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hello all.....first i dont own any mack truck BUT i am the owner of a brand new garrett turbocharger model TV61, it is supposed to sit on an mack endt 673 engine, i bought this turbo with the intention to build a turbojet engine and that is my big project in life but i got a bit interested in what kind of truck this turbo would have been used......any info appreciated...best regards/stephan

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Welcome to the forums! Turbo jet engines are way cool! Keep us posted!! :D

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here are some photo of special machined combustor plenum parts.../stephan

Welcome to the forums! Turbo jet engines are way cool! Keep us posted!! :D

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Nice! I've always been fascinated by miniature engines, but never had the pocketbook o support the hobby!

Some of these guys might be jealous because they might want that turbo for their 673!!

LOL

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Nice! I've always been fascinated by miniature engines, but never had the pocketbook o support the hobby!

Some of these guys might be jealous because they might want that turbo for their 673!!

LOL

hmmm...maybe possible....Barry....do you have any idea from, what mack model this turbo fits?..best regards/stephan

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My guess would be an R-Model, but it could be any number of models...

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My guess would be an R-Model, but it could be any number of models...

hello Barry!

thanks for your help, i have found myself from the net, info here and there that the engine is also called thermodyne and that it was also used in the B61 model......that means that this turbo is a brand new turbo from the fifties sometime, i think it must be qite rare turbo in such condition, it is not a rebuilt one BUT brand new never used....would be nice to know its story how it could not be used for so many years.....thanks for your help Barry....i have even got interested in those old MACKs now...especially those B and R models....best regards/stephan

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hello Barry!

thanks for your help, i have found myself from the net, info here and there that the engine is also called thermodyne and that it was also used in the B61 model......that means that this turbo is a brand new turbo from the fifties sometime, i think it must be qite rare turbo in such condition, it is not a rebuilt one BUT brand new never used....would be nice to know its story how it could not be used for so many years.....thanks for your help Barry....i have even got interested in those old MACKs now...especially those B and R models....best regards/stephan

That exhaust, and intake flange type or setup is much newer than the B, or early R model vintage. I would make an educated guess to a 237 Mack engine, about 1971-82 vintage. Not rare by any means. The .55 A/R is nothing special, and quite small for any appreciable power, (at high rpm), but great for low end grunt such as the "Maxidyne" series engines produced. This is part of the reason for the high torque rise of these engines.

I have two just like it from 1972, and 1975 R models w/237's originally. I certainly don't mean to berate your item, just don't want you to be mislead. If you are going to make a turbin engine out of it, I would get closer to a 1 A/R on the compressor side or you will too restricted for good thrust/power output; The restriction at turbin rpm is too great.

Rob

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That exhaust, and intake flange type or setup is much newer than the B, or early R model vintage. I would make an educated guess to a 237 Mack engine, about 1971-82 vintage. Not rare by any means. The .55 A/R is nothing special, and quite small for any appreciable power, (at high rpm), but great for low end grunt such as the "Maxidyne" series engines produced. This is part of the reason for the high torque rise of these engines.

I have two just like it from 1972, and 1975 R models w/237's originally. I certainly don't mean to berate your item, just don't want you to be mislead. If you are going to make a turbin engine out of it, I would get closer to a 1 A/R on the compressor side or you will too restricted for good thrust/power output; The restriction at turbin rpm is too great.

Rob

hello Rob!

thanks for your info, what are the normal A/R on the turbine housing with that compressor A/R?....do you have any ideas?..i have looked all over the turbine housing without being able to find anything...you seem to know MACKs qite good.....i know about the compressors shortcomings but i have some ideas how to compensate that..its called water/methanol injection......best regards/stephan

Edited by stephan

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hello Rob!

thanks for your info, what are the normal A/R on the turbine housing with that compressor A/R?....do you have any ideas?..i have looked all over the turbine housing without being able to find anything...you seem to know MACKs qite good.....i know about the compressors shortcomings but i have some ideas how to compensate that..its called water/methanol injection......best regards/stephan

I don't know for sure so cannot offer a quantified answer. An educated guess would put the turbine housing into the area between .97A/R, and 1.04 A/R. Again this assumption is based on the torque rise of the "Maxidyne" series of engine off the top of my feeble little mind.

