Model Restraint

[Masher]

I don't understand what Erfolg is on about

I fly electric and IC but my preference is IC

In my club there are no rules to say electric models must be restrained whereas IC must always be restrained. I am Ok with this as long as the throttle is not applied until the model is in the take off position. Unfortunately we have some people who seem to think it is Ok to test their electric models in the pitts and even at the clubhouse/car park! There are even people who "drive" them around where they sit to check they travel straight!!! At only 57 and still an improver, I am the "young upstart" unfortunately so my concerns seem to be laughed off as irelevent. I will be raising this at the next club night as unacceptable practice (for my own safety)

We also have people (much more experienced than me) who will not fly IC alone because they feel IC are too dangerous yet they are happy to fly electric alone. The only sensible answer I have received as to why is - IC is more likely to trow a prop. Whilst this may be true, an electric motor can be more lethal. At least an IC prop will stop - although it does hurt a lot!

This is where the BMFA should perhaps be more specific and suggest rules and typical acceptable restraints

[Ted]

Masher welcome to the "Utterly confused" post. Nobody but Erflog knows what it is that he is trying to say so don't worry about it, no one else is. Ted

[Greybeard]

All models that have an engine running or capable of running and able to cause injury should be mechanically restrained; there should be no distinction between the motive power employed. Relying on someone holding the model is daft because if something goes wrong the assistant is the first to run; that’s something that has been discussed here before.

[crispin church]

if your on 2.4 and set your fail safe correctly then just turn off your tx if no switch / safety plug on outside of plane or on my DX6I i replaced the cut off button with a switch so i flick the cut off switch

but at end of day any model that could shoot across patch should held back by some thing

[Greybeard]

Posted by crispin church on 03/08/2013 09:36:52:

if your on 2.4 and set your fail safe correctly then just turn off your tx if no switch / safety plug on outside of plane or on my DX6I i replaced the cut off button with a switch so i flick the cut off switch

but at end of day any model that could shoot across patch should held back by some thing

There is normally a delay between switching off and the fail safe activating so this is most definitely not a good idea.

[John Privett]

Posted by Erfolg on 02/08/2013 21:43:07:

Come on, you sound like an IC man

Argggghhhh.... At least I see I'm not the only person getting frustrated at your constant attempts to divide model flying into electric and IC and somehow demonize the IC'ers.

I fly both. I see restraint of models as an important issue. Not just to stop an out of control model hitting somebody who was in front of it starting the IC engine, but to stop it hitting anybody else as it charges across the field - maybe in a huge circle back to the pits? And that applies equally (perhaps more so) to electrics as to IC.

One restraint is not going to fit all. Models without an undercarriage (notice I don't give a hoot whether it's electric or IC) will not be restrained by the same method that a model with an u/c will. Electric/IC - that's not the issue.

[Concorde Speedbird]

Well said John!

CS

[Erfolg]

I had hoped that an enterprising modeller had come up with a restraint or restraints, which were targeted at the characteristics of electric flight.

I do think that will become more of an issue as electric models become more powerful.

I do notice and do not apolagise for observing that there is a fundamental differences with electric models, there is no need to be in front of the propeller, or to the side, when arming or operating and should not happen. This is a significant difference in establishing safe operation.

Then there are some myths which continue to be peddled. That is electric propellers will not stop. Only last week I witnessed a 800w electric inrunner with gearbox, with the throttle opened, on the ground. As the model was not my own I was as interested in what would happen next. The throttle was quickly closed, the model and propeller twitched as the stalled propeller sort to turn. I have seen a number of models in similar circumstances, with similar results. I have even seen a model that was left with apparently full throttle after crashing. The result was a burnt out ESC, possibly Lipo damage, although I do not know. The point is that some of the predictions may happen, although the majority of the evidence suggests otherwise. From this it seems that restraining the propeller can be beneficial in some respects, although the downside is potential equipment damage. In some quoted cases I do wonder if the reporter wants to blacken and exaggerate perceived dangers.

I really want the generally good safety of electric flight to be maintained, and improved if real benefit can be gained.

What I do not want to see is a set of requirements imposed that are appropriate to IC models, on the basis that "one size fits all".

In principal the idea of "requiring restraint" is the way to go. For me the question is next question is "what is a suitable" restraint.

