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Opinions on Cessna 340, 414 and 421



 
 
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  #11  
Old March 31st 04, 12:08 PM
Tom Sixkiller
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"One's Too Many" wrote in message
om...
If I were rich enough to afford a twin, I would like to buy a P337
Skymaster, not a 3xx or 4xx. Nasty wing AD hammer about to drop on the
heads of the owners of Cessna "conventional" prop twins. Oh, and if I
win the lottery, the only other Cessna twin I'd have would be a
Citation of course :-)


A P337 is essentially a twin engine Skylane; a 300 or 400 series is a cabin
class plane.



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  #12  
Old March 31st 04, 12:14 PM
Tom Sixkiller
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"Dude" wrote in message
...
Hmm, You raise an interesting point. Why is it that no one is making

those
planes anymore? Does everyone want turbine singles and twins instead?

I have seen that convrting the 421 to a turbine is becoming popular.

I know that turbines are safer than pistons, but I always believed that

the
difference in accidents between the turbine and piston twins was more a
matter of training than engine reliability.


Training and experience are definitely factors ("Professionally" flown vs
owner flown) but an engine failure, under the same circumstances, in a
piston popper might well be no big deal in a turbine.

I can't say for sure, but I don't think all that many piston engines have
full feathering props. Add the complexity of mixture control (and even carb
heat in some) and there's more work when that much more frequent failure
occurs.



  #13  
Old March 31st 04, 12:30 PM
Tom Sixkiller
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"john szpara" wrote in message
s.com...
A couple more commander questions. My best case scenario has the
following parameters:

1. Cruising speed 200+ kts (not just at the flight levels)
2. cabin class
3. potty
4. pressurized
5. price around $150k, +/- 20k
6. ceiling above FL240

Do any Commanders fit the profile?


The Commander's don't fit that, but neither do the 421's...not in that price
range (not one ready to fly without putting a lot more money into it to make
it airworthy, or one right up against engine OH).




  #15  
Old March 31st 04, 02:47 PM
Nathan Young
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On Wed, 31 Mar 2004 08:00:07 GMT, john szpara
wrote:

A couple more commander questions. My best case scenario has the
following parameters:

1. Cruising speed 200+ kts (not just at the flight levels)
2. cabin class
3. potty
4. pressurized
5. price around $150k, +/- 20k
6. ceiling above FL240

Do any Commanders fit the profile?


Those are tough requirements, but most are commensurate with a cabin
class twin.

1. Most planes (short of the low drag homebuilts) are going to have a
difficult time hitting 200kts (without running the engines at 100%)
below 10,000 ft. Flight levels and turbo are the way most airplanes
reach 200+ kts. As an example, I fly a Seneca II. Below 10,000, the
fastest you can go with 75% power is 175kts. At 20,000 75% power gets
190kts. Seneca's don't perform like the 3/4 series Cessnas, but the
concept translates. The 3/4 series twins will probably do 190kts
below 10k, and 220 in the 20s.

2, 3, 4. The 4 series Cessna twins meet all these requirements.

5. 150k is the LOW end of the range for the 3/4 series twins. Most
are listed with asking prices from $150 to $500k. Most in this price
range have high time engines, worn paint and interiors, and old
avionics. A cheaper alternative would be the Cessna T310Q or T310R.
Similar performance - 6 seats but without the pressurization and
potty. $150k will buy a nice one.

6. The pressurized 3/4 series Cessna's have ceilings from 25-30k
feet.

Keep in mind that the purchase cost of these twins is in relative
terms quite low. If a 421 was produced today, it would easily cost
$2M. (A 2004 Baron 58 is $1M).
Operating/maintenance/insurance/hangar costs on a 20-30 year old cabin
class twin can approach $400/hr. Also, have a look at
http://www.factoryengines.com and look how much a rebuilt GTSIO520 for
a 421 costs. $50k!

