Junkers Ju-52/3m

[aleatorylamp]

New Spanish Supercharger too.

Hello Smilo, Hello Ivan
Thanks, Smilo, for your interest! OK, here´s the .air file for the g4e night flier, attached to this post!Remember, it is the 725 Hp version recovered from the Norwegian lake in 1986, at present in a Norwegian museum, very nicely restored!

OK - now, apart from the other 830 Hp engine pending supercharger correction, the third model
also needs supercharger attention: The Spanish CASA 352L.

This Ju52/3m version has three Elizalde (ENMA) Beta B-4 engines, that deliver 775 Hp at 2200 RPM. They are Spanish licence-built American Wright Cyclone R-1820´s, just like the Russian Shvetsov M-25, of which the Spanish Air Force also had a number for their Polikarpov I-16 Rata/Mosca fighters.

I have found no information whatsoever as to these engines´ manifold pressure, and upto now I had 1.2 ATA (34.87 inches Hg) for want of anything else, and it has worked quite OK.

Nevertheless, I though I´d try and get it better, even if actual model performance will stay the same. So, looking, I found a Power Chart, within a Wright Cyclone R-1820 Engine Overhaul Document - I can´t make head or tail out of it... so many different engine versions ranging from 575 to 1525 Hp... but I enclose it herewith. Perhaps someone can find some use for it!

However, looking further, on an Air Tractor page I found a comment:
Someone was installing a Wright Cyclone R-1820-72 on his M-A1B Air Tractor. Apparently this power-house was going to be a bit much for the crop-duster! 1200 Hp at 2500 RPM, manifold pressure of 45 inches of mercury, would be overdoing it a bit, I suppose...

So, he decided to derate his engine to 900 horsepower, by limiting rpm to 2,300 and manifold pressure to 36 inches, for take-off and for continuous use. This way he was also going to increase its service life.

Interesting piece of information... I could further derate this engine to give me 775 Hp and 2200 RPM. The numbers don´t tally absolutely exactly, so I´ll strike a mean between the two results:

300 rpm less: 45 – 13.5 = 31.50 inches
425 Hp less: 45 - 9.5625 = 35.4375 inches

Average 33.46875 inches, the new Manifold pressure for the 775 Hp Elizalde Beta B-4.
With a slight adjustment on the Torque graph, I can get exactly the performance needed!

Would you think this could be a plausible, acceptable way of going about the matter?
Opinions will of course be very much appreciated!

Here´s a screenshot of the Spanish Ju52/3m for more eye-candy.

Remember, the attached -.air file is for the armed night-flier bomber/transport.

Thanks again, and Cheers,

 

[smilo]

got it, thanks

 

[Ivan]

1 Minute Take-Off Rating

Hello Aleatorylamp,

Have you thought about using the CFS WEP feature to address either the 1 minute or 5 minute power settings?
You can't limit RPM that way, but it is pretty easy to limit Manifold Pressure.
I have been a bit busy lately doing some research and causing trouble in another forum.

- Ivan.

 

[aleatorylamp]

WEP

Hello Ivan,
Well, I hadn´t thought of it... For some odd reason it hadn´t occurred to me.
It would be a good measure to prevent people from just flying around at max. throttle
all the time. It sounds like a good idea!

Perhaps I´ll use WEP option 2, which is less ruthless and in case of abuse, won´t cripple
the engine to a clanking 50% power wreck - it just loses WEP.

Also, it would seem logical to include the both 1-minute and 5-minute power settings into WEP.
The power percentage or span involved is quite large, going from 89% to 100%, (1.02 ATA to
1.25 ATA, i.e. 32.4 to 36.2 inches of mercury), so it seems quite worth while to do it that way.

30-minute power is at 84% throttle, 1.06 ATA, 30.7 inches of mercury. Maybe anything above
that should also be put into WEP.

So the question is as of what power WEP should be implemented: 85% or 89%?
I mean, if you were just going to stay at 88% for half an hour, it should really harm the engine
as well, shouldn´t it?

