Diesel or avgas in a turbine engine
 

I've heard that its ok to run a Kingair's turbines on avgas or diesel even, for a limited time.

Just wondering if anyone could substantiate this? Or explain what the consequences would be?

But why can't you run a piston engine with Jet A1?

What about using diesel or avgas for a Cessna Caravan, or any other turbine for that matter?

Thanks.

Problem with Avgas use for a turbine is the lubrication of the usual squash plate high pressure fuel pumps.

Add some lubricity for emergency use or the pump/s may/will fail.

Then there is somewhat less energy in Avgas so you will burn a bit more to get the same result.

Someone who knows more than this may be able to come up with some numbers.

Operation with other fuels is not recommended, but operation with AVGAS for most Pratt & Whitney engines (Kingair PT6A-41,42) is acceptable in extenuating circumstances. Usually limited to a maximum combined total of 150hours in a single engine overhaul period.

Can't remember the SB # for the -41, 42 but for the -27, -28 etc check P&WC SB1244(Approved listing of fuels etc). The Caravan -114 will be similar. For the PW120 see the MM 72-00-00 4.E Table 13 for acceptable fuels, 4.F Table 14 for acceptable fuels restricted use, & 4.G Alternate emergency fuels (AVGAS)

In the end AVGAS has a different SG, & calorific value, & requires a greater temperature change to produce the same power as the recommended fuels. See higher ITT - increased hot end thermal distress.... sorry more $ per hour.

TT

You most certainly can run a piston engine (diesel) on Jet A1. The only problem here is you will significantly shorten the life of the fuel pump/injector units as Jet A1 has a about 50% of the luricity of diesel. Fuel consumption will be slightly higher due to a slightly less calorific value.

Winter diesel as used in cold climates such as Canada is typically upto 25% Jet A1. You can always add a seperate lube additive (2380 is a good one). In fact the US military use a single fuel policy which is JP8, essentially Jet A1 with 3 additives. They use this in aircraft and all "diesel" ground equipment.

Used to work for an ag operator who had a contractor running his Airtractor with a PT6-34AG on diesel. The first time I started it, it scared the hell out of and the rest of the airport. The smoke during light off was incredible.
Can't recall the exact figures but know it took a couple of hundred Hrs off the TBO and HSI's.
There is S.G. adjustment on top of the FCU to cater for diff fuels. Never have that aircraft long enough to see what the HSI was like and never heard.

The Mk III (Phase 3)Shackleton used to run AVGAS through a couple of Vipers under the outboard engines for increased take-off performance. The thermal distress meant they were binned after about 150hrs?? (which was a fair number of take-offs....)

avgas in turbines
 

Your avgas was likely a highly leaded fuel (pre 100LL), right?
The problem here was lead contamination of the metallurgy of the turbine blades & nozzles, I believe. C-123K's similarly had J85's in pods outboard of the R-2800's. KC-97L's and B-36 production models also had J47's in outboard pods, and all had the same problem.

I should think 100LL alleviates that problem, but perhaps not completely.