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Old Jan 30, 2012, 10:35 PM
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vtdiy's Avatar
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Most people are not aware of what the total stall current for the 4 servos they have, plus receiver plus any other extra gear vs their BEC's rating is. I've seen HXT 9 gram servos rated at 500ma stall current, yet few appropriate sized ESCs are BEC rated at 3A. Good ones tend to be 2A, and lesser ones are rated at 1.5 or even 1A.

Even worse, most linear onboard BECs are given that rating only for their lowest number of cells (2s for instance) and reduce that rating for more cells.

Why? Linear BEC voltage regulators spill excess power as heat. Power is a function of voltage times amperage. Increase the voltage, and you must decrease the amperage proportionately to maintain the same power rating (and heat output).

Excess heat is what fries those regulators.

I don't know if that's the cause of most Orange/Spektrum receiver problems, but I do use those products, pay attention to BEC ratings, and haven't had a lost signal yet. Well, correction, I did once when trying to take off from water in a silver painted plane using not my newer DX6I but a Hobbyzone Champ plastic parkflyer transmitter. I don't think that counts! Flew the same plane fine with the DX6I. Still, I'm looking for that first problem.

My older Hitec FM and AM gear did lose signals occasionally to interference, so I feel this is more reliable.
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Old Jan 31, 2012, 02:41 AM
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yorkshire UK
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Quote:
Originally Posted by vtdiy View Post
Most people are not aware of what the total stall current for the 4 servos they have, plus receiver plus any other extra gear vs their BEC's rating is. I've seen HXT 9 gram servos rated at 500ma stall current, yet few appropriate sized ESCs are BEC rated at 3A. Good ones tend to be 2A, and lesser ones are rated at 1.5 or even 1A.

Even worse, most linear onboard BECs are given that rating only for their lowest number of cells (2s for instance) and reduce that rating for more cells.

Why? Linear BEC voltage regulators spill excess power as heat. Power is a function of voltage times amperage. Increase the voltage, and you must decrease the amperage proportionately to maintain the same power rating (and heat output).

Excess heat is what fries those regulators.

I don't know if that's the cause of most Orange/Spektrum receiver problems, but I do use those products, pay attention to BEC ratings, and haven't had a lost signal yet. Well, correction, I did once when trying to take off from water in a silver painted plane using not my newer DX6I but a Hobbyzone Champ plastic parkflyer transmitter. I don't think that counts! Flew the same plane fine with the DX6I. Still, I'm looking for that first problem.

My older Hitec FM and AM gear did lose signals occasionally to interference, so I feel this is more reliable.
Agreed, most of my problems were bec or even ubec related, most problems happen when a servos goes wrong and draws a bit more current then it should, pushing the bec over the edge and dumping rx voltage, another time a retract did same to a 3 amp UBEC which should easily have coped with 7 servos and 3 retracts, burned out ubec crashed plane.
Where I use 2 cells I never get bec problems even when servo goes wrong I just lose that servo!
However signal loss is something I get now and then on my asw28 but may be something to do with my positioning of battery and rx antenae but there is no other position to put them.
LOCK OUTS are another story, very rare(happened to me once in 4 years or so with ar500 after 40 plus flights trouble free which was sent back and nofault found but replaced with new one) but completey unpredictable and nothing user can do about it.
Imho a separate rx battery would be the only sure way of avoiding brown outs but in small foamies is not usually a viable option, so I just take the risk and fly with bec and ubecs.
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Old Jan 31, 2012, 07:10 AM
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Just a thought, I wonder how well a small 4.8v nimh pack would hold up if it were used in conjunction with a 5v bec, ie just connect it to the 5v like the capacitor that goes on spare channel to smooth out glitches, but with a battery it would actually give some meaningful current for a decent period of time, enough to realize that something is not working and land asap.
I know it would never reach a full charge and would need to be connected only when it is at 5v charge but it would also never get discharged unless there was a problem as it would be charged up by bec!
Any input would be welcome on this as I'm not sure how well batteries last in this kind of situation.
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Old Jan 31, 2012, 10:48 AM
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[QUOTE=Galand;20573320]
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Originally Posted by nigelsheffield View Post
Thanks for that, I have been keeping an eye on the turnigy one for some tiem and it seems most people are very happy with it as long as its updated as you say, but it still looks cheap so I may go over to futaba,..."

