FMS 750mm Zero - Battery Placement / CG

[ckotula]

Hi-

I've been loving the 800mm Corsair, it turned out to be very nose heavy despite reading all over the forums about people putting weight in the nose to get it to balance. I found it basically flew stock without any modifications and the batter didn't have to be jammed all the way forward.

I just got the mini Zero (v2) and just wanted to check with anyone else who has one to see about cockpit configuration and battery placement.

1) That space is so small I've literally taken 30 minutes to even find a way to get reciever, ESC and battery in there. If I want to cut out some foam, where to do it, as it seems I might cut into the actual pilots cockpit by doing so.

2) I'm finding the plane to be quite nose heavy out of the box, but again am reading people talking about adding nose weight. Currently I have the ESC and the receiver stuck up in the nose, and the battery, a 1000mha 2S, basically center of the cockpit right in front of the servos. This seems to be the only way everything will fit in there and when balancing the plane, it seems spot on. I attached a picture. Just kind of scared for the maiden since everyone talks about shoving the battery way far forward.

Possibly FMS/Motion added nose weight to this model?

Any other tips for a successful maiden of the mini Zero would be appreciated.

[Loneflier]

Re: FMS 750mm Zero - Battery Placement / CG

I have the Zero, and love flying it, but I made a couple of changes to mine. First, I did end up adding some weight to the nose to get the CG where I wanted it. I very possibly have made it nose heavy because it does not float much at all, and comes in for landings pretty hot. I will probably start removing about .25oz at a time and see how it affects the flight. I also switched to a 2 blade prop, an 8x6 to avoid the expense of replacing that nice scale prop every time it came in on our grass field. On mine, I placed the receiver and ESC where it appears that your battery is located, and I push the battery (1300mAH 2 cell Admiral) as far into the nose as I can get it. All of it fits well, but kind of tight and it can take a bit of fiddling with the battery wires to get the canopy to close tightly.
Other than that, I have had no problems with it. It does fly fast, and is very aerobatic. I keep the expo set about 30% and dual rates are set at about 80-85% on low, 100% on high rate, with the same expo all around. Hope this helps. Good luck with it.

Rich

[ckotula]

Re: FMS 750mm Zero - Battery Placement / CG

OK, thanks.

I've tried the battery up front and balanced according to the factory prescribed CG (those red dots on the top of the wing) but the thing is literally rock solid nose heavy in that configuration.

Is yours a V2? I'm just worried that they put a ton of weight in the nose based on feedback.

What to do? Maiden it with what my CG calculates out as with the battery back or go with what it seems 100% of people say with throwing the battery up towards the nose?

I had this same issue with my 800mm Corsair, everyone saying throw it forward and make it nose heavy and ended up having a harrowing maiden with the thing wanting to nose dive until I had exhausted all up elevator trim.

This plane is too pretty to crash and burn on the maiden!

[Loneflier]

Re: FMS 750mm Zero - Battery Placement / CG

Yes, mine is the V2. My CG is about 3/4" in front of those red dots, and like I said, I am a bit nose heavy, but the plane flies fine. I have plenty of throw left in the elevator. The only issue with mine is that it does come in hot for landings. Just for a comparison, I just checked mine, and even without the battery in the plane, I am nose heavy based on where you are wanting to balance your plane.

As for damaging the plane, well, my Zero has had a couple of really bad crashes in the first 2 flights, but with some epoxy, you would be hard pressed to tell it. I believe the crashes were due to not enough right aileron on take off, since it cleared the ground, and promptly rolled left and went nose first into the ground, breaking off the nose. The other crash was due to a bad hand launch. Again, some 5 minute epoxy, and she is as good as new.

The reason I start with nose heavy is from my experience with the FMS 800mm Skyraider. The instructions were off on my plane, a Version 2 as well. It called for a CG at 65mm from the leading edge. I did this and the plane was very tail heavy and not flyable. After doing some research, I discovered most people were using a CG of 40mm. Once I changed the CG to 40mm, the plane instantly became stable and fun to fly. Like most people will tell you, a nose heavy plane may not fly well, but a tail heavy plane only flies once!

[ckotula]

Re: FMS 750mm Zero - Battery Placement / CG

Loneflyer, thanks for your response and checking in on this.

I re-arranged everything and had to cut out some foam to make everything fit. But you are right that with the battery up front and calculating CG a bit forward of those red dots it does balance perfectly. So I'm going to go with that.

Too funny about the torque roll. Literally every time I hand launch my 800mm corsair at 70% throttle, it is a controlled, out of control ,first few seconds as the plan rolls left and is all squirrelly until it gains speed. Feel like I'm come close to crashing it every time on launch but have managed to just pull out, then I enjoy the next 5 minutes of exhilaration.

Do you find right rudder or aileron to be the best course of action, I've always read rudder is the way to counteract this?

Landing is a whole other experience, these things do come in hot unless you have a headwind to flare into.

[Loneflier]

Re: FMS 750mm Zero - Battery Placement / CG

On take off rolls, I use just a touch of right rudder, just enough so that it tracks straight, but I also keep some right aileron dialed in until it gets off the ground and starts to bank right. Then I can give it more throttle and she flies fine. If you watch the videos of Mike and Ryan when they fly these planes, you will notice that they always bank to the right after take off, and if you stop the video and look really close, you can see right aileron applied. That is how I figured out what I was doing wrong and it does seem to work well. I have tried to develop that habit with all my planes now. Unless it is an ultra micro, I really prefer a ROG take off vs. hand launching since I can react to rolls faster.

Good luck with your Zero, they are lots of fun.

[ckotula]

Re: FMS 750mm Zero - Battery Placement / CG

Loneflier-

I've got about 10 flights on my Zero now, glad I took your advice for the battery placement, etc. The thing flies extremely well, tracks straight out on a hand launch at 70% throttle. Loving the plane.

Unfortunately, I don't have a big enough flat place to do RoG takeoffs or landings - I fly in kind of a tidal marsh area with patches of long grass and the occasional bush which I find make great crash landing catchers. This plane is really tough, but it does come in hot.

The exception is the stock 3 bladed prop. I ordered 3 extras and have smashed all of them so far.

I see you mentioned you switched to a 8x6 two blade. I just ordered a handful of these APC ones. But my new question is, how best to mount them?

I've read that a prop adapter really will not work on this plane since the shaft is so long and threaded. Can I just tighten them down with some 3mm hex nuts and washers?

Care to share a picture or advice on how you installed the 2 bladed prop?

[Loneflier]

Re: FMS 750mm Zero - Battery Placement / CG

Hey ckotula,

Glad to hear your Zero is flying well. I flew mine this weekend, and as usual, it does really nice. I totally understand what you mean about the FMS props for these planes, and that is why I went to the 2 blade prop. I used an E-flite 8x6 part number EFLP0860. I also used Dubro 3mm hex nuts to thread onto the shaft. The prop has a hex nut cut out on the back side of the blade. Just get the right amount of clearance from the cowl to the prop, and set the 3mm nut there. I used a flat washer with another 3mm hex nut on the front. Make sure you tighten it well. Then to cover the exposed motor shaft, I used an E-flight micro rubber spinner, part number EFLA204. This looks pretty close to the correct size spinner, maybe a bit smaller, but looks good with the Zero. I left mine black, you could paint it if you wished. I fly on grass, and with just about every landing, the plane will flip after a short landing roll, but so far, I have not had to replace any more props. I admit, it doesn't look as nice as the FMS stock set up, but it works just fine for me! They do come in hot as you noticed, but they fly really nice, even in some wind. Hope this helps! If you need a picture, please let me know, and I'll see what I can do to get one posted. I have not tried that before.

I should have added that the spinner I noted above simply presses onto the shaft and works really well.

Thanks,

Rich