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Acro Wot build advice

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Neil Collett27/04/2018 20:51:50
25 forum posts
55 photos

HI All,

I'm having difficulty deciding which Electric motor I should buy, I spoken to the guys at 4-maxx and they recommended the PO-5055-595 but at £61 plus postage its expensive compared to the Turnigy G60 500KV, which at £43 including postage seems good value, although a number of reviews have commented on the magnets coming loose.

Does anyone have any good recommendations or should I be spending the extra at 4-maxx.

Wasn't sure if I can add links to the websites here, so thought best to leave them out.


Andy Blackburn27/04/2018 21:03:11
448 forum posts
483 photos
1 articles


£43 on a motor that loses it's magnets doesn't sound like very good value to me... smiley

So personally, I'd take a deep breath and spend the extra at 4-maxx.


Edited By Andy Blackburn on 27/04/2018 21:03:47

Chris Walby28/04/2018 06:52:51
672 forum posts
124 photos

You pay your money and take your chance, there will always be people say buy cheap and have never had an issue. Personally I prefer being able to discuss with George details around the set up, what they recommend and buy from them.

This does not stop me buying from other companies for "low investment" models, I just think its very poor form to spend time talking to someone who is running a business and then buy from somewhere else.

Neil Collett28/04/2018 08:12:39
25 forum posts
55 photos

Hi Chris,

Yes I do agree that if a company helps with setup, to go and buy from elsewhere is pretty low. I've already bought most my gear from 4-Maxx, but I was made redundant a couple of months ago (hopefully will be back in work soon), and need to save where possible. I've just purchased the motor from 4-MAXX, so looking forward to that arriving, as need to see where it's going to mount, so I know how much room I have to cut away for the battery to slide in.


Edited By Neil Collett on 28/04/2018 08:16:43

Jonathan M28/04/2018 08:22:06
489 forum posts
257 photos

Go with the 4-Max motor. The cost difference as a proportion of the whole model and all its installed gubbins (let alone the time you'll have invested in making it!) is frankly nominal.

Not sure I entirely agree with Chris' point, however. I understand the sentiment and loyalty to a known, local one-man-band business, but in market terms it is up to the retailer to present their wares and convince the buyer that their product is the right one for them, and this will frequently involve spending time talking to prospective customers. If the motor was completely identical but cheaper elsewhere, then it would simply be competitive market forces that would lose 4-Max the sale - but this isn't the case here as the alternative is of different manufacture and (apparently) of poorer quality.

As it happened I chatted to George at 4-Max just yesterday re a motor for another model. In my case, I am entertaining the possibility of fitting an electric power-train to recently purchased kit and intended by me for IC, and needed to ask some basic technical questions about the power/duration of his listed recommended setup for this model. If I decide to stick with my original plan and fit IC (probably) then my enquiry would turn out to have been a "waste" of George's time, but at least I'll have made it from the point of view of having been fully informed.

PS - Neil, just seen that our posts crossed.

Edited By Jonathan M on 28/04/2018 08:28:53

Neil Collett09/05/2018 08:01:55
25 forum posts
55 photos

Ok, so haven't had much time to do more on the Acro, but a quick update.

All hinging now completed, just need to bevel the edges.

Quick test fit


No servo tray included in the kit, so had to make one up. Also Battery box is starting to come together, and front hatch now cut for battery access.  I doubled up in the firewall which should hopefully be strong enough.


Hopefully can get more done now.

Edited By Neil Collett on 09/05/2018 08:03:51

Neil Collett14/05/2018 14:12:03
25 forum posts
55 photos

Ok got some more done.

Installed the Sullivan snakes, really like these so far. I have stuck on the bottom panel already.


OK so starting the sanding of the top parts.




img_20180514_135739.jpgThank goodness for Perma grit tools, made the job easy.

Tailplane all ready to be covered with edges beveled. But next need to start cutting the canopy, not really looking forward to this.

Also got to start thinking of colour scheme.


Percy Verance14/05/2018 16:07:39
7071 forum posts
141 photos

+1 for Perma Grit. How on earth did we manage before?

Redex14/05/2018 17:43:31
144 forum posts

Hi Neil,

Maidened my Acrowot kit build last week, had 3 flights so far and seems to go really well.

I am using the 4-Max PO-5055-595 motor with a 14*7 prop and an 80A ESC and a 5S 4000 30C LiPo with plenty of room for upgrade to 6S if required. I decided to go with a top hatch entry for LiPo, which is held in place with Velcro straps. Great build log by the way.

David Razor Plane and sandpaper does the job too.

