Budget Retracts - Anyone own a Sierra or Comanche 180?

On Sun, 5 Feb 2006 12:28:18 -0500, Capt. Geoffrey Thorpe wrote:

Wow, that's news to me - I flew a Beech Sport for a while. The only problem
I has with landings was that I had a hard time getting the hang of the flap
thingies (I was too used to slipping in with no flaps in a Cessna 120).

Don't recall any problem with bouncing once I got it to the runway. Perhaps
I just didn't know that it was supposed to be hard? Or perhaps, the
reputation exceeds the reality.

I *think* the porpoising tendencies started with the Sundowner / Sierra
series?

More weight in front with 180HP vs the sport 150HP would be my hypothesis.

Allen

wrote:

The
airframe on the PA24 is about 400lbs heavier than my PA28 IIRC, with only 150lbs more
gross. Sounds like a 3-place retract.

I can't disagree with that. But for many missions, that is just fine.


As far as fuel flow goes, just because you have a bigger engine doesn't mean
you need to cruise with it. With only 60 gallons on a stock PA24 though, it'd be a
little bit short on range.

60 gallons is fine for the Comanche 180. At roughly 10 gph, that is 6
hours, which is much longer than most people want to sit. The early
models of the 250 (1958 through 1960) also had 60 gallons, which is not
enough at 12 to 14 gph, particularly for IFR trips. After 1960,
virtually all the 250 and 260 models had 90 gallons. Many of the pre
1961 aircraft have added tip tanks for an additional 30 gallons and a
gross weight increase of 200 pounds (less for post 1960 models). There
is also a baggage compartment tank available (20 gallons).

I agree with you that the Comanche 250 is a fine machine. It was my
choice. But the OP specifically mentioned a Comanche 180. The 180 also
has its place and, in some circumstances, is a superior choice than a
Comanche 250.

Hank
Henry A. Spellman
Comanche N5903P

Hello to all. I am new to this board and have my own aircraft
maintenance business. I work on mostly Pipers but also a Sierra that
may be for sale soon. I think you would find that the 180 Comanche is a
fine plane but you need to have it maintained by someone who
understands the landing gear system. So many of the old ones have been
bellied in at one time in their past. The Sierra does have a roomy
cabin and a short CG range. I had to change the landing gear doughnuts
on this model and it's not a job I want to do again any time soon.
First of all, you have to rent a special tool from Beech and they want
a $2000.00 deposit before they will send it to you. I think it cost
about $200.00 to use it plus the shipping charges both ways. If you
don't change the doughnuts ($900.00 worth) when they are sagging, you
might find the gear don't fit in the wheel wells they way they are
supposed to. The gear may or may not extend all the way when you leave
the ground, and one or the other will hit the up lock bracket and stay
there, instead of snapping into place. I changed every oring on the
hydraulic system cylinders (at owners request) and found the retract
cycle went from over 30 seconds to 14 seconds. Someone had put an oring
in the left cylinder that was too skinny to fill a groove on the
piston. I once did a prebuy on a Sundowner and found intergranular
corrosion on the left spar in two places. Aft side, lower web, near the
tip and just outboard of the fuel tank area. Beech has an approved
repair kit for this so you know it has been seen before. Also, don't
buy one of these planes with a fuel stain under the wings. Leaks can be
hard to fix in the wet wing fuel tanks. Finally, show me a plane where
they had to hang a ball of lead ballast on it and I'll show you an AD
note. This goes for other brands too.

A Sundowner is the easiest and most stable plane you will likely ever fly.
There is one thing that really makes it a delight. When you are landing,
dial in 75 kts on final using the trim. The trim will maintain the
airspeed. Use the throttle for altitude. When you are in ground effect,
slow up and pull back slowly until the runway disappears, and hold the yoke
back in your lap. If you use full flaps, you can stop in a few hundred
feet.

Thr thing about porpoising is related to landing too fast, and then letting
the nose slam down while you are peering out over the nose looking for the
runway. It's not the plane's fault, it still thinks it's flying.

One nice thing that is rarely discussed is that it is almost immune to
crosswinds. It's big and heavy, and doesn't get blown around much. The
demonstrated cross wind is not that high, but I think it can be landed
safely with a considerably greater crosswind.

You won't break many speed records, and headwinds can be frustrating. I
think if Beech put a bigger engine in the Sundowner, like they did with the
earlier Super Musketeers, they could sell them today.


"A Lieberman" wrote in message
...
On Sun, 5 Feb 2006 12:28:18 -0500, Capt. Geoffrey Thorpe wrote:

Wow, that's news to me - I flew a Beech Sport for a while. The only
problem
I has with landings was that I had a hard time getting the hang of the
flap
thingies (I was too used to slipping in with no flaps in a Cessna 120).

Don't recall any problem with bouncing once I got it to the runway.
Perhaps
I just didn't know that it was supposed to be hard? Or perhaps, the
reputation exceeds the reality.

I *think* the porpoising tendencies started with the Sundowner / Sierra
series?

More weight in front with 180HP vs the sport 150HP would be my hypothesis.

Allen

On Tue, 7 Feb 2006 16:44:40 -0500, LWG wrote:

A Sundowner is the easiest and most stable plane you will likely ever fly.
There is one thing that really makes it a delight. When you are landing,
dial in 75 kts on final using the trim. The trim will maintain the
airspeed. Use the throttle for altitude. When you are in ground effect,
slow up and pull back slowly until the runway disappears, and hold the yoke
back in your lap. If you use full flaps, you can stop in a few hundred
feet.

Add in the droop wing tips I have on my plane, and it is stable as a table.
Only thing above I do differently is fly final at 68 knots unless I am
doing an ILS, which I go at 90 knots down to the middle marker.

