Alpha 40 Crash
12-03-2009, 10:16 PM
#26
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RE: Alpha 40 Crash
I too have had issues with spektrum, I bought the DX7, and near lost my 72"Katana and did total my 174" glider. I was running 4s2p A123 packs in both, regulated to 6V, the glider had just had a full rebuild, with all new h'ware and servo's and I bought the DX7 specifically for it and my other gliders. I bought a 2nd rx and decided to see how my katana behaved with the new DX. My Katana had near 200 flights with my trusty jr10x on 36meg (aust freq) with no issues at all, and my glider the same. In both cases about a min or so into the flight the planes went into a hard right roll with full down elevator, the Katana also went to wot. The glider drove into the ground nose first and was a total write off, was luckier with the Katana, it went into a cane field more or less level, only damage was to the covering and a busted prop and losened landing gear. After we retrieved the Katana, we checked everything thouroughly, and found the tx/rx binding was lost, so we (there were 5 of us, all long time rc'ers) reset it and played with some to have the same happen on the ground, and repeated it several times with same results. I tried again at home that afternoon and could get it to do it again. After contacting the Spektrum agents and explaining what had happened they told me I didnt have a clue, and to stick to 2 channel park flyers [:@] I told the jerk that I have been using 2 jr10x's and still have my jr388, and several smaller tx's which I have never had any hassles with at all. he then told me he has had no other calls complaining about the spektrum gear, which I knew to be crud, and he hung up on me. I quickly ebayed my DX7 and have gone back to 36meg. since then I have put about another 150 flights on my katana and no issues whatsoever. The only thing that was changed in the Katana was the rx, and that was near the end of it. Whatever the issues were I may never fully know, nor do I care, I will NOT contemplate Spektrum again, and I shudder at the thought of replacing my radios and rx's with either jr or futaba 2.4 systems, I have 2 10ch, 6 9ch, 9 7ch and numerous 5 and 6 ch rx's, most in planes. Also while I have had very few issues flying on 36m i dont see the point in spending enough to buy car to update(?) to a system that failed me from the start. [&:] As has been said here, if it aint broke dont fix it
12-04-2009, 11:36 AM
#27
RE: Alpha 40 Crash
I have not had time to work on the Alpha but did recently buy a Jr 7202 and have been flying my Falcon 56 MkII with it and had no trouble. I will most likely use this radio when I rebuild the Alpha this winter. I haven't decided yet what to do with my DX5e and AR500. I may sell them but I hate to. I will post some pic here when I get the time to work on the Alpha.
12-05-2009, 02:43 AM
#29
RE: Alpha 40 Crash
ORIGINAL: tacx
So, qldviking, You ''ebayed your dx7''. Does that mean some poor sap is now going to loose HIS plane??????
So, qldviking, You ''ebayed your dx7''. Does that mean some poor sap is now going to loose HIS plane??????
12-05-2009, 07:56 AM
#30
RE: Alpha 40 Crash
At our field I have only observed two major issues with 2.4 radios and we have quite a few 2.4 systems (Futaba and Spektrum). I would say at least five or more any given weekend and some times there are three to five 2.4s flying at the same time.
In the past year the two main issues have been connectors (not secure, vibrating, etc.) and antenna position! That is it! One fellow is even running receiver batteries in a gasser that is almost five years old with a 2.4 system. We really have not found batteries to be a problem as long as they are charged up properly. Granted you can improve your battery system by upgrading, but we have guys flying 2.4 with standard battery packs for years now with no issues.
I fly about four different planes every week with mine and another guy I know has two choppers and two planes he puts in the air weekly. Not one glitch can be attributed to any fault of the radios at this time. I had noticed that when I had glitches it was always in the same area of the field and I could not figure out what was going on (almost lost a plane a couple times there). I started monitoring this more closely and found that all I had to do was move my antenna slightly and all was good! Not one more glitch in that area.
