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Member postings for Martin Harris

Here is a list of all the postings Martin Harris has made in our forums. Click on a thread name to jump to the thread.

Thread: Forum members' new models: Let's see them.
25/03/2019 16:41:00

Almost a shame to cover it!

Thread: South Herts Glow Switch
25/03/2019 15:57:46

On their way...

25/03/2019 15:34:28

Which version - the earlier single cell or the later 4 cell AGS version?

Edit: I've just checked and I have both downloaded - PM me your email address and I'll send you them...

It's a shame they have gone - it was only in September of last year that I downloaded the AGS handbook "just in case"...

Edited By Martin Harris on 25/03/2019 15:49:23

Thread: Forum members' new models: Let's see them.
25/03/2019 15:25:45

I do know your views on on-board glows Jon - hence the smilies! I've used them on scale models for convenience in starting and I like the idea that a dropped cylinder should restart on a multi but you do need to set the engines up with them disabled to avoid masking any set-up issues...I suspect we should agree to differ?

Anyway, back on topic, over the last few weeks I've been building a replacement for my late lamented Extra Slim Twin which made a large dent in Hertfordshire well over a decade ago.

Slim Twin

RIP!

After finding an Extra Slim kit and squirreling away a couple of new/almost new OS 46AXs along the way, I located my old plans and duplicated the necessary fuselage components. They were slipped into the box which lurked in my loft for several years until the urge came upon me this year...

20190325_141539.jpg

The replacement awaiting its maiden later this week...

The first one flew OK on its original SC25s, better on a pair of OS 40FPs and rather well on a slightly mismatched pair of ball raced OS 40s - I'm anticipating "more than adequate" performance with the 46AXs. Dick Dastardly and Muttley (who has gained a new medal since the loss of the previous version) will resume their duties and I suspect the pigeon will need to flap its wings rather harder now!

20190325_134252.jpg

No plans to add on-board glows to this one!

Covering is Hobbyking polyester film - I was very impressed with the way it went on - and the very reasonable cost compared to Profilm/Oracover which I know and love. The chequered underside (a departure from my original colour scheme) would have cost an arm and a leg to do in Oracover. The only significant difference appears to be the backing paper which is a pig to remove - Oracover being particularly easy in this respect.

25/03/2019 13:09:25

Posted by Jon - Laser Engines on 25/03/2019 12:15:53:

It only dropped cylinders when i went all the way back to idle in a fast dive so i wont be doing that again!

Perhaps you should have fitted an on-board glow driver! cheekydevilembarrassed

I suppose it does raise a point though - full size practice in glider towing was always to descend with significant power to avoid shock cooling the engine and cracking cylinder heads - have you ever come across evidence of model engines suffering similar damage?

Last time I saw that engine it was in a sorry state on your bench - great to know that you've managed to resurrect it - something I'd love to own but would struggle to justify the cost...

Thread: New Drone/Aerodrome Regulations - Is your club at risk?
24/03/2019 11:04:17

I suspect there may have been a recent update to the ANO which may cover the situation at locations such as Old Warden?

Whilst perusing the ANO (as you do!) I noticed the following

Small unmanned aircraft: permissions for certain flights94A.—(1) If the permission or permissions that are required under this article for a flight, or a part of a flight, by a small unmanned aircraft have not been obtained— (a) the SUA operator must not cause or permit the small unmanned aircraft to be flown on that flight or that part of the flight, and(b) the remote pilot must not fly the small unmanned aircraft on that flight or that part of the flight.(a) Amended 2017(b) Amended 2017(c) Amended 2019(d) Amended 2017

50(2) Permission from the CAA is required for a flight, or a part of a flight, by a small unmanned aircraft at a height of more than 400 feet above the surface.(3) But permission from the CAA is not required under paragraph (2) if— (a) the flight, or the part of the flight, takes place in a flight restriction zone at a protected aerodrome, and(b) permission for the flight, or the part of the flight, is required under paragraph (4) from an air traffic control unit or a flight information service unit.(4) Permission for a flight, or a part of a flight, by a small unmanned aircraft in the flight restriction zone of a protected aerodrome is required—(a) from any air traffic control unit at the protected aerodrome, if the flight, or the part of the flight, takes place during the operational hours of the air traffic control unit;(b) from any flight information service unit at the protected aerodrome, if the flight, or the part of the flight, takes place during the operational hours of the flight information service unit and either— (i) there is no air traffic control unit at the protected aerodrome, or(ii) the flight, or the part of the flight, takes place outside the operational hours of the air traffic control unit at the protected aerodrome;(c) from the operator of the protected aerodrome, if— (i) there is neither an air traffic control unit nor a flight information service unit at the protected aerodrome, or(ii) the flight, or the part of the flight, takes place outside the operational hours of any such unit or units at the protected aerodrome.(5) In this article, “operational hours”, in relation to an air traffic control unit or flight information service unit, means the operational hours— (a) notified in relation to the unit, or(b) set out in the UK military AIP in relation to the unit.(6) In this article and article 94B, “protected aerodrome” means— (a) an EASA certified aerodrome,(b) a Government aerodrome,(c) a national licensed aerodrome, or(d) an aerodrome that is prescribed, or of a description prescribed, for the purposes of this paragraph.

