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Chill31

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I suspect that if Chilli31 can reliably measure the airspeed of his Dr1 to within 5% he will be more than happy. As for placing bets, I seem to recall suggesting that your pitch x RPM = TAS calculation was ok as a first order approximation, or at least a sanity check. Not an accurate predictor. Which is to say that given all the factors you actually have to take into account if you are trying to calculate airspeed, it may or may not give the same result. Betting on something where you expect the result to be both uncertain and difficult to ascertain with the necessary degree of accuracy is rather silly.

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1 minute ago, AndyJWest said:

Betting on something where you expect the result to be both uncertain and difficult to ascertain with the necessary degree of accuracy is rather silly

I agree, betting is inherently a silly thing, especially since our gut feeling is really bad when it comes to numbers. I certainly don‘t claim to be an exception here.

 

3 minutes ago, AndyJWest said:

I seem to recall suggesting that your pitch x RPM = TAS calculation was ok as a first order approximation, or at least a sanity check.

Yes, that was my reasoning. It sets a clear theoretical maximum while giving grounds to further good assumptions, this lacking other info.

 

However. The times I made the check, this rule of the thumb produced astonishingly accurate numbers. I mean, I-couldn‘t-believe-how-exact exact. Hence, in my bet using 5% margin of error, I basically went with this rule of the thumb supposedly being exact, as I consider 5% the internal margin if error in measuring TAS. I was being really silly there. Or optimistic.

 

However. If @Chill31 hits these numbers, it would be fair to say that just got a fair bit better in guessing. And that would be a nice Christmas present, right? (Even if it came to pass next year.)

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

That is  how ppl do play lottery ;)

 

Yeah. Which is why I don't. If I place bets (I rarely do) it is because I am reasonably certain of the outcome, or at least I consider the odds to be in my favour. Given that my prediction regarding ZachariasX's calculation is that It may or may not give a result somewhere roundabout where Chilli31 measures it, I can't see anyone offering me odds against me being right. 

 

6 minutes ago, ZachariasX said:

...It sets a clear theoretical maximum...

 

Only if your 'theory' makes assumptions known to be demonstrably false. I'm not going to go through all this again though, so if you want to convince yourself that you've come up with a formula which makes the pitot tube entirely redundant, feel free to do so. Just don't expect others to be as convinced.

Edited by AndyJWest

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3 hours ago, ZachariasX said:

I‘d be careful going that far on the base of your original assumption about wing size, as it lacks critical issues.

 

The lower wing is less efficient than the top wing, as the top wing shields part if the lift mediated by the lower wing. The closer the wings are together (in relation to thei chord length) the more pronounced the effect. In this sense, you can see the lower wing mostly as a rigging aid to create a safe top wing arrangement.

 

The sesquiplane arrangement is just that. It makes the lower wing what it really is, a rigging aid, with least drag. At normal flight speeds, AoA is so small anyway that there that I would be very surprised if there was a difference in induced drag with such light aircraft. At least for practical purposes. Albatros did just that in newer models, reduce the lower wing to the rigging aid it essentially always was.

 

Albatross did indeed do that: just a few weeks ago I mentioned an interview in Aeroplane Magazine, Nov issue, with one of the pilots from the Vintage Aviator saying that "interestingly, our 180 hp D.II is slightly faster than the D.Vas, with the same power plant". And as we know they tended to shed lower wings, due to flutter and warping at speed. So I am not convinced that the theoretical advantages of the sesquiplane translated well into practice.  Of course there were other reasons why the D.Vs were crap aeroplanes, not the sleek boom and zoom predators of RoF forum imagination. ( Simply put, if you are flying defensively so that you can choose your fights, having two MGs per plane instead of one, you already have a much bigger advantage than would be provided by any marginal speed edge).   But I see no evidence that any actual benefits were gained from a sesquiplane configuration, except a better view downwards, (at your failing lower wing ;) ).   

 

There were plenty of post war biplane designs Gladiator, Fury etc but I do not recall many of them being sesqiplanes. Certainly it seems UK designers were unconvinced. 

But I do agree that if Sopwith had been able to put the Fokker D.VIII's wing on a Pup it would have been better. Fortunately for the Entente, A.F. did not come up with this until it was too late.