One note about attenna position. What we have found is the antenna should not point at the plane in the air and should have a slight angle that when flying would never point to the plane. As with most antenna systems there is what is called a "dry spot" with the the field of reception. Most RC pilots fly through this "dry spot" and never realize it.
True Diversity antenna systems help with the "dry spots" issue because they have two antennas and switch signals back and forth for redundancy (not sure if rc radios are currently using this technology). A lot of 2.4 systems have redundant receivers which is a great feature that will help with the reception issues. Systems are much improved now and there should be rarely an issue, however, sometimes there are defects and bad components.
In the past year the two main issues have been connectors (not secure, vibrating, etc.) and antenna position! That is it! One fellow is even running receiver batteries in a gasser that is almost five years old with a 2.4 system. We really have not found batteries to be a problem as long as they are charged up properly. Granted you can improve your battery system by upgrading, but we have guys flying 2.4 with standard battery packs for years now with no issues.
I fly about four different planes every week with mine and another guy I know has two choppers and two planes he puts in the air weekly. Not one glitch can be attributed to any fault of the radios at this time. I had noticed that when I had glitches it was always in the same area of the field and I could not figure out what was going on (almost lost a plane a couple times there). I started monitoring this more closely and found that all I had to do was move my antenna slightly and all was good! Not one more glitch in that area.
One note about attenna position. What we have found is the antenna should not point at the plane in the air and should have a slight angle that when flying would never point to the plane. As with most antenna systems there is what is called a "dry spot" with the the field of reception. Most RC pilots fly through this "dry spot" and never realize it.
True Diversity antenna systems help with the "dry spots" issue because they have two antennas and switch signals back and forth for redundancy (not sure if rc radios are currently using this technology). A lot of 2.4 systems have redundant receivers which is a great feature that will help with the reception issues. Systems are much improved now and there should be rarely an issue, however, sometimes there are defects and bad components.
12-05-2009, 08:01 AM
#31
RE: Alpha 40 Crash
I never had liked the cheep feal of the DX5/DX6/DX7 transmitters and to have such a low voltage pack in the Tx does not make sense to me. I paid way to much and just got the JR X9303 and have never had a problem. The JR model is also easier to set up with a far more intuitive interface. A freind was setting up a GP Edge 540 the other week on his DX7 that required use of the Ele/Aux2 channels for the elevator and he could not get it working right so he brought it to me. Well once we flipped the Aux to switch (a 2 position switch on the DX7 but a 3 pos switch on the JR X9303) to it's neutral position we were able to get the elevator halves to move the same distance. Then I told him we needed to "inhibit" the Aux2 switch to avoid accedental use of it during flight (this would cause one elevator half to deflect aprox 30 degrees opposed to the other half) So we looked though his manual and could not find how to do this. rRediculous cheep POS.
12-12-2009, 11:31 PM
#32
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RE: Alpha 40 Crash
When I listed the tx/rx I stated i had issues with it, and the guy who bought called me and discussed what had happened. He seemed to think it was operator error. I also sent the warranty papers with it too. Since my last post I called him, and he too has had the same issue too, and sent both tx and rx to be checked out. He was told that the rx was faulty and would not hold binding and got a new rx, and he hasnt had a problem since. He also told me of other issues he has seen with DX radio gear.
As for not setting the gear up right, how the *&%* do you set up for faulty rx's? From the feedback I am getting from people all over aussie it looks to me that the DX range had a bad batch of rx's hit our stores, but thats by the by, I will NOT consider buying any Spektrum 2.4 crud again, and while 36mhz works well, and is still legal here i will stick with it. I have over 20 yrs experience in rc, and had my share of crashes, but only once through radio issues before, and that was a faulty tx battery pack. The day I tried to fly with the DX7 there were 5 of us with over 100 yrs experience between us in rc, and we went by the book checking everything before flying. But as I asked, how do you set up for a faulty rx?
