Hot Caravan Is it about time ?

[ZEEBEE]

From AvWeb

RE-ENGINED CARAVAN ATTRACTING ATTENTION
The Super Van 900, a Cessna Caravan with a 900-horsepower Garrett engine, was granted a supplementary type certificate (STC) by the FAA recently, and interest is strong in the souped-up Caravan. IFR magazine editor and AVweb contributor Jeff Van West spoke with Texas Turbines CEO Bobby Bishop about how more ponies help this workhorse.

This should make the Northern operators a little more happy...even if they do go deaf.

[Air Ace]

What on Earth would one use that for?

Has the Max TO Weight and payload been increased?

[The Green Goblin]

T least the chances of an engine failure have dramatically reduced with the addition of the Garrett :)

I wonder if it will get CAWI too?

[j3pipercub]

HA!

A van with CAWI, I think I'm in love :}

j3

[ZEEBEE]

Green Goblin wrote

T least the chances of an engine failure have dramatically reduced with the addition of the Garrett

Do you really think so ?

I would have thought that the PT was pretty hard to beat on that one...unless you run out of fuel, but I reckon the Garrett at 900SHP would be the same as the PT6 at 650.

[startingout]

Too bad there is no "How do the passengers deal with the extra noise"in the FAQ section.... looks like good fun that thing. Sitting up front pax seat of a metro isnt the best experience noise wise, this may be better though being behind the props.

linky here: TEXAS TURBINE CONVERSIONS, INC. - Caravan Conversion - (http://www.texasturbines.com/caravan/ttci_faq_c.htm)

SO:ok:

[Air Ace]

No mention of any increase in max TO weight - but the empty weight increases by 100 pounds.

I wonder if the Garrett engine has demonstrated the 1 in 100,000 engine failure rate required for IFR? And I can't see Cessna supporting the aircraft for ASEPA approval........

[RadioSaigon]

'scuse my ignorance... but CAWI?

It's a helluva job keeping up with all these acronyms and abbreviations!!!

[Pilotette]

CAWI...Continuous Alcohol Water Injection
Water/methanol mainly used in hot/high conditions...Water increases density and the metho assists in the effeciency of the burn.
Basically gives you more bang for your buck (boost)...others will know more :ok: Pilotette

[j3pipercub]

It's ok that you had NFI, aviation is filled with all those wonderful accronyms

Continuous Alcohol Water Injection

At least I think so...

j3

[RadioSaigon]

Cheers Pilotette and J3! Onto it now ;)

Last time I heard of water-meth, it was in the old RR Darts! Didn't know it was still in use in current engines... and continuous? Surely that would be a fearsome volume/weight to be carting around?

[The Green Goblin]

Still used on the mighty metro, enough for about two takeoffs ;) (or 3 if you worked at Macair)

[remoak]

Not to be too picky, but...

Water/methanol mainly used in hot/high conditions...Water increases density and the metho assists in the effeciency of the burn

The water doesn't increase the density (of the air), it actually decreases it as it displaces air with water. However what it does do is cool the air, thus increasing density. The methanol doesn't increase combustion efficiency, it just burns (and very nicely too).

We used to use it for most takeoffs in the F27. Works well but you go through more water meth per takeoff than you do fuel.

[j3pipercub]

Anyway,

Garrett van, haven't looked all that closely at the specs. Is the inertial separator still part of the system? Can't really see much of a use of the van in the backlots if you've got a straight garrett in the front without some form of FOD protection.

j3

[The Green Goblin]

Quote:
T least the chances of an engine failure have dramatically reduced with the addition of the Garrett
Do you really think so ?

A Garrett is a much stronger little turbine than a PT6, the only downfall is they are noisy and they loose performance (and cooling power from the bleeds) in warmer environments. I'd still rather have a Garrett strapped to my wing!

[Air Ace]

"A Garrett is a much stronger little turbine than a PT6..."

Er ... where did that little gem come from? :confused:

I don't recall seeing too many Garrett turbines installed in GA bush work horses such as the Twin Otter, Bandeirante, Beech King Air range of models, Rheims Cessna 406, Cessna Conquest I and the Cessna Caravan. Indeed, Pilatus removed the Garrett engine option from the Porter due to it's lack of reliability and non modular maintenance design. One of the principal failures of the Shorts Sky Van was it's Garrett engine, which resulted in Shorts using PT6's in the SD3-30 and SD3-60.

You may be biased to Garrett, as I am biased to PT6s, but let us stick to demonstrated and proven facts, eh?

[j3pipercub]

Just wading in waist deep into this one but, I thought Centrifugal Compressors were quite a bit stronger than axials. Will happily stand corrected on that one though.

Furthermore the PT-6's on low wing a/c all have ice-vains/inertial separators. Garrett's answer to this is flipping the engine on it's back :hmm:

I fly Garretts, but I wish they were PT6's:{:{ I miss the PT-6

j3

[The Green Goblin]

Okay Air Ace,

You have your opinion, but you may find the Cessna Conquest are Garretts :)

If you are ever bored check out the performance figures of a metro vs a 1900 or a Conquest vs a King Air!!

You will be very surprised ;)

[The Green Goblin]

I fly Garretts, but I wish they were PT6's

j3

Wash your mouth out with soap!!

