Opinions on a M20J

"Thomas Borchert" wrote:

Doesn't leaving the tanks partially empty cause problems with
condensation or something along those lines?

NO! That is another of the many OWTs in aviation
(old wive's tales). Cessna did extensive experiments in
a clima chamber. They could NOT produce any noticable
amount of water in a fuel tank no matter what they did to the
temperature.

Right. Obvious, if you think about it:

How much water is there in 10 gallons of air? In extremely wet
conditions (saturated air at 20 deg. C) there are only 14.7 g/kg of
water in the air. A cubic foot of air at SLP weighs about 34 grams at
20 C, 10 gallons is 13.37 cu. ft., so that gives about 455 g. of air and
about 7 g. of water.

--
Dan
C172RG at BFM

On Mon, 06 Sep 2004 06:53:15 GMT, "Julian Scarfe"
wrote:

I don't know what else you fly, Ron, but aircraft like the TB20, the PA28s
and most light twins seem to handle crosswind take-offs with rather more
comfort.

Sorry about that. I did some reinstallation and my signature got changed.
But I've got over 2,500 hours in a Mooney M20E. And I presently fly out of
a single runway airport with occasionally strong, gusty crosswinds. I've
not had a problem with crosswind takeoffs, either. Just hold the nose
down, aileron into the wind, and pop-off when ready to fly. Obviously on a
paved strip.

And if you are talking about a 2,000' (610m) runway with trees to the end,
then yes, I would not want to be based there, given a choice. But, at
least here in the US, I don't believe I've ever seen a paved, short runway
where the 50' obstacle was at the beginning of the runway.

Grass is another story. I've been into Lubec airport (65B) which is 2024'
(617m), grass, with trees right to the end. Landing was not much of a
problem. But takeoff was close to the trees, even at 150 lbs under MGW.


Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)

Steven Barnes wrote:




I co-own with 2 other people. So, it's our policy to top-off after each
flight, so the next guy doesn't get stuck with it. Plus the fact I've heard
partially filled tanks can allow condensation. Water & rust in my fuel is no
fun.

If you want the reduced performance of carrying all that fuel then that
is a decision you have to make.



Our club has a 182 with long range tanks. I can't understand that. With full
fuel in each plane, I can carry more payload than the 182.

Apples and oranges. My 182 has the long range tanks too, 84 gallons.
With full tanks I have 650 pounds left over. I can fly for 11+ hours
with that fuel, although I can't imagine doing that. It's all about
options. For my normal flying around here I usually have 30-40 gallons
in the plane. If I'm going more than a couple hundred miles I'll fill
it up.

On 5-Sep-2004, Thomas Borchert wrote:

Doesn't leaving the tanks partially empty cause problems with
condensation
or something along those lines?


NO! That is another of the many OWTs in aviation (old wive's tales).
Cessna
did extensive experiments in a clima chamber. They could NOT produce any
noticable amount of water in a fuel tank no matter what they did to the
temperature. There are only two ways to get water in your tanks:

1. it's coming in with the fuel from the truck or depot tank.

2. it's been raining and your fuel caps leak.


Actually, there is a third way. and that is the condensation referred to.
Here is how it works:

Through its vent(s), the tank is open to the outside atmosphere. If the air
is humid, that puts water vapor in the tank. If the air cools, the water
vapor will condense (just like it does on outside surfaces, i.e. dew). Some
of the condensed water on the inside walls of the tank will drip into the
fuel. The cycle can be repeated for many warming/cooling cycles if the
plane is not flown for a while. Result: some water in the fuel. That is
the reason why we drain the sumps before flight.

HOWEVER: Despite the actual, albeit minimal, risk of water in the fuel,
there are overwhelming reasons for generally leaving less than full tanks on
most airplanes. The primary one is that usually when you return from a trip
you have no idea of the cabin load that will be needed for the next trip.
This is particularly true if the airplane is shared by multiple pilots.
With our Arrow, for example, if we topped the tanks (72 gal) between uses we
would be leaving an airplane with the ability to carry only 2 or 3 people.
What happens if the next user (we have 3 co-owners) wants to carry 4?. So
we leave the tanks filled to a total of 50 gal (usable), for which Piper
conveniently provided an indicator tab in each tank. That leaves a shade
under 700 lbs useful load, i.e. a 4-place airplane (that still has well over
500 nm range with 1 hr reserve.) If a user wants more range and has a
lighter load, he simply adds fuel before takeoff.
--
-Elliott Drucker

I fly around the Southwest. Take off and landing with 25-30 knots of
cross wind is no problem.

