SPAD XII-Canon Collector Plane

[No.23_Starling]

Hi all, I know it's pretty unlikely to ever happen, but I'd would love to see the SPAD XII added as a collector plane. The idea of having a SPAD with a 37mm Puteux cannon firing through the prop in WW1 makes me squeal with delight. Although 300 were originally ordered probably very few were actually delivered, with sources mentioning fewer than 10 on active service at any one time, issued only to the best pilots in the service. That being said, the XII served from 1917 till late in the conflict and scored a number of kills for those who flew it.

 

What I'd love to discuss with the community however is how easily could we model one with the available data and images, given that no examples survive to today? With this task in mind I wrote to Jon Guttman and subsequently David Mechin whom many of you will know from their excellent publications on WW1 aviation.

 

Cockpit & Engine

My first question was on the controls, given that few photos survive of the cockpit in its entirety. David kindly shared what he knew, and what had been asked of him previously by Romain Hugault, author of the excellent Le Pilote a L'Edelweiss. David and his historian contacts found a film of Guynemer showing off his cockpit SPAD XII-Canon prototype to general Franchet d'Esperey (see below) and there's a number of other photos where you can clearly see the controls sticking out.

 

 

Here you can clearly identify the Deperdussin control wheel mentioned in our written sources. David went on to mention that Romain used this and other photos, plus his own personal flying knowledge to sketch the cockpit for his graphic novel. It's as good a guess as any for how it would have looked:

 

In terms of the breach in the cockpit, we have an image of the HS 8CB engine from the Manuel Lage book Hispano Suiza in Aeronautics. This looks very similar to Romain's drawings and might have been one of his sources.

 

 

We also have a number of surviving examples of the controls from other types so we understand how they worked. The anecdotes of smoke filling the cockpit would be awesome to simulate! I'd imagine the ballistics shouldn't be a terrible task as we already have the CL2 big gun and plenty of WW2 guns to use as a template. We know that the barrel was shortened impacting muzzle velocity and accuracy, not to mention recoil. Either way a single hit on a WW1 plane from a 37mm shell is goodnight.

 

Performance

This is a tricky one as the only data source I have for the XII is the Davilla/Soltan book French Aircraft of the First World War where the performance would seem to lie somewhere between the SPADVII 150hp and 180hp. This seems odd given that her loaded weight was only 30kg more than the SPAD XIII 8BC engine, and we have sources (Air International 10) mentioning that she was regarded as a standard type receiving a high compression upgrade in late 1918 alongside the XIIIs, and must still have been considered competitive even at the late stages of the conflict. Guynemer also noted in early 1917 flights that he managed 137mph at ground level, and took it up to 23,000 feet (Guttman, SPAD XII/XIII Aces of World War 1). That's faster than the VII 180hp at 2,000m according to Davilla/Soltan. I've included their data for the XII but I think it's wrong or on the low side. Does anyone have a better source?

 

Guynemer clearly loved the plane as it was built for him, referring to it as his "avion magique". With that in mind I would be surprised if speed and climb were the bigger issues around performance, and probably more likely the control and weapon arrangement which required the skill of the best allied pilots. It's no coincidence then that pilots like Fonck and Guynemer few the XII each scoring several kills with the type. Charles Biddle noted that the gun was hard to use, and that it handled differently from the XIII, and the RFC who were given one example had a test pilot describe it as being nose-heavy and "soggy", the latter likely explained by the engine/canon arrangement.

 

 

Visuals

There's tons of visuals in Guttman's book, Davilla/Soltan, and others - this shouldn't be an issue for the 1C developers. I actually think the staggered wings make it the most beautiful of all SPADs. Modelling the plane in CAD shouldn't be a huge job and I'd expect the existing VII model to be a starting point for the devs, much like the 109 variants in Great Battles. Davilla/Soltan provide some clear visuals:

 

 

 

Conclusion

With a bit more data (please, please, please share if you have any) I think we could have a really fun and unique collector plane which was flown by most of the top SPAD aces from various nationalities right up to the war's end and it accounted for a number of kills, possibly more than some of our upcoming collector planes. It won't be for everyone, but that's the idea behind DLCs. It would also be the natural mount for the 3PG 100+ kill veterans :-).

 

Let me know your thoughts!

 

[J2_Seya]

Yeah I like this. Please make it

[No.23_Starling]

Update: I found a technical sketch of the cockpit on this site http://www.wwi-models.org/Photos/index.html I’ve asked the admin where they got the sketch - there’s a hint of an original technical drawing.

