Dennis' ARTF Acro-Wot

My introduction to the Acro-Wot was around twenty-two years ago, when the club was flying from inside Kirkistown race circuit. Pinned to the wall of our club hut was the lid of the box that the Acrowot came in and I thought it was a great looking plane and still do even twenty seven years after it was first kitted with its white/yellow colour with red and orange trim and having been designed by Chris Foss you were guaranteed a plane that was going to be a joy to fly. I would be surprised if there was a club in the UK that did not have at least one Acro-Wot flown at one time or another, in fact in our club, Pete, Richard, Michael, Patrick, George, Steven and Peter are some of the members who own (or have owned – ouch!) at least one.

 

I can’t really say why I never bought an Acro-Wot kit but the price and having to glue bits of wood together to make a plane never really appealed to me! I have owned a Wot4 along with quite a few other members, which is also made by Chris Foss and is a very versatile plane.  As you will know they go like the clappers with a tuned pipe or can hover in a breeze and the flight characteristics do not change even with floats fitted.  Knowing that the Acro-Wot flies just as well as the Wot4 is the main reason why, for the past three years I have thought that if the Acrowot was made as an ARTF it would be one I would buy.

Last summer it was rumoured that an ARTF version was being launched but it was only this spring that Chris Foss was happy enough with everything for it to go into production. Ian at Icarus Models phoned my order to Ripmax in April but they still could not give a definite delivery date. Sods law would have it that I was on holiday the day it arrived in July.

 

The kit:

The first thing I noticed was how small the box is, measuring only 37inches long but when assembled the plane is 47.25inches (1200mm) long, has a 59.25inch (1,505mm) wingspan and weighs around 2.3kg just perfect for an everyday (or weekly) hack.  The recommended engine is .40 to .55 two stroke (OS55fx shown in the instruction manual) or .56 to .81 four stroke and five servos are required.

 

 

With such a delay getting this plane into production my hopes were high that it was going to be better than average and I was not disappointed. Lots of thought and quality are everywhere, from the way the plane was packaged with tape holding components in place to prevent damage, the extensive (good quality) hardware, covering was well applied with no wrinkles and was a good match for the painted fibreglass cowl.  Quality of wood and construction of the fuselage was good as were the built up wings and solid wood tail plane and fin, even the canopy is trimmed, pre tinted and the painted rear section again a good match with the covering.

 

 

 

The colours and trim used are very much the same as the picture in our club hut all those years ago and although the outline of the plane remains unchanged there have been a few minor changes. Most noticeable is the rudder now comes over the top of the fin to give an increased area also the wing instead of a straight leading edge now “wraps” itself around the fuselage and also the front of the plane is wider than the kit.  So, being more than pleased so far it was a (brief) read through the manual.  I say brief because it has fifteen pages and sixty five photos, in fact I have seen manuals for trainers with less information!

 

 

The purpose of this review is not to tell you what goes were, as this will not be your first model, but to tell and show what is ahead of you should you purchase one (£124.99 at ICARUS) and of course to point out if something is not right.

I had collected the plane from Icrus models on the seventeenth of July and had thought that a deadline for a maiden flight could be the eighteenth of August, which of course is the club fly-in, just over four weeks away! This for quite a few club members would be loads of time, but for me, this would have to be a trouble free build to get it ready in that time.

DAY ONE and the instructions start by saying that the canopy can be glued on, or screws are supplied if you prefer to make it removable, which was my choice. As I have said the canopy is ready to fit but when I found the area where I would normally insert the screws (no picture or advice in the instructions) it was just soft balsa. I set this aside to give it some thought = 0/10 so far! Keen to do something, and as it was starting to get late, I decided to join the (built up) main wings. A dry fit showed everything looked to line up very well although the wooden brace could perhaps been a slightly tighter fit but a nice touch was an alignment stud near the trailing edge to ensure everything was kept true until dry. Thirty minute epoxy was used to allow plenty of time = 10/10 and end of day one.