One nice thing that is rarely discussed is that it is almost immune to
crosswinds. It's big and heavy, and doesn't get blown around much. The
demonstrated cross wind is not that high, but I think it can be landed
safely with a considerably greater crosswind.

Its funny you mentioned this as I posted my experiences on
rec.aviation.student on going out in direct Xwinds of greater then 15
knots. I was extremely pleased how the plane handled, and here I thought
it was me *big smile*.

You won't break many speed records, and headwinds can be frustrating. I
think if Beech put a bigger engine in the Sundowner, like they did with the
earlier Super Musketeers, they could sell them today.

You mean that the Super M's had more then 180HP?

Allen

On 5-Feb-2006, "Doug" wrote:

You will be paying a big price for retract, in initial cost,
maintenance and insurance. Extra speed for 1 to 2 hour trips doesn't
amount to much.


If you fly over 100 hrs/year the savings in fuel costs with RG compared to a
FG with similar performance will more than offset the added costs for
maintenance and insurance.
--
-Elliott Drucker

wrote:
On 5-Feb-2006, "Doug" wrote:


You will be paying a big price for retract, in initial cost,
maintenance and insurance. Extra speed for 1 to 2 hour trips doesn't
amount to much.



If you fly over 100 hrs/year the savings in fuel costs with RG compared to a
FG with similar performance will more than offset the added costs for
maintenance and insurance.
I'd really like to see some number to support your conclusion. By my
estimates 100 hrs * 11 gals per hour = 1100 gal per year. RG decreases
fuel need by 5% or 55 gal * $3.50 = 192.50 per year in fuel savings.
From the numbers throw about by my aircraft owning buddies the delta in
ownership costs for a retract are much more then that.

Assumptions in above: Fuel burn is about the same for 180HP engines in
Comanche 180 and 172s with 180HP engine. Increased speed reduces need
for fuel by 5% by higher speed in cruise, climb fuel burn is the same.
Big YMMV is added

wrote:
On 5-Feb-2006, "Doug" wrote:


You will be paying a big price for retract, in initial cost,
maintenance and insurance. Extra speed for 1 to 2 hour trips doesn't
amount to much.



If you fly over 100 hrs/year the savings in fuel costs with RG compared to a
FG with similar performance will more than offset the added costs for
maintenance and insurance.
I'd really like to see some number to support your conclusion. By my
estimates 100 hrs * 11 gals per hour = 1100 gal per year. RG decreases
fuel need by 5% or 55 gal * $3.50 = 192.50 per year in fuel savings.
From the numbers throw about by my aircraft owning buddies the delta in
ownership costs for a retract are much more then that.

Assumptions in above: Fuel burn is about the same for 180HP engines in
Comanche 180 and 172s with 180HP engine. Increased speed reduces need
for fuel by 5% by higher speed in cruise, climb fuel burn is the same.
Big YMMV is added

John Theune wrote:
: I'd really like to see some number to support your conclusion. By my
: estimates 100 hrs * 11 gals per hour = 1100 gal per year. RG decreases
: fuel need by 5% or 55 gal * $3.50 = 192.50 per year in fuel savings.
: From the numbers throw about by my aircraft owning buddies the delta in
: ownership costs for a retract are much more then that.

: Assumptions in above: Fuel burn is about the same for 180HP engines in
: Comanche 180 and 172s with 180HP engine. Increased speed reduces need
: for fuel by 5% by higher speed in cruise, climb fuel burn is the same.
: Big YMMV is added

Not to be too argumentative, but 5% might not be the right number. A quick
example:
http://www.risingup.com/planespecs/i...plane432.shtml
http://www.risingup.com/planespecs/i...plane427.shtml

That's a PA-28-180 vs. a PA-28-180R. Cruise of 119 kts vs. 141 kts. That's
18% improvement in speed. Others are similar around 15%. So, multiply your fuel
savings by a factor of 3 and you get $600/year. That's starting to sound more in line
with the additional costs of a gear swing every year, some more lube, and a
replacement part averaging every 5 or so.

Just food for thought.

-Cory

--

************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************

wrote:
John Theune wrote:
: I'd really like to see some number to support your conclusion. By my
: estimates 100 hrs * 11 gals per hour = 1100 gal per year. RG decreases
: fuel need by 5% or 55 gal * $3.50 = 192.50 per year in fuel savings.
: From the numbers throw about by my aircraft owning buddies the delta in
: ownership costs for a retract are much more then that.

: Assumptions in above: Fuel burn is about the same for 180HP engines in
: Comanche 180 and 172s with 180HP engine. Increased speed reduces need
: for fuel by 5% by higher speed in cruise, climb fuel burn is the same.
: Big YMMV is added

Not to be too argumentative, but 5% might not be the right number. A quick
example:
http://www.risingup.com/planespecs/i...plane432.shtml
http://www.risingup.com/planespecs/i...plane427.shtml

That's a PA-28-180 vs. a PA-28-180R. Cruise of 119 kts vs. 141 kts. That's
18% improvement in speed. Others are similar around 15%. So, multiply your fuel
savings by a factor of 3 and you get $600/year. That's starting to sound more in line
with the additional costs of a gear swing every year, some more lube, and a
replacement part averaging every 5 or so.

Just food for thought.

-Cory

--

************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************

Very good, I was hoping somebody could come up with better numbers then
I had. It looks like from your numbers the fuel savings come close to
the extra maintenance costs so the insurance costs would swing the
balance toward the FG model cost wise. I think the extra "sex appeal"
of the RG might swing it back toward the RG side, but bottom line you
can't argue for the RG just on cost savings over FG.