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Good lord. It's for fun.

 

We are here and do all this for fun, right guys?

 

Right?

 

Guys??????

 

Hellooo????

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1 hour ago, US213_Talbot said:

Good lord.

Yes?

 

1 hour ago, US213_Talbot said:

It's for fun.

What are you talking about; this is a flight sim forum. This serious. Remember, I once drowned them all for such misbehaving.

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2 minutes ago, US213_Talbot said:

I'll be sure not to fly near you....

You know, in a Hanriot HD2 you'd be safe.

Edited by ZachariasX

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1 hour ago, US213_Talbot said:

I'm allergic to chocolate. 

 

So what if the N28 comes your way will allergy help?

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12 minutes ago, West said:

So what if the N28 comes your way will allergy help?

Funny that you mention that one.

3 hours ago, unreasonable said:

saying that "interestingly, our 180 hp D.II is slightly faster than the D.Vas, with the same power plant". And as we know they tended to shed lower wings, due to flutter and warping at speed.

... that N28 one was the only biplane of the series worth mentioning apart from the sesquiplanes and all it was known for is shedding wings. Well, the draperies. (French, huh?) But for practical purposes the same result. But I do see your point.

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My static run up yesterday was between 1150-1200 rpm.  I can't get any better resolution because the RPM (French Jaeger) only really works in 50 rpm increments.  This may mean my prop is under pitched which would prevent me from achieving a really high speed on the Dr.I.  However, since we do know the pitch, static RPM etc, these are things that are measurable and could be reproduced in ROF if they wanted to do it.  

 

A friend on FB posted this yesterday:

(He is running new build 100 Gnome engines.  Incorporating modern technology (ignition, cylinder porting, etc) they are geting 120+ HP on the dyno) For reference, a new 80 Rhone would produce 90 Hp at top rpm.

 

"Reason for run today was to check a new prop. Its a German tri plane style and similar specs to the camel style one we normally run. On our test rig we were pulling 1200 rpm, so figured it was a little under prop ed. Its great to be able to test for real. Our normal camel style one, straight and level 1200 rpm and 110 mph. Tri plane got to 100 mph but had to blip engine as it got to 1300 rpm which is too high. Pilot said with the triplane prop fitted it was the fast accelerating aircraft he had ever flown, pulled 1200 rpm in the climb and was "like a rocket"!! New prop underway."

 

Here he is saying that they are using a Camel propeller on the 100 Gnome, and putting that on the Pup.  Think about that! The 100 Gnome is turning the Camel prop at rated RPM!  It would be the equivalent of putting the 130 Clerget on the Pup...so I am extremely doubtful at this point that the 80 Rhone Could take the Pup to 110 mph in level flight without burning up the motor, even then, I am skeptical.  Based upon drag-power relationships, I estimate the Pup's top speed with an 80 Rhone at 100 mph +/- 2 mph

 

In reference to the "triplane" he is talking about a Dr.I style axial prop.  The prop is under pitched, so he is hitting the RPM limit before he is hitting the max speed limit of the plane.  Indeed, the triplane prop is under pitched for the Pup/Gnome application. But it sure does climb well! hahahaha

Edited by Chill31
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51 minutes ago, AndyJWest said:

I wonder how accurate tachometers were during WWI? 

I checked my tach with a light sensing digital tach, and the WWI tach seems to be spot on when I check it at a known rpm (750 and 1100).

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6 minutes ago, Chill31 said:

I checked my tach with a light sensing digital tach, and the WWI tach seems to be spot on when I check it at a known rpm (750 and 1100).

I get the impression that our "new" rotaries have way stronger horses than the ones coming off the assembly shacks back then. Not just production quality, but also fuel and lubrication helps.

 

I mean, I see that with with vintage car engines. If you overhaul them such that you set them back to zero miles, you would sometime be asked, "How many horsepower you want?" In addition, what is available exceeds what it had back then by a good margin. I have yet to find one account of a Pup pilot saying that he had to throttle back because he would overrev in level flight. Regarding the Triplane, it makes sense that the prop is under pitched since it was Antony’s deliberate choice to do so.

