|Ian Walker's Tips|
|A simple idea I have used on '40' size
models, but it does away with the problems of fixed nuts or removing
broken plastic screws. (If anyone says it spoils the models
appearance just say Airbus 321!)
Adjustable Ballast weight
When a model comes out nose heavy we need to add weight to the tail to get the C of Gin the correct position. After the first flights we may need to carry out minor adjustments. This is the system that I use.
I get a plastic tube with a cap, the sort that comes with pills or tablets in it. This is glued firmly into the rear of the model. Next I take a setscrew that will fit inside the tube and add enough nuts to get the balance in roughly the correct place. Note that adding washers and one nut allows more weight to be added in a given tube and allows finer adjustment.
After the initial test flights weight can be added or removed to adjust the C of G to its final position. Once satisfied everything can be epoxied in place
|My problem was how to fit an MDS28 Pro with mounting dimensions 38*15mm into an aircraft which had a non removable mounting currently fitted with an OS40 with mounting dimensions of 40.5*17.5mm. The new mounting dimensions are not close enough to open up the original holes and are too close for a simple spacer to be used. My solution, which could be used for other engines with slightly different mounting dimensions is shown in the diagram.||
Perfect Dowel Fitting
I have always believed that correct wing incidence is vital to model performance. Many low wing models fasten the wing to the fuselage with two dowels at the leading edge and screws at the trailing edge.
Making sure that the the wing dowels and holes line up perfectly to give the designed incidence can be a tricky task. To overcome this I have adopted the following sequence..
a) Fit the dowels in the wing as accurately as possible
b) Make two short tubes that are a close sliding fit over the dowels
c) Drill the former holes well oversize to the outside diameter of the tubes
d) Glue the tubes into the holes with slow setting glue
e) Before the glue has set fit the wing and ensure that it is at the correct incidence. Leave until the glue has set.
Take great care not to glue the wing to the fuselage. The film covering should protect most of it; some wax rubbed into the dowels will prevent them from sticking
Many modellers move their receiver from one model to another so a quick way of detaching the aerial from the rear fuselage is required. My idea provides that.
One can bond a length of drinking straw to the tip of the fin, this can be hidden by covering over with the normal covering material
An even neater is idea which prevents the aerial from snagging is to run it down straws in the fuselage and up the fin leading edge. This straw can also be blended into the leading edge
Low Force Clamps
Being a traditional modeller using balsa wood I often need a low force clamp to hold two pieces together while the glue sets without damaging the material
Normal clothes pegs (A) are too strong whilst house sitting for my daughter I came across a new type (B) which have a slightly lower clamping force . However, by removing the compression spring and replacing it with a suitably sized sponge rubber (C) the clamping force can be adjusted to suit.