Fokker Dr.I Discussion

[unreasonable]

1 hour ago, SeaW0lf said:

Hi, Chill, we have a doubt about the forward stick pressure in the Dr.1. Can you dive pushing the stick forward or this is not possible and you have to kind of cheat the elevator and sort of roll to dive it? As it seems, there is a player who can only fly straight with full forward pressure in the Il-2 Fokker Dr.1. In other words, he cannot dive the plane pushing the stick forward by any means. Is that correct?

 

This is rubbish - the FC Dr 1 can be pushed nose down at any speed, level flight at SL only requires about 1/3 forwards pressure. Please check it yourself before you repeat this nonsense.

[unreasonable]

13 minutes ago, Plank said:

This is absurd! Embrace!

 

 

Touché.  I must say, however, that if the stick pressure in the FC Dr 1 was absurd I might have to embrace it. As it is, it is only people posting on the forum who are being absurd, so I do not have to live up to my motto. (Except in your case, of course.   )    

[SeaW0lf]

3 hours ago, unreasonable said:

 

This is rubbish - the FC Dr 1 can be pushed nose down at any speed, level flight at SL only requires about 1/3 forwards pressure. Please check it yourself before you repeat this nonsense.

 

You were the one to question it. I though the idea was ludicrous so I'm asking Chill. I'm not so sure where you are going with this.

 

A player was saying he needed full stick forward to flight straight, and then I asked how he dived then (below) and unreasonable answered me:

 

-------

 

 

-------

 

I replyed that it made no sense at all and then I came here to ask you Chill. But since he seems to have come clear on it, don't bother. He must have been confused.

Edited August 25, 2018 by SeaW0lf

[CAFulcrum]

The key to keeping it level is not to fly with the throttle fully open.  It cruises at around 95kph iirc without any stick pressure.  At full speed you have to apply a lot of downward stick.  Without an adjustable horizontal stabilizer (like the SE5a has in ROF) it's stuck this way and totally normal.

 

The ffb in this are great btw!  Really enjoying both planes with my MS ffb2.

[Zooropa_Fly]

Apart from anything else, more elevator deflection = Slows you down !!

[HiIIBiIIy]

On 8/26/2018 at 11:52 AM, CAFulcrum said:

The key to keeping it level is not to fly with the throttle fully open.  It cruises at around 95kph iirc without any stick pressure.  At full speed you have to apply a lot of downward stick.  Without an adjustable horizontal stabilizer (like the SE5a has in ROF) it's stuck this way and totally normal.

 

 

"It cruises at 95 kph" are you serious? The real DR1 stalls at 72 kph, you should be cruising around 144 kph with little forward stick.

[unreasonable]

10 minutes ago, HiIIBiIIy said:

"It cruises at 95 kph" are you serious? The real DR1 stalls at 72 kph, you should be cruising around 144 kph with little forward stick.

 

He is saying "not to fly with the throttle fully open".  Cruising usually understood to mean below full throttle.  I got 95 kph at 800 rpm as well (edit close to SL). So yes he is not only serious he is absolutely correct at least at SL.  That is a very comfortable margin over stall speed.  To cruise at altitude you would need higher speeds: but 105 at 1000rpm and 3-4km is perfectly comfortable.

Edited August 28, 2018 by unreasonable

[HiIIBiIIy]

7 minutes ago, unreasonable said:

 

He is saying "not to fly with the throttle fully open".  Cruising usually understood to mean below full throttle.  I got 95 kph at 800 rpm as well. So yes he is not only serious he is absolutely correct.  That is a very comfortable margin over stall speed. 

95 kph is NOT cruise speed for the DR1, it should be a descending speed. 

[unreasonable]

12 minutes ago, HiIIBiIIy said:

95 kph is NOT cruise speed for the DR1, it should be a descending speed. 

 

The is no single cruise speed - if you mean hands off level flight, that is altitude dependent.  You can cruise at 95kph hands off level close to sea level - it was about 200m when I tried it.

 

Realistically for players in the "game zone" of altitudes up to 2km or so I would say that 900rpm and 105kph is a realistic cruise setting.    

 

[HiIIBiIIy]

9 hours ago, unreasonable said:

 

The is no single cruise speed - if you mean hands off level flight, that is altitude dependent.  You can cruise at 95kph hands off level close to sea level - it was about 200m when I tried it.

 

Realistically for players in the "game zone" of altitudes up to 2km or so I would say that 900rpm and 105kph is a realistic cruise setting.    

 

I think you have a great misconception of cruise speeds, yes cruise speed is less than full throttle but not in the lower envelope of flight.

Cruise speeds are usually about 80% throttle, example  Aeronca Chief has a top speed of 105 mph and a cruise speed of 95 mph.  

[HagarTheHorrible]

2 hours ago, HiIIBiIIy said:

I think you have a great misconception of cruise speeds, yes cruise speed is less than full throttle but not in the lower envelope of flight.

Cruise speeds are usually about 80% throttle, example  Aeronca Chief has a top speed of 105 mph and a cruise speed of 95 mph.  

 

 

Cruise speed is whatever is most applicable depending on circumstance.  If the limiting factor for pilots, flying aircraft without trim, was pilot fatigue then, all things being equal, that defines cruise speed, not relative performance figures. Obviously, pilots or flight commanders can modify those criteria, depending on tactical awareness, but it is always a compromise.  If the Dr1 flies at a certain speed, at a certain altitude, hands off, and pilot fatigue is the most pressing concern, to the player, then that is what it is. If that makes the Dr1 slow then that is for the pilot to decide what his priorities are. I do understand that players with FFB sticks might be at an advantage here but flying in a virtual space has never been equal.

