Don't test fly on a windy day - you'll probably regret it!

[Dickw]

If you are operating commercially under CAP722 the reporting requirements are in section 2.9 of that document - e.g.

Operation of the aircraft
• Unintentional loss of control
• Loss of control authority over the aircraft
• Aircraft landed outside the designated area
• Aircraft operated beyond the limitations established in the relevant operating category or operational authorisation

The "beyond the limitations" bit would include beyond visual line of sight i.e. a fly away, unless you have separate CAA authorisation for BVLOS.

That reporting requirement is certainly in our Article 16 Authorisation, so it is reportable whichever way you operate.

Dick

[Dickw]

Posted by Martin Harris - Moderator on 29/01/2021 14:11:56:

Bonzo - are you a member of the BMFA? If so, it would be best to call their office for advice/guidance on incident reporting.

Just to clarify Dick's point, Article 16 applies ONLY to members of the organisations granted priveleges.

Just to be absolutely clear, the Article 16 Authorisation only applies while you are operating within its terms, and BMFA (or other organisation) member or not that excludes any form commercial operation.

A BMFA member flying for any form of payment would need to be operating under CAP722 terms and would probably need separate insurance.

Dick

[Martin Harris - Moderator]

In terms of safety, incident reporting and a very lightweight model, the video suggested little in the way of potential for serious injury or damage but many of us are painfully aware that negative impressions could potentially damage the hobby.

While the moderators respect the right of individuals to interpret laws and regulations, make personal judgements and potentially test them in a court of law, our personal advice would be that as a responsible community we should not be looking for ways around legislation intended to protect the public from the spreading of the current pandemic.

I think enough has been said on the wisdom or otherwise of posting the video, which I'm sure was done with the best of intent.

It would be appreciated if further comments or suggestions were confined to the problems encountered in flying that particular model and we should all be heeding the sage advice that flying conditions need - and in fact require by law - pilot consideration.

Martin Harris

Moderator

Edited By Martin Harris - Moderator on 29/01/2021 15:26:26

[ken anderson.]

bit harsh there Martin,fair enough your the mod and you have the final say. But this thread like most has drifted off from the original question and gone on to look at the bigger picture of what was described as happening on the day and the following day looking for the wayward model.

I don't see any breaches of the COC etc, the original posting has expanded into a general discussion, that's all.....

ken anderson...ne..1....general discussion dept.

[J D 8]

Coming back to the actual model/flying. Given that in the second video the model started doing what it did in the first video, that is uncontrolled prop hanging. Could it be that the battery slipped back ?

[Rich Griff]

I'm still a tyro and learning all the time.

Please could someone tell me what size are the identification letters and numbers and how many make up the identification code please ?

The identification info that is supposed to be on RC flying models these days. Thanks.

[Martin Harris - Moderator]

3mm high minimum - legible typeface and if not appropriate e..g. for a scale model, accessible to check without tools.

[Rich Griff]

Thanks, so they will fit on my s/s, powered glider and powered RC converted f/fight found, and 4 channel powered fixed wing shadow, and the helo as well.

3mm minimum is quite small.

[Bonzo Moon]

Posted by J D 8 on 29/01/2021 16:18:22:

Coming back to the actual model/flying. Given that in the second video the model started doing what it did in the first video, that is uncontrolled prop hanging. Could it be that the battery slipped back ?

I always make sure batteries are well secured. It was velcro fixed plus had a velcro strap around it and through the foamboard fuselage. No way it could slide or fall off.

Looking at the way the model was going from full chat, prop hanging, to zero I think a problem with the throttle channel, as someone suggested elsewhere, or even maybe the ESC, or BEC output, which was rated more than adequately and barely warm when I ran ground tests. Dodgy rx? I will never know.

If there'd been less wind I'd have likely got away with it. My stupid mistake.

3mm high minimum - legible typeface and if not appropriate e..g. for a scale model, accessible to check without tools.

I went to 5 mm

Printed off a sheet with Word, multiple labels and just stick on with clear tape.

Also ....

That reporting requirement is certainly in our Article 16 Authorisation, so it is reportable whichever way you operate.

Dick

Will do!

[leccyflyer]

OBE

Edited By leccyflyer on 29/01/2021 20:27:18

[Piers Bowlan]

Posted by J D 8 on 29/01/2021 16:18:22:

Coming back to the actual model/flying. Given that in the second video the model started doing what it did in the first video, that is uncontrolled prop hanging. Could it be that the battery slipped back ?