 

Also there’s a hint to how these controls worked in some replicas with similar early controls like this one here at 3’40”

 

Edited August 15, 2022 by US103_Rummell

[ZachariasX]

From what I know is that of that control wheel, only the top arch was present (more like a yoke in a Cessna), as the lower part of the wheel would in practise interfere with the cannon breech. Also, there was not a central stick (also that would be in the way of the breech), but the mount of the yoke was portruding from the side wall to move the stick all the way to the side. Firing that gun in this tight compartment with the breech right between one‘s legs must have been something not for the faint of the heart.

[No.23_Starling]

1 hour ago, ZachariasX said:

From what I know is that of that control wheel, only the top arch was present (more like a yoke in a Cessna), as the lower part of the wheel would in practise interfere with the cannon breech. Also, there was not a central stick (also that would be in the way of the breech), but the mount of the yoke was portruding from the side wall to move the stick all the way to the side. Firing that gun in this tight compartment with the breech right between one‘s legs must have been something not for the faint of the heart.

Ah amazing! Do you know where you read about just the top arch being present? It looks like Romain might have got it wrong in his comic. I did wonder why you'd want a whole wheel when you need the space underneath to reach the canon.

[ZachariasX]

9 hours ago, US103_Rummell said:

Ah amazing! Do you know where you read about just the top arch being present? It looks like Romain might have got it wrong in his comic. I did wonder why you'd want a whole wheel when you need the space underneath to reach the canon.

I think it was book on Guynemer. I read it quite a while ago. A library loaned book as it wasn't available at the time on sale. It has the only photo of a SPAD XII cockpit that I know of and it may well be that it is from the film you mentioned. But as said, that is my recollection any maybe I'm mixing something up, I'm not getting younger after all.

 

Some more literate people over at the Aerodrome have even reproduced an image of what I think is indeed a also SPAD XII cockpit. If it was a round, full wheel, then it must have gone very low and basically obstruct the breech of the cannon:

https://www.theaerodrome.com/forum/showthread.php?t=34216

 

On this photo, it appears wider than from what can be seen on the pic you posted. It would be nice to see the film you mentioned. maybe it lands on YT one day...

"what  is this" is the rail to hold the gun camera like for Guynemers aircraft.

 

You can see the camera on Guynemers SPAD VII:

 

As gilles says (see referenced thread), Kodak made the camera specifically for him. He and Nungesser routinely took some pictures with it during partols. But I guess in total not that many and I have never seen one of those.

 

If it is really a Deperdussin style control arrangement, then I would expect control sticks to the left and the right of the pilots legs that join centrally where the aileron control wheel is located and as the comic drawing you posed correctly illustrates. It definitely reproduces the Deperdussin arrangement, but not how I would think it would work in the SPAD XII. That the stick was moved to the right side like in the P-38 was my guess, as it would facilitate the picking up of new shells that I think were stored in that tiny cockpit to the left of the pilot to be placed in the breech underneath the yoke after the spent cartridge was possibly thrown overboard. If there was a colum to the left as well, that would be an open invitation to block controls should a shell come loose as well as it restricts places where you actually can put something and grab it in flight. But it may well be so. But with the full wheel, I don't think it would be possible to manipulate the breech of the cannon without two more elbows. The drawing you posted shows this, but I am not that sure that it is even as exact as the lenght indications may allude.

 

Here are some detailed photos of the engine and the cannon of Guynemers SPAD XII:

https://www.histavia21.net/amaviapag/37 mm S.P.A.D Canon.htm

 

As the cannon was semi automatic, each round had to be placed in the breech manually, while discarding the spent cartritge overboard. How much of a "special ineterest" the whole affair was can be seen by the ornaments on the shells (from link above):

Pursuit Group 4 and Pursuit Squadron 13. I mean, who does that in a war of attrition?

 

The whole shell. Infantry got bland deliveries...

 

 

[BMA_Hellbender]

4 hours ago, ZachariasX said:

As the cannon was semi automatic, each round had to be placed in the breech manually, while discarding the spent cartritge overboard. How much of a "special ineterest" the whole affair was can be seen by the ornaments on the shells (from link above):

Pursuit Group 4 and Pursuit Squadron 13. I mean, who does that in a war of attrition?

 

The whole shell. Infantry got bland deliveries...

 

Damn that's a big shell. I bet you only need like 2-3 hits to cause moderate damage to a single wing of a Fokker Dr.I.

[ZachariasX]

1 hour ago, =IRFC=Hellbender said:

 

Damn that's a big shell. I bet you only need like 2-3 hits to cause moderate damage to a single wing of a Fokker Dr.I.

So typical. As soon as they see a big slug, they get opimistic.

[RNAS10_Mitchell]

7 hours ago, ZachariasX said:

I think it was book on Guynemer. I read it quite a while ago. A library loaned book as it wasn't available at the time on sale. It has the only photo of a SPAD XII cockpit that I know of and it may well be that it is from the film you mentioned. But as said, that is my recollection any maybe I'm mixing something up, I'm not getting younger after all.

