Friday, August 14, 2009

My First Heli Scale Fuselage : A109E Agusta US Coast Guard

I assembled my very first scale fuselage helicopter. It's an A109E Agusta US Coast Guard fuselage. The fuselage kit came with retracts (2 on the back and 1 on the front). The helicopter I used to fit into this shell is a Trex 450 SEV2.

Here are some pictures of my completed prized possession!

It is not easy to fit an entire heilcopter into the fuselage and I had faced various challenges along the way. I will describe these challenges along the way as I hope you can learn a thing or two from my experience.

First of all, you will have to remove the following items from your RC helicopter as these parts are no longer necessary in the fuselage.

1) Landing skids and skid pipes
2) Tail stabiliser + tail fin
3) Tail boom support
4) Canopy (of course! :))

You will need the following items and tools along the way:

a) Small file (for trimming)
b) screw drivers
c) 2 servos for retracts
d) Y-cable for connecting the 2 servos into a single channel (optional if you have a 8 or more channel receiver)
e) servo extension cables (unless your servos have very long cables)
f) weights to correct the CG (believe me, your heli will be tail heavy after assembly)

Challenge 1 - Setting up the retracts
The retract for the rear wheels are damn difficult to setup. Initially I used a HXT-900 9g standard servo for the rear retract but the servo blew out after a while due to the heavy load extended to the servo. So, I used a PowerTech 9g metal gear digital servo instead and this servo is strong and held the landing gear in place well.

For the front retract, I only used a Hitec HS-65 carbonite gear servo and it seems to do the job fine.

Challenge 2 - Tail
Before you pushed the helicopter into the fuselage, you MUST remove the tail assembly, leaving only the belt. Otherwise, your tail rotor assembly would be too big to go through the fuselage body.

Removing the tail assembly is easy, but putting it back together with so little room to screw the parts together is a challenge! And please make sure that the belt is turning the tail rotor in the right direction before you screw the assembly tight together!!!

The other challenge I had while fitting the helicopter into the fuselage is the tail. The pre-cut opening for the tail is a little too far back. The tail of the helicopter is unable to fully reach to the opening access. The reason for this is that there are also restrictions on how far back the helicopter can be pushed into the fuselage due to the obstruction of the rear retract servo housing compartment in the fuselage.

In the end, I had to do use a small file to trim the opening a little large in order to accomodate the tail .

Challenge 3 - Getting the right height
You have to remove the landing skids of the helicopter because your helicopter has to 'sit' in the fuselage. The kit comes with many small pieces of wood which you have to secure in place of your landing skid and you need to put the right amount of wood in order to ensure that your heli sits in the fuselage with the right amount of height so that the tail boom is extended as parallel to the back of the fuselage as possible.

So please measure the height you wanto achieve with the right no of pieces of wood you need to stack together BEFORE you start to epoxy/glue the wood together! I learned this the hard way. I simply used ALL the wood, epoxy them all together and then later found out that the helicopter was sitting too 'high' up in the fuselage and the tail boom was unable to insert into the fuselage without rubbing. I had to resort to cutting away the excess wood in order to get the right height! What a waste of time and effort! :(

Here is a short video of my completed Agusta A109E!

And here are the retracts in action!

No comments: