Are pure mechanical Varios necessary

A question for the masses:

Is a mechanical vario a 'necessity'? Can I use the space in the panel for a much desired good compass?

The existing panel is full with the following, all of the 'bigger' size: altimeter, air speed indicator, PZL mechanical vario (which works very nicely) and two ANCIENT Cambridge electric varios, one set up for 'netto', but doesn't work properly. The one Cambridge that works is tied to the audio output. It, and the audio, are barely ok, and maybe next year, I'll replace the two Cambridge's with a Borgelt B-50. What I don't have is a good compass. There is a boat type spherical compass mounted on the canopy railing, but it is a pitiful excuse for a compass. Thank goodness for gps!!!

So, should I sacrifice the great PZL, that doesn't need a battery, for a compass?

Putting the compass on top of the glare shield is not an acceptable option. The glider is an LS-1d and has the two-piece canopy and my forward vision is already compromised by the forward canopy rail. I don't want to add something that will 'close the space' between the top of the glare shield and the canopy rail.

Comments? Suggestions?

No, I don't want to go out and buy 57mm (the smaller size) altimeter and cut a new panel. I'm not even sure that if I were to get all but the airspeed in 57mm and retain the larger PZL if there would be enough room in the panel.

thanks,

Ray Lovinggood Carrboro, North Carolina, USA

Cost may be an issue but getting a computer (lots of used ones are around) might be the best option. Most computers give a bearing/heading readout if connected to a GPS. This still doesn't get you around the compass requirement but it does at least give you a practical solution if that's what your goal is. I like the idea of a mechanical vario since at some point you will have an electrical failure and it at least gets you home.

Casey Lenox

I would keep the mechanical vario for redundancy. Knowing if the mechanical vario is on the required equipment list would guide you in that issue too.

From what I infer in your description of the other two varios, it would seem that one of them would be a candidate for replacement with the compass you need. If you feel that the investment required to make the neto functional would be wasted when you execute your planned upgrade, then remove it now.

Which compass have you chosen?

On 14 Feb 2002 02:34:47 GMT, Ray Lovinggood

Your sharp if you can get a panel-mounted compass to work right. I've tried a few times with various types including Hamilton, and they never did too well. There was always some metal a bit too close, or some electric interference. Had one where keying the radio made it spin.

I have removed my mechanical PZL vario and kept it on the shelf for when I may sell the glider. However I still use an two electronic varios. A Borglet B100 and a B40 for backup in case my main power dies. The B40 will run from a 9V transistor battery. IN the last 250hours of usage this has never happened to me though. It depends on how reliable your power system is. Compasses I find are almost useless to me. This partly due to the fact that I know the area I fly over very well anyway and I have GP navigation on board any way. The compass in my current glider is a small PZL. When I refilled it with fluid the other day it leaked out within a few days. I am tempted just to put it back in the glider empty just to be legal but useless.

'Ray Lovinggood'

Ray, I have some pictures of what can be done with small instruments in a small panel at http://www.serkowski.com/img/2002-0127-WetValley/0127- sangres-wave.htm

and I ended up putting one of those small PZL compasses on top of the glare shield. If this is too high for you, the height could be cut quite a bit by making a depression in the glare shield and placing the compass there. Might be a winter project there for me too.

Before getting the '26E, I had an ASW-20B and ended up sinking an Airpath compass in the top of the glare shield - cut the height by about 50%. Follow some of the other photo links on my site to see what that looked like.

-Tom ASH-26E 5Z

TWO rear mirrors - do you worry that much about being overtaken?

As for the compass question, I can't remember the last time I made use of mine. GPS and the sun work fine.

I don't know about that Ray... one is about as useless as the other.

My views. There are 3 questions:

1) Is a backup vario necessary?

Personal choice but I would always have one. Apart from electronic problems with Nav computers (thankfully rare) there is the possibility of pneumatic errors. I have had main vario problems twice and both were pneumatic failures - once with an old TE tube that kinked in flight and recently with a new glider in which the triple probe static source tube has detached in the fin. It is worth keeping the pneumatic sources for the 2 varios as separate as possible and our current glider main vario used the triple probe pitot and static only (electronic TE) whereas the backup (Borgelt B40) used the TE input only and so worked fine.

2) Does a backup vario need to be mechanical?

Not now that the excellent Borgelt B40 is available and affordable. Runs off a 9V backup battery and is a pressure sensor rather than volume sensor instrrument so, if you have shared pneumatics, there is less interference between the 2 systems.

3) Is a magnetic compass necessary?

I had a GPS failure (software) in a friend's glider in 1999 and we completed a good flight on map and compass that we have had to abandon for fear of airspace infringements without a compass.

If it is not possible to install an accurate panel or combing mount compass then a good quality suction mount automobile accessory ball compass can be kept handy somewhere and stuck inside the top midline of the canopy for emergency use. The benefit of being far away from the other instruments seems to outweigh lower quality of the compass itself and they work surprisingly well.

John Galloway

I've been flying with mirrors for many years now and find them invaluable when circling with other gliders. I can keep an eye on anyone behind me without needing to continually turn my head. Every time I get in a different sailplane I feel as 'vulnerable' as when diving a car without outside mirrors.

I would like I had mirrors in the club gliders I fly. In my opinion the most valuable case is not when circling, but when two gliders leave the same lift, one a bit earlier and lower than the other, the last one flying a little faster. None of both can see the other and they slowly become nearer from each other. It happened to me in the Alps once, during a flight where everybody followed the same classical path, and I was scared whe I discovered a glider overtaking me just above my head. Happily no harm.