 

Still, if you could measure flight speeds at 1000 rpm, 1100 rpm and 1200 rpm then we would get some good guesses regarding speed.

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The "pitch X rpm" method of determining speed works better with boats than planes because of differences in fluid mass density.  In the air, it's a ballpark guesstimation at best.

 

Chill, I'd go with the speediest prop you can get as long as it doesn't cost in climb.  Seems to me that, for a Dr.1, top end would be more useful than "quick off the chocks."  (It's already pretty quick; it just needs to be faster, no?)

 

Looking good, buddy.  Keep posting updates.   

Edited by Todt_Von_Oben

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17 hours ago, unreasonable said:

 

No misprint required, just examination of contemporary documents.   Bruce's British Aeroplanes 1914-18 gives two test reports for a Pup, with the sea level top speeds given at 111.5 mph (80 hp Le Rhone) and 110 mph (100hp Monosoupape)

 

111.5 mph = 179.4 kph.

 

111.5mph is such a specific number, to the point five mile no less. Royal Navy standards, that!

 

In fact, it's just the conversion of 97 knots, or roughly 179.5km/h.

 

My misprint theory still holds water when we consider that 87 knots is roughly 100mph or 161km/h, a figure which we find at The Aerodrome (along with another figure of 106mph, both without source).

 

 

But if you find that theory of a 9 changing into an 8 far-fetched and trust neither the Aerodrome nor the Royal Navy, and I'm in the same boat (pun intended), I propose an even better theory.

 

During the speed measurements at the RNAS, the value of 97 was noted. But not knots. Miles per hour. I mean, that's what you can read on the airspeed indicator, right? So simply put: a wrong unit was used. It wouldn't be the first nor the last time.

 

For the record: 97mph = 156km/h

 

Which makes sense, considering the top speed of the Nieuport 11 is also 156km/h. Now reality is often stranger than fiction, and the British were very good at reducing drag through making wings and bracing wires thinner, so I concede that the Pup was likely faster than the pre-war Nieuport 10/11 design. That still won't get you 180km/h out of an 80hp engine running at 1200rpm.

 

Occam's razor.

 

 

 

Besides,

 

ulfCy9A.jpg

 

Oh yes.

 

 

P.S. 110mph for the 100hp Monosoupape makes more sense.

Edited by J5_Hellbender-Sch27b
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Out of curiosity; do we know how these tests were made at the time?

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I think that I will have a chance to fly an 80 Rhone Pup once I get some time in the Dr.I.  but everyone I have talked to who flies one says it is quite slow.  I have only 2 data points: 110 mph level flight with a Camel prop spinning 1200 rpm and 110 mph in a dive with the 80 Rhone spinning 1200 rpm (that is the Vintage Aviators Pup, so it is probably very accurate).

 

I thought this video showcased the different sounds of the engine pretty well, so figured I'd share it with you guys. 500 rpm and 1000 rpm

 

 

Edited by Chill31
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7 hours ago, J5_Hellbender-Sch27b said:

 

111.5mph is such a specific number, to the point five mile no less. Royal Navy standards, that!

 

In fact, it's just the conversion of 97 knots, or roughly 179.5km/h.

 

My misprint theory still holds water when we consider that 87 knots is roughly 100mph or 161km/h, a figure which we find at The Aerodrome (along with another figure of 106mph, both without source).

 

 

But if you find that theory of a 9 changing into an 8 far-fetched and trust neither the Aerodrome nor the Royal Navy, and I'm in the same boat (pun intended), I propose an even better theory.

 

During the speed measurements at the RNAS, the value of 97 was noted. But not knots. Miles per hour. I mean, that's what you can read on the airspeed indicator, right? So simply put: a wrong unit was used. It wouldn't be the first nor the last time.

 

For the record: 97mph = 156km/h

 

Which makes sense, considering the top speed of the Nieuport 11 is also 156km/h. Now reality is often stranger than fiction, and the British were very good at reducing drag through making wings and bracing wires thinner, so I concede that the Pup was likely faster than the pre-war Nieuport 10/11 design. That still won't get you 180km/h out of an 80hp engine running at 1200rpm.

 

Occam's razor.

 

P.S. 110mph for the 100hp Monosoupape makes more sense.