What would you suggest?
Cheers,
Aleatorylamp

 

[aleatorylamp]

Spanish Supercharger

Hello Folks,
I think I missed something in my calculation for 33.47 MP for the Spanish 775 Hp Beta-B4 engine, derived from the Air Tractor with the derated Wright Cyclone R-1820-72 engine, that I had mentioned in my post yesterday.

I did not take into account that the Air Tractor had a more efficient 3-bladed CV propeller installed. Consequently, the Beta B-4 would require a bit more than 33.47 MP to provide the desired 775 Hp, and now I am thinking that perhaps the original 34.87 (1.2 ATA) was more realistic.

I suppose it´s splitting hairs here a bit, as it were, and the resulting pèrformance curve is of course the same. However, for the sake of technical accuracy, I want use the data that seems more correct. A basically identical engine would be the Wright Cyclone R-1820-33, but I have no tangible MP information.

Anyway, I think I´ll use the 34.87 MP again, unless there´s a different suggestion, so I´m going to adjust the torque graphs accordingly.

Then, for WEP, also for the other two models, it´ll only be a matter of setting the manifold pressures once it´s decided at what throttle percentage WEP has to start.

Cheers,
Aleatorylamp

 

[Ivan]

Hello Aleatorylamp,

It sounds like a good idea for
WEP = 1.25 ATA and
Normal Maximum = 1.06 (30 Minute Rating).

As suggested earlier, that is how I would do it. There isn't very much difference between the 30 minute and max continuous anyway.
The Supercharger boost WEP option is really pretty messed up, so you really have a choice of a 5 minute or 10 minute limit with water or water methanol injection.

This kind of ties in with the discussions I have been having elsewhere:
What happens when an engine needs Water Methanol injection for ANYTHING over its cruise setting?
It may sound a bit stupid, but that is how the Japanese engines worked.
I have an idea which is a little weird but need to test it out in an AIR file first to make sure there are no unintended side effects.

- Ivan.

 

[aleatorylamp]

WEP by Methanol-Water injection

Hello Ivan,
Thanks for confirming! I´ll go about it that way then.
For practical purposes in the sim, I think it will be a simple and good solution.
I expect that Smilo will also agree!

Out of curiosity, I tested whether keeping the throttle at 85% would prolong WEP time allowed, but it´s the same 5 minutes as for 100%. Anyway, it´s partially realistic though, as 84% throttle was allowed for 5 minutes.

What happens with water-methanol injection? I think the engine rusts! ...If used at speeds above cruising, I suppose it would possibly interfere with lubrication and maybe quickly ruin the engine.

It´s not such a stupid idea at all, actually, but do correct me if I´m wrong!

The impression I got was that interestingly enough, methanol performance increase came with the penalty of greater heat, so they injected water to cool that, also obtaining the added thrust of the steam generated. The drawback of all this was I believe greater corrosion resulting in reduced engine life-span, but for military purposes it wasn´t important.

Later, the French did the same with their Turbomeca Bastan VIC turboprop turbines, with similar results, although here there was no methanol, just water. They were actually quite successful, and used them on the Nord 262 commuter/navy patrol aircraft for quite some time.

Here´s a screenshot of one I made for FS98. The lines are quite elegant. (You´ll say Eeek! A jet!!). The Americans modified a few of these with PT6 P&W Canada turboprops and called them Mohawk-298, for use by Allegheny Airlines for some years.

I´m curious as to what idea you may come up regarding water-methanol injection in the flight dynamics!
OK then, cheers,

 

[aleatorylamp]

Hello Ivan, hello Smilo,
OK, the 3 aircraft now have engine performance curves based on the
new one for the 725 Hp Ju52. The curves for the 775 Hp and 830 Hp
versions are similar in shape, and proportionally more powerful, which
is what was being intended. Also, they seem to be behaving themselves
very well!

The implementation of WEP after 84% throttle was no problem, and it
feels much more logical to fly the airplanes this way.
Thanks for reminding me about WEP, Ivan!