 

DAY TWO and I was keen to see the fit of the wings. When the tongue at the leading edge was inserted into the fuselage the trailing edge sat up around an inch but a quick check showed it was the excess epoxy needed trimmed from the tongue. Once cleaned up the wings were a perfect fit. The holes for the plastic wing bolts are pre drilled which lined up perfectly with the captive nuts. Time to check accuracy of alignment; the wingtip to the rear of the fuselage was two millimetres out, as I don’t plan to enter any IMAC rounds it will do for me. 10/10.   

 

  

  

 

 

Next was the fitting of the ailerons that have five Mylar hinges on each one, but not having any thin cyano, which is recommended I decided to do the bits and pieces I like most (the easy bits). Two servos in the wing and a nice touch was the double thickness of ply fitted for the servo screws, also a length of string pre-installed to pull the servo lead through. Undercarriage next, again the pre-installed captive nuts lined up perfectly to ensure a straight fit. The wheels and axels that are supplied looked good enough to handle any (not so) smooth landings, although a set of spats would have made things look so much better.

 

Next was to check the fit of tailplane and fin. With the covering removed at the slots both the tailplane and fin slipped in perfectly but on checking the tailplane alignment it was slightly down on the left side. Once aligned, the tailplane was glued in place (9/10). One important note before fitting the tailplane is to ensure the metal joiner for the elevator is in place as major surgery would be required to install it after, and NO I didn’t forget. I checked the canopy once again but still could not work out were the screws could go (0/10).

 

 

 

DAY THREE and before going to work I glued the fin in place, both fit and alignment were good (10/10). Later that night saw the rear wheel, and the engine mount installed. My choice of engine at the time was an OS55FX which is also the two stroke engine shown in the instructions. One important note here is to ensure the engine mount is fitted the correct way round or alignment of the cowl to the spinner will be incorrect and NO, I didn’t check = 0/10 – how was I supposed to know there was a right and wrong way round!

So after refitting the engine mounts (which are adjustable by approximately five millimetres) and engine, a quick check of the manual showed that the engine could be fitted within the cowl, but worried about cooling I decided to trim the cowl at the head. This was the start of an engine dilemma, the engine obviously was still situated within the cowl and just did not look right and I also think that cooling could still be a problem. This is one plane that a fourstroke would fit perfectly – need time to work this one out. Had another look at that piggin canopy but gave up (0/10).

 

DAY  FOUR and  I got my thin cyano, so on went the elevators and rudder, this is really starting to come together infact with the main wings, cowl and canopy (held on with sticky tape) it made me realise how much had been done in such a short time. The elevator push rod was next and this was the only part that I refused to use, for two reasons. The first was the wooden push rod, which resembled a mini telegraph pole, was far too big and heavy for a plane of this size but the main reason I did not use it was because of the flex in the seven inch wire push rod and with the thought of fitting a larger engine than the recommended 40 – 55 size, blow back on the elevator would be inevitable = 1/10 for effort.

 

Next was the rudder, throttle and elevator servo, again with a double thickness of ply fitted for the servo screws. Now it was the fitting of MY push rod into what seemed to be a maze of small cut outs in the three, or perhaps four, formers. In the end I found the best way was to remove the engine and insert the rod through the hole in the firewall meant for the tank, it took a bit of time working the rod through the formers and finding the slot at the tail but it all lined up fine (9/10).

 

 

 

 

SATURDAY- NDMAC DAY.  Having bought the plane on Tuesday and all this was done by Friday night, I took some time out and went flying on Saturday, which I am glad I did as it helped me decide on my choice of engine size. Peter has a kitted Acro Wot with an OS55 fitted and some other mad man, who shall remain nameless had fitted a super tiger .90 to his! Now the OS55 flew the plane very well and was capable of large loops etc, but just seemed to lack a tiny bit on top speed. Now it was the turn of the .90 size engine and although it didn’t quite pull the wings off it did infact pull out the clevises from the servo arm of the rudder, mental note; a .90 engine is too much power! Later that night I applied the decals and made measurements to help decide my choice of engine.