I have built a few flying wings or tailless models over the years. As a general observation they usually need a very forward C of G (in the region of 20% MAC and sometimes forward of that). They always seem to need a goodly amount of reflex to compensate for the forward C of G to make them stable in pitch. Finally, plenty of down thrust is usually required, often at least 5 degrees if not more. The model in question didn't appear to have very much down thrust which might account for it's propensity to prop hang under power whilst displaying a respectable power-off glide.

Just my 2p worth.

[Bonzo Moon]

Posted by Piers Bowlan on 29/01/2021 20:34:04:

Posted by J D 8 on 29/01/2021 16:18:22:

Coming back to the actual model/flying. Given that in the second video the model started doing what it did in the first video, that is uncontrolled prop hanging. Could it be that the battery slipped back ?

I have built a few flying wings or tailless models over the years. As a general observation they usually need a very forward C of G (in the region of 20% MAC and sometimes forward of that). They always seem to need a goodly amount of reflex to compensate for the forward C of G to make them stable in pitch. Finally, plenty of down thrust is usually required, often at least 5 degrees if not more. The model in question didn't appear to have very much down thrust which might account for it's propensity to prop hang under power whilst displaying a respectable power-off glide.

Just my 2p worth.

I agree, I'd say all of my previous builds have some down and side thrust, but the plans for this and illustrations of it had no down thrust. Weird? CoG was perfect too, or even a bit nose heavy just in case, on the second test.

It even says in the construction notes here The RimFire 250 motor that the author used was screwed to the motor mount. He made sure that there was no downthrust or side thrust. The O-ring prop saver is the appropriate propeller mount for the belly-lander.

plans

[Piers Bowlan]

With a wing loading of 2.91 Oz per squ ft (as per the build article you linked to), not flying on a windy day is sage advice indeed! The author used a 2S 500mAh setup and a 12g motor, all low power stuff. I think if using a higher thrust setup some down thrust is required because of the elevon reflex. I don't think the C of G was an issue either because the glide was good.

[Rich Griff]

So basically stick to what the designer says, not fit a rr Merlin in a mini, dam !

BMC mini not the German thing.

[Martin Harris - Moderator]

Reminds me of Stripteaser back in the day at Santa Pod drag racing (careful how you google it!) meetings. Not quite in the league of a Merlin but the 3.8 Jag running on mostly nitromethane gave impressive performance!

Mind you, there was always the occasional demo run from John Dodd's "Roller" (although Rolls Royce took exception) powered by a Merlin tank engine...I seem to recall reading that although it was road legal, John had to inform the insurance company before every outing.

...so, back on topic, overpowering can make for an interesting diversion but doesn't often result in a sweet handling and practical model.  Great fun at times though!

Edited By Martin Harris - Moderator on 30/01/2021 13:21:41

[Bonzo Moon]

Posted by Piers Bowlan on 30/01/2021 12:20:28:

With a wing loading of 2.91 Oz per squ ft (as per the build article you linked to), not flying on a windy day is sage advice indeed! The author used a 2S 500mAh setup and a 12g motor, all low power stuff. I think if using a higher thrust setup some down thrust is required because of the elevon reflex. I don't think the C of G was an issue either because the glide was good.

Yes, he said his model weight was 6 or 7 ounces. Mine was a little bit more. The motor he used wasn't easy to find and it was expensive, but I used a small one. BR2304 1850 kv. But a few grams here and a few grams there mount up! It wasn't very windy, just a few stronger gusts, I should have known better.

I won't be doing it again that's for sure!

[Martin Harris - Moderator]

Looking again at the original video, it does look like the stall was entered from the prop hang and it never regained controlled flight. There is always the temptation to think that because the nose is pointing at the ground, it must be capable of recovery with a good thumbful of elevator, where this can just result in deepening the stalled condition.

I would be very tempted to add some downthrust, which I feel would stabilise the model in forward powered flight. Without a rudder (?) some right thrust might make the model a little nicer to fly at high power settings too.

[john stones 1 - Moderator]

Yep with the down thrust, having looked again at video, sticks at neutral it looks to be diving vertical (nose heavy), then a handful of elevator gets applied and the fun begins, too much elevator there or too much being applied ? Calm it down, apply minor tweaks till sorted, and if ever there's doubt about your radio, don't fly till resolved.

