MattyB

That is a nice mod; it should help with torsional rigidity too!

My point was that because that additional tip weight is well beyond where the carbon spar ends, it is essentially unsupported by anything other than the foam. For that reason if I were going for ailerons out at the very tip I'd be putting in a few cocktail sticks or carbon strip across the polyhedral breaks to stop it sagging and becoming a flat wing. This will also help prevent any flutter at higher speeds (whilst having additional mass out at the tip doesn't make that any more likely, the twisting forces from the ailerons will, especially at speed). Having said that if you can maintain the polyhedral angles effectively my gut feel is this model will need very minimal aileron movement anyway, so it may not be a major issue. Agree on the drag and moment arms, but you don't see many ailerons on the very outboard sections of wings with appreciable polyhedral because that is known to make them susceptible to dutch roll. It may not be too problematic, but the handling might be a bit funky, especially if you use a lot of aileron in the turn. The good news is on a model as cheap as this it's not much of a risk to find out! I suspect you will only need 1/3 of the down-going movement you have there. You could optimise that linkage by moving the connection inboard at the servo end, moving the servo centre in sub-trim so the arm is pointing well forward, and lengthening the linkage to keep the same neutral point. This will give some mechanical diff and improved resolution and holding power.

@Andy Symons - BMFA, is there any update on when we can expect the guidance to be released to members? I’ve checked my email and the news section of the website, but there hasn’t been anything new since Aug 8th I don’t think. Many thanks.

I have read and re-read the first sentence above , but I still can’t work out what it means, sorry… What led you to change your mind from this being a static model to a flyable one, and is that 3-4kg AUW really correct? It sounds hugely heavy for a Depron model, even at 1.6m span.

With that combo of the wing anhedral, short moment arm, relatively small v-tail and large fuselage side area in front of the CG, then “interesting” may be an understatement…

I like the sound of your depron infills and removeable wing (I have been thinking how to achieve the latter), but I am not sure about those ailerons. They are very small and right on the tip, which might increase the chance of tip stalls and (with the polyhedral) exaggerated dutch roll characteristics. It also puts quite a lot of weight right out at the tip, well beyond a point that the carbon stiffeners are effective (could cause some structural issues), and means it will damp how the model indicates in thermals (probably not an issue worth worrying about). This is why I am thinking of keeping it in a R/E or R/E/F config, which for a model liek this should keep weight down and male it simpler to convert.

Agreed - I do think they make it as complicated as possible to understand and respond to these kind of things, then they can say "you see, there weren't a meaningful number of objections/negative feedback" and just push it on through.

Completely agree!

Even if it ended up 300g, on a 2S and 7x3.5 that gives 53W, which doesn’t sound much but equates to 80W/lb - should be fine for a motor glider I think.

Maybe, but personally I am going to wait until the BMFA provides their guidance before deciding how to respond. Hopefully that will be available early next week to give people plenty of time to do so…

In previous consultations of this type there has generally been the option to respond with “no response” to questions you did not have a strong opinion on. Is that not the case this time?

It’s a white paper and request for comment, so there aren’t any formal proposals. If you read the set of posts I made on page 1 of this thread plus the summary of my concerns about half way down that page you should get the main gist. Having said that, one important point… Part of how the authorities get potentially unpopular policies like this through without too much dissent is by making the docs long winded and needlessly hard to understand so people are put off reading them. If you don’t read all of it that is up to you, but so often the devil is in the details, so it it’s to read them. This particular one isn’t actually that long (~30 pages of actual content) compared to past docs on the topic from UK Gov and the CAA.

Am currently think this motor on a 7x3 or 7x4 on 2S… https://www.4-max.co.uk/ppom-2321.htm

I agree with levy. Also, there was only one pic of the model itself, and that was a very wide shot. Any modeller considering this as a project is going to want to see some more detailed shots of the structure to ascertain how well it is put together and whether it is capable of being finished into a model that flies well. Good luck with your sale. 👍

Yes, I’m not sure sun 250g is possible with the “S” version of this model. Apparently according the RCGroups threads the original FX707 (which I’ve not found is available any more) was lighter, but didn’t have all the prep done for an RC conversion. I’m not too worried though, as I suspect 200g might be a bit too light on most days for this windy isle given the relatively draggy non-DLG aerofoil. For comparison the AUW on the original Radian 2m was just under 900g, I’ve thermalled those in gnat farts… ! @Simon Chaddock , what sort of motor/prop combo are you going for? I think I will target 40-50W on a 12-15g motor and 2S pack, but what prop and kV I’ll need to achieve that I’m yet to work out…

To be fair the mistake you made was easy to do - it took me a while to work out what was going on. The problem is that it is so rare to use a single logical switch as both the source and trigger for the same mixer line, this made it tricky to realise no trigger had been set for the action in question.