 

Good post, I cannot rule out a simple human error, although it does seem awfully convenient.  Although you concede that the Pup might be faster, your argument still uses the premise that it should have exactly the same speed as the N.11    RNAS No.8 Squadron ditched their Nieuports for Pups as soon as they could: other reasons than speed would of course have played a part, but I have yet to see anyone claim that the N.11 was as good a fighting machine as a Pup. Why this assumption? As previously posted, the Vintage Aviator's Albatross DVa is noticeably slower than the D.II with the same engine: basing your whole argument on the assumption that the speeds were the same undermines it, IMHO.  Occam's razor would suggest the simplest explanation - which is that the test reports are at least roughly right and the N.11 is slower than a Pup.  If we had some consistent contemporary  modern test results I would be convinced.

 

Unsourced numbers on internet sites require no response. FYI The test report in Bruce gives the speeds at altitude: here for the Le Rhone, with the Knot conversion using the Admiralty Knot, of 6080ft used in the UK until 1970. I am not sure why the test report would show the extra decimal place only for the SL mph number. If you round the Kt figure to the nearest Kt, since one is supposing that this was actually mph read from the dial, then convert to mph to one decimal place using 6080ft, then round again, you find that the 103 value would be 104 mph.  ;)   

 

SL - 111.5 mph    96.8 kt     

5,000ft - 105 mph   91.2 kt

7 & 9,000ft - 103 mph  89.4 kt

11,000ft - 101 mph  87.7 kt

13,000 - 98 mph  85.1 kt

15,000 - 85 mph  73.8 kt

 

A lot depends on the propeller used as well.  For the tests this is stated as L.P. 1020 (Le Rhone) and Vickers 57 (Mono). This means nothing to me but someone may know if it makes a significant difference.  Bruce says many of the Home Defence Pups were fitted with Monosoupapes.  They needed rate of climb, so it is possible they were fitted with a finer airscrew, but that is conjecture.

 

 

 

 

6 hours ago, DD_Arthur said:

Out of curiosity; do we know how these tests were made at the time?

 

Bruce gives the bare numbers for performance (speed, time to climb, ceiling, endurance) plus weight details, engine and prop type. The trials are dated, (no place give) so if you had a weather report for that day you could attempt a heroic temperature adjustment, but as they were in the UK it is safe to assume that it was always chilly!  No idea if the original archives have more detail.

Edited by unreasonable
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10 hours ago, DD_Arthur said:

Out of curiosity; do we know how these tests were made at the time?

 

As far as I know, primary sources are pretty much lost across the board. I'd love to be wrong and see some of those documents, though.

 

 

5 hours ago, unreasonable said:

Good post, I cannot rule out a simple human error, although it does seem awfully convenient.  Although you concede that the Pup might be faster, your argument still uses the premise that it should have exactly the same speed as the N.11    RNAS No.8 Squadron ditched their Nieuports for Pups as soon as they could: other reasons than speed would of course have played a part, but I have yet to see anyone claim that the N.11 was as good a fighting machine as a Pup. Why this assumption? As previously posted, the Vintage Aviator's Albatross DVa is noticeably slower than the D.II with the same engine: basing your whole argument on the assumption that the speeds were the same undermines it, IMHO.  Occam's razor would suggest the simplest explanation - which is that the test reports are at least roughly right and the N.11 is slower than a Pup.  If we had some consistent contemporary  modern test results I would be convinced.

 

Unsourced numbers on internet sites require no response. FYI The test report in Bruce gives the speeds at altitude: here for the Le Rhone, with the Knot conversion using the Admiralty Knot, of 6080ft used in the UK until 1970. I am not sure why the test report would show the extra decimal place only for the SL mph number. If you round the Kt figure to the nearest Kt, since one is supposing that this was actually mph read from the dial, then convert to mph to one decimal place using 6080ft, then round again, you find that the 103 value would be 104 mph.  ;)   

 

SL - 111.5 mph    96.8 kt     

5,000ft - 105 mph   91.2 kt

7 & 9,000ft - 103 mph  89.4 kt

11,000ft - 101 mph  87.7 kt

13,000 - 98 mph  85.1 kt

15,000 - 85 mph  73.8 kt

 

A lot depends on the propeller used as well.  For the tests this is stated as L.P. 1020 (Le Rhone) and Vickers 57 (Mono). This means nothing to me but someone may know if it makes a significant difference.  Bruce says many of the Home Defence Pups were fitted with Monosoupapes.  They needed rate of climb, so it is possible they were fitted with a finer airscrew, but that is conjecture.

