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Hi all,

I just had a great week-end, with our first high altitude flight attempts.

Reached 2670m AGL (3300m MSL) :P

But that was the limit of both the engine without remote needle-valve adjustment possibility and the 100mW video system.

So we switched to the 500mW Fels TX for the next flight. But during take-off, we suffered from very serious R/C dropouts (2 times, more than 1sec each, at 100m distance only!) which resulted in a crash as we were only 10m high when it happened.

We were using a Futaba FF9+R149DP.

Does someone know if there could be interferences between the Fels 500mW and this particular receiver??? :unsure:

I had already used the TX without any problems besides a standard PPM receiver before. So it sounds really strange, it would be the first time ever I see interference between a 2.4GHz video TX and the R/C :blink:

I know this R/C setup was used by cyber-flyer, so I undestand even less...

Any idea?

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Kilrah,

Sorry to hear about the crash. Was the range check ok with the new setup?

I didn't have interferences problem with Felsweb TX and Futaba.

I am using R149DP receiver which is 3 inches away from Felsweb TX on my gas heli. The Felsweb's antenna is 5 inches away from Futaba RX. On my electric helicopter the video transmitting antenna is even closer to RX, still not a problem.

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That's what I remembered..

Yeah, range check was OK. The TX was around 2cm away from the receiver, and the antenna 2 other cm on the outside of the plane, connected via a coax.

The plane can be quite easily repaired, but I think that I'll take the opportunity to switch to a dedicated plane that will eliminate the need to move all the gear every time, and with a decent size not to have to crunch everything in it..

What is actually stupid is that we landed safely after such a trip, and that it happened in the "normal" flight domain :angry:

BTW, didi you simply use a servo to adjust the engine's needle-valve when flying high? And what about temperature? If I remember you were using warm pads, am I wrong?

Maybe if I have more space I can put the TX a bit further away from the RX, it certainly won't be a bad idea.

BTW I had the TL100 inline, but again it was already proved OK. I was relatively amazed as usually it didn't like the proximity of a powerful TX, but this time it was working well.

What a beautiful and clear sight, really love this :rolleyes:

post-16-1114890027.jpg

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2cm is kind of close, I'd definitely investigate more if the range is reliable before attempting any further flights with your setup. I did use simple servo to adjust the needle but it was not necessary until your are above 15000ft. I used warm pads on batteries, Li-Ions really don't like low temps.

Nice picture!

Edited by cyber-flyer

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Thanks, this time the conditions were so good that the 620-line CCD could show its best, before it caught too much oil ;)

Flying with the PLM-S700 was so beautiful!

Just watched the video, really amazing, hope I'll find time to put a piece of it on the web soon.

Okay I'll do some thorough testing before flying again, putting either component as far as I can.

Our engine was really running rich from 2500m on. I had set it at the optimal setting. For the last flight I set it as lean as I could without having it quit, with reduced performance at ground level. But the flight ended a bit too soon to allow seeing the difference :(

Must certainly differ with the brand, the engine is a cheap MVVS one.

So the pads were here only for the batteries, even at 24000ft? Receiver and servos were left by themselves? Whoa!

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I know the prop is a big factor when you start getting to the higher altitudes. The highest I have been was approx 6000 feet AGL flying from video and had spotter with binocs laying on the ground watching the plane. Worked quite well.

I had a crash about a month ago, I took off and had a loose connection in the video system somewhere and it must have made enough noise to knock out my R/C controller . Just as I was coming around for a pass before lining up for landing I lost all control and smacked a gravestone in the adjacent cemetary. You can see the airplane tracking to my control then it just drops the left wing and rolls into the ground.

I had just passed over myself when it happened. Battery checked out fine on a loaded meter afterwards, radio checked out. Who knows.... Motor survived, r/c gear survived and the receiver is relegated to bench use only now.

-----------

I tried to order 500mW felswebs to make a diversity receiver. They are out of stock of the 500mW, I haven't gotten back there to order a smaller transmitter and 2 receivers yet.

Do you have any transmitters that are compatible with blackwidow freq set 1?

Matthew Klarich

www.klarichelectronics.com

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Matt, check your PM.

Kilrah, no need to warm up servos or receiver, they work just fine in the cold. You need to set engine on a lean side before take off, it will be more optimal at altitude.

Edited by cyber-flyer

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We were also spotting the plane with 10x binoculars. But at the end we could only see a dot without being able to tell what was its orientation :blink:

Strange things happen sometimes...