 

Some more literate people over at the Aerodrome have even reproduced an image of what I think is indeed a also SPAD XII cockpit. If it was a round, full wheel, then it must have gone very low and basically obstruct the breech of the cannon:

https://www.theaerodrome.com/forum/showthread.php?t=34216

 

On this photo, it appears wider than from what can be seen on the pic you posted. It would be nice to see the film you mentioned. maybe it lands on YT one day...

"what  is this" is the rail to hold the gun camera like for Guynemers aircraft.

 

You can see the camera on Guynemers SPAD VII:

 

As gilles says (see referenced thread), Kodak made the camera specifically for him. He and Nungesser routinely took some pictures with it during partols. But I guess in total not that many and I have never seen one of those.

 

If it is really a Deperdussin style control arrangement, then I would expect control sticks to the left and the right of the pilots legs that join centrally where the aileron control wheel is located and as the comic drawing you posed correctly illustrates. It definitely reproduces the Deperdussin arrangement, but not how I would think it would work in the SPAD XII. That the stick was moved to the right side like in the P-38 was my guess, as it would facilitate the picking up of new shells that I think were stored in that tiny cockpit to the left of the pilot to be placed in the breech underneath the yoke after the spent cartridge was possibly thrown overboard. If there was a colum to the left as well, that would be an open invitation to block controls should a shell come loose as well as it restricts places where you actually can put something and grab it in flight. But it may well be so. But with the full wheel, I don't think it would be possible to manipulate the breech of the cannon without two more elbows. The drawing you posted shows this, but I am not that sure that it is even as exact as the lenght indications may allude.

 

Here are some detailed photos of the engine and the cannon of Guynemers SPAD XII:

https://www.histavia21.net/amaviapag/37 mm S.P.A.D Canon.htm

 

As the cannon was semi automatic, each round had to be placed in the breech manually, while discarding the spent cartritge overboard. How much of a "special ineterest" the whole affair was can be seen by the ornaments on the shells (from link above):

Pursuit Group 4 and Pursuit Squadron 13. I mean, who does that in a war of attrition?

 

The whole shell. Infantry got bland deliveries...

 

 

Shell casing art work is pretty documented.   Iirc, mostly done in the trenches.  Pretty sure it was done on spent casings,not live rounds though.

[LukeFF]

33 minutes ago, RNAS10_Mitchell said:

Shell casing art work is pretty documented.   Iirc, mostly done in the trenches.  Pretty sure it was done on spent casings,not live rounds though.

 

A friend of mine has a 37 mm shell with artwork on it that was created by a relative of his who was in an American artillery unit during the war. It's a full intact round, albeit without the powder charge. I'll have to take some photos of it the next time I visit.

[No.23_Starling]

5 hours ago, =IRFC=Hellbender said:

 

Damn that's a big shell. I bet you only need like 2-3 hits to cause moderate damage to a single wing of a Fokker Dr.I.

Romain Hugault thinks a single shell would have done it:

 

Zach, thanks so much for this link https://www.histavia21.net/amaviapag/37 mm S.P.A.D Canon.htm there's some really amazing stuff here with detailed photos and explanations of the 37mm canon. You can clearly see how it looks with the breach opened and closed, plus there's some description on the operation and how it managed recoil. Looks like once fired the shell automatically shot out into the cockpit along with the fumes (sorry for the crap translation):

 

"The weapon must be manually reloaded after each shot. The barrel at rest is in the advanced position, its block breech falling in the low position, the hammer is cocked..
 The pilot supplies the weapon whose chamber is open and he reassembles the breech closure. He checks the cocking of the hammer and activates the firing control via a flexible "Bowden" cable. The hammer is thrown forward and strikes the firing pin. At the start of the shot, the barrel recoils, compressing the shock absorber system.
 The damping system returns the barrel to the forward position, releases the breech closure which returns to the lower position and allows the ejection of the fired casing, probably in an ad hoc receptacle, still not identified with certainty..."

 

This author mentions the 10-12 rounds being stored to the right of the cockpit in a small rack which would have Hagualt's vision of the layout more or less correct with a kind of P38 column offset to the left.

"In the context of aerial combat combining stress and concentration, each cartridge had to be taken from an ad-hoc rack, which contained 10 to 12 munitions depending on the sources and was located on the right in the cockpit, introduced into the chamber and operate the gun controls. The breech block was between the pilot's legs, he had to keep them wide apart so as not to interfere with the movement back and forth of the moving assembly. The weapon after the shot remained open breech, the automatic ejection of the casing, the heavy recoil and the significant smoke development in the passenger compartment will also turn out to be extremely inconvenient."

