elenasgrumpy,
I like the tach H9 makes its looks good that RCKENS mentioned, but if money is an issue the [link=http://www.hobbico.com/fieldequip/hcap0401.html]Hobbico[/link] tach is only $25.00 its a great way to start.

the first thing i do when i use to assemble a plane and bought a flight pack, I would remove the battery and replace it with a 4.8 nmh 1600 or better you can fly almost all day with it,and i would install a volt watch meter in the canopy to keep an eye on things.

I realy never used a volt/load meter until i got in to gas planes when having one was necessary to check 3-4 battery's at a time it's a must before flight.

I would highly recommend the investment into a good battery cycler,if you don't already have one, this gives you a good peace of mind knowing you have a good battery in your Baby!

Heres a link to the [link=http://store.xtremercproducts.com/voltwatch.html]Volt watch[/link] meter clean and neet