 

Also a good post and good points. (see we can discuss this without fighting!)

 

 

I have to admit that quite a lot of results make sense, ranging from 97mph (156km/h) all the way to 106mph (170km/h), seeing how we also have the Nieuport 11 reported anywhere between 156km/h and 165km/h. I'm very inclined to believe that the Pup was faster than the Nieuport 11, and both machines climbed essentially the same.

 

If @Chill31 says the Pup pilots he knows struggle to reach 90mph IAS, that still doesn't mean they're not reaching close to 100mph TAS. For these light planes flying at relatively low speeds, TAS at almost any altitude is relatively close to IAS at sea level.

 

This is especially clear in Gray & Thetford's German Aircraft of the First World War, where all of the 180hp Mercedes D.IIIa machines are listed as having a top speed of 165km/h, given at various altitudes:

 

  • Albatros D.III: 165km/h, no altitude specified. Climb to 1000m in 4min.
     
  • Albatros D.Va: 165km/h, no altitude specified. Climb to 1000m in 4min.
     
  • Pfalz D.IIIa: 165km/h at 3000m. Climb to 1000m in 3.25min.
     
  • Halberstadt CL.II: 165km/h at 5000m(!!). Climb to 1000m in 5min.

 

 

While the two 160hp Mercedes D.III engine powered scouts are actually faster in level speed, but don't climb nearly as well:

 

  • Albatros D.II: 175km/h, with no altitude given. Climb to 1000m in 5min.
     
  • Fokker D.VII: 186.5km/h at 1000m. Climb to 1000m in 3.8min

 

 

<tangent>

 

Yes, the original "early" Fokker D.VII which competed at Adlershof and which we currently have in-game had a 160hp Mercedes D.III, not a 180hp Mercedes D.IIIa.

 

However, to make it even more confusing: the D.III and D.IIIa were essentially the same engine block. The D.IIIa was simply a slightly uprated D.III produced as of June 1917, and would have been rapidly converted into the D.IIIaü by late 1917/mid 1918.

 

Comparing the German measurements expressed in metric horsepower (ps / Pferdestärke) to the post-war tests by the British expressed in mechanical horsepower (hp), we come to the following ratings:

Mercedes D.III: 160ps (no British post-war measurements, likely 170-175hp)

Mercedes D.IIIa: 170ps (180hp by British post-war measurements)

Mercedes D.IIIaü: 180ps (200hp by British post-war measurements)

 

For the record: these are not 1:1 conversions, as the figures in horsepower would actually be less than those in Pferdestärke (1ps = 0.99hp), but rather new measurements expressed directly in horsepower.

 

</tangent>

 

 

My conclusion is simple: engines and propellers were adapted for better climb rather than better level speed as the war progressed.

 

Likewise, comparing the Nieuport 11 to the Nieuport 17, we also notice that the N17 may have not been much faster (or even slower) than the N11 in level speed, but was a far better climber.

 

 

I believe that Chill's Fokker Dr.I will shed quite some light on the performance of both the Dr.I and the Pup with the 80hp Le Rhone. While the Dr.Is three wings (and a tiny extra wing in between the gear) may not have been the most efficient design, it was indeed the first internally braced "thick-wing" cantilever Fokker, with the outboard struts only necessary to counter vibration. I sincerely doubt that it will be slower than the externally braced Pup with the same engine. All we need to know is its top TAS in level flight.

 

Exciting times!

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What I read among first hand diares and reports plus official  letters of RFC Admirality, there is clear picture that all Entante scouts that they have use since end of  1916 were slower and can't climb so high to be competitive against new German scouts (albatros DI and DII). They were referring to Niuports 11 or Pups, Dh2 other obvious two-seaters fighters. I don't remember well enough , but post December 15 patch pup was faster than alb2 but after patch was slower, which is correct I think. If there ever will be FC2 it can be reversed again... 