You are in for a very pleasant surprise!!!
I have three of those 9 channel Tx's and 15 of the $9.00 Rx's, the first ones bought 2 years ago. Never had a problem. They are built by Flysky and sold by HK, Leaders Hobby, HobbyPartz and others. The upgrade issue mentioned here is old stuff and nobody sells any more "un-upgraded" models.
However doing another available upgrade to the free firmware called Er9x is fantastic and some say makes it the equivalent of a $600 JR or Futaba.
The programming possibilities it offers are amazing.
There is a lot of info on these forums:
a massive one but see post #1 first:
http://www.rcgroups.com/forums/showthread.php?t=1266162
and a more systematic one:
http://9xforums.com/forum/index.php?...d32084099931ac

This is a happy case where cheaper does not equal poor quality!
Hi anyone a member of bmfa as I have not joined and need to contact someone about a tx he has for sale and can only do so if a member but if someone would pass on my email that would be a fantastic help thanks.
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Old Jan 31, 2012, 06:15 PM
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Long Island, NY
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Originally Posted by nigelsheffield View Post
Agreed, most of my problems were bec or even ubec related, most problems happen when a servos goes wrong and draws a bit more current then it should, pushing the bec over the edge and dumping rx voltage, another time a retract did same to a 3 amp UBEC which should easily have coped with 7 servos and 3 retracts, burned out ubec crashed plane.
Where I use 2 cells I never get bec problems even when servo goes wrong I just lose that servo!
However signal loss is something I get now and then on my asw28 but may be something to do with my positioning of battery and rx antenae but there is no other position to put them.
LOCK OUTS are another story, very rare(happened to me once in 4 years or so with ar500 after 40 plus flights trouble free which was sent back and nofault found but replaced with new one) but completey unpredictable and nothing user can do about it.
Imho a separate rx battery would be the only sure way of avoiding brown outs but in small foamies is not usually a viable option, so I just take the risk and fly with bec and ubecs.
Nigel, you may want to look at one of these:
http://www.r2hobbies.com/eng/proddet...od=rcps3946001
They are loike big capacitors and very light.
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Old Feb 01, 2012, 11:06 AM
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some one is selling a turnigy 9x with er9x and usb installer inside along with telemetry frsky 2 way telemetry installed set to be displayed on internal lcd screen fro Ł100 which is about $160 dollars, is this a good deal? been looking at utube lessons and on er9x and seems a bit complicated compared to my dx6i but I suppose I would get the hang of it, the main reason I want telemetry is for a vario and to know how high glider is.
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Old Feb 02, 2012, 01:21 PM
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I was looking as well at the frsky telemetry for the same reasons. However someone from our local flying club reminded me, that a vario without audio output is just money waste... Just my cent.
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Old Feb 02, 2012, 02:23 PM
Feeling the THRALL
Jackson Stone's Avatar
USA, CO, Parker
Joined Dec 2009
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Seagull Sailplane Flight System

Amalka and Nigel,

Seems like the Seagull Sailplane Flight System would be the way to go for a good glider-oriented telemetry system. HK has at http://www.hobbyking.com/hobbyking/s...ht_System.html

Problem is price of $360 for the system. I am surprised that with all the inexpensive electronics someone is not yet making a $100 system for RC gliders. Perhaps they are but I haven't found it yet. Anyone have any ideas on this subject?

Jackson
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Old Feb 03, 2012, 02:19 AM
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yeah, it's crazy when you think of what u can get in a mobile phone, but I we are I suppose a small market in comparison but even so it really is about time someone made a proper cheap telemetry system with a vario and speech for height or any other parameter like speed/battery/amps selectable on a swtich or something and make the bit that goes in the plane very small and light of course as that is key to flying gliders well.
I have decided against buying the er9x system as I dont really need all the funtionality it offers
allthough it is cheap and amazing compared to dx6i it still does not offer the audible vario which is the main thing I want. er9x programmers are saying that they are working on a vario which uses the beeps as audible output but they are also saying that the board is running out of memory and they dont know if they can speeze that function on, but they are working on a new board which will have everything built into one board including a better display driver and better audio driver and a vibrating motor output and usb prgraming;telemetry and an SD card slot so that might be worth having when it gets up and running, time will tell!
Had a nice couple of flights yesterday with both minimoa and asw28 and was thinking how I much I would actually use a vario and to be honest most of the time I can tell when I am in a thermal or not by using my eyes and the thing I really like about the gliders is the peace and quiet so having my vario beeping at me constantly would probably just annoy me and I would just turn it off after a while I recon, it would be nice to have the option though if it did not cost much.
I think a vibrating output for vario might work though, maybe one on each side of tx, one for going up and one for going down and both off if just in a normal glide slope, that would be pretty unobtrusive to both user and fellow pilots close by, and maybe a button to press to give spoken height on request.
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Old Feb 03, 2012, 10:06 AM
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Originally Posted by Jackson Stone View Post
Amalka and Nigel,

