Opinions Futaba BLS257?

[Varelco]

What's the general consensus around this mini tail servo? I'm thinking of getting one with Futaba's 153 cyclics to use on a Logo 480 Xxtreme but I want to get peoples opinion first. Would it be upto the job? Would like genuine reviews on it really, not "fit a 251" as thats not really helpful. If I did get one it would be running on 5.7v so the performance will be better than the figures advertised.

Thanks,
Matt

[bigpops]

Isn't that a mini size servo? A brushless version of the S9257?

I wouldn't have thought it would have anything close to the torque needed on a heli that size.

[Paulice]

the tail servo is a full size so the 251 would fit but are a bugger to get it.

[philipjdall]

Yeah I'd also recommend using a full size... The 153 is a good servo but IIRC it still has plastic gears? Plenty reports of them being quite brittle, you might be better off with the MKS ds9660A+. I have them on two different helis and both are super locked in. Zero slop even after hitting the dirt a few times.

Phil

[mahbouni]

Futaba BLS257 is a great tail servo. I am using it in my Mini Protos 450.

In my Logo XXtreme 480 I am using 3 x BLS153 and a BLS251. One side frame is cut for mini size tail servos, e.g BLS257 and the other side is cut for standard size, e.g. BLS251. The BLS153 cyclic servos were not a perfect fit. The bolt holes aren't the exact distance apart. I used some MSH servo adapters but I had to drill the servo adapters out to give some tolerance. Also I needed to shim the elevator servo to get the linkage rod vertical.

As for plastic gears in the BLS153's , there's nothing wrong with that and they're not going to strip in flight. They will strip if you crash but in my experience so do metal gears. I don't crash often but when I do I usually have to replace servo gears, regardless of whether they're metal or plastic. The advantage of plastic is they don't develop slop so quickly like metal gears do.

[Varelco]

Thanks for the input gents.

Yes the BLS257 is a mini tail servo which Is why Im interested in some feedback on it, never owned a mini on a tail.

I beg to differ about it having insufficient torque. There are popular standard sized tail servos out there with only 1-1.2kg/cm more torque than the BLS257, yet people are quite happy to fit these to a 700 sized heli swinging 105-115mm tail blades. The BLS257 would only have to deal with 72mm blades, not to mention it will be running on 5.7v so this torque figure will be closer to these full sized servos.

The MKS DS9660A+ is a great servo I have them on my Goblin. I do like the idea of the brushless higher spec 153s though. The plastic gears don't bother me, I don't crash often so that isn't a factor in my decision. Although they sound like a complete ball ache to fit which is off putting.

The others I'm considering is JR's ELS01 and ELG01, they look good but apparently are pretty power hungry.

[mark Taylor]

I'm using mks DS 9660A on cyclic and a BLS257 on the tail of my Gaui X4ii

No problem at all

the BLS257 is more than up to the job on the 480 tail IMO

[mahbouni]

I agree that the BLS257 is more than up for the job on the 480. What influenced my choice between it and the BLS251 was getting the CG right. Your choice of battery may not fit under the pinion, which would leave the CG too far forward with a BLS257. The BLS251 adds a little bit of weight to the back of the heli and allows larger packs to be used up front.

[Toolman]

For a mini tail servo consider the New MKS HV9780,
Really nice, & full size servo spec without the weight.


Tim.

[philipjdall]

They will strip if you crash but in my experience so do metal gears.

I've had a few hard crashes with my 9660's and never had a gear strip yet. I'm using the mikado Futaba horns and they didn't break either - perhaps I have just been lucky.

Out of interest how hard is it to change the gears on the 153's?

[mahbouni]

Sometimes when I crashed, the metal gears didn't strip completely but I could feel they were notchy at some point in their travel, so I replaced them anyway.

I can replace 153 gears in about 5 mins but 1 st time you do it will probably take longer.

[Varelco]

I agree that the BLS257 is more than up for the job on the 480. What influenced my choice between it and the BLS251 was getting the CG right. Your choice of battery may not fit under the pinion, which would leave the CG too far forward with a BLS257. The BLS251 adds a little bit of weight to the back of the heli and allows larger packs to be used up front.

I would be using my 30C 4000mah GensAce, which are 42mm x 50.6mm. Could you do me a massive favour and measure the distance between the bottom of the pinion and the battery tray? Unfortunately it looks like my batteries are just a touch too wide to fit on their wider side, Mikados site says the battery slot is 53.5mm tall which means they will slide under the pinion, but Dave Dahl says the battery slot reduces from 60 to 50mm under the pinion. If this is the case my batteries wont fit underneath it. I could do with some confirmation on what the distance is.

If I can get away with using lightweight 26g servos I will go for them I plan to make it as light as I can.

[mahbouni]

Hi there. I couldn't get my calipers into the frame under the pinion without disassembling the heli, so i tried various battery packs for size. The largest pack I could get under the pinion was 58mm tall. Literally it touches the bottom of the motor shaft of my Pyro 600-11, which is 23mm long. The pinion sits about 1mm higher. Also take into account that I have 1 layer of Velcro on the bottom plate, which is probably about 1mm thick. No Velcro on the battery though. So i would say Dave Dahl's measurement of 60mm is about right, assuming no Velcro and the Scorpion motor shaft isn't 1mm proud of the pinion.

[Varelco]

Thanks mahbouni. That's perfect I have plenty of room under there with my packs.