Electric Sea Fury

[Danny Fenton]

Hi Shaun glad its going well. Initially we used a 4" spinner from Hobby City. I know others sell them as well. I have the one I fitted initially (sprayed Grey) you are welcome to have it. The alloy one would add a great deal of weight to the front as you rightly say you need to keep an eye on the c of g. When mine was on 8 cells A123 it balanced with a 5 cell nimh Rx pack in the fus at about the leading edge of the wing. When I went to 6S2P configuration the Rx pack had to move back to just behind the c of g. Hope this helps?

 

Don't let Chris scare you, gentle on the throttle and it behaves impecably. Once there is air under the wings on takeoff, increase the speed gradually before climbing. Sudden application of power will make your life interesting.

 

As for flaps, I have mine set to give 45 and 90 degrees of flap on a three position switch, its a beast at 90 degrees but slows nicely on 45 degrees. To keep the tail down fly it onto the deck with some trailing throttle. this keeps a nice propwash over the elevator and stops it tipping over.

 

We are on the 350kv motor, and a 17 x10 or 18 x 10 gives nice trade off between performance and power. IMO If you are using a higher Kv then come down in prop diameter, but keep the same pitch.

 

Send me  a text on my mobile if your bits arrive tomorrow, but I will put a motor, ESC, BEC and spinner in the car in case we have to meet up.

 

Cheers

Danny

[winchweight]

Thanks guys. Still got a long way to go before next weekend.

 

C'mon postie!

[winchweight]

Wahoo! All arrived today!

 

Just get No1 child moved then into the workshop tonight.

 

Heavy motor isn't it?

[Chris Bott - Moderator]

Excellent! All excited now

 

The weight of the motor and batteries just meant that we could shorten the nose to a more scale length. Rather than have to mount the motor on some sort of extension.

 

Didn't you say you had a slightly lower kv motor than our 350? (this thread is so big no it's hard to go back an look)

If it is slightly lower, then I'd still go for the 18x10 over the 17x10. Having said that I'm using a 17x10 on the 350 whereas Danny uses the 18x10. 

 

Danny has ordered himself some spare props and I asked him to get me an 18x10 spare too, so there will be one or two extra at the fly in just in case.

 

As for flying it, I didn't mean to frighten anyone lol, you will probably be much better sticking to your own style than listening to anything we say.

 

Any photos yet??

 

 

 

[Danny Fenton]

Shaun has gone for the 320 Kv motor so might even get away with a 19 x 10 now we are getting into nice sized props, all-be-it a bit pricey to nose over and break.

 

I have a 320 Kv it will be good to see how it performs on the six cell setup.

 

Yes we need pictures Shaun.

 

If Stephen is looking in, any news on whether you will be able to make it next weekend?

 

Timbo did you buy Scotts Sea Fury? a very good price by the way.......

[winchweight]

Nose over and break?????? Moi? Hope not. Have you added spacers to the rear edge of the retract units?

 

No pics as yet as I am building it at work and so don't usually have the camera.

 

Might get some tonight when I work on it though. Just in from removal duties.

 

I intend to fit the motor, esc and batteries tonight as I can't do soldering at work. Lower surfaces all painted in Azure Blue (yeuch!), so after a weekends drying it will be masked up for cammo on top. Brush painting so expect a less than perfect finish, but needs must.

 

Might get the cowl cut tomorrow after Weston (60mm?).

 

How was it BTW?

[winchweight]

Oh and finally, not sure what wire to use. I don't have any silicon wire, so looking at my selection I have Automotive wire in 8 amp, 17 amp and 27 amp wire reels.

 

I am hoping that 8A will do as it's way more flexible than the rest, but I guess not?

 

What does 12AWG equate to?

[Chris Bott - Moderator]

Shaun I'm not sure which wire will do. Obviously the bigger the better. You could be pulling 50A through it, but they are extremely short runs so the ratings are not at all helpful. 

 

This gives some numbers. Probably for solid copper conductors. There is a HUGE difference between the current rating and the fusing current.

 

Is it possible to get the 27A wire in? 

[Danny Fenton]

Hi Shaun, sorry for the brief text messages this morning, I was driving and had to wait until I was stopped at lights and junctions so hence the one word replies. Chris is far better than me technically, so if he says the wire you have shown is okay then I would trust him. but I would advocate getting some 12 AWG at Weston tomorrow. (I assume you mean wire to carry the main current and not charging leads? Charging current is only 10 - 20A depending on what your charger can supply) As Chris says we were drawing 51A static on a 18 x 10 prop from the pack.

 

Weston was the same as always I guess. I am coming to the conclusion that I like fun flys more than the big shows, if it wasn't for the trade presence I doubt I would go. I waited until there was a wail of a jet turbine, that always signals the emptying of the trade tents, especially SLEC, so I could dive in and re-stock my dwindling balsa stock. I was looking for a Ripmax 109 to take along next week, but nobody had one.