That does surprise me. I'm coming to the conclusion that either:

a) you measure knots differently :-)
b) you accept different levels of risk
or
c) you have a technique that I will never master

I'm quite happy to accept that it's (c), but would still offer the caution
about xwind performance to a prospective M20J purchaser.

While many manufacturers choose to demonstrate 20 or 25 kt for
certification, Mooney gave the M20J the bare minimum 11 kt (0.2 Vso) max
demonstrated crosswind component. That suggests to me that crosswind
performance was not high on the list of selling features.

Those numbers didn't sound right so I checked my 1965 M20C (short
rudder) manual which lists a demonstrated crosswind of 15 kt (17 mph).
I bet the M20J is higher than that. I have landed in up to 20 kt
with not much rudder left. 25-30 kt, well, that's a lot. Could it be
done, I bet. I'll be happy to try it in your airplane; I just don't
like the thought of having to file an insurance claim for a prop
strike and the associated downtime.
Bob Miller

3) Its landing distance is greater than many compatible tourers: because the
airframe is clean, it floats. So for short fields it tends to be the
landing distance that is limiting. I wouldn't want to operate a M20J
regularly out of much less than 2700 ft as you don't have much safety margin
at less than that. If you have that and don't visit short strips very
often, no problem.

Usually, the only reason it floats is because folk come in at well over
1.3Vso. I would have no hesitation about being based at a 2,000' strip (at
sea level). Going into KBGR regularly, I rarely have a problem turning off
at the first taxiway (1100') and I'm usually off the ground from my home
base in about 1000', without using short-field technique.

Shoot, anybody that bases their mooney at a field longer than 1500' is
a sissy...(just kidding) seriously, however, you can make a 1000' turn
pretty easily in my M20C (it stalls at 50 kt, mid-weight approach at
65 kt). However, it's nice basing at a long runway for those windy,
low ceiling icy nights :-)

"Ron Rosenfeld" wrote in message
...
[...]
And if you are talking about a 2,000' (610m) runway with trees to the end,
then yes, I would not want to be based there, given a choice. But, at
least here in the US, I don't believe I've ever seen a paved, short runway
where the 50' obstacle was at the beginning of the runway.

I'm struggling to think of one myself.

However, I have seen many paved runways with 100-150' obstacles not very far
from the runway (500-1000' perhaps). These are roughly equivalent to a 50'
obstacle right at the runway.

Here's one of the "easier" examples of the above:
http://www.airnav.com/airport/W10

Pete

"Julian Scarfe" wrote in message ...
"Robert M. Gary" wrote in message
om...

4) Its crosswind performance is ugly, particularly for take-offs. The
undercarriage uses rubber disks for its springs, and the wing is very
low to
the ground. Hence any bumps and you lose any side force from the
wheels,
and you have a lot of lift relatively early in the take-off roll. If you
operate an M20J from a single runway airport in a windy part of the
world,
this may be an issue. If you only rarely have to deal with 20 knot
crosswinds, no problem.

I fly around the Southwest. Take off and landing with 25-30 knots of
cross wind is no problem.

That does surprise me. I'm coming to the conclusion that either:

a) you measure knots differently :-)
b) you accept different levels of risk
or
c) you have a technique that I will never master

I'm quite happy to accept that it's (c), but would still offer the caution
about xwind performance to a prospective M20J purchaser.

I tell you, once you get down into ground effect you just don't feel
the cross wind in the Mooney at all. Of course, I started my life
flying 800lbs Aeroncas so I'm used to really feeling wind.

-Robert

"Steven Barnes" wrote in message om...
Doesn't leaving the tanks partially empty cause problems with condensation
or something along those lines?

The only time I've ever found water in my tanks was when an IA didn't
properly adjust the caps after replacing the O-rings. As a general
rule, my partner and I agree to never leave the plane with more than
15 gals per side. Sometimes we leave it will much less. My theory is
that if your flight is so full of danger that you need to land with 3
hours of fuel, you probably should consider not going. We also have an
on-board fuel computer. The performance of a Mooney with 30 gals of
gas is WAY better than a Mooney with 64 gals. Putting 64 gals of gas
in a Mooney is like using a Corvette to pull your boat. It just makes
it slow. We use a stick to measure the tanks, I've never found the
computer to be off by more than 0.2 gals.

-Robert

I fly around the Southwest. Take off and landing with 25-30 knots of
cross wind is no problem. The plane sit so low that you don't even
feel the cross wind in the flare.


I landed a C - Model Mooney in a 52 knot quartering headwind in Gage OK. It was
not easy but didn't make palms sweat. A 40 knot wind in a Cessna is about the
same.

In the panhandle of TX - OK the windsock is made out of a log chain. This is
the reason you need a Bellanca if you are going to fly a single in the wind.