Phoenix Rainbow EP

[Tony H]

Hi everyone.

 

I wonder if any Rainbow owners can help me? I've been trying to figure out if I can use my 1410Kv 3536/06 (320w) Airtek Brushless motor and if so what would the best prop size be? the recomend for the motor a 9x5.5 or a 10x5 which are both a little small for what the box says (12x4.7 recomended)

 

I find brushless ratings very confusing and often different depending on the website. The kit says to use a AXI 2814/10 (1640Kv) http://www.modelmotors.cz/index.php?page=61&product=2814&serie=10&line=GOLD

 

but when I look at the recomended props the motor spins (2S lipo 9.5X5, 10x7 & 3sLipo 8X4) and the watts on these setups are around the 200 mark seems under powered to me.

 

On the flip side Als hobbies recommends a DualSky Brushless Motor 450watt 1020Kv (XM4240CA-10) which seems way over powered.

 

SMC Recommend 270w+ Brushless and a couple of other shops recomend the Logic 3535/06 which seems similar to mine in spec.

 

I will be running 3s lipos 2200mah and hopefully when I eventually get them from Hobby King 3s 4400mah using my 50amp Arrowwind ESC.

 

Please can anyone with experience let me know what they think

 

Thanks

 

Tony

[Eck]

I'd go for a lower Kv variant of the 3536, Tony. Probably the 1000Kv version, which would be happy on a12x6, or the 1100 Kv version, which I use turning 10x7 3-blade props on my Black Horse B-25 and Seagull EP Edge 540. This would be safe enough on an 11x6, and give about 300W.

 

Hope this helps,

 

 Eck

[Tony H]

Thanks Eck,

 

Ideally I would too but I wondered if I could get away with the motor I already have? running a 10X5 prop 3536/06 1410Kv (310-320W) will probably run at about 10800rpm instead of say 9000rpm at a guess. I orginally bought this motor for a light weight low wing sports plane. I'm hoping not to draw more than around 28-29amps at full throttle. unfortunately I can't test it at the moment as my watt meter is in the post.

 

What do you think, can you fore see any problems?

 

Tony

 

Can anyone shed any light on why the manufacturer would recomend the AXI 2814/10 looks unsuitable to me and it's 1640Kv?

[Pete B]

I use an XYH 3542 1000Kv with a 3S 2200 Li-Po, 40A ESC with a 12 x 6 prop, Produces 310W at 33A, which is enough for good sports performance. Other modellers have used a bigger motor and used the Rainbow for glider towing - vids on the Net.

 

Although it is a light model for its size (mine is 3lb 1oz)  I wouldn't feel comfortable using your proposed setup. The temptation is to use a bigger prop and that will push the amps well up towards the motor limit.

 

You could get the XYH motor from the Cod  for less than £13 - for peace of mind and some grunt at the front end it might be worth considering.

 

Regarding the battery, I had to Dremel out part of the bulkhead to move the 2200mah further back. I've tried it with a 3000mah and the C of G was too far forward for comfort, so you would have to excavate quite a bit to get a 4400mah pack in there. I've settled for flights of about 10 mins.

 

I can't understand why that motor has been suggested, by the way - it seeems a long way from ideal

I'm a great fan of this model, so good luck with it!

 

Pete

[Tony H]

Thanks Peter,

 

I wasn't planning to change the motor but as the one you sugest is so cheap and you have a good experience with it I may go for this setup.

 

Tony

[Barrie Dav 2]

Pete B what make is your 12 x 6 prop for the Rainbow please.

[Pete B]

It's an APC 'E', Barrie. I prefer the Master Airscrews for looks but I've found the APC's can be more efficient - strange how similar specs produce different results.

 

Pete

[Barrie Dav 2]

Thank you Peter.  Although I normally build from plans, I've ordered a Rainbow and am hoping that it's all that it's cracked up to be.  By the way did your Rainbow come with a spinner?  If not what size do you use?