 

No doubt, just to piss me off and teach me not to be so objectionable, my G940 will now go tits up and I'll have to find a non FFB alternative.

[HagarTheHorrible]

Bit extra info for those interested.

 

http://rwebs.net/avhistory/flight.htm

[Cynic_Al]

1 hour ago, HagarTheHorrible said:

Bit extra info for those interested.

 

http://rwebs.net/avhistory/flight.htm

 

No rotary, no comment.

[HagarTheHorrible]

1 hour ago, Cynic_Al said:

 

No rotary, no comment.

 

That's Chill31 out of the picture then !!!!

Edited August 28, 2018 by HagarTheHorrible

[HagarTheHorrible]

Very simply, he means that you don't need to follow the laid down runway, even landing diagonally to the usual line, if needed. The IMPORTANT thing is to land into the wind.

 

Might upset people with epilates though, so I suggest finding a hanger as far as possible from the control tower.

Edited August 28, 2018 by HagarTheHorrible

[HagarTheHorrible]

The Obedient Wives Club (OWC),  try that for starters.

 

Ok, scrub that last one try this one instead ; 

The Order Of Chaeronea

Edited August 28, 2018 by HagarTheHorrible

[Chill31]

On 8/25/2018 at 2:17 AM, SeaW0lf said:

Hi, Chill, we have a doubt about the forward stick pressure in the Dr.1. Can you dive pushing the stick forward or this is not possible and you have to kind of cheat the elevator and sort of roll to dive it? As it seems, there is a player who can only fly straight with full forward pressure in the Il-2 Fokker Dr.1. In other words, he cannot dive the plane pushing the stick forward by any means. Is that correct?

 

It seems this may already be addressed, but...the real Dr1, flying with as much down elevator as is depicted graphically in FC/ROF, would be pretty much unable to pitch nose down due to the stick hitting the ammo can.  That being said, in my version of FC, I have plenty of elevator authority to pitch down.

 

On 8/26/2018 at 12:52 PM, CAFulcrum said:

The key to keeping it level is not to fly with the throttle fully open.  It cruises at around 95kph iirc without any stick pressure.  At full speed you have to apply a lot of downward stick.  Without an adjustable horizontal stabilizer (like the SE5a has in ROF) it's stuck this way and totally normal.

 

The ffb in this are great btw!  Really enjoying both planes with my MS ffb2.

 

95 kph is about 60 mph.  60 mph in a Dr1 is...way to slow for patrolling the sky.  If you were to get surprised at that speed, you would have very little energy to use for maneuvering.  On page 2 of this thread, I posted a video of my Werner Voss tribute, and the second turn I made in that video was at about 65 mph, and it was not eager to turn very tight.

 

I flew the Dr1 on a cross-country flight (5.5 hrs that day), and it cruises along nicely at about 85 mph with a little forward stick pressure (didnt have a way to measure it at the time, but I will in the future).  After a couple of hours, my hand cramped up though...

 

2 hours ago, Cynic_Al said:

 

No rotary, no comment.

 

I always find this comment interesting.  It is as if you are suggesting there is a big difference between a Dr1 with a rotary and one without.  Tell me this, if you shut off the engine of a Lycoming powered Dr1 and the engine of a rotary powered Dr1, how should they fly?  You already know of course, they should be the same!  The majority of the aerodynamics of the plane come from the shape of it.  Some comes from the propwash of the bigger propeller found on rotary powered Dr1s.  And there is some physics involved in the gyroscopic precession.  

 

One of my friends has flown a Dr1 with a lycoming, a 120 Rhone, and an 80 Rhone.  According to him, there isn't as much difference as you might expect.  I guess I shall see for myself soon!  You fine folks will be the first to know of course

[Cynic_Al]

3 hours ago, Plank said:

oh I see.

 

So they mean land INTO THE WIND not along the painted stripes on the tarmac.

Even if that means landing DIAGONALLY across the stripes, lanes, access paths, pediways, rose beds, carparks etc

 

 

 

No, they mean you do follow the marked runway (if there is one), because in the presence of a crosswind you can approach diagonally, only straightening-up just before touchdown.

 

Examples of diverse quality.

 

=================================

 

2 hours ago, Chill31 said:

I always find this comment interesting.  It is as if you are suggesting there is a big difference between a Dr1 with a rotary and one without.  Tell me this, if you shut off the engine of a Lycoming powered Dr1 and the engine of a rotary powered Dr1, how should they fly?  You already know of course, they should be the same!

 

No argument there, but you won't get very far with the engine off so I don't see how it relates to reality.

 

Quote

 

 And there is some physics involved in the gyroscopic precession.  
 

 

 

Which I would counsel anyone not to underestimate, regardless of anecdotal evidence.

 

Quote

One of my friends has flown a Dr1 with a lycoming, a 120 Rhone, and an 80 Rhone.  According to him, there isn't as much difference as you might expect.  I guess I shall see for myself soon!  You fine folks will be the first to know of course

 

Assuming that project comes to fruition, provided that the C of G is preserved,  I predict a decrease in pitch-up tendency.

Edited August 29, 2018 by Cynic_Al

[US103_Baer]

4 hours ago, HagarTheHorrible said:

The Obedient Wives Club (OWC),  try that for starters.