As for not setting the gear up right, how the *&%* do you set up for faulty rx's? From the feedback I am getting from people all over aussie it looks to me that the DX range had a bad batch of rx's hit our stores, but thats by the by, I will NOT consider buying any Spektrum 2.4 crud again, and while 36mhz works well, and is still legal here i will stick with it. I have over 20 yrs experience in rc, and had my share of crashes, but only once through radio issues before, and that was a faulty tx battery pack. The day I tried to fly with the DX7 there were 5 of us with over 100 yrs experience between us in rc, and we went by the book checking everything before flying. But as I asked, how do you set up for a faulty rx?
06-14-2010, 12:58 PM
#33
RE: Alpha 40 Crash
We just lost an Alpha 40 too 
I have been buddy boxing at our club every Tuesday afternoon for a few years now. I have boxed many new pilots and old ones brushing off the dust. I personally fly mostly gas planes 26, 30, 50, and 100cc. I have never had any problem with my JR/Spektrum equipment until now. I also do not use anything smaller than an AR7000 in my gas stuff and my two big ones (50 & 100) are running (921 with two satellites).
Our club purchased two new RTF Alpha 40 trainers this past spring for training. We retired our old trainers after having three years on them.
Set Up:
Standard Alpha 40 except the battery was changed to a 5 cell 2000mah
Using 6i Tx
Range check before first flight
Student takes off perfectly left to right, student makes left turn into traffic pattern, about a 150 feet from where he took off he tells me "I don't have the plane", I quickly took the plane, had plenty of altitude so no worries at all until I realized I had no control either, tried to recover until the ground won. We had absolutely no control, the aircraft never went into fail safe either which I had personally set up a month or so ago on both new planes.
Upon reaching the crash site:
It was a mess to say the least. The AR500 Rx was still connected to the switch and all wires were secure. The Rx light was slow blinking (Tx left on and still near the pilot station maybe 300 feet away). While walking the remains back to the pit area the Rx light went back solid (about 1/2 way back, about 150 feet closer).
The battery test:
After the Rx light went solid we had control over all working servos (some were damaged). We check all connections one last time and everything looked good. We disconnected the Rx battery and hooked it up to a load tester, the battery held from 6.5 to 6.4 volts for an entire 3 minutes under a 1 amp load. We checked the pack, wiggled the cells, etc. pack seems perfect even after the crash.
Tx:
The master was a 6i and had 5.9 volts at the bench after the crash, the low voltage warning is supposed to come on at 4.3 volts. We should have been fine here. The slave Tx was a 9503 at the time, it had 10.5 volts showing.
After some discussion we found another member "thought he lost control" over the other trainer while using his 9503 a few weeks earlier. He did regain control after about 3 seconds. Checked the Rx light on that AR500 and it was solid upon landing.
Conclusion:
I really have no idea but I think we will change our trainers to a little higher end Rx with a satellite. I for one do not trust the AR500 at this point. If it isn't full range as some have said then why supply it with a 40 size glow trainer?
I have contacted Horizon; they have asked me to return the remains for examination. Will get this shipped soon.
Cheers,
Steve
I have been buddy boxing at our club every Tuesday afternoon for a few years now. I have boxed many new pilots and old ones brushing off the dust. I personally fly mostly gas planes 26, 30, 50, and 100cc. I have never had any problem with my JR/Spektrum equipment until now. I also do not use anything smaller than an AR7000 in my gas stuff and my two big ones (50 & 100) are running (921 with two satellites).
Our club purchased two new RTF Alpha 40 trainers this past spring for training. We retired our old trainers after having three years on them.
Set Up:
Standard Alpha 40 except the battery was changed to a 5 cell 2000mah
Using 6i Tx
Range check before first flight
Student takes off perfectly left to right, student makes left turn into traffic pattern, about a 150 feet from where he took off he tells me "I don't have the plane", I quickly took the plane, had plenty of altitude so no worries at all until I realized I had no control either, tried to recover until the ground won. We had absolutely no control, the aircraft never went into fail safe either which I had personally set up a month or so ago on both new planes.
