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Author Topic: Jet Engine Assisted Takeoff and Mixed Propulsion Differences  (Read 2720 times)

Offline Stuka_Hunter

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Greetings

I was Googling some stuff about JATO the other day and to my surprise all results were about RATO rockets, not JATO specifically (thats why I stated ˝Jet Engine Assisted Takeoff˝in the title of this topic). I only managed to find one example of JATO being mounted on any aircraft, that being the Avro Shackleton MR.Mk.3 Phase 3. My question is: are there any other examples of JATO being used? ???

Kind regards,
Stuka_Hunter  :)
« Last Edit: August 01, 2018, 04:12:56 am by Stuka_Hunter »

Offline bob225

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Re: Jet Engine Assisted Takeoff - Examples
« Reply #1 on: July 29, 2018, 01:11:28 pm »
Locheed Neptune?
B-36 peacemaker?

Online Arjen

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Re: Jet Engine Assisted Takeoff - Examples
« Reply #2 on: July 29, 2018, 01:49:28 pm »
I am fairly sure the tail-mounted J33 in the North American Savage helped it to take off from carriers. There's JATO for you.
I may be wrong about this, but I seem to recall JATO and RATO were frequently mixed up. 'JATO bottles' - rocket packs?
« Last Edit: July 29, 2018, 01:54:31 pm by Arjen »

Offline jstar

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Re: Jet Engine Assisted Takeoff - Examples
« Reply #3 on: July 29, 2018, 02:17:50 pm »
« Last Edit: July 29, 2018, 02:25:55 pm by jstar »

Offline CJGibson

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Re: Jet Engine Assisted Takeoff - Examples
« Reply #4 on: July 29, 2018, 06:30:46 pm »
As far as I know JATO and RATO are the same thing. JATO (J refers to a jet of rocket efflux) is old terminology and became RATO when gas turbines i.e. jet engines, became the powerplant of choice in the late 1940s.

Gas turbines on piston-engined aircraft are usually referred to as auxiliary or boost engines.

Chris

Offline Stuka_Hunter

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Re: Jet Engine Assisted Takeoff - Examples
« Reply #5 on: July 30, 2018, 12:11:53 am »
Locheed Neptune?
B-36 peacemaker?
Martin P4M Mercator?

and some of these: https://en.wikipedia.org/wiki/Category:Aircraft_with_auxiliary_jet_engines


I was aware before that these aircraft have auxiliary jet engines, but none of them qualify for JATO in my opinion. That is simply because they can still be used after takeoff on Martin P4M Mercator, Lockheed Neptune, NA Savage and on the Peacemaker, primarily for increased speed over the target (I dont know about Avro Shackleton though).

Comparing that to RATO (I know there might be a slight mixup between both RATO and JATO), which stops working after takeoff, it isnt the same. However, all of the airplanes mentioned above do qualify for mixed propulsion, utilising two different types of engines on one airframe.

Does anyone have info about this one, the Fairchild C-123J. On the wingtips are J44 jet engines.


Offline Zootycoon

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Re: Jet Engine Assisted Takeoff - Examples
« Reply #6 on: July 30, 2018, 01:59:15 am »
DH Trident 3b

A rare example of jet with a take off assist jet.

Offline Jemiba

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Re: Jet Engine Assisted Takeoff - Examples
« Reply #7 on: July 30, 2018, 02:03:15 am »
Another example would be the Nord 2508 Noratlas, fitted with two Turbomeca Marboré IIE auxiliary
turbojets at the wing tips.
It takes a long time, before all mistakes are made ...

Offline PaulMM (Overscan)

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Re: Jet Engine Assisted Takeoff - Examples
« Reply #8 on: July 30, 2018, 02:08:58 am »
Yep, there was no distinction between 'jet' and 'rocket' at that time, JATO was used initially when referring to boosting piston-engined aircraft, and RATO became more popular once you were assisting a jet aircraft to take off.

A true jet engine based disposable/jettisonable "JATO" would not work as the thrust to weight ratio would be far too small especially in those early days and the cost too high. Rockets are simpler, cheaper and lighter, the only downside (high fuel consumption / low endurance) not relevant to a takeoff boost.
« Last Edit: July 30, 2018, 02:10:42 am by PaulMM (Overscan) »
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Offline jstar

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Re: Jet Engine Assisted Takeoff - Examples
« Reply #9 on: July 30, 2018, 03:40:06 am »

"Does anyone have info about this one, the Fairchild C-123J. On the wingtips are J44 jet engines."

