redundancy for Very expensive aircrafts??? - RC Groups
Thread Tools
Jul 27, 2010, 07:48 PM
Registered User
Discussion

redundancy for Very expensive aircrafts???


Guys,


I don't fly Jets, but I know some of you will know more about redundancy system for your expensive Jets.

I have Aerial helicopter that cost around $20,000 with video gears. I am looking for ways to make sure the chance of loss signal, or servo battery goes too low, reduce to the minimum.

I know about Power box system, is that the best and reliable system out there for redundancy? Or what other system, or methods do you recommend??

Thanks in advance.


J
Sign up now
to remove ads between posts
Jul 28, 2010, 05:43 AM
Burnin Kero & Diesel Downunder
Marty C...'s Avatar
Use quality accessories and keep it simple is my preferred method. Iam yet to loose a single model in 35 years of aeromodelling due to an electronics system or installation failure. I have never used a power box etc and never use dual receivers or batteries. I always use larger higher spec and torque quality brand servo's and a larger capacity than required battery. Iam a big believer in the K.I.S.S. principal it certainly works for me so I figure why add further complexity, more components that may potentially increase the chance of a failure
Jul 30, 2010, 10:17 PM
I can 3 point
Paul Wilson's Avatar
The beginning is dual batteries and switches. at the very least. The only planes I have with a single battery are foam fun flyers. anyone who thinks having redundant components increases the chance of failure in anyway is completely misguided. I try to get away from single point of failure starting with the components with the lowest MTBF Mean time between failure). that is battery and switches. I have used battery backers and such but I always go back to two batteries and two switches going into one receiver for smaller stuff and dual in 1/4 scale and above.
Jul 31, 2010, 12:18 PM
Burnin Kero & Diesel Downunder
Marty C...'s Avatar
Quote:
Originally Posted by Paul Wilson
The beginning is dual batteries and switches. at the very least. The only planes I have with a single battery are foam fun flyers. anyone who thinks having redundant components increases the chance of failure in anyway is completely misguided. I try to get away from single point of failure starting with the components with the lowest MTBF Mean time between failure). that is battery and switches. I have used battery backers and such but I always go back to two batteries and two switches going into one receiver for smaller stuff and dual in 1/4 scale and above.
Matter of opinion most definetely.... Misguided? hardly, that statement is ridiculous. Common sense says the more components and connections installed the higher possibility of a component failure in theory if not practise at the very least. Speaking from 35 years flying R/C models and having had zero electrical systems failures using single switch and battery installations I must be doing something right. Different strokes for different folks...
Jul 31, 2010, 10:06 PM
I can 3 point
Paul Wilson's Avatar
Marty
Not ridiculous at all. It is simply a fact.
To make it simple. if you have a circuit with a switch in it that has a mtbf of 9 hours(mean time between failure).
That means on average that circuit will fail after 9 hours, though it could be after 0 hours or 18 hours. If you add a second switch with the same mtbf, then that means on average they will both fail after 9 hours. so as you say the possibility of component failure really has increased, that is fact not theory. Most people end there. In actual fact, the chance of both components failing at exactly the same time is on an order of magnitude, giving that redundant circuit a mtbf of thousands of hours. It is not magic or even opinion. It is proven mathematical fact. It is also proven in practice on every almost every aircraft in the world and many other critical applications.
Back to the topic.
Quadman, get some advice from guys who use them, I know smart fly are working on a new one now, I liked the power box system but as I say. Eventually for my really big stuff I customise the channel allocation from two receivers, and just have dual battery packs and dont use switches. I find that a deans plug is easy to charge and just as easy to unplug when I finish flying. My pst panther turbine has no switches and two batteries. cheap and simple redundancy on the most probklem prone part of our models.
good Luck
Paul
Last edited by Paul Wilson; Jul 31, 2010 at 10:17 PM.
Aug 01, 2010, 03:32 AM
Burnin Kero & Diesel Downunder
Marty C...'s Avatar
Like I say each to their own, hey the facts don't cease to exist when they are ignored either... Failure rate for a switch hmmm well I have more than a few JR charge switches in models with well in excess of 9hrs?? never heard any manufacturers warning of iminent failure at that time line? Bottom line I simply don't see why (when using quality equipment) they should be replaced if they are maintained well and checked regularly...