Upon reaching the crash site:
It was a mess to say the least. The AR500 Rx was still connected to the switch and all wires were secure. The Rx light was slow blinking (Tx left on and still near the pilot station maybe 300 feet away). While walking the remains back to the pit area the Rx light went back solid (about 1/2 way back, about 150 feet closer).
The battery test:
After the Rx light went solid we had control over all working servos (some were damaged). We check all connections one last time and everything looked good. We disconnected the Rx battery and hooked it up to a load tester, the battery held from 6.5 to 6.4 volts for an entire 3 minutes under a 1 amp load. We checked the pack, wiggled the cells, etc. pack seems perfect even after the crash.
Tx:
The master was a 6i and had 5.9 volts at the bench after the crash, the low voltage warning is supposed to come on at 4.3 volts. We should have been fine here. The slave Tx was a 9503 at the time, it had 10.5 volts showing.
After some discussion we found another member "thought he lost control" over the other trainer while using his 9503 a few weeks earlier. He did regain control after about 3 seconds. Checked the Rx light on that AR500 and it was solid upon landing.
Conclusion:
I really have no idea but I think we will change our trainers to a little higher end Rx with a satellite. I for one do not trust the AR500 at this point. If it isn't full range as some have said then why supply it with a 40 size glow trainer?
I have contacted Horizon; they have asked me to return the remains for examination. Will get this shipped soon.
Cheers,
Steve
06-15-2010, 02:30 AM
#34
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RE: Alpha 40 Crash
ORIGINAL: Eganwp
Here's a tip from my experience with easily over 700 flights on my DX6i.
You must must must must use a 5 cell RX battery on the spektrum rx's!!! Even if the battery is fully charged on a 4.8, especially if you're running standard size or larger servos, if you operate all surfaces together the amp draw will be too much and cause the RX to brown-out. I've seen it over and over again. You may not notice it on the ground, but when a plane is flying there's huge forces on the surfaces if flying fast, and that amp draw can go through the roof quite easily. The problem is magnified even more if you have a surface that is sticking or end-points not adjusted correctly. Take a voltmeter (or measure current draw) at home while using all surfaces and weighting them all in some way (like lightly taping them and using sticks very gently to not strip gears). Don't be suprised when the voltage drops a ton.
A 5 cell RX battery will solve nearly all the issues, as it's much harder to hit the LVC for Spektrum's RX's with these, even if they're only partially charged. It's also worth noting that if you're running NIMH batteries to switch back to NICAD's as their loaded voltage doesn't sag close to as much as NIMH. I run A123 and LIPO's now almost exclusively and absolutely love the extra servo performance. There's a reason why you'll notice you hardly ever see an electric pilot have Spektrum issues (aka most beginners now are going with electric park fliers), and it's because lipo's can handle the load like nothing as most of them are using a UBEC or BEC on the ESC to power the RX. The load doesn't even break a sweat on LIPO's or A123's!
The other 2 things I can suggest are that you ALWAYS point your antenna straight up. I've seen it for myself at the club where guys have the antenna pointed to the side and the plane cuts out when directly in line with the antenna. When at a club you should never have your plane directly overhead.
One last thing is I would recommend you run an AR6200 or 7100 RX with a satellite receiver. The AR500's are only designed for the small park fliers I believe, and the range and spectrum will be a lot smaller. This problem is worth if mounted near servos, carbon fiber, thick fuse wood, etc. A second antenna will make a huge difference.
