Powerbox 'Royal' Spectrum in over 20kg models?

[tony hooper]

Phil and all

I was interested in the comment from one of the contributors to this topic that on failure "a crash is not acceptable". The criteria agreed with the CAA for Over 20kg control systems which is promulgated in the Inspectors Guide is as follows
"Upon the failure of any single point in the airborne control system, the model should still have sufficient control to enable a controlled landing to take place".
In this context the safety concern is that the model does not go completely "out of control" but the pilot has the "limited" availability to turn away from any specific area which may cause damage to property or person. The CAA have always accepted that crashes may take place within the dedicated flying zone at a public event and would only become very concerned if an incident took place in the public area or outside the flying zone. The purpose of the redundancy system is to ensure that this takes place even if the model is badly damamged or even written off in the process.
Getting back to the Powerbox issue the above criteria is the one that should be addressed. The Powerbox RRS has the facility to operate 2 Rx's and 2 power supplies. In the case of the UAV I mentioned the Powerbox was connnected to 2 rx's and was capable of switching if there is a Rx failure. In the Weatronics system the Rx's are integral to the whole unit - in the Powerbox RRS set up the 2 rx's are connected to the box and are not integral but the principle appears to be the same. Without wishing to become involved in a "techy" dabate I am prepared to be challenged on this.
We must all bear in mind that the LMA is on a learning curve with 2.4Ghz installations and there are now developments which change our traditional methods , tried and tested , with 35MHz . To date some 20 2.4Ghz installations have been approved in Over 20kg models and test flying has proved to be incident free
So long as we keep to the criteria established with the CAA which I have referred to above when approving Over 20kg radio installations then there should not be any problems. Inspectors simply have to ask themselves this question about a specific installation "If a Rx or a battery fails is there sufficient limited control to enable a controlled landing to take place away from danger"

[Simon Willey]

Hi Tony
I am still lost as to the use of the Royal Spektrum unite which is the unite Phil is referring to. This is a totally different unite to the RRS unite from what I can see.
The RRS unite allows to independent RXs along with there satellite antennas to be plugged into it.You can use any RXs you want to .There is no decoupling between battery supplies on the RXs feeding the unite unless you provide it yourself The Unite itself is the single point of failure in this case.
In the Royal Spektrum unite there is one main internal RX along with the ability to add satellite antennas but they share the main RX board so in reality it has only one RX but lots of antennas.It dose have the ability to have decoupled power supply's with built in soft switches.
Thats how I read it but as usual I am probably wrong.

Regards Simon

[tony hooper]

Simon

Without wishing to prolong this discussion I have, all along, referred to the Powerbox Royale RRS system. Powerbox produce a whole range of different specifications as promulgated on their website. I cannot re-iterate enough that every Over 20kg model builder is appointed an Inspector who offers guidance on the whole project and will give a formal Final Inspection approval.
Because there are so many different ways of installation to achieve the CAA criteria that I quoted in my previous post it is essential that all builders of Over 20kg models discuss these issues with the appointed Inspector. It cannot be accomplished "out of situ".

[Simon Willey]

What is the official word on the suitability (or otherwise) of the Powerbox 'Royal' Spectrum 2.4 system in over 20kg models?

http://www.powerbox-systems.com/e/powerbox_systeme/powerbox_royal_spektrum/start.php

Phil

Ok so we are talking about a different unite than the one Phil asked about.
You did not make that clear in your answer to his question( The Powerbox "Royale" works in a similar way to the Weatronics system and thereby complies with the "redundancy" requirements.
It has 2 Rx's (which can be augmented by satellite aerials) and also has 2 independant battery supplies to the unit.)
This is where the confusion has come from. You are talking about a unite that you fit external RXs to and has not got any built in.

This is the one Phil asked about.


This is the one you are talking about


Thanks that clears that up Tony

Regards Simon

[Phil Clark]

My initial post was regarding the Powerbox 'Royal' Spectrum 2.4 unit.............I made no mention of the Powerbox Royal 'RRS'.

It appears we have been talking about 2 completely different units here :-(

[Tim Currie]

Tony,
One very interesting point that has come out of this discussion has been that the Powerbox RRS introduces a single point of failure into the receiver installation so would not meet the criteria agreed with the CAA – “Upon the failure of any single point in the airborne control system, the model should still have sufficient control to enable a controlled landing to take place".