Water/methanol injection will serve to lower your heat of combustion, (temperature, and pressure) thus delaying the rate of expansion of your burnt fuel/air gaseous mixture. As I'm sure you are aware, this action will limit, or drop your available thrust output as a turbojet type of engine depends on the amount of fuel and air it consumes, coinciding with rapid expanding exhaust gasses to further drive the turbine to drive the compressor. The theory of operation manifests itself to the point of destruction from physical limitations. Water/methanol mixtures will help you keep from melting to engine, (a.k.a. turbocharger) itself. Another note is the bearings supporting the turbine and compressor wheel will not hold up very long due to uncontrolled acceleration and rpm's in a stock unmodified turbocharger.

Sure a lot of fun to play with though!

Rob

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I don't know for sure so cannot offer a quantified answer. An educated guess would put the turbine housing into the area between .97A/R, and 1.04 A/R. Again this assumption is based on the torque rise of the "Maxidyne" series of engine off the top of my feeble little mind.

Water/methanol injection will serve to lower your heat of combustion, (temperature, and pressure) thus delaying the rate of expansion of your burnt fuel/air gaseous mixture. As I'm sure you are aware, this action will limit, or drop your available thrust output as a turbojet type of engine depends on the amount of fuel and air it consumes, coinciding with rapid expanding exhaust gasses to further drive the turbine to drive the compressor. The theory of operation manifests itself to the point of destruction from physical limitations. Water/methanol mixtures will help you keep from melting to engine, (a.k.a. turbocharger) itself. Another note is the bearings supporting the turbine and compressor wheel will not hold up very long due to uncontrolled acceleration and rpm's in a stock unmodified turbocharger.

Sure a lot of fun to play with though!

Rob

hello Rob!

thanks for your input about turbojets.....in fact the thrust is increased on a turbojet engine with water injection because that water has to go somewhere and it goes thrue the turbine in the form of steam and oxygen...you know that water is oxygen and nitrogen....it separates here by the heat and it also allowes more fuel to be injected , more total mass flow thrue the turbine means increased thrust on a turbojet engine...the US air force used this method on the Boeing B52 stratofortress bomber and on the boeing KC 135 stratotanker to increase the thrust during liftoff from the runway.

i will use the water/methanol injection at power levels above 3/4 of the throttle....the methanol adding is used to restore the turbine housing and turbine temps so it dont get thermal shock because the methanol will burn inside the engine, enough methanol will be added so the turbine temps be equal to the temps without water/methanol injection....it takes a lot of testing to get there but it can be done.

bearings survive qite good on such an engine, this hobby is a very big hobby in the US and in the UK...i know one guy which has run his engine for over 300 hours....it is a matter of proper tuning, oil supply with the correct oil press (which must be higher than the compressor disharge pressure to avoid the compressor from pulling the turbine shaft against the thrust bearing,destroying it)and with good oil cooling and proper engine monitoring such as all the pressures,oil press and fuel press,the P2(compressor discharge pressure) the P4(jet pipe pressure)and the compressor discharge temp and ofcourse TIT(turbine inlet temp)and TOT(turbine outlet temp) and reading of the RPMs ofcourse to avoid overrevving of the engine(it also helps a great deal in tuning such an engine to read the RPMs when an event is happening at what RPM)and reading of the ambient temps as well is a good help, do all that monitoring then the engine survive.....i have read tons of info on this matter....thanks for your guesstimating of turbine housings, it was to great help in calculating stuff for the engine.......thanks Rob......best regards/stephan

Edited by stephan

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hello Rob!