OK - not very readable, but if I'm not mistaken, the important part is

(c) from the operator of the protected aerodrome, if— (i) there is neither an air traffic control unit nor a flight information service unit at the protected aerodrome, or(ii) the flight, or the part of the flight, takes place outside the operational hours of any such unit or units at the protected aerodrome.

Thread: Jamara spares & West Wing Kits
22/03/2019 18:45:39

Might be worth giving Ali a call? **LINK**

Thread: Does your club prohibit the use of after-market receivers?
22/03/2019 14:25:05
Posted by stu knowles on 22/03/2019 13:18:41:

Nor do I think that the BMFA have made any proclamations on the subject

But they have!

The clubs' representative, Andy Symons has stated categorically and publicly that "There is not an issue using mix and match TX/RX" and reinforcing that operators "should ensure all necessary checks are carried out to ensure equipment operates correctly."

Of course a club can make rules as it sees fit as long as they comply with any legal responsibilities but there is NO justification in quoting the BMFA as having specified or suggested banning responsible mixing and matching.

Thread: NEW POLL - Does your club have a safety officer, or is the emphasis on individual members to each be their own safety officer?
22/03/2019 11:15:53

Interestingly, I just noticed a bit about this in the BMFA Handbook while looking at it on another matter which I'm ashamed to say that I don't recall seeing before.

While I understand and endorse the concept of encouraging personal thought and awareness of safety issues, the BMFA position is clearly against the "every member is a safety officer" approach!

(My italics)

11.3 The Club Safety Officer
If it is considered to be appropriate, a Club should appoint a competent CLUB SAFETY OFFICER whose duties would be to ensure that both the BMFA and the Club Safety Codes are followed.

However, a Safety Officer acting alone has an almost impossible task and some form of infrastructure should be set up within the club to help the designated officer.

The most successful way to do this is to make the task of Assistant Safety Officer part of the duties of every Committee member. These Assistants then report to the designated Safety Officer when required. This will keep the Safety Group to a manageable size but will ensure that there is a recognised safety presence at most flying sessions.

If it is felt that this might not be enough, you can appoint other responsible club members as assistants too. Examiners, Instructors or senior club members might all be candidates.

It is not recommended that you appoint ‘all club members’ as their own safety officers. Such an approach loses the focus of a smaller group and can become ineffective.

Clubs should educate and encourage their members, particularly new or junior members, to conform to Club safety requirements and should have no hesitation in disciplining persistent offenders.

Edited By Martin Harris on 22/03/2019 11:20:00

Thread: Does your club prohibit the use of after-market receivers?
22/03/2019 00:00:51
Posted by Charles Smitheman on 21/03/2019 21:17:48:

15.14 Mix-and-Match Tx and Rx Using different makes of transmitter and receiver is common practice when using 35 MHz equipment, especially with the large range of aftermarket receivers available. There is a point you must be aware of, however, concerning manufacturers guarantees. A matched Tx and Rx will be warranted by their manufacturer both as individual items and to work together as a pair. If you ‘mix and match’, the individual warranties still apply but you have no guarantee that the pair will work together. In this case you take upon yourself the legal responsibility of making sure that your equipment operates correctly.

Above excerpt from the BMFA Members Handbook.

Make of it what you will. But if it all goes pear shaped, am I covered by BMFA insurance or not?

How could I legally prove that I have made sure that the equipment works or worked when tested? Signed documents from witnesses to a range test?

And in what way is this different from like for like RX/TX .I still have to ensure that they are working before flight.

I do not see how this is different to any other part of a model aircraft. Why has the BMFA singled it out?

I as the operator am responsible to ensure that the flight can be safely carried out.

It's all one long chain of command with many possible pitfalls!

I believe the wording of the relevant articles include such phrases as "reasonably certain, recklessly and negligently". None of these support any absolute action in the event of an accident and the onus should be on the prosecutor to prove any negligence or criminal intent should they feel there was a gross dereliction of responsibility on the part of the model's operator.

If someone is affected by this issue and wishes to continue using their receivers at their club, I would suggest a formal request to the club's committee (especially if there are like minded fellow members who would add their support) perhaps quoting some of the opinions (especially the BMFA quote) within this thread, for a review of the policy along with evidence that their action can be justified should they feel that the rule must stand. As a committee member of my own club, I would have no qualms about responding to such an approach - and I would hope any committee worth its name would take the same attitude as they exist solely to represent the interests of their membership.

 

Edited By Martin Harris on 22/03/2019 00:04:34

Thread: NEW POLL - Does your club have a safety officer, or is the emphasis on individual members to each be their own safety officer?
21/03/2019 13:34:42

For my sins, I am currently the safety officer for my club. We try to encourage individuals to think about their operating practices and I feel that my duties are primarily to offer advice, either at the field or via the club newsletter. On the rare occasion that someone does something blatantly unsafe, I have a quiet word with them about what I feel is unsafe and how they might operate more safely and I have yet to take any further action.