Edited by 1PL-Husar-1Esk

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

What I read among first hand diares and reports plus official  letters of RFC Admirality, there is clear picture that all Entante scouts that they have use since end of  1916 were slower and can't climb so high to be competitive against new German scouts (albatros DI and DII). They were referring to Niuports 11 or Pups, Dh2 other obvious two-seaters fighters. I don't remember well enough , but post December 15 patch pup was faster than alb2 but after patch was slower, which is correct I think. If there ever will be FC2 it can be reversed again... 

 

Not all of 1.034 was reverted, the Fokker Dr.I, which this thread is about, remains the same.

 

The Bristol Fighter, too, which saw a reduction in rate of climb and roll, is also "after 1.034". It's nothing something I like to mention too often on the forum, for fear of being accused of two-seater bias. I think we can all agree that the Sopwith Triplane was hit the heaviest, and that the Nieuport 28 indeed needed its takeoff fix.

 

For anyone who needs a refresher of the changes: https://riseofflight.com/forum/topic/44725-version-1034/

 

 

Still, I recommend we keep the discussion on topic of Chill's Fokker Dr.I.

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Ok, I finally flew a Rhone powered triplane!!  

 

My level flight speed is about 93 knots, but I need to test it more to get solid data.  Of note, my static RPM was 1200 on the run up today and I hit the rev limit of 1300 rpm @ 107 mph (173kmh).  The plane would go faster if I had a hi-speed prop fitted.  As it is, it is very much a climb prop, and it climbs readily (though I don't have good data for climb rate yet).  Next few flights, I'll get some good data nailed down.  

 

Here is a short fly by video: 

 

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9 minutes ago, Chill31 said:

Ok, I finally flew a Rhone powered triplane!!  

 

Where's the 'green with envy'' emoji?

 

Sounds wonderful. Was that flat out? Seemed to be flying in a noticeable nose-down attitude.

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4 minutes ago, AndyJWest said:

 

Where's the 'green with envy'' emoji?

 

Sounds wonderful. Was that flat out? Seemed to be flying in a noticeable nose-down attitude.

Yeah, it was pretty close to flat out.  I made that pass at 1250 rpm, so it was probably right around 105 mph.

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9 hours ago, Chill31 said:

Ok, I finally flew a Rhone powered triplane!!  

 

My level flight speed is about 93 knots, but I need to test it more to get solid data.  Of note, my static RPM was 1200 on the run up today and I hit the rev limit of 1300 rpm @ 107 mph (173kmh).  The plane would go faster if I had a hi-speed prop fitted.  As it is, it is very much a climb prop, and it climbs readily (though I don't have good data for climb rate yet).  Next few flights, I'll get some good data nailed down.  

 

Impressive! Beautiful sound! Thank you so much for making the effort to install equipment on your plane to measure these things. How's the gyroscopic forces? Hard to land or turn left? The Le Rhône 110/20hp would have the gyroscopic forces a bit more pronounced, right?

Edited by SeaW0lf

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Man super bummed I missed it. Saturday was my only free day to make it. Family came in from out of town sunday.

 

Great videos, a camel there too!

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The first thing that springs to my mind is that your elevator seems to be just slightly deflected in level flight and not that prominent deflected downwards as in FC to counter the lift. Can you tell us more about the lift in your Dr.I is it that nasty that when you fly level with max RPM that you have to stop it from climbing all the time?

Edited by J99_Sizzlorr

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7 hours ago, SeaW0lf said:

 

Impressive! Beautiful sound! Thank you so much for making the effort to install equipment on your plane to measure these things. How's the gyroscopic forces? Hard to land or turn left? The Le Rhône 110/20hp would have the gyroscopic forces a bit more pronounced, right?

On this flight, I did not do any "combat" turns.  I will be able to pay better attention to the gyroscopic forces as I fly it more, however, it didn't do anything so unusual that I noticed it right away.  One thing I did find to be similar (I need to get on FC and compare directly) is that when I throttle back to land and push the blip switch, the plane rolls a little to the right when the engine torque is gone.  

