Polycarbonate or Acrylic?

Over the years, there has been much discussion around the suitability – or otherwise – of polycarbonate (often called by the Lexan brand name) or acrylic (often called plexiglass) for light sport and recreational aircraft windscreens. Of course, as with anything aviation, there are no simple answers as to which material is best. There are pros and cons either way.

Aeroprakt now offers screens using either type of material – 2mm flat sheet polycarbonate, with UV protection and a scratch resistant coating, which is shaped during installation; or 3mm acrylic pre-shaped to fit. Both types of screen do the job and should last many hundreds if not thousands of hours in service. However, there are potential drawbacks and provisos to the installation and maintenance of each type of screen which, if not followed properly can lead to damage, cracking or at worst shattering of the screen.

Arguments in favour of polycarbonate include:
– it is almost indestructible, even in thin gauges; in fact it is a major component of bullet proof glass!
– by any definition, polycarbonate sheet is very flexible and can be formed cold into even fairly complex curves;
– generally, polycarbonate tolerates drill holes and is more ‘workable’ than acrylic.

The downsides of polycarbonate:
– the main drawback to polycarbonate sheet is its susceptibility to damage from gasoline exposure, even small drips can start to destroy the material and lead to cracks, deformation and the characteristic ‘bubbles’ which seem to be inside the sheet, particularly where it is shaped and under stress. The edges of polycarbonate sheet are notably susceptible to this kind of damage, often resulting in edge cracking;
– some other types of chemicals, typically those used in cleaning products (eg ammonia) also cause similar damage to polycarbonate sheet;
– polycarbonate will slowly discolour due to UV light. However, UV coatings can delay this process and it can take at least 10-15 years to occur, especially if the aircraft is kept in a hangar when not in use.

In favour of acrylic screens:
– generally more scratch resistant than polycarbonate sheet, although scratch-resistant coatings on polycarbonate have improved a lot over the last 10 years or so;
– all but the worst scratches on acrylic can usually be polished out;
– acrylic is optically clearer than polycarbonate, with much less distortion, even around curves;
– generally, acrylic screens will tolerate a wider range of chemicals, including gasoline, without serious damage.

The downsides of acrylic screens:
– acrylic is much more brittle than polycarbonate sheet. As a result, more care is needed when installing to ensure the screen doesn’t shatter just as you install that last rivet!
– acrylic needs a wider margin around screw and rivet holes to ensure expansion does not cause cracking through chafing or expansion stress – if badly installed, an acrylic screen can crack due to the hot sun warming a cool screen with not enough clearance around the rivets;
– at least one bird strike on a Foxbat screen ‘bounced’ off a polycarbonate screen; it’s likely an acrylic screen would have shattered. However, a couple of other bird strikes have shattered polycarbonate screens.

Ultimately, the choice is yours. However, Foxbat Australia has taken the view that the thicker acrylic screen offers enough overall benefit to standardise it on all A22 and A32 aircraft supplied new in Australia. These advantages include its better resistance to fuel, less susceptibility to edge cracking and, last but not least, reduced noise in the cabin. The 3mm screen is also available as a retro-fit item on both models of aircraft – it’s relatively quicker to install than the 2mm flat screen but you do need a jig (which can be loaned).

There’s a great Kitplanes Magazine article here, which goes into more detail about both types of material:- http://bit.ly/2NNJ7eE

New Aeroprakt factory website

Aeroprakt has launched its new, modern website incorporating many easy-to-navigate and visually stunning features. It’s a great development from their old website which seems to have been around a long time!

In addition to all the information on the A-32 and A-22 aircraft, and essentials like Service Bulletins, there are many new photos and videos to see. There’s also an interactive map to help you find the country dealer nearest to you.

Some pages – such as ‘History’ are yet to be completed but don’t let that stop you exploring this exciting new site!

You can click here to link directly to the new site in English (you also have Ukrainian and Russian language options): http://aeroprakt.kiev.ua/en/

New control lock for Y-stick Foxbat

A22 control lock 01

A22 stick control lock – click photo for larger view

Foxbat Australia has been working with a professional aviation control-lock company to develop a new system for locking the single handle and Y-stick control version of the aircraft. The result is a secure method of locking the flaperon/elevator control stick, suitable for use when the aircraft is parked outside – overnight or longer. This system is not suitable for twin control yoke A22 aircraft.

You may recall that as well as instructions in the A22 Pilot Operating handbook (POH) a recent factory mandatory service bulletin advises that when a stick-control aircraft is parked outside, the metal lock-pin must be supplemented with control surface clamps to ensure there is no damage to the elevator rod-end connection due to wind gusts. However, while it is relatively easy to clamp the flaperons at the wing tips, clamping the elevator has proved more difficult.

