Zyzygie’s Mumbles and Rambles (1 Viewer)

[FLYBOYJ]

When the engines start, you have to watch the pyrometers (exhaust temp) stabilize and then bring the engine RPMs up to level.

When that occurs, you're only looking at about 30 seconds. After that you're good to go, unlike a recip where you may have to wait several minutes for oil temps and pressures to come up before you could even taxi.

Great flick!

 

[fastmongrel]

When that occurs, you're only looking at about 30 seconds. After that you're good to go, unlike a recip where you may have to wait several minutes for oil temps and pressures to come up before you could even taxi.

Great flick!

How did the Spitfires and Hurricanes scramble so quickly during the BoB if the engine needed to warm up first. Were the engines kept warm by being fired up regulary.

 

[kool kitty89]

In many if not most turbine engines, there is little "warm-up" time needed unlike a recip. Cool down during shut down - different story.

This is from Zeno - the POH developed by the AAF for captured Me 262 operation. Although there is a paragraph about "warm up" and ground test, there is no specific warm up parameter, the only requirement was ensuring the exhaust temp didn't exceed 650 C.

For fuel conservation


When the engines start, you have to watch the pyrometers (exhaust temp) stabilize and then bring the engine RPMs up to level.

While the Rydell expedited the process as opposed to an electronic start, it still saved a great deal of fuel starting the engines on the flightline and then on to a direct T/O instead of startup back on the ramp and taxiing into the que.

Additionally, I'd imagine the slow spool up and down times made towing faster and more reliable in a number of cases, not to mention less wear on the tires and wheel breaks.

I also recall Jumo 004B start-up procedure including use of high volatility gasoline for initial start and warm-up, followed by dilution with kerosene/diesel (J2) as the combustion chambers warmed up.

Given that several other early turbojets (including the Nene and Derwent V post-war) had dedicated engine-start fuel lines independent of the main fuel lines, this sort of operation doesn't seem that unusual. (I'm not sure if the Derwent/Nene used special fuel or just pre-heated kerosene or something else, but the dedicated starter-fuel line seems indicative of something special going on)

Heinkel/Ohain's jet engines used hydrogen for their initial warm-up to avoid fouling of the vaporizer jets. (later versions during HeS 8 development may have switched to atomized burners allowing cold start on liquid fuel, but I suspect a more likely solution would have been adapting some more convenient volatile, smokeless liquid fuel like methanol -Ohain's burners operated like that of a blow lamp, requiring preheating and ending up a horrible sooty mess if gasoline/kerosene was used for this)

 

[Zyzygie]

Additionally, I'd imagine the slow spool up and down times made towing faster and more reliable in a number of cases, not to mention less wear on the tires and wheel breaks.

I also recall Jumo 004B start-up procedure including use of high volatility gasoline for initial start and warm-up, followed by dilution with kerosene/diesel (J2) as the combustion chambers warmed up.

Given that several other early turbojets (including the Nene and Derwent V post-war) had dedicated engine-start fuel lines independent of the main fuel lines, this sort of operation doesn't seem that unusual. (I'm not sure if the Derwent/Nene used special fuel or just pre-heated kerosene or something else, but the dedicated starter-fuel line seems indicative of something special going on)

Heinkel/Ohain's jet engines used hydrogen for their initial warm-up to avoid fouling of the vaporizer jets. (later versions during HeS 8 development may have switched to atomized burners allowing cold start on liquid fuel, but I suspect a more likely solution would have been adapting some more convenient volatile, smokeless liquid fuel like methanol -Ohain's burners operated like that of a blow lamp, requiring preheating and ending up a horrible sooty mess if gasoline/kerosene was used for this)

The JUMO had a two-stroke starter:

"...Riedel studied mechanical engineering and worked in the 1930s, first with Ardie and then at Victoria. During the Second World War, he developed a starter engine ("Riedel starter") for the first German jet engines. The starter system, which consisted of a Riedel 10 hp (7.5 kW) two-strokeflat engine hidden in the intake, essentially functioned as a pioneering example of an auxiliary power unit (APU) for starting a jet engine. A hole in the extreme nose of the centrebody contained a manual pull-handle which started the piston engine, which in turn rotated the compressor. Two small petrol tanks were fitted in the annular intake.[1] The engine was considered an extreme short stroke (bore / stroke: 70 mm / 35 mm = 2:1) design so it could fit in the hub of the turbine compressor. For reduction it had an integrated planetary gear. It was produced in Victoria in Nuremberg and served as a starter for the operational German Junkers Jumo 004 and BMW 003 jet engines, placed on the centreline of each of these..."
Norbert Riedel - Wikipedia​

Does this mean that they had to have three different fuel systems? Not likely.
I think the gasoline requirement was probably only for the two-stroke starter

The Meteor of course used an electric starter.

