Turbine DC-3s
 

Has anyone flown the turbine conversions of the DC-3 , Basler DC-3 BT-67 (PT6A-67) and the DC-3C-TP from South Africa (PT6A-65) ?

Dodson (DC-3C-TP) have some take off and landing distances on their website showing 3,600ft or 1,200m runway requirement at sea level , seems like a lot.

If they could operate out of 1,000m sea level equivalent strips I could have a few Indo operators interested.

Any comments on either aircraft from an operator or pilot's perspective would be appreciated especially getting in and out of shorter strips.

3600'/1200m was the minimum useable runway length for the standard piston DC-3, at least in UK CAA Public Transport category back in the 70's. This was straight out of the Douglas book, and happened to be the minimum accelerate/stop to 82-86kts (long time ago!), at Max AUW, ISA, sea-level. Would be very surprised if turbining has not produced better figures.

The Aero-Mod Intl. book I've got (65-ARs) shows at sea level on a 25c day, no wind or slope, about 3700 feet to make it to 35 feet weighting 24,000 pounds. Up it to 26,900 and it's around 5200-5300 feet. Accel-stop is always a lower number. Second segment is 2% gross at 26,900, I've forgotten what the turboprop requirement is.

I've now found my old piston DC-3 Manual, and I hesitate to post any more figures for the moment, as it would seem to indicate that it out-performs some turbine DC-3 conversions, about which I know very little.
Think I'll wait for someone else to post some more turbine figures first. Incidentally 12,200kgs/26,900lbs was our MLW in the 70's. 12,700kgs/28,000lbs was our MTOW. Do I take it a blanket airframe restriction was put in place at some time?

If the turoprop engine is not flat-rated, the piston DC-3 probably does have pretty good numbers up to (some) altitude (as it's supercharged).

Previously, the -3 was 25200lbs.Max (25346 with deice boots).

Most US DC-3's are now limited to 26200 (pax) or 26900(cargo) Max TO/Max Lndg by their Increased Gross Weight STC performance manual.

Some Part 137(Ag) operators would go up to 31000 or 31500 lbs for TO, like old WWII "war loads", but with a dump system for the chemical.

When I started flying them in 1980, all of ours were ex-C47s used as freighters and all had MGTO, MZF and MGL at 26,900 and V1, Vr and V2 at 84.2. If you could explain where the .2 knots came from, the oral was over.

It's not flat rated but de-rated from 1424 to about 1220. It'll pull that till 30 degrees C.

If you could explain where the .2 knots came from, the oral was over.

Conversion from MPH to KTS?

I suspect, but cannot prove, that the seeming lack of TO performance comes from the prop, which is probably optimized for a faster aircraft. If you could change out the prop gear ratio and swing a bigger prop (3 blades, like the old HSD), you might gain a worthwhile TO improvement.

Pilot DAR might have something to say on the issue.

Seems a waste to buy a turbine Dak and spend all that money and end up with the performance of ... a piston Dak.

Ok , it burns avtur not avgas but seems like an opportunity was missed to give the aircraft some decent performance gains.

You might want to try Avcanada forum. 'Kenn Borek Air' who has several of them and I heard getting more, (unconfirmed). They have many crew and management very chatty on that site I expect will happily reply to your request. The book figures and what people will tell you they do may be two different things, KBA has a reputation for getting the job done if you know what I mean.

Just be aware that Avcanda site is very heavily moderated now, and is very pro KBA I hear,(management are mods) but that shouldn't effect the information you are after.

When in South Africa a couple of years ago, I heard the unmistakable whine of a couple of RR Darts, and then noticed a passing DC-3, just departing.
So...did someone fit Darts to the 'ole bird?

BEA converted two aircraft to Darts and used them for a short while in the early fifties. They were only used for freight (with the crew on oxygen) due to being unpressurised and obviously weren't economical for paxing at comfortable lower altitudes.
I'm absolutely certain there are no Dart-powered Dakotas/DC3s in existence, flying or otherwise.

Rolls did a couple for BEA pre-Viscount to get some operating experince but they were un-converted after a couple years.

Conroy Aircraft put Darts on a Three and Super Three around 1970. They later pulled the Darts off the Three and put on PT-6s, don't know what happened to the Super Three.

I'd guess the reason the performance numbers don't change much is the power plants are staying in the 1200-1350 HP range of the recip engines. No one seems to want to do the engineering to up the power plant. What you do get is a bit more cruise speed - less frontal area - and a whole lot less maintenance.

Good start Dufo, but the conversion of what number?

Dart-powered Daks..
 

I seem to recall that the Dart-powered Dak had the blue/red/amber prop-status lights which were fitted to F27s and other types.... nightmare! bm

With a finite mass, I suspect it's got more to do with the strength of the trusses/wing spar than a missed opportunity.

Just nice to see the old girl still going. Remember visiting one on Beef Island many years ago and looking in the cockpit at the throttles and rpm levers all shiny brass - with use. An aircraft with character.

The first generation that flew them are probably all grand dads or pushing up daisies - but the aircraft are still there - that says something (not sure what, but something . . .).