Without access to suitable surface clamps, a number of owners have preferred to remove the lock-pin and instead use the seat belts to lock the controls when the aircraft is parked outside. Nevertheless, the inconvenience of continually adjusting the seat belts, after they have been used to lock the controls, may cause some pilots/owners not to lock the controls properly. Also, some owners do not like the elevator ‘up’ position which results from locking the controls with the seat belts.

Worse yet, some owners still rely on the lock-pin even in adverse conditions – risking potentially disastrous damage to the elevator rod-end connection.

A22 control lock 03

A22 stick control lock kit – click photo for larger view

The new control/gust lock system is an excellent solution to ensuring that your A22 can be parked safely outside in all normal wind conditions, without the need to use either the metal lock-pin, seat belts or surface clamps. It holds the flaperons in a neutral position with the elevator ‘down’.

The new lock consists of a red adjustable looped strap, which fits and tightens over the stick. This loop is attached to two forward extending straps which are positively anchored via ‘pin-and-eye’ fixtures (not press-studs) on each side of the centre tunnel. The eyes on the strap ends are quickly pushed into their locked position and are released by pulling down on the strap end. The loop round the stick is adjustable and is also easily tightened and released. Each part of the strap system is labelled ‘Remove before flight’ and can be easily attached and removed from left or right seats.

Installation is very simple, requiring only the drilling of an additional hole each side to accommodate the anchoring pin bolts – which also utilise an existing hole.

Now, here’s the good news: during the introductory period until the end of April 2016, the price will be A$55 including 10% GST. After the introductory period, the price will be A$75 including GST. This price includes everything you need to fit the system and full installation instructions. Postage will be charged at cost.

If you want one of these control locks, please email info@foxbat.com.au with your name and address to confirm your order. You can pay directly with PayPal or with your credit card via Paypal – we’ll send you instructions.

 

Borodyanka Fly-in 2015

BorodyankaIt’s good to view some fly-in aerial activity from the other side of the world – in this case, near Borodyanka (sometimes spelled ‘Borodianka’) which is located to the north west of Kiev in the Ukraine. Here is a very nicely made little video which captures well the feeling of a local fly-in. [Click the picture to see the video]

Sitting where I am, wrapped up in my warm woolies and scarf in the middle of a Melbourne winter, the clear sunny summer skies look very inviting! There’s an interesting mix of aircraft at this fly-in, from an aerobatic Sukhoi through various Cessnas to some offerings (of course) from Aeroprakt. CEO Yuriy Yakovlyev arrives in his personal A36 and there are examples of the A22, A32 and the seaplane A24. There’s even a short display by Aeroprakt with smoke trails from the aircraft…I must ask them to send me a smoke kit for my demonstrator.

Roll on summer in Australia!

Overseas visitor to Foxbat Australia

Jörg & FatenToday I met Jörg (‘George’) Stobel and his partner Faten at Foxbat HQ in Tyabb Airport.

Jörg has been involved with Aeroprakt since the early days in the mid-1990’s.  Originally based in the UAE (where he still has a home) he is now taking on the role as Aeroprakt agent for Thailand. Jörg also has a home in Phuket (life’s tough isn’t it?) and his demonstrator A22 is kept an an airfield near Pattaya, just south east of Bangkok. I’ve seen pictures taken during his flights between the two locations and they are straight out of a travel brochure – deep blue-green sea, little islets with trees down to the water and tiny secluded beaches.

Anyway, I took each of them for a short trip in the skies over the Mornington Peninsula here in Victoria. It was a lovely day, if a bit hazy, but I guess the views can’t really compete with those between Phuket and Pattaya…although both remarked on how green the countryside looks at the moment.

Jörg and his partner – who works with Etihad Airlines – are in Australia for a few days to ‘relax, unwind and chill out’.

It was great to sit and chat with them over a coffee about the early days of Aeroprakt and hear about the times while they were working to get the business going. But that’s over 20 years ago now and Aeroprakt is close to manufacturing their 1,000th aircraft. I will be offering spares and other service back up & support to Jörg while he is building his business in Thailand, and wish him every success.

At the weekend, Jörg  and Faten are flying from Melbourne to Sydney to visit friends but we’re hoping to get a couple more flights in before then – maybe up around the top of Port Philip Bay to have a closer look at Melbourne and the bayside.

Bush flying photos

Waipara River shingle bank

Waipara River shingle bank

Many thanks to Matt Dowdall, who submitted the first six photos to grace our photo gallery – see bottom RH corner of this page.

Matt, an A22 owner and pilot in New Zealand, sent me the pictures in response to an enquiry/comment on the post ‘Who needs a taildragger?’

Thanks, Matt