Haha, I remember that well Hagar. Perhaps we need an Obedient Pilots Club

OWC branch up in the far north there?

Edited August 29, 2018 by US103_Baer

[HagarTheHorrible]

7 hours ago, Cynic_Al said:

 

No, they mean you do follow the marked runway (if there is one), because in the presence of a crosswind you can approach diagonally, only straightening-up just before touchdown.

 

 

Might I suggest you read it again  .

 

He absolutely says "land into the wind", regardless of runway direction, only land against the wind as an absolute last resort, having previously ignored the advice to leave the aircraft parked in the hanger.  From all I have read, and observed, there is a point, regardless of how brilliant a pilot someone is where they become nothing more than a passenger and woe betide any Dr1 pilot who forgets that fact.  Flicking the tail around at the last moment, in a Dr1 is not an option, you might get away with it once, even twice, but eventually it's going to be embarrassing and expensive.

[Feathered_IV]

How loud is the Dr1 engine in reality?  In the game I can hear them quite clearly over the roar of a Rolls Royce Merlin at 85% throttle.

[ZachariasX]

10 hours ago, Cynic_Al said:

No, they mean you do follow the marked runway (if there is one), because in the presence of a crosswind you can approach diagonally, only straightening-up just before touchdown.

Out of these 10 landings, only one was done such that it wouldn't result in considerable damage to most taildraggers. No.1 was doing a fine job. He must. With that kite, going down crabwise would most certainly have him do somersaulting. But everyone else with their modern "safe" crates, they just put them down as it comes. And get away with it.

 

But  with such taildragers as the Dr:I, you land into the wind. Literally. If not, you MUST be proficient to flair out with an aileron bank such that the nose aligns with the runway. It irequires you to cross controls. It requires some practise. The high center of gravity also makes a significant aileron tilt undesirable. Much easier is going *directly" into the wind. There is a good reason why aerodromes of that era were somewhat square shaped or roundish patches of grass. You had your ground crew towing your aircraft from where you could take off straight into the wind.

 

Operiating these vintage crates not the way they were intended to makes them "hard to fly". The worst you can do is taking off and landing on concrete runways with crosswind. That is like taking off with an F-15 from a field.

[Chill31]

12 hours ago, Cynic_Al said:

Assuming that project comes to fruition, provided that the C of G is preserved,  I predict a decrease in pitch-up tendency.

 

I couldn't remember the original Dr.I W&B numbers, so I went and looked at them again to see how far off I was with my own Dr.I.  I was surprised to find that I am almost exactly in line with the original.

 

The numbers for the original are: 1406.5 lbs loaded weight with CG at 25.44

 

The numbers for my fully fueled loaded replica with a Lycoming engine: 1384 lbs with CG at 25.97

 

To be fair, the plans used to build my Dr.I used a late war fuel tank as would have been found on the Fokker D8.  To my knowledge, this tank was never used in the Dr.I.  The new tank I install will bring the CG forward some amount (don't know how much yet).  However, as it sits in the hangar right now, it is very close to the original numbers.  

 

For anyone who wants to play with Dr.I W&B:

 

5 hours ago, HagarTheHorrible said:

 

Might I suggest you read it again  .

 

He absolutely says "land into the wind", regardless of runway direction, only land against the wind as an absolute last resort, having previously ignored the advice to leave the aircraft parked in the hanger.  From all I have read, and observed, there is a point, regardless of how brilliant a pilot someone is where they become nothing more than a passenger and woe betide any Dr1 pilot who forgets that fact.  Flicking the tail around at the last moment, in a Dr1 is not an option, you might get away with it once, even twice, but eventually it's going to be embarrassing and expensive.

 

Ground handling is VERY different in this plane compared to modern planes, because it has no brakes.  Landing with one wing low ie. on one wheel, is very risk.  The tires are very narrow and do not handle side loads very well and are a lot more likely to roll off the rim.  I'm not sure exactly what would happen in that case, but it would be bad   

 

In one case, I went to go fly the Dr.I with a ~10 mph wind blowing.  It was diagonal across the runway, 30-40 degrees off runway heading.  I began taxiing to the end with a left, quartering tailwind.  Since there are no brakes, I can steer only from the propeller wind blowing over the rudder.  The wind from the rear caused the air over the rudder to be insufficient for steering, and the plane veered off the runway, disobeying me even after I added throttle to give it more airflow.  I had to shut down the motor to avoid rolling into the spectators watching from the side of the runway.

 

4 hours ago, Feathered_IV said:

How loud is the Dr1 engine in reality?  In the game I can hear them quite clearly over the roar of a Rolls Royce Merlin at 85% throttle.

 

Rotary engines are exceptionally loud because they do not have exhaust stacks.  Instead, there is simply a hole in the top of the cylinder for the exhaust.  In my Werner Voss tribute video, I fly close formation with a Piper Cub, which has a relatively quiet engine.  The Lycoming engine on My Dr.I has very short exhaust stacks, and people often comment on how loud it is.  What you hear in the video is what the people in the Cub hear.  I even asked if they could hear me after the flight, and they said no.  I will be surprised if their answer changes when I finish installing the rotary.

 

That being said, when I fly formation with the T-6 Texan, it is possible to hear the propeller when the wingman changes power settings aggressively, and when a jet powers up beside you in formation, it is audible as well.  This only happens in close formation though.

