Albert Ball

[centurion]

The 110-hp Le Rhone (and the smaller 80hp Le Rhone) had the propeller mounted on a nosing piece that was integral with the faceplate to the crankcase. The crankshaft terminated in a ball race at the front of the crankcase. This would mean that the cone could have fitted onto the threaded end of the nosing piece and therefore revolve with the engine.

As I said the patent said crankshaft - as all accounts of the CdP say it did NOT revolve this makes more sense

[mickdavis]

As I said the patent said crankshaft - as all accounts of the CdP say it did NOT revolve this makes more sense

I think we've all seen the Patent no.492.971 drawing and am just trying to figure out how the cone could have fitted onto a Le Rhone. It occurs to me that the propeller and cone that Ball was photographed with may not have been from the same aeroplane.

[mickdavis]

As I said the patent said crankshaft - as all accounts of the CdP say it did NOT revolve this makes more sense

I'm finding this interesting and something else has occurred to me. The patent for the CdP is from November 1916, some four months after Nieuport 17s, seemingly so fitted, were delivered to the British services. Presumably the fitment design would have pre-dated July 1916 and I appreciate that patents could be applied for at a later date but could the CdP have been a later refinement of the Nieuport 17 fitment. Have you any contemporary reference to CdP dated pre November 1916?

[centurion]

I think we've all seen the Patent no.492.971 drawing and am just trying to figure out how the cone could have fitted onto a Le Rhone. It occurs to me that the propeller and cone that Ball was photographed with may not have been from the same aeroplane.

The point I was trying, perhaps not very clearly, to make

[gburt]

'centurion'

You state there is no hole in the propeller for a CdP mount to pass through. The propeller's hub is partially covered by Captain Ball’s left hand. To the best of my knowledge all props of that era (and even today - just had one made for my Pup) had a center hole which provided alignment to the propeller mounting hub, it would still be possible to have a mounting piece that passes through the propeller mounting shaft. In this case, though, the bolt washer plate is present, and a close up view (I have a copy of the high res image) shows a flange on it with a dark center. This may be a hole, or simply shadowing from a finger. So your statement may be correct. This might well be the mounting piece for the CdP/spinner.

Over the years I have seen similar discussions about CdP's vs. spinners. Can anyone point me to a contemporary reference (i.e. ca. 1900-1920) that shows a conic device was only a CdP when on a non-rotating mounting piece on a rotary engine? I am not convinced that there is a real difference between the two, in spite of the various forum arguments. Even today well educated members of English society (and most of the early pilots came from shall we say well healed families) used French terms liberally. In fact, most parts of planes still use the French names, ex. Fuselage, aileron, longerons, cockpit, decalage. Nor is slang a new event. IMHO the Brits may have used the term ‘CdP’ as a synonym for ‘spinner’ regardless of its technical definition.

Re: would a device affect flight dynamics and engine cooling?

To the best of my knowledge, every use of a nose cone (regardless of the mount) has improved performance by reducing drag. It may not show as significantly increased speed (wires are a huge source, streamlined less than round, but none the less), but it would allow faster acceleration to Vmax and reduce fuel consumption.

The reason for a rotary design seems to have been primarily to solve cooling issues once they began to cowl radial engines. They appear to have concluded that rotating the engine to an open air position allowed the continued use of a cowl while having a firewall. It is only my guess, but it appears they saw an advantage to both cooling and fume control by putting the engine exhaust cycle while in the down position. Notice that the cooling tunnel of the Sopwith's and the Nieuports was to the underside.

The spinnered cooling issue has a bit more heterogeneous success result. The SSW's had a problem with a Nieuport like engine mounting, but they also used a nearly closed cowl. It improved eventually with adjustable louvers IIRC.

The real issue with cooling in WW-1 was not a lack of entry cross sectional area for air, rather 1) getting it to the fins and then 2) exhausting it. The problem was that just because I have air to the jug does not mean it will flow well around the individual cooling fins. Once they figured out the need for baffling to improve airflow across the fins themselves, which of course is where the real cooling occurs, rotaries were quickly changed back to radials. This was discovered in the post war era.

The second part is the exhausting of the heated air. The air outlet cross sectional area should be ~2 times the size of the inlet for efficient air flow for a typical reciprocating air-cooled engine. This is because the air is heated as it passes over the cooling fins and expands roughly two times its previous volume. No matter how big I make the inlet, the outlet has to match the flowing air volume and if too small, becomes the rate limiting step. For the open cowls of the Nieuport and Sopwith style planes, the inlets were abundant, outlets were probably adequate. Baffling may have been a big boon, although it would have increased rotating mass and that would have made things more complex.

As for a conic shape (whether hemispheric or flat sided cone or anywhere in between) on a radiator cooled plane, the same air volume issues applied. If the cooling was already abundant, but it ran a bit warmer with a drag reducing device in front of the prop, and remembering that we are mainly looking at the SE-5’s and the like, which had adjustable radiator shutters, the shutters could be opened more and cooling improved. If it reduced drag and therefore reduced power demand, a lower power setting would reduce heat production, therefore the same radiator could still provide adequate cooling, assuming it was previously adequate.

An interesting note - today we use much smaller radiators because a) materials a somewhat better and radiate heat faster, but more importantly, airflow through them is markedly improved along with more fin surface area. Dave Blanton designed an engine mod plan and a great reduction drive to use a V-6 in modern planes. The radiator was initially a big honker of a car radiator mounted in one design behind the cockpit and baggage area. They are fairly big in part because of flow, but also because cars have to handle low airflow states frequently in slow moving traffic. When he learned about high efficiency radiators, he could mount them forward. He also correctly surmised that the time spent on the ground was less important, therefore a smaller radiator could be used. But that is another field. Hope this has been useful.

[centurion]

The rotary and the radial should not be confused. The first rotary engines were built some time before the first aircraft,as early as 1888, and were used for powering cars and motorcyles. They had no cooling fins.  Some early radials were water cooled. Cooling whilst doubtless improved by the spin was not the main rationale behind the rotary The rotary's big advantage was its power/weight ratio, partly achieved by the use of a lost oil lubrication system with centripetal effects distributing the oil.   Its main disadvantages were torque, lack of a real throttle and breathing restrictions (air being drawn through the crankcase). This was its true Achilles heel as it was very difficult to produce more than 250hp. As the power demands grew the radial and  inline engines came back into their own.

[gburt]

The rotary and the radial should not be confused. The first rotary engines were built some time before the first aircraft,as early as 1888, and were used for powering cars and motorcyles. They had no cooling fins. Some early radials were water cooled. Cooling whilst doubtless improved by the spin was not the main rationale behind the rotary The rotary's big advantage was its power/weight ratio, partly achieved by the use of a lost oil lubrication system with centripetal effects distributing the oil. Its main disadvantages were torque, lack of a real throttle and breathing restrictions (air being drawn through the crankcase). This was its true Achilles heel as it was very difficult to produce more than 250hp. As the power demands grew the radial and inline engines came back into their own.

Trust me, I am not confused. The first round aircraft engines were not rotaries. They were radials. Aircraft rotaries came later.

And in the context of Captain Ball and military engines, specifically the LeRhone series, yes they had cooling fins. This appears to have been due to testing of unfinned radials leading to too many engine failures (and radiators were looked as as too unreliable early on). Even the Anzani engine used to cross the channel pre-war by Louis Bleriot had cooling fins. A Nice example was at the Oshkosh 2009 AirVenture and was run several times. Funny sounding piece, to say the least. Odd firing cycle.

Your stated advantages of a rotary were indeed real. What is unclear, at least in the reading I have done, is if they were from well planned R&D discoveries or more serendipitous than anything else. But serendipity is better than no dipity at all! Does not change that the major limitation to them in the WW-1 era, which is the coincident context of the thread and my reply, was overheating causing reliability issues for radials

The statement about throttles is correct only for early engines. All Sopwith Pups had carbueretted LeRhone Gnomes. Not sure how early they were used, but certainly no later than spring of 1916. They even had a mixture control (although not called that until the post war era IIRC).

The reason for not being able to generate adequate HP was more an issue of mass effect and rotational speed - structureally the engine could not hold together. Use of cables applied circumferentially still did not prevent cylinders from being thrown.

Over all, yes the choice to return to using radials was multifactorial. The ability to return to them was most affected by the ability to cool them, which allowed them to run at higher RPM and therefore generate more HP, be geared reliably to decrease prop speed as well as provide more torque. This required baffling, not effectively used (possibly not thought of) in WW-1.

[centurion]

Trust me, I am not confused. The first round aircraft engines were not rotaries. They were radials. Aircraft rotaries came later.

And in the context of Captain Ball and military engines, specifically the LeRhone series, yes they had cooling fins. This appears to have been due to testing of unfinned radials leading to too many engine failures (and radiators were looked as as too unreliable early on). Even the Anzani engine used to cross the channel pre-war by Louis Bleriot had cooling fins. A Nice example was at the Oshkosh 2009 AirVenture and was run several times. Funny sounding piece, to say the least. Odd firing cycle.

Your stated advantages of a rotary were indeed real. What is unclear, at least in the reading I have done, is if they were from well planned R&D discoveries or more serendipitous than anything else. But serendipity is better than no dipity at all! Does not change that the major limitation to them in the WW-1 era, which is the coincident context of the thread and my reply, was overheating causing reliability issues for radials

The statement about throttles is correct only for early engines. All Sopwith Pups had carbueretted LeRhone Gnomes. Not sure how early they were used, but certainly no later than spring of 1916. They even had a mixture control (although not called that until the post war era IIRC).

The reason for not being able to generate adequate HP was more an issue of mass effect and rotational speed - structureally the engine could not hold together. Use of cables applied circumferentially still did not prevent cylinders from being thrown.

Over all, yes the choice to return to using radials was multifactorial. The ability to return to them was most affected by the ability to cool them, which allowed them to run at higher RPM and therefore generate more HP, be geared reliably to decrease prop speed as well as provide more torque. This required baffling, not effectively used (possibly not thought of) in WW-1.

But as I said the first rotaries were not for aircraft and had no fins (and predate the first radials), The science museum has examples. Hence the concept of the rotary was not therefore  a cooling issue. The first Gnome prototype aircraft engine also did not have fins. I stand by my statement no real throttle. The excellent Science Museum book on the history of the rotary makes it very clear that the real reason for the demise of the rotary was the breathing limitation and had nothing to do with cooling. This chimes with what I was taught at Rolls Royce during my graduate apprenticeship and was one reason why Sir Henry Royce refused to have anything to do with the concept.