Will they model the climbing prop or the straight and level prop? Or maybe both and introduce the first variable pitch propeller .

.... your kidding, right?

I agree about the H&S changes often forced on replica builders but the memorial flight aircraft do seem to be quite close to original. I'm not sure I'd consider max level speed flying the aircraft to its limits, diving hard yes, not flying level.

The McCook's field test of a Fokker D.VIII with a Ur.II engine did record the following data:

----------------- Rated --Nominal-- Max ---------------------------------
Mfg ------ Model - BHP ---- BHP --- BHP---MaxRPM -- Notes----------------

Oberursel - Ur.II ---108 ---- 108 ---- 135 - 1390 --- Aluminum pistons

(*note: I converted it from ps x 0.9863 to bhp)

So we see that max output (@msl) for the Ur.II is almost identical to that of the leRhône 9Jb.

The next "fly in the ointment" is!!! I've found that "some" reported German speed figures appear to have come from the "nominal rated RPM" figures.

They are "NOT" the MAX speed at the MAX RPM!

This is the case of the Fokker Dr.I with U.I rotary. It appears that, with this aeroengine with the lubricating oil they were using, it was not recommended they run it above 1200rpm, the nominal rated RPM. At which level it outputs around 99bhp@msl.



I still get the Fokker Dr.I with this 99bhp@msl flying at around 109-111mph. This is with an "optimal/compromise" prop. With a "climb bias" prop these figures could go down 5-10mph. (I believe we "don't know" what kind of prop was on most of the reported speed figures)

I've seen reported figures between 108-115mph.

I guess what I'm trying to say is:

1. I don't see anything wrong with these reported data, given the way the data was collected.

2. The Fokker Dr.I had more in it than these reported figures show. But it could only be used for a "VERY" short time period.

By the way there are some "CLARING" anomalies in the British Air Board data.

One of them happens to be the 118.5 mph @10,000' for the leRhône powered Camel F.1. It appears to be wildly optimistic! I prefer your figure of 116mph@6500'. It looks more in line with the other available reported data.

Anyway just some thoughts.

Respectfully Submitted,

KC

Mostly. There really were different props used for different tests. If you cherry pick the numbers you could get performance that just wasn't possible in any single flight.

My point is that "real life performance" has more variables than anybody is going to model any time soon. Tests were done under a variety of conditions and none were "Truth" with the capital "T". If it is reasonably close then that is fine.

Peter, it's not so much a campaign for a slow DR1 so much as an effort to get a correctly modelled DR1.

The temptation for developers is to beef up the DR1 and the Camel, whether by selectively using only the most optimistic data or simply beefing it up in order to meet customer expectations. While the SimHQ crowd is pretty good at keeping subjective and objective reasoning balanced, there's an awful lot of folks that will instantly proclaim the modelling wrong if they can't reproduce MvR's or Jacob's kill count with ease in the type.

Bottom line on the DR1 is pretty clear: get into a knife fight with it at one's own risk, as it's a master at it.

I think it's grand that we will (hopefully) get the in-flight recorder at the same time as the DR1 and Camel (which is similarly susceptable to an "enhanced" flight model), as of all the planes these two will probably be the most debated as far as the FM goes.

24.3.1918
"...it is slower than Albatros D.V, and therefore, of little use to sneak up on the enemy at altitudes. Low down, the triplane is extremely manoeuvrable and equal to any of the English fighters."

19.7.1918
(after a fight under 1500 m)
"When I returned to the aerodrome, I jumped into my car and drove to the site of the enemy aircraft, where we discovered the SE5 to be very new and whose American pilot had been at the front for three months and expressed astonishment at the speed of my Fokker triplane."

To finish off, Flyretired posted only part of the quote from Jacobs... the part fitting to his point of view, which I find very lowly and nonconstructive to the debate.

The forum is the place where combat (real time) flight simulator fans come to play turn based strategy combat.

Good grief!

Those were the related quotes I found in the books I referenced.

This is what I love about this forum, some people think historical disagreements give them license to make personal attacks whenever they see fit.

Lowly and nonconstructive.

Who the hell are you to judge my personal convictions!

I wasnt talking just about Dr.I, but for general replica aircrafts. Anyway I still dont believe they would run Oberursel to its max 1390RPM when it was not recommended to run it over 1200RPM and risk ruining very valuable engine.

Peter, you need to moderate your tone a bit.

More interestingly, you mention that the Dr I was much faster low down than high up. What data do you have for this? Interested to know.

Any proposal that the Dr I could reach 115 mph at sea level needs to have good evidence.

Cheers,

RD.

Not so long as one stayed in level flight!

And there's the rub. The max RPM's of an engine isn't where one ever wants to be in sustained flight, as any increase will blow it.

The important thing in a sim is relative performance. While many seem to argue over numbers, the obvious seems to be discarded. The Dr.I was very similar in top speed to the Camel. If a frontline Camel's top speed is jugded to be near 115 mph, I see no reason not to take the 115 mph as a valid number.