Edited August 29, 2018 by Chill31

[Chill31]

On 7/22/2018 at 8:56 AM, Chill31 said:

 

This is true to a limited degree.  You can shim the leading edge of the horizontal stabilizer to change the angle of incidence. However, from the manufactured position, you can only change it to give more nose down "trim".  I don't know if it was done in WWI though, and it would be impossible to get it removed completely since the bolt holes (that attach the horizontal stabilizer) would not line up at that point.

 

EDITED (I had not flown FC , only ROF a while ago, with MS FFB2 at the time I originally posted): I fly ROF/FC with a MS FFB2 and a TM Warthog with stick extension.  With MS FFB2, the FC Dr.I is perfect.  With the Warthog and stick extension, it seems about right as well.  If the elevator position depicted graphically is accurate to what is being simulated, then I think there is something off, and they should consider to rebalance the plane.

 

I just edited this post.  If you have a MS FFB2, you are experiencing a very realistic Dr. I control feel.

[CAFulcrum]

After flying again it actually flies hands off, neutral elevator at around 85 kph, just above stall speed, not really a cruising speed, but the stick pressure required up to about 100-110 isn't too strenuous.  Maybe it was just considered the optimal 'rake'/angle of the stab for turn fighting.  It must be angled for a specific reason -- setting it just above stall speed makes sense for a turnfighter.  What is the neutral/handsoff speed of the SPAD13 in comparison?

 

What I really like is that you can do spontaneous loops in the dr1 without the gyro effects completely taking over at the end.  Try it in RoF and you have to really fight to keep from spinning, here it falls right back into place.  I've specifically heard of this behavior so I was pretty wowed.

 

I am using an ffb2 and the feeling of the planes is incredible, especially the compression effects of high speed.  Big step up from RoF.  Much smoother too, a lot better feel of the air buffeting over the surfaces.

[Red_Von_Hammer]

3:11 is the part I like the best, and honestly is what I miss the most with the FM in FC, and (irrelevantly, but worth pointing out) RoF since the dreaded Dec-2014 patch in RoF as well.
Years ago saw a video of another guy (red baron paint scheme w/white cowling) do the same, but with a bit more angle, then returned to original course as if nothing ever happened.

[Todt_Von_Oben]

Thank you, Chris.  Your review answers every question I had about how the FC1 Dr.1 relates to a real-world counterpart.   I thought they might compare favorably but there's nothing like having that affirmed by someone who has actually flown both.  Thanks for sharing.  It helps.   (y)

[Chill31]

I am reviving this thread, since it was my intent for it to be all things Dr.I related for the FC forum...

 

Arising from the DM thread, I did some testing of the Fokker Dr.I, now powered by a 1917 80 hp Le Rhone, incorporating a G-meter and a modern GPS unit to give a speed reference (note: GPS speed is not airspeed and serves only as a general reference in this case).

 

I had several questions going into this flight.

1.) How many Gs am I pulling through loops, fast turns, and sustained turns?

2.) Can I make it flip out like the FC Dr.I during any accelerated stall generated by turning?

3) Can I make it flip out by simply being nose high and stalling?

 

Before I found the answer to #1, I thought I was pulling 2-2.5 Gs  during a loop.  The stick forces per G are VERY light in the Dr.I, the lightest of any aircraft I've flown.  Based on the seat of my pants and the stick forces, I thought the G forces were very low and questioned how it would be possible to pull 5 Gs like we do in FC.  What I found was that I hit 4-4.5 Gs during the initial pull on a loop, about .3 Gs inverted, and about 3 Gs coming down the back side of the loop.  I was shocked to find this out.  Sure, the math says it must be this way, BUT it feels so easy and effortless, I almost fell out of the plane from surprise.  I also did some defensive turns to the left and right.  Again, I was amazed that I was hitting 3+ Gs in the turn while trying to stay level.  

 

To answer #2, I did right and left turns while trying to stay level and hit a stall.  To the right, the airplane gently rolls to the inside of the turn.  I can stop it easily by unloading a little back stick force and then continuing the turn.  To the left, it was gentle as well.  However, the gyroscopic effects of the engine seemed to keep it from rolling into the turn.  Instead, I seemed to fall sideways.  I need to do a little more testing on the accelerated stalls to the left, since I cut my flight short as the sun went down.  In each case, it was a DEFINITE departure from the FC Dr.I behavior.  In FC, the Dr.I spins readily, and does wild gyrations when you try to turn left or stall while turning left.  This behavior is not supported by any of the flight testing I have done so far, and I would urge a FM review in this area.  

 

For #3, I pulled the nose up into a climbing left hand turn and continue the turn until I stalled.  All of these maneuvers were done with power on, 75% or more.  

 

Here is the video of the highlights, note at about 1 minute in, the engine quits from maneuvering, something I have never experienced in ROF/FC.

 

Edited June 1, 2020 by Chill31

[Tycoon]

1 hour ago, Chill31 said:

I am reviving this thread, since it was my intent for it to be all things Dr.I related for the FC forum...

 

Arising from the DM thread, I did some testing of the Fokker Dr.I, now powered by a 1917 80 hp Le Rhone, incorporating a G-meter and a modern GPS unit to give a speed reference (note: GPS speed is not airspeed and serves only as a general reference in this case).

 

I had several questions going into this flight.

1.) How many Gs am I pulling through loops, fast turns, and sustained turns?