 

Cheers

Danny

Edited By Danny Fenton on 19/06/2010 19:45:46

[Tim Mackey]

Hi Guys a slight snag has arisen and thats the size. seagul clam this thing is 66" span and almost 60 inch long - in which case it wont fit in my car

Scott reckons its not actually that big, but before I can part with my cash, I need to actually try it physically, so will do so at the fly -in. Unless Scott flies it there, its unlikely therefore that I will have it ready....although he reckons it only needs a receiver fitting, so maybe I could do that in the evening and fly next day.

[Danny Fenton]

Hi Timbo thats a blow, but great that it is going to someone we know and will appreciate it. I would offer to go and measure mine but the length is dependant on how much cowl is removed. Chris and I took a fair bit off, not sure what Scott did with his cowl. I am sure fitting the Rx at Greenacres is doable.

 

The Fury as you will know has quite short wings in proportion to the rest of the airframe so does appear bigger than the span indicates.

 

But if you need mine measuring just shout?

 

Cheers

Danny

[Tim Mackey]

Thanks Danny...but I think its probably best to leave it until I actually can try to wiggle and squeeze it in the actual car - you will see the problem I have when I get there!

I am hopeful that she will fit somehow - so in view of that, I shall bring less models to the fly-in....in case we end up taking her home with us

I was all set to go up tocarlisle and get it in the next day or so, and get her ready for the fly-in - and intend fitting the ex Camel sound system in her too. I am worried now about the retracts though....I did read somewhere that once you get into double pound figures on AUW the legs get very wobbly ( bit like me own )

[Danny Fenton]

Okay will do. The legs are indeed a little on the wobbly side........ Mine after beer are also pretty unstable. The units themselves seem okay its the piano wire legs that are bendy. The trouble is if you fitted oleos or even just more rigid piano wire then the problem may transfer to the U/C mounts. I know I would prefer the legs to flex than the mounts

 

The sound system may just push this too far, unless you forego some of the duration......

 

I am really looking forward to seeing it. A row of four of these (5 if Stephen makes it) is going to be really cool.

 

Cheers

Danny

 

PS Timbo you really must get a bigger car

[winchweight]

Hi chaps, busy night.

 

The motor, esc and batteries are all fitted. I made up Y leads using the 27A wire. The wire is copper strand and is about 3.5mm diameter. It is thicker than the wire supplied on the esc and motor. The Y leads join the batteries up before the ESC.

 

I have made a safety plug up similar to yours, but I fitted mine at the top of the cowl so I can see it at a glance if it is fitted. I will probably have to use a wire hook to remove it though as it will be almost flush with the cowl. I used gold plugs mounted in a hardwood block. One is nice and tight the other isn't... The holes are the same sizes and so are the plugs. These things are sent to try us.

 

Can't run it up tonight as I don't have a suitable prop. But will tomorrow evening after Weston.

 

Final thing - did you add washers to the rear edge of your retract units to rake them forward a little more?

 

Buy it Timbo..... you know you want to....

[Danny Fenton]

Good progress Shaun well done mate.

 

As to the washers, nope we left the legs dangling as they are. Not had a problem with nose overs well no more than you expect with a warbird

 

Cheers

Danny

[winchweight]

Thanks mate. Cowl tomorrow and run up.

 

Will look out for premade Y leads as I am always unsure about my soldering efforts. Never had an issue yet but never sure, hence seperate rx battery.

 

Paint and final assemby mid week, stencils friday night.

 

Decals next weekend (saturday) and test flying.

 

Sunday RCME Fly In!!

 

Future mods will include scale detailing, exhausts etc, air retracts probably.

[Chris Bott - Moderator]

Sounds like it's really coming on Shaun, nice one.

 

Bring it over even if it's blowing a gale on Sunday. If we're not flying we'll need a boost, and some pics of multiple Furys might just do that.

 

With a bit of luck the weather will be fine and we can have a ball flying them all together, including Timbo's  

 

See you soon

Chris 

[Tim Mackey]

Shaun...sounds like you are making good progress - that lot you did last night would take me a week ! have no fear I do hope to buy it, and the only reason I wouldnt is if it simply wont fit in my car. I didnt buy this car for aeromodelling purposes, and dont intend changing it - frankly I couldnt stomach the depreciation figures if I did !

[winchweight]

Prop, spinner and UBEC bought today. Blimey 18x10 props are expensive.

More work tonight to get the cowl cut and fettled.

[Danny Fenton]

excellent, what did you think of weston? I think you got the better weather than I did yesterday

 

 

[winchweight]

Weather was epic. The show was good as always but nothing really caught my eye. The best display was the full size display by the glider, Pawnee and the Twister. The glider was rolling whilst on the towline and the Twister was rolling around the outside of them!

