EPP Foam Kit of a Avro Vulcan B2

[Mark Kettle 1]

Thanks for your comments Ian. For the April meeting Ian give it your best shot, good luck.

[Mark Kettle 1]

I like the battery you put in your Vulcan Tim.

Edited By Mark Kettle 1 on 31/03/2015 10:25:55

[Peter Garsden]

Tim - how does that "patch lead" work exactly - never heard of charging a lipo through a balance lead. I have watched your very good video on making up leads for servos and now do that myself with the recommended parts, but have you done one on this system - would be interested to hear more?

[Tim Mackey]

Hi Pete. I did a thread on this method a few years back but darned if I can find it now - it showed the harness being used on my jart - just seems to have disappeared. I'll take another pic now and try to explain - hang on

[Tim Mackey]

You will need:

A main battery lead connector to suit your charger / parallel balance board socket.

A 2s male balance plug

A 2s female balance socket

Some connection cable (I just used some from the scrap box as charge current is only a couple of amps max )

The lead is made as follows:

Solder the main plug to one end of the cables, and then using thinner gauge wires connect the three pins of the balance plug and socket to each other - be careful to follow polarity and orientation.

On every lipo the outer pins of balance plug are internally connected to the batteries main positive and negative terminals. Looking at the balance plug from above ( barbs on top ) the right hand pin is battery main negative, the extreme l/h pin is battery positive. We solder the pos and neg leads of the main fly lead ( we made that first remember ) onto the wires connected to those pins.

This allows the charger to be fooled into thinking the battery main terminals are connected to it - in fact they are - but we are just tapping onto those terminals via our patch lead. Sleeve everything in heatshrink and jobs a good un.

All that is required is to plug the one end of the harness into chargers main port ( or as in my case the parallel charge board ) and the male balance plug in the balance socket. The trailing cable with the female balance socket is then connected to the lipo balance plug and voila! Balance charging is then operational.

Remember though to limit current to about 2 amp max as we are effectively chrging thro the low gauge balance wires. Pics next

[Tim Mackey]

[Tim Mackey]

[Tim Mackey]

[Peter Garsden]

Thanks for that tim.

Another question - what is the advantage of using a lipo instead of a normal NiMh battery?

[Peter Garsden]

Aren't you using 7.4v instead of 4.8 - my servos I thought wouldn't cope with more volts? Or do they cope and respond quicker with more volts? I have only heard of 6 volts, but also heard of receivers burning out and servos toowith the higher volts?

Also isn't the battery bigger and more difficult to fit in say a mouldie?

[Mark Kettle 1]

I'd like to know these great details

[Tim Mackey]

Well first off there's nowt wrong with vapex / eneloop type LSD cells but I just prefer lithium. I have used lipo packs for about 15 years and have become very accustomed to them. I always struggled with charging nickel correctly false peaking having caught me out more than once in the past. Power to weight is better on lipos, they dont care what soc they are at, and modern cells can be charged v quickly. Im just comfy with the simple operation of lipo
Regarding voltage - there is a small sw mode regulator in the setup shown which drops the lipo output to a constant 5v ( often called a ubec )
The massive choice of pack size and shape available these days means theres normally a lipo available for almost every model.

[Focae]

I use LiFe batteries in my transmitter and the reasons that I do are valid for receivers too.

LiFe batteries don't self discharge as quickly as NiMh batteries so I don't have to charge my Tx battery as often. They are cheaper, last longer and give much better performance. Compared to LiPo, they are nowhere near as volatile, can be left fully charged and can be accidentally discharged further without damage. I use a three cell LiFe in my JR Tx and the voltage is perfect without having to worry about dropping the voltage like you do with LiPo. LiFe batteries are cheap and come in all shapes and sizes. You do need a LiFe compatible charger but most LiPo chargers have LiFe selections these days. The biggest reason to use LiFe over NiMh....reliability.

[Frank Skilbeck]

I recently changed over one of my gliders from a 5 cell AAA Nimh pack to a 2s LiFe, I did this when I changed out the 35 mhz rx to a 2.4 telemetry Rx and found that the Rx volts were sagging significantly as the servos were moved (4 servo wing). A 2S LiFe went in easily (it's a very compact glider) and the Rx supply is now a lot more consistent.