Great-grand-dads, easily.

But that's not all. The mother of the last KC-135 pilot has not yet been born. :eek:

Oh, come now, they weren't that bad....:rolleyes::}

I've had a couple of years flying piston, Basler-67 and South African -65AR versions of the DC3 (and the Basler -45 demonstrator).
SA -65AR MTOW 29,000lbs, Basler -67 MTOW 28,750lb, piston MTOW 26,900lbs
IMHO the Basler is the better aircraft, as it is totally remanufactured, whereas the South African aircraft are just conversions.

Grizzly Bare. Tell us more. They can't be many people in your position.

Don't shoot me down in flames if this info is incorrect, but when I was flying (sep) in Africa, I got to know a guy who flew contract on the turbine DC3's up north. He told me they used to take about 20tons into a 400m strip and take out 15 tons out from a 500m strip. He said these were the shortest strips they operated from, seemed like a good guy is that info sounding correct.

No that is NOT sounding correct!! Given that a turbo DC-3 will have a lower APS weight due to the lighter engines, that statement is still way wide of the mark. Across seven DC-3's, our freighter config APS weights varied from 8138 to 8553kgs, (type of floor, totally stripped out or pax overhead racks left in etc etc), and if we assume the up-to-date MTOW of 12,200 kgs, this gave a useful load, after allowing for 90 mins fuel, (120 I.G.), of between 3261 and 3647 kgs.
So, 15-20 tons? Put it through the door and bust the aeroplane before it even turns a wheel, I would suggest.
Having said that, I once nearly took a max HP-7 Herald load out of Bournemouth; luckily the old girl told me in no uncertain terms that she was not going to fly like that even as we taxied out, or rather wallowed in the general direction of the holding point.
Throw all caution to the winds and yes, she will operate from 400-500 yard strips, but no accelerate/stop possibility, and an operating-speed/decision grey area as big as a battleship.
Nice guy maybe, but what grade of alcohol was he on?

No, I don't think so.

Blimey a Hercules could barely lift that much, let alone get it into a short strip (I know it CAN be done, but with bugger all fuel onboard etc etc - but not for a Dak)

Bla Bla Bla, that is exactly what the bloke told you, bla bla bla. It must have been after quite a few frosties.

TP DC-3 going to take nothing in or out of a 500m strip not even itself, and going to stop on its nose if it tries.

TECH INFO

MAXIMUM ALLOWABLE TAKE-OFF WEIGHT
13 154 kg
BASIC EMPTY WEIGHT
6 962 kg
2 CREW @ 91 kg
182 kg
EMPTY OPERATING WEIGHT
7 144 kg
MAXIMUM LOAD
6 010 kg
MAXIMUM FUEL LOAD
3 224 kg
MAXIMUM USEABLE FUEL
3 190 kg
MAXIMUM LOAD WITH MAXIMUM FUEL
2 786 kg
VFR RESERVE – 45 min @ 371 kg/hr
272 kg
BURN-OFF
408 kg/hr
TAS
170 kts
AVAILABLE EN-ROUTE FUEL – FULL TANKS EXCL RES
2 918 kg


WEIGHTS

MAXIMUM WEIGHTS (lbs./kg)Ramp Weight29,300 lbs/13290 kgMaximum Take-Off Weight29,000/13154Maximum Landing Weight28,750/13041Maximum Weight in Cargo Compartment11,790/5347.9Maximum Zero Fuel Weight26,200/11884
STANDARD AIRPLANE WEIGHTS (lbs.)Standard Empty Weight15,710/7125.9Maximum Useful Load (including ramp fuel)13,590/6164.3
CARGO SPACE Main Compartment (S.F.)287.6Lavatory Compartment (S.F.)15.0Cargo Door Size (in. wide x in. high)84 inches x 56 inches
2.13360x1.42240 Meters
SPECIFIC LOADING Wing Loading (lbs. per sqr. ft.)28.7/13.018 kilos per S.F.Power Loading (lbs. per hp)10.2/4.6266 kilos per

TAKE OFF PERFORMANCE

STALL SPEED. (CLEAN)
69 KIAS.
STALL SPEED
(GEAR + FLAPS, EXTENDED)
64 KIAS.
V1
78 KIAS.
VR
80 KIAS.
V2
86 KIAS.
T/O DIST. (TO 35 ft)
3600 ft
ACC/ STOP DIST
3220 ft
FIRST SEGMENT CLIMB
1.9% Gross Grad.
SECOND SEGMENT CLIMB
4.0% Gross Grad.
EN ROUTE CLIMB. (2000 ft AGL)
2.1% Gross Grad.


LANDING PERFORMANCE

APPROACH SPEED VREF.
84 KIAS
LANDING DIST. (50 ft OBSTACLE)
2750 ft. (NO REVERSE POWER)
APPROACH CLIMB
4.0% Gross. Grad.
BALKED LANDING CLIMB
5.2% Gross. Grad.

NOTE:TAKE OFF AND LANDING PERFORMANCE TABLES SHOWN ASSUME
WIND= 0 kts AND RUNWAY SLOPE = 0%.