@Allan BennettUnfortunately there were a few issues with that last file you uploaded, the most significant of which was that you had no enabling switch on the replace line for CH6 (you were using L03 as the source of the mix, but not the switch to trigger it). The bits missing are highlighted below: You had also only copied a subset of the logical switches in my example file, so the reset of the system on activating throttle cut wouldn't work, and the final logical switch in your setup wasn't used for anything and would never have fired (as it's not possible to move the Thr beyond +100). Anyway, to simplify things I have gone through that file, made all changes needed to get it working (including implementing a sticky throttle cut), and tidied up the Special Functions so they are grouped for ease of use/troubleshooting in the future. Everything else (e.g. all your Inputs and Mixer values etc) are identical to the setup you uploaded, so you should just be able to import this model memory into your TX and everything will work with zero changes. Try it on the sim first though to check it all works for you. Magnatilla MB v4.otx (EDIT - the v3 I uploaded first was the wrong file, apologies. If you downloaded that by accident, please delete it and use v4 above) PS - CH8 on the mixer screen I'm guess was just an experiment and isn't necessary, but just in case I set it to exactly follow how Ch1 behaves with respect to the sticky throttle cut. If it's not needed, just delete both lines from your final setup.

In my demo I used switch C rather than B, sorry. Just change the I6 source to SB on the Inputs screen and all should be well. Yep, tested in Companion - that works fine 👍

If you want to get one yourself, eBay is the place - there are plenty of UK sellers with them at good prices, though the prices do seem to vary quite a bit... This is the seller I used. It's so good I have ordered another one too experiment with - I may decide to extend the wings slightly using the second set, or lam film the other wing and turn it into a speedy(ish) pitcheron sloper. Certainly bargainous for <£20, though £69 on Amazon is a bit steep!!!

Kit details… Nice box art, but the packaging inside is non-existent - they have relied on the intrinsic resilience of EPO to get it to you in the right number of pieces! It definitely reminds me of a shrunken Radian 2m, though obviously without the pronounced curved dihedral. It a has a significantly thinner (but still flat bottomed) wing section than the Radian though; this should offer decent soaring performance with a lightweight powertrain, though it won't be a windy weather model in the form I build it. Wing detail - will need some additional outboard carbon reinforcement, but the main spar seems up to the job. The second spar is inserted from the rear of the fuselage to reinforce that longitudinally. Both fit very well. Tail and wing fairing detail. The rudder will definitely need enlarging if I go for R/E/F setup, but the wing is flat enough you could choose just ailerons and elevator (and at these sizes and a/r rations the absence of a rudder might not make a huge difference to soaring ability). Them's some big balls of steel...! 😉😄 Plenty of room for a small 2S pack and ESC, especially if the ample walls are hollowed out a bit and reinforced with carbon strip and CA as req'd. Fuselage from the nose. The plastic inserts seem well formed and glued in, and the servo pockets look suitable for some 4g Aliexpress specials or similar. Plastic inserts for wing and tail attachment Other than one very minor fault in the rear fuselage which I suspect was done in transit, the quality is just super high for the price - the foam is cleanly moulded, dense and strong without being excessively heavy. It’s a smidgeon behind class leaders Multiplex, but better IMO than EPO gliders from the likes of Horizon Hobby such as the Radian. It’s an absolute steal for <£19 inc p&p!

Multiplex foamies are literally the best in the business - impeccably designed, and essentially impossible to assemble wrongly as a result. They are awesome bits of kit and always fly well, though all that careful design can make them initially appear a bit expensive compared to some other options. Anyway, I wouldn't be too cagey about building it quickly - after all, these are designed to be assembled in a few hours, you have plenty of expertise in that now, and Mpx models are way easier than most PNP/ARTFs. By all means contact the soaring club by phone first, but given you have reached a stage where you can competently fly your power model around most of the time, there is no point in going to the hill first time without a model. I say assemble it, set it up on your radio, take it with you for them to check over, then if conditions are suitable and they are happy with i, it can be test flown by one of them. You might even get a go once it's trimmed out. Happy soaring!

FWIW, whilst I applaud your multiple efforts to get and answer to this oft asked question of "how do we get people to build from kits", you may have to accept that the reason people don't is not because the products on offer aren't right. My view is that the world has changed, and there simply aren't enough people left who are still involved that really want to build in that way, if at all.

Cool - I will be interested to see details of the motor and prop you choose, as I have never really done a motor glider at this kind of size and weight before, and don't know anything about the tiny quad motors that seem to be in vogue for these kind of things. Thread created...

This thread will be for those interested in converting the cheap (~£20 inc p&p) FX707 / FX707S Albatross chuck gliders, which can be sourced from eBay, AliExpress or Banggood. My personal goal is to make a lightweight, cheap "Mini Radian" for the park - let's see how it goes! More details to follow - @Simon Chaddock, feel free to post details of your conversion in this thread too. Useful links: How I originally found out about this model RCGroups conversion thread (pitcheron version) YouTube build and fly conversion series Another useful Youtube vid:

PS - That may be required on an output with a servo (I've not used a Futaba set for ~25 years so wouldn't know), but it shouldn't matter a jot if you are outputting to a sound module. Try changing it to 100% and see, but remember, if for any reason it the response to the SC switch is the wrong way round, reverse it on the Mixer or Servos screen, NOT Inputs (funny things related to trims can start to happen if you do that on primary controls; it's simplest to remember only +ve values should be used at the Inputs layer, then these issues will never happen).