Biggles' Elder Brother - Moderator

I've not fitted it to the Flightline Spit, but I have done so to the FMS P51 - that was straight forward and worked well. Clear instructions etc. I do have the 1600mm Flightline Spit and was considering putting a module in that. I haven't looked at this closely and I could be wrong, but my first impressions were that there wasn't a lot of suitable room - a bit of a squeeze. As I say I can't be sure of this but it might be worth checking the dimensions of the unit and making a card cut-out and experimenting with fitting it in. Remember you have to find space for the transducers as well - though that isn't such a problem. You might also want to consider a separate battery for it - and that's even more room and weight. BEB

Hi Bruce, yes I had an electric version WotsWot (until I stuffed it coming out of the reversal! I swear the ground moved up 20 feet!) I liked the "plate" idea and may well use it here - or I might just put in a ramp, a non-slip mat and a big Velcro strip.

Another suggestion for Steve Webb models. Friendly knowledgible staff and very well stocked - if you like building upstairs at the shop is an Aladin's Cave!. BEB PS Just be aware of one thing,...there is a special lock on the door at Webbies which means you can go in no problem, but it seems to be impossible to get out without spending at least £50

Whoa Nigel, I meant no slight to you or anyone. Of course they are your models mate and you're free to do what you want with them! I did more or less say that right at the opening. All I really wanted to do was see if we could have a sensible debate about the current situation (no pun intended!) regarding power levels. I feel there two thing we could think on: 1. I feel, just my opinion, that "standard expectations" for power are creeping up under the influence of us all. So a few years ago 100W/lb was seen as respectable, now some folks are openly saying things like "an average model needs 150W/lb" - and I'm not sure it does! And more,...how long before 180W/lb becomes "the norm" and then 200W/lb and so on. 2. Now you might think "so what? if more power is the norm what difference does that make?" Well I think it's potentially missing a trick - in reality we all know that electric power is balancing act, we are trading: power, weight and endurance. But if we become too wrapped up in one of those three maybe we miss the chance to advance in other areas? So we go all out to squeeze 1.5kW out of the model, but it's duration is 6 mins? If we backed off just a little - maybe to 1.2kW we might get 8 mins from the same set up? All I'm saying is surely this is worth discussing? 1.2kW would still be lots of power for that model - so why not have the power and the endurance. Also, once the verticals are unlimited - can they really be even more "unlimited"!? In short - if you want to to be "ballistic" and enjoy that - that's fine. But we should be careful I think of drifting into making that the normal expectation. As I say, no challenge intended - just an invitation to discuss. But maybe its better on another thread of its own while we ponder Bob's missing amps! BEB PS I have no idea what YMMV means!   Edited By Biggles' Elder Brother - Moderator on 20/09/2018 20:33:09

Firstly this isn't meant as a criticism of anyone, its just a thought this thread triggered and a view that has been forming in my mind for some time - so I'm going to get it off my chest! 6.5lb with 1500W! That's 230W/lb - bonkers territory!! The model may be a 3D model but: a) I don't think, from what I have read, that Bob is looking for that. b) 150-170W/lb is plenty for 3D. Approaching 200W/lb well maybe, but 230 is far too much in my view! I have been thinking about this for a while now. As electric-power flyers we came from the "NiMh, just about enough power to stay airborne for 4 mins" tradition. Now we can have more power we almost seem to have gone power mad!! I actually believe we are overpowering most models now - just because we can. And yes, I'm as guilty as the next man! Today people view 100W/lb as "puny - very low power" The reality is for most aircraft 100W/lb gives a good general all round performance. OK verticals might not be unlimited, but they will be as big as most folks need them to be! !20-150W/lb and again a lot of us are sniffing at that now! But the truth is that's very lively performance. Scale warbird for sure! Danny Fenton I believe is of the view that lower power to weight ratios often lead to much smoother and scale-like flying in scale models. And just to show what might be possible, at the extreme, look at David Mellor's experiments flying on 10W/lb! Perhaps we could save ourselves some money, weight and space (as well as gaining in endurance) if we weren't so uncompromisingly power hungry like we have "something to prove"? BEB Edited By Biggles' Elder Brother - Moderator on 20/09/2018 17:16:56

I have been spending some of this morning fiddling with different battery arrangements and combinations. The two 6s 3000mAh solution won't go, basically I can't get two packs through the hatch and even if I could, while they are each slightly narrower than a 5000mAh they are not much shorter. I thought I'd include a few photos of the battery in context so you can see the issues better. Sorry these are not wonderful quality but they were taken on my phone held and operated in one hand while my other hand held the battery in place! The first picture shows why the battery can't go vertical in the cowl: And the next photo shows that it can't go upright in the fuel tank bay either: Now it could go on a slope - as Bob suggests: So far that looks my best option. Your suggestion is good Nigel, I have done something very similar to that previously - see the photos below. I started with a motor box: Then cut a big hole! And installed a "poke through into the cowl" sloping battery chute: The problem is,...call me lazy,....but it is a lot of extra work for a winter hack! If I end up with the CoG too far back and need too much lead I can revisit this and do it if I have to. But for now I'll hold that in reserve! BEB Edited By Biggles' Elder Brother - Moderator on 20/09/2018 12:50:28

