I did a quick dirty linear analysis of a couple dosen similar
airplanes (Cessnas, Pipers, and Citabria). I found the T/O(over 50')
is roughtly equal to 120*WingLoad + 60*PowerLoad - 1000. WingLoad is
Weight/Area and PowerLoad is Weight/HP. So for a Cessna 150, if I'm
10% undergross, T/O will shrink by about 250' and 40% increase in
power will reduce another 250'. So that will just make it about 850'
with a full fuel useful load of me with one of my kids for a fishing
trip.

Is this very true that the T/F type is going to be about 1/4 lighter
than a similar all metal one in terms of empty weight?

The other question: how serious are the performance numbers for those
advertised homebuilts? I really believe the numbers for the certified
ones.

Jizhong

On 3 Apr 2004 18:48:20 GMT, Del Rawlins
wrote:

In
wrote:

I really like to fly 150/152 and it's much cheaper (half the cost).
You might be able to get a good project plane for under $10k and a mid
time o-320 for similar amount.

Another thing to consider is that one reason 150s are often so cheap is
that they usually have a ton of hours on them and are suffering from
neglect. I have recently been working on a 150 belonging to a friend
who bought it last summer and used it to get his private license. This
was a basically safe, flying aircraft when we started digging into it
but I have been amazed at the number of problems we found and are having
to repair before he can fly it again. I guess what I am saying is go
this route if you want to, but don't expect it to necessarily be as
cheap as you hope.

(I'm talking about treating it as a
homebuilt in China.) But it's not a good bush plane. I'm wondering
why.How can we shrink the T/O distance shrink by a factor of two?
Compared with a Cub, I think the wing area is similar. I figure it
must be the gross or the lack of power. So if I get a 150hp at the
front, what will be the T/O at the gross of 1600#?

The 150 just isn't designed for the bush mission. As for the wing area,
the Cub has more at 178.5sq ft while the 150 only has 159.5. Combined
with the lower empty weight (even with a larger engine) of the Cub, this
gives it a lower wing loading and way better short field performance.
The stock gross weight of the cub is also higher at 1750 pounds, and can
be upgraded to 2000 pounds with a spar mod kit.

One aspect I think you would do well to ponder is that of repairability
in the field. I don't know what the parts situation is like in China,
but I suspect that getting parts for a Cessna isn't going to be all that
easy. The Cub, and many homebuilts for that matter, can be readily
repaired in the field using basic shop equipment. You can just about
roll a steel tube fuselage cage into a ball and still make it as good as
new with simple tools and an oxyacetylene welding torch. A dentist of
my acquaintance has wrecked the his cub over a half dozen times and is
still flying that same airplane (no, I don't fly with him). If you
prang the 150 over there good luck getting some of the fancy formed
aluminum parts to fix it. It may not be a bad idea to buy a spare
airframe to take with you for parts.

If it were me, I would strongly consider buying a kit for something like
the Zenith STOL 701 2 seater and an engine. That airplane is known for
a fast build time, good STOL performance, and simple flight
characteristics. You will lose some baggage capacity and top speed, but
you will have an airplane with ZERO operating time (think: no student
landings) on it which is repairable in the field with simple tools. You
know this is true because people build the same airplane from plans that
way.

----------------------------------------------------
Del Rawlins-
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