Mannyroad

Its a plane with great prescence howling through the sky. How did it go with that set up?

Thanks Alan. Repairs are in progress and hopefully (if my mate pulls his finger out and gets on with repairing the tank) I should be back on the road in a few weeks. Sorting this out has stopped me finding some time to get the planes aloft; hopefully that will get back on track soon too. The motor is an S&S 84" performance motor. Rare as hen's teeth.

This is my build project before it slid down the road. Sorry, its blocking the shot of the Mirus, behind.

Heeeey Tony, a nice stable of machines you have there. That trident takes me back. mine had same tank colours, best colours IMO.

Wow Martin, that looks pretty cool. Is that the model in the free plan the other month (or is it this month)? Retracts are a nice touch. How does it fly?

Mark, I will i'm sure, but gently gently at first methinks, hee hee. Tony, had one of those Tridents back in 79. A Hyde conversion. Nice. Love the Trident. Not flown my Mirus yet as I'm busy sorting out damage to my custom bobber (Indian Larry Grease Monkey replica), after dumping it down the road on a left hander last month (on a test run after taking over two years to build it!!). But I'll get both of them flown within the next two weeks and will update this thread with how it goes.

Hi Tony, Thanks for your comments, much appreciated. I wasn't aware about optimum prop sizing to achieve 70% kv; I always assumed one chose a prop that allowed the motor to achieve 100% kv rpm or thereabouts, so the info is useful. Thanks. Out of interest why 70%? I would have thought this suggests the prop is oversize and likely to over-draw on amps. not so clearly. I've read some guys with the same motor are running 11 x 6 props and bigger so maybe my 10 x 6 will rev too quickly. Might need to source a 10 x 7 or 8 to 'push' the motor. But yeas, will check it out with my watt meter and tacho and see what I get.

Might have a go tomorrow, as tides don't cover the beach at the moment.

Just finished my electric version Mirus build. hard to keep hold of the fuselage at half throttle. reckon it will go pretty quick. Wing fits the IC fuselage in the background. not flown either yet. last photo is a pic of my Mirus 'squadron'. The older plane is 8 years old now, needs a recover.

Hi Alan, Just weighed it. It has come out at 2000g (4lb 6oz) dead, 400g more. The battery adds a lot of weight. Don't know enough about electric flight to know what capacity I can get away with for a 6-8 minute flight, especially given that you can only use 80% battery. The 5s 5000mah lipo is not far off 1.5lb!! Some of the changes I made to the electric version added weight too, like adding 3mm ply for the fus bottom, with some small spruce strip around the battery hatch for strength during landings, given most of the bit that scrapes along the floor is hatch. Also there is a sizeable 3mm ply battery tray to carry the battery on bumpy landings, it being a brick. Still, I was very surprised at the thrust it seems to generate, so it'll move fast enough to carry that extra weight; just wonder how fast its going to come in on landing. gulp.

Hi Guys, Well, been busy sorting out bikes and cars and stuff but eventually managed to find a bit of time to have a go at the electric version of the Mirus. I'm quite pleased with how it has come out, though i found myself making a number of changes to get it all sorted. Below is the finished plane, alongside the fuselage of the IC Mirus I built in the blog. The wing is transferrable between fuselages, which might be good as it allows me to swap over to IC whilst the batteries for the electric version recharge. Well, thats the theory at least. Also put in a pic of my full squadron of mirus' too. I managed to get a couple of vents up front by the 'firewall' which means i'll get some good cooling air right alongside the motor body, hopefully. was intending not to have these as i thought they might look a bit naff sticking out of the side, but I thought the motor might get a bit warm, batting along on full chat. I was going to use one of those vented spinners but, from what I've read, evidence would suggest they have marginal if any real cooling ability. so vents it was. Stuck a tail vent in to allow the air out. Will let you know how it performs after testing. Just need to check the CG now, before testing.  I calculated the battery position, offsetting for the loss of the IC engine, tank, throttle servo & RX battery, against the substitute gear (elctric motor, esc & battery).  The calcs placed the battery pretty much central to the desired CG so that will be beneficial should I opt for alternative battery makes, with different weights, as the battery is the chief factor in the calc, being 620g!! If anyone wants any photos showing the main changes made, let me know and i'll post up pics. I was working from a revised version of the IC plan but found I still needed to tweek that here and there; will now update my plan to reflect the changes. Setup as installed is the HK SK3 4240 740kv motor (which if I recall will give me 870watts on a 5s lipo), 60 amp HK Plush esc, 5s 5000mah Lipo. I'll see how it performs with a 10x6 APC-E prop up front (haven't put the watt meter on it yet to see what it draws static). Will say this though, I don't fly much electric, being an IC man, but boy when I nudged the stick to half throttle the plane nearly pulled my arm off! Am well impressed so far; reckon it'll be quick, though having the 5s 5000 battery is causing a weight gain I'd rather not have. One thing I'd like to ask you electric buffs: I've read a few articles/threads on lipo discharging in flight and it seems I shouldn't discharge below 80% of battery capacity, i.e 4000mah. Is this correct? I've always believed that the esc's low voltage cut-off prevented over discharging, hence it cutting power to the motor before battery over-discharge. Is this not correct? If it is, them why do I need to worry if the esc will handle this aspect for me? As I say, I've not dabbled much into electric, the Cartoon Cutlass and my Gonzales being the only two electrics I've flown. help on this welcomed please. Edited By Mannyroad on 18/05/2017 14:36:33 Edited By Mannyroad on 18/05/2017 14:46:47 Edited By Mannyroad on 18/05/2017 15:00:22