I'm still surprised with the receiver being in the cold, standard electronics are rated at a minimum of 0°C...

Actually I'm not that scared about it, it's a friend who is an electronics engineer who told me I was mad.

I know they tend to be too careful ;)

I watched the video yesterday evening, the engine power dropped significantly at 1900m.

BTW, did you have a thermometer? what was the temp at 24000ft?

--------

If I remember, the felsweb TX have the same freqs than BW set 1.. My Fels RX had bad picture quality (a few distorted lines), so I replaced it with another one that has BW set 1 freqs. I don't know if I tried all channels, but at least 1 is the same... Don't have it at hand now to check.

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Kilrah, I saw several 149DP receivers with a common fail after many uses. Its a broken solder at the pins that fits together the two PCBs it has. Just a possibility. On the other hand I used a 1500 mw 2.4 ghz emitter at 5 cm from my 149 dp and F148 (ppm sinngle conversion) receivers without any glitch.

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It's pretty cold at 24000 ft, don't remember for sure, but I think past 20000 ft, the temperature is stabilized at -50F. Yes, I found that 10x binoculars are only usefull to 10000ft ~ 3000m. After that the handshake will make it very difficult to track the model, one wrong move and you lose your model from binocular's view. Chances are that you will not see it again until you can spot it in the sky with the naked eye.

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Oh, good to know this 149DP issue :blink:

Actually there even are 3 PCBs in it, H-mounted. But this one is not old at all. Well, we'll do some tests with this one... :(

I've lost the model a few times, but managed to find it again by sweeping in "Z" with the binoculars. Actually it was quite hazy sunday so it was difficult to spot the field from the plane... that would have been a third limit. Stupid, saturday was absolutely clear, but we were short of time...

Oh another thing while you're here - we've noticed that air humidity has quite a lot of influence on the range of 2.4GHz systems. Once we flew just after it rained, and at 300m we were already having lots of dropouts with the same system we had this week-end.

Wasn't this a problem when you were doing some cloud flying? It's the next thing I would love to do, so beautiful!

I'm still dreaming every time I watch your 03-06-15 video or the other ones like this :rolleyes:

And there are beautiful low clouds today. But I have to work :angry:

Edited by Kilrah

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Kilrah,

I love flying between clouds. I'd consider it to be the most rewarding outcome of this hobby, worth spending all the time and money.

You are right, the moisture in the air will affect 2.4 Ghz range, sometime very dramaticaly. But I've found that clouds will not reduce the range significantly. The bigger danger is the moisture that can condense on lenses and make camera view illegible. I assume you have GPS return device like PDC-10 on your plane in case you lost visual from your plane.

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I assume you have GPS return device like PDC-10 on your plane in case you lost visual from your plane.

Not yet, that's why I am careful for the moment. This is on the TODO list for this summer. I wanted to do it myself as a part of a whole remote flying system.

I'm getting mad, today would have been perfect for cloud flying, quite a lot of small ones at around 1500m but with enough space between them... but I'm just watching outside the window :angry:

And it'll be raining during my 3 days off :(

The views we can see in your videos just are like magic :rolleyes:

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I'm getting mad, today would have been perfect for cloud flying, quite a lot of small ones at around 1500m but with enough space between them... but I'm just watching outside the window

Well, you've got the bug then. I have exactly the same feeling if I am in the office and its a nice blue skies outside with puffy clouds, calm winds - perfect for flying. What's worse, we don't get many days like that here in Boston.

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Well, that feeling is valid for almost every condition which would be nice to fly in... but I really look forward to trying this particular type of flight!!

Hopefully this week-end IF the weather allows it...

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Is it actually reducing the range of the transmission or increasing the multipaths by bouncing more signals??

Matt

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Is it actually reducing the range of the transmission or increasing the multipaths by bouncing more signals??

Water molecules are resonant at 2.4Ghz. So, they absorb the RF. This is why microwave ovens use this freq.

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Yep. And it can be very amazing. I've been a few times at a field where the air must always be humid, never managed to get a good transmission there. At first I blamed the system (went over there a few consecutive times), but then I tried again at the usual field, and everything was OK again. This place has a strange local climate, that can be seen without this. But you don't make the link so easily...

Also tried other TXs and RX ants there before coming to that conclusion. And when you blast away 200mW and have an awful picture at 100m, you just get mad....

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That gives me an idea, I'll buy a hygrometer, could be interesting to see what influence it has, and know in advance when it will be crappy...

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