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Hacker - Cap 232

www.hacker-model.cz

By: Dave Taylor

I purchased this ARF kit sometime ago and having now built and flown this aircraft I really wish I had made an effort to put it together quicker as it has taken sometime to get to the stage of flying it. I must be lazy at building.

Having said that I have spent quite some time experimenting with getting the cockpit area looking how I like it. Painting the pilot and the flat plastic cockpit floor so it looks 3D has taken most of the time. The result I think looks ok and enhances the plane's look both on the ground and when flown close in the air. Look on this web site for tips and hints on how to achieve this in your next project.

So what do you get in the purchase of this kit. Well you have a ready built and covered fuselage, wings, tail and rudder and you are presented with a good quality cowl and spats in glass fibre.

I decided early on that I would be powering this model with my trusty Yamarda 120 AC four stroke engine which is both powerful and reliable. Having decided on the power plant it was now time to work out where to place the servos and battery together with the receiver.

These were placed at the back of the cockpit opening so as to balance out the engine weight. The wings remove by using the plug in method. This uses a pre- installed and rather nice glass fibre tubes in both the fuselage and wings in which a smaller diameter aluminium tube slides in and you have the wings attached. To stop the wings sliding off there are two small hooks supplied which are screwed into the roots of the wings. These pass through into the fuselage then an elastic band is stretched between these. I have modified mine and I use two pegs which are pushed into the eyelet holes until tight then an elastic band stretched between which keeps them under tension so they shouldn't move, at the moment this does seem to work well.

As for radio equipment used, it is all Futaba, PCM receiver.

A S9303 Futaba servo is used on the elevator for smooth powerful and hopefully reliable control. Two S9102 servos for the ailerons, finishing off with 3001 for the rudder and throttle. This is all powered by a 1300 M.A.H. battery. Closed loop system is used for the rudder control and the rest is all controlled by push rods. With all this positioned at the rear of the cockpit hatch it balances spot on the indicated C of G, 100mm behind the leading edge.

The fuel tank is situated around the CG on two spruce rails and is held in place keeping it forward against the stops using elastic bands. The pressure fed fuel system has no problem in coping with length of fuel line between tank and engine. The kit is supplied with a nice set of Total decals which are self adhesive type, but as you can see I had mine made up in the "glue-it.com" logo from a local sign writing firm.

The instructions supplied with the kit are more than sufficient for the average modeller and are written in Czech and English. They are both clearly written and very informative and if you have built a few models before you should have no problems at all. A nice touch I thought is the spare part list at the back which gives you all the relative part numbers.

The kit is supplied with control horns, push rods, screws, nuts and bolts. I used most of these but like most modellers we have our own way of doing things re hinges and horns!


Test Flights

After assembling the Cap at the field, I checked out the radio with a range check. Checked the batteries for power and fueled up. I walked around the model checking wings, ailerons, rudder and elevator for security one last time. I then started the YS120 and if you get it right it fires up on the first flick, or pull over as I usually hand start this engine. Ground handling of this aircraft is good as long as you hold full up elevator and don't try to go to fast. Once lined up you are ready to go. On opening the throttle gently you apply a little right rudder to keep things straight and gently easing off the up elevator you find that by the time you have reached half throttle it's wanting to fly.

We are airborne and climbing on throttle at a very respectable rate and I find myself closing the throttle a little to turn down wind, the trim seems ok and the response to the controls is smooth, but solid and the Cap sits rock steady.

OK so lets turn and head into wind and we advance the throttle we climb a little and do some circuits just to get the feel of things.

General handling seems good, so now lets check out the stall characteristics having gained height and into wind. We shut the throttle and hold the flight path level by increasing the up elevator. Firstly as the speed decreases with the nose high the aircraft mushers then with more elevator it stalls, slightly left wing down. That's nice. Let's gain height and try a spin. We do the same again but this time as the nose drops to the left we apply left rudder and around we go spinning, rotating nicely and not to quickly. Yes this looks good. After four turns it's time to neutralize both elevator and rudder and it stops after half a turn. Having completed this exercise a few times both to the left and to the right, with the right stopping just a little quicker, it's time to try them inverted. These spins and exits are just as good with the rotations stopping in under a turn.