In 1955 the prototype C-123B was fitted experimentally with two Fairchild J44 turbojet engines mounted at the wingtips to provide auxiliary power for use in an emergency. As a result ten production aircraft were modified into C-123J with turbojet engines fitted.

http://aviastar.org/air/usa/fair_provider.php

Ten C-123Bs were fitted with two Fairchild J44 turbojets, with about 4.45 kN (450 kgp / 1,000 lbf) thrust each, one mounted on each wingtip; they were also fitted with neat retractable ski landing gear, to be given the new designation of "C-123J", and used for service in Arctic regions. The US Federal Aviation Administration also used two Providers similarly fitted with Continental J69 turbojets on the wingtips, the J69 being derived from the French Turbomeca Marbore turbojet. These two machines were used in Arctic regions as well; it is not clear if they had any special designation.

http://www.airvectors.net/avboxcar.html#m4
 
« Last Edit: July 30, 2018, 03:46:05 am by jstar »

Offline charleybarley

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Re: Jet Engine Assisted Takeoff - Examples
« Reply #10 on: July 30, 2018, 09:15:24 am »
Probably in a category of its own, ie using its cruise missile armament to supplement take-off thrust, the B-52 with Hound Dogs. 2 HD J52 engines used on TO gave 15,000 lb thrust. Ref Jack Connors book. J52 was going to be cheapened as one-use only until pilots started using it to assist TO.
« Last Edit: July 30, 2018, 01:10:36 pm by charleybarley »

Offline Stuka_Hunter

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Re: Jet Engine Assisted Takeoff - Examples
« Reply #11 on: July 31, 2018, 11:47:38 am »
I would like to thank for all the answers on this topic so far.

However, one question remains: How would you by definition separate the aircraft with mixed propulsion (example: Ryan Fireball) from the airplanes with auxiliary engines (example: C-123J), or does both mean the same thing?  ???

Offline Dynoman

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Re: Jet Engine Assisted Takeoff - Examples
« Reply #12 on: July 31, 2018, 01:56:50 pm »
Stuka_Hunter, IFAIK the first aircraft in the US to fly with an auxiliary takeoff propulsion system was GALCIT's 1941 Ercoupe, which was called a JATO (Jet Assisted Take Off) despite the fact that it used six small rocket motors. In Beyond the Saga of Rocket Science by Walter Sierra, Von Karman of GALCIT thought that the term 'rocket' had the connotation of being an embryonic technology for a manned aircraft and that the acceptance of the term 'jet' would be more universal. Later the terms JATO and RATO were interchangeable. Of course today, it would probably be more accurate to use the term JATO with those aircraft using a turbine auxiliary propulsion systems and RATO with those aircraft using rocket propulsion for assisted takeoff.   
« Last Edit: July 31, 2018, 02:01:13 pm by Dynoman »

Offline CJGibson

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Re: Jet Engine Assisted Takeoff - Examples
« Reply #13 on: July 31, 2018, 06:25:35 pm »
I'd say JATO is an obsolescent term. RATO or RATOG describes the equipment better in modern literature. However, I note JATO still being used in articles about the Blue Angels Fat Albert.

Chris

Offline charleybarley

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Re: Jet Engine Assisted Takeoff - Examples
« Reply #14 on: July 31, 2018, 07:43:21 pm »
Quote
However, one question remains: How would you by definition separate the aircraft with mixed propulsion (example: Ryan Fireball) from the airplanes with auxiliary engines (example: C-123J), or does both mean the same thing?

I wouldn't try to do it by definition. I would use a few extra words so there is no ambiguity/ cause for confusion.

The following both have mixed-propulsion and the statements may not be strictly correct and could obviously be improved but are meant to illustrate the value of a few extra words over supposedly "defined" terminology, in this case mixed-propulsion.
The Fireball had a piston engine added  because the early jet engine alone was not considered suitable for operating from a carrier deck. Do we want to come up with a term for this? PATO/PAGA -prop assisted take-off and go-around?
The B36-D had jets added because the pistons alone were too slow over the target.

A further illustration of the shortcomings of definitions, ie are we all using the same?
The following statement will cause confusion and worse because your definition is different to mine.  The Skyhawk, Shackleton Mk3 and Gannet had thrust augmentation.
It's better if I say:
The thrust on the Skyhawk was insufficient to get it off the deck so it was augmented with a steam catapult.
The prop thrust of the Shackleton was insufficient for take-off so it was augmented with jet engines.
The Gannet's role was looking for submarines for which it needed one Mamba and one propeller. The prop thrust was insufficient to get it off the deck and to its patrol area quick enough so it was augmented with an extra Mamba and propeller.


« Last Edit: July 31, 2018, 08:41:17 pm by charleybarley »