Early T33 ,engine starting

[helinut]

I heard that the early T33, with theJ33 engine where started on aviation gasoline,then once running switched over to jet fuel,is this right?

[A26 Special K]

Since the T-33 first flew in 1948 and JP-4 wasn’t developed until 1951, there might be a grain of truth in this story. JP-1 was a pure kerosene jet fuel developed in 1944. JP-4 was a kerosene-gasoline blend that was highly volatile but was needed to allow afterburners to ignite in the early engines or to get an engine restart at higher altitudes. It was retired in the mid 90’s for a less volatile JP-8. Other chemicals like hydrazine are used to initiate starts in later engines. Our T-33 starts and runs fine on Commercial grade Jet A with Prist. Just have to watch for coking build up in the burner cans each year during inspection. If we had access to JP-8, it would reduce the coking. That said, can anybody answer the question for certain?

[Saville]

Since the T-33 first flew in 1948 and JP-4 wasn’t developed until 1951, there might be a grain of truth in this story. JP-1 was a pure kerosene jet fuel developed in 1944. JP-4 was a kerosene-gasoline blend that was highly volatile but was needed to allow afterburners to ignite in the early engines or to get an engine restart at higher altitudes. It was retired in the mid 90’s for a less volatile JP-8. Other chemicals like hydrazine are used to initiate starts in later engines. Our T-33 starts and runs fine on Commercial grade Jet A with Prist. Just have to watch for coking build up in the burner cans each year during inspection. If we had access to JP-8, it would reduce the coking. That said, can anybody answer the question for certain?

How do you get the spinning started? Cartridge? Some sort of on-board motor to start spinning things?

Or some other way?

[A26 Special K]

Electric starter motor powered by battery or ground power unit got it spinning. Fuel and ignition come on about 8% rpm to finish the spool up.

[marine air]

Don’t think the T-33 used gasoline for starting. My Stearman/ SuperCub instructor was an early jet instructor and flew all the early jets, some in combat. I do remember him saying the P-80A had a fuel spicket valve that when it was time to introduce fuel during rotation you would rotate the vale much like turning on a home garden hose.
The first jet designs like the Caproni has gasoline powered engines that turned the compressor section. Not a jet , by today’s definition. Also, most all turbine engines will run fine on aviation gasoline. The hand book will have limitations of say, 100 hours of a gas use per engine overhaul life and an altitude restriction say, 20,000.

[marine air]

Don’t think the T-33 used gasoline for starting. My Stearman/ SuperCub instructor was an early jet instructor and flew all the early jets, some in combat. I do remember him saying the P-80A had a fuel spicket valve that when it was time to introduce fuel during rotation you would rotate the vale much like turning on a home garden hose.
The first jet designs like the Caproni has gasoline powered engines that turned the compressor section. Not a jet , by today’s definition. Also, most all turbine engines will run fine on aviation gasoline. The hand book will have limitations of say, 100 hours of a gas use per engine overhaul life and an altitude restriction say, 20,000. Will also have engine temp limits for operation.

[Joe Scheil]

As far as Ihave read, In the days before “Jet A” or Jet B...there was only kerosene and aviation fuels of varying octane levels. The early P-80 and even T-33 books say that you can run the plane on the lowest octane aviation fuels, but that is is harder to avoid over temping the engine. That said, the Kerosene that they did have was “cut” with as much as 50 percent of the lowest octane available fuel to make it better for the engines in some way. I would think that at the time they had 80 octane and 100 octane fuels available in quantity, as well as other blends of aviation fuels all the way up to 200/300 octane Methyl Triptane. It is important to remember that they did not have 100LL. I would believe the new USAF and engine manufacturers were experimenting over that time creating what became JP-4 which was finally standardized in 1951. This is essentially a 50/50 mix.

JP-1 was pure Kerosene, and was essentially what was specified in 1945. However it was unsuitable for a variety of military reasons.

Jet A in use today in vintage Jets, it’s not perfect.

Jet B is what we should be using, and it is very similar to JP-4. Its though to get at FBO’s today if not impossible. It is 30% Kerosene and 70% gasoline. I don’t know exactly what gasoline they specify but it’s not todays’ car gas.

[phixer]

Maybe someone can verify but didn't the F3D skynight use avgas. The story I remember was when the marines would fly into airforce bases they would sometimes get an argument about refueling them.

[WIXerGreg]

The J-47's on the B-36 and KC-97L burned avgas.

[JohnB]

The J-47's on the B-36 and KC-97L burned avgas.

Weren't they "detuned" to do so?

[WIXerGreg]

That's very possible, and something I couldn't answer without researching it myself. I'll do some digging on that when I get time.

[JohnB]

I've read they were modified to use avgas. In what way I don't know. I'd be interested to learn.
Considering the last of the KC-97Ls weren't all that long ago (I remember seeing them when transiting SLC), I'm sure someone knows.

It's a safe bet the J-47s in F-86s didn't burn avgas.

[Dan K]

Maybe someone can verify but didn't the F3D skynight use avgas. The story I remember was when the marines would fly into airforce bases they would sometimes get an argument about refueling them.

Curiosity led me to a pilot's handbook for the F3D-2.

http://www.avialogs.com/index.php/aircr ... craft.html


Instructions for fuel type are as follows:

FUEL: The cheapest, most readily available grade of MIL-F-5572

I do believe that describes 80/87 octane avgas.



AND THEN...

I stumbled onto the following link (After reading it, I feel like a military jet fuel historical expert):

https://apps.dtic.mil/dtic/tr/fulltext/u2/a186752.pdf

Some of the author's anecdotal text is quite entertaining (e.g. Captain Charles Hudson's private analysis of the "LF-1" fuel used for U-2 test & development).

[marine air]

A few years ago we flew a family up to Omaha to Offutt to the museum up there to see the B-36. The family patriarch had been a B-36 crew chief and we got to tour the aircraft.
He said the J-47’s were typically started just before and used during takeoff and climb. They received a gas from the main fuel tanks and they only used a gas.
This makes sense as think of how much more complex it would be to have dissimilar engines, fuels, fuel systems, etc. if you were running low on one side and wanted to move the jet fuel from one outboard wing tank to another it would be a complex and difficult. It only makes sense to only have one type of fuel in the wing.
A gas shortens the life of jet engines but it is a satisfactory option when needed.

[JohnB]

I would imagine the J85s in C-119Ks and C-123Ks and J34s in P2V-7s also used avgas.