Fokker D.VIII (FC2 vs. RoF)

[Avimimus]

The 3d model has a lot of improvements (rather stunning actually)... and the damage model is also much improved.

 

As for the FM: It seems quite a bit more stable under some circumstances, and the roll rate feels like it is less than in RoF... seems to have been significantly reworked? How are you all finding the flight model? Definitely worth checking out.

[US103_Baer]

1 hour ago, Avimimus said:

... and the damage model is also much improved.

 

 

Specifics? PvP?

[US41_Winslow]

You can shoot its wings off with a under a few hundred rounds against the A.I.  It seems somewhere around the Dr.I in terms of wing strength and not at all indestructible like the D.VII.

[NO.20_W_M_Thomson]

You can chop trees down with the wings, prop hangs like a helicopter, turns on a dime. climbs pretty good. Good time to be a German pilot.

 

[Avimimus]

30 minutes ago, US28_Baer said:

Specifics? PvP?

 

Compared to Rise of Flight... it still lacks the modelling of every bracing wire and wing rib that some people demand (and everyone would like)... but it does obviously benefit from having the new bullet-hole decals, the overall stronger wings, the improved ballistic calculations etc. that all FC1/FC2 aircraft have.

[1PL-Husar-1Esk]

Does ROF D8 FMs was changed in December 2014 patch ? If so it would be hard to compare because they said that FC planes are based on previous patch FMs.

[=LD=Brazo]

3 hours ago, NO.20_W_M_Thomson said:

You can chop trees down with the wings, prop hangs like a helicopter, turns on a dime. climbs pretty good. Good time to be a German pilot.

 

I flew my camel against one yesterday and they out turned me with a scary ufo like ease, we’re faster than me, seemed like a WW1.5 plane!

[BMA_Hellbender]

1 hour ago, 1PL-Husar-1Esk said:

Does ROF D8 FMs was changed in December 2014 patch ? If so it would be hard to compare because they said that FC planes are based on previous patch FMs.

 

It wasn't changed in RoF 1.034, so you can compare it to RoF directly. I see much the same minor improvements in terms of FM between RoF and FC as with other planes. Wing bullet resistance has definitely been revised. Wing G tolerance is the same as in RoF, and is very good (though not impossibly good as the Pfalz D.IIIa). In reality it would have been able to endure more G than even the Fokker D.VII, especially after the E.V structural wing failures were fixed. It's a D.VIII, after all, not an E.V.

 

I don't understand why it has higher static RPM than the Fokker Dr.I as they appear to have the exact same engine and prop — other than "we didn't nerf it". Plausible explanations are that mineral oil quality improved as the war progressed and mechanics risked higher RPMs in spite of not having access to castor oil. This will likely be the reason why the upcoming Siemens-Schuckert D.IV will not have its engine seize after some hours of service.

 

Anyway, great, fun little plane. The model looks great! Still not a sufficient reason to come back to PvP unless they put some actual work into fixing the control cables issues.

[ZachariasX]

In FC, the D.VIII and the Dr.I really seem to have the same engine. Funny enough, they both have a very early prop configuration for the Ur-2 engine, only 2.2 m pitch, when usually 2.3 m were standard, such as also being used by Chill and Mikael Carlson on their respective Dr.I.

 

However, in both cases, the engine revs high. On the Dr.I, it can do 1320 rpm at sea level, something @Chill31 is most likely reaching with having a 2.3 m prop on his *very powerful* rotary.

 

It means, the aircraft are about 4.5% too slow vs. rpm. Yet we have really high rpm, I get up to 1380 at seal level on the D.VIII, menaing that top speed of the D.VIII is probably not much off the mark.

 

It would be interesting to know (but really a bit much information for us players) what factor they used in the FM to make the Dr.I that much slower than the D.VIII.

 

Sea level, I get 165 km/h at 1320 rpm for the Dr.I and 182 km/h at 1380 rpm for the D.VIII. (Full tank in both cases.)

 

The in-game Dr.I could do theoretically 174 km/h at recorded revs.

The in-game D.VIII could do theoretically 182 km/h at recorded revs.

 

This means that the Dr.I has LOTS of airframe drag in the game and makes it fall short 9 km/h. That is a slip of ~5%, and that is a lot, something you hardly get by flying at low cruise rpm on a fixed pitch GA. On a 172, the slip varies between <1% at 2400 rpm (for the 7557 prop) and ~3% at 2100 rpm (all at 2000 ft.pressure altitude). It is also of note that Chills Dr.I follows prop pitch on the spot at given airspeeds.

 

We can see that even though the real Dr.I has almost no slip at full power (very comparable to a Cessna 172), it  has a ton of slip in our game. I think it is actually that draggy, that it starts to work against prop rpm, reducing the 1380 rpm of what the plane would have to 1320.

 

Personally, at this point I don't think our Dr.I is all there yet, as there is definitely something weird going on to make it as slow as it is. My hypothesis is that it should have way less drag, but (as most WW1 birds) way more induced drag. It would make the plane almost as fast at sea level as the Dr.I and bring it much closer to competition, but at altitude it would start to suffer a lot, and this is where the D.VIII shines by design. It should probably offset somewhat the performance gap between the much higher powered SEs and SPADs.