Seems like the Seagull Sailplane Flight System would be the way to go for a good glider-oriented telemetry system. HK has at http://www.hobbyking.com/hobbyking/s...ht_System.html

Problem is price of $360 for the system. I am surprised that with all the inexpensive electronics someone is not yet making a $100 system for RC gliders. Perhaps they are but I haven't found it yet. Anyone have any ideas on this subject?

Jackson
Yeah too expensive and I think 900mhz is not allowed in uk anyway if I remember right.
2 flights with moa this aft and wind coming over houses again so not long flight times, but 1st flight was 13 mins and 2nd was 20 mins as I found some thermals
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Old Feb 03, 2012, 02:13 PM
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Jackson Stone's Avatar
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Nigel's Idea

Quote:
Originally Posted by nigelsheffield View Post
Had a nice couple of flights yesterday with both minimoa and asw28 and was thinking how I much I would actually use a vario and to be honest most of the time I can tell when I am in a thermal or not by using my eyes and the thing I really like about the gliders is the peace and quiet so having my vario beeping at me constantly would probably just annoy me and I would just turn it off after a while I recon, it would be nice to have the option though if it did not cost much.
I think a vibrating output for vario might work though, maybe one on each side of tx, one for going up and one for going down and both off if just in a normal glide slope, that would be pretty unobtrusive to both user and fellow pilots close by, and maybe a button to press to give spoken height on request.
Nigel,

Hey you should get in the product development business! That is how Steve Jobs made his fortune and turned Apple into one of the most valuable companies in the world. To follow your lead, I think RC glider pilots would love a vario telemetry product that is (a) intuitive, (b) inexpensive, and (c) unobtrusive. Whether by vibration or sound, we want to know if the plane is going up or down and not spoil the beauty of the experience.

If you don't do this, and it is probably not your expertise, I sure hope someone else does. Frankly this is a world-wide market and there have to be thousands or tens of thousands of customers for the right product. So, the "size of the prize" is worthwhile.

Also happy to hear you have had thermaling flights lately. No such luck here as we are in the grips of a ferocious winter storm. We are covered with new snow and expecting accumulations of up to several feet by tomorrow morning. Tomorrow will be a building day, not a flying day. My next building project is a HK GL-Speedy hotliner. I also have the HK EPO 2.3m Ventus being shipped that I hope to have flying later in February. Should have three sailplanes ready for the upcoming soaring season!

All the best,

Jackson
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Old Feb 03, 2012, 07:20 PM
Firepower
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Originally Posted by nigelsheffield View Post
Thanks for that, I have been keeping an eye on the turnigy one for some tiem and it seems most people are very happy with it as long as its updated as you say, but it still looks cheap so I may go over to futaba, but as you also mention speky dsmx may actually be ok too and has telemtry built in to dx8 but I think there has been problems there too so I will wait a bit longer till somthing with telemetry and glider mixes comes out that is 100% reliable.
I got my dx6i when they first came out and it was sold to me as being the end to all glitches and interferance free and you will never crash unless you do something wrong, well that was not quite right, well actually I never get any glitches that is true and never get shot down by another flyer on same frequency, but have had total lock outs, lost signal which take 8 to 15 seconds to reconnect(better now with newer firmware), and off course brown outs when servos go faulty drawing a bit too much current for bec causing rx volts to drop bellow 3.5v which depending on your point of view is or in not spektrums fault( other rx are quite happy down to 2.5v and less).
Lock outs are rare and have only happened once to me in 4 or 5 years of flying and the rest can be minimized by using decent becs or separate rx batt and placing aerials in proper positions so I am in no rush to replace yet but I will not fly anything too expensive on speky stuff as you just never know when you might get that elusive lock out and trash yr plane.
I think I would have bought a really nice built up powerd glider by now if I was not so worried about rc gear.
I have Futaba so the lockouts are not really a problem unless the BEC is too small. The only problem has been with the MiniMoa which had the standard ESC in it. I had just put on full everything to get it down quickly because something else was in the air, just started to level out and it just spieled into the ground. So that was the BEC or a servo but have not flown it since. It got damaged but I have fixed it and is the only plane I have smashed in 40 years except for a mid-air collision.