thanks for your input about turbojets.....in fact the thrust is increased on a turbojet engine with water injection because that water has to go somewhere and it goes thrue the turbine in the form of steam and oxygen...you know that water is oxygen and nitrogen....it separates here by the heat and it also allowes more fuel to be injected , more total mass flow thrue the turbine means increased thrust on a turbojet engine...the US air force used this method on the Boeing B52 stratofortress bomber and on the boeing KC 135 stratotanker to increase the thrust during liftoff from the runway.

i will use the water/methanol injection at power levels above 3/4 of the throttle....the methanol adding is used to restore the turbine housing and turbine temps so it dont get thermal shock because the methanol will burn inside the engine, enough methanol will be added so the turbine temps be equal to the temps without water/methanol injection....it takes a lot of testing to get there but it can be done.

bearings survive qite good on such an engine, this hobby is a very big hobby in the US and in the UK...i know one guy which has run his engine for over 300 hours....it is a matter of proper tuning, oil supply with the correct oil press (which must be higher than the compressor disharge pressure to avoid the compressor from pulling the turbine shaft against the thrust bearing,destroying it)and with good oil cooling and proper engine monitoring such as all the pressures,oil press and fuel press,the P2(compressor discharge pressure) the P4(jet pipe pressure)and the compressor discharge temp and ofcourse TIT(turbine inlet temp)and TOT(turbine outlet temp) and reading of the RPMs ofcourse to avoid overrevving of the engine(it also helps a great deal in tuning such an engine to read the RPMs when an event is happening at what RPM)and reading of the ambient temps as well is a good help, do all that monitoring then the engine survive.....i have read tons of info on this matter....thanks for your guesstimating of turbine housings, it was to great help in calculating stuff for the engine.......thanks Rob......best regards/stephan

Hi Stephan, we are saying the same thing regarding water/methanol injection as far as injection of the fuel to be burnt, the expansion rate of combustion, and using water to cool internal parts to keep from melting. I did know that power is in fact increased with this injection system as I've seen, (and used) it on many different applications. What I meant is that with water/methanol injection is that you can inject much more fuel/air mixture for more power and keep the engine from melting down from the heat of combustion.

Glad to hear you are serious about this hobby as you stated. I've always liked obscure, or different things to experiment with.

I'm sure you meant to say that water is composed of two atoms of hydrogen, and one of oxygen instead of nitrogen. As you know nitrogen is an inert gas and to the best of my knowledge, does not readily support combustion.

Best of luck with your project! What type of fuel are you planning to use, acytelyene, propane, or a liquid type fuel? I would assume that a gaseous mixture as that is what most persons in the hobby try to use.

Rob

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Hi Stephan, we are saying the same thing regarding water/methanol injection as far as injection of the fuel to be burnt, the expansion rate of combustion, and using water to cool internal parts to keep from melting. I did know that power is in fact increased with this injection system as I've seen, (and used) it on many different applications. What I meant is that with water/methanol injection is that you can inject much more fuel/air mixture for more power and keep the engine from melting down from the heat of combustion.

Glad to hear you are serious about this hobby as you stated. I've always liked obscure, or different things to experiment with.

I'm sure you meant to say that water is composed of two atoms of hydrogen, and one of oxygen instead of nitrogen. As you know nitrogen is an inert gas and to the best of my knowledge, does not readily support combustion.

Best of luck with your project! What type of fuel are you planning to use, acytelyene, propane, or a liquid type fuel? I would assume that a gaseous mixture as that is what most persons in the hobby try to use.

Rob

hello Rob!

ofcourse i meant hydrogen,hahaha i got a bit brainwashed there for a while......the fuel which is mostly used is propane because it is a very forgiving fuel for shortcomings in engine combustor designs etc...but many uses real jet fuel as i intend to do as well......i will start up the engine with propane first to get a pilot light...then i slowly opens jet fuel valve and the fuel enters thrue the three fuel injector nozzles that i will use...when engine runs good i close the propane valve(you can see the three marks on the top plate on one of the photos where the fuel nozzles will be placed)....and there you have it.....a miniature turbojet engine running on jet fuel....with the correct smells and everything.

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hello Rob!

ofcourse i meant hydrogen,hahaha i got a bit brainwashed there for a while......the fuel which is mostly used is propane because it is a very forgiving fuel for shortcomings in engine combustor designs etc...but many uses real jet fuel as i intend to do as well......i will start up the engine with propane first to get a pilot light...then i slowly opens jet fuel valve and the fuel enters thrue the three fuel injector nozzles that i will use...when engine runs good i close the propane valve(you can see the three marks on the top plate on one of the photos where the fuel nozzles will be placed)....and there you have it.....a miniature turbojet engine running on jet fuel....with the correct smells and everything.

NOISE! Don't forget the NOISE! This project really sounds like you are into it "full tilt"!

What type of injection pattern are looking at, conical, radial, trapezoidal, and what type of injection pressure are you suspecting to need to meter the fuel spray to the correct injection point target? This optimization will probably need to be derived through analysis, but even burn is essential to eliminate, or minimize supersonic pulses within the combustion chamber.

Would there be a little better outcome if you started with a true "axial flow" engine as opposed to a modified automotive turbocharger? It would seem the total package could be minimized in physical size and this engine installed into something than more of a static display? It would be kinda neat to see a car, or small truck model pushed along with this engine.

Rob

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NOISE! Don't forget the NOISE! This project really sounds like you are into it "full tilt"!

What type of injection pattern are looking at, conical, radial, trapezoidal, and what type of injection pressure are you suspecting to need to meter the fuel spray to the correct injection point target? This optimization will probably need to be derived through analysis, but even burn is essential to eliminate, or minimize supersonic pulses within the combustion chamber.

Would there be a little better outcome if you started with a true "axial flow" engine as opposed to a modified automotive turbocharger? It would seem the total package could be minimized in physical size and this engine installed into something than more of a static display? It would be kinda neat to see a car, or small truck model pushed along with this engine.

Rob

hello Rob!

haha full tilt!....hmmm well, you almost have to be like a mad scientist about it, to endure all that work and testing BUT i have an enormous help in a friend(which sold the turbo to me, he is an retired gas turbine engineer, he used to work for GARRETT propulsion systems for over 40 years)there he designed and developed new types of gas turbines and nowdays he cant let go from it, he continued with gas turbines as a hobby. enormously friendly and helpful man but sometimes when he explains about gas turbines you dont understand much, 40 years around gas turbines makes that.

the injectors are of a hollow cone type pattern.made by HAGO...they work the best for our hobby engines and i plan to run around 250-300 psi fuel pressure to get good atomization...better atomization means cleaner burn and more thrust and cooler running engine...hmmm axial engines?.....mmmm but then it costs a bundle of money and you have to construct everything and then i mean EVERYTHING yourself.....that includes such a critical part as the turbine with its special heat resistant alloys....very very difficult and costly......nah....i stay with ordinary turbos......one day i would want to build a turbojet out of a really BIG turbo such as the garrett gt60 high performance turbo OR small ship turbo or diesel locomotive turbo...othervise it is experimenting until it runs properly..../stephan

Edited by stephan

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hello all.....first i dont own any mack truck BUT i am the owner of a brand new garrett turbocharger model TV61, it is supposed to sit on an mack endt 673 engine, i bought this turbo with the intention to build a turbojet engine and that is my big project in life but i got a bit interested in what kind of truck this turbo would have been used......any info appreciated...best regards/stephan

its the same one on my 57 b model mack.......want to sell it?

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its the same one on my 57 b model mack.......want to sell it?

hello.....you have exactly the same turbo on your B-model truck?......sell it??.....i dont know really....i dont plan to do that, what would you offer for it in that case?, i could find a bigger and better suited turbo ofcourse than this but this one is brand new and in top condition, i really really dont know,now i am confused the combustor which is made is made after measurments and calculations made on this turbo.AND it is an enormous amount of time invested which cant be counted AND alot of money invested as well...its very emotional thing this,as i said earlier if i would sell it and start over with another bigger turbo i would have restart everything with the combustor because the parts made for this engine are suited for this particular turbo....../stephan

Edited by stephan

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hello.....you have exactly the same turbo on your B-model truck?......sell it??.....i dont know really....i dont plan to do that, what would you offer for it in that case?, i could find a bigger and better suited turbo ofcourse than this but this one is brand new and in top condition, i really really dont know,now i am confused the combustor which is made is made after measurments and calculations made on this turbo.AND it is an enormous amount of time invested which cant be counted AND alot of money invested as well...its very emotional thing this,as i said earlier if i would sell it and start over with another bigger turbo i would have restart everything with the combustor because the parts made for this engine are suited for this particular turbo....../stephan

If its what you truley want to do and you believe you can do it, take your time and spend a little here and there, its just a project and not your life. Enjoy your projects and if you need to start over or go back to the drawing board then so be it, its all in fun. If indeed you really want to sell it for whatever reason, name your price and then we can go from there.

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If its what you truley want to do and you believe you can do it, take your time and spend a little here and there, its just a project and not your life. Enjoy your projects and if you need to start over or go back to the drawing board then so be it, its all in fun. If indeed you really want to sell it for whatever reason, name your price and then we can go from there.

hello again!

i could sell it but it would be so expensive so i even dont dare to say for how much, because it would have to pay for the new project turbo then...and it is qite expensive/stephan

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hello all.....first i dont own any mack truck BUT i am the owner of a brand new garrett turbocharger model TV61, it is supposed to sit on an mack endt 673 engine, i bought this turbo with the intention to build a turbojet engine and that is my big project in life but i got a bit interested in what kind of truck this turbo would have been used......any info appreciated...best regards/stephan

Hi Stephan and welcome. A couple of guys in Australia got bored one weekend and did the same thing, but at home with a Cummins big cam turbo, some scrap steel, welder and an LPG gas bottle for fuel supply. Somehow they avoided blowing themselves and everything within 500 yards into orbit. This thing screamed. There was a website around for it, think it was called fulbosjet.net or something like that. Good luck with your hobby, as an ex jet fighter engine tech, I love playing with this sort of thing. Have drawn a few rough plans for a small axial flow zero by-pass engine, but as you say, the turbine gets expensive for materials.

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Hi Stephan and welcome. A couple of guys in Australia got bored one weekend and did the same thing, but at home with a Cummins big cam turbo, some scrap steel, welder and an LPG gas bottle for fuel supply. Somehow they avoided blowing themselves and everything within 500 yards into orbit. This thing screamed. There was a website around for it, think it was called fulbosjet.net or something like that. Good luck with your hobby, as an ex jet fighter engine tech, I love playing with this sort of thing. Have drawn a few rough plans for a small axial flow zero by-pass engine, but as you say, the turbine gets expensive for materials.

hello chris!

thank you,yes i know about some guys in australia myself, one named john wallis build qite impressive engines....even a turboprop engine and shaft powered to power one bike and one gocart.....impressive.../stephan

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I worked on a lot of turbine engines - - -1,100 to 7,700 Hp.

Loved working on them!!

They are not fuel efficent but the horse power that comes from such a small package was impressive!!!

1,100 HP from an engine that will fit in a pick-up.

The small engines were the most problematic.

'Charlie' called them "Whistling S--thouses"

Packer

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i love turbine engines too......perhaps it becomes so when you worked at a fighter squadron..../stephan

I worked on a lot of turbine engines - - -1,100 to 7,700 Hp.

Loved working on them!!

They are not fuel efficent but the horse power that comes from such a small package was impressive!!!

1,100 HP from an engine that will fit in a pick-up.

The small engines were the most problematic.

'Charlie' called them "Whistling S--thouses"

Packer

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