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Old Aug 23, 2002, 09:22 PM
Red Merle ALES
Curtis Suter's Avatar
United States, Mt, Helena
Joined Apr 2002
5,674 Posts
Four*40 Motor/Battery/Prop?

A friend of mine is converting a Four*40 to electric. I've read all the threads I can find here about this but it seems that a lot of folks are looking for vertical performance or even 3D performance.

This is his second airplane and all we're interested in is having normal aerobatics and being able to loop without diving. We'd like 8-10 minute motor runs.

We'd like a brushless setup.

Any recommendations? Any help would be greatly appreciated.

Thanks
Curtis
Montana
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Old Aug 23, 2002, 11:50 PM
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Rutherfordton, North Carolina, United States
Joined Apr 2001
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Here's a nice inexpensive setup that will easily give 10 minute flight times with very good performance when you push the left stick forward.
Ed
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Old Aug 24, 2002, 07:51 AM
AMA 697691
Rochester, NY, USA
Joined Aug 2000
8,110 Posts
Hi Curtis,

You may want to give Pete a call at Model Electronics Corporation (or MEC) to help you decide on a power system. The Turbo 10 with Super Box combination has been recently reduced to $75.

Another higher end system would be a geared Cobalt motor from Astro Flight. The 625G or 640G Cobalt systems are very durable and provide good aerobatics on a 40 size plane for less money than a high end brushless motor.

Good luck!
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Old Aug 24, 2002, 09:21 AM
Visitor from Reality
United States, VA, Arlington
Joined Dec 1996
12,788 Posts
Hi Curtis
I'd suggest a search on the type through these pages. The Four Star is about the most converted glow kit around and have never heard a soul say a bad word about it, regardless of what they did to it.

I've had one for four years nearly. Converted to electric, she was in a review article in EFI (Feb 1999, and on the cover!) I've flown her ever since, with a couple of downspells for repairs and even more 'conversion'. Right now, she's taken on a new lease on life with a MaxCim 13D on 4:1, 16 cells, a 13 x 8 prop and the ability to come off the runway and go vertical until I say stop.

On 14 cells, with the MaxCim and the same prop/gearing, performance is much as you'd expect a glow 4* running a strong 40 or average 46 to have. Having said that, I tend to turnaround aerobatics and the flight times would go way high if flown less intensely - I leave hovering to helos (and Gary Wright ), preferring aircraft that move forwards in usual fashion while flying

MaxCims have the advantage of providing flexibility, with easily swapped gear ratios - you can take a model from mild to wild by swapping a cheap pinion gear on the field with a couple of hex keys. If you call MaxCim, it may take a while to catch up with Tom Cimato, but he is "MaxCim".

Other good options - but beware of 'cheap' power at these sizes - are the rash of Eastern European brushless motors. You're often left to figure out what fits on what, what controller to use and might soon be finding out that Keith Shaw's saying "Buy cheap, buy twice" is actually true.

Better spend a little more, go somewhere where you get good advice (if all else fails, call Kirk Massey at New Creations).

Even more options - calmer 4*40s have done well on Astro 15Gs 25G, with various ratios. Price of these is up past low end brushless motors but I don't recall anyone ever wearing one out. You can sometimes pick them up cheaply from folk who want to buy real sexy BL motors. If they are in good shape, there's years of flying in them, and controllers are still 'cheaper' than BLs.

FWIW - I think the extremes of powering a 4*40 are 8 cells for a super lightweight copy that was all contest balsa and so one, to up around 24 / 25 cells and a big Astro. Mine has flown great on 14, 16, and 20 cells, using MaxCim 13Y and 13D motors, plus an Astro 25G on 16 and 20 cells.

You're probably more confused than ever!

Figure out the budget. Figure out a system that will give you a little more power than needed - so you can power back and cruise with a reserve. Buy the best, most proven system you can. Flexibility is real good - you might want to escalate the 4*s performance later, or move on to something more exciting.

Then comes the woodwork! If there's one thing I do know, it's how to convert the glow kit, mostly using the wood in the box, to a practical electric. It's a bit long of a list though, drop by and chat about that any time. I'm probably going to replace my old gal this winter, so may have some other ideas. The 4*40 is one of those models that can best be replaced by another 4*40!

The model you'd like is so easily achievable, its a wonder the Chinese aren't selling it in a box by now!

Regards

Dereck
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Old Aug 25, 2002, 11:03 PM
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Joined Jan 1999
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Hi Curtis,

I've been flying a converted 4 Star 40 for a few years now on a few different setups (this was a glow ship converted over, with no lightening performed). One way I flew it was with a MaxCim 13Y motor, 3.33:1 gearbox, APC 14x10 E prop, and 21 SR Max 2400 cells. This setup had enough power to go straight vertical, with long flight times if you used the stick reasonably. Later I went to 16 3000 NiMH Panasonic cells in MEC power tubes and a Jeti 45/3 motor geared 1.7:1 with an MEC gearbox. The prop was a 14x10 APC E. This didn't have full vertical, but it did have plenty of power to fly easy aerobatics, and very long (8 - 10 minute) normal flight times. I'm currently flying the plane the same way, but with the 45/3 direct-drive and using a CAM 11x6 folding prop. This too is a very nice setup - very aerobatic, and 8 - 10 minute flight times on the 3000's.

Steve
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