 

[Denniss]

Yes, three types of fuel were carried although very limited amount of the starter fuels
Riedel engine used A3 fuel (3 liter pe engine) - AFAIR 82 Oktan, standard low-grade AV fuel also used by Fi 156, Fw 189
Jet engine starter fuel was B4 (17 liter per engine) - 87 Oktan, standard AV fuel, used by most Bf 109
Per manual tanks were located near or within the jet engines, starter fuel sufficient for ~4 start attempts; starter fuel was just for start/ignition but not for warming-up

 

[Zyzygie]

Yes, three types of fuel were carried although very limited amount of the starter fuels
Riedel engine used A3 fuel (3 liter pe engine) - AFAIR 82 Oktan, standard low-grade AV fuel also used by Fi 156, Fw 189
Jet engine starter fuel was B4 (17 liter per engine) - 87 Oktan, standard AV fuel, used by most Bf 109
Per manual tanks were located near or within the jet engines, starter fuel sufficient for ~4 start attempts; starter fuel was just for start/ignition but not for warming-up

No wonder then that the Luftwaffe had so much hassle getting more than about 30 to 40 Me 262s into the air on any given day. They only had to have a shortage of any ONE of the three fuels to rule it out.
As General Omar Bradley famously said: "Amateurs talk strategy. Professionals talk logistics."

 

[lapin-red]

I could agree with that!

WRONG

Both were bomber interdiction straight line fighters. Very fast but turning circles were awful so a dogfight would have been virtually impossible - which is why they never happened, plus of course the Meteor was banned from flying over mainland Europe until the war was virtually over. What a stupid question.

 

[DerAdlerIstGelandet]

WRONG

Both were bomber interdiction straight line fighters. Very fast but turning circles were awful so a dogfight would have been virtually impossible - which is why they never happened, plus of course the Meteor was banned from flying over mainland Europe until the war was virtually over. What a stupid question.

What a stupid answer...

 

[fastmongrel]

WRONG

Both were bomber interdiction straight line fighters. Very fast but turning circles were awful so a dogfight would have been virtually impossible - which is why they never happened, plus of course the Meteor was banned from flying over mainland Europe until the war was virtually over. What a stupid question.

Wow thats a good way to start what will probably be a very short stay on this forum.

 

[Shortround6]

And a bit lacking in fact/s

Granted a Meteor might not be able to hold a circle for very long but the early Meteors had a big wing (374sq ft) and rather low wing loading (35-36lbs/sq ft at full gross). The poor thrust means that as speed bleeds off in a turn it is harder to recover, (accelerate once the turn is loosened or stopped) so a tight turn may not be a good tactic.
The 262 had a wing about 2/3rds the size and went about 1000lbs more at take-off. Both planes burned fuel at a horrendous rate compared to piston engine planes so weight at point of engagement would be significantly less but the Meteor should always have an advantage in turn (even if not roll which was poor on the early Meteors))

 

[stona]

Someone needs to look up the meaning of the word 'hypothetical'. Actually don't bother, I'll save you the time and provide you with one.

"Imagined or suggested but not necessarily real or true"

Everyone here knows that the two never actually met, nor were they likely to. It's not the point.

Cheers

Steve

 

[FLYBOYJ]

WRONG

Both were bomber interdiction straight line fighters. Very fast but turning circles were awful so a dogfight would have been virtually impossible - which is why they never happened, plus of course the Meteor was banned from flying over mainland Europe until the war was virtually over. What a stupid question.

An arm chair aviator! It's amazing that you even know how to respond considering your single digit IQ.