 

 

Lastly the author mentions that the canon got a rifling modification in early 1918, probably because the short barrel proved inaccurate:

 

"The weapon will undergo at least two known modifications giving rise to recalls, the first consisting in a change of a piece of the brake rods on April 12, 1918, a second major directly linked to combat experience which will consist in replacing the barrel rifled by a smooth barrel from manufacture...."

 

I'm very curious to find that source you mention on the half wheel which really makes sense to make room for the canon. I'm going to buy a few books online about Guynemer and see if I can find the one you read.

 

Do you have anything on performance data?? That's the other big missing piece here as I only have Davilla as a source.

 

 

[ZachariasX]

2 hours ago, US103_Rummell said:

Do you have anything on performance data?? That's the other big missing piece here as I only have Davilla as a source.

Nothing solid apart from the engines that were used as mentioned in the articles above. Along with the known wing modifications, one could both extrapolate from the SPAD XIII.

 

To me it seems that on one hand there was the speed and climb penalty from 20% less power added to the lesser control authority. On paper slightly inferior to the XIII, in practise a highly questionable aircraft.

 

I was looking into the Kindle versions of the Nungesser books, but I am hesitant to buy any as often they don‘t have the rights to reproduce (some of) the pictures…

[ST_Catchov]

4 hours ago, US103_Rummell said:

Romain Hugault thinks a single shell would have done it:

 

Totally unrealistic. The dr1 would just do a snap roll and fly off.

[No.23_Starling]

In terms of the performance, I'm still trying to understand the performance data given by Davilla. I'm hoping @Holtzauge or @=IRFC=Hellbender might have a view on this.

It had the same output as the early 200hp SPAD XIII which we have in game (we dont have the 220hp SPAD contrary to the naming, as @US103_Baer has shown in his analysis in the bug section.

 

Davilla gives the climb to 2000m taking 15% longer than the XIII, despite a loaded weight increase of only 3%. In contrast Davilla only gives the speed difference as a 4% drop compared to the XIII at 2000m (203km/h vs 211km/h) which levels with the weight handicap. As I've stated above, we know from records that the XII received the 1918 high compression upgrade and was still on front line service at the armistice which tells us she was still considered competitive.

 

Any idea why the climb rate in Davilla is so materially different in ratio to weight vs speed with the 200hp XIII?

 

[jeanba]

17 minutes ago, US103_Rummell said:

In terms of the performance, I'm still trying to understand the performance data given by Davilla. I'm hoping @Holtzauge or @=IRFC=Hellbender might have a view on this.

 

Don't

Look for other sources of data which at least will give you the exact context of the test.

I have some ideas, but no proof :

STATISTICALLY, we often find in test report cases of overheating engines wheng doin some climb test (more often than max speed tests), so this may be the case.

This would indicated in the full report.

Be careful that what I wrote is only an example of why you should find more information on the test, I absolutly don't know if it is the right explanation.

Edited August 26, 2022 by jeanba

[No.23_Starling]

On 8/26/2022 at 12:17 PM, jeanba said:

Don't

Look for other sources of data which at least will give you the exact context of the test.

I have some ideas, but no proof :

STATISTICALLY, we often find in test report cases of overheating engines wheng doin some climb test (more often than max speed tests), so this may be the case.

This would indicated in the full report.

Be careful that what I wrote is only an example of why you should find more information on the test, I absolutly don't know if it is the right explanation.

Good point. The challenge is that Davilla is the only source I can’t find at all with performance on the XII and they don’t footnote, only provide a huge bibliography at the end of the book. Anyone have any idea where sources might be for performance data on SPAD aircraft tests?

BTW I think the Davilla data is still pretty good, it’s just that climb rate which is a bit suspect 

[BMA_Hellbender]

Engine performance is such a fickle thing in this game, we have the Camel and Triplane as well as the Dr.I and D.VIII who share engines and yet different static RPM, so really who’s to say?

 

I’m sure enough data exists for the devs to create this plane, and sure why not? It’s something of a variant of both the VII and the XIII, though the strange control system and gun loading animations aren’t exactly cut and paste. Really interesting machine, though, I just hope that your interest in it isn’t mostly due to the faults in the DM and needing cannons to shoot down certain Central planes. I cannot imagine that this type of single shot cannon was more effective than twin Vickers in real world scenarios.

[No.23_Starling]

2 hours ago, =IRFC=Hellbender said:

Engine performance is such a fickle thing in this game, we have the Camel and Triplane as well as the Dr.I and D.VIII who share engines and yet different static RPM, so really who’s to say?

 

I’m sure enough data exists for the devs to create this plane, and sure why not? It’s something of a variant of both the VII and the XIII, though the strange control system and gun loading animations aren’t exactly cut and paste. Really interesting machine, though, I just hope that your interest in it isn’t mostly due to the faults in the DM and needing cannons to shoot down certain Central planes. I cannot imagine that this type of single shot cannon was more effective than twin Vickers in real world scenarios.