In future I will put these on my good planes to avoid any problems.

http://www.wiredrc.com.au/shop/Speed.../prod_695.html

They are a bit expensive and I noticed HK have a few more cheaper ones now but not sure how good they are. I bought four of one type from HK but they will have to go in the rubbish bin.
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Old Feb 04, 2012, 03:18 AM
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Originally Posted by Firepower View Post
I have Futaba so the lockouts are not really a problem unless the BEC is too small. The only problem has been with the MiniMoa which had the standard ESC in it. I had just put on full everything to get it down quickly because something else was in the air, just started to level out and it just spieled into the ground. So that was the BEC or a servo but have not flown it since. It got damaged but I have fixed it and is the only plane I have smashed in 40 years except for a mid-air collision.

In future I will put these on my good planes to avoid any problems.

http://www.wiredrc.com.au/shop/Speed.../prod_695.html

They are a bit expensive and I noticed HK have a few more cheaper ones now but not sure how good they are. I bought four of one type from HK but they will have to go in the rubbish bin.
that looks a better solution then a ubec because if you draw too much currnet from a ubec they seem to blow completely, bit expensive though but I suppose if it saves a plane its worth it. I replaced the esc in minimoa with a hobby wing 30 amp esc as I wanted to reprogram it to nimh anyway and esc does not get warm, in the ask21 I still have original esc and that get very hot and needs 5 min cool down between flights and once a servo connector went dodgy and shut the rx down several times b4 the servo stopped and and I regained control and managed to land( with one aileron stuck down at 45 degree angle) so stock esc is not very good.
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Old Feb 04, 2012, 03:29 AM
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Originally Posted by Jackson Stone View Post
Nigel,

Hey you should get in the product development business! That is how Steve Jobs made his fortune and turned Apple into one of the most valuable companies in the world. To follow your lead, I think RC glider pilots would love a vario telemetry product that is (a) intuitive, (b) inexpensive, and (c) unobtrusive. Whether by vibration or sound, we want to know if the plane is going up or down and not spoil the beauty of the experience.

If you don't do this, and it is probably not your expertise, I sure hope someone else does. Frankly this is a world-wide market and there have to be thousands or tens of thousands of customers for the right product. So, the "size of the prize" is worthwhile.

Also happy to hear you have had thermaling flights lately. No such luck here as we are in the grips of a ferocious winter storm. We are covered with new snow and expecting accumulations of up to several feet by tomorrow morning. Tomorrow will be a building day, not a flying day. My next building project is a HK GL-Speedy hotliner. I also have the HK EPO 2.3m Ventus being shipped that I hope to have flying later in February. Should have three sailplanes ready for the upcoming soaring season!

All the best,

Jackson
I would love a job developing stuff like that, I started out as a electronics enthusiast in my teens and then got a job in tv repairs lol with radio rentals and after 6 years started my own repair business, I have made a few things hear and there over the years but now things are so small my eyesight is not good enough to see the components let alone build them all together lol.
But I think I would make a good ideas man and have something to say about design and impementaion and be part of a team, done some programing in past to but trouble is I can't spell right well and so would need to use spellchecker quite a lot lmfao.
So, any one out there want to give me a job "I'M FREE".( well quite cheap anyway lol).
Nice day out today again just very cold might go for a flight now catch you later hope the weather breaks for you too soon.
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Old Feb 04, 2012, 11:50 AM
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Originally Posted by nigelsheffield View Post
that looks a better solution then a ubec because if you draw too much currnet from a ubec they seem to blow completely, bit expensive though but I suppose if it saves a plane its worth it. I replaced the esc in minimoa with a hobby wing 30 amp esc as I wanted to reprogram it to nimh anyway and esc does not get warm, in the ask21 I still have original esc and that get very hot and needs 5 min cool down between flights and once a servo connector went dodgy and shut the rx down several times b4 the servo stopped and and I regained control and managed to land( with one aileron stuck down at 45 degree angle) so stock esc is not very good.
Actually these Castle CC BEC's are the luxury epitomy of a UBEC defined as a separate BEC i.e. not part of an ESC.
Their blurb correctly criticizes the linear BEC's usually found in ESC's but does not say whether this one is linear or switching.
There is a wealth of BEC info to be found in this thread by Galaxiex:
http://www.rcgroups.com/forums/showp...89&postcount=1
Specifically on the CC 10A BEC:
http://www.rcgroups.com/forums/showp...5&postcount=44
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