[j3pipercub]

What?? Maybe I'm just in love with King-airs :ok:

I'm almost positive that the Conq 1's had PT6's in them GG, you might have been defeated on that one.

But I will give the Garrett something. Fuel burn. Absolutely amazing. 1000shp at 350lbs/hr @ A100 vs PT6-114A 675shp 300 lbs/hr @ A100.

And yeah, the water meth is pretty cool.

j3

[Pilotette]

J3's right about the Conquest I's having PT6's but the Conquest II's all have Garretts...I'm a Garrett fan too :ok: (even though I do also like the King-air!)

[The Green Goblin]

The conquest 1 was a turboprop version of the 425 - not a real conquest as we know it, with only 8 seats. I've never seen one in the flesh, the only PT6 version of the conqy that I have seen is the F406 and its closer to the 404 than the 441 :)

Its not just the fuel flow though that makes the 331 a better performer than the PT6, its also TAS and as a result of fuel flow, range.

[Unhinged]

"the only downfall is they are noisy"

Now *that's* an understatement - Not so bad inside the aircraft, but ear-splitting when they taxi past !!!

[nightmode]

Anyone who's flown a Metro will know about the "Metro Salute" when taxiing in... People standing around with fingers in both ears till you shutdown :E. Guess the van with garrets will do the same!.. or... people standing around with one finger in one ear?????:}

[romeocharlie]

The Model 441 Conquest was the first to be developed, it was designed concurrently with the piston engined 404 Titan in the mid 1970s. Development was announced in November 1974, and the first flight occurred in August 1976. First customer deliveries were from September 1977. The 441 shares a common fuselage with the Titan, but has a longer span (bonded and wet) wing, a pressurised fuselage, and most significantly, Garrett TPE331 turboprop engines. A PT6A powered 441, designated the 435, flew during 1986, but it did not enter production.
The 425 Corsair meanwhile was introduced to the Cessna model lineup from 1980. Based on the Model 421 Golden Eagle, it differs from its donor aircraft in having turboprop engines (in this case PT6As). Design work on the Corsair began in 1977, first flight was on September 12 1978 and first production deliveries took place in November 1980.
From 1983 Cessna renamed the Corsair the Conquest I, while the Conquest became the Conquest II. Production of both ceased in 1986.
The French built Reims Cessna F406 Caravan II meanwhile is something of a hybrid, incorporating 373kW (500shp) PT6A112s, the unpressurised fuselage of the Titan and the Conquest II's wings. First delivered in late 1984, the Caravan II is the only Cessna turboprop twin currently in production.

Copyright Airliners.net, some information Copyright Aerospace Publications

[remoak]

The Garrett (TPE331) is a far more responsive and fuel-efficient engine, and normally has a longer TBO than the PT6 (commonly 5400 hours for the TPE331 vs 3600 for the PT6). Garretts are more sensitive to sloppy engineering, harder to fix in the field which is why bush applications commonly use the PT6.

Sensible design - air goes in the front and out the back - no inertial separators required! Not back-asswards like the PT6. One of the reasons that the Garrett is more efficient.

I thought Centrifugal Compressors were quite a bit stronger than axials.

Garretts use centrifugal compressors too (two of them).

On the reliability front, Garretts are very reliable indeed, which is why the Americans selected it to engine the Predator B drone. That thing loiters forever.

Have flown thousands of hours on both PT6s and Garretts. Never had a Garrett fail, but I've had two PT6s shed their innards on me. The PT6 is a good GA engine, but the Garrett is better in airline ops.

[Air Ace]

Hmmm. I'm sure I said Cessna Conquest I?? :confused:

It was good enough to serve the RFDS in West Australia for many years.

And few operators are on the base PT6 TBO around 3,600 hours. Most serious operators would be on either extended TBO or On Condition. I've known a PT6A-34 On Condition to run in excess of 10,000 hours before being overhauled. Equally, the Garrett can be approved for extended TBOs.

The Conquest II had a Garrett -8, which most operators replaced as soon as STC's for the -10 became available.

But it is "horses for courses" and I accept the Metro was a great accountant's machine - except perhaps the Metro I with -3's and the Merlin ... enough said! :{

But we digress and back to the thread topic. I can not think of any Garrett single engine commercial aircraft installation (except the short lived Pilatus Porter), which leads me to suspect that unless someone has lashings of $'s, a Garrett powered Cessna 208 Caravan will probably remain a day VHF aircraft.

[Grogmonster]

Hey Green Goblin you are one of the greatest wind up merchants I have seen on prune. "Metro performance surprising v's a Kingair ", very funny!!! If it weren't for the curvature of the earth a metro would never get airborne. I love your sense of humour.

Groggy.

[The Green Goblin]

Hey Green Goblin you are one of the greatest wind up merchants I have seen on prune. "Metro performance surprising v's a Kingair ", very funny!!! If it weren't for the curvature of the earth a metro would never get airborne. I love your sense of humour.

Groggy.

I may be a windup merchant on the odd :} occasion but I did compare a Metro to a 1900 not a King Air. If you want to compare it to a King Air however lets just say 3 things, it uses less fuel than a King Air, is faster, has a greater range and can carry twice the payload :)

Only thing a King Air trumps a metro is land and take off distance which I must admit even a 737 will out do a metro :ugh: