Ratio of Hobbs to Tach for instruction w/tower

In article . net,
Matthew P. Cummings wrote:
On Sat, 03 Jan 2004 22:41:13 +0000, Ben Jackson wrote:
I assume you mean maintenance since that's about all done with tach time,

Scheduled maintenance (100hr inspections, possible 50hr inspections),
oil changes, oil consumption, fuel consumption, engine life, airframe
life, etc all scale with tach time.

If you then charge by Hobbs time there's a 'slop' factor in there
because Hobbs Tach. My question is: what is that factor? I was
hoping someone who had been involved in renting airplanes had an
estimate.

For example, let's say it costs exactly $45/hr wet Tach to operate a
Cessna 152. If you charge $45/hr wet Hobbs and the ratio is 1:1, you
will never break even (pay your fixed costs of insurance, storage, and
interest on the loan above and beyond hourly expenses). However if the
ratio is .85 Tach hours per Hobbs hour, then you will get about $8/hr
towards your fixed expenses. In that case you might break even around
600 hours, assuming about $5000/yr fixed expenses.

Since the margins are small, the factor makes a big difference.

Based on your website, are you planning on getting back into flying, or is
your site just not updated, kinda like how I do mine?

Oh, I just never update my website. I bought a 1965 Comanche 260 last
August and I'm about 2/3rds of the way to my instrument rating (checkride
on Feb 7 if the weather lets up enough to get the rest of my hours).

--
Ben Jackson

http://www.ben.com/