"Gaskammer" Part Deux

[Kacey]

Well, we haven't visisted this in quite a while and I think I've come across some interesting developments.

I just can't seem to let this rest!

I've been thinking about "Gaskammer" for the last two years. I lost most all of my data files in a computer hard drive "meltdown" this spring, so I've been "rebuilding" most of my analyses.

Of course during this process I've had to revisit "Gaskammer".

I recently came across the attached drawing for the LeRhone 9R rotary aeroengine and an Aeropshere, 1939 explanation for a very interesting feature!

(link supplied) http://stashbox.org/685659/leRhone%209R%28200dpi%29.TIF

Look on the front crankcase cover plate and you will see nine (9) individual "air-intake" scoops. Aerosphere1939 states they were there for increased cooling. I say BA-HUMBUG.

They may have provided that as an off-shoot, however I believe they were there to "increase the positive pressure" in the crankcase and the induction pipes furnishing the fuel/air mixture to the cylinders, cool the mixture somewhat and improve volumetric effiecency.

Take a look at the SIZE of those things! This engine must have been able to run with the primary air-intake tube blocked off.

Blecthley, talk about "over-leaning". This engine would be WAY 'over-leaned" at sea-level if the throtle was opened to fast or to far.

Which puts it into our NEW catagory "over-leaned" altitude engines. (the original two are of course "over-compressed" & "over-dimensioned"). The German "over-compressed" höhenmotorens all had to be throttled
back at sea-level to aviod either or both "detonation" and "over-leaning".

TAZ, as you are aware from the earlier Octane Table I posted, the UR.2/2.a was on the verge of incipient knock so any increase in induction pressure would only increase detonation troubles.

However, the newest revelation of the extreme "over-leaning" condition would accouint for the Dechamps listing in Höhenmotoren table (pg#193) even without a detonation problem. I'm using the definition of a Höhenmotoren as: "an engine that cannot be safely or efficiently operated a sea-level as a trade-off for better and increased performance at a higher altitude".

The more I looked at these SCOOPS the more I felt I was looking at "Gaskammer".

Reportedly, (Dechamps und Kutzbach) "Gaskammer" was capable of increasing power output around 10% (160/145Ps, UR.3a*) - 22% (140/115Ps, UR.2a*). The 10% is easily accounted for by "over-leaning" and, as Blecthley has pointed out in a previous post, even the 22% could be explained by extreme "over-leaning".

Adding that information to the post by GB where Rammjaeger translated a document as follows: "Gaskammer was a phyical separation zone where mixture was sucked by copper tubes going to inlet valves and internal zone where crankshaft was." Well then?

The more I looked at these SCOOPS the more I felt I was looking at "Gaskammer".

As stated before, I don't know, and we haven't found anybody willing to supply information into what "Gaskammer" really was.

But, the more I looked at these SCOOPS the more I felt I was looking at "Gaskammer".

PART Deux and a half :

However, if I were to reverse engineer something called "Gaskammer" I would have done it a little different. I think a BETTER and greater power increase could be brought about by extending W.O. Bentley's 2mm hole in the induction pipe concept.

The attached figure shows how they could have put little scoops on the induction pipes themselves. Actually, they would be only tiny slits or the upper part of the induction pipe flange gasket could have been cut-out to supply a tiny slit opening and the inlet valve elbow piece flange cutdown slightly to create a scoop effect.

As W.G. Noack states in NACA Report #TN-48, which is discussing early supercharging technology and pressure increases to the induction system:

"Figure 3 shows how the engine may be overloaded by the supply of fresh air under high pressure. In these experiments the charging pressures immediately in front of the carburetor amounted to 830, 760 and 720 m. Hg. (curves 1, 2 and 3), the temperatures of the fresh air also directly in front of the carburetor, were 40, 30 and 8 deg C, the exhaust pressure was unaltered, 736 mm. It is evident that slight pre-compressions are sufficient to secure remarkable power increases and to provide the extra energy for the driving of these superchargers with the engine."

Figure#3 in that report shows that with an increase in pressure to the carburetor, from 760mmHg (@msl) to 830mmHg (which is only 1.35 psi), resulted in a power increase of 8.2%@1250rpm (263/243). Which is not all that exciting since the pressure change was 9.2% (830/760). Your at sea-level and your just not going to something for nothing as they say (whoever they are?).

However, if you look at the data for increasing the pressure back to 760mmHg from 730mmHg (~1100' alt.), which is only a 4.1% (30mmHg = 0.58 psi) pressure change you recover a power increase of 10.5% (243/220).

This is what he means by "remarkable power increases"!

I pretty sure you can get the 0.60 - 1.35 psi boost with something similiar to what I designed/described above.

Oh, the other point I forgot to mention was your going to get about a 12-13 Ps increase for just adding the slits just like Bentley did with his 2mm holes. So the "ram-effect" really only needs to supply 140 -13 =127Ps/115Ps=10% increase (UR.2a). Which would be about a 0.75 psi boost, which is what YAVOR stated I might get from a "induction pipe - air ramming" system (previous post).

Oh, well I just thought the "scoops" on the front of the LeRhone 9R were interesting!

Respectfully Submitted,

KC

[YavorD]

Hello, KACEY!
In the case of Le Rhône 9R, the scoops are, probably, opened simultaneously with the suction valves?
Regards,
Yavor

P.S. Le Rhône 18E too

[Greybeard]

Thanks to Kacey for keeping so hard on this question! Drawing he posted and his related comments are enlightening!

IMHO, I agree those scoops make sense only to give some sort of supercharging, providing a room where air pressure is higher, thanks to recover of dynamic energy.

Indeed, about twenty years later, that became a common practice, increasing rated altitude on its own of about 1500 m.

Nice finding!

GB

[Bletchley]

Fascinating KACEY, thank you very much! It is amazing how much there is still to be discovered about these old engines. I think you are probably right about the Gaskammer, it makes good sense to me

I don't think TAZ visits the forum anymore, unfortunatley (at least, I don't think he posts here any more). You could email him, I guess - or send him a message via OTF.

Bletchley