How to Convert a Silverlit/airhogs Xtwin Into a Scale Model Plane

This instructable is about the converting a entry level RC aircraft such as the Silverlit/ Airhogs 'Xtwin' to resemble a real aircraft.Before we begin you should be aware that IT WILL BE VERY DIFFICULT, IN FACT NEAR IMPOSSIBLE, TO REBUILD YOUR ORIGINAL PLANE AFTERWARDS and the aerodynamic profile of real aircraft can rarely be scaled down to the size of a handheld model.The aircraft i made is based on the B25 'Mitchell', a US bomber from WW2,but you can emulate any type of aircraft you like(within reason).

2021 UPDATE: please note that this is a fun experiment for the classic aircraft fan, and I have (and certainly did not when I wrote this instructable) any serious RC hobbyist credentials.This project was based mainly on guesswork and a decade later it shows.If you are eager to enter the world of scale RC hobbying, consider emailing your local RC club and learning the ropes and costs involved from them.

It is likely that your model will not fly as well as the original RC aircraft, and may not fly at all without a lot of test flights and 'tweaking'.

Step One: Choose Your Plane

In the introduction, I mentioned that the plane you want to emulate could be anything within reason.Now, don't do what i did the first time i tried this and build a big and ambitious scale 747 or something similar because unless you really know what you are doing,it simply won't work.If you are doing this the first time I would recommend trying a simple,two engined propeller plane design.One VERY important thing to remember is that this will be nothing like the plane you are modeling it on.Sure,it may look like a Avro Lancaster etc,but if your building it this way it won't have the same shape at all.Do a google image search for "plans" of your plane,and if you cant find any there look on the profiles of the plane on sites such as wikipedia as they sometimes have ready produced profiles of them.
if you still cant find any try http://membres.lycos.fr/wings2/3vues/3vues.html.It's in french,but if you are not fluid in the language (I really was not when I wrote this) translate it with google's translator.

Step Two:planning

After youve found your plane you could just print it as it is,but i usually use ms paint to enlarge it to the actual size of my aircraft.There is no fixed size for the aircraft,but a little bit bigger than the size of the original xtwin is a sensible size for the engines to handle.In your plans you MUST at least have a front and side view of around the same length.

Step Three:the Materials

The vital material to have is extruded polystyrene,or depron foam as it os more commonly known.I got 5 sheets of it off ebay for around £3.00 plus p&p ($4.30).The polystyrene for packing material wont work unless you've got some way to mould it (i certainly haven't).

Step Four:cutting the Parts

Once you've printed off the plans (i dont have a working printer handy so i trace the parts of my moniter,something i wouldn't recommend)get your depron and with a craft knife cut around the plane templates.once youve done that,sand down all the wing surfaces with sand paper.If your depron is too small to fit all the plane on,cut out smaller bits of depron and line them up and attach them on both sides with tape and glue.The plane in the picture is not the b25,but its the same principle.

Step Five:the Electronics

The electronics on all xtwins are about the same.there are two motors (usually pushers)a receiver with charging port and the battery.Removing them is quite straightforward.the motors can simply be pulled off along with the wires.you will need to cut holes around the receiver and battery with your craft knife to get them out(be careful not to damage either,but especially the battery as it is likely to self combust if punctured).After you have them out,line them up and mark the positions on the depron fuselage cutout and make sure everything fits.The battery and receiver need to be placed towards the front of the plane to balance its centre of gravity.Place the motors at the back of the wings

Six:putting It Together

This is not the only way to put it together,but it is the simplest way i could think of for this instructable. Firstly,cut a slot about 3 mm wide where shown in the diagram to about halfway down the whole length of the plane on both pieces (as they are going to slot together,the important thing is to put the slots on OPPOSITE SIDES to each other.The plane in the picture is just a rough representation of any plane).Once you've done that,its simply a case of slotting the to pieces together,which is quite inexact,but it doesn't really matter if it slight sticks out either end.Now position the motors and electronics at the same places you marked before (on the underside of the plane)and secure them with some sellotape.If you are just making a profile aircraft you can stop here,but if you want it to have a 3 dimensional look to it you can cover it with lightweight paper(although bear in mind even adding paper can add 50g to the weight,leave the wings uncovered. Also you need to be able to get to the receiver quite easily to charge it and such).

Seven:test Flying

Once you have the plane put together with all the electronics installed,you need to sand down the edges with sand or glass paper.The wings need to be bent upwards at a 6 degree angle and more tape needs to be put on the nose and battery for protection(as the plane will often nose dive for the first few flights.When you do get round to test flying,fly it in a large indoor area or a grass field on a day with very little or no wind.Try gliding it for the first two flights and see the way it handles before trying a powered flight.

Eight:painting and Decals

if you've trimmed your plane and made sure it flies you can start painting your creation.You need to try and keep the weight down and choose the lightest paint possible,so spray paint is ideal(although you have to make sure it is either acrylic based or "foam safe" as some spray paints can dissolve the depron foam).I used citidel acrylic paint and spread it as thinly as possible over the depron while still getting an even coat.Decals can be added on with either acrylic and a smaller brush or permanent marker pens (use these sparingly).i haven't tried the airfix "rub offs",(ive forgot what you call them,) but they should work on top of paint.

Nine:now Go Out and Fly the Thing

After youve painted the plane your pretty much done.If the original plane you got the motors from had a elevator control you could mod that to open some bomb bay doors on it or get it to release a model bell x1 strapped under it or something.i might do some more instructable on mods in the near future.
i would like to acknowledge youtube member starbase1127 who has a great spitfire conversion tutorial and inspired me to build my own plane.I would also like to thank paul monteagle for his help and vast knowledge of fighter aircraft and finally i'd like to thank the good people at silverlit for building such a easily hackable rc plane.