2.) Can I make it flip out like the FC Dr.I during any accelerated stall generated by turning?

3) Can I make it flip out by simply being nose high and stalling?

 

Before I found the answer to #1, I thought I was pulling 2-2.5 Gs  during a loop.  The stick forces per G are VERY light in the Dr.I, the lightest of any aircraft I've flown.  Based on the seat of my pants and the stick forces, I thought the G forces were very low and questioned how it would be possible to pull 5 Gs like we do in FC.  What I found was that I hit 4-4.5 Gs during the initial pull on a loop, about .3 Gs inverted, and about 3 Gs coming down the back side of the loop.  I was shocked to find this out.  Sure, the math says it must be this way, BUT it feels so easy and effortless, I almost fell out of the plane from surprise.  I also did some defensive turns to the left and right.  Again, I was amazed that I was hitting 3+ Gs in the turn while trying to stay level.  

 

To answer #2, I did right and left turns while trying to stay level and hit a stall.  To the right, the airplane gently rolls to the inside of the turn.  I can stop it easily by unloading a little back stick force and then continuing the turn.  To the left, it was gentle as well.  However, the gyroscopic effects of the engine seemed to keep it from rolling into the turn.  Instead, I seemed to fall sideways.  I need to do a little more testing on the accelerated stalls to the left, since I cut my flight short as the sun went down.  In each case, it was a DEFINITE departure from the FC Dr.I behavior.  In FC, the Dr.I spins readily, and does wild gyrations when you try to turn left or stall while turning left.  This behavior is not supported by any of the flight testing I have done so far, and I would urge a FM review in this area.  

 

For #3, I pulled the nose up into a climbing left hand turn and continue the turn until I stalled.  All of these maneuvers were done with power on, 75% or more.  

 

Here is the video of the highlights, note at about 1 minute in, the engine quits from maneuvering, something I have never experienced in ROF/FC.

 

Now that you've flown with G meter how many max Gs do you feel your plane could handle?

[Chill31]

59 minutes ago, Tycoon said:

Now that you've flown with G meter how many max Gs do you feel your plane could handle?

Before breaking?  I think with more speed, I could definitely tap 7Gs. Considering the load testing I read about previously and how it handles 4 Gs, 7 is likely a reasonable maximum.  This is a complete guess however 

[Holtzauge]

Thanks for posting @Chill31. Interesting to see the view from the cockpit. Looks very much like I would expect: In a WW1 scout you trade either speed or altitude to keep up higher g-forces. Regarding the Dr1 C++ simulation results, I already posted those here.

 

As complementary information to this input on the Dr1, Javier Arango held an excellent lecture where he shared data from his Sopwith Camel that was equipped with what seems to be very sophisticated measuring equipment and he measured sustained turn times of 16 s in both left and right hand turns for the Camel.

Edited June 2, 2020 by Holtzauge

[Chill31]

Here are some initial C++ simulation results for a Dr1 at 757 Kg, 79 hp assumed at an altitude of 3000 ft STD at 15 deg C (I don’t know how much the Le Rhone loses with altitude from 85 hp at SL but I’ve assumed 79 hp at 3000 ft STD):

 

 

Max momentaneous turn at Clmax starting off at 85 mph IAS keeping altitude but letting speed drop: 13.5 s to do a 360 deg turn. Rough estimates based on the max initial turn rate at 85 mph IAS when entering turn for a 360 degree turn keeping speed up by dropping in altitude: circa 7.2 s.

 

Stationary turn time at 55 mph IAS keeping altitude: 18.5 s to do a 360 degree turn.

 

In the video I posted, you can time the turns to see how long they take.  I started out very aggressive and backed off until I made level turns and held altitude And did not stall.  I think I timed it at 10 seconds.

 

BTW: I found the text below on the Aerodrome forum by someone with the handle baldeagle which includes rolling in and out of the turn in a “Triplane” (I’m assuming a Dr1?) indicating I’m currently a bit pessimistic in my 18.5 estimate which does not include that:

 

“By the way, be careful where you get your numbers from, the last Triplane I flew I timed a 360 degree turn, from level to level again, so including rolling in and rolling out, and it was almost 20 seconds, even with Voss and a rotary engine it isn't going to be much less, certainly not anywhere near 5 seconds. Those figures you get from 1917 are measured by very uncertain means, not to mention the exaggerations made by manufacturers, pilots, and anybody with a point to make. I wouldn't put too much stock in contemporary figures, except in very general terms.”

 

Any thoughts on baldeagle’s comment above?

My power off stall is around 45 mph. Power on, it is much lower, maybe 30 mph?  I will have to do some detailed tests.  18.5 seconds seems like a long time, so does 20 with roll in and out.  Look at my video to see how long it takes to roll in and out.  I have not timed that yet. I’m not sure what the 5 second referencing, but it would be about right for 180 degrees of turn.  You may have just a little too much drag built in to your model?

 

[Holtzauge]

12 minutes ago, Chill31 said:

In the video I posted, you can time the turns to see how long they take.  I started out very aggressive and backed off until I made level turns and held altitude And did not stall.  I think I timed it at 10 seconds.

 

My power off stall is around 45 mph. Power on, it is much lower, maybe 30 mph?  I will have to do some detailed tests.  18.5 seconds seems like a long time, so does 20 with roll in and out.  Look at my video to see how long it takes to roll in and out.  I have not timed that yet. I’m not sure what the 5 second referencing, but it would be about right for 180 degrees of turn.  You may have just a little too much drag built in to your model?