I have given up on there being immediately any restraints specifically electric models, as there are for IC models. A major difference the features are understood, that the model cannot be allowed to move forward, as the operator is there during the start up procedure. This is not the same for electrics, no one should be there. I simply restraining the model via the operators legs sufficient? Are there issues with respect to turning a model over, as many models have the Lipo hatch underneath, or is this safe, just requiring a controlled operation? How should you handle a plug in nose and power train assembly?

I had hoped for some good ideas, to copy.

[Martin Harris - Moderator]

I'll second that John - CS, your post was wise beyond your years and should be an example to many of those older and greyer than you.

Having said that, the point I believe Erfolg is trying to make is that while an electric model is being readied, there may well be a period that it is being handled in a "live" condition, analogous to starting an IC model inverted and turning it over with the engine idling. I do concur that any model which has a live propeller poses a real potential danger.

You're a (retired) engineer Erfolg - why not spend some of your idle time designing something to overcome the perceived problem?

Or adopt Martin P's approach to external isolation and put it in a universal restraint before finally arming the model.

(composed during Erfolg's reply above)

Edited By Martin Harris on 03/08/2013 14:11:20

[Foxfan]

I have carefully developed a restraint system over many years which works for all kinds of models. It's been snappily named the "Tight Wad". It restrains me from making any purchase that might result in my turning up at a club with a model and is very effective!

Sorry, I obviously have too little to do on my holidays!

Martin

[Greybeard]

Posted by Foxfan on 03/08/2013 14:29:48:

I have carefully developed a restraint system over many years which works for all kinds of models. It's been snappily named the "Tight Wad". It restrains me from making any purchase that might result in my turning up at a club with a model and is very effective!

Sorry, I obviously have too little to do on my holidays!

Martin

Obviously!

[Erfolg]

Martin, all my best ideas and designs have been borrowed (or is that pinched) from others. All successes were and are due to my brilliance.

The point with all design, is actually clearly understanding what the issues are. At the same time I found that managing safety, was in principal the same.

I am not being critical of others, although I have noticed that many things done, have inherent dangers, that because they have not realised, have passed by, as unnoticed. With small models, the degree of danger is minimal, as models have in some cases reached sizes with significant power, the potential for damage has risen. A little like the difference between a thimble of water and a bath of water at 100C.

I am also aware that some of the reported events are difficult to see as being credible. Either the person is incompetent, or is, reporting what they think would happen, as many bare no correlation with actual real operational incidents, Which none the less has enough real risks. To overcome this, i expect that the BMFA will or are accessing the real issues and how to manage them, in a measured and proportionate manner.

I have been wondering for some time (in a absent mind way) now that I have joined an IC club, if it is not better to deliberately, ensure that the propeller is in a stalled position, where it cannot rotate as is the norm at the electric club. I am not saying it necessarily is, as with a electric model, procedures should ensure no one is near the prop. Maybe it does not really matter, being a case of swings and roundabouts. There are many issues which can be considered different to IC issues. Probably in the pit area more differences than commonality.

In the meantime I was hoping some ideas were kicking about.

[Phil 9]

Erfolg what features would you electric restraint have that existing types of restraint do not have? I am at a loss.

Maybe a decal that reads “ELECTRIC MODELS ONLY”

[Erfolg]

Phil, it is a issue of adressing features from the standpoint of what is required for electric models. Only then consider what exists for other uses, which could be used.

I see a problem in that it is not clear, well not to me, what is actually needed, for electric models.

I can see that for electric models it is possible to argue, reasonably, what is wrong with restraining using your legs, whilst standing astride the model? So what if the model moves forward, no one is in front, there is no safety issue if the model moves forward. It is not moving into a crouched form hudled infront.

But is that the only issue?

[Concorde Speedbird]

Thanks for the compliments Martin!

If you feel that this is another thing that should be available in electric or IC versions (which I don't think it can) then what next? It is almost as if some people wish that the hobby is separated into two different camps, but surely one of the main aspects of this hobby is that we have variety, so you can create whatever model you wish and you can use different power sources. There is no need to influence the hobby so that you have to get certain equipment just because your model is electric/IC, because at the end of the day it makes it more expensive and time consuming for everyone, when you can perfectly safely use equipment that is already there.

