Hello Folk,
The following is a series of raw conversations regarding TCFG members' thoughts/experience with flying/owning early Turbine Model Aero Commanders. These conversations are sourced from the TCFG Chatlist in the early 2000's and are strictly the opinions of members at the time.
While I am sure the experiences discussed are still as relevant in 2015, it should be noted that some key members featured have since passed out of Commander ownership.
Wing Commander Gordon will undoubtedly recall the times...
Enjoy!
Cheers
Russell
VH-CAU
560E s/n 726
681
Although I have no first hand experience with the turbo Commanders I
do have some information prepared by a TCFG member that outlines the
differences in each model. The chart shows that the 681, with the original
TPE-331-43BL engines had the following performance. Cruse speed 240 kts.
Max. altitude FL 250, Max cabin pressurization differential 4.0, Fuel
capacity 337 USG, Fuel flow is #240 per engine, Engine HP 575, Engine TBO
2000hr, Gross weight is 9400 lb., Useful load 3100 lb., Produced from
1969-72. If the airplane has been upgraded to TPE-331-5 engines (717hp,
5400hr TBO) the performance would be much better. A 690 airframe, with the -5
engines, cruses 260KTS and the 681 should do at least as well. All other
figures would stay the same (useful load, fuel capacity, etc.)
Hope this helps. capt jimbob
I wish that were true, and I'm sure Sr. Calle does, too!
That chart was prepared by Dan Gryder, one of the contributing authors of the
Flight Group News, serveral years ago. Dan flew a 690-A, is now flying for
Delta. (Way to go, Dan!)
In my experience with the -43 powered Commanders, they do their best in the
16,000 to 19,000 ft. range, stuggle to get into the low 20s and end up
cruising more like a peppy 680-FLP; around 190 to 200 kts., and a few only
did 180 kts.
This may be due to the fact that the -43 series are getting on in years and
support is limited to Bob Hancock in Tennessee and I suspect lots of
components in the field are not up to spec. This NOT because of Hancock's
work, but rather the fact that the operators of -43 aircraft are "economy
oriented," to be polite, and defer much needed engine work.
The 681-Century I flew went like a stripped-assed ape; 250 kts, easily, had
to pull back to keep off the redline, marched right up to the mid 20s.
Sr. Calle's 681 is powered by -43BLs, which should help him some (the "BL"
model had better compressors and a higher operating temp range), but even the
-BL powered Tubo Commanders I've flown were lacking in high and hot
perfromance.
I'm still working on digging up realistic fuel and cruise numbers for a -43BL
powered 681, based on something other than my memory of operating them 3-4
years ago.
Keith S. Gordon
Second hand from memory, reported by the operators of 681's, which I evaluated to buy.
BL's 200/210 kts summer/winter, practically 16-19K operations
Century conversion -1 215/225 summer/winter, 18-22K operations
Super 1(-2 compressor on a -1) 230/240 summer/winter, 20-25K ops.
Fuel burns are all about the same #220-#240/side/hour at best altitude. Statute range improves w/ the later engines
Been monitoring the performance figures posted for the model 681, following
Alberto's request, albeit from a remote, wet, windy & cold small Island on
the other side of "the pond" and with a non-pilot, non-engineering
background.
Alberto, you have 681B-6049, HC-BPY, yes?
Capt Jimbob has posted figures which match with those published in the
"Rockwell Commander Aircraft Handbook" which was around in the mid-70s,
although:
Fuel capacity 286.5 gal. standard, 337.5 gal with auxiliary fuel.
Fuel consumption 410 lb/hr. @ 98% RPM
Range quoted as 1,296 nm
Best rate-of-climb 120kts
A number of 681s were up-graded to "Century Turbos", but these had
TPE331-1-151K engines, not the -5 (717.5shp) of the model 690, but all 681s
were built with the -43BL (575shp) engines, as was the 680W Turbo II. The
680T/V had -43/-43A (again, 575shp). What was the shp on the -1-151K?
Be interested to see what 'Wing Commander' Gordon comes back with. Has he
talked to a "stripped-assed" ape I wonder? I thought they only flew
Cessnas!
An idea! Any chance of us encouraging someone from people like
Garrett/Lycoming/Hartzell etc. to monitor our listbot? Could get some
useful feed-back from questions posed? Probably pie-in-the-sky,
but...........
Just to add to what Andrew so correctly stated (about Lears and 680 series
turbines), the -V and -W Turbo Commanders are "on condition" maintenance
schedules, which means you do an annual and IRAN.
No, that doesn't mean the Ayatollah signs it off. That's Inspect and Repair
As Necessary. That's a big budgeting difference from the 690 series that
have mandatory inspection intervals and component replacement times. (100 hr.
inspections; 5, 10, 12, year inspection/overhaul times, etc. etc. etc.)
The Hamilton-Standard props are (or at least, were, last time I checked)
on-condition, with no ADs. (no promises on the AD status.)
That *potentially* makes for an inexpensive operating budget ... but seldom
yields it in real life.
I don't want to slam the -43 series engines, nor the airframes they're
attached to, but here are some considerations:
With the -43 series, you are pretty much tied into one provider of support.
That would be Hancock Turbines in Tennessee. Well, at least there IS support
for them and he has a TBO extension program in place if you do get into one
of these models. He takes a 2000 hour engine to 3000 hours.
Next. (danger! opinion in progress) The -43 powered Turbo Commanders are
not well suited for high and/or hot operations. If you're East Coast or
Midwest based with a good runway, great! Go get one. You'll never have
trouble making IFR MEAs and the high teens for cruise are OK in those areas.
If you're western based with airport elevations and terrain what they are,
you'll feel limited by this series.
Next. Pressurization on the non bleed-air mod specimens: The Skydrol fluid,
3000 psi hydraulic system for the cabin supercharger is powered by what is
now a rare hydraulic pump. If there is an Achilles' Heel to the pressurized
680 Commanders, this is it.
Possibly Morris Kernick can work his magic and make some of these hydraulic
pumps appear ... but it's a hat trick for sure.
Oh - and these New York Airbrake hydraulic pumps extract about 45 hp. per
engine to operate. If you need to get off a short runway or get going on a
hot day, you should take off with the pressurization & aircondtioning system
OFF. Mmmmm, oh so nice on a hot day.
As for 20 series Lears ... Andrew was being diplomatic. They're lawn darts.
If ever there was a case of the Emperor's New Clothes, it's that series
Lears. I was typed in a Lear 25D and came to the opinion that the 20
series Lears are the second worst handling aircraft I've ever flown.
Stay away from the Lears, Paul. If you want to be kicked out of airports
for operating a straight-pipe turbojet, get a Jet Commander! At least it has
an honest wing.
What about the turbines?
I know we've got several turbine guys here and I'd like to ask
for opinions.
I'm beginning to ponder an oil-burner as a possible next airplane.
Obviously a Rennaisance 1000 would be dandy, but realisticly, I'd
like to learn more about the 680V/W, 681 airplanes. Given that most
of my flying will be personal with light business use, the pre-690
birds appear to be a nice fit. I've heard mixed opinions (without
much detail) on the 681. I understand that there are several engine
conversion options (Century and "Super" Century). Can anyone shed
further light on the various aspects of owning one of these models?
Chris, if you're looking at pre-690 Turbo Commanders, the best performer will
be the 681 Century. Did that surprise you? The one I flew either had the
engines dialed in wrong, or a terrible pitot-static error, but I had to pull
power back in the 12,000 to 18,000 range to keep from flying over the "barber
pole." It was fun. Got into the mid FL 200s all the time, no trouble.
Nice to have a native bleed air pressurization and 5606 hydraulic system as
well.
The options are a 680-T, V or W. If you get either of those with the
original -43 engines, you'll do well as you operate in the midwest. i.e.,
flat and moderatley long runways.
Expect performance to drop as temperature rises. In the warmth of
California's Central Valley in summer, I got a 680-V to climb to 16,000 to
18,000 and cruised at 190 to 215. To be fair, it had a squirrley set of
engines and I think it could have done better if they were rigged right.
It is true: In the long run an early Turbo Commander will cost the same as a
geared Lycoming ship but you will be shocked by the occasional component that
costs $8,000. (that seems to be the starting price for any part on a Turbine
airplane.)
The pre-690s are "on condition" maintenence. You do annuals, not 100 hour
inspections and scheduled overhauls of gear, props, 12 year, 15 year items,
etc. etc.
The Hamilton-Standard props are "on condition" as well.
You get reverse thrust for landings and ground handling.
As I've said before, if you get a T, V, or W without bleed air
pressurization, the biggest headache will be the high pressure hydraulic
pumps and a Skydrol hydraulic system.
The "Super Century" conversion you metioned is also known as the "Super Dave"
conversion STC's by National Flight Services of Toledo, Ohio. They placed a
later Garrett compressor section on the Century engine and really upped the
performance. To my knowledge, there's only 2 or so of these in service, I
could by way off on that. One, at least, is a photo ship in South America.
I bet you could slide into a V or W Turbo Commander for not too much money
and you'd get to come home wearing a new cologne your wife will hate: Eau de
Jetá -- but we love it, don't we?
Wing Commander Gordon
All back from Commander Nirvana / Scottsdale and back in the real world are
we? Too bad.
I made a statement about pre-690 Turbo Commander maintenance schedules and I
think I may have lead some to the wrong idea with my term "on condition
maintenance."
Gary Krommer of Commander-Aero and I have had a discussion in the background
and I need to clarify my statement.
Let me quote Gary here: "...all turbine Commanders fall under 91.409f(3).
Rockwell created a Phase Inspection Program for all early turbines. Consists
of 11 Phases which have to be completed in a 100 hour cycle. You are not
required to comply with all the time items that you do on the 690, such as
12/15 year inspections, 5 year landing gear, ETC, ETC. Hartzell propellers
follow overhaul requirements (5 year/3000 hours). Ham. Standard (no overhaul
requirements)."
I was trying to say that the 680 series Turbo Commanders do not have 5/12/15
year inspection or overhaul requirements. Sorry if I mislead people into
thinking the 680 series Turbo Commanders didn't need maintenance!
I'll stand in the corner and be quiet now.
Thanks Keith. All the discussion is finally beginning to sink in and
I'm beginning to get a clue about what's required to maintain a
turbine. Can you clearify the phase inspection concept for me just a
bit further? You mentioned 11 phases on a 100 hour cycle. Does this
mean that the 11 "inspections" must be accomplished each 100 hours, or
are they cumulative? (ie: a phase 5 inspection occurs each 500 hours)
Are annual inspections required outside of the phase inspections?
Anyone have a short summary of what the "phases" are?
Sorry for all the questions. The wealth of knowledge represented by
the people on this list is astounding!
