Rebuild of a friends F16 .. which he then gave me !!

[solentlife]

Originally Posted by Bill G

Along those lines, the recent lipos have C ratings high enough to not require large cells sizes, as they had in the past. Weight is so critical on most of my EDFs, that I just live with short flight times and use a relatively small battery that meets the power requirement. With some of them, 4 minutes is plenty of excitement for me anyway. Of course some models require large cells for ballast, but we try to avoid that as much as possible. Most of the newer ARFs I come across spec much larger batteries than I would use on models of their relative sizes.

My findings are that often there is no substitute for cell capacity .... I've tried high C and still ended up with limited power / puffed packs. Nano's are a no-no with me having wasted money on them ...

As above ... the problem here is to find a combo of motor / LiPo that will live more than a minute or so ! I cannot carry 6S as that's too heavy. A 4S is a joke in this model ... so it's 5S ... but a decent KV motor for 5S is hard to find.

Nigel

[Bill G]

Originally Posted by solentlife

My findings are that often there is no substitute for cell capacity .... I've tried high C and still ended up with limited power / puffed packs. Nano's are a no-no with me having wasted money on them ...

As above ... the problem here is to find a combo of motor / LiPo that will live more than a minute or so ! I cannot carry 6S as that's too heavy. A 4S is a joke in this model ... so it's 5S ... but a decent KV motor for 5S is hard to find.

Nigel

None of the high C ratings have ever proven to be realistic from my experience. A simple watt meter is enough to determine that running a CBA is not necessary to dismiss their discharge charts as being completely unrealistic. The notion I was getting at was to sacrifice some flight time for reduced weight. Obviously there is no point to using an undersized lipo that will not hold up.

I have one of these motors in a 70mm EDF for 5s that seems promising.
http://www.hobbypartz.com/96m821-2860-2550kv.html
Of course the vendor is US and out of stock, but maybe they are available elsewhere. Some who have flown the setup on 5s have shown good results. Personally I think the motor/70mm fan are a bit weighty, and would look at it from Jet Plane Flyer's analogy when used in a smaller jet. While not the same performance, I'm convinced that a lighter 64mm high performance EDF motor, fan, and 2200 mAh lipo can provide good performance for a jet at this size. Again a personal preference, as I prefer to hand launch, versus having to haul launching devices to the field, along with everything else. Most of my jets are scratch built, but a good ARF example would be the Starmax HE162 that I had, where I added additional weight with CF reinforcing. RC Castle provided it with a 64mm outrunner/fan, that I'm sure was not the most potent of the lot. While some may laugh at the GWS fan, they can handle considerable power when very well balanced, and are light. The weight difference between 64mm and 70mm fan setups when also considering the required batteries can realistically in the 10oz range, which provides considerable slack for the lower power rating. I think that's the page that JPF and I are on. The plane had good performance (read not slow by any means) with an EVO 3s-1800. I gave it to a friend who had a number of flights on the setup with a 4s 2000 by the time I witnessed a flight, and it was quite fast with that setup. Plenty fast enough that I could not see changing to a larger motor and battery.

[solentlife]

Bill ... I have to admit to finding the 70mm a disappointing set-up... airframe size is good and I like - but the 70mm ... putting it diplomatically - Rubbish.

I have to say that my 64's and even my 50's put out nearly similar figures in thrust when installed. The out of frame figures for 70mm quotes of 1.2kg etc. - yes I can get those easy, but stick into the airframe and BHAM it's like shutting the lid on it. I get 800 - 900gr if lucky.

I don't like marginal power ... and these are just that.

It's why I'm fighting to get 5S in there ... run-time as long as I get 3mins WOT ... I'm fine. What I want is a machine that will PERFORM.

I think I'm spoilt by my 64 and 50's ... they DO perform and well.

The F16 I have glides well ... that's its saving grace. But the Twister is a 'brick' that is down-right awful. After 45 odd years of model flying - I know a brick when I fly one !!

So the hunt goes on ... my 2800 5S capable motor is sitting at home waiting my return from travels .......... who knows it may work ....

Nigel

[solentlife]

Fitted this :

http://www.hobbyking.com/hobbyking/s...ner_630w_.html

With 5S 3000mAh Turnigy 25C pack .... I now have 1.1kg thrust installed. Motor is running warm only ... LiPo is warm to touch only.

I may now have an answer !!

Nigel

[JetPlaneFlyer]

Nigel,

What is the all up weight after the power upgrade, about 1.4kg?

[solentlife]

Originally Posted by JetPlaneFlyer

Nigel,

What is the all up weight after the power upgrade, about 1.4kg?

Yep.

The original with all the bits and bobs ... retracts etc. is supposed to run about that weight. When the guy gave to me - he'd removed the retracts and added GRP work to underside. So once all repairs were completed she sits out at 1430gr.

Thrust is about 1050+gr with the 5S .... so obtaining a 73-75% ratio ... which is not so bad.
With 4S - the weight drops to 1240gr ... with thrust about 900gr .... flyable but to me marginal.

Nigel

[solentlife]

She Flies !! The motor survived the 5S ...

Video ......

Lanxian F16 5S + 2800kv + 70mm

She launches well ... Vilnis and Vladimir previously .. both say she goes of the hand OK for a big model. In the vids she stands on her tail and high alpha's out !! On the sticks you are waiting for opportunity to dip the nose down ... and level her out.

It is a big and heavy model - so speed is always going to be limited. I may see about removing some of the underside covering. Where so much repairs in her life - it was really rough - so I covered all with packing tape and then painted ... That probably accounts for a reasonable weight penalty. Haven't decided yet !

But glad the motor and model is now a positive addition to the hangar !

Nigel

[solentlife]

Not so lucky of the bungee ....... servo arm snagged the front rail and was pulled out of it's slot ... made her bank in to the right.

F16 failed bungee launch

It will be sorted !!

Nigel

[solentlife]

Refitted servo .. modified rail fixing ... waited suitable day.

Hooked up, fired up ... hit the trigger ... initial dip of rails as this is a heavy model for my light bungee system ... away she went and into a smooth flight !!

Wonderful.

Sadly the video cam failed to start and I cannot upload a vid of the occasion ...

Nigel

[solentlife]

Cirava ... ex Soviet Fighter Airfield .....

F16 Cirava 19 May 2013

Nigel