 

But still, what we have now is a very nice D.VIII that in terms of airspeed in some way is probably not far from what it should do. The 5 % we are lacking in prop pitch, we get by "overrevving" the engine. As a bottom line for gaming in FC, the D.VIII looks ok. Maybe @Holtzauge at some point can do a simulation of what it can be expected to do at various altitudes.

 

About the propeller, I speculate that the 2.3 m pitch prop should be standard as it was commonly used. Also I doubt that people back then would fly at revs greather then 1300 rpm when that is even the limit to where Chill would push his superior rotary. Unfortunately, I could not read the marking on the only all original D.VIII airframe I've ever came across, at the Caproni Museum in Italy. I had to climb the cordon to see underneath and I wouldn't do that.

 

 

Also, engines and propellers mounted to museum exhibits often are not original, they use what they have "to put something on" if the original is lacking and that often is not mentioned in the description of the exhibits.

 

24 minutes ago, =IRFC=Hellbender said:

it has higher static RPM

How do you get static RPM in FC? There's no brakes. Taxi to a hill and...?

Edited June 2, 2021 by ZachariasX

[J2_Trupobaw]

24 minutes ago, =IRFC=Hellbender said:

 

I don't understand why it has higher static RPM than the Fokker Dr.I as they appear to have the exact same engine and prop — other than "we didn't nerf it". Plausible explanations are that mineral oil quality improved as the war progressed and mechanics risked higher RPMs in spite of not having access to castor oil. This will likely be the reason why the upcoming Siemens-Schuckert D.IV will not have its engine seize after some hours of service.

 

Less drag for engine to overcome?

[BMA_Hellbender]

17 minutes ago, ZachariasX said:

How do you get static RPM in FC? There's no brakes. Taxi to a hill and...?

 

Basically. Or land in deep muddy terrain and use full positive elevator deflection. The Fokker Dr.I gets about 50 less RPM. So unless they have a different prop pitch, the UR.II on the Dr.I simply has a lower limit set.

 

It's all mental gymnastics, obviously, we know what happened with the Dr.I in RoF 1.034 and we know how it performed before that (top speed 178km/h at the same RPM as the Fokker D.VIII).

 

  

11 minutes ago, J2_Trupobaw said:

Less drag for engine to overcome?

 

Static RPM.

 

That is: max engine RPM while not moving (through the air) on the ground. The airframe it's attached to makes no difference at that point.

 

Edited June 2, 2021 by =IRFC=Hellbender

[J2_Trupobaw]

That'll be 2014 engine change, then; it did adjust plane performance by removing RPM.

 

Plausible explanation is that in timeframe where two planes coexist and can be compared, Dr.I is old specimen worn down from six+ months of fighting and D.VIII is brand new. 

 

[BMA_Hellbender]

13 minutes ago, J2_Trupobaw said:

That'll be 2014 engine change, then; it did adjust plane performance by removing RPM.

 

Plausible explanation is that in timeframe where two planes coexist and can be compared, Dr.I is old specimen worn down from six+ months of fighting and D.VIII is brand new. 

 

Yup. Or Voltol quality improved, or more engine overhauls were performed later in the war hence higher RPM could be attained and risked. Why we then have late 1918 parachutes on a Fokker Dr.I with a mid-1918 engine is another can of worms.

 

It does settle the argument whether or not planes use the same engine with the same factory fresh conditions. They don’t.

 

What the Sopwith Triplane’s static RPM will be compared to the Sopwith Camel is hence anyone’s guess.

[ZachariasX]

1 hour ago, =IRFC=Hellbender said:

It's all mental gymnastics, obviously, we know what happened with the Dr.I in RoF 1.034 and we know how it performed before that (top speed 178km/h at the same RPM as the Fokker D.VIII).

Actually, I don't really know what happened over this time. "The Patch" has it just reduced engine power? Here, there is more at play. The aircraft are all so slow that airframe drag is about the same for practical purposes in all aircraft and the top speed is not limited by drag in any aircraft, but by rpm x propeller pitch. The aircraft hence vary more in free energy at given state than top speed. The free energy then decides how fast it can tun in sustained manner of how fast it can climb.

 

I don't think it is suitable to just compare top speeds (top speed is obvious, even though may don't want to see that), as it masks the difference of the airframes. For instance the Pfalz D.VIII and the SS D.IV are identical aircraft, same angine, same dimensions. but the SS D.IV flies circles around the Pfalz for the simple reason that it has much less induced drag. Hence it tuns better, climbs better and it faster at altitude.

 

That the Dr.I has such an excessive airframe drag is rather new to me and it makes no sense in regard to th e real aircraft. It also has never been mentioned regarding "The Patch". It is drag and not not induced drag, as full bore at low altitude, induced drag adds less than it would at altitude, where power drops and AoA rises. In FC however, going higher actually closes the gap between the D.VIII and the Dr.I, from 17 km/h at sea level to 9 km/h at 6000 m. It should be the other way around, they should be almost equally fast down low, but higher up, the D.VIII should be getting progressively faster than the Dr.I. But in the game, drag reduction by thinning of the air makes the Dr.I go faster.