 

 

Where in the video did you do a 360 degree stationary turn rate turn that took 10 s? What was the IAS you held doing that? I must have missed that. Could you specify where in the video those 10 s are?

 

I wrote 18.5 s as in 18 and a half not 5 s as such. The 20 s came as I said from someone with the handle "baldeagle" in The Aerodrome forum who it seems has flown a Triplane. Any idea who that is? I would have thought the Triplane flying community was rather small?

[unreasonable]

38 minutes ago, Chill31 said:

 

 

In the video I posted, you can time the turns to see how long they take.  I started out very aggressive and backed off until I made level turns and held altitude And did not stall.  I think I timed it at 10 seconds.

 

My power off stall is around 45 mph. Power on, it is much lower, maybe 30 mph?  I will have to do some detailed tests.  18.5 seconds seems like a long time, so does 20 with roll in and out.  Look at my video to see how long it takes to roll in and out.  I have not timed that yet. I’m not sure what the 5 second referencing, but it would be about right for 180 degrees of turn.  You may have just a little too much drag built in to your model?

 

 

Just attempted a rough comparison in the game at 1,000m at full rpm and I get something close to your results ~10 sec for 360 degrees, keeping as level as possible at about the same bank angle - just counting the time, so not desperately scientific.   It would be interesting if you compared.

 

 

 

 

 

5 minutes ago, Holtzauge said:

 

Where in the video did you do a 360 degree stationary turn rate turn that took 10 s? What was the IAS you held doing that? I must have missed that. Could you specify where in the video those 10 s are?

 

Watch 1.20 to 1.35 first 360, then does it again.

Edited June 2, 2020 by unreasonable

[Holtzauge]

@unreasonable Sure, in-game 9 s stationary turns are quite possible to do in a Dr1. Haven't clocked the Camel yet but I'm sure it would do that as well. In fact if both models have correct relative turn performance then it should do even better right?

 

Also: Are you quite sure the 1.20 to 1.35 s sequence is a stationary turn rate turn? Can't see either the speed or altitude and it looks like the g is not constant?

 

@Chill31: In the video sequence you posted, did you do a stationary turn rate 360 degree turn? If so where in the video sequence was that? What was the altitude and IAS speed maintained during the turn?

Edited June 2, 2020 by Holtzauge

[unreasonable]

6 hours ago, Holtzauge said:

@unreasonable Sure, in-game 9 s stationary turns are quite possible to do in a Dr1. Haven't clocked the Camel yet but I'm sure it would do that as well. In fact if both models have correct relative turn performance then it should do even better right?

 

Also: Are you quite sure the 1.20 to 1.35 s sequence is a stationary turn rate turn? Can't see either the speed or altitude and it looks like the g is not constant?maintained during the turn?

 

Of course I am not sure - as you say we cannot see his speed or altitude.  But I think the two turns starting at 1.20 are the ones to which Chill was referring.

 

I imagine getting the G, altitude and speed all exactly constant throughout the turn is as difficult in Chills Dr.1 as it is in the game.  I can just about do it in the  FC Fokker D.VII, but in the Dr.1  the sensitivity of the controls and general instability makes constant adjustments a must. We may be asking to much if we are expecting test pilot precision.

 

It is a pity that the FC planes do not come with the "Maximum performance turn" measured by Russian Bots shown in the Tech Specs page for all of the WW2 planes.  At least then you would have something consistent in-game measures to work with for your simulation comparisons.

[Chill31]

9 hours ago, Holtzauge said:

 

Where in the video did you do a 360 degree stationary turn rate turn that took 10 s? What was the IAS you held doing that? I must have missed that. Could you specify where in the video those 10 s are?

1:20.  Here it is wings level to wings level in about 12 seconds, maybe a shade over.  

1:35 It is wings level to passing through the reference point (the sun) in a bank in 10 seconds.

1:50 My turn stagnates because I stalled and had to relax back pressure. Took 14 seconds

2:03 This was my best and most stable turn. 10 seconds with no roll in/out.  Roll in/out ads about 1.5 seconds per roll.

--All of these turns were done at approximately 55 mph, with the first ones starting at a higher speed and bleeding down to 55, and 3,000 ft MSL.  It was about 80*F outside though, not 59*

 

I wrote 18.5 s as in 18 and a half not 5 s as such. The 20 s came as I said from someone with the handle "baldeagle" in The Aerodrome forum who it seems has flown a Triplane. Any idea who that is? I would have thought the Triplane flying community was rather small?

I do know who it is, and I think his info is already out there so I don't mind saying...it is Andrew King, former Old Rhinebeck Pilot.  He has never flown a Dr.I as accurate as mine.  ORAs Dr.Is are all...fat girls. They aren't going to turn or do anything nearly as well as mine.  Maybe that is why it took 20 seconds level to level instead of 12 or 13.

 

“By the way, be careful where you get your numbers from, the last Triplane I flew I timed a 360 degree turn, from level to level again, so including rolling in and rolling out, and it was almost 20 seconds, even with Voss and a rotary engine it isn't going to be much less, certainly not anywhere near 5 seconds. Those figures you get from 1917 are measured by very uncertain means, not to mention the exaggerations made by manufacturers, pilots, and anybody with a point to make. I wouldn't put too much stock in contemporary figures, except in very general terms.”

 

Any thoughts on baldeagle’s comment above?