I’m sure if we were to be given the circuit diagram for some of the other Powerbox units or Weatronic units we might see shared components which could produce a single point of failure.

But if the criteria is actually only “If a Rx or a battery fails is there sufficient limited control to enable a controlled landing to take place away from danger", then the Powerbox RRS plus two receivers/ two batteries, and the Spektrum Powerbox and the Spektrum AR12100 should all be acceptable?

I understand that we discuss the installation with our inspectors but it would be useful if we knew what was the actual criteria we were trying to meet and which 2.4g units were acceptable for these over 20 Kgs models?

Tim

[Martin Waller]

By Martin Waller 1237

I have read with interest the comments in this section as I use Powerboxes on my smaller models with the Weatronic micro 10channel receivers. I though I would read the manufacturers instructions for the systems concerned on the Powerbox website and the answers are there quite clearly described .

The Powerbox Royal Spectrum has one reciever and two power suppliers and uses four satelite receivers to collect the signal for the SINGLE MAIN RECIVER and DECODER. This is clear in the instruction sheet. It also states that it is suitable for models between 2.5 th 3.2 meters span. This I would have thought would rule out over 20kgm. It does not have a very high current rating either.

The Power Box Royal RRS (Receiver Redundancy System) is a completey different product and is suitable for over 20kgs as it has two independant power supplies and uses two separate main receivers which plug into the unit to drive 7CHANNELS only. The remaining sevos for channels 8 to 12 are plugged into either one of the two receivers direct so no redundancy on these channels.

The Power Box Champion RRS is similar to the Royal RRS and caters for two separate receivers in the same way up to 7channels but has fewer functions.

The Power Box RRS offers a lighter lower power option to the above two but is limited to only five channels for receiver redundancy and a much lower current rating so suitable for small models requiring receiver redundancy and two power supplies.

I would comment as below as a private individual:
The Weatronic 12-22R and higher models offers all the above and much more. Full receiver redundacy on all 12 channels soon to be 16 with MC32, eight separate voltage regulators.
automatic matchboxes with up to eight servos on each control suface, 32amps continous rating with peaks of 50amps covered for a few minutes, ground range of over 3kilo meters air raange 2.5 to 3 times that. Full telemetry all inclusive in price back to TX and computer plugged into Tx to read in real time such things as RX heat sink temp, good frames signal strength to Rx and signal strength back to Tx on both channels, theseare all alarmed back to Tx leads as well. See Weatronic site and dowload instructions. I have 11 of these systems in my models. System is so powerful it only needs one aerial for each receiver and with the 12-22R these can be on long extension leads and external to the model well clear of obstructions.

Eur Ing M J Waller BSc(Hons) C.Eng, MIET

[Tim Currie]

Martin – please could you indicate where on the Powerbox Manufacturers instruction sheet it “Clearly describes” that “The Powerbox Royal Spektrum has one receiver?

Or where it clearly describes – “and uses four satellite receivers to collect the signal for the SINGLE MAIN RECIVER and DECODER”?

What I did find on the Powerbox system instructions was this - "The Powerbox Royal Spektrum is the latest innovation from the Powerbox System stable. The unique feature of this unit is that for the first time it includes an integrated receiver module. This saves space, weight and connecting leads which always represent a potential source of errors. The technology employed is the Spektrum 2.4GHz DSM2. The system offers the option of connecting a maximum of four satellite receivers, providing four-way redundancy of the radio link, which in turn means maximum possible transmission security. As with all Powerbox products, all the components, ICs, micro-controllers and electronic circuits required for a reliable power supply system are duplicated!"
Martin - This is a whole lot different from your description on the Powerbox Royal Spektrum.

You also state that - “It also states that it is suitable for models between 2.5 to 3.2 meters span. This I would have thought would rule out over 20kgm.”My F-14 has a wingspan of 2.6m fully swept forward and less than 1.6m swept back and is over 20 Kgs. So what has the wingspan got to do with “rule out over 20 Kgs”?

You stated – “It does not have a very high current rating either.”Where does it state this?

Tim

[BRIAN RAWCLIFFE]

Tim,klick onto powerbox spectrum, scroll down to operating instructions then klick on to download and you will see it.
Brian..