 

I think, in it's own way the D.VIII that we were given is a suitable toy for play, but the Dr.I is really off.

[Cynic_Al]

1 hour ago, =IRFC=Hellbender said:

Basically. Or land in deep muddy terrain and use full positive elevator deflection. The Fokker Dr.I gets about 50 less RPM. So unless they have a different prop pitch, the UR.II on the Dr.I simply has a lower limit set.

 

............................................................

 

Static RPM.

 

That is: max engine RPM while not moving (through the air) on the ground. The airframe it's attached to makes no difference at that point.

 

Put a Dr1 into a reasonable climbing attitude and you may see 1200 RPM; bring it into a stall/prop-hanging attitude and magically the RPM rises.  Were I to theorise as to the reason for that, someone would likely turn it into an allegation, so I wont, but that 'characteristic' makes an absolute mockery of any interpretation of static RPM.

[Holtzauge]

While the Fokker Dr.1 and D.VIII had the same engine and propeller diameter, the Dr.1 had a 2.3 m pitch propeller and the D.VIII had a 2.6 m pitch as far as I know. This would imply that the D.VIII IRL had lower rpm's across the board, i.e. lower in static, climb and high speed conditions so if you are getting such high rpm's in-game with a 2.2 m pitch prop and if the Dr.1 is revving lower than the D.VIII this sounds strange.......

 

So how does the Fokker D.VIII compare to the Nieuport 28 in-game when it comes to turns? Anyone tried that in MP taking the machines to the edge? Which one wins and how big is the margin?

[BMA_Hellbender]

Just now, Holtzauge said:

So how does the Fokker D.VIII compare to the Nieuport 28 in-game when it comes to turns? Anyone tried that in MP taking the machines to the edge? Which one wins and how big is the margin?

 

IIRC, the Fokker D.VIII and Sopwith Dolphin have near-identical sustained turn: slightly worse than the Albatros D.Va, slightly better than the Fokker D.VII. In the ballpark of 9.5-10 seconds. I'll check tonight.

[ZachariasX]

34 minutes ago, Holtzauge said:

the Dr.1 had a 2.3 m pitch propeller and the D.VIII had a 2.6 m pitch as far as I know.

There is this report about the D.VIII:

 

 

 

The 110 Oberursel was stated to produce 137 hp at 1390 rpm. So at least  in theory the engine could rev beyond 1300 rpm. This would give it about 118 hp at 1200 rpm and I think this puts it in line with Chills engine, at least in terms of volumetric efficiency.

 

The Propeller being an Axial 01476. Anyone has the dimensions? They say it is indeed a D260/P260 propeller in this report.

 

 

This may be of interest:

 

PILOTS OBSERVATIONS

The airplane has a tendency to turn to the right in taxying, takes off very quickly, climbs very rapidly, and is very maneuverable.
It is very easy to fly, and the controls are sensitive. It is tail heavy, but so light on the controls that it is not tiresome to fly.
The visibility is very good.
The machine guns are placed that in the event of a crash, the pilot would undoubtedly be injured by being thrown against the same.
The airplane lands very slowly with a slight tendency to drop the right wing, and to turn to the right on the ground.
The controls for the engine are very inconveniently located, inasmuch as the throttle for the gas is on the left of the fuselage, and the throttle for the air is on the left side of the control stick.

 

(Emphasis mine)

 

Further from this report:

 

 

We know that this real Fokker D.VIII did 115 mph on the deck, 185 km/h respectively. In game, we have 182 km/h or so, hence apart from internal nitpicking, the devs really deilvered and for gaming purposes we are not really off the mark. 110 mph (177 km/h) or so at 4000 m according to chart and we have about 180 km/h in game.

 

I'm rather happy with the D.VIII regarding level flight speeds. It is as if the devs matched the D.VIII against this readily avauilable test (which is plausible) without actually changing its odd "gearing".

 

 

[=IRFC=Gardimus]

6 hours ago, Brazo said:

I flew my camel against one yesterday and they out turned me with a scary ufo like ease, we’re faster than me, seemed like a WW1.5 plane!

 

When testing it out yesterday with other players, I found the camel out turns it. Add a bit of climb to that turn and the D8 will need to find a different solution to get guns on you. 

 

Camel was a little faster(~1kt) at sea level but maybe it was a mixture thing. 

 

Seems to be an effective plane without being a game breaker. If I had to choose the Dr1 or D8 to fight a camel, I would take the Dr1. 

[NO.20_Krispy_Duck]

I think the D.VIIF is the bigger threat still, but the D.VIII in FC is a solid turn fighter for someone who wants something that still has a fair amount of stability. It prop hangs rather nicely and will loop in-place without needing much entry dive at all. The Camel seems to turn slightly faster, but the D.VIII seems much less inclined to wash out of the turn and spin. It seems like a good option if you want a "turn fighter" but want a little more stability than the Camel or Dr.1. I think the expert turn fighting players will stick with the Camel or Dr.1 for now, but the D.VIII is an option at least, especially if you tend to over-reach and spin in the other planes.

 

I rolled the plane firmly up on its side during landing with no damage to the wing or aileron. I wouldn't call the plane "unbreakable", but it's not terribly prone to crushing its wing either. I didn't count the number of bullets it took to bring down. It seemed less than the D.VIIF to me, but that's a guess.

