Gyroscopic effect rotary engines

[Stickshaker]

It strikes me that with rotary-engined airplanes I do not notice any gyroscopic effects. I know that the SSW D.IV had a propeller rotating in the opposite direction of the engine, thereby cancelling out (most of) the gyroscopic effect, but that was not the case with, for example, the Dr.I. I could not find the gyroscopic effect in the options. Am I doing something wrong or is the effect not simulated? Or is it perhaps so benign that I compensate for it unconsciously? Perhaps one of the devs could shed some light on this.

[migmadmarine]

The extent of gyroscopic procession is that when you pull the stick back, the nose will also initially pull right, and vice versa. It is not particularly something you're battling to the extent that you might think. 

 

Also, you've fallen into a common misunderstanding about the engine of the Siemens. It is the crankshaft that counter rotates rather than the prop, the prop is still attached to the crank case. The crankshaft goes the opposite direction not to counter torque or gyroscopic effect, but in order to let the engine run at twice the RPM without the propeller running faster. Since it rotates counter to the engine, the engine can produce the higher power output of max RPM without over speeding the prop, or needing a reduction gearbox. 

[VonS]

@OP, you are probably thinking of the earlier Siemens-Halske Sh.I (nine-cylinder) rotary engine that was installed on the handsome Siemens-Schuckert D.I - on that engine, the propeller, as far as I know, was bolted to the crankshaft - while the cylinders rotated in the opposite direction (of prop and crankshaft). For the later Sh.III (eleven-cylinder) engine, the prop was connected to the cylinders/case instead, so no contra-rotation would have been visible to the eyes.

 

Same RPM principle on both engines, by the way, with shaft/prop doing 900 RPM in one direction (or only shaft on the later engine), and the other parts such as case (or case/prop on the later engine) doing 900 RPM in the other direction - for a total of 1800 RPM. Much better than the top (safe) RPM on typical WWI rotaries, of anywhere from about 1250 (early rotaries) to 1350 (later rotaries).

 

For hard-core torque wrestling, recommended instead is the Fokker V.7 experiment that never entered service (with such experimental engine mounts as the Goebel Goe.III nine-cylinder or Oberursel UR.III eleven-cylinder, for HP in the 160+ range, etc.).

 

The Goebel Goe;

it makes you go.

 

To run away -

from friend or foe.

 

Good contra-rotations to you on the Siemens-Halske,

?

 

 

Edited February 20, 2024 by VonS
Added info.

[Stickshaker]

Very enlightening; thank you! I hope the discussion will go on and provide more insights!

[Cynic_Al]

On 2/20/2024 at 9:25 AM, Stickshaker said:

Perhaps one of the devs could shed some light on this.

 

The effect that you're expecting, is calld Gyroscopic Inertia, namely a reaction at right angles to the axis of any movement of the airframe, the direction determined by the direction of rotation of the engine. For example (as applies to the planes/engines in this game), pitch-up the nose and the aircraft yaws to the right, the yawing to the right in turn generates a pitch-down moment and so on. These reactions must be compensated by the pilot. The lattter scenario is modelled to very varying degrees on the rotaries in the game, however the opposite scenario, i.e. pushing the nose down, generates no reciprocal reaction as described. Similarly yawing the airframe should generate a pitching reaction, but don't expect to see that either.  To be clear, I have been discussing Gyroscopic Inertia; Gyroscopic Precession is a different effect.

[=IRFC=kotori87]

If you're looking for a plane that is greatly affected by engine torque effects, try some of the more recent planes. I've been flying the Nieuport 17 GBR and the Sopwith Snipe recently. Both of them handle very differently in the left-hand vs right-hand turns, and rapid changes in engine speed (especially at low airspeed) will really throw them around. I am sometimes unable to turn left while pulling up into a stall-turn, I have to push my nose down a bit to get the turn started before pulling back in.

[1PL-Husar-1Esk]

On 2/20/2024 at 6:25 PM, Stickshaker said:

It strikes me that with rotary-engined airplanes I do not notice any gyroscopic effects. I know that the SSW D.IV had a propeller rotating in the opposite direction of the engine, thereby cancelling out (most of) the gyroscopic effect, but that was not the case with, for example, the Dr.I. I could not find the gyroscopic effect in the options. Am I doing something wrong or is the effect not simulated? Or is it perhaps so benign that I compensate for it unconsciously? Perhaps one of the devs could shed some light on this.

Dr.1 has it and I think it's the best example, do try  left and right turns without ruder or elevator and noticed how plane nose is moving. 

[Stickshaker]

Good suggestion, Husar! I tried it and the gyroscopic effect indeed is more subtile than I expected. So subtile, in fact, that it needs a bit of co-ordination between stick and rudder, but not (much) more that you would expect from a plane of that period.

Another issue for rotaries is throttle control. In the game,you can control power in the area whwre it counts in flight, but I have read that many rotary engines have but two positions: idle and full power. In flight you may always fly with 60% or more power, but does anyone know how this was with the WWI aircraft that we can fly?

[AndyJWest]

Stickshaker, if you haven't yet seen them, you should look for forum member Chill31's posts on flying the rotary-engined Dr1 replica he owns. He goes into a fair bit of detail regarding gyroscopic effects etc.

[1PL-Husar-1Esk]

1 hour ago, Stickshaker said:

. So subtile, in fact, that it needs a bit of co-ordination between stick and rudder, but not (much) more that you would expect from a plane of that period.

Do that fast (little dive)and  more than 60 degree of bank, you need a lot input for Dr1 to turn coordinated or even turn in direction you wish.

Edited March 8, 2024 by 1PL-Husar-1Esk

[gabuzomeu]

Stickshaker, the on/off ignition switch is called engine blip switch and you have to bind it in the engine controls section.

Then it actually cuts ignition as long as it is pressed, and , obviously, this has an effect on torque

[=IRFC=Gascan]

To my understanding, most of the early rotaries didn't have a throttle, but later ones did. Since most of the planes in the game are models from 1917-18, they all have the ability to throttle power. They also have the "blip" switch that cuts ignition.

[Stickshaker]

Thank you for all your comments! Andy: I will have a look at the forum posts.