 

Edited June 2, 2020 by Chill31

[Holtzauge]

13 hours ago, unreasonable said:

 

Of course I am not sure - as you say we cannot see his speed or altitude.  But I think the two turns starting at 1.20 are the ones to which Chill was referring.

 

I imagine getting the G, altitude and speed all exactly constant throughout the turn is as difficult in Chills Dr.1 as it is in the game.  I can just about do it in the  FC Fokker D.VII, but in the Dr.1  the sensitivity of the controls and general instability makes constant adjustments a must. We may be asking to much if we are expecting test pilot precision.

 

It is a pity that the FC planes do not come with the "Maximum performance turn" measured by Russian Bots shown in the Tech Specs page for all of the WW2 planes.  At least then you would have something consistent in-game measures to work with for your simulation comparisons.

 

Well in-game I did what I consider quite stable sustained 9 s turns to the left in the Dr1. The reason I did left turns is I fly much better going that way which is the same IRL actually (Gliders and light planes of course) so I should practice my right hand turns more. Anyway, at 1 Km altitude my C++ simulation indicates a sustained turn rate of 12.4 s for the Dr1 with a 122 hp Oberursel, i.e. that it would take 38% longer to do a similar turn. This is why I'm pursuing this to try to find out if I'm being pessimistic or FC optimistic.

 

Edit: The in-game test may have been at 750 m in which case the C++ gives about 12 s.

 

12 hours ago, Chill31 said:

1:20.  Here it is wings level to wings level in about 12 seconds, maybe a shade over.  

1:35 It is wings level to passing through the reference point (the sun) in a bank in 10 seconds.

1:50 My turn stagnates because I stalled and had to relax back pressure. Took 14 seconds

2:03 This was my best and most stable turn. 10 seconds with no roll in/out.  Roll in/out ads about 1.5 seconds per roll.

--All of these turns were done at approximately 55 mph, with the first ones starting at a higher speed and bleeding down to 55, and 3,000 ft MSL.  It was about 80*F outside though, not 59*

 

I do know who it is, and I think his info is already out there so I don't mind saying...it is Andrew King, former Old Rhinebeck Pilot.  He has never flown a Dr.I as accurate as mine.  ORAs Dr.Is are all...fat girls. They aren't going to turn or do anything nearly as well as mine.  Maybe that is why it took 20 seconds level to level instead of 12 or 13.

 

When I studied the video in more detail my attention was drawn to the instrument on the left. As far as I can tell this is a Garmin 296 or similar and the reading in the upper left hand corner should then be Knots Ground Speed. Unfortunately your IAS speed in Mph only shows a few times in the video and since the GPS based GS readout varies a lot its difficult to calibrate but it looks like 57-63 Knots GPS GS corresponds to a little over 80 mph IAS on your speedometer.

 

Regarding what is closest to a stationary turn in the video I did the exact same observation as you: The most steady turning with nose attitude held and stable g’s is around 2:02 to 2:12. But using the Garmin as a reference, it looks like you are dropping in speed from ca 63 Knots GS in the entry to 44-55 Knots IAS during the course of the turn. We could of course argue about the minutes of the readout and how accurate it is to do this connection between the Garmin GS and your IAS but I think it is pretty clear that you are losing speed in the 2:02 to 2:12 sequence meaning this is no sustained turn. The turns before that are more momentaneous in character IMHO (e.g. the 1:20 to 1:35 sequence) since the g is not held constant.

 

About the old Rhinebeck Dr1’s being so different to yours I don’t see by the specifications what could explain that your Dr1 can do a 10 s sustained turn whereas the Old Rhinebeck Dr1’s would require circa 18 s? The stated weight for the Old Rhinebeck replicas is 1290 lb (586 Kg) and they are powered by a Le Rhone. Why on earth would your machines produce such different results? Why deride them as “fat girls”?

 

I see now which 5 s you were referencing to and from theoretical calculations using simply Clmax, weight and wing area a 70-80 deg/s turn rate is quite achievable. However it is erroneous to take 360/72 to arrive at 5 s because while that may be achieved theoretically (though I doubt in practice) in a spiral dive but never in what IMO could be termed a turn. However, if you looked at the Javier Arango lecture I posted earlier on they may well back in the day have called that a "turn" as he explains about the different terminology used now and then.

Edited June 3, 2020 by Holtzauge

[Chill31]

1 hour ago, Holtzauge said:

When I studied the video in more detail my attention was drawn to the instrument on the left. As far as I can tell this is a Garmin 296 or similar and the reading in the upper left hand corner should then be Knots Ground Speed. Unfortunately your IAS speed in Mph only shows a few times in the video and since the GPS based GS readout varies a lot its difficult to calibrate but it looks like 57-63 Knots GPS GS corresponds to a little over 80 mph IAS on your speedometer.

My airspeed indicator is always off by 10-20 mph, depending on my speed.  The faster I go, the more it is off, since my static port on the instrument dumps directly into the cockpit where the pressure decreases as speed increases.  At a given airspeed, it is consistently inaccurate though, so you have come up with the same estimate I made.

 

Regarding what is closest to a stationary turn in the video I did the exact same observation as you: The most steady turning with nose attitude held and stable g’s is around 2:02 to 2:12. But using the Garmin as a reference, it looks like you are dropping in speed from ca 63 Knots GS in the entry to 44-55 Knots IAS during the course of the turn. We could of course argue about the minutes of the readout and how accurate it is to do this connection between the Garmin GS and your IAS but I think it is pretty clear that you are losing speed in the 2:02 to 2:12 sequence meaning this is no sustained turn. The turns before that are more momentaneous in character IMHO (e.g. the 1:20 to 1:35 sequence) since the g is not held constant.