[Tim Currie]

Sometimes better asking the makers –
Hello Tim,
We have had many of pilots in Germany, France and U.K. they take the PB Royal Spektrum for models over 25 kg, we have this limit in Germany and France. It is so that the Spectrum have 4 receivers, when 3 receivers fault then you can fly with the last, only with one of the remote receivers. Inside the Royal it is 2 times the same as by the RRS system, we have in the PB Champion and the PB Royal or the RRS module. This system looks what receiver has the best range or is function, in the Display of the PB Roayal Spektrum you can see what is happened with all 4 receivers. Only the disposition IC for the 12 channels is only one time inside, so we write that the 12 channel is inside, but this is not the receiver. Also is the power for this receivers inside double, the regulators, the switches and so on. In France we have made an accreditation by the aviation administration for the models over 25 kg with the PB Royal Spektrum, our dealer in France Marc Hauss has the certificate that this is allowed in France to fly with this PB Royal Spektrum in 25 kg models and here in Germany we get this certification after the adjudication I think in March or April we have it.
kind regards / mit freundlichen Grüßen
Emmerich Deutsch
PowerBox-Systems GmbH
zertifiziert nach DIN EN ISO 9001:2000

[Tim Currie]

Brian,
Yes these are the same operating instructions I am looking at.
http://www.powerbox-systems.com/e/power ... /start.php

Please tell me where it clearly states – “The Powerbox Royal Spectrum has one reciever and two power suppliers and uses four satelite receivers to collect the signal for the SINGLE MAIN RECIVER and DECODER?

I look forward to your response,

Tim

[BRIAN RAWCLIFFE]

Tim. firstly i am not a Spectrum/ JR user,juat a member who has been following this interesting post.
I read the specifications for the Power Box Royal Spectrum and if you select FEATURES it states as follows.
Integral Spectrum 2.4 DSM2 12 channel receiver [NOT RECEIVERS] and uses 4 satellites, with no metion of a second main receiver and decoder.
Secondly,my post was to simply point out to you that the info you required was in the instruction download.
End of posting from me. best of luck..Brian.

[Tim Currie]

Thanks Brian,

Features – “Integral Spektrum 2.4DSM2 twelve-Channel Receiver” Integral means – “Essential or necessary for completeness”.
In other words this is a Powerbox Royal with a Spektrum12 Ch receiver system included. And we already know that the Spektrum 12 channel system have 4 external receivers. Also any common component inside the Powerbox Royal have duplicate circuits and/ or two power supplies.

So if we were following the criteria of - “If a Rx or a battery fails is there sufficient limited control to enable a controlled landing to take place away from danger", then this Spektrum system has 4 receivers so if one receiver fails, then it still works fine?

But if the criteria is to ensure there was not a “single point of failure”, then this is a whole new area. The only way I can see this being truly met is to have two separate receiver unit with their own batteries and splitting up the controls. But this introduces the problem – will the model still fly on 1 receiver/ limited control?

Is there a committee in the LMA that approves equipment like this one? If not should there be?

Also in the UK it is a 20Kgs limit but Germany/ France it is 25Kgs. Is the LMA looking into standardising with Europe on this 25 Kgs limit?

Tim

[Mark Partington 2989]

Also in the UK it is a 20Kgs limit but Germany/ France it is 25Kgs. Is the LMA looking into standardising with Europe on this 25 Kgs limit?

Tim, the 20kg UK limit is a dry weight, the German/French 25kg limit is the wet weight, (IIRC, as most of continental Europe follow the US AMA's 55lb wet weight limit). It does mean that our models can be over 25kg wet, although that's a heck of a lot of fuel


Mark

[Shaun Garrity]

Hi,
This question is directed mainly for Tony.
re the following statement..
"

So long as we keep to the criteria established with the CAA which I have referred to above when approving Over 20kg radio installations then there should not be any problems. Inspectors simply have to ask themselves this question about a specific installation "If a Rx or a battery fails is there sufficient limited control to enable a controlled landing to take place away from danger"

From reading the posts, A weatronic twin Rx system is an accepted solution to meet the over 20Kg requirement. This system comprises basically of 2 receiving systems outputting onto a single set of servo plugs.

Consider this..so does the cheap full range 6 channel Spektrum AR6200 or AR7000... one onboard Rx and a satellite Aerial ( Rx), so if the Weatronic is an acceptable solution for the over 20Kg requirement, then the AR6200 is. (dual battery & current limitations for the servo's aside).