 

The Rhone 9J is about 50 lbs heavier than the 9C, so it will have more gyroscopic effect.  

 

Once I start doing aerobatics with it, I think that is when I will start to notice these effects.  I'll have videos on my next flight as my GoPros died while I was waiting for the weather to improve.

 

 

6 hours ago, US213_Talbot said:

Man super bummed I missed it. Saturday was my only free day to make it. Family came in from out of town sunday.

 

Great videos, a camel there too!

Yeah, sorry about that.  The weather just wouldn't cooperate with me the way I wanted.  I'll post on facebook a day when I am planning to fly, so visitors can come see it.

 

6 hours ago, J99_Sizzlorr said:

The first thin that springs to my mind is that your elevator seems to be just slightly deflected in level flight and not that prominent deflected downwards as in FC to counter the lift. Can you tell us more about the lift in your Dr.I is it that nasty that when you fly level with max RPM that you have to stop it from climbing all the time?

With the Rhone 9C mounted, my plane is about 50 lbs too light on the nose, so it is definitely in a more tail heavy configuration right now.  I am attaching a couple of pictures.  In the close up picture, I am doing about 100 mph, and you can see there is very little nose down deflection of the elevator.  That said, I have to constantly push forward on the control stick for it to stay in that position.  Can't let go!  I will see if I can find a spring scale to measure how much force it takes.  

 

The Dr.I is so light and sensitive on the elevator control, the force isn't substantial, but it must be constantly applied.

80074557_605677133307045_9152482716871032832_n.thumb.jpg.eeed78344e48f7b2eec0c4003fa7a249.jpg79824174_768401730301987_6921374427825307648_n.thumb.jpg.284ee0b8032bb9886791d1fa820f7f39.jpg

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4 minutes ago, ZachariasX said:

What kind of prop are you using @Chill31?

It is a custom made propeller.  Since no Fokker Dr.Is were powered with 80 Rhones, there is no "historical" propeller to copy.  The builder of this prop copied the pitch and diameter from a propeller used on the Thomas Morse scout.  He then used the same would and lamination to make it look like an Axial propeller.  

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1 hour ago, Chill31 said:

With the Rhone 9C mounted, my plane is about 50 lbs too light on the nose, so it is definitely in a more tail heavy configuration right now.  I am attaching a couple of pictures.  In the close up picture, I am doing about 100 mph, and you can see there is very little nose down deflection of the elevator.  That said, I have to constantly push forward on the control stick for it to stay in that position.  Can't let go!  I will see if I can find a spring scale to measure how much force it takes.  

 

The Dr.I is so light and sensitive on the elevator control, the force isn't substantial, but it must be constantly applied.

 

Interesting....for reference a screen from FCs current Dr.I doing roughly 100 mph... notice the elevator deflection...

DRIelevator.thumb.jpg.fb32a72accdf15adbae801febb6ba3dc.jpg

 

Edited by J99_Sizzlorr
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37 minutes ago, J99_Sizzlorr said:

 

Interesting....for reference a screen from FCs current Dr.I doing roughly 100 mph... notice the elevator deflection...

DRIelevator.thumb.jpg.fb32a72accdf15adbae801febb6ba3dc.jpg

 

 

No significant Dr.1 elevator deflection can be seen also  in those original  movie footages from 1938 .

 

 

 

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1 hour ago, Chill31 said:

It is a custom made propeller.  Since no Fokker Dr.Is were powered with 80 Rhones, there is no "historical" propeller to copy.  The builder of this prop copied the pitch and diameter from a propeller used on the Thomas Morse scout.  He then used the same would and lamination to make it look like an Axial propeller.  

 

I predict you went 103 mph @ 1200 rpm. At 1250 rpm you go 107.4 mph. (Minus drag caused by the flutter of your cheeks, of course.)

 

You have 90.5 inches pitch on your prop if you were sold what you thought you‘d buy.

 

17 hours ago, Chill31 said:

Yeah, it was pretty close to flat out.  I made that pass at 1250 rpm, so it was probably right around 105 mph.

 

Oh boy. Who would have thought. Now we know the drag of your cheeks.

Edited by ZachariasX

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For anyone who wants to read about my first flight in the rotary Dr.I

 

 

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