 

If you attack one, I'd say hit-and-run from altitude in everything except the Camel. The Camel can turn fight it if you know the Camel well enough. But it's not going to be a pushover to beat in a turn. I guess that's kind of par for the course though.

Edited June 2, 2021 by NO.20_Krispy_Duck

[Cynic_Al]

6 hours ago, =IRFC=Hellbender said:

This will likely be the reason why the upcoming Siemens-Schuckert D.IV will not have its engine seize after some hours of service.

 

When would it exist long enough for that to happen?

[Holtzauge]

@ZachariasX: Thanks: I could not find the reference for the 2.6 m pitch prop initially but as that report states, the propeller used was an Axial Edelzug serial No 16065 marked D 260 St 260 and as the tables says, even with this coarser pitch propeller they got 1202 rpm in climb and 1390 rpm at a top speed of 115 mph at SL.

 

So while the US Fokker D.VIII test was run with at 2.6 m diameter propeller just like on Chill’s and Mikael Carlson’s Dr.1’s, the D.VIII in this test had a 2.6 m pitch compared to the 2.3 m pitch they have which without a doubt means higher revs just like Chill has been reporting.

[=LD=Brazo]

57 minutes ago, Gardimus said:

 

When testing it out yesterday with other players, I found the camel out turns it. Add a bit of climb to that turn and the D8 will need to find a different solution to get guns on you. 

 

Camel was a little faster(~1kt) at sea level but maybe it was a mixture thing. 

 

Seems to be an effective plane without being a game breaker. If I had to choose the Dr1 or D8 to fight a camel, I would take the Dr1. 

Could just be me then but I was going for it! It did seem ufo like but I wasn’t playing on our usual server so things could have been different? 

Edited June 2, 2021 by Brazo

[ZachariasX]

11 minutes ago, Holtzauge said:

1390 rpm at a top speed of 115 mph at SL

I find this odd. If that were the case, it must do 135 (!) mph instead of 115, or the propeller would be terribly, terribly inefficient. Now way it would be good in climb if it would so inefficient.

 

Looking at the numbers, I think they made an error in this report or in transcribing the report. The plane can only go 115 mph @1390 rpm if fitted with an 2.3 meter pitch prop. I would have to have an alternative documentation for this Axial propeller mentioned in the report.

 

EDIT: Actually, it only makes sense with a 2.2 m prop, the report is almost spot on on what we have in the game.

Edited June 2, 2021 by ZachariasX

[Holtzauge]

11 minutes ago, ZachariasX said:

I find this odd. If that were the case, it must do 135 (!) mph instead of 115, or the propeller would be terribly, terribly inefficient. Now way it would be good in climb if it would so inefficient.

 

Looking at the numbers, I think they made an error in this report or in transcribing the report. The plane can only go 115 mph @1390 rpm if fitted with an 2.3 meter pitch prop. I would have to have an alternative documentation for this Axial propeller mentioned in the report.

 

EDIT: Actually, it only makes sense with a 2.2 m prop, the report is almost spot on on what we have in the game.

 

Well in my simulations I get around 115 mph for both the Fokker D.VIII and the Clerget powered Sopwith Camel at SL. So what is your SL estimate for the Sopwith Camel with a 2.59 m diameter and 2.65 m pitch prop?

[ZachariasX]

Just now, Holtzauge said:

 

Well in my simulations I get around 115 mph for both the Fokker D.VIII and the Clerget powered Sopwith Camel at SL. So what is your SL estimate for the Sopwith Camel with a 2.59 m diameter and 2.65 m pitch prop?

With a 2.6 m pitch prop it must do 135 mph at 1390 rpm. Way off from the 115.

 

1390/60*2.2*3.6 = 183.5 [kmh] -> 115 mph

 

1390/60*2.6*3.6 = 216.8 [km/h] -> 135 mph

 

You can see that sea level speeds can only be reconcilded with a 2.2 or 2.3 m pitch prop. Any coarser prop will be very inefficient to reach only stated flight speeds. As you get the 115 mph for the Camel with a ~2.4 meter pich camel prop, then it is because you let your hypotetical Camel run at far lower rpm, I guess around 1250 rpm

 

1200/60*2.6*3.6 = 187 [km/h] -> 117 mph

Your simulation follows this simple theory as well, if you get 115 that is very much what is to be expected.

 

I definitely think they have a different propeller than stated in the D.VIII report, but the game reproduces the report almost spot on.

 

Regarding the game, if the Dr.I has indeed less static rpm, then this would only explain part of its shortcoming in speed and not being consistent with the D.VIII. Chills Dr.I as well as the Dr.I in your simulation has no problem "following" the propeller. The in game Dr.I lags the propeller (the same virtual one as on the D.VIII) by 9 km/h. I can only explain this with excessive airframe drag.

[Holtzauge]

24 minutes ago, ZachariasX said:

With a 2.6 m pitch prop it must do 135 mph at 1390 rpm. Way off from the 115.