As others mention - the upcoming wing spar AD is a serious issue.
Many shops put the compliance cost at close to $50k.
Some additional info can be found he
http://www.twincessna.org/
http://www.aopa.org/whatsnew/regulat...incessna2.html
http://www.cessnatwinssparcorp.org/

-Nathan

  #16  
Old March 31st 04, 03:06 PM
jsmith
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Do some advanced research on fuel required and pax load before you buy.
(play with sample weight and balance for the loads you anticipate carrying)
If you want to fill the seats, your fuel load will be significantly
reduced to avoid overgross.
Short legs may not get you the performance you are looking for.

john szpara wrote:
A couple more commander questions. My best case scenario has the
following parameters:
1. Cruising speed 200+ kts (not just at the flight levels)
2. cabin class
3. potty
4. pressurized
5. price around $150k, +/- 20k
6. ceiling above FL240

  #17  
Old March 31st 04, 03:52 PM
Mike Rapoport
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"Tom Sixkiller" wrote in message
...

"Dude" wrote in message
...
Hmm, You raise an interesting point. Why is it that no one is making

those
planes anymore? Does everyone want turbine singles and twins instead?

I have seen that convrting the 421 to a turbine is becoming popular.

I know that turbines are safer than pistons, but I always believed that

the
difference in accidents between the turbine and piston twins was more a
matter of training than engine reliability.


Training and experience are definitely factors ("Professionally" flown vs
owner flown) but an engine failure, under the same circumstances, in a
piston popper might well be no big deal in a turbine.

I can't say for sure, but I don't think all that many piston engines have
full feathering props. Add the complexity of mixture control (and even

carb
heat in some) and there's more work when that much more frequent failure
occurs.



AFAIK all piston twins have feathering props. You probably meant
autofeathering though. Most of the safety difference is probably training
and the reliability of turbine engines. If you are ten times less likely to
have an engine failure, you are a lot less likely to have and engine failure
related accident.

Mike
MU-2


  #18  
Old March 31st 04, 04:09 PM
Mike Rapoport
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Default


"Dude" wrote in message
...
Hmm, You raise an interesting point. Why is it that no one is making

those
planes anymore? Does everyone want turbine singles and twins instead?

I have seen that convrting the 421 to a turbine is becoming popular.

I know that turbines are safer than pistons, but I always believed that

the
difference in accidents between the turbine and piston twins was more a
matter of training than engine reliability.



Its both. The relability of turbines is probably 10x greater than piston
engines so even if the pilots were the same, turbine accident statistics
would be a lot better.

Mike
MU-2


  #19  
Old March 31st 04, 04:11 PM
Mike Rapoport
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I don't think anything fits all those requirements.

Mike
MU-2

"john szpara" wrote in message
s.com...
A couple more commander questions. My best case scenario has the
following parameters:

1. Cruising speed 200+ kts (not just at the flight levels)
2. cabin class
3. potty
4. pressurized
5. price around $150k, +/- 20k
6. ceiling above FL240

Do any Commanders fit the profile?

John Szpara
Affordable Satellite
Fiero Owner 2-84 Indy Pace cars, 86 Coupe, 88 Formula 3.4, 88 Coupe, 88GT



  #20  
Old March 31st 04, 04:19 PM
Tom Sixkiller
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"Mike Rapoport" wrote in message
ink.net...

"Tom Sixkiller" wrote in message
...
Training and experience are definitely factors ("Professionally" flown

vs
owner flown) but an engine failure, under the same circumstances, in a
piston popper might well be no big deal in a turbine.

I can't say for sure, but I don't think all that many piston engines

have
full feathering props. Add the complexity of mixture control (and even

carb
heat in some) and there's more work when that much more frequent

failure
occurs.



AFAIK all piston twins have feathering props. You probably meant
autofeathering though.


I hadn't even thought of auto-feather, but I was under the impression that
most piston twins wouldn't go to full feather (it's been 15 years since I
flew a piston popper twin).

Most of the safety difference is probably training
and the reliability of turbine engines.


Agree, but I'd say that loss of a piston engine would be much more
hazrardous than losing a turbine under the same circumstances (weather,
load, etc.) since a turbine usually has much more power available in the
remaining engine than a piston. And, yes, under high loads, the margins are
equally BAD.

If you are ten times less likely to
have an engine failure, you are a lot less likely to have and engine

failure
related accident.


Indeed, but, too, SEROC in a piston is possibly a negative number, while in
a turbo-prop it might be 800-1000fpm. Handled the same way, I can see that
what is a landing short of the runway in a piston twin would be a non-issue
in a turbine.

I wonder how big the gap is between the two types, from Vsse to Vsi/Vso (not
sure I'm phrasing that right).


 




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