Fair point on the engine performance. The canon survives in museums and it looks like they’re happy to show the action to visitors if the photos are to be believed. We have most of what we need for the Deperdussin control except for where the column was attached (left?) and whether it had the bottom quarter removed.

 

As much pleasure as I would take in dealing with adamantium Fokkers and Dr1s using a 37mm, I’m more thinking of how it could be used like an Me210 or bomber interceptor. Would make taking out recons and Gothas a far less risky affair. 

[No.23_Starling]

On 8/27/2022 at 7:49 PM, =IRFC=Hellbender said:

Engine performance is such a fickle thing in this game, we have the Camel and Triplane as well as the Dr.I and D.VIII who share engines and yet different static RPM, so really who’s to say?

 

I’m sure enough data exists for the devs to create this plane, and sure why not? It’s something of a variant of both the VII and the XIII, though the strange control system and gun loading animations aren’t exactly cut and paste. Really interesting machine, though, I just hope that your interest in it isn’t mostly due to the faults in the DM and needing cannons to shoot down certain Central planes. I cannot imagine that this type of single shot cannon was more effective than twin Vickers in real world scenarios.

 

Thanks to Mr @US103_Baer for some further sources. It looks like the Davilla data is flawed and possibly from an early test when the engine had pretty odd gearing as the engineers struggled with the canon configuration at 2000/1186:

 

 

In subsequent engines HS fixed this and also gave her the 1918 high compression 220hp upgrade:

 

 

In Spad Fighters in Action by John F. Connors we find the performance data recorded by Guynemer. It matches the limited data given by Jon Guttman in Spad XII/XIII Aces of World War 1 and pads out the performance data:

 

You'll notice this neatly matches the SPAD XIII 200hp data given by Davilla rather well, and is most likely a more accurate source given the 3% weight difference between the two types:

 

 

Given that we are soon to be getting the SSW which Jack Herris' book (thanks @J99_Sizzlorr) counts 3 active on the front in August 1918, there's just as much reason to include the SPAD XII as a collector, and it can also span the entire period covered right now in Flying Circus volumes i and ii (ideally with engine variants for 200hp and 220hp).

 

I now just need to find out about the control wheel and whether the bottom section was cut out as suggested by @ZachariasX.

 

[US103_Baer]

Nice work. Goes to show how multiple data points reveal a more accurate picture.  

 

Also underlines that we are missing a proper 220hp Spad XIII in the game. But that's off-topic of course.  

 

I'd buy a XII if they made it. Probably tricky to fly and attack with though. 

Edited August 31, 2022 by US103_Baer

[J99_Sizzlorr]

16 hours ago, US103_Rummell said:

[...]

Given that we are soon to be getting the SSW which Jack Herris' book (thanks @J99_Sizzlorr) counts 3 active on the front in August 1918, there's just as much reason to include the SPAD XII as a collector, and it can also span the entire period covered right now in Flying Circus volumes i and ii (ideally with engine variants for 200hp and 220hp).

[...]

 

 

To have a complete picture about the Siemens Schuckert D.IV: Only 3 were active in August 1918 true, but about 280 were ordered from the Siemens Schuckert Werke. From those 280 planes 123 were build and 60 went to the front to be used by the Jastas until the end of the war. How many Spad XII made it into frontline service? Maybe 10?

 

Edit: What I gathered is that 1000 Spad XII were initially ordered but only 20 were build. the Spad XII was difficult to fly and the breach loaded one shot cannon was difficult to aim, produced a heavy recoil and filled the cockpit with smoke. But those who flew it were relatively successful in spite of these problems and the troublesome geared Hispano Suiza engine.

Edited August 31, 2022 by J99_Sizzlorr

[ZachariasX]

14 minutes ago, J99_Sizzlorr said:

Maybe 10?

Maybe 10, but the few ones that flew those 10 shot down aircraft in numbers as 100 regular pilots would tally up.

[J99_Sizzlorr]

38 minutes ago, ZachariasX said:

Maybe 10, but the few ones that flew those 10 shot down aircraft in numbers as 100 regular pilots would tally up.

Rummell's argument was that 3 Siemes Schukerts were active in August and that therfore there is as much reason for the Spad XII to be develeoped as a collector plane of which only 10 planes were active at the frontline service. I just wanted to show that Rummell didn't give a complete picture of the situation as he mostly does. Nobody was talking about how many planes were shot down by any of the two planes. Fever, parasites and infection also killed a lot people on the frontline. Maybe we should have this moddeled as well ?