So, quite soon I´ll be able to upload the three Antie Ju´s.
Cheers,
Aleatorylamp

 

[aleatorylamp]

Further to the Power Curves

Hello Smilo, hello Ivan,
For the moment, the power curves of the three engines (725, 775 and 830 Hp)
are very accurate at S.L. compared to the specified maximum and cruise powers
for S.L:
All are exactly bang on +/- 0 Hp, except the 830 Hp engine which
is 18 Hp low at 76% throttle.

However, further up, there is some discrepancy with specs:

_9-29 hp low at 3000 ft,
_8-12 Hp high at 4600 ft,
21-30 Hp high at 5600 ft, and
34-43 Hp high at 7200 ft.

Further up, I have no spec. data to go by.

I was trying to figure out a way of evening out the consistent excessive power
from 4600 to 7200 ft in the specs, but could only come up with the idea of
lowering Boost Gain a little, so as to reduce the excessive Hp at 4600, 5600
and 7200 ft., but this is not possible:

The RPM ranges involved overlap with the RPM ranges for 3000 ft, so any
reduction to correct performance further up would further reduce performance there.

The only thing that occurs to me is to either
a) leave it that way, as for simming, a little extra power at the altitudes involved will be fine, or
b) reduce power altitude power a bit the excess, at the expense of losing power lower down.

I´d vote for leaving it as it is, unless you would have a different preference.
What would your preferences be?
Cheers,
Aleatorylamp

 

[smilo]

leave it as it is

 

[aleatorylamp]

Hello Smilo,
Thanks! I think so too. Anyway, the way I did it this time gave a better
envelope than I was getting before.

Just for the sake of curiosity to illustrate it, here´s a compound screenshot
of the propeller graph Table 512 and the Torque graph for the 725 Hp engine.

The difference with the other two more powerful engines is a slightly narrower
"hump", and of course that the right column goes up to 775 and 830 Hp
respectively, in the torque graph and a less pronounced "step" in the propeller
graph.

Note that the "downward hook" on the right is not of the type sometimes used
for curbing power after max. RPM. Some time ago Ivan had recommended not
using it, to allow for a more correctly defined engine power.

If I had had an extra column on the right, after the Max. Power RPM setting, I
would have liked the graph to go on horizontally, but it does that anyway, I suppose.

Eliminating the "hump" and the "step" causes abnormally low cruise powers at
correct maximum power, or conversely, abormally high maximum power at
more correct cruise powers.

So, perhaps it´s as good as it gets, as Jack Nicholson would say...
Cheers,
Aleatorylamp

 

[Ivan]

Hello Aleatorylamp,

The CFS engine dynamics are not perfect. Just do what you can as well as you can.
I am never satisfied with my own flight models, but realise that at some point, I don't know how to make any more improvements.

Later, the French did the same with their Turbomeca Bastan VIC turboprop turbines, with similar results, although here there was no methanol, just water. They were actually quite successful, and used them on the Nord 262 commuter/navy patrol aircraft for quite some time.

Eeeek, a Jet!!!

Regarding water injection on a Turboprop:
I believe this is the same idea as on a regular jet engine and has nothing to do with piston engines.
The idea is to use the combustion heat to superheat water into steam for increased exhaust thrust.

What happens with water-methanol injection? I think the engine rusts! ...If used at speeds above cruising, I suppose it would possibly interfere with lubrication and maybe quickly ruin the engine.

It´s not such a stupid idea at all, actually, but do correct me if I´m wrong!

The impression I got was that interestingly enough, methanol performance increase came with the penalty of greater heat, so they injected water to cool that, also obtaining the added thrust of the steam generated. The drawback of all this was I believe greater corrosion resulting in reduced engine life-span, but for military purposes it wasn´t important.

Now keep in mind that I am certainly no expert in this field.... but I do not believe you are entirely correct.
Gasoline as you know is a Hydrocarbon. There are many impurities, but the important molecules are composed of Hydrogen and Carbon. The byproducts of combustion (oxidation) are H2O and CO2. Thus there already is water vapor in the cylinder as a result of combustion.
The addition of water into the intake system is intended to reduce the combustion temperature and prevent pre-detonation so that higher boost / cylinder pressures can be tolerated without damage to the engine. The higher pressures and stress by themselves will have some effect and I believe this is the cause of increases in engine wear.
The methanol is just an additive to the ADI mixture to prevent it from freezing when the temperature gets too low.

