Messages

1

Scale / P47 - Electric Conversion.

« on: June 13, 2014, 16:41:37 PM »

Hi Keith,

Thanks for the feedback.  Yes the washer on the ESC is only temporary, a couple of cable ties will be employed.  Good point re airflow, I'll make some more holes.

Regarding the right thrust, the odd thing is it doesn't look like there is any by default.  The standoffs were machined up on my lathe and are all the same to 1/100mm.  I might need to knock a small bit off two of them if there is no right thrust by default. I'll have to get  the t-square out to check.

Thanks for the idea re the sleeve for the pushrods, sounds like a champion idea.

Hopefully some more progress this weekend.  In fact I don't see why I can't finish it.  I do plan to do a bit of airbrushing.  At some point I might even redo the covering as it's a little bit tatty.  That's another day's work.

Cheers.....
Dave.

2

Scale / First Scratch Build Foamie.

« on: June 12, 2014, 22:11:20 PM »

Here's some pics of my very first scratch build.  A mustang based on free plans from here;
http://www.flyingpenguinrc.com/p51-main.html
It was straighforward enough to build.  I would like to do better on the canopy next time but for now this will do me. All the control surfaces seem to work well including the landing flaps. I put a 1200kv outrunner in it.  For now it has one of those Orange RX with satellite.  I hear bad things about these so I'll replace that at some point.  Haven't tried to fly it yet and wont until I have a proper club membership and can do so at an approved site.  A little big for the park methinks. Only took me a couple of nights and I wont mind too much if I thrash it as long as I learn from the experience.  The decals were interesting.  I found that you can get inket printable vinyl which is adhesive on one side.  However I doesn;t like getting even the slightest bit damp as the ink runs all over the place.  SO what I did was tried it through a laminator.  Turns out that after laminating, the backing paper is unaffected and peels off perfectly, leaving  a lovely shiny decal which is now laminated on the outside and self adhesive on the inside!

3

Scale / P47 - Electric Conversion.

« on: June 12, 2014, 21:51:10 PM »

Hi LK,

Did you see the progress in my post from May 22nd?  I'd be very interested in your opinion on some of the issues I raised in that post.  Been a busy bot in work since then.  Hopefully more progress later in the week.

Cheers...
Dave.

4

Scale / P47 - Electric Conversion.

« on: May 22, 2014, 23:15:40 PM »

Hi Guys,

I've been a busy boy this week installing everything.

First up was the front side electrics and motor mounting.  

..and a close up of the mounting.

I machined the standoffs from 10mm brass bar.  None of this is permanently fixed yet.  I don't have any 4mm anti-vibration nuts, so I need to get some.  What you don't see here is an aluminium plate (1.5mm thick 20grams added weight) at the rear which ensures that the bolts can't tear through the firewall.

I'm a bit concerned by the rudder setup.  I used a pull/pull setup.

, but I'm not happy the way the wire just rubs along the slot in the side of the fuse;


I think some nylon tubing will be used here to prevent the wire rubbing and snagging.

Here's how the rudder and elevator controls terminate at the servos.


Here's the starboard side aileron servo;


BTW I got the servos used 3xS3001 and 2xS3003 for 25quid on e-bay.  They all seem good.
None of these are glued yet so everything can be moved/changed.  Spot anything you wouldn't do or any better idea's for the rudder?

5

Scale / P47 - Electric Conversion.

« on: May 20, 2014, 16:34:14 PM »

I hooked up the electrics over the weekend and yes there is quite a spark but its not as scary I as I thought. Just a flash and pop, certainly nothing that I'd be worried about. However when you look close at the connectors up real close, you can see little pits where the little arcs struck.  I guess given enough time these little pits would add up to degradation of the connector. I will try adding the parallel resistor trick later and see if that stops the sparks.

6

Scale / P47 - Electric Conversion.

« on: May 18, 2014, 00:11:27 AM »

Hey Guys, I found where I saw the resistor thing.

http://youtu.be/CJQoUcm7okc

This makes good sense. Watch the vid, its all explained in there.  The trick is to put the resistor in parallel with the negative terminals and then disconnect the wire with the resistor installed when you're powered up. I have so big 7watt 10ohm resistors so I think I'll give this a go. I just dont like the idea of the sparks. I suppose a simpler trick is to wear a pair of rubber gloves to avoid getting burned but that doesn't stop your connectors getting carbonised.