On a more serious note I think because of the armament being so uinique and therefore has to be completly worked up from scratch we are not likely to see the Spad XII anytime soon if at all. Even though it would be cool to have them. Something the Schuckert could bounce at 7000m

Edited August 31, 2022 by J99_Sizzlorr

[No.23_Starling]

35 minutes ago, J99_Sizzlorr said:

Rummell's argument was that 3 Siemes Schukerts were active in August and that therfore there is as much reason for the Spad XII to be develeoped as a collector plane of which only 10 planes were active at the frontline service. I just wanted to show that Rummell didn't give a complete picture of the situation as he mostly does. Nobody was talking about how many planes were shot down by any of the two planes. Fever, parasites and infection also killed a lot people on the frontline. Maybe we should have this moddeled as well ?

I get your point that records show it’s likely that <50 XIIs of the 300 odd ordered ever made it to the front, and that the SSW had many more on order even if very few saw active service. That being said, you couldn’t use it across all the 1917-1918 maps we have now, limiting it to verrrrry late war, and we don’t know how many SSW.IVs would have made it to the front. The book from Herris you recommended me and use yourself for FC maps notes that the D.VI parasol would have most likely replaced the D.IV is production in early 1919. I considered this point when making the comparison.

 

That being said, in RoF we had plenty of interesting planes which saw service in limited numbers like the big birds (<100 Russian Muromets). They’re there because they’re interesting and did play a role in the war, even if was a minor one. In the case of the XII the canon through the nose was a significant development leading to many ww2 types using the same setup including the most mass produced fighters of all time. From a historical perspective that makes it an important type.

Edited August 31, 2022 by US103_Rummell

[J99_Sizzlorr]

17 minutes ago, US103_Rummell said:

I get your point that records show it’s likely that <50 XIIs of the 300 odd ordered ever made it to the front, and that the SSW had many more on order even if very few saw active service. That being said, you couldn’t use it across all the 1917-1918 maps we have now, limiting it to verrrrry late war, and we don’t know how many SSW.IVs would have made it to the front. The book from Herris you recommended me and use yourself for FC maps notes that the D.VI parasol would have most likely replaced the D.IV is production in early 1919. I considered this point when making the comparison.

 

That being said, in RoF we had plenty of interesting planes which saw service in limited numbers like the big birds (<100 Russian Muromets). They’re there because they’re interesting and did play a role in the war, even if was a minor one. In the case of the XII the canon through the nose was a significant development leading to many ww2 types using the same setup including the most mass produced fighters of all time. From a historical perspective that makes it an important type.

 

We know that 60 SS D.IV made it to the frontline, not from Jack Herris but from other sources. Also the first Siemens Schukert arrived at the frontline in April 1918 for testing with the Jastas so technically not only verrrry late in the war...About the parasol that is if the war continued which thankfully it didn't.

The drop tank on the parasol looks nice btw...

Edited August 31, 2022 by J99_Sizzlorr

[No.23_Starling]

8 minutes ago, J99_Sizzlorr said:

We know that 60 SS D.IV made it to the frontline, not from Jack Herris but from other sources. Also the first Siemens Schukert arrived at the frontline in April 1918 for testing with the Jastas so technically not only verrrry late in the war...About the parasol that is if the war continued which thankfully it didn't.

If 60 had been present by the armistice that’s still peanuts compared the the DVIIs etc and still makes it a relative niche plane, particularly if it was quickly replaced by the parasol - thank God the war didn’t go on longer.

 

I think it’s great we are getting it and would love to see more niche types. We already have canon armed CL2s in large numbers in FlugPark ?

[J99_Sizzlorr]

8 minutes ago, US103_Rummell said:

If 60 had been present by the armistice that’s still peanuts compared the the DVIIs etc and still makes it a relative niche plane, particularly if it was quickly replaced by the parasol - thank God the war didn’t go on longer.

 

I think it’s great we are getting it and would love to see more niche types. We already have canon armed CL2s in large numbers in FlugPark ?

Yeah but we don't have fixed mounted one shot one. It is still peanuts compared to the amounts of Fokker D.VII's but it did out perform the D.VII and was considerd the best fighter in the conflict, which makes it somewhat iconic. I am all with you on having those niche aircrafts I find them very interesting but i still doubt that we will get that. But who knows I didn't believe we will get a Siemes Schuckert too.

Edited August 31, 2022 by J99_Sizzlorr

[No.23_Starling]

44 minutes ago, J99_Sizzlorr said:

Yeah but we don't have fixed mounted one shot one. It is still peanuts compared to the amounts of Fokker D.VII's but it did out perform the D.VII and was considerd the best fighter in the conflict, which makes it somewhat iconic. I am all with you on having those niche aircrafts I find them very interesting but i still doubt that we will get that. But who knows I didn't believe we will get a Siemes Schuckert too.