 

With most of the work done, the next few days were spent doing the smaller jobs one of which was the closed loop for the rudder. Everything is supplied to do this and there is even a piece of fuel tubing pre fitted over the clevis. With the hardware starting to get low I found the teeniest bag ever and in it were two small pieces of ply and four screws. As the ply was painted the same colour as the cockpit, I realised this was to be used for the screws to secure the canopy! Sorry Chris – remarked 10/10. After studying the pieces of ply for thirty minutes I still hadn’t a notion were to fit them – remarked 0/10.

Friday and Ian from Icarus phoned to say my Thunder Tiger Pro .61 that I ordered on Tuesday had arrived! So Saturday was spent re fitting the engine mount as even adjusted to its widest it was just too small. The cowl was trimmed, as was the fuselage to clear the silencer and it seemed, all of a sudden that the plane was very nearly finished, apart from the flaming canopy!

As the bottom of the plane is all yellow and not one of my favourite colours for   orientation reasons, black diamonds were cut from solartrim and applied to both the main wing and tailplane – 10/10 (of course).

 

With nothing left to do apart from installing the radio gear and setting up, I had to tackle the canopy. Two holes were drilled in the front section and hardwood glued to the inside of the fuselage at these points. The rear mounting lugs were located beside the pilot, so all I could do was trim away the soft balsa and again fit hardwood blocks for the screws. As these will be painted and with the canopy tinted I was happy with the result. If you have any better suggestions about mounting the canopy, PLEASE keep them to yourself!

          

With the build complete, it’s all down to the weather as to when the maiden will be, but I am hoping for Saturday the 4th of August, which is twenty days from when the plane was purchased.

 

THE GOOD BIT – FLYING!


The weather forecast for Saturday was to be 8mph winds with a touch of thunder. Now call me a chicken, but I really didn’t want to be standing in the middle of a runway pointing an antenna skywards if there was a chance of lighting, but decided to go even if it was only to put a tank of fuel through the engine. At Kirkistown the forecast for the wind was about right and there was no sign of rain.

Now obviously I had the wings fitted before, but had only tightened the wing bolts finger tight, this time as soon as any pressure was used the bolts refused to tighten and felt like it had stripped a thread. Other bolts I had with me fitted and were a completely different thread to the ones supplied – BEWARE!

After putting a tank of fuel through the engine and Stewart finished videoing for u tube, it was time to go.  Take off was as uneventful as I had hoped for although the rudder did seem quite powerful, making it a little tricky to keep a straight track before being airborne.  Three clicks of left aileron trim was the only thing needed for hands free flying.

I have found in the past that with some new planes having completed just a few circuits you feel completely at ease with, and although the Acro Wot felt like it was on rails in the turns, it seemed a bit “lively” flying straight and level. Stewart asked for a low fly-by for the video and my attempt was met with a “Are you going to do it low the next time” comment from someone. Having already switched to low rate for the elevator it was obvious that some lead was going to have to be added to cure this.
Time for the landing and as you can see on the video it was a roller coaster, even using the smallest amount of input.

 

 


I added 25grms to the firewall before the next flight and 'wot' a difference, low (and level) fly-bys were carried out with ease, rolls were quite axel, snap, spins and knife edge flight were better than my usual efforts and even a nice big loop needed no aileron correction at all. Landing was much better and controlled this time. Much more like what I had hoped for.

Michael Brown has flown his kitted Acro Wot for years so I was keen for him to compare the two, so he took the next flight with a warning for him not to show my flying up too much. Two circuits later and he is doing a rolling circle – so much for my warning! Michael again made comment about how well the plane sits in the turns, and after a nice landing said he liked it very much and how “Solid” it had felt in flight.

So with just a little fine-tuning to do (more lead in the front) I am really pleased it has lived up to all the hype and apart from the few problems mentioned, is a quality item which could be flown by anyone fully competent with a trainer.  

Thanks to Ripmax and Chris Foss for agreeing to make the Acro Wot an ARTF and like the Wot4 I am sure this will sell in very large numbers.

Talking of thanks I would like to say a big thanks to my wife Hazel, who had to answer my 3,654 questions on Microsoft Word and also calming me down when I thought I had deleted a nights work. Also thanks to Steven for using his magic on the layout and on my words to make it legible, and last but not least to Mr. Microsoft for inventing spell checker, without whom this review would not have been attempted.

Dennis Legge

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