I heard 'legends' of DC-3s getting in and out of 800 to 1,000m strips fully loaded but the reality seems to be 1,200 to 1,400m

Thanks for the contributions so far

The legends about "getting out" are likely true, but there are many "what ifs" to be answered.

In wartime, C-47s were often loaded far above their certified MTOW - but they had NO OEI capability. Blow a jug, and you were going to land quickly, probably not where you prefer. To do this in peacetime, in a civilized country, is criminal behavior. Ditto operating from a strip shorter than the ship's accelerate-stop requirement.

Don't confuse apples and pineapples.

Basler -67 performance from the FM, for S/L at ISA+20* (35*C).
Climb weight limit = 26,550lbs, MTOW 28,750 available at -7.5*C.
A/Go (over 35ft) for 28,750lbs = 5,600ft, A/Go for 26,550lbs = 3,750ft.
A/Stop Dist for 28,750lbs = 4,667ft, A/Stop Dist for 26,550ft = 3,750ft.
Landing Dist (over 50ft) for 28,750lbs = 3,650ft, Landing Dist for 26,550ft = 3,100ft.

Unfortunately the standard FAA FM from Basler is very "light" when it comes to fuel consumption figures, we ended up using modified Beech 1900D power/fuel flow tables (as 1900D has -67D engines and Basler has -67R engines), with no ramp weight or taxi/takeoff fuel burn published.
Typically 8000ft at ISA+20 we would achieve 180KTAS at 900lbs/hr

Empty weight of our aircraft was 16,335lbs, so typical max fuel & payload for 26,550lbs TOW was 10,215lbs (4,632kg)

South African -65AR performance from the FM, for S/L at ISA+20* (35*C).
With APR - MTOW = 29,000lbs
Climb weight limit = 28,200lbs, MTOW 29,000 available at 26*C.
A/Go (over 35ft) for 29,000lbs = 5,667ft, A/Go for 28,200lbs = 5,333ft.
A/Stop Dist for 29,000lbs = 4,333ft, A/Stop Dist for 28,200ft = 4,750ft.
Landing Dist (over 50ft) for 29,000lbs = 3,667ft, Landing Dist for 28,200ft = 3,400ft.

Without APR - MTOW = 26,900lbs
Climb weight limit = 26,1500lbs, MTOW 26,900 available at 21*C.
A/Go (over 35ft) for 26,150lbs = 4,400ft, A/Go for 26,900lbs = 4,800ft.
A/Stop Dist for 26,150lbs = 3,500ft, A/Stop Dist for 26,900lbs = 4,667ft.
Landing Dist (over 50ft) for 26,150lbs = 2,900ft, Landing Dist for 26,900ft = 3,050ft.

Again, unfortunately the standard South African FM from Wonder Air is very "light" when it comes to fuel consumption figures, we ended up using modified Beech 1900C power/fuel flow tables (as 1900C has -65 engines and these turbince DC3's have -65AR engines), with no taxi/takeoff fuel burn published.
The same as the Basler, typically 8000ft at ISA+20 we would achieve 180KTAS at 900lbs/hr

Ramp Wt = 29,300lbs.
Empty weight of our aircraft was 14,845lbs, so typical max fuel & payload for 28,200lbs TOW was 13,355lbs (6,056kg)

I spoke with the operator last week and they'll be looking at a Caribou next year , the turbine DC-3 won't cut the strip lengths they have to operate into , the DHC-4 does everything they want with a good safety margin except it burns avgas and the R-2000 seems unable to make TBO (other operators I spoke to said figure on 800hrs for an engine). Should be fun for the pilots.

DHC-5 would be much better....if you can find one.

Agreed, but if you're operating in sand/dust, you'd better find someone who's invented an inlet particle separator. I've seen compressors badly eroded after 1000 hrs.

Look at the Penturbo.com -67 DHC-4 re-engine.

WEIGHTS
Design Take-off Weight
Design Landing Weight
Maximum Zero Fuel Weight
Maximum Payload
Maximum Fuel
(Internal Tanks)


The following is a summary of the performance data that applies under ISA conditions at the design gross weight of 28,500 lbs. Takeoff and landing distances are given at sea level, zero wind, and from a dry level surface.

TAKE-OFF AND LANDING: SHORT FIELD TECHNIQUE (STOL)
http://www.penturbo.com/tcp4_files/image004.gifAircraft Operating Data – PART 8 Charts
http://www.penturbo.com/tcp4_files/image005.gif


Take-off (flaps 25º, both engines at T.O. power)


Ground Run

Total distance to clear 50-ft. obstacle

Landing (Flaps 40º)

Ground Run

Total distance from 50-ft. obstacle






TAKE-OFF AND LANDING: AIRLINE TECHNIQUE (FAR 25)
Take-off (flaps 7º engines at T.O. power)
Ground Run
Total distance to 35-ft obstacle
Take-off (Flaps 7º)
One engine inop. at V1 to 35-ft obstacle
Landing (Flaps 30º)
Ground Run
Total Distance from 35-ft. obstacle