 

[BiffF15]

And a bit lacking in fact/s

Granted a Meteor might not be able to hold a circle for very long but the early Meteors had a big wing (374sq ft) and rather low wing loading (35-36lbs/sq ft at full gross). The poor thrust means that as speed bleeds off in a turn it is harder to recover, (accelerate once the turn is loosened or stopped) so a tight turn may not be a good tactic.
The 262 had a wing about 2/3rds the size and went about 1000lbs more at take-off. Both planes burned fuel at a horrendous rate compared to piston engine planes so weight at point of engagement would be significantly less but the Meteor should always have an advantage in turn (even if not roll which was poor on the early Meteors))

SR6,
Great chart! I wonder how much difference there really is? I doubt the "steps" in size were as even as depicted.
Cheers,
Biff

 

[pbehn]

SR6,
Great chart! I wonder how much difference there really is? I doubt the "steps" in size were as even as depicted.
Cheers,
Biff

If the diagram is to scale then it seems the Spitfire can out turn my car at speeds over 40 MPH

 

[Magnon]

If the diagram is to scale then it seems the Spitfire can out turn my car at speeds over 40 MPH

The diagram is OK, but I don't know about whether it would be wise to dogfight with a Spitfire...
The Meteor could theoretically out-turn a Tempest, but the Tempest roll rate was much better, so it could quickly evade the Meteor.

 

[Zyzygie]

"...The first operational unit, Kommando Nowotny, led by 258-kill air ace Walter Nowotny, had high attrition rates and never resolved the Me 262's teething troubles. Nowotny was killed in a Nov. 7, 1944 action while engaging American B-24 Liberators. A new unit under Galland fared better, but the Me 262 was difficult to handle by even the most experienced pilots..."

"...Galland said that persistent allied attacks on Axis fuel supplies also hindered Me 262 operations. Toward the end of the war, Me 262s were often towed to the end of the runway by draft horses in order to conserve fuel. In addition, many airframes sat idle waiting for engines that never arrived..."

The Messerschmitt Me 262 Jet Fighter | Defense Media Network​

 

[FLYBOYJ]

A new unit under Galland fared better, but the Me 262 was difficult to handle by even the most experienced pilots...

I'll call 100% BS on that statement as well as the article. Robert Dorr was a long time aviation author and had many books published under Osprey (par for the course). Although he had a long and distinguished career in the US military, as a diplomat and as a writer, I don't think he was a rated pilot and doesn't provide any reference to back up that statement.

This is from Zeno's site, "Summary of debriefing German pilot Hans Fey on operational performance & late
war deployment of the Me 262 jet fighter."

From the document:

"Fay says that this aircraft is easier to fly than the latest types of Fw 190 or Me 109- In fact, he feels any Me 109 pilot is qualified to fly the Me 262 after one hour's instruction."

http://www.zenoswarbirdvideos.com/Images/Me262/ME262PILOTDEBRIEF.pdf

"After Brown took off, he thought the airplane was easy—a pleasure, even—to fly: The controls were responsive, there were no vibrations and compared to a piston-engine fighter it whispered."

Lt. Roy Brown ATI USAAF, 1944

Watson's Whizzers - Saving the Me-262 | HistoryNet

And a quote from another Brown;

"After his flight, Eric had the highest praise for the 262, the world's first operational jet fighter, calling it, "the most formidable combat aircraft to evolve in World War II."

Jörg "Czyp" Czypionka on Eric Brown's evaluation of the Me 262.

Jorg Czypionka

Eric Brown's own words (starts at 4:00)


View: https://www.youtube.com/watch?v=zhVp0dvwr68


There were some flight test reports that were critical of the Me 262, while not perfect by any means, I think some of these reports were agenda driven IMO. Form your own opinions but consider your sources, especially those who actually FLEW the aircraft!

 

[pbehn]

I thought the only real problem with the 262 was engine life, this isnt a problem of aircraft design or even the engine design just a shortage of very exotic metals. Some pilots were much better than others at prolonging engine life (I read somewhere on this forum). Hardly a surprise, it was the first jet to go into combat service so everyone was learning.

I am sure the first meteor pilots had the same experience learning rapidly from hard lessons what the do's and don'ts are certainly the F80 had its problems but went on to be produced in large numbers

 

[GrauGeist]

There is the occasional mention of a team draft horses being used to bring up the jets from the ramp to the line, but it was the Kettenkrad that was most often used in this role and not only for the Me262, but the Ar234 as well.

 

[pbehn]

I would have thought towing the early jets out to the end of the runway was a great idea even if you were awash with fuel, the fuel on board the aircraft was limited and the engines burned it at a high rate.