 

1390/60*2.2*3.6 = 183.5 [kmh] -> 115 mph

 

1390/60*2.6*3.6 = 216.8 [km/h] -> 135 mph

 

You can see that sea level speeds can only be reconcilded with a 2.2 or 2.3 m pitch prop. Any coarser prop will be very inefficient to reach only stated flight speeds. As you get the 115 mph for the Camel with a ~2.4 meter pich camel prop, then it is because you let your hypotetical Camel run at far lower rpm, I guess around 1250 rpm

 

1200/60*2.6*3.6 = 187 [km/h] -> 117 mph

Your simulation follows this simple theory as well, if you get 115 that is very much what is to be expected.

 

I definitely think they have a different propeller than stated in the D.VIII report, but the game reproduces the report almost spot on.

 

Regarding the game, if the Dr.I has indeed less static rpm, then this would only explain part of its shortcoming in speed and not being consistent with the D.VIII. Chills Dr.I as well as the Dr.I in your simulation has no problem "following" the propeller. The in game Dr.I lags the propeller (the same virtual one as on the D.VIII) by 9 km/h. I can only explain this with excessive airframe drag.

 

Yes, but the Clerget and Le Rhone are both rated at 1250 rpm and according to Air Board data the Clerget powered one does 113 mph at SL so I would expect to see a table similar to the one we have for the Fokker D.VIII trial at slightly lower than rated rpm in climb at substantially higher at top speed and not 1165 rpm (calculated as per your method above) if we had one. If it (the Camel) really did 1165 rpm at 113 mph (i.e. 85 rpm under rated rpm) then the rpm in climb would be very low I think.

 

Most data I’ve seen where we have actual rpm values for climb and top speeds usually either straddle rated rpm in climb and high speed conditions or, are close to rated rpm in climb and substantially higher at top speed, just like we also see in game.

 

In addition, look at the data in the USAS report 1669 on the Fokker D.VIII:

 

“PROPELLER.
Make: Edulzug Axial
Number of blades: 2.
Diameter: 260 m/m or 10.21'.
Tips: Not tipped.
Manufacturer's No.: 16065.
Remarks: 16065 110 P.S. LeRhone D 260, St 260 TO”

 

That last line giving manufacturers serial number, intended engine, diameter and pitch which was commonly done on propellers at the time so  the “St 260” does not look like a transcription error to me.

[1PL-Husar-1Esk]

I posted this on beta forums.

Both Fokker Dr.I and Fokker D.VIII share the same engine Oberursel UR II rotary 9 cyl 110 HP 

But there is significant difference in engine RPMs between them.

 

map Kuban autumn 300m

 

Fokker Dr.I RMPs goes max to 1340

Fokker D.VIII RMPs  goes  max to 1380

this 40 RPMs difference is significant as power and speed highly depends on it.

 

 

[ZachariasX]

29 minutes ago, Holtzauge said:

That last line giving manufacturers serial number, intended engine, diameter and pitch which was commonly done on propellers at the time so  the “St 260” does not look like a transcription error to me.

It's still odd. The Camel has an engine that is at least as strong as the D.VIII, but it reaches much less revs, *but this at the same speed* than the D.VIII, while having for practical purposes the same propeller. Yet the D.VIII that reaches considerably higher revs is not one jota faster than the lower revving Camel. If I had to choose an aircraft between the two that has less  drag in any way, that it would be the D.VIII. That one should be faster. But in fact it is much lower performing that the camel, given it has more power at hand yet only reaches a similar airspeed.

 

There is something odd here. it just doesn't add up for me.

 

 

4 minutes ago, 1PL-Husar-1Esk said:

this 40 RPMs difference is significant as power and speed highly depends on it.

You know, when I saw that initiall, i thought that is due to the Dr.I being considerably slower than the D.VIII. The higher the AoA of the prop blades, the more force it needs to crank it. The Dr.I being 9 km/h slower might cause such an effect, but I am still surpriseed to find such an effect at flight speeds. Real proof you have by making a static run, as Bender did. He says the D.VIII gets higher static runs, hence, it must have more power.

 

To me it seems the devs indeed took the same engine layout from the Dr.I and just added a little more *oomph* to make it fit the report I posted above. But this is just speculation.

Edited June 2, 2021 by ZachariasX

[Holtzauge]

1 minute ago, ZachariasX said:

It's still odd. The Camel has an engine that is at least as strong as the D.VIII, but it reaches much less revs, *but this at the same speed* than the D.VIII, while having for practical purposes the same propeller. Yet the D.VIII that reaches considerably higher revs is not one jota faster than the lower revving Camel. If I had to choose an aircraft between the two that has less  drag in any way, that it would be the D.VIII. That one should be faster. But in fact it is much lower performing that the camel, given it has more power at hand yet only reaches a similar airspeed.

 

There is something odd here. it just doesn't add up for me.

 

Yes, I agree in some sense it seems strange and while the rpm/pitch formula in many cases produces good results, maybe it cannot predict well in all cases?

 

I had another look at the report below which we discussed a while back and found some interesting results:

 

 

 

The first thing I note here is that just as what you would expect from a propeller that is well matched to the engine, the rpm in climb is below while the rpm at high speed is above the Le Rhone 80 hp rated rpm which is 1200.

