Online cost of airplane ownership spreadsheet

[Ben Jackson]

For a long time I've been meaning to convert my cost of ownership
spreadsheet into a web page. Over the weekend I wrote a rudimentary
sc-to-html converter (sc is an ancient, terminal based spreadsheet).

http://ben.com/flying/costown.html

I've already filled the page with caveats and disclaimers in anticipation
of the tough rec.aviation audience. Constructive criticism welcome...

--
Ben Jackson
>
http://www.ben.com/

[Paul kgyy]

Handy worksheet. If you want true ownership cost, don't forget to
include opportunity cost, the lost investment income on capital
invested in the airplane. Also, you're a lucky fella if you can get a
thorough annual on a Comanche for $1200.

[Paul kgyy]

Sorry, I see down below that you did mention opp. cost.

[xyzzy]

Ben Jackson wrote:

> For a long time I've been meaning to convert my cost of ownership
> spreadsheet into a web page. Over the weekend I wrote a rudimentary
> sc-to-html converter (sc is an ancient, terminal based spreadsheet).
>
> http://ben.com/flying/costown.html
>
> I've already filled the page with caveats and disclaimers in anticipation
> of the tough rec.aviation audience. Constructive criticism welcome...
>

This is great. I've been working on my own spreadsheet (who hasn't :)
and have some suggestions:

Breakeven hours are cited as tach hours. I think most renters only
think in terms of hobbes (elapsed time) hours and it took me a bit to
realize that when looking at the results. After all when I look in my
logbook to see if I'm flying enough to justify it, my logged time is
hobbes hours. You might want to consider adding an entry for "breakeven
hobbes hours" just to make it clear.

An "annual total cost for the renter" entry would be nice so renters
could see that number as a total in one place, as is done for the
owners. It's one thing to see the owner's annual total as $9047, wow
that's a big nut to crack, but when I compute my renter's annual total
from the spreadsheet's assumptions it comes to $5340 and suddenly the
annual premium, while still significant, doesn't seem quite as
intimidating.

Also, consider figuring in club dues to the hourly cost of renting. Do
you figure them into the breakeven point?

Also maybe different insurance entries for renters and owners. Looks
like you're assuming insurance for a renter is $0 (and it is in my club,
which insures all members) but many renters purchase renter's insurance
which is cheaper than owners' but is a cost they should figure in.

I know you suggested adding opportunity cost to the Annual entry, but
why not go ahead and have an entry for that, so people with loans can
put in their monthly payment.

It's the start of a great tool. I hope you will continue to maintain it.

[Douglas Olson]

Ben, thank you for an attractive and easy-to-use spreadsheet.
Spreadsheets aren't hard to make; but they're hard to make user-friendly to
others.

Since you pre-plugged some numbers for a model I'm considering, let's
discuss how realistic they are for a Cherokee 140:

Fixed Costs/year
Insurance 1,500
Tie-Down 900 (at my airport)
Annual 1,200 ("minimal surprizes" for 100 hours?)
Total Fixed 3,600

Hourly Costs
Fuel 23.31 (7.9g/h x 2.95/gal)
Overhaul 10.00 ($20,000 / 2,000 hours; engine overhual only, not
prop)
Reserve 15.00
Total Hourly 48.31

At 100 hours/year that's $4,831 + $3,600 = $8,431, plus the capital and
opportunity costs of buying it.
Opinions?


"xyzzy" > wrote in message
...
> Ben Jackson wrote:
>
> > For a long time I've been meaning to convert my cost of ownership
> > spreadsheet into a web page. Over the weekend I wrote a rudimentary
> > sc-to-html converter (sc is an ancient, terminal based spreadsheet).
> >
> > http://ben.com/flying/costown.html
> >
> > I've already filled the page with caveats and disclaimers in
anticipation
> > of the tough rec.aviation audience. Constructive criticism welcome...
> >
>
> This is great. I've been working on my own spreadsheet (who hasn't :)
> and have some suggestions:
>
> Breakeven hours are cited as tach hours. I think most renters only
> think in terms of hobbes (elapsed time) hours and it took me a bit to
> realize that when looking at the results. After all when I look in my
> logbook to see if I'm flying enough to justify it, my logged time is
> hobbes hours. You might want to consider adding an entry for "breakeven
> hobbes hours" just to make it clear.
>
> An "annual total cost for the renter" entry would be nice so renters
> could see that number as a total in one place, as is done for the
> owners. It's one thing to see the owner's annual total as $9047, wow
> that's a big nut to crack, but when I compute my renter's annual total
> from the spreadsheet's assumptions it comes to $5340 and suddenly the
> annual premium, while still significant, doesn't seem quite as
> intimidating.
>
> Also, consider figuring in club dues to the hourly cost of renting. Do
> you figure them into the breakeven point?
>
> Also maybe different insurance entries for renters and owners. Looks
> like you're assuming insurance for a renter is $0 (and it is in my club,
> which insures all members) but many renters purchase renter's insurance
> which is cheaper than owners' but is a cost they should figure in.
>
> I know you suggested adding opportunity cost to the Annual entry, but
> why not go ahead and have an entry for that, so people with loans can
> put in their monthly payment.
>
> It's the start of a great tool. I hope you will continue to maintain it.
>

[Dude]

Ben,

I like the jokes in your notes. You have a good grasp of your audience,
newsgroups, and the way both act. Gratz!