[ken anderson.]

bonzo,i reckon that the fact that you had the wind to contend with your very light model and ended up downwind....that you wouldn't have much of a chance to get back to where you wanted it...and as you ended up further away and disorientated...that would be the end of any control over the flight as such...hope you do find it...

ken anderson...find bonzo's model dept.

[Bonzo Moon]

Posted by ken anderson. on 30/01/2021 14:00:25:

bonzo,i reckon that the fact that you had the wind to contend with your very light model and ended up downwind....that you wouldn't have much of a chance to get back to where you wanted it...and as you ended up further away and disorientated...that would be the end of any control over the flight as such...hope you do find it...

 

ken anderson...find bonzo's model dept.

 

 

Thanks Ken et al,

A lot of good explanations there guys, thanks. I've looked at the video loads of times to try and figure what was going wrong and I've had tests where things have flown badly but I've away managed to get control and fly back or land. I'd given the model red stripes underside and it was easy to see initially which way up it was. Problem was it didn't appear to be responding to my inputs when I tried to fly back towards me. Plus, although wind wasn't really strong at ground level the higher it got the stronger it was and the faster it disappeared off downwind. I've been an looked a good few times, I can see clearly on the video that it didn't go beyond the tree line but the area below has such big deep patches of brambles it probably dived in and is impossible to see.

As has been pointed out, it was a very light model. The designer said he waited till it was calm late evening before testing. I didn't really pick up on that! My silly mistake.

Plus after that first day test I should have reduced the throws A LOT!  It had loads of expo but you can see in the first test that it was very twitchy and responsive to inputs.

Might build another? I've got more foamboard at home, another motor and servos, but need another RX and ESC!

Edited By Bonzo Moon on 30/01/2021 14:39:11

[Martin Harris - Moderator]

I've noticed that when I'm flying extensively in high alpha flight i.e. stalled but with prop wash providing both lift and control, there's sometimes a moment where I need to consciously switch my brain to "normal aerodynamics" mode on backing off the throttle.

In your case, especially when you may have throttled back to regain control from the prop hang situation where you lost the model, it's perfectly possible that the lack of response to control inputs is because the wing isn't yet working and the control surfaces can't influence its behaviour. Compound this with anxiety about visibility and the loss of control could easily be explained. The lack of any visible response to the controls then becomes less likely to be radio related.

Edited By Martin Harris - Moderator on 30/01/2021 14:46:45

[Bonzo Moon]

Yes, no doubt true. Every time it dived I tried to fly it back with just a little throttle, and I think I had the orientation OK, but it just did it's own thing! It did appear that the throttle was doing it's own thing too, hence the crazy climbing. Anxiety does come into it too though, and eventually I knew I'd reached a point (and said it) where it was gone! Lessons learned.

I was quite pleased with that even model even if it was just a cheap build foamie. I'd put a lot of thought into the build too. Only a couple of days. I guess at least it wasn't something I'd spent weeks building in the traditional way in balsa with lovely covering etc. That would have been really gutting. I've seen videos from a guy on YouTube who builds beautiful jet airliners, and one of his crashed and burned in it's maiden.

[fly boy3]

I am so pleased that Bonzo,s thread has changed it course to the normal freindly chatter that has made this forum such a happy one for me over many years. Comments have been made in an un freindly way at th e start of the thread. No doubt Covid, lock down, bad weather etc has played its part, and no doubt the comments would not have been said in the same way if circumstances were normal. I am on a few other non modelling forums, but ours has always been the most friendly. Well done lads. Take care.

[john stones 1 - Moderator]

Posted by fly boy3 on 30/01/2021 23:15:04:

I am so pleased that Bonzo,s thread has changed it course to the normal freindly chatter that has made this forum such a happy one for me over many years. Comments have been made in an un freindly way at th e start of the thread. No doubt Covid, lock down, bad weather etc has played its part, and no doubt the comments would not have been said in the same way if circumstances were normal. I am on a few other non modelling forums, but ours has always been the most friendly. Well done lads. Take care.

[Paul C.]

Difficult times for everyone and can cause a great deal of stress, good to see nearly all forum posts are our usual friendly banter it's a credit to the folks who are posting 👍. We went to the Çanary Islands early December to visit friends the ĺockdown cancelled our return flights 😨 now our next available flight home is end of March 😱. Nice place of the world to be stuck ! But it's not home and we are far away from our jabs ! . Not complaining it was a risk we decided to take at the time so it's just a matter of getting your head in the right place and waiting for a flight back home. There are many folks in a heck of a worse position than us so we will just make the most of the situation until we can get back 👍

Paul.