Avionics

[James Roc]

As a prospective helicopter purchaser but still a novice could you help to shed light on the following products and whether there are better and more up to date models available...thank you!

King KY196A
KT76C with alt. encoder
KX155 with K1203

Whats the difference between a Slip indicator and a Turn indicator and are they necessary?

James.

[widgeon]

Garmin 430 with a 106 CDI can replace the KY196 and KX155 , . and you get GPS moving map thrown in. they also make a transponder. If you go with an all garmin panel ( including audio) they give you an extra discount.

On second question I have heard em called turn and bank and turn and slip indicators not sure if they are the same some helicopters require them for night vfr ( EC130 anyway ).

[Robbo Jock]

A Turn Indicator indicates that the aircraft is turning, i.e. its heading is changing, a Slip indicator indicates that it is slipping, i.e. that its nose is not pointing in the direction of travel.

A Turn Indicator is generally some form of gyro, mounted such that as the aircraft changes heading, the gyro attempts to point at the same bit of space which exerts a force on a "suitable series of springs and levers" that then moves an indicator on the instrument face.

A Slip Indicator is a ball in a tube that slides out to one side or the other depending on which way the aircraft is skidding, or a piece of string stuck on the windscreen of the aircraft that gets blown one way or the other by the air stream hitting the aircraft's nose.

As for avionics - sorry, no idea. But the Garmin 430 does look good in the ads (and Pilot magazine had a review of one recently, very favourable).

[PPRUNE FAN#1]

James, if you are looking at a particular helicopter with that avionics package you can rest assured that they are fine, quality, top-of-the-line products that will most likely give you years of trouble-free service. They're just a little old. Technology has moved on and there are some incredibly capable products on the market now. The aforementioned Garmin 430 and 530 are tremendous in what they can provide in a single unit. However, the lack of such equipment should not queer the deal.

In the light helicopter range (R-22, Enstrom) it might be rare to find an electric turn indicator. It's really not that important for day-VFR flying. In fact, new Bell 206's come from the factory without them, unless you order the optional "flight instrument group." More important is a slip indicator, which every helicopter should have. As has been noted, it could be something as simple as a piece of yarn mounted on the nose.

[James Roc]

I've seen the 430 in operation on a EC120 and it's a lovely piece of kit but seemingly the moving map display is not as detailed as a Skyforce 3c,swings and roundabouts I suppose.All things considered,weight,price ($10,000+) I may just be better off with the original suggested package and having the machine as night capable as possible would be a good thing just in case...thanks for your help!:)

[ATPMBA]

There are Turn Indicators and Turn Coordinators. They both do essentially the same thing, they show you what direction you are turning and how fast, up to 3 degrees per second and they also have a skid indicator built into them.

The older style, Turn Indicator, has a vertical needle that stayed centered if no turn is present. On either side of the needle are markings called “dog houses”, if you are turning and have the needle under a dog house then you are turning at 3 degrees per second. Three degrees per second represents a rate at which your inner ear can detect a turning motion. Actually, your inner ear senses a turning motion at 2 ½ degrees per second. Most of these instruments have a placard on them stating “2 MIN”. This means that it takes 2 minutes or 120 seconds to turn the aircraft through 360 degrees of heading change, this is how they get the 3 degrees per second.

The new type is called a Turn Coordinator, it looks like a miniature airplane as viewed from the rear. It shows the same information, turns up to a rate of 3 degrees per second.
This is a more advanced instrument as it uses both roll and yaw information for the display. It displays rate of roll and rate of turn, not bank angle.

I have flown with both instruments and I prefer the Turn Coordinator. It seems the Turn Indicator was always wobbly and oscillating whereas the Turn Coordinator’s miniature airplane was rock solid.

In the States and electric Turn Coordinator can be purchased for about $500, this is cheap insurance if you do night flying or fly on hazy days. With some training you could keep a helicopter upright if you inadvertently entered IMC or lost the horizon.