 

So according to the table, the Thomas Morse S-6 does 97 mph at 1260 rpm at SL with a 90.5“ pitch (2.3 m) propeller.

 

Using the rpm/pitch calculation formula to derive speed this gives:

 

V=1260/60*2.3*3.6=174 Km/h or 108 mph so substantially faster than the 97 mph is the table.

 

So while the method can produce good estimates in some cases, it seems it does not always get it right?

 

[ZachariasX]

1 hour ago, Holtzauge said:

So while the method can produce good estimates in some cases, it seems it does not always get it right?

It is not only not right, it is prone to make errors. But I would expect deviations to be systemic. And the error can be quantified. And that is key.

 

The rule of the thumb that I have on deviation of the results is it indicates a daviation of an optimal setting.

 

What I look at tables for aircraft, then (in case of suitably selected propellers), at suitable maximum power setting, the propeller almost matches aerodynamic pitch. The more you lower rpm, the larger the slip becomes.

 

In a Cessna, you can open the manual and the slip is  <1% at high revs to ~4% at enonomy cruise.

 

Conversely, if I get a large slip at full power, this indicates to me that the engine is not living up to the propellers requirement. The airplane is "overpropped" to say. If I reach almost zero slip below max rpm, then this would indicate that the plane is "underpropped", the engine too strong.

 

Now regarding the Test above, the Morse is indeed slow in this test. But guess what when Chill puts that very engine/prop combo on his Dr.I? he has almost no slip and attains about the same flight speed per revs as he does with the 120 hp, featuring an equally steep propeller. This tells me that Chill has a great 80 hp engine, as it was envisioned when putting the Morse prop on it. And I suspect the engine in the test above not being of that quality.

 

EDIT: I might add that in the test above I would indeed make a question mark to the actual speeds. The formula I am using is rather useful as a crosschecking tool after having substancial reference examples at hand, and in this test, mumbers come out weird, without further explanation other than the Morse Scout being an inherently awful design. My take is, if other, similar types behave in a way, then I need a good explanation for another to deviate from the general trend. And If Chills Dr.I can match the propeller, then why oh why wouldn't the Morse? That's almost 10 mph wotrh of added drag, at 100 mph, a speed where a piano is aerodynamic enogh.

 

Edited June 2, 2021 by ZachariasX

[Holtzauge]

51 minutes ago, ZachariasX said:

It is not only not right, it is prone to make errors. But I would expect deviations to be systemic. And the error can be quantified. And that is key.

 

The rule of the thumb that I have on deviation of the results is it indicates a daviation of an optimal setting.

 

What I look at tables for aircraft, then (in case of suitably selected propellers), at suitable maximum power setting, the propeller almost matches aerodynamic pitch. The more you lower rpm, the larger the slip becomes.

 

In a Cessna, you can open the manual and the slip is  <1% at high revs to ~4% at enonomy cruise.

 

Conversely, if I get a large slip at full power, this indicates to me that the engine is not living up to the propellers requirement. The airplane is "overpropped" to say. If I reach almost zero slip below max rpm, then this would indicate that the plane is "underpropped", the engine too strong.

 

Now regarding the Test above, the Morse is indeed slow in this test. But guess what when Chill puts that very engine/prop combo on his Dr.I? he has almost no slip and attains about the same flight speed per revs as he does with the 120 hp, featuring an equally steep propeller. This tells me that Chill has a great 80 hp engine, as it was envisioned when putting the Morse prop on it. And I suspect the engine in the test above not being of that quality.

 

Yes, the calculation seems to work well in some cases for some particular engine/prop/rpm/diameter combinations but thinking some more about it I’m not sure how well it handles the general case: Consider two propellers revolving at the same rpm. One has a big diameter but small pitch. The other smaller diameter but larger pitch. Now the pitch/rpm method would predict different speeds if these two props are mounted on the same airplane. However, thrust is the product of air mass flow and speed imparted to the flow and does not care if a larger amount of air mass flow is given a slower speed (large dia small pitch prop) or if a lesser mass flow is given a higher velocity (smaller dia larger pitch prop).

[ZachariasX]

33 minutes ago, Holtzauge said:

I’m not sure how well it handles the general case:

On that we agree. I just thing something is wrong when I am comparing near identical aircraft. Essentially, deviations there would serve as indication as to where dig deeper.

[Holtzauge]

Will be interesting to see what results @=IRFC=Hellbender comes up with in the turn comparison to the Nieuport 28 but when I tried in QM I got the impression that the Fokker D.VIII turned better than the Nieuport 28 which is not what I see in the simulations. Could of course be some AI issue but it definitely felt easier in a QM to follow the Nieuport when sitting in the Fokker than the other way around. At least for me.

[Cynic_Al]

3 hours ago, Holtzauge said:

when I tried in QM I got the impression that the Fokker D.VIII turned better than the Nieuport 28 which is not what I see in the simulations. Could of course be some AI issue but it definitely felt easier in a QM to follow the Nieuport when sitting in the Fokker than the other way around.

 

Didn't you read the recent debate on the N28?  It's never going to out-turn anything.  One day we'll get to the bottom of it, even though at that point it probably won't do us any good, but at least we'll know.

