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Battery Hatch Query

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Tosh McCaber03/07/2020 16:22:04
124 forum posts
23 photos

1 eyelash- photo.jpg2 eyelash elec components.jpg3 eyelash.jpg
4 eyelash elec conversion.jpg

A photo of my Eyelash, which I'm in the process of converting to electrics. Beautiful little pattern plane- a mini version of the Eyeball, a .70s pattern plane with zero-zero incidence setup. This is my second- they go like stink with a Cox Tee Dee .049! However, not flown for the past 20 years. Wingspan 38", Weight 22oz

The next photo shows work in progress. As well, I've shown the original plan, along with another detail plan showing an overlay of my proposed conversion layout of electric components. I have adjusted the electrical component setup to find CG, moving the battery to suit.

Whilst there's a fairly large volume inside at the front of the fuselage, the battery looks as though it's going to have to be positioned where I'm showing it- pushed back to be partially into the area below the wing. I will build up the floor to provide a flat surface for Velcro to hold the battery in place.

I don't want to have to unscrew the top cockpit cover, and then the wing to change batteries between flights! Looking at where the battery would be positioned, I think that a hatch will have to formed at the bottom of the fuselage access battery removal?

Since I'm a novice re electric set up, I'm looking for any suggestions as to where a hatch to should go, how big, and how it would be fixed, to give access to the battery, for ease of exchanging the batteries. Presumably in front of the battery. But if the battery is held in by Velcro, wouldn't it be difficult to manoeuvre in and out!?

Geoff S03/07/2020 16:55:11
3700 forum posts
29 photos

The battery needs to be as far forward as possible. I'd be surprised if the CoG was in the right place with the battery as far back as shown. If possible push the battery under the motor.

Don't rely on Velcro to secure the battery but but a small amount is useful to stop fore and aft movement. As you say, it can be extremely difficult to extricate batteries if there's a lot of Velcro. So a hatch as big as possible in front of the cockpit and minimal Velcro to stop battery slide with a Velcro strap round the battery that holds it firmly in place.


Tosh McCaber03/07/2020 17:15:23
124 forum posts
23 photos

Hmm, thanks Geoff, but, having used tape, and sticking motor, and associated ESC etc where they're going to be, the position that I've shown the battery is where it all balances out!

That being the case, my original thoughts for a top hatch would leve the battery 'way down and inaccesible!

Bob Cotsford03/07/2020 18:13:07
8637 forum posts
483 photos

Build up a box around the back of the battery and glue a pair of velcro straps to the top and bottom so that they wrap over the front of the battery, or even a rail each side with a front 'door' to the box sliding in from underneath to hold the battery back. For fixing I like a tab or dowel at the front of the hatch and either magnets or a sprung catch at the rear. As the hatch is in the belly then I'd plump for magnets. This was how I set up my mk1 Easystreet, velcro strap and hatch magnets.

If you wanted a top hatch couldn't you slope the battery so that the front was within reach and the rear tucked under the wing LE?

Edited By Bob Cotsford on 03/07/2020 18:14:45

Peter Jenkins03/07/2020 18:22:20
1624 forum posts
305 photos

Don't forget to provide some cooling to the battery and an outlet at the rear of the fuselage to allow the air out.

If it's going to be a tussle to connect the battery while keeping yourself clear of the prop, consider fitting an arming plug on the fuselage side. The type of battery connector you use is handy provided you can engage and disengage the plug without excessive force. That way, you can have vulnerable bits of yourself close to the prop without any danger provided the arming plug is removed first!

Richard Clark 203/07/2020 19:28:19
418 forum posts
Posted by Tosh McCaber on 03/07/2020 17:15:23:

Hmm, thanks Geoff, but, having used tape, and sticking motor, and associated ESC etc where they're going to be, the position that I've shown the battery is where it all balances out!

That being the case, my original thoughts for a top hatch would leve the battery 'way down and inaccesible!

Just put a hatch slightly larger than the battery on the underside of the fuselage. Simples.

I leave it as an exercise for you to figure out how to make a strong yet quick release hatch catch so the hatch retains the battery should it attempt to escape during a high G manoeuvre .

john davidson 103/07/2020 19:41:58
65 forum posts

Having converted several models to electric , the firewall is always too far back and needs to be removed and a new one situated as to keep the prop in the same place and allowing the battery much further forward ,thus avoiding using ballast , a new hatch then can be made at the same time.

kc03/07/2020 19:58:25
6576 forum posts
173 photos

I agree with John - the firewall is usually better moved forward so the Lipo can go where it needs to balance and also give access to connect up.  A top hatch for access whilst connecting/ disconnecting safely out on the field seems very desirable. If the hatch comes near the canopy then you might consider making the canopy part of the hatch.

Edited By kc on 03/07/2020 19:59:44

Tosh McCaber04/07/2020 09:41:06
124 forum posts
23 photos

Thanks for all the replies.

It only requires an 8mm spacer behind the electric motor to arrive at the existing position at the rear of the prop. As I mentioned, I have mocked up motor and ESC positions, and unfortunately, the battery needs to be where I've shown it. To push the battery forward would increase the nose heaviness!

Bob Cotsford04/07/2020 09:48:46
8637 forum posts
483 photos

Battery shelf at 45 degrees sloping down and back keeping the centre of the battery on the same vertical line as you've drawn it, top hatch, peg front, spring clip at the back - job done.

In fact looking at your drawing it looks as though you could even drop it in vertically against F3 keeping it's mass in the same place longitudinally, though comparing the drawing with the photos, are you sure you've drawn the battery actual size?

Edited By Bob Cotsford on 04/07/2020 09:54:26

Tosh McCaber07/07/2020 15:39:50
124 forum posts
23 photos

Thanks foir all the replies- I think that I've cracked it- I'll upload a photo of the end result when I'm done.

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