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Weighty Matters

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TJ Alexander14/12/2017 15:56:13
103 forum posts

I was reading through the requirements for the BMFA A Test, and I saw that the minimum weight of aircraft was 1kg.

Curious, I checked the weight of my trainer (Champ S+). Flying weight 105g!

Perhaps I should get another nine, and tape them together? And it's not just the Champ - many other trainers, including various Cubs, Mini Apprentice etc are underweight.

It does seem a bit of a strangely high weight requirement, with so many people wanting to fly electric (I'm guessing IC & fuel up the weight a bit).

I'm going to end up having to buy a new plane to take the test, or else borrow one. Not keen...

What would you suggest that won't break the bank (and, no, get into IC is not an option I wish to pursue)? I need a 1kg+ model that's fun & easy to fly, and will talk to a Spektrum DX6, but won't bankrupt me.

Ikura14/12/2017 16:11:12
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216 forum posts

I don't think you can use a model with a stabiliser in it for the BMFA A test.

If it has to be foam then a Multiplex Fun Cub is a brilliant flying machine. There is also the E-Flite Timber (without the stabiliser RX), or a Durafly Tundra. They all fly well but the Fun Cub is the nicest to fly and is probably the best bash about model of its type.

Have fun choosing.

Martin Dance 114/12/2017 16:20:54
169 forum posts
33 photos

An alternative to a new and heavier model might well be to look at the achievement scheme Basic Proficiency Certificate (BPC) designed for the situation you are describing. The test is the same as the 'A; test but allows for sub 1Kg models, you'll find details on the BMFA Achievement Scheme website. The only downside is your club's attitude to it with regard to flying unsupervised.

TJ Alexander14/12/2017 16:26:45
103 forum posts

I believe all stabilising systems can be switched off on the Champ, but that's academic, I suppose now.

I'll have a look at your suggested models. I certainly wouldn't mind a STOL plane, as it is of more sustained interest than a regular high winger.

ETA: Nice models, but they aren't cheap. I'm in the middle of changing job and moving house, so don't have much to spare. I shall have to keep an eye out for cheapish second hand ones.

TJ Alexander14/12/2017 16:28:36
103 forum posts

Yeah, I considered that, Martin. But I'd still need to get the A before progressing. And, as you say, clubs may have their own views...

Martin Harris14/12/2017 18:12:15
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7912 forum posts
203 photos

The problem here is not so much with the A test requirements but more with a club that won't allow someone who only flies very lightweight models to use the BPC as a demonstration of competence.

Some years ago, I "designed" what we called the "L" (lightweight) test for just this sort of situation at our club which was virtually identical to the BPC when people started turning up with very small models. These small models are very different to operate to a 3 or 4 kg sports model which is typically operated by a fairly inexperienced A certificate holder as they progress. If anything, my own opinion is that the "A" test weight limit is too low and doesn't allow a candidate to demonstrate the energy management required for the larger sub 7kg models which many clubs see as appropriate for "A" certificate holders.

If by "progressing" you mean taking the B test and beyond, you will need to make the upgrade to a larger model anyway - and any model capable of the B test will be perfectly suitable for the A.

Edited By Martin Harris on 14/12/2017 18:15:21

TJ Alexander14/12/2017 21:25:13
103 forum posts

That's a very good point, Martin. I shall ask my local club how they feel about the BPC, and not worry about larger models until I fancy going on to another level (when I should be able to take the A without extra tuition anyway).

Could solve a lot of problems.

Frank Skilbeck14/12/2017 21:46:29
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4150 forum posts
98 photos

Check with the club, they may have a club trainer they could let you use to practise and use for you A certificate. As others say above you may find it a little different to fly from a light weight foamie

Denis Watkins14/12/2017 21:57:41
3119 forum posts
144 photos

Best advice yet from Frank

And be patient, as said previously, weight moves along quite differently, but you have your stick experience

So move along at your own pace, and fly your own flight, sounds daft, but fly smoothly your own way

We try to impress when learning, but relax and gain confidence with something heavier.

Surprisingly, heavier craft behave better in the breeze, and you will soon get it

Geoff Sleath14/12/2017 22:00:40
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2914 forum posts
241 photos

Actually 1 kg is a very light model as well - 105 grams is less than 4 ozs! I'd regard that as almost an indoor flying only - or at least fly in zero wind outside. I've just built an SE5a for indoor flying that weighs 45 grams (35cm ws) and is very fragile - it flies with a 1S 200mAH LiPo (I hope! It's not flown yet).

Geoff

TJ Alexander15/12/2017 19:23:33
103 forum posts

I went to my LHS, and asked them what they suggest. They had Wot 4,Riot, and, their top choice, the FMS SuperEZ.

I was quite taken with the SuperEZ, and watched a couple of videos. Then I googled the full spec, and found it was 890g! So close! :'(

Don Fry15/12/2017 20:04:15
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2768 forum posts
33 photos

TJ, at 890g, enjoy. And I bet, that if the examiner is really picky, and has a balance, a preprepared 111 g weight screwed onto the floor at the centre of gravity position would not make much difference. Do a few practice flights first.

And Geoff is right, I have been flying a kilo weight model a lot lately. And it's not easy for me, it has little inertia, it slows up in a moment when up elevator is applied. Mind open the throttle, it moves you out of trouble.

TJ Alexander15/12/2017 21:39:44
103 forum posts

Thanks Don

I guess you're right. Any examiner being that pernickerty would find plenty more to criticise besides!

Seems like I have a plan in reserve if the club aren't happy with a BPC.

john stones 115/12/2017 21:46:10
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9972 forum posts
1472 photos

Best not give his name if you find an Examiner with scales that are out, he'll get hung drawn n quartered. wink

McG 696915/12/2017 21:53:39
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2342 forum posts
974 photos

... isn't that really painful, John?

... even for an Examiner... angel

Cheers

Chris

john stones 115/12/2017 21:57:21
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9972 forum posts
1472 photos
Posted by McG 6969 on 15/12/2017 21:53:39:

... isn't that really painful, John?

... even for an Examiner... angel

Cheers

Chris

Don't know Chris, I've not been caught yet. face 1

Biggles' Elder Brother - Moderator15/12/2017 22:07:26
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Moderator
15748 forum posts
1460 photos

Hi,

the reason for the 1Kg limit is basically that you should be able to demonstrate your ability to safely control and manage an aircraft with a significant inertia, and more importantly discernable energy. Models with higher energies fly differently and require of you a little more flexibility and forethought as a pilot - it isn't going to stop on a sixpence!

I agree with the comment above that basically says 1Kg is not unreasonably high. To be honest on a Saturday afternoon at my club with maybe 20 flyers present, each with say 2-3 models each, I doubt there are more than one or two models in total weighing less than 1Kg! The average would be nearer 3-5Kg I would guess. Now you might say "but I only intend to fly very light models" - with respect, I don't believe you can predict that. We all have had experiences of saying "Oh I'd never be interested in flying this or that!" - only to find a year later we are doing exactly that!! By the way, as someone who has done a fair few IC to electric conversions my experience is that, for like size models and similar flight endurances, there is very little to choose on weight between IC and electric - they are more or less the same.

Final point, can I ask that you don't potentially embarrass the examiner by turning up for the test with a model you know to be unsuitable - ie below the weight limit. Examiners do a hard job and give freely of the their time, we should not seek to make their job more difficult in my opinion. Enforcing the rules, they are not being "picky" - they are just seeking to apply those rules fairly and equal-handedly to everyone. If they let 890g "go", then why not 800g, or 700g, and so on? I think we should all try to respect their position. Just my view.

BEB

PS BTW, In case you think so, I'm not an examiner - but I am an instructor as I prefer to be a "poacher" than a "game keeper" wink 2

TJ Alexander15/12/2017 23:31:49
103 forum posts

All very fair points.

onetenor16/12/2017 00:37:56
1809 forum posts

As a returnee I won one and bought one.Foamies that is. The idea being that I get used to the sticks again then bring my old stuff out of retirement to take the "A" and "B" certificates. Is this a good way to go or should I just go for the heavier jobs to start with?

Frank Skilbeck16/12/2017 08:21:10
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4150 forum posts
98 photos
Posted by TJ Alexander on 15/12/2017 19:23:33:

I went to my LHS, and asked them what they suggest. They had Wot 4,Riot, and, their top choice, the FMS SuperEZ.

I was quite taken with the SuperEZ, and watched a couple of videos. Then I googled the full spec, and found it was 890g! So close! :'(

As others have said Multiplex Fun Cub, it weighs 1130g, so pretty perfect.

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