My biggest nit is it seems you assume people pay cash. Even if I had it, I
likely would not pay off the plane completely. Monthly payment should be in
there. (I am perfectly happy to ignore opportunity costs since mostly I
lose money on investments anyway).

Second, having owned a leaseback, I can tell you that my Hobbs to Tach ratio
was closer to .80 than .85.
I would say .805 to be exact.



"Ben Jackson" > wrote in message
...
> For a long time I've been meaning to convert my cost of ownership
> spreadsheet into a web page. Over the weekend I wrote a rudimentary
> sc-to-html converter (sc is an ancient, terminal based spreadsheet).
>
> http://ben.com/flying/costown.html
>
> I've already filled the page with caveats and disclaimers in anticipation
> of the tough rec.aviation audience. Constructive criticism welcome...
>
> --
> Ben Jackson
> >
> http://www.ben.com/

[Bob Noel]

In article et>,
"Douglas Olson" > wrote:


> Fixed Costs/year
> Insurance 1,500
> Tie-Down 900 (at my airport)
> Annual 1,200 ("minimal surprizes" for 100 hours?)
> Total Fixed 3,600
>
> Hourly Costs
> Fuel 23.31 (7.9g/h x 2.95/gal)
> Overhaul 10.00 ($20,000 / 2,000 hours; engine overhual only, not
> prop)
> Reserve 15.00
> Total Hourly 48.31
>
> At 100 hours/year that's $4,831 + $3,600 = $8,431, plus the capital and
> opportunity costs of buying it.
> Opinions?

(I have a 1974 140)

$1,500 for insurance? fwiw - mine is something like $940.

Don't forget costs of upgrades.

Don't forget cost of oil change every 4 months or 50 hours, whichever
is sooner.

Every two years is the pitot-static check. What's that, something like $200?

Does your airport have any required fees for badges, background checks,
and other fear-of-the-boogieman "security" measures?

Some people take into consideration calendar time wrt TBO. So, based on
the lycoming recommended calendar time of 12 years, the overhaul cost
per year might be, say, $1667 rather than your $1000.

Otherwise, the numbers look pretty conservative.

Cost of money wouldn't be part of the calculation unless you weren't going
to spend that money on anything else except the airplane.

--
Bob Noel
no one likes an educated mule

[Mike Rapoport]

"Bob Noel" > wrote in message
...
> In article et>,
> "Douglas Olson" > wrote:
> Don't forget costs of upgrades.
>
> Don't forget cost of oil change every 4 months or 50 hours, whichever
> is sooner.
>
> Bob Noel
> no one likes an educated mule
>



Where did you get the 50hr/4 month figure?

I got the 50hr or 4 month recommendation from Exxon for oil change and the
stated reason was that oil has the capibility of suspending some water and
after 4 months it would become saturated and corrosion could then begin. I
recently change the oil in the Helio after five months with infreqent flying
and the oil analysis said "water=0" I am wondering if the four month
recommendation applies as much to airplanes which are hangerd and subject to
minimal temperature variation.

Any other opinions?

Mike
MU-2

[Ron Natalie]

Mike Rapoport wrote:

>
>
>
>
> Where did you get the 50hr/4 month figure?
>
> I got the 50hr or 4 month recommendation from Exxon for oil change and the
> stated reason was that oil has the capibility of suspending some water and
> after 4 months it would become saturated and corrosion could then begin.

Many people recommend 25 hours if you have no filter.
It's what the service information on my plane says.

>
>

[Bob Noel]

In article >,
"Mike Rapoport" > wrote:

> > Don't forget cost of oil change every 4 months or 50 hours, whichever
> > is sooner.
>
> Where did you get the 50hr/4 month figure?

The 50 hour figure is from the service manual for my cherokee 140.
I don't remember where the 4 month figure is from. But for my 140,
it doesn't cost much more to change the oil 3 times per year rather than
twice.

--
Bob Noel
no one likes an educated mule

[Mike Rapoport]

"Ron Natalie" > wrote in message
m...
> Mike Rapoport wrote:
>
>>
>>
>>
>>
>> Where did you get the 50hr/4 month figure?
>>
>> I got the 50hr or 4 month recommendation from Exxon for oil change and
>> the stated reason was that oil has the capibility of suspending some
>> water and after 4 months it would become saturated and corrosion could
>> then begin.
>
> Many people recommend 25 hours if you have no filter.
> It's what the service information on my plane says.
>

That make perfect sense but what Exxon is recommending is 4 months maximium
regardless of hours.

Mike
MU-2