I change my "single" Rx battery pack on average every 18 mths as a precaution. I choose to run single six cell NiCad packs due to ease of maintenance and depending on the model and servo capacity they are between 1800 and 3600 mAh mostly and like I say I have never had a problem and thats the fact also. Iam happy your system works for you but at the end of the day theres always more than one way to skin a cat thats also a fact...
Aug 01, 2010, 07:51 AM
Registered User
you can also add a onboard generator ; most common is a low kv brushless outrunner with a regulating circuit; that will power the system as long your engine/ turbine is running.
Combined with a backup battery you end up with a more user friendly and reliable system.
http://www.sullivanuv.com/home.html
Oct 05, 2010, 09:43 PM
Registered User
GCplane's Avatar
Having worked as a reliability engineer, I can say Paul is right. One more example: if a single system has a 1 in 1000 chance of failure during a flight than a fully redundant system of two sets of the same type parts has only a 1 in a million chance of failure if caused by independent failures. This is probability 101. Marty is right that there is a greater chance of some component failure but the redundancy saves you from crashing.
Oct 10, 2010, 09:45 AM
Registered User
Use the Weatronic radio system. Telemetry allow you to check the quality of the radio signal in real-timer or via logging system. You can setup audio warnings in your transmitter for battery voltage and radio signal quality. Many other things also.
http://www.weatronic.com/
http://www.weatronic-usa.com/
Oct 10, 2010, 07:19 PM
Burnin Kero & Diesel Downunder
Marty C...'s Avatar
Quote:
Originally Posted by GCplane
but the redundancy saves you from crashing.
Yes I do agree with your words in principal... that being said and as long as any secondary redundancy system installed does not become a potential cause for system failure. Iam not anywhere near convinced that either style of install is dramatically superior or 100% safe.

Buy the best (proven) computer radio system possible. Top of the line JR, Futaba or Multiplex would be on my short shopping list, minimum 9 ch. The Weatronics equipment is also proving itself to be mighty impressive and worth doing some research on also.

I fly all my models using a JR 10X system and have done so since 2001, Iam still very happy with this Tx and have no immediate plans to change anytime soon....
Last edited by Marty C...; Oct 10, 2010 at 07:25 PM.
Jun 13, 2014, 10:29 AM
Registered User
sfaust's Avatar
Quote:
Originally Posted by GCplane
Having worked as a reliability engineer, I can say Paul is right. One more example: if a single system has a 1 in 1000 chance of failure during a flight than a fully redundant system of two sets of the same type parts has only a 1 in a million chance of failure if caused by independent failures. This is probability 101. Marty is right that there is a greater chance of some component failure but the redundancy saves you from crashing.
Exactly. With a single switch a failure in flight is a definite crash. With two switches a failure in flight is a non event, and it would just be replaced after landing. (been there, done that Two switches increase the probability of a failure of a single switch, but at the same time significantly lowered the probability of a switch failure causing a crash, which greatly increases the reliability of the aircraft.

One persons luck also doesn't mean others will fare the same fate. When one of my switches failed, I replaced it upon landing. It was the only switch that has ever failed on me in my years of flying. Redundant switches saved that airplane (40% Carden Extra). 12 years later I still have that airplane because I installed dual batteries and switches, a cheap insurance policy that worked. If I hadn't bought that switch, some else would have! And if it would have been their only switch, they wouldn't have been very happy with their purchase.

I've been driving for 40years without ever needing the safety provided by seat belts. But it would be irresponsible of me to tell others that they dont need seat belts based on my sole experience. Statistically I've been lucky, many others have not.
Jun 14, 2014, 08:11 PM
Too many numbers
Aerial helicopter with video gear? Sounds like a multicopter. Yes? Your main concern there is your flight controller. Get one with return to home and you won't have to worry about losing signal from the radio- as long as the RTH system is smart. Mine will stop, hover for a few seconds, fly up about 200 feet. hover and see if it can regain contact, and if not, fly home and land where it took off. Go to the multi-rotor forums for more information. There really is no redundancy with electric helicopters or multi-rotors because everything gets its power from the main battery. With my big hexacopter, I use two batteries in parallel, so I suppose you could say I have redundancy, but the flight controller is more important- if the FC sees my voltage is going too low, it will either fly home and land, or if there is no time, simply land and shut itself off.
Jan 11, 2017, 02:07 PM
Registered User
Would you rather jump of a plane equiped with one parrachute or two (one as a backup)?
Thats what i tought.
Any misshap can happen to the highest quality equipement, for that, redundancy is the only way to go. The kiss method applies on gizmos, telemetry ect..which the plane dont depend on to fly.
Your right! Each its own way and thats why there exist companies like air canada and air france for reliable transportation as supose to air zimbaboe.
If you use the kiss method for important companants like receivers, batteries, servos! Well you are considered like air zimbaboe for rc planes hobbiests.
Jan 12, 2017, 06:17 AM
310mph Kolibri T25 Swist
henke's Avatar
Quote:
Originally Posted by Marty C...
Use quality accessories and keep it simple is my preferred method.
I agree. Keep it simple and UNDERSTAND what the heck you are doing when soldering, programming your radio, routing antennas and charging batteries. Those who buy turn key planes are the really brave guys

While keeping it simple there are still ways to get redundancy without adding allot of weight or complexity. I would never ever add a powerbox with dual batteries, but I would add an optipower for example to get that extra safety.



OPTIPOWER ULTRA GUARD 430 - Working demo (1 min 31 sec)
Jan 12, 2017, 07:05 AM
KingtechUSA
gunradd's Avatar
Guys this thread is from 2010....... Pretty sure he has it figured out by now.


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion very expensive ooops rchawks Crash Discussion 5 Apr 18, 2008 10:24 AM
Discussion Very expensive AP setup with very impressive crash... glydr Aerial Photography 3 Sep 04, 2006 10:36 PM