I was surprised too at the SSW and the Snipe; it’ll be really interesting to see how they perform. Hopefully that’s a sign of things to come ?

 

As for the one shotting with canon, you should have a chat with J30’s gunners! They’re quite good at it :-S

[Holtzauge]

On 8/26/2022 at 1:05 PM, US103_Rummell said:

In terms of the performance, I'm still trying to understand the performance data given by Davilla. I'm hoping @Holtzauge or @=IRFC=Hellbender might have a view on this.

It had the same output as the early 200hp SPAD XIII which we have in game (we dont have the 220hp SPAD contrary to the naming, as @US103_Baer has shown in his analysis in the bug section.

 

Davilla gives the climb to 2000m taking 15% longer than the XIII, despite a loaded weight increase of only 3%. In contrast Davilla only gives the speed difference as a 4% drop compared to the XIII at 2000m (203km/h vs 211km/h) which levels with the weight handicap. As I've stated above, we know from records that the XII received the 1918 high compression upgrade and was still on front line service at the armistice which tells us she was still considered competitive.

 

Any idea why the climb rate in Davilla is so materially different in ratio to weight vs speed with the 200hp XIII?

 

 

@US103_Rummell: A bit late to the party since I have been out sailing for a couple of weeks, but nice to see some performance numbers being discussed. 

 

The climb time of 23 m 13 s to 5000 m for the 220 hp SPAD 12 at a weight of 883 kg seems off: I get a significantly lower climb time of only 19.6 m to 5000 m for the SPAD 13 model (the only one I have in the C++ code) assuming the same weight and engine. As a reference point, for the vanilla SPAD 13 with a weight of 856 kg and a 220 hp engine I get a climb time a bit over 18 m to 5000 m and a ceiling of 6800 m in my simulations.

 

Another thing that seems strange for the SPAD 12 is the ceiling value of 6850 m which is the same as for the SPAD 13 which is lighter. If I raise the weight of my SPAD 13 model to 883 kg I get a lower ceiling: 6500 m which makes more sense I think than the SPAD 12 at 883 kg having the same ceiling as the SPAD 13 at 856 kg. Long story short: The SPAD 12 climb number and ceiling does not make any sense to me unless the SPAD 12’s dimensions such as span and wing area were fundamentally different which I don’t think they were?

 

So in summary: The SPAD 12 having the same ceiling as the lighter SPAD 13 but at the same time needing all off 23.2 m to reach 5000 m does not compute.

 

Edited September 1, 2022 by Holtzauge

[BMA_Hellbender]

@Holtzauge

 

The SPAD 12 and 13 never used the same engine, the 12 had the specially developed 220hp H-S 8BeC(annon) with the cannon built inside, whereas most production SPAD 13s operated with a 200hp H-S 8Bb/c. Later versions of the 13 had the 220hp H-S 8Bd.

 

I don't believe that those later "high compression" engines performed any better at sea level than their non-overcompressed counterparts, unlike what happens in the sim.

[J2_Trupobaw]

The main difficulty of flying Spad XII was unorthodox control system and difficulty of reloading the cannon while flying. Neitherr of which can really be simulated. Best we could hope for is more of  "fighting with overwing Lewis pointed up and reloading it during combat maneuvers" sillyness.

[ZachariasX]

9 hours ago, =IRFC=Hellbender said:

I don't believe that those later "high compression" engines performed any better at sea level than their non-overcompressed counterparts, unlike what happens in the sim.

Why not? Upping compression directly improves engine efficiency at any (reasonable) altitude. The same engine with just higher compression has more shaft hp. Conversely, losing compression directly makes the engine lose shaft hp. You need to do something wrong in other places to end up with the same power again after raising compression.

 

Those later German "over-compressed" engines are just ordinary engines that, through various means, are de-rated at lower levels. Birkigt built his engines to full spec at all altitudes with all the compression he could have for it. Which was less than applied in the German engines. But upping compression they all did. And I'm certain they did it to get the power and not just the hassle.

[No.23_Starling]

11 hours ago, J2_Trupobaw said:

The main difficulty of flying Spad XII was unorthodox control system and difficulty of reloading the cannon while flying. Neitherr of which can really be simulated. Best we could hope for is more of  "fighting with overwing Lewis pointed up and reloading it during combat maneuvers" sillyness.

You could include aspects like the cockpit filling with smoke for a few seconds and a recoil shake. As for the Lewis, you could make it so the plane has to be autolevelled before it lets you change the drum. How hard would that be to model? Couldn’t be that difficult. In CloD they model aspects of moving controls which would require two left hands etc, and that game is relatively ancient.

 

I don’t see why a control wheel would be that much harder to fly with than a stick. I fly light aircraft with both and it’s never given me a problem. Reloading a canon between your legs wouldn’t be too tough if you could level out without worry - harder to do in combat. I’ve had to do all sorts of things whilst airborne, admittedly with the help of trim.

[ST_Catchov]

13 hours ago, J2_Trupobaw said:

"fighting with overwing Lewis pointed up and reloading it during combat maneuvers"

 

Are you saying the Se5a is capable of combat manoeuvres ?

[Holtzauge]

14 hours ago, =IRFC=Hellbender said:

@Holtzauge

 

The SPAD 12 and 13 never used the same engine, the 12 had the specially developed 220hp H-S 8BeC(annon) with the cannon built inside, whereas most production SPAD 13s operated with a 200hp H-S 8Bb/c. Later versions of the 13 had the 220hp H-S 8Bd.

 

I don't believe that those later "high compression" engines performed any better at sea level than their non-overcompressed counterparts, unlike what happens in the sim.

 

For sure: They had different engine designations which of course is only logical since one could house an engine cannon and the other didn’t. But I think the most important thing here is the power: Even if one had a different gearing than the other, this would only result in a different rpm and torque combination, the power would still be the same. In my simulations I assume that whatever power is produced, is matched with a proper propeller and then it does not matter what gearing is used as long as the propeller matches the torque and rpm. So if the SPAD 12 and 13 had different gearing should not affect the results by much, provided both had a matching propeller mounted.

 

However, the distinction if it was a 200 or 220 hp engine is of course important but those numbers are given in the conditions as far as I can tell. In addition, as far as I know the higher CR Hispanos did not have a knock limitation at low level like some of their German engines, meaning that the 200 or 220 hp was available a SL and was then reduced in proportion to the lowered air density as the altitude went up. At least that is what I have been assuming for the 200-220 hp Hispano so far.

[No.23_Starling]

On 9/2/2022 at 11:52 AM, Holtzauge said:

 

For sure: They had different engine designations which of course is only logical since one could house an engine cannon and the other didn’t. But I think the most important thing here is the power: Even if one had a different gearing than the other, this would only result in a different rpm and torque combination, the power would still be the same. In my simulations I assume that whatever power is produced, is matched with a proper propeller and then it does not matter what gearing is used as long as the propeller matches the torque and rpm. So if the SPAD 12 and 13 had different gearing should not affect the results by much, provided both had a matching propeller mounted.

 

However, the distinction if it was a 200 or 220 hp engine is of course important but those numbers are given in the conditions as far as I can tell. In addition, as far as I know the higher CR Hispanos did not have a knock limitation at low level like some of their German engines, meaning that the 200 or 220 hp was available a SL and was then reduced in proportion to the lowered air density as the altitude went up. At least that is what I have been assuming for the 200-220 hp Hispano so far.

Your point seems to suggest that the Connors data is closer to reality (from French official tests) and not too dissimilar to the XIII 200hp, rather than the Davilla data. That’s reassuring that the FM wouldn’t be too tough for 1C to create using the existing 200hp XIII model 

[Holtzauge]

On 9/8/2022 at 12:02 AM, US103_Rummell said:

Your point seems to suggest that the Connors data is closer to reality (from French official tests) and not too dissimilar to the XIII 200hp, rather than the Davilla data. That’s reassuring that the FM wouldn’t be too tough for 1C to create using the existing 200hp XIII model 

 

Yes, as long as you have a few data points which you can use to tune the model, then making predictions at other power levels gives good accuracy. In the case of the SPAD XIII there are at least three results that pin the speed to 213-218 Km/h and the climb time to 5 Km to 18 m 30 s - 19 m 15 s. So using this as a base and increasing weight or changing power, you can get very accurate estimates. This is why I said that the SPAD XII at 883 Kg should do about 19 m 36 s to 5Km, not 23 m 13 s. However, all this of course assumes that there is nothing "off" with the SPAD XII like inappropriate prop or that the data is an outlier. But the mix of a higher ceiling and the stated climb time of 23 m 13 s indicates to me that something is off with this data.

[No.23_Starling]

Thanks Holtz, that’s starting to make much more sense now. I’m still keen to find out where I can get access to Guynemer’s letters and writings around the plane and tests. Particularly keen to see the letters about the controls

[No.23_Starling]

All, I've come across a couple of excellent photos from the Imperial War Museum's online archive. They've digitised a lot of their collection and can thoroughly recommend a dig around. They also have a photo of the float-plane version which shared a lot of the same characteristics.

 

I've also reached out to le musée de l’Air et de l’Espace around their collections and archivists to see if any of them can point me towards any original records around the plane including Guynemer's correspondences with the designers. All I can find is secondary sources which quote the primary ones.

[No.23_Starling]

More snaps this time from Connors. Great side views of the wing stagger plus technical drawings showing the wing modifications and the different windscreen vs Spad VII