7

Scale / P47 - Electric Conversion.

« on: May 17, 2014, 00:26:57 AM »

Thanks little Keith :-)

Actually I didn't choose the plane, it was given to me by a friend who started to assemble it and never finished it. But if I were to choose a jug would be well up the list anyway. I just love old warbirds, sure I married one:-) (she better not read this)

Yes I got 2x30C 5Ah 6S's. I was looking at the 8Ah ones but they were nearly double the price of the 5Ah ones. Batteries start to get pricy when you go up that end. I made some more progress this evening. Got all the control surfaces hinged up and the tail section installed.  Next trick to install the control rods and wires. The wire that came with the plane look a little flimsy, a can hear the mid air 'ping' followed by expletives so I'll get stronger rudder wire. I also need to get hold of some T connectors as the batteries came with bullet connectors.

I heard that putting a low value power resistor in series can help avoid sparking on these big lipos. Is it necessary?

Cheers
Dave.

8

Scale / P47 - Electric Conversion.

« on: May 14, 2014, 13:58:18 PM »

Thanks for the welcome Fred.  As my late mum used to say, 'One man's carpenter is some plumbers customer'.  We all have out areas of expertise. I build a lot of the astronomy gear myself so this is a big help with building RC stuff as I have ended up with quite a well equipped workshop and have at least got some experience of engineering.

I went with the Turnigy G60/500.  It is advertised as 500Kv 1500W and is sold as a direct swap for a .60 glow engine.  I sort of figured that the 120W per pound would work here and I have roughly calulated the final weight around 10lb including battery so 1500W will give be a little more to play with and if it proves too much, I can just derate the throttle a bit anyway.

I haven't settled on a prop yet.  I would like to find a suitable 4 blade (for scale).  But props are cheap so its something I can afford to experiment with a bit.

Regards,

Dave.

9

Scale / Ziroli 92" P-47

« on: May 12, 2014, 22:58:47 PM »

Unbelievably Awesome!! Enjoyed every single photo.  You should be incredibly proud of that build.  :clap:  :clap:  :clap:

Dave.

10

Scale / P47 - Electric Conversion.

« on: May 12, 2014, 22:50:21 PM »

Hi I'm Dave and I'm in Raheny.  Delighted to find an Irish RC forum.  I thought I was going to be forever tagging along on the UK sites hoping they don't mind too much.  To be fair, they're nice guys. Might as well start with a bit of an intro.

My primary interest is fixed wing.  I've only being doing this a few months but I've learned loads and broken lots of stuff. No not really, I've been fairly lucky.  I did manage to break my Ultra Micro Spitfire once but a bit of foam safe CA fixed it all up good as new.  I'm not in a club yet but intend to go along and introduce myself to the guys in the Phoenix Park at the next available opportunity.  I just love building stuff and know that I will end up building most of my own stuff as I get a great kick out of that.

My first major project will be to complete and convert a 57" span balsa P47 given to me by a friend a few years ago.  I got it mostly planned out where everything is to go and put in a nice order to hobbyking over the weekend for all the bits.  It's going to run on a .60 equivilent outrunner. Off a 6S lipo and an 85A ESC.

Here it is laid out on the kitchen floor.



There's a whole lot of hardware with it too, some useful some not so useful.  Those brass hinges are nasty.  They stick and just seem to be poor quailty.  I've ordered some CA hinge sheet to replace these.





So the build begins.  I decided to make the battery hatch on the top side of the nose section.  The battery will go behind the firewall. There is plenty of space in there.  



The ESC will probably be on the front of the firewall with the outrunner so it gets plenty of air.  I imaging I will have to make some more holes in the firewall to let air through to keep the lipo cool too.  This is how I envisage it will be, however there is also the option of installing a chute so the lipo will go in diagonally.



Here it is marked out ready for cutting.



...and after cutting.  It seems my balsa warbird is a hybrid foamie!!



I made a dummy battery from ply to test fit.  As you can see it rides a bit high however there is a few inches of foam at the bottom so I plan to make a recess in that just big enough to capture the bottom of the lipo and also so it sits down further.  I will wait right to the end to do this when I have a better idea where the COG will be.



Well all the gear has shipped from hobbyking.  I bought some used Futaba S3001s on ebay.  So more when all that arrives.