[BMA_Hellbender]

11 hours ago, Holtzauge said:

Will be interesting to see what results @=IRFC=Hellbender comes up with in the turn comparison to the Nieuport 28 but when I tried in QM I got the impression that the Fokker D.VIII turned better than the Nieuport 28 which is not what I see in the simulations. Could of course be some AI issue but it definitely felt easier in a QM to follow the Nieuport when sitting in the Fokker than the other way around. At least for me.

 

I did some measurements again and came to some very surprising results.

 

From best to worst at 50m ASL flown with 10-20l of fuel, empty ammo, 60 degree bank (2g):

 

• Albatros D.Va: 9s @ 120km/h
   
• Fokker D.7F (full altitude throttle): 9.5s @ 100-110km/h
   
• Sopwith Dolphin: 10s @ 120km/h
   
• Fokker D.8: 10.5s @ 100km/h
   
• Nieuport 28: 11s @ 140km/h
   
• Fokker D.7: 11.5s @ 100-110km/h
   

What jumps out immediately is the significantly smaller turn radius (lower speed for best sustained turn) with all the Fokkers. With both the D.7 and D.7F it is almost impossible to determine when you have reached your ideal speed for best rate of turn through visual or force feedback. Pull a little bit too hard and your turn rate will worsen without any significant adverse effects (no wing buffeting or loss of altitude, for example), all the while still lowering your speed and hence improving your turn radius, until you eventually reach stall speed and roll out of the turn. In other words: you're prophanging around. Not really that surprising with this plane, but it does explain why I'm consistently able to outturn 7Fs in a Dolphin: pilots are likely not using full altitude throttle at sea level and/or pulling too hard.

 

The Nieuport 28 with its incorrectly high stall speed (~85km/h instead of ~75km/h) obviously suffers the most from large turn radius, as bank angle increases stall speed increases as a function of the square root of the load factor, or 1.4 times level flight stall speed at 2g. Much like the Dolphin and D.Va it should really be able to hold a 2g sustained turn at 120km/h, and have a better turn rate to boot.

 

Finally the Fokker D.8 is easy enough to find its best turn radius, it's exactly when wing buffeting starts. In practice it feels just about equal to the Dolphin in a turnfight, aided by its smaller turn radius and better climb.

 

Edited June 3, 2021 by =IRFC=Hellbender

[Holtzauge]

9 hours ago, =IRFC=Hellbender said:

 

I did some measurements again and came to some very surprising results.

 

From best to worst at 50m ASL flown with 10-20l of fuel, empty ammo, 60 degree bank (2g):

 

• Albatros D.Va: 9s @ 120km/h
   
• Fokker D.7F (full altitude throttle): 9.5s @ 100-110km/h
   
• Sopwith Dolphin: 10s @ 120km/h
   
• Fokker D.8: 10.5s @ 100km/h
   
• Nieuport 28: 11s @ 140km/h
   
• Fokker D.7: 11.5s @ 100-110km/h
   

What jumps out immediately is the significantly smaller turn radius (lower speed for best sustained turn) with all the Fokkers. With both the D.7 and D.7F it is almost impossible to determine when you have reached your ideal speed for best rate of turn through visual or force feedback. Pull a little bit too hard and your turn rate will worsen without any significant adverse effects (no wing buffeting or loss of altitude, for example), all the while still lowering your speed and hence improving your turn radius, until you eventually reach stall speed and roll out of the turn. In other words: you're prophanging around. Not really that surprising with this plane, but it does explain why I'm consistently able to outturn 7Fs in a Dolphin: pilots are likely not using full altitude throttle at sea level and/or pulling too hard.

 

The Nieuport 28 with its incorrectly high stall speed (~85km/h instead of ~75km/h) obviously suffers the most from large turn radius, as bank angle increases stall speed increases as a function of the square root of the load factor, or 1.4 times level flight stall speed at 2g. Much like the Dolphin and D.Va it should really be able to hold a 2g sustained turn at 120km/h, and have a better turn rate to boot.

 

Finally the Fokker D.8 is easy enough to find its best turn radius, it's exactly when wing buffeting starts. In practice it feels just about equal to the Dolphin in a turnfight, aided by its smaller turn radius and better climb.

 

 

Interesting and thanks for doing the trials @=IRFC=Hellbender!

 

Adding to the points you already made about the relative turn performance between the scouts, what also sticks out in the test results above is how good the Albatros D.Va is in-game: If the Nieuport 28 sticks out in being so bad compared to IRL, then the Albatros is the exact opposite, it performs much better in-game  than one would expect from the IRL specifications. It even beats the Fokker D.VIIF!

 

I guess one can theorize on why this is so but the WW2 parts of BoX has made great strides during the past 5 years and many turn performance FM’s for WW2 era aircraft are now quite close to IRL specifications. However, AFAIK the Albatros FM stems from very early RoF development and maybe that particular FM is getting particularly long in the tooth?

 

In addition, before making any calls of which way this sim seems to be going in terms of WW1 scout FM’s, I was waiting on the Fokker D.VIII to see how that came out and now that we have the results it looks a bit bleak because the Nieuport 28 should beat the Fokker D.VIII in turn handily but it looks like the FC FM’s are going to be a repeat of the models that were developed in RoF and TBH I was hoping that the FC WW1 FM’s would be revised and brought up to BoX WW2 aircraft standards.......