Lastly is something I just learned a few days ago. I always thought you were supposed to ''do it backwards'' with these radios and turn on the RX then the TX. BUT after some testing and speaking with Spektrum on this, it's actually wrong!!! I found I couldn't get a link (flashing RX) when turning on TX first, but the reason why is I either wasn't waiting long enough, or else I had the TX too close to the plane (must be more than 4 feet away). What happens is, if you turn on the RX first the RX will automatically use the last 2 used channels from your last flight. Problem is, these channels may very well have interference, especially if you're at a new location! So when you turn on the TX, it see's the RX is transmitting those 2 channels and binds, AND DOES NOT SCAN THE FREQUENCY CHANNEL FOR CLARITY. I have confirmed this with Spektrum as well as Horizon.
What happens if you turn the TX on first (like the old 72mhz) then the RX is it will scan the 2.4 band and find 2 clear channels like it's supposed to, giving you complete path redundancy. I wish I would have known this a long time ago! lol
Anyway, hope this helps. Sorry it's long. Maybe I'll type up a more in-depth guide for a sticky.
Cheers!
Eganwp
Hope this helps.
Here's a tip from my experience with easily over 700 flights on my DX6i.
You must must must must use a 5 cell RX battery on the spektrum rx's!!! Even if the battery is fully charged on a 4.8, especially if you're running standard size or larger servos, if you operate all surfaces together the amp draw will be too much and cause the RX to brown-out. I've seen it over and over again. You may not notice it on the ground, but when a plane is flying there's huge forces on the surfaces if flying fast, and that amp draw can go through the roof quite easily. The problem is magnified even more if you have a surface that is sticking or end-points not adjusted correctly. Take a voltmeter (or measure current draw) at home while using all surfaces and weighting them all in some way (like lightly taping them and using sticks very gently to not strip gears). Don't be suprised when the voltage drops a ton.
A 5 cell RX battery will solve nearly all the issues, as it's much harder to hit the LVC for Spektrum's RX's with these, even if they're only partially charged. It's also worth noting that if you're running NIMH batteries to switch back to NICAD's as their loaded voltage doesn't sag close to as much as NIMH. I run A123 and LIPO's now almost exclusively and absolutely love the extra servo performance. There's a reason why you'll notice you hardly ever see an electric pilot have Spektrum issues (aka most beginners now are going with electric park fliers), and it's because lipo's can handle the load like nothing as most of them are using a UBEC or BEC on the ESC to power the RX. The load doesn't even break a sweat on LIPO's or A123's!
The other 2 things I can suggest are that you ALWAYS point your antenna straight up. I've seen it for myself at the club where guys have the antenna pointed to the side and the plane cuts out when directly in line with the antenna. When at a club you should never have your plane directly overhead.
One last thing is I would recommend you run an AR6200 or 7100 RX with a satellite receiver. The AR500's are only designed for the small park fliers I believe, and the range and spectrum will be a lot smaller. This problem is worth if mounted near servos, carbon fiber, thick fuse wood, etc. A second antenna will make a huge difference.
Lastly is something I just learned a few days ago. I always thought you were supposed to ''do it backwards'' with these radios and turn on the RX then the TX. BUT after some testing and speaking with Spektrum on this, it's actually wrong!!! I found I couldn't get a link (flashing RX) when turning on TX first, but the reason why is I either wasn't waiting long enough, or else I had the TX too close to the plane (must be more than 4 feet away). What happens is, if you turn on the RX first the RX will automatically use the last 2 used channels from your last flight. Problem is, these channels may very well have interference, especially if you're at a new location! So when you turn on the TX, it see's the RX is transmitting those 2 channels and binds, AND DOES NOT SCAN THE FREQUENCY CHANNEL FOR CLARITY. I have confirmed this with Spektrum as well as Horizon.
What happens if you turn the TX on first (like the old 72mhz) then the RX is it will scan the 2.4 band and find 2 clear channels like it's supposed to, giving you complete path redundancy. I wish I would have known this a long time ago! lol
Anyway, hope this helps. Sorry it's long. Maybe I'll type up a more in-depth guide for a sticky.
Cheers!
Eganwp
Hope this helps.