However both systems have a single point of failure, so clearly don't meet the requirement to provide limited control as a failure in the decoder section means no output, no control.
(The main reason for the multiple aerials on any 2.4g system is due to the directional nature of higher bandwidth transmission...They are there to provide an improved RF environment ..to improve path diversity. I don't believe they were ever conceived to be considered as seperate Rx systems).

So If the LMA allows the Weatronic dual Rx system as an acceptable solution, then a single AR6200 or AR7000 meets the same radio criteria by default, but neither would allow limited control in the event of a decoder failure as a true dual RX installation would.

The question is then are we saying that it is, an acceptable solution to have a single point of failure as the Weatronic and Dual Rx with an RRS system provide or even a basic AR6200 . 7000Rx ?

Clarification and hopefully conclusion of this post please Tony ??

Shaun

[tony hooper]

Shaun (and all)

It is obvious from the number of contributions and "hits" on this thread that it is a topic of great interest - and rightly so. Phil Clark really set things going with his rather "innocuous" posting.

In attempt to "close off" this thread as requested in Shaun's last message could I set out the following :-

a. The introduction in the UK of 2.4Ghz has raised a number of issues which are significantly different to the well tried and tested Over 20kg 35Mhz systems. For instance, most modellers appreciate that even on Under 20kg models it is far safer to have 2 batteries rather than one in respect of 2.4Ghz installations due to the fact that the voltage tolerance on 35Mhz was much better (please do not start a new thread on this!).

b. Under the 35 Mhz regime no particular manufacturer or installation has ever been LMA "approved" although our past Chairman Keith Mitchell did produce an excellent guide on some of the aspects that could effect certain aspects of installation. With 2.4ghz we have to adopt a similar level of "universitality" about systems.

c. It has always been the LMA policy to ensure that any builder of an Over 20kg model is given an appointed Inspector who will discuss the building requirements and listen to any suggestions or solutions to problems which will effect the final product. Our inspectors are not technical "wizards" but do their best to ensure that the LMA retains a safety record which the CAA will endorse by their continued commitment to our administration and supervision of the Over 20kg regime.

d. We must bear in mind that no system is completely "fool proof" and I refer you to an earlier posting which emphasised that the on board installation is only as reliable as a TX crystal or module. Even full size aircraft with triple systems have failures , sometimes with horrendous outcomes. Our task is to ensure that we not only have system installations which reduce the risk of failure as much as possible but are also combined with an attitude to flying safely within the guidelines set out by the BMFA, LMA, and in the case of Over 20kg models , the CAA restrictions contained in the "Exemptions to Fly".

I hope this now closes the thread but I would like to thank all those who have contributed - healthy and challenging discussions are good "for the soul".

[Simon Willey]

I feel this thread is not really at an end. I don't see that many of the points brought up have been addressed yet.
Just a few of my views on Tonys post

It is obvious from the number of contributions and "hits" on this thread that it is a topic of great interest - and rightly so. Phil Clark really set things going with his rather "innocuous" posting.

How was his question innocuous. It was a perfectly reasonable question from an LMA examiner , and one that you did not answer correctly.

a. The introduction in the UK of 2.4Ghz has raised a number of issues which are significantly different to the well tried and tested Over 20kg 35Mhz systems. For instance, most modellers appreciate that even on Under 20kg models it is far safer to have 2 batteries rather than one in respect of 2.4Ghz installations due to the fact that the voltage tolerance on 35Mhz was much better (please do not start a new thread on this!).


Why is it safer to have two battery's instead of one on 2.4. Please explane. Why not start a thread on it as I would think that there are a lot of people with valid points on this subject . Why don't you want a thread started on it. You must have views on it or the LMA must have views on it. This knowledge should be past on to others wishing to learn. That is what this forum is all about. Is not that what it is set up for.


Under the 35 Mhz regime no particular manufacturer or installation has ever been LMA "approved" although our past Chairman Keith Mitchell did produce an excellent guide on some of the aspects that could effect certain aspects of installation. With 2.4ghz we have to adopt a similar level of "universitality" about systems.