- Ivan.

 

[aleatorylamp]

Hello Ivan,
Thanks for your comment on doing what one can to best get sim engine performance as near as possible to specs!

Re. Water-Methanol: Interesting, and unexpected, what you mention, thanks a lot!
I´d expected that the superheated steam effect that adds thrust to jet turbines (and I know that it does, and it makes them rust more), would also apply in piston engines, as a logical deduction.

However, it was just an impression on my part, and I didn´t know that methanol was only an anti-freeze.

But then, if water and water+methanol is defined as WEP in the sim, don´t these give any added thrust?

From what you say, it appears not to be the case, and in reality the extra power comes only from a higher amount of fuel being burned, with water and water+methanol addition only acting as a retardant and a direct coolant, to counteract the increased heat of the extra fuel.

Wikipedia explains all you are saying in great detail, and makes for a very interesting read!

Then, the difference in the effect between using water and using water+methanol for added power seems to be that although being combustible, methanol has a retarded ignition point and thus helps prevent detonation. Both also seem to allow for higher compression ratios.

Maybe that´s why the allowerd WEP time in the sim is longer for water injection only, than for methanol-water, which is only 5 minutes.

Cheers,
Aleatorylamp

 

[Ivan]

Hello Aleatorylamp,

The WEP in the CFS is gross oversimplification of how things really work.

Even in the case of US aircraft in which only "Water Injection" is available, the reality is that they used methanol as an additive as well.
I believe the limit was "5 minutes" but those quote are because that limit was often stated as 5 minutes but sometimes it was not.
It depended a bit on the engine and some were more tolerant than others.
Note that the REAL limitation was that the engines would typically be generating more heat than they could dissipate and the Cylinder Head Temperatures would be in a range that could only be tolerated for a few minutes without damage.

Note that I mentioned specifically CHT which implies radials.
One of the reasons that Inlines could run for a bit longer by simply raising boost without Anti Detonant Injection (ADI) is because there was more mass to "heat soak": More mass in the cooling system, engine mass, etc. needed to have its temperature raised before bad things started happening.

The Water Methanol injection I believe was intended to represent the German systems used on the FW 190A series. It is a pity that the FW 190A in the game doesn't actually have that feature. Sometimes the limit was 10 minutes and sometimes it was not.
Sometimes the emergency power wasn't even MW50 injection at all.

Life gets really interesting when looking at the Japanese engines because their fuel was so poor (91 or 92 octane) that ADI was required for some engines as soon as their throttle settings went above continuous cruise settings. Thus climb, normal, military and emergency power just differed in allowed duration. All required ADI.

The 5 minute Supercharger WEP is also not realistic. At low level, it MIGHT be pretty close, but above the critical altitude, the engine even with WEP would be using less boost than it would be at sea level and at some altitudes above that, the engine even with WEP engaged would not be using as much boost as it would under continuous power settings at sea level..... And yet the engine would still blow up after 5 minutes 10 seconds.

- Ivan.

 

[aleatorylamp]

Hello Ivan,
Very interesting information, that you supply, and I appreciate your efforts explaining so many details!

I had always wondered why the VW Beetle air-cooled engine with 1200-1600 cc had such a low compression ratio that it only produced 30-50 Hp. So it was to prevent over-heating!

Regarding the sim´s aircraft engines, I suppose that it must have been quite complicated for those who wrote the sim, to cater for so many different kinds of engines within the comparatively few choices offered in the .air file.

Perhaps, given the lower performance of the Pentium I computers in those days, the .air file would have been too demanding on the CPU if further complication had been introduced.

Anyway, after all the feedback and support I´ve been getting from you and Smilo, I think that within CFS1 limits, the different Auntie Ju models have come out quite nicely, and are performing very satisfactorily!