 

Seemed a lot fewer people than usual though, possibly put off by the entry ticket price. £9.50 each is a lot to pay if you're taking a family. No trade bargains either, quite a lot of r/c "toys" rather than serious models.

 

Anyway, the motor has been run with the 18x10 on it. Turns well and generates quite  bit of thrust, but I am surprised there wasn't a lot more oomph. I haven't run it on the Wattmeter yet as I had other pressing jobs to do. I am marking the cowl for cutting, removing 45mm as the starting point.

 

I bought a plastic 3.5" spinner, going for shape over scale size. I hope it will do the job.

 

Question 1: the prop adaptor suplied with the motor has a sort of thrust washer loose in the bag. It has a hole which is too big for the prop shaft, but too small for the collet thingy to fit inside. I have left it out for now. How did you configure your prop adaptor?

 

Question 2: when I engaged the safety interlink to bring the batteries on line, there as a hell of a crack and spark. Will this damage anything?

 

Question 3: do you seperate the packs from each other to charge them or just do it a one big 12 cell pack?

Edited By Shaun Chant on 20/06/2010 19:47:56

[Chris Bott - Moderator]

Q2 Yes the capacitors at the input of the ESC do take a quick inrush charge which causes the crack / spark.  Some people go to the lengths of charging this through a resistor (i.e. slower) before finally connecting direct. I just put up with the crack, it doesn't damage anything except yr nerves.

 

Q3 The packs can be charged as a single entity in parallel at 20A. Once in a while they need a balance charge (especially when new) and unless you parallel all the ballance connections, then the only way to balance is by balance charging each pack separately.

 

Q1 - just having a think about that one. The prop adapter bolts to the front of the motor with 4 set screws. The collet (like a wheel retaining collet) goes on the back of the shaft with the washer in front of it. This helps with stopping the shaft pulling through the motor I believe. Although I'm not sure it's really needed.

 

I think the thrust may seem a little down because its a large amount (diameter) of air moving slowly, rather than a when we use a small prop where the small diameter of air has to move pretty fast to give the same thrust.

 

Sounds like you could nearly test fly now?? I guess work gets in the way..  Does for me too

 

 

[winchweight]

Test fly???? Noooooo the wings are still in three bits until the painting is over. Would be a short flight!

 

When I soldered up I didn't factor in a charging point, so for now it will have to be cowl off for charging.

 

Q1 - In the back??? That can't be right. The shaft is retained by a circlip. The the big washer has a textured surface which I assume is to go next to the prop? I am very confused. Suffices to say it didn't fly off during the test (which was done in the garden, way from the house, pointing towards open fields).

[Danny Fenton]

Posted by Shaun Chant on 20/06/2010 19:44:20:

Question 1: the prop adaptor suplied with the motor has a sort of thrust washer loose in the bag. It has a hole which is too big for the prop shaft, but too small for the collet thingy to fit inside. I have left it out for now. How did you configure your prop adaptor?

 

Question 2: when I engaged the safety interlink to bring the batteries on line, there as a hell of a crack and spark. Will this damage anything?

 

Question 3: do you seperate the packs from each other to charge them or just do it a one big 12 cell pack?

Edited By Shaun Chant on 20/06/2010 19:47:56

 Hi Shaun,

Question 1, not sure what you mean byt this. there is a small collet which is supposed to go araound the shaft of the motor to stop it pulling forwards. Probably naughty but I rarely fit them.

 

Question 2, Thats only a small crack and spark Shaun.... you try it with 12 cells instead of 6. Then you really do get a crack and spark. If it makes you nervous you can wire a short lead with a resistor in it that you connect first, this slowly charges the capacitors in the ESC (still in under a second) but elimiates the spark and surge when you connect the main leads.

 

Question 3, I charge them as one big 6 cell pack. Though I would do a balance charge on each pack the first time just to make sure no cells are duff.

 

As far as the prop goes, you will not seem to be getting much power, you have gone for the sort of set up that prop calc often says wont work. But if you measure the rpm you will be turning around 6000 rpm on a 10" pitch prop. It will be fine. We like big, slow, props, moving a big mass of air fairly quite slowly. The norm with electric is to go for similar revs to IC and we don't like that. Too inneficient and too noisy, especially if you have on board sound systems.

 

If you are old school like me, (which I am sure you are) close your eyes, imagine the scream of an OS 2 stroke, hold the tail and feel the pull. Is it enough????

[Danny Fenton]

Chris beat me to it lolol

 

There is something you will have to do with the prop washer. (That serrated washer we were assuming was the thrust collet.) You need to glue sandpaper to the back of that washer. As you tighten the prop nut the washer will grip the prop and stop it spinning. As you cannot get to the motor body to keep it still, its the only way to fit and remove the prop. You will find out the first time you try and fit a prop with the cowl in place  

 

I am really pleased to see that Chris's response was almost identical to mine

 

Cheers

Danny