Surly 2.4 is not that new any more. There are a lot of people who have been using it for a number of years. . If you have allowed its use on large models then you must have a set of guidelines to follow as you must have had on 35Mhz. You must have done a lot of testing. You should surly know the answers to most of the questions raised in previous posts about Spektrum RXs after all you are the LMA safety officer . Surly you would have these facts to hand .

c. It has always been the LMA policy to ensure that any builder of an Over 20kg model is given an appointed Inspector who will discuss the building requirements and listen to any suggestions or solutions to problems which will effect the final product. Our inspectors are not technical "wizards" but do their best to ensure that the LMA retains a safety record which the CAA will endorse by their continued commitment to our administration and supervision of the Over 20kg regime.

I understand that an inspector will be looking over the set up in a model. When one of the inspectors asks you a question regarding a piece of equipment I would expect he would be given the correct answer. I do not expect anyone to be a Technical "wizard" but you have the resources to get the information.
There must be guidelines. Why not put them on the site. Give proper examples of set ups in different models .


I hope this now closes the thread but I would like to thank all those who have contributed - healthy and challenging discussions are good "for the soul".

It would be a shame if this thread closes. I think there is a lot of useful information out there , that can be passed on.
Surly that is the idea of this forum. To pass on information to help others out and the future of our hobby

Regards Simon

[Shaun Garrity]

Hi Tony,

I have to agree in part with Simon....
Very few of what I believe my important questions were answered.
But mainly.....
Are the LMA saying that 2 Rx's driving 1 decoder..as in the Weatronic and virtually all spectrum Rx's ( dual power and Rx current considerations aside) acceptable as an alternative solution to the Dual independant Rx solution.....

I'm asking because if it is , it will save me (and many other modellers) a fortune when I finally take the big plunge or put far too much silver paint on my 1/3rd scale Nieuport 17 in airbourne hardware costs, but still provide an acceptable safe solution..

Whilst I appreciate this is not an easy question to answer, I believe it needs serious consideration and direction from the LMA to guide us and give the inspectors a level playing field as opposed to personal preference to work from.

Thanks in anticipation

Shaun

[IVAN GOODCHILD]

As many members will know I did the orginal technical appraisal of 2.4 systems for use in over 20kg models for the LMA. As a result of the position the committee has taken todate there have been no incidents where a model has not complied with the CAA guide lines "Upon the failure of any single point in the airborne control system, the model should still have sufficient control to enable a controlled landing to take place". Taking the installation guide lines in Keith MItchells booklet regarding 35MHZ and replacing the receivers with 2.4 ones, everything else remains the same has again proved the test of time. I will try and keep the following as simple as possible. Indeed with 12 channel receivers now available with transmitters to match one has to ask why are members wanting to instal complicated systems in relatively simple models. KIS still applies. Members are still getting confused with the word receiver. When satellite receivers are used these are just RF modules which via serial data links provide data to the same single controller. The controller decides which of the satallites to take notice of and hence what signals go to the servos.
So there is redundancy in the RF side but not in the controller or servo drivers.

I know the family at Power Box very well, and turning to the very first post. The unit contains ONE master receiver and requires at least one satellite to maintain signal validity. There is only ONE controller handling the data from the "receivers" as it is not possible to fit two without some very sophisicated software which we use in the commercial world, and loss of a few channels. The output stages to each of the matched output servos are individually set so any failure of one will not affect the others. The power supply does have dual systems throughout.

The installation of one of these units in an over 20kg model does NOT meet the technical requirements of the CAA guidelines and Power Box actually recommend the use of their RS system which does meet the requirements and which I can confirm Tonys comments that they have been well and truly tested in UAVs

[Shaun Garrity]

Hi Ivan ,

thanks for the detailed and informative response.

So, based on what you have posted, which confirmed my understanding of how multiple Aerial Spektrum receivers work, this means that the twin Rx weatronic systems also do not meet the CAA requirement for over 20Kg models, as they also have a single point of failure again where the 2 receiver RF outputs are multiplexed internally together to provide the servo outputs.

Members are still getting confused with the word receiver. When satellite receivers are used these are just RF modules which via serial data links provide data to the same single controller. The controller decides which of the satallites to take notice of and hence what signals go to the servos.
So there is redundancy in the RF side but not in the controller or servo drivers.

Based on that are any over 20Kg models currently approved for flying with a weatronic system in, if so, have I misunderstood how the Weatronic system works?

Regards,

Shaun