Watch the nose position and G loading. It is pretty consistent, but you are right, I could do better.  The speed on the GPS is not perfectly accurate either, and it has a slight lag.  Look for the lake off the nose about 2:05.  That is approximately 90 degrees off my initial heading, and the speed is already down to 45-50kts.  The rest of the turn takes 8 seconds which would put a full 360 degree turn at about 10.5 seconds.

 

About the old Rhinebeck Dr1’s being so different to yours I don’t see by the specifications what could explain that your Dr1 can do a 10 s sustained turn whereas the Old Rhinebeck Dr1’s would require circa 18 s? The stated weight for the Old Rhinebeck replicas is 1290 lb (586 Kg) and they are powered by a Le Rhone. Why on earth would your machines produce such different results? Why deride them as “fat girls”?

ORA only ever had one rotary powered Dr.I.  Cole Palen, to my knowledge, was the only person who EVER flew it.  The others were all powered by some sort of radial engine.  The current Dr.I, and the one that baldeagle flew, has a 220hp continental on it which has a dry weight of 450 lbs according to wikipedia.  That is 170 lbs more than the 80 Rhone, so even if our planes where built exactly the same (which they are not), they would be 170 lbs more than mine.  There is no way their Dr.I is at 1290 lbs (the original gross weight of the Dr.I).  They are likely in the 1500-1800 lb range which would give me an extra .35 G advantage over them.

 

I see now which 5 s you were referencing to and from theoretical calculations using simply Clmax, weight and wing area a 70-80 deg/s turn rate is quite achievable. However it is erroneous to take 360/72 to arrive at 5 s because while that may be achieved theoretically (though I doubt in practice) in a spiral dive but never in what IMO could be termed a turn. However, if you looked at the Javier Arango lecture I posted earlier on they may well back in the day have called that a "turn" as he explains about the different terminology used now and then.

Agreed.  5 seconds for a 360 degree turn is an impossibility in the Dr.I, and without knowing exactly what they meant by it, it isn't even worth considering in our analysis here.

 

[Holtzauge]

4 hours ago, Chill31 said:

My airspeed indicator is always off by 10-20 mph, depending on my speed.  The faster I go, the more it is off, since my static port on the instrument dumps directly into the cockpit where the pressure decreases as speed increases.  At a given airspeed, it is consistently inaccurate though, so you have come up with the same estimate I made.

 

Watch the nose position and G loading. It is pretty consistent, but you are right, I could do better.  The speed on the GPS is not perfectly accurate either, and it has a slight lag.  Look for the lake off the nose about 2:05.  That is approximately 90 degrees off my initial heading, and the speed is already down to 45-50kts.  The rest of the turn takes 8 seconds which would put a full 360 degree turn at about 10.5 seconds.

 

ORA only ever had one rotary powered Dr.I.  Cole Palen, to my knowledge, was the only person who EVER flew it.  The others were all powered by some sort of radial engine.  The current Dr.I, and the one that baldeagle flew, has a 220hp continental on it which has a dry weight of 450 lbs according to wikipedia.  That is 170 lbs more than the 80 Rhone, so even if our planes where built exactly the same (which they are not), they would be 170 lbs more than mine.  There is no way their Dr.I is at 1290 lbs (the original gross weight of the Dr.I).  They are likely in the 1500-1800 lb range which would give me an extra .35 G advantage over them.

 

A position error of 10-20 mph in an aircraft that flies at 50-100 mph! Damn, you are lucky to still be alive!

 

On a more serious note, I assume you have a pitot somewhere to get the total pressure and using the static ports on the pitot you have or getting one that has static port and connecting those to your instruments seems like well invested money. In addition, I guess without proper static ports the accuracy of your altimeter will suffer as well?

 

About the rationale for a 10 s stationary turn time in a Dr1: I hear what you are saying about doing extrapolations from the 2:02 to 2:12 s sequence in your video but frankly I think there are to many unknowns right now given that speed was not constant and that the input is shaky since both the GPS GS you have access to is erratic and you seem to have (to put it mildly!) issues with the static input for IAS estimation. BTW where is your altimeter? Would be nice to see the horizon, altimeter and speedometer in the same frame. Tip: I recently got me a GoPro Hero 8 and you can set up a really wide field of view and the stabilization is simply superb: No shake whatsoever!

 

About Old Rhinebeck Dr1's: Check out their site info. They have 3 of them and only one with the Continental. The other two have Le Rhone engines. I will not judge their way of presenting the weights and if they are wrong or not. Anyway it does not matter that much: The weight added by the heavier Continental engine (ca 15% to the assumed T/O weight 575 Kg) is nothing compared to the power added (2.5 times more than the 85 hp you have) and the resulting deltas are as follows: Added weight adds about 3 s to turn time while the power gain cuts 6 s off giving a total gain of 3 s. So, if anything, the "fat girl" looks to be reckoned with and a 225 hp engine in a Dr1 is something I suspect most pilots in the Luftstreitkräfte would have killed for. As they say: "It ain't over till' the fat lady sings" and boy, can that gal sing!

 

Edited June 3, 2020 by Holtzauge