Quicksilver MX control system, airframe and fabric troubleshooting.

Quicksilver MX King Post and Nose Wire Update


Quicksilver MX King Post Tang and Nose Wire Failure.

It has been reported by several MX owners that the nose wire located at the front of the root tube and running down to the triangle bar has snapped on landing. This usually causes the A frame to collapse around the pilot. 


A possible solution to this problem is to replace the single wire, and tang, with the new style double wire and tang shown in the attached photo.



Plastic Tube Spacers used on Quicksilver and other aircraft to connect tubing to airframe.

Quicksilver MX plastic tube saddle failure.
The MX used several different sizes of saddles throughout its airframe. These saddles were generally used to help eliminate wear and tear on parts, by preventing them from 
rubbing against each other. 

Pilots have reported that these saddles have broken causing improper spacing, and or wear on parts. An area in which these saddles are located, which is critical to the flight characteristics of the MX is in the area of the horizontal stabilizer. 

If the saddles break in this area it causes the horizontal stab to flutter, in flight, which can be very disconcerting to the pilot. Also the horizontal stab is used to determine 
the correct angle of incidence from the tail to the wing, and the loss of these saddles can result in control problems. 

This is an area that should be regularly inspected and if any saddle is found to be cracked or cracking it should be immediately replaced. 


Another problem recently encountered on the MX is that of the fabric on the horizontal stabilizer becoming very loose. This generally results in the aircraft flying with a nose high attitude. If the fabric on your craft is loose it can be tightened somewhat by using a hot iron and passing it carefully and quickly over the fabric. If this does not work the fabric should be replaced, or the tail section updated to the new style which features a leading edge tube which joins back up to the trailing edge 
of the horizontal stab. 

Quicksilver MX Horizontal Stablizier and Tail Tube Support Kit

Another problem recently encountered on the MX is that of the fabric on the horizontal stabilizer becoming very loose. This generally results in the aircraft flying with a nose high attitude. If the fabric on your craft is loose it can be tightened somewhat by using a hot iron and passing it carefully and quickly over the fabric.

If this does not work the fabric should be replaced, or the tail section updated to the new style which features a leading edge tube which joins back up to the trailing edge 
of the horizontal stab. 

Quicksilver MX control System troubleshooting

Quicksilver MX rudder assembly

Quicksilver MX Rudder Assembly 

It has been reported by several MX pilots that the rudder frame (part no 40333) has hooked up on the upper tail wires, in most cases the aircraft had over 150 hours on them and the king post had been adjusted to or near the maximum allowable. 

The entanglements have been reported, on the ground during a take off run, on a rough field, and in the air, in turbulent flying conditions. When the frame was supplied from the factory it was usually longer than is necessary, and this could contribute to the problem. 

If you are flying an MX we strongly advise you check to make sure that your rudder frame can not come past the upper tail wires, and that your rudder frame is cut off flush with the bottom of the tension strut on the rudder. Also the retrofit tail boom kit has been found to help eliminate this problem.

Quicksilver MX Spoileron Horns
Early model MXs used a plastic tab to deploy the spoilers, these required considerable amounts of pressure to engage and generally just ended up stretching the deployment lines. 

Later models used a horn which worked well and allowed full deflection of the spoilerons. Another problem with early MXs was in the use of plywood to make the spoileron plates. These ended up rotting, or buckling over time. Later models used a bevelled 
aluminums plate.

Quicksilver MX Wing Ribs - Battens

Quicksilver MX Wing Ribs.

Early model MX instruction manuals came with instructions which told owners to install their battens with the plastic retaining tips so that they came out on the top of the wing. Pilots flying with them in this position found that the battens backed out of their pockets and in some cases into the prop. 

Later manuals had the owners turning the tips so that they exited the underside of the wing, and were held in place by air pressure and the trailing edge. Owners who have installed their battens the other way who didn't want to change simply drilled holes in the tips and tie wrapped them in. This worked well although in many cases the tips simply broke off where the holes had been drilled. 

It was also recommend that MX owners make a pattern from a new batten and then on a yearly basis check and rebend any battens that require it, to the shape of the new one. This can be done very easily using two pieces of plywood, the first as a base, the second the shape of the batten.

​When rebending the batten simply lock it in place between two pieces of wood, at its leading edge, and carefully rebend it around the pattern.

Quicksilver MX ultralight aircraft fabric Troubleshooting

The fabric used on the MX was Dacron Sailcloth. This material is very susceptible to UV light. Even if a pilot stores his plane inside, or uses wing covers the flying surfaces are still exposed to UV when flying. 

Tests have shown that the fabric can loose its strength in as little as 6 weeks in some regions of the country. To date I have found only two products effective in helping prevent UV degradation. 

They are Stits Aerothane, and EXTERIOR HOUSE PAINT. These coatings have extended fabric life from 1 to 8 years on craft located from Florida (1 & 2 years) to Ontario (8 years), when the planes have been left outside most of the time. 

Check out UV Protection 
Either process can be applied by gun, brush, or roller, with the gun doing the best job. The coatings are all very toxic to use and should be applied only after reading and following the instructions very carefully. 

Ultralight Aircraft Fabric Testing.

http://www.ultralightnews.com/ - Ultralight aircraft fabric testing. Testing your dacron sail cloth for UV damage. In this issue of the Light Sport and Ultralight Flyer we take a look at Dacron fabric used to cover many of today's ultralight aircraft.

We watch as eastcoatbeaver https://www.youtube.com/channel/UCFFE... shows us a very simple way of checking your fabric.

Then we go to Airventure and Steve Marhle shows talks to us about some of the things we should look for when considering buying or flying in an ultralight.

Then we visit with Bever Borne who shows us a more scientific way of checking your ultralight aircraft's fabric.