Hi Nigel, its actually for Lithium Ion - but the same basic chemistry applies of course. The source was here - quite an interestng site and one worth a look at if you are interested (as we are!) in batteries, their use and care. BEB

Thanks for all the ideas chaps - brilliant stuff. Bob - yes I did the sloping battery tray trick with my Chipmunk conversion, so that might well help and I'll certainly have a look. As you say the impact on the CoG would be very small, but the convienience, in terms of getting the battery in/out and snuggled down securely, is potentially considerable. Geoff - the fundemental problem is even if I could open the space by re-designing the mount and just about get the battery in betwen the actual firewall and a back plate to the motor it would have to be vertical - I've recently done exactly that on a BlackHorse Sea Fury. But in this case the battery is taller than the depth of the cowl so it wouldn't fit! I never really realised hown much the front of a WOTTY tapers. The bottom of the fuselage comes up quite sharply and that line is continued by the cowl itself and so you end up with a surprisingly small cowl and frontal area for what is a fairly "chunky" model! Shaun - I don't have any higher capacity 3s batteries, but I do have a number of 6s 3000mAh batteries and two of them in parallel to make a 6s 6000mAh might well be a possibility as they may be short enough to go vertical against the firewall - thus reprising Chris's idea above. I could also slightly stagger them in the stack - as I say the floor slopes upward to the front in a taper. I shall look at that as well. Thanks again chaps - all ideas much appreciated. BEB

We did it back in May. There is a model policy document on the BMFA website and we just adapted that. Emails were then sent to all members and that was iit. Pretty straight forward really. BEB

Coming along nicely Devcon!s Really takes me back, I built my first WOT4 from a Chris Foss kit many years ago now. Lovely plane, had a Irvine 53 on board (the classic combination!). Sadly she came to a sticky end one evening in a mid-air collision - the only time that has ever happened to me (touching every bit of wood around him!) BEB

Suggesions are always welcome Chris!! Ideas from members of this forum has saved my bacon on more than one occassion! BEB

It's a good question/suggestion Chris - but sadly my lipo's are just about10-15mm too tall if placed at the front. They might fit further back, but then there would be no advantage over just laying it flat. BEB

I have looked Geoff, believe me I'd like to get the battery up there as well. But the frontal area on the WOTTY is surprisingly small, this means the standoffs are very close together - at motor spider pitch - and there isn't really much opportunity to build a two stage mount with a wider forst stage because of the small area. I think we are stuck with what we have. I don't think the battery will be far enough forward to eliinate all the lead, we may still end up with at least a little.We'll see. One thung about this model is it's built for IC and its an old design, so it's massively over engineered for electric power. The wood in the structure is thick and heavy. More modern IC models are made of CNC cut interlocking ply. This gives them the strength to withstand the vibration of IC without the bulk and weight. Compared to them this aeroplane is rather "agricultural" in design! BEB Edited By Biggles' Elder Brother - Moderator on 19/09/2018 21:15:37 Edited By Biggles' Elder Brother - Moderator on 19/09/2018 21:16:49

So, today was supposed to be "ESC fitting day" - but when I got into the shed I realised that I was just dodging a job here. You see doing the ESC is easy, sorting the battery isn't! "So let's all go and do the ESC?" No, let's be grown up, grasp the nettle, and sort this battery. I can't properly site the ESC, with the right length leads etc., until I know where the battery is going to be anyway! Basically its going in here: The fuel tank bay. I'd love to get it right up in the cowl - but it's just not possible. The cowl is too narrow and there is no space between the standoffs etc. So the fuel bay it has to be. For some reason there is a whopping big thick chunk of hairy balsa there - epoxied in. Oh joy! I don't know why, it only held the old ESC which, although large, wasn't that heavy! I need to get this block out, its taking up space I want to use for something else. Boy it was a job and a half! It was stuck in there never to come out and of course access was tricky. But a combination of a scalpel, stout knife for levering and eventually a pair of long nosed pliers finally won the day! I have it back as it was originally! So, why am I so concerned to lose this block? Well, after much squinting and eyeing up, I think that if I cut a hatch in the top of the black covered fake windscreen I could get a 6s battery in though there! It couldn't be a long hatch, or wide, but it is deep giving us maneuvering space. So battery nose down first and than wiggle it into position. If that works there would be no need to take the wing off to change the battery! So I marked out the position of a hatch on some masking tape over the "windscreen": Took a fresh scalpel blade and a very big breath,..... and started cutting - the moment of commitment. You have to do this very gently I find, using very many light strokes - you don't want to dig in. I was surprised at how thick the top wood was, I had to swap over to a longer scalpel blade at one point. But eventually I got there! And here is the hatch cover,... basically the cut out piece! You can see how thick it is. I now need to trim that a bit - it's a very tight fit! - and fit some pegs and catches to retain it. Does it work? Can I get the battery in? You bet yer!! You could hold a dance in there! So, pleased with that, once we get it fitted probably we can look at battery retention but I don't foresee any big issues there. Phew! Time for a bottle of Spitfire I think and a nice sit down! BEB

Thanks for that info Steve. I do like that arrangement. BEB