I do not possess a high vis jacket!

Thread: 104 inch B-17 Identification
21/03/2019 13:27:21

...and the cheapest and easiest to duplicate!

Thread: Does your club prohibit the use of after-market receivers?
21/03/2019 13:20:43

That reminds me of when I was at a big club event (more of a public display than a fly in) in Germany and after an incident with a large model and demonstrated reproduction of the problem, the organisers banned flying any models using the newly released 2.4GHz system of an exceedingly respected German radio brand (since replaced with a different system).

I heard no complaints other than at the manufacturer's decision to use a bought in protocol. Quoting them would break at least two forum rules!

P.S. The receivers being used were genuine originals from the transmitter's maker...

Edited By Martin Harris on 21/03/2019 13:25:30

20/03/2019 22:11:28
Posted by Andy Symons - BMFA on 31/08/2018 12:59:16:

There is not an issue using mix and match TX/RX however you should ensure all necessary checks are carried out to ensure equipment operates correctly.

I hope it's OK to copy this response from Andy Symons from Tony's original thread - hopefully it should end any speculation that the BMFA has proposed or endorsed any ruling or suggestion that third party receivers may not be used - or that the insurance has any bearing on the matter.

Thread: Castor oil in 4 stroke engines
20/03/2019 21:41:42
Posted by ASH. on 20/03/2019 18:31:19:

Does anyone know or have any info on ML70? I'm thinking of switching from Klotz.

I believe it's the oil used by Southern Modelcraft which I've used since 2002 with excellent results. The 10% nitro mix that I use in virtually all my engines does contain 2% castor (and 15% ML70) and I haven't suffered from any noticeable carbon build up or varnishing.

Edited By Martin Harris on 20/03/2019 21:50:59

Thread: Does your club prohibit the use of after-market receivers?
20/03/2019 18:25:32

Was this based on any particular experiences, Tony? I'd be interested to know the justification if you were party to the discussions.

Have they also banned cheaper less well known outfits with unknown resources behind their development and production? Unless there have been well documented and confirmed problems with any unmatched combinations, wouldn't they present at least a similar risk?

Given the numerous reports of transmitter problems from a very well known manufacturer, almost routine replacements of RF boards and reported weaknesses in their original spread spectrum implementation, has your club banned them (or their early versions) too? I suspect that the many satisfied users of that system at my club would be rather unhappy if we took that line, notwithstanding that it could be argued that there is at least as much justification to do so than to ban the (very common) use of third party receivers!

Edit - seems that your reply overlapped a little.  Is your club BMFA affiliated or do you use a different insurer - as far as I'm aware, BMFA insurance does not impose restrictions as to the makes or quality of radio gear used.

Edited By Martin Harris on 20/03/2019 18:28:45

Thread: 104 inch B-17 Identification
20/03/2019 14:39:25
Posted by Jon - Laser Engines on 20/03/2019 08:44:42:

In the instructions for the herc it recommended to set up the throttles on two channels so the inner and outer engines could be controlled individually. The theory was that if one engine stopped you would kill its best mate. This struck me as daft as you are turning the loss of one engine into the loss of two. If another drops you are really screwed! The only time i would consider killing the engines on a 4 engine model it would be if i lost two engines on one side. I would try and keep it flying, but i would be prepared to cut it.

Maybe they meant that you could idle the remaining engine rather than kill it, preserving balance while keeping the good engine in reserve?

I think Chris's question really pertains to the number of functions available from his transmitter. In this case, I could see a case for a co-pilot operating flaps, undercarriage, lights, bells and whistles via a separate transmitter.

From experience of twins, it is good to have isolation for the throttles for starting and ground running - you don't really want all the engines roaring away while you're making adjustments on one of them. Sadly, Chris's transmitter is unlikely to be able to accommodate that even if the non-flight functions are given to the co-pilot.

Thread: Does your club prohibit the use of after-market receivers?
20/03/2019 14:26:14

Not at my club. However, should there be a demonstrated problem then it would be an option.

If we were driven by largely unsubstantiated reports of problems, we'd have banned one of the most popular brands many years ago!

Edited By Martin Harris on 20/03/2019 14:26:37

Thread: Castor oil in 4 stroke engines
19/03/2019 16:43:46

I thought that perceived wisdom was that petrol has a lubricity that methanol doesn't have. Would the percentage not need to be slightly greater for glow or is it another old wives' tale?

Thread: Connecting two batteries in a model.
17/03/2019 14:58:48

At one time it was common practice for battery makers to assemble packs in parallel - designations such as 4000 4s2p denoting a pair of 4s batteries paralleled together (with the balance leads also connected in parallel internally coming out as a single lead/plug).

I have 2 4000mAh Rhino packs configured as above which are donkeys years old and have seen very regular service in a model used as my go-to hack for most conditions - they still give over 3600 mAh with plenty of reserve after several hundred cycles (I habitually fly them in a telemetry equipped model which alarms at this point although they are still producing good power) so parallel charging does not appear to have harmed them at all.

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