They both do the same job, so therefore they can both be restrained in the same way, as they have been without issue. So for me this thread doesn't underline an issue, and is just a vague discussion in a problem that isn't there.

What I would like to know is a comment on what I and John have highlighted in earlier posts about trying to divide aero modellers into 'IC and electric people', as if we are two different species when in fact many use both and we all have similar interests- flying aeroplanes.

CS

[Martin Harris - Moderator]

This is in danger of reawakening an old discussion and going rather off topic but I'd just like to agree that there shouldn't be any great divisions between those who like to fly i.c. or electric.

Apart from the dangers to the hobby in general of divideing and conquering, I just feel that excluding any form of modelling means people miss out on a great deal in the hobby. I really hate seeing or hearing people villifying either form of propulsion - even if I must admit that I still drop the occasional jokey comment to friends who I hope realise they are made in jest.

In days gone by, electric flyers were often teased due to short and rather asthmatic flights with lightweight models and perhaps this is why some seem to be fiercly anti-i.c? The pioneers have driven, with the aid of power-hungry applications such as mobile phones, the technology which makes e.p. so practical these days. Although I often fly electric models, I would still hesitate to commit a great deal of effort to a scale model that didn't have a "living", fire-breathing engine but if someone decides to produce an e.p. model, I'll enjoy watching it fly and admire the build, even if (to my mind) there's something missing.

Back on topic, it seems to me that for e.p. models should be designed for safe operation using existing simple restraints. Trying to design a "one size fits all" system is likely to result in a complex solution, which while it could undoubtedly result in an intriguing and admirable example of clever design and engineering, would most likely present unexpected hazards while in use. Much better to use the simple tried and tested designs favoured by the average club flyer coupled with a well thought out model design.

Edited By Martin Harris on 03/08/2013 19:28:32

[Concorde Speedbird]

Yes, that is all correct, I completely agree. Well said.

CS

[SkippyUK]

Getting back to original post and trying to itemise the 'ideal' restraint it should allow the following;-

1. Must reduce/stop any forward motion of the plane when starting IC or installing/arming from above (say 150mm/6" ).

2. Must allow model to be picked up, turned over, shaken and stirred while still restrained

3. Must be easy to both attach and remove from model

4. Must not cause undue damage to model or finish in normal use

5. should ideally be usable on tarmac or grass surfaces

 

Taking all these things into account, one possible solution might be a strap type restraint around the tail plane (with suitable soft covering to avoid damage) attached to say a2m/ 6' long lanyard secured by either stake or heavy weight according to available power and type or surface.

This would allow the plane to be picked up, turned over etc. while still restrained and if the motor did start full chat while being handled, the worst would be anyone/anything within a 2m +plane length sphere although I would expect a dropped plane to just end up with a broken prop at your feet but I suppose it's possible for it to try to go vertical........

I don't own one but have seen many belt/strap type restraints but none with a 2m long lanyard to allow the plane to be picked up but someone may know if a commercial solution already exists.

 

Skippy

 

Edited By SkippyUK on 03/08/2013 21:25:05

[Erfolg]

This morning I was observing a F3b(e) being readied for launch, when I think I saw the answer to electric flight safety requirements. Probably mentioned in this thread by at least Martin and probably another.

That is the use of an arming plug, which is only inserted immediately prior to launch. Deleting the need for any form of restraint, other than necessary by (the pilot) holding the model when readying for flight. The model had a lot of work undertaken on the power pod, in complete safety. As the height cut out was adjusted, data logger worked on, before connecting the lipo. The whole lot plugged in the front end, then secured. Only when readied for flight was the arming plug used. Preflight checks made by the pilot, while the launcher held the model, all accomplished in complete safety (with respect to any credible issues).

I had previously seen arming plugs based on 3.5mm connectors, which tend to be cumbersome, and ugly. Todays was an improvement on the same idea, based on a Deans type plug, this was visually an improvement, whilst retaining the functionality. I am now wondering, is there a propriety version that is even better from the installation, visual, and retaining the important safety function.

So perhaps, with the use of arming plugs, there is no basis for the use of any restraint. On this thought a better mousetrap, is the one called arming plug, not a restraint.