[Terry Walters]

Hi all,

 

I've got a Phoenix Rainbow sitting in a box upstairs which I am plucking up courage to put together so I am interested in this discussion.  Luckliy Pete B only lives an hour up the road from me (in France that's like next door) and so I am hoping to have my own 'Phoenix Consultant' (Ok Pete?).

 

I got to rummage through my motors to see what I have  and whether I need to invest more of the childrens inheritance (what's left of it!) in imported goods!

 

Saw Pete's fly a few weeks ago and loved it and had to buy one - very happy with the build quality.  Pete also put me in touch with various threads on the phoenix including a couple of fuselage reinforcement alterations that are well worth doing.

 

It looks almost to good to risk flying it!

 

TW

[Terry Walters]

Anyone got views on what servos? 

[Tony H]

Hi Terry, I'm going to be using SuperTec Mini servos the have 3.4kg torque (4.8v) and fit the Rainbow perfectly giving it an overall weight reduction of about 51g.

 

Pete, I didn't think it would be possible to get 10min flights with a 3s 2200 lipo, do you glide alot? does it draw quite alot less amps in flight? how much is left in the battery after a 10min flight on 2200? I'm only looking to fly for about the same time?

Could you give me a run down of Watts to Amps on the different props you have tried (if any others)

 

Barrie Dav2, I don't recall seeing a spinner in the box I recieved yesterday.

 

Tony 

[Pete B]

Yes, Tony, I do a fair bit of stooging around at low throttle - I often put my keyfob cam on it to see who's doing what around the hamlet!  I usually put about 1600-1900 mah back in. Having said that, I've been caught out a couple of times stretching it too much and I've landed out without problems. I have a soft cut set on the ESC  so I get a bit of warning.

 

For a more spirited flight perhaps 7 mins would be more prudent. If you can get a larger pack in that would be better but it would need a fair amount of material removing from the lower part of F2. The wing loading will bear the extra weight OK.

 

I've found a scrap of paper from setting up the Rainbow - I've impressed myself there with my housekeeping - with the following data:

APC E    12 x 6      311.8W       32.97A

 

BRC       12 x 6      320.3W       34.82A

Master   11 x 7      320.8W       35.07A

 

BRC     11 x 5.5     256.2W      26.83A

As you can see, the 11 x 5.5 was significantly lower output than the others so a 10 x 5 would probably be very marginal.

 

I used Hitec standard servos on mine as they had come with my Optic 6 and I didn't have a use for them otherwise at that time. I've got some Super Tec Mini L's elsewhere and they have been very good, so I'd agree with that recommendation.

 

I just have a propnut on mine, Barrie - no spinner included, although a 45mm would be about right. I've also put 4" wheels on without the spats as my strip can be a bit rough.I'm tempted to try them sometime - they do add some character to the model.

 

As mentioned earlier, it's worth beefing up the front and rear of the wing opening to prevent squeezing and also to run a spar from the rear of the wing bay downwards to the next former.

 

Pete 

[Tony H]

Thanks Peter that is very helpfull, I wish the retail websites would show more of that kind of information. looks like the BRC props are quite inefficient to me compared to a APC E.

 

What do you think about this motor XYH35-36 1100Kv (Just thinking of saving a few amps to add some flight time). based on this review on the site (below looks like an 11x8 might work well)

 

http://www.giantcod.co.uk/xyh3536-1100kv-brushless-outrunner-pri-402742.html?reviews_id=2167

 

Tony

 

P.S I take it your not using slow fly props or APC thin electric props?

[Pete B]

Thanks, Tony - that motor seems fine, Tony - plenty of flexibility with prop size there.

 

My props are the APC 'E' thin electric as distinct from the sport props which are quite a bit thicker at the hub and intended for IC engines. The BRC ones referred I to above are probably the ones they now sell as Towerpro nylon.

 

Pete

 

[Barrie Dav 2]

Thanks for your input Pete B and Tony.