 

Edited June 3, 2021 by Holtzauge

[BMA_Hellbender]

2 hours ago, Holtzauge said:

In addition, before making any calls of which way this sim seems to be going in terms of WW1 scout FM’s, I was waiting on the Fokker D.VIII to see how that came out and now that we have the results it looks a bit bleak because the Nieuport 28 should beat the Fokker D.VIII in turn handily but it looks like the FC FM’s are going to be a repeat of the models that were developed in RoF and TBH I was hoping that the FC WW1 FM’s would be revised and brought up to BoX WW2 aircraft standards.......

 

Now that the Snipe and Siemens-Schuckert are announced, which I bloody well expect will be built entirely up to BoX standards with accurate spin recovery and everything, it's primarily a DM revision that is needed to bring multiplayer back to life. From the existing FC1 and FC2 planeset we can salvage a few late war planes (VIIF, DXII, F2B F.III, S.E.5a, HP O-400) to have a "Rise of Flight 1919" Arras front dogfighting experience. I think that's the best we can still hope for and it might be a fun gameplay loop for some time to come, with the other "legacy" planes thrown in as oddities. I must admit that I'm no longer excited about FC3 or even a hypothetical Hanriot HD.1, nor how they will make it all fit into the existing modules with parachutes on some 1917 planes etc, or how multiplayer should be divided over several modules and time periods. It's a bit of a mess, much the same problem as with the BoX modules, where everyone just flies whatever is new and best.

[Holtzauge]

21 hours ago, ZachariasX said:

EDIT: I might add that in the test above I would indeed make a question mark to the actual speeds. The formula I am using is rather useful as a crosschecking tool after having substancial reference examples at hand, and in this test, mumbers come out weird, without further explanation other than the Morse Scout being an inherently awful design. My take is, if other, similar types behave in a way, then I need a good explanation for another to deviate from the general trend. And If Chills Dr.I can match the propeller, then why oh why wouldn't the Morse? That's almost 10 mph wotrh of added drag, at 100 mph, a speed where a piano is aerodynamic enogh.

 

 

I saw you made an edit @ZachariasX and I found some new info as  well:

 

I just found a couple of French tests for captured Albatros D.Va:

 

Test 1: SL top speed 172 Km/h with 2.75 m dia 1.97 m pitch propeller at 1500 rpm.

 

Test 2: SL top speed 171 Km/h with 2.8 m dia 1.795 m pitch propeller at 1555 rpm.

 

I think this also fits the momentum theory idea well: Both these aircraft are almost identical in speed: 171 versus 172 Km/h but one attains the speed by using a larger diameter propeller with lower pitch and the other one a smaller diameter propeller with a larger pitch.

 

However, if we use the rpm/pitch method to predict speed:

 

1500/60*1.97*3.6=177 Km/h

 

1555/60*1.795*3.6=167 Km/h

 

So in one case positive and in the other negative “slip”……..

 

If we now instead put on a theoretical prop in between those two diameters and pitches then we would probably be right on the money so for some diameter and pitch combinations the method seems to work well and for others it doesn't. I think this is why you see such good correlations in some cases, e.g. for the Dr.1 and why it does not work out so well in others like for the Morse and the D.VIII.

[Holtzauge]

4 hours ago, =IRFC=Hellbender said:

 

Now that the Snipe and Siemens-Schuckert are announced, which I bloody well expect will be built entirely up to BoX standards with accurate spin recovery and everything, it's primarily a DM revision that is needed to bring multiplayer back to life. From the existing FC1 and FC2 planeset we can salvage a few late war planes (VIIF, DXII, F2B F.III, S.E.5a, HP O-400) to have a "Rise of Flight 1919" Arras front dogfighting experience. I think that's the best we can still hope for and it might be a fun gameplay loop for some time to come, with the other "legacy" planes thrown in as oddities. I must admit that I'm no longer excited about FC3 or even a hypothetical Hanriot HD.1, nor how they will make it all fit into the existing modules with parachutes on some 1917 planes etc, or how multiplayer should be divided over several modules and time periods. It's a bit of a mess, much the same problem as with the BoX modules, where everyone just flies whatever is new and best.

 

Yes, I think in the long run there is no way around that questionable FM's from the origins of RoF need to be revisited in FC: How else do you add new aircraft? Do you add them as they performed historically or to be correct in relation to the older legacy RoF FM's?

 

If the latter then how should the Snipe and SS D.IV be done? In relation to the under performing Nieuport 28 or the over performing Albatros D.Va? Of course the only sensible way in the long run is to add new planes with as historically correct FM's as possible but then very important aircraft like for example the Albatros D.Va and S.E.5a will not be correct in relation to the new additions.

 

In addition, I just saw the change in your sig with the strike through text in Hanriot with reference to the DM (Serious stuff that!) and I can only agree: The long term survival of FC with the "hard core" simmers rests in getting the DM right.

 

For as Cato the Censor (234–149 BC) so wisely puts it in his speeches: "Furthermore, I consider that Carthage the old DM must be destroyed"