G_E_2015_04_

PRODUCTS & SERVICES NEWS 2

APRIL

2015

FEATURED PRODUCT:

PROTECTIVE COATINGS

Have Nano coatings finally

come of age in Aviation.

The car and boat industry are using new technology

and processes to help improve their overall longevity

of their asset and surface performance. Could the UK

aviation industry adopt similar principles, Steve Allen,

the man behind Cavendish Aviation debates how the

industry could learn from others and how new

technology processes could take the aviation industry

up to new heights.

There are in excess of 10,000 aircraft registered in the UK and all

owners are charged to comply with the EASA rules concerning

maintenance. The standard of this varies but generally EASA standards

are, met but one area where it could be an awful lot better is the

condition of the exterior and interior.

While a clean and shiny aircraft is visually more appealing than a dirty

one, appearance is a secondary consideration in aircraft cleaning.

Appendix D of FAR Part 43 requires the airframe and engine to be

cleaned as part of the annual or 100 hour inspection. Dirt can cover

cracked or damaged components as well as trap moisture leading to

further degradation and corrosion, making it common sense and good

practice to keep an aircraft clean.

Cleaning of Aircraft should be carried out by specialists and therefore

is not a Sunday morning job and can be expensive. Furthermore

corrosion and water ingress to the structure is one of the most

important aspects to aircraft operators it is costly and time consuming

to correct.

CAP 562, the EASA and CAA Standard on air worthiness, in Chapter 12

we see it is very specific about cleanliness and very specific about the

removal of deposits and debris. If left to accumulate debris can and

will cause more drag and increase weight, ultimately resulting in loss

of speed and more fuel costs. This tends to be a gradual process

which goes unnoticed.

Therefore, the general cleanliness and wellbeing of an aircraft should

not be taken lightly and yet in my experience the GA community

continue to ignore this important issue.

Tie downs can bring you down

The real headache for most aircraft owners is battling with the elements

when storing aircraft on tie downs, where the constant exposure to

water and UV degrades the paint and the aircrafts components.

A typical sign that the gloss is breaking down is where bugs stick to

the gloss, which I’m sure every pilot has experienced and the white

powdery state of the paint which is oxidation.

Aircraft owners therefore are normally left with two options. Investing in

an aircraft hanger at approximately £5,000 per annum or re-spray at

around £8,000.00

Aircraft paints degrade and oxidise because of exposure to UV and the

weather over time. Minute surface defects develop caused by friction

through the air. This results in loss of sheen, discolouration or both and

more drag.

Once an Aircraft has reached this stage we know it has less perform-

ance, reduced responsiveness combined with declining fuel economy

and a tired appearance.

Traditional Approach

At this stage the most traditional industry approach is to cut back the

top surface using abrasive compounds to remove the dead and

oxidised paint, then using an oil based sealant like wax polish to finish.

Or in many cases a large investment in repainting the aircraft is needed

which is often over sprayed increasing the thickness. The aircraft we

have seen in some cases measured at >100micron.

Are these products and process for both older and new aircraft

delivering a long term solution to the aircraft owner? Are they delivering

real protection and enhanced performance to what is a very important

aspect of aircraft; the skin and surface to the air?

Ramp appeal is important to the Aviation Industry at all levels of aircraft

but particularly in the high end where protection of a high value high

tech asset is important to its owner. Traditional finishing is short term

and plain hard work.

Even new aircraft suffer

Given that most aircraft are manufactured in the USA and that the pre-

ferred supplier of paint there is Sherwin Williams in their specification

we see that they are limited to a 25 micron coating due to visibility of

stress marks and weight.

The surface durability of new PU finishes degrades within 3 years.

Therefore, the 3 year old aircraft will need a lift for appearance, weather

protection and durability reasons.

UV/ Water degradation in paint of any type is logarithmic after 3 years

and depending on world location has differing rates of degradation.

Restoration

With modern technology it is possible to bring these aircraft back to a

new like appearance without respraying and at the same time provide:

1. Chip and scratch protection.


2. UV / Water resistance.


3. Reduction in surface drag
   As an engineer as well as an aircraft owner and pilot of thirty + years,
   the science behind this technology has fascinated me.

In other industries such as the Marine, Space and Automobile industry

are actually making great strides to tackle this problem with the use of

Nano Surface Technology.

How can the aviation industry look to other

industries to tackle this problem?

In my professional career as an engineer I have worked with many

industries, spanning from military installations, and electronic manufac-

ture to the car manufacturing industry. The use of nano techniques is

what drives a number of the supporting technologies.

In other industries where protection and speed are required including

F1, nano technology is used. Interestingly the car racing industry suffer

with the same issues as the aircraft industry. They have a high invest-

ment vehicle that needs not only maintaining but continual aerodynam-

ic improvement in order to ensure speed around the track.

For example the F1 industry have found that by using crystal based

nano technology they no longer have problems such as burnt rubber

from cars in front sticking to the vehicle. This is very similar to the same

issue I mentioned earlier with bugs sticking to aircraft.

The Nano Technology involves, removing all contaminates and

oxidation to the paint surface and bonding a nano coating at molecular

level to a prepared surface. Resulting in a consistent crystal glossy

surface, > 90 GU. By using a crystal element within the process it not

only locks in the protection, (meaning no more wax based products)

but and in most cases better than the original paint finish.

Could a new approach take the aviation

industry to new heights?

With other industries already using this technology for protection and

drag reduction and high end asset preservation, I feel that the aviation

industry could follow suit.

At Cavendish Aviation have developed a process using nano

technology to resolve these issues. Interestingly, whilst extensively

testing this process, we also found that this technology is particularly

suited to perspex. This has resulted in the Perspex areas which swirl

over time due to the soft nature of the product now taking on a glass

like appearance and is scratch resistant.

The base products have been tested by accredited Laboratories to con-

form to FAR 43. We have also done some testing into surface drag and

how this could be improved across all aircraft. Surface drag is a

function of the boundary layer which since 1939 has been calculated

for any given airfoil.

Research in 2003 in the UCLA identified the potential of nano

technology in reducing boundary layer. We have found on the aircraft

coated thus far have all experienced a 4% increase in speed from the

previous condition and therefore for the same speed is a power

reduction and a fuel saving.

This reduction in drag is greater, the greater the cruise speed of

the aircraft at low altitudes. In our experience and case studies

demonstrate that the benefits and costs far outweigh the traditional

methods and the challenges that currently come with it.

I am excited about how this could change the shape of the aviation

industry as well as aircraft owners approach to the overall care of their

aircraft.

The overall process is labour intensive and must be carried out in a

controlled environment by trained operatives with a Part 145 CAMO.

We have constructed a purpose designed facility for this with 1000lux

LED lighting and controlled air quality.

In my opinion this process actually should form Part of the Annual

Check and ARC as the like humans the skin of the aircraft is actually an

important organ.

Steve Allen spent 22 years in the car industry many of them in paint

and 25 years in the aerospace industry many of them in nano technology.

He is now MD of Cavendish Aviation a RMO.

http://www.cavendishaviation.net

Nanoparticles chemicaly bond with the surface of the paint

Top and below - Oxidisation on paint and Perspex.

An aircraft that has been on tie downs, and has struggled to pass check A.

The hydrophobic properties of the coating.

Finished 1987 aircraft with NO respraying!

Wing with before and after - GU at start = 6, GU complete = 86.

56 PRODUCTS & SERVICES BUYER EUROPE APRIL 2015 WWW.AVBUYER.COM

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