange"


How come the AMA doesn't have an equipment set to check things out at the fields? Since the TX/RX is the HEART of the RC hobby, seems to me the AMA should have a battery of test equipment to loan out to the Districts to use at their fields. With the money we pay out every year in AMA dues, they should put this as their FIRST priority. We need to determine if these events are due to RF problems or just pilot/builder error. I suspect they are pilot/builder error, but that's just my take.

Offline Joystick

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Re: DENTON SWAP MEET AUGUST 4
« Reply #24 on: August 10, 2018, 09:35:02 am »
Back in the good old days, we had a relatively cheap frequency monitor that showed which channel was in use. Problem was that it didn't help if you took off and then someone got on your channel.

I've been flying RC since 1971, on 27 MHz, 72 MHz, and 2.4 GHz, and only had one confirmed crash due to channel interference.
CHECK SIX

Signed: Steve Rogers (As far as you know)

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Offline Paul Lange

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Re: DENTON SWAP MEET AUGUST 4
« Reply #25 on: August 10, 2018, 09:43:49 am »
Well I hope my latest maiden and video was pilot error.....but I don't think so.....the aircraft moved well beyond my sticks...and was not answering any commands for a good two seconds.  I am really hoping it was the flight battery sagging

Regarding the test equipment.....like systems to test the new Auto, Motorcycle computers....a knowledegable field tech needs to set up the system to get good readings and understand what is being seen and what to do with the data captured.  Additionally the hardware shipping is a detail that would probably not suffer the rigors of packing.

BMW motorcycles has a mobile rider trainer booth that is in hard containers....we shipped it from city dealer to city dealer if a local club was inclined to participate in a joint venture with thier local BMW motorcycle dealer shop.....via Fed-X.  Licensed technicians (Trained Saftey Trainers) have to be confirmed to run it. 

I was able to do this for our local BMW club and worked out a deal where the Safety Trainers received service hours on thier records which offset thier volunteered time for the club.

We have plenty of engineering motsy in GSWAM and of course the DFW area.....I will proffer there is equipment all over the place ....we just need to uncover it and get it going.

Paul H Lange
Best Regards - Paul H Lange

Offline Joystick

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Re: DENTON SWAP MEET AUGUST 4
« Reply #26 on: August 10, 2018, 04:10:57 pm »
Paul, if the plane is not responding to the transmitter, that is a good indication of a lockout, and may be due to interference or low battery voltage. Loss of control for two seconds is really bad.

Usually, your in flight battery low voltage would be due to a current surge and not last that long. If your battery was bad without the current surge, you would be able to detect that with your voltage monitor.

One thing that may be an issue is if the binding of the receiver is done on a DSM2 mode receiver. DSM2 is bad, the DSMX mode fixed the problem with it. I don't know if anyone is using DSM2 now, the problem with it has been known for over 8 years now.

It's a little complicated, but Spektrum uses two different frequencies, or channels in the 2.4 GHz band, with the DSM2 mode, the radio may bind the receiver using two frequencies that are very close together instead of far apart. Any interference on one of the frequencies will most likely be on the other one, so the transmitted signal will be too noisy for the receiver to decode. If the two frequencies are far apart, any interference on one of them will most likely not be on the other and the transmitted signal can get through to the receiver.

It is a good thing to check to make sure the binding is done in the DSMX mode.
« Last Edit: August 10, 2018, 05:31:06 pm by Joystick »
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Signed: Steve Rogers (As far as you know)

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Offline Joystick

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Re: DENTON SWAP MEET AUGUST 4
« Reply #27 on: August 10, 2018, 04:58:13 pm »
I just got this info from Spektrum:

Horizon Hobby Product Support <productsupport@horizonhobby.com>  Today at 4:41 PM
To   
rogersjs@flash.net
Message body
Hello Stephen

Thank you for your inquiry. I'm afraid the information you have referenced is not quite accurate.

Back with DSM2 the system optimized each time it was turned on by looking for the best open channels, not during bind, DSMX does not do this.
The DSMX hopping table is based on other factors, never on environmental situations.

If you are able to share with us the source of information from our Spektrum Engineers we would be happy to look further into their statements.


Best Regards
Jeff-

| US Product Support |
CHECK SIX

Signed: Steve Rogers (As far as you know)

Nothing is foolproof to a sufficiently talented fool.

Offline Paul Lange

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Re: DENTON SWAP MEET AUGUST 4
« Reply #28 on: August 11, 2018, 06:56:16 pm »
Steve and I checked over my Denton Swap Meet 72inch PICA WACO for every electrical detail we could poke at.

Intersting findings:
1. The Nmh 6.6v 2300mAh battery was found to be in good shape and did not present any voltage sag under a multitude of loads including, all servos cranking while motor at 50%; Light bulb test; placing additional resistance loads on the servos....the Flight Battery showed no sag to cause concern

2. The servo's had no chatter when back pressure (by hand) was applied during transmitter input

3. There was no wiring solder or connection issues found....by poking evey wire connection while under power and 50% throttle

4. The power connection socket was also poked for loose or wonky connection and was found issue free

5. The 70amp ESC was cleared of issue since the power traine swashed the 18x10inch APC prop at
 38.63amp at WOT while providing 1176.2Watts at WOT

6 We verified and validated the Spektrum Failsafe function...where as all surfaces do go to neutral and motor cuts off during signal loss

Upon further discussion and reveiw of my flight...Steve and I both think I simply stalled this aircraft in the down wind turn of my maiden.  The sudden stall acts the same as if radio control was lost...however as the plane rolled, dipped and then recovered with speed to a nose up position...this in fact would be the same action as a stall.

To me it is gratifiying to check this birds electronics from tip to toe as clear.....and hopefully I can remedie my poor flying habits with this bird.

Thanks to Steve for your time and energy looking over the plane today.....hopefully the rain will clear and our earth will soak all this water up very quickly so our field can be used for normal operations very soon

-Paul H Lange
Best Regards - Paul H Lange

Offline Lane C.

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Re: DENTON SWAP MEET AUGUST 4
« Reply #29 on: August 12, 2018, 05:47:29 am »
Paul, all biplanes have what is called a "built-in headwind" in that they are very "draggy." When you pull back on the throttle it doesn't take long to get very slow. And, whether or not you had begin a turn to the field, that would have added to the loss of energy. Most likely, like you said, you stalled it. I say that since all your components checked out OK. Landing a biplane generally requires that you make your power reductions on final approach, to be on the safe side. The old saying about a Stearman is, "It takes off at 70, cruises at 70, and lands at 70" pretty well explains the biplane experience.