I'm sure the glider also responds a lot more crisply now, but that is probably all psychological

[Alan Jarvis]

This thread shows how to build the kit Avro Vulcan and now it has been hijacked as a battery thread.

[Tim Mackey]

Hijacked? Thats a bit strong as I merely posted a reply to a question from a builder who is following the thread and then subsequently from the designer himself
Technically you are correct however I had requested admin to move the posts to a different thread some days ago via pm - unfortunately it was not actioned quickly enough and if moved now would mess up this thread.

[Alan Jarvis]

Sorry TIm, Yes it was not appropriate.

Here is my finished Vulcan. First attempt at foam and brown paper so I hope to do better next time.

[Mark Kettle 1]

Looking good Alan. When will you be flying it?

The most important thing now Alan is balance C o G and the elevon movements. Good flying control comes from these being set up good.

The tool ( drawing on photograph paper ) is supplied in the kit to aid the setting up of elevon movement.

First set the elevon's level, with your transmitter trims at neutral and with the use of the clevis's on the control rods have the elevon's inline / level with the piece of trailing edge next to the outer nacelle.

Below -Level set

Place the tool over the end nacelle, them mark and draw on the thickness of your elevon trailing edge both sides with a line, that's the two lines you see either side of the dotted line in the top above picture. Then measure the prescribed - 6 - 7.5 - 10 & 12.5 mm lines out from these two edge lines. These numbers represent the pure elevator & aileron movements and the edge of the control surface deflects to these lines for both high and low rates. You will be using elevon mixing from your transmitter so make sure the sticks are giving that pure movement and your not letting any other control creeping in from your stick movements.

Below - Elevator and in this case Elevon moving to 6 mm

Tim Mackey who has a Epp foam Vulcan also sets some exponential, I'll get him to come on this section of the thread for his input.

Alan by the way I like the idea the French had our Vulcan's. it.

 

 

Edited By Mark Kettle 1 on 06/04/2015 19:15:51

[Phil Cooke]

Like the little throw check tool Mark, genius!!

[Mark Kettle 1]

Cheers Phil.

[Alan Jarvis]

Mark

Alan by the way I like the idea the French had our Vulcan's. it.

Well spotted on the roundals just some I had lying about in the drawer.

I wondered what that card was for!

 

Edited By Alan Jarvis on 06/04/2015 20:33:17

[Tim Mackey]

Hi Alan - great job you have done there mate!
Follow the throws as marked out on the little template and you will be fine. I dialled in some expo but of course this is a personal preference. I use expo on all my models and dont bother with rates any more
If you want to try some then start with 45% on aileron and 35% on elevator.
Good luck with the maiden - do let us know how you get on

[Tim Mackey]

Duplicate post 

Edited By Tim Mackey on 06/04/2015 22:07:18

[Mark Kettle 1]

Thanks Tim for your settings on the expo.

For those that don't know the use of Exponential let me explain. Expo for short is a setting in your transmitter which alters the travel of your servo versus the travel of your transmitter gimbal stick. This can give less travel of your controls surfaces around the middle of the stick movements called  - Positive -.  

This setting can help smooth out your flying by giving you finer control however if you need full movement of the control surface this will still be given when the gimbal stick moved to the edge of it's full movement.

Negative expo is the complete opposite giving more servo travel for less stick movements.

 

 

Edited By Mark Kettle 1 on 07/04/2015 00:26:26

[Ian Jones]

Posted by Mark Kettle 1 on 07/04/2015 00:05:42:

Thanks Tim for your settings on the expo.

For those that don't know the use of Exponential let me explain. Expo for short is a setting in your transmitter which alters the travel of your servo versus the travel of your transmitter gimbal stick. This can give less travel of your controls surfaces around the middle of the stick movements called - Positive -.

This setting can help smooth out your flying by giving you finer control however if you need full movement of the control surface this will still be given when the gimbal stick moved to the edge of it's full movement.

Negative expo is the complete opposite giving more servo travel for less stick movements.

Edited By Mark Kettle 1 on 07/04/2015 00:26:26

Depending on the make of your transmitter! Check the effect you get with yours.

Historically negative expo reduces the amount of throw at the mid point because it exponentialy reduces the travel at the centre. So the many of the older makes, Futaba & Hitec for example tend to use that. The newer makes such as Spektrum work in reverse so be careful.

Ian