We now move on to a side slip which is where we have crossed controls eg right rudder and left aileron. This we use to lose height and speed on the approach to land and again the Cap handles these beautifully.

So now having landed we go over the airframe to see if there is anything that has come lose or needs adjusting before we fly again. From this first flight the Cap handles well. It has a good power band. It tracks nicely and with the exponential - 28% on elevator, rudder and ailerons it all seems alright.

We now refill the fuel tank and check the battery with a checker, as this is a new battery and get ready to fly again. With the elevator, rudder and ailerons all set to give maximum deflections and with the exponential set it's time to see just how good this Cap is at aerobatics. Is it going to be able to out fly my capabilities? Lets see what its like.

Lined up on the runway and opening up the throttle we have no trouble keeping it straight as the big rudder copes easily with any swing to the left. Once it is rolling full up elevator can be eased off and the airplane is left to roll on its main wheels with tail up for a few yards, before a gentle back pressure is used to lift from the ground. A steady climb is established up to a comfortable height where we turn down wind and gain height to experiment with the controls.

Now having settled into level flight we first try the ailerons with maybe half deflection. This produces a reasonable rate of roll, quite an axial roll with little yaw and little pitch so the differential built into the controls is just about right.

OK so now lets try a full deflection roll and this is a very quick roll and first attempts both left and right I over shoot the wings level finish, but only just and after one or two more attempts I can stop ok. The Cap sure does rotate quickly. The main noticeable point about the rolling manoeuvres with this plane is that it can be started and stopped when rolling very quickly due to the light wings as there is little weight to stop.

Four point rolls and any hesitation rolls are very pleasurable to perform using top rudder to keep things looking straight and level and I must say that you feel very happy and confident when flying this model.

Stall turns are very nice to fly with the power and response you have at hand and that large powerful rudder with which to yaw it around with. These large controls eg ailerons, elevator and rudder are all very effective right down to very low airspeeds and it is this together with the exponential which makes it handle so pleasantly indeed.

On later flights I have found that you can drop into some nice looking flat spins both erect and inverted and these are easily stopped and when performed correctly very little height is lost.

Flick rolls are performed with a brisk application of elevator either positive or negative using the rudder in the direction you want to go and ailerons to stop on line.


So how did the Cap 232 full size version evolve?

It's lineage goes back to the Cap 21 this is a 200 hp all wood aerobatic airplane which Eric Muller flew in the 1980 World Championships. Later this developed into the 230 which looked similar but was powered by a 260 hp Lycoming. This gave it better vertical lines which was the way that aerobatics was going.

There then followed the 231 powered by a 300hp Lycoming.

The Mudry company decided a carbon fibre wing was required as these do not twist under load when flicking or rolling fast and weight for weight they are much stronger and so the 231 EX was born. EX standing for Walter Extra built wing.

Cap Aviation now build the Cap 232 and it is proving to be a very popular aerobatic mount with pilots around the World. Firstly the wing is now made in house at Cap Aviation and is of carbon fibre composite giving it very good torsional stiffness which is required for a high rate of roll at 400 degrees per second and it is light compared to wooden wings therefore stopping better when rolls are 4 point as there is less weight. The fuselage is of a smooth finish as together with the tail plane they are wood. The ailerons use 75 per cent of the trailing edge of the wing and are balanced so they are very light to use. This aircraft has been carefully developed by French man Dominique Roland who was factory test pilot for Mudry Aviation for 14 years and it is to him that the constant development rest at the new company CAP aviation, who now build these aircraft.

I can only conclude that this Cap 232 kit from Hacker comes highly recommended and further flights have enabled me to explore the more exotic auto rotational manoeuvres for example tumbles, lomcovacs and zwirbelturm (or spiraling tower). A gorgeous machine and definitely the dogs wobbly bits!!!!

By: Dave Taylor