I´m just finishing the Checklists and then I´ll start upload them, the unarmed transport/paratrooper versions first.

I also have to see about the still inaccurate bombing system that the "improved" bomb sight provided, after they had eliminated the g3e´s retractable under-fuselage "stew-pot".

That bomb aimer´s position between the wheels, from what I´ve read, despite a clear view, had a bomb sight that was no good at all for precision bombing, even from the prescribed 500 meters.

To include the "improved" sight in the model, I´ll see if I can modify the B-17´s bomber´s sight and see if that will work at 500 meters with cruising speed.

Another thing they did, was just shove thousands of incendiary bomb-sticks out of the cargo-doors!

Cheers,
Aleatorylamp

 

[aleatorylamp]

Spanish and German Transport versions uploaded.

Hello Folks,
Here are the first two, which will be available at the following links as soon as they are authorized in the Warbirds library:

Ju52/3m g5e unarmed transport/paratrooper aircraft:
http://www.sim-outhouse.com/sohforum...id=19&id=23401

Spanish CASA352-L transport/paratrooper
http://www.sim-outhouse.com/sohforum...id=19&id=23400

I hope you all enjoy the models!
Any constructive criticism will as usual be welcome!

As soon as I´ve figured out a bomb sight for the armed versions these will be uploaded as well.
Cheers,
Aleatorylamp

 

[aleatorylamp]

CFS1 Spanish Air Force CASA-352L (Ju-52/3m).zip

A new entry has been added to Add-Ons Library, category CFS 1 Aircraft Add-Ons

Description: Spanish license-built Junkers Ju-52/3m, built as passenger aircraft, military trainer, logistics, paratrooper and troop transport. A total of 170 CASA352 units were built from 1942 to 1954, the "L" version having the more powerful 775 hp ENMA (Elizalde) Beta B-4 engines and a top speed of 183 mph at sea level.

The last unit was in service until 1974, and another unit was employed by the paratroopers' school in Alcantarilla until the late 70s. Unit 36-8 served with the 36th Wing at Gando Air Base on the Canary Islands, Spain.

Several CASA 352 and 352-L units are on display in very good condition in museums in different countries, and quite a few still fly today. Virtual and Transparent cockpit elements added using SCASM. Includes custom panel with modified engine gauges, RPM and Boost gauges programmed by Ivan.

By Stephan Scholz

To check it out, rate it or add comments, visit CFS1 Spanish Air Force CASA-352L (Ju-52/3m).zip
The comments you make there will appear in the posts below.

 

[aleatorylamp]

CFS1 Ju-52/3m g5e logistics and paratrooper transport.zip

A new entry has been added to Add-Ons Library, category CFS 1 Aircraft Add-Ons

Description: The Ju-52/3m was originally designed as a passenger and cargo aircraft, and extensively used around the world by airlines of many different countries. With the outbreak of WW2, the design was militarized into different versions, including auxiliary bomber, logistics, paratrooper and troop transport, ambulance and even minesweeper.

This unarmed g5e transport version had 3 x 830 Hp engines, a top speed of 183 mph at S.L., and capacity for a maximum of 13 paratroopers or 18 air-transported troops. The livery corresponds to a unit that saw service during the invasion of Crete in 1942.

Several Ju-52/3ms are at present on display in very good condition in museums in different countries, and quite a few still fly today. Virtual and Transparent cockpit elements added using SCASM. Custom panel with customized engine gauges included, RPM and Boost Gauges programmed by Ivan.

By Stephan Scholz

To check it out, rate it or add comments, visit CFS1 Ju-52/3m g5e logistics and paratrooper transport.zip
The comments you make there will appear in the posts below.

 

[smilo]

got 'em, thanks

 

[Ivan]

Hello Aleatorylamp,

I don't know if your conclusion about compression ratio and heat output in the VW engine are reasonable. I suspect that they are not.

I believe the biggest issue with the older computers was not the complexity of the AIR file.
I believe the problem was lack of video rendering speed.

- Ivan.