Neil Collett15/05/2018 06:02:22
25 forum posts
55 photos

Hey Redex,

Would love to see a photo of how you did the top hatch, also of your build if you're up for posting a couple of photos..

I have pretty much the exact same power train setup as you, do you know how many amps you are drawing using that prop?


Edited By Neil Collett on 15/05/2018 06:02:40

Nigel R15/05/2018 09:34:23
1854 forum posts
357 photos

Neil, looking good. I like the Sullivan snakes too, they certainly make life easy. People do say that snakes cause trim changes with temperature, but I haven't noticed much of a problem with these ones.

Redex, what flight times do you get from that setup?

Bruce Collinson15/05/2018 11:52:15
160 forum posts


Wish I'd seen your build blog sooner as I maidened my ARTF Acrowot last Saturday. It has the same setup as George recommended except it uses 5A 4S LiPos (same as my Wot 4) and an ESC at 60A. George has specced and supplied three power trains for me in the last year and I rate him.

Yours ought to be quicker on 5S; mine was very cool all 3 flights, cooler than the Wot 4. Unfortunately the battery hatch came off and the replacement has been heavily modified to prevent repetition. One of my clubmates finished one recently and left the cowl cutout slightly narrow so it overlaps the front edge of the hatch and I wished I'd seen it sooner.

Not sure how much similarity there is between kit and ARTF hatches etc but hope this helps; mine's tail heavy (I dislike plastic clevises) and the cart bolts look weedy, too small to risk nylon and the blind nuts are hidden behind a bulkhead.

I'll look out for updates.


Redex15/05/2018 15:27:38
144 forum posts

Neil/Nigel some further info.

The AUW of my Acrowot is 2770 gms, a bit heavy perhaps but my skills are more of 'belt and braces' rather than a 'lightly engineered' model. I fly from a grass strip so have also fitted 3.5inch wheels.

With a newish 5S4000 30C liPo charge to 20.99v on my wattmeter and after a full power static test ,my wattmeter records 19.27v, 61.5A and 1194.9watts. Also tried out of interest a 4S4000 30C and it records 42.5A , 663 watts with the same 14*7 prop.

My TX timer is set to 5 mins for spirited flying and LiPo shows appx 30-35% left so with a bit of conservative throttle management probably get to around 7 mins with a little bit of spare - just depends upon how you like to fly.. Hope this helps.

Neil Collett27/05/2018 12:24:42
25 forum posts
55 photos

Hey all,

So a little more done on the Acro.

First making up the filler for the gap between the fuse and wing, I'm using Microballoons and Finishing resin:


Mix up some resin and then add Microballoons until its like peanut butter:


Really easy to apply, light and very easy to sand:

I initially tried using cling film, but found this introduced too many crinkles into the resin, so did again with wax, although no photo of that, but he's the cling film one:


Next onto some covering - the area is cleaned/prepped and vacuumed to within an inch of its life:


First all white on the bottom:


I wanted a very simple design and I am using Monokote Metallic red and Jet white, have to say first time I've used Monokote and very impressed with it so far. First I make a template using Wax paper and pin strip:


Folded the wax paper in half along the centre line and copied the pin strip on the back:


Then I used the other part of the template to ensure the lines match up and cut the Red Monokote, I used Black 3mm pin striping to make everything very clean:


Unfortunately I completely forgot to round the leading edges, so I may be taking off the covering and re-doing. I know its not going to make any difference to the flight characteristics, but I will definitely notice it.

Next onto the wing - I did the edges first in red as this will copy the same design as the tailplane and then covered the bottom all in which:


Then same again with creating a template for the top. really happy with how its come out:


Test fit to see how's it starting to come together:


right I'm off to go and fly something as the weather is looking alright if a little windy..Cheers All

Edited By Neil Collett on 27/05/2018 12:27:09

Neil Collett09/06/2018 19:33:34
25 forum posts
55 photos

Hi All,

So last update on the build - thank you all for all the help, has been really appreciated. Last few photos of the build:

Wings completed - really pleased with how the servo seating came out:


Fuse all covered:


Battery box completed:


Cover - it has 2 3mm carbon rods to secure at the top and I have added a canopy lock on the front to stop it coming out mid flight.


Sorry missed a few steps, but here she is done, just need to add some stickers. Hopefully maiden tomorrow.




Cheers again all. smiley

cymaz09/06/2018 21:33:00
7916 forum posts
1032 photos

Striking colour scheme....stunningyes

Nigel R11/06/2018 09:39:13
1854 forum posts
357 photos

Nice job!

The Foss designs are popular for good reason - enjoy the maiden yes

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