 

Barrie

[Tony H]

Pete B,

 

Thanks for all your help, the kit is top quality and all looks good as it is. However how do you mean beef up the wing bay on the fuselage?

 

Tony

[Pete B]

Hi Tony,

 

No thanks needed - I've learned so much from others on this forum that passing on some experience is the least I can do!

 

Here are some pics of the mods:

 

1. 1/4 sq balsa cross brace at the back edge of the windscreen between the two wing formers. (I coloured the cockpit black). Excuse the Gorilla Glue overflow:

 2. Vertical 1/4 sq reinforcement behind the slanted cockpit former, full depth, glued into the corner formed by the slanted former and the fuselage side.:

3.   1/4 sq balsa cross bracing at rear end of cockpit, beneath ply wing bolt retainer:

4.   1/4 sq balsa spars, glued from rear of wing seat, diagonally downwards to the bottom front of the next former:

They are all very basic and straightforward and seem to have coped well with some of my more agricultural arrivals! These mods were done after my ill-fated maiden and have stood the test of time.

 

Hope this helps!

Pete

[Tony H]

Excellent! thanks Pete, it was much simpler than I thought it was going to be. Where do you put the ESC in yours?

 

Tony

Edited By Tony H on 09/01/2011 22:23:11

[Pete B]

Yes, like many ARTF's a bit of judicious wood and glue can significantly increase the sturdiness of the model. Why the makers don't do is beyond me - cost and repeat sales,I suppose......

I cable-tied it under the ply motor mount. Plenty of air circulation from the aperture under the prop.

 

Pete

[Tony H]

Hi Guys,

 

Just thought I'd let you know how I am getting on, I finally purchased a watt meter with throttle control from Giant Cod and I tested my new XYH 3536 -1100KV motor, I'm glad I tested it now here are my results so far.

 

EMP(thin) 11X5.5 - 315W   31amps

 

EMP(thin) 11X7    - 415W   42amps

 

 

I may try a 11x5 see how that works out, I'd expect it to be 295W and around 29amps. I haven't tried the 12X6 I'm worried I may overload the 50amp ESC.

 

Tony

[Tony H]

I have also tested some other sizes too (below), looks like it's almost impossible to get an electric 11x5 Prop, can you us IC Props?

 

Master Airscrew 10X8  - 358W  35Amps

 

Master Airscrew 10X7 -  275W  26Amps

 

EMP (E) 9X6  - 253W  24Amps

[Barrie Dav 2]

PeteB,

I've PM'd you.

[Tom Wright 2]

APC do a11 x 5.5 BRC have them.

[Mark Bennett 4]

I appreciate this is an old thread. I've been lucky enough to acquire a Phoenix Rainbow BNIB. It's designed for electric power but the battery hatch has 4 screws which makes changing batteries a bit of a faff. Therefore, I'm considering installing it with a Saito FA30. Those of you who have flown the Rainbow do you think that a 30 size four stroke will have enough power? Just gentle flying. Also, the manual says to epoxy the wing halves together. I was considering keeping them as separate halves for transport. Any thoughts please? 

[GaryW]

On 07/03/2024 at 10:02, Mark Bennett 4 said:

I appreciate this is an old thread. I've been lucky enough to acquire a Phoenix Rainbow BNIB. It's designed for electric power but the battery hatch has 4 screws which makes changing batteries a bit of a faff. Therefore, I'm considering installing it with a Saito FA30. Those of you who have flown the Rainbow do you think that a 30 size four stroke will have enough power? Just gentle flying. Also, the manual says to epoxy the wing halves together. I was considering keeping them as separate halves for transport. Any thoughts please? 

 

 

Hi Mark.. I've got one of these and in my honesty opinion with the actual weight of the rainbow a nice little 30 four stroke wud pull it a Rainbow nicely,, with the wing thats ut choice when builind it but I wud deffo glue them as stated in the manual... keep us undated how it goes and what you decide to do