Do-335

[oakranger]

I have been reading up a little bit on the Do-335. Quite impressive machinery of its time. However, I wonder how are the thrust works between the two engines. Do they work together by running on the same % thrust given by the pilot? Or does the anterior engine gives 80% thrust while the posterior engine gives 75% thrust. I understand that the anterior practice on the "pull" motion while the posterior practice on the "push" motion.  Just wondering how they work together in that setup.

[Ack-Ack]

I have been reading up a little bit on the Do-335. Quite impressive machinery of its time. However, I wonder how are the thrust works between the two engines. Do they work together by running on the same % thrust given by the pilot? Or does the anterior engine gives 80% thrust while the posterior engine gives 75% thrust. I understand that the anterior practice on the "pull" motion while the posterior practice on the "push" motion.  Just wondering how they work together in that setup.

I'm guessing they operate at the same power settings.

ack-ack

[MK-84]

I'm guessing they operate at the same power settings.

ack-ack

Wouldnt the thrust generated still be different due to the location of the props?

[MachFly]

I assume it should be the same. I don't see a reason to run those engines at a different power settings.

[oakranger]

Wouldnt the thrust generated still be different due to the location of the props?

Both engine are the same from the information I read (Powerplant: 2× Daimler-Benz DB 603A 12-cylinder inverted engines, 1,287 kW, 1,726 hp (1,750 PS) each) hoping that somebody will answer that question.

I assume it should be the same. I don't see a reason to run those engines at a different power settings.

I would guess that both engines respond to a single throttle control. 

[mthrockmor]

Engines rotated opposite so torque didn't 'auto-gyro' them into the ground?

Boo

[oakranger]

Engines rotated opposite so torque didn't 'auto-gyro' them into the ground?

Boo

Never thought of that, thanks for sharing on that fact of information.

[MachFly]

I would guess that both engines respond to a single throttle control.  

That can't be right. If you need to throttle down one of the engine for what ever reason you need a have the capability. Just like all 2 engine aircraft of the time it's supposed to have 2 throttle levers, 2 prop pitch levels, and 2 mixtures levels.
Most of the time the engine will run at the same power settings but what if one of the engines starts overheating and you need to reduce the power. You can have two things to do that, direct control of each engine or an advanced computer that was capable of it. 190 had a mechanical computer that would do that but if wasn't very precise, when flying in formation it was not easy for them to set the power the same way. I'm not aware of any other aircraft of that time that had one throttle level. 

[wells]

There were two sets of engine controls, like any other multi-engined airplane.  The rear propeller was smaller ( 3.3 m vs 3.5 m ), presumably due to ground clearance considerations.  The airplane had greater performance on the rear engine than the front engine ( single engine flight ).  There are a couple of reasons for this,

A.  No additional drag over the airframe from the propwash
B.  Airflow entering the prop is slowed somewhat from airframe drag, resulting in greater thrust at any given speed

see "Wings of the Luftwaffe" by Eric Brown

[oakranger]

There were two sets of engine controls, like any other multi-engined airplane.  The rear propeller was smaller ( 3.3 m vs 3.5 m ), presumably due to ground clearance considerations.  The airplane had greater performance on the rear engine than the front engine ( single engine flight ).  There are a couple of reasons for this,

A.  No additional drag over the airframe from the propwash
B.  Airflow entering the prop is slowed somewhat from airframe drag, resulting in greater thrust at any given speed

see "Wings of the Luftwaffe" by Eric Brown

Ah, you gave the answer I was looking for. Makes sense now.

So, both posterior and anterior engines are the same, but the posterior had greater performance for the two reasons?

[wells]

This is strictly from a theoretical standpoint, but,

With both engines running, the front propeller probably gives more thrust, and the proportion will vary with speed, becoming almost equal at high speeds.  This is because the rear propeller is operating in the propwash from the front propeller.  Calculations give the following at sea level,

Static conditions ( 1375 hp )
front propeller ~ 46300 N thrust ( 62.5% )
rear propeller ~ 27800 N thrust ( 37.5% )

360 mph ( 1375 hp )
front propeller ~ 10020 N ( 50.4% )
rear propeller ~ 9850 N ( 49.6 % )

Greater performance was reported from the rear engine, when the front engine was shut down, as compared to the other way around.  To what degree, I don't know.

[BaDkaRmA158Th]

I read that early 335 models were prone to very high vibrations, i cant remember how they fixed it,but they did. And the aircraft was able to be made into a useful tool for its time.


For the size weight and firepower it could have, the dang thing was faaast.

[lyric1]

I would guess that both engines respond to a single throttle control. 

Not Sure it looks like two bottom left corner?

http://www.warbirdphotographs.com/LCBW10/Do335_V3-78af+s.jpg

http://www.luftwaffephotos.com/ldo3355.htm

[Seadog36]

Not Sure it looks like two bottom left corner?

http://www.warbirdphotographs.com/LCBW10/Do335_V3-78af+s.jpg

http://www.luftwaffephotos.com/ldo3355.htm

Interesting website lyric

[MK-84]

This is strictly from a theoretical standpoint, but,

With both engines running, the front propeller probably gives more thrust, and the proportion will vary with speed, becoming almost equal at high speeds.  This is because the rear propeller is operating in the propwash from the front propeller.  Calculations give the following at sea level,

Static conditions ( 1375 hp )
front propeller ~ 46300 N thrust ( 62.5% )
rear propeller ~ 27800 N thrust ( 37.5% )

360 mph ( 1375 hp )
front propeller ~ 10020 N ( 50.4% )

Awesome, thats exactly what I was wondering
rear propeller ~ 9850 N ( 49.6 % )

Greater performance was reported from the rear engine, when the front engine was shut down, as compared to the other way around.  To what degree, I don't know.