Going Electric - With Electro Flyer!

Mark Takes Out The Hacksaw!!
By Mark Stringer

Just coming into July and what has happened to the weather? Nice and sunny sometimes but when ever I have had the chance the wind has just been too high to get down to the field - just a couple of days this month (not that I get a lot of time anyway).

New Web Address
OK, so what have I been doing this month? Firstly as far as Ratby goes there has been a LOT going on. We are now at www.ratbyaeroplanes.com and have more web space to play with. So there are more pages and every model has its' own page, with more details, so that you know what is what. We have a new e-mail address of sales@ratbyaeroplanes.com as well.

Cell RatOn The Models Front
I have held off on the ARTF Cub and T-Hawks due to problems getting them over here from China with any reliability. I have more than made up for this however with a whole new range of ARTF and ARC (Almost ready to cover) models. Everything from Trainers, Aerobatic models, scale models, gliders and electro models - take a look at the site to find out more, as there is just too much to list here.

Right then - back to business - electric models. Due to weather problems I have not been able to fly the models covered here so you will have to wait until next month for the final outcome.

Firstly, I will cover the development of my "Cell Rat". I decided that it would go like "stink" on 16 cells and it had the wing area to carry the weight. Due to previous pilot error (I am not too proud to admit it!) I was short of a fuselage for my Cell Rat. In case you don't know the model it is a 66" span aerobatic model with fully symmetrical wing section and an all in line make up (engine thrust line, wing centre line and tail plane are all in line). probably not what the average electro flyer out there is flying! - Anyway, I decided to borrow the fuselage from my "Rat Off The Hill", the slope version, so out came the hacksaw and I took the front straight off it. I just needed it to test a theory! Using a standard .60 size engine mount (slightly opened out) I mounted my Sport Twin Team Gear unit on the front.

I then worked out the best positioning in order to get 16 cells in her and keep the C of G sensible. I decided to make a hatch in the top so that I could get to the batteries easily.

I added a platform from lite-ply inside to hold them (two on the tray and one towards the front), this also allowed me to have the speed controller and fuse easily accessible .

Underneath this was room for the radio switch and RX battery pack (held in with double sided tape), the servos and receiver.

This all worked out very nicely and kept the C of G just a little bit forward for more stable flight. I will add some weight to the rear once I am happy with it and I hope to get sparkling aerobatic performance from her with this many cells. I am using a Master Airscrew Electric 13x10 prop which should spin at at least 8000 rpm - I will check this and also report on how she fly's next month - as long as I can get a decent flying day in before then!

Next - The Spitfire.
I have waited long enough to get this one moving forward. After the earlier disappointments I have made the following changes.

I got rid of the speed 400 and gearbox, opened out the inner bulkhead so that I could get a speed 480 in place on the correct thrust line. I then made a new front former that fits to the outside of the original one and held in place with 3 small screws. This also has cooling holes in for the motors, which is mounted on it.

Having had a good look at things after the earlier very short unsuccessful flight I realised that the grain on the front of the battery compartment ran in the wrong direction and had split. This not only let the battery move forward but would mean that the battery cover would fall off if it did so. Not so good in the air when using a BEC!

I added a small ply plate on the inside of the fuselage at the front and screwed two ply catches to it to hold the battery cover in place and replaced the front of the battery compartment with a lite-ply one for strength.
Not all together the best looking idea but at least it is safe and secure and the alternative could have been the need for one of those famous black bags! Again, the proof of the pudding will be when I get the weather for the flight - let you know next month.

The old Butterfly with the Team Gear Mini Single will also be under further tests this month and I will update that next time as well.

And Finally...
Finally this month, and possibly the most exciting, I may have some news next month of new batteries for us electric flyers!

I think that we all know that the biggest set back with electric flight has been the weight of the battery and the principle that the smaller they get the less power they have. So if we could have a 3000mah cell that was is rated at 3.7V giving a charge voltage of 4.2V and measures 5.4mm x 64mm x 95mm and weights just 63g we would only need 2 of these in the average model which would save us about a third of the battery weight in our models. Impossible! - NO! - I have some on their way to me for evaluation - maybe not by next month but certainly by the one after. I just hope they are as good as they sound as they could re-revolutionise electric flight.

I will most definitely report on these as soon as they are with me. (I know there are already a few of these floating about out there but I hope to bring all of you news of this revolution!).

I should also have a Dimwatt, Discus and T-Strike for review over the next month or three. I will do these together, spread over a couple of months.

Have fun and good luck with the weather!

If you have any questions then please get in touch with Mark at:
or check out his web site at: