Push-Pull propeller combinations.

Several aircraft have been built with both a pull (or tractor)
propeller and a push (or rear) propeller aligned with each other.

Supposedly the arrangment is inefficient, yet the some of the Dornier
aircraft were record breakers.

Given that some aircraft were ruined or delayed by the problem of
combining gearboxes (He 177, Northrop XB-35 and if it ever came to it
the B-29 with its backup V-3420) it looks like an attractive
proposition.

What's going on here?

List of such aircraft:

Cessna 337 Skymaster
Rutan Model 76 Vogager
Adam A500

Dornier Wal
Dornier Do X
Dornier Do 18 Seaplane, the German PPY Catalina.
Dornier Do 26K Seaplane, possibly the longer ranged seaplane ever
built.
Dornier Do 335 Pfeil (arrow) perhaps one of the fastest piston
engined aircraft ever built.
Dornier Seawings Seastar, modern Seaplane of composites.

Savoia-Marchetti S.55
LeO H-242

On 9/2/2010 8:08 AM, Eunometic wrote:
Several aircraft have been built with both a pull (or tractor)
propeller and a push (or rear) propeller aligned with each other.

Supposedly the arrangment is inefficient, yet the some of the Dornier
aircraft were record breakers.

Given that some aircraft were ruined or delayed by the problem of
combining gearboxes (He 177, Northrop XB-35 and if it ever came to it
the B-29 with its backup V-3420) it looks like an attractive
proposition.

What's going on here?

List of such aircraft:

Cessna 337 Skymaster

I built a flying scale model of the Skymaster. Trust me, it
needed an Engineer rather than an AC Mechanic model builder. The
initial flight saw a yawing affect. I lengthened the boom a bit,
increased the horizontal stab and tightened everything up. It
flew fine after that. But, danged, was it fast. The Engines
didn't need to be sinced but it would have definately helped. I
made the mistake on the first one of putting both the same in
relationship with the body. Bad mistake. One needs to be
slightly higher. The next model had the rear elevated in
relationship to the front motor. All of a sudden, it turned into
a piece of cake to fly and danged, it got faster. I used two
different motors. The gear box idea I doubt if it would have
made much difference between a single prop and a front and rear
prop. If you have that much motor, use a heavier cutting prop.
If you don't have the power up front, add another motor in the
rear.



Rutan Model 76 Vogager
Adam A500

Dornier Wal
Dornier Do X
Dornier Do 18 Seaplane, the German PPY Catalina.
Dornier Do 26K Seaplane, possibly the longer ranged seaplane ever
built.
Dornier Do 335 Pfeil (arrow) perhaps one of the fastest piston
engined aircraft ever built.
Dornier Seawings Seastar, modern Seaplane of composites.

Savoia-Marchetti S.55
LeO H-242

On Sep 3, 12:41*am, Daryl Hunt wrote:
On 9/2/2010 8:08 AM, Eunometic wrote:





Several aircraft have been built with both a pull (or tractor)
propeller and a push (or rear) propeller aligned with each other.

Supposedly the arrangment is inefficient, yet the some of the Dornier
aircraft were record breakers.

Given that some aircraft were ruined or delayed by the problem of
combining gearboxes (He 177, Northrop XB-35 and if it ever came to it
the B-29 with its backup V-3420) * it looks like an attractive
proposition.

What's going on here?

List of such aircraft:

Cessna 337 Skymaster

I built a flying scale model of the Skymaster. *Trust me, it
needed an Engineer rather than an AC Mechanic model builder. *The
initial flight saw a yawing affect. *I lengthened the boom a bit,
increased the horizontal stab and tightened everything up. *It
flew fine after that. *But, danged, was it fast. *The Engines
didn't need to be sinced but it would have definately helped. *I
made the mistake on the first one of putting both the same in
relationship with the body. *Bad mistake. *One needs to be
slightly higher. *The next model had the rear elevated in
relationship to the front motor. *All of a sudden, it turned into
a piece of cake to fly and danged, it got faster. *I used two
different motors. *The gear box idea I doubt if it would have
made much difference between a single prop and a front and rear
prop. *If you have that much motor, use a heavier cutting prop.
If you don't have the power up front, add another motor in the
rear.


Sounds like there are a few 'tricks' in squeezing the best out of this
arrangment.

Hello
Another one, a rarity
http://www.aviastar.org/air/france/moynet_jupiter.php
Regards

On Sep 3, 3:40*am, Starshiy wrote:
Hello
Another one, a rarityhttp://www.aviastar.org/air/france/moynet_jupiter.php
Regards

Pity this attempt a safer light plane wasn't a commercial success

In message
,
Eunometic writes
Several aircraft have been built with both a pull (or tractor)
propeller and a push (or rear) propeller aligned with each other.

Supposedly the arrangment is inefficient, yet the some of the Dornier
aircraft were record breakers.

Given that some aircraft were ruined or delayed by the problem of
combining gearboxes (He 177, Northrop XB-35 and if it ever came to it
the B-29 with its backup V-3420) it looks like an attractive
proposition.

What's going on here?

List of such aircraft:

Cessna 337 Skymaster
Rutan Model 76 Vogager
Adam A500

Dornier Wal
Dornier Do X
Dornier Do 18 Seaplane, the German PPY Catalina.
Dornier Do 26K Seaplane, possibly the longer ranged seaplane ever
built.
Dornier Do 335 Pfeil (arrow) perhaps one of the fastest piston
engined aircraft ever built.
Dornier Seawings Seastar, modern Seaplane of composites.

Savoia-Marchetti S.55
LeO H-242



And the Fokker D.XXIII, of course.
http://www.aviastar.org/air/holland/fokker_d-23.php
--
Peter

Ying tong iddle-i po!

On Sep 3, 6:19*am, Peter Twydell wrote:
In message
,
Eunometic writes



Several aircraft have been built with both a pull (or tractor)
propeller and a push (or rear) propeller aligned with each other.

Supposedly the arrangment is inefficient, yet the some of the Dornier
aircraft were record breakers.

Given that some aircraft were ruined or delayed by the problem of
combining gearboxes (He 177, Northrop XB-35 and if it ever came to it
the B-29 with its backup V-3420) * it looks like an attractive
proposition.

What's going on here?

List of such aircraft:

Cessna 337 Skymaster
Rutan Model 76 Vogager
Adam A500

Dornier Wal
Dornier Do X
Dornier Do 18 Seaplane, the German PPY Catalina.
Dornier Do 26K Seaplane, possibly the longer ranged seaplane ever
built.
Dornier Do 335 Pfeil (arrow) *perhaps one of the fastest piston
engined aircraft ever built.
Dornier Seawings Seastar, modern Seaplane of composites.

Savoia-Marchetti S.55
LeO H-242

And the Fokker D.XXIII, of course.http://www.aviastar.org/air/holland/fokker_d-23.php
--
Peter


I like this aircraft, a 6500lb, 324mph speed one a pair of 520hp
engines means it matches aircraft of the same weighyt with the same
power in a larger single engine.

And the Hungarian Marton X/V looking like a sort of push pull Me 109.
http://www.whatifmodelers.com/index....c,24457.0.html

On Sep 2, 9:15*pm, Eunometic wrote:
On Sep 3, 6:19*am, Peter Twydell wrote:





In message
,
Eunometic writes

Several aircraft have been built with both a pull (or tractor)
propeller and a push (or rear) propeller aligned with each other.

Supposedly the arrangment is inefficient, yet the some of the Dornier
aircraft were record breakers.

Given that some aircraft were ruined or delayed by the problem of
combining gearboxes (He 177, Northrop XB-35 and if it ever came to it
the B-29 with its backup V-3420) * it looks like an attractive
proposition.

What's going on here?

List of such aircraft:

Cessna 337 Skymaster
Rutan Model 76 Vogager
Adam A500

Dornier Wal
Dornier Do X
Dornier Do 18 Seaplane, the German PPY Catalina.
Dornier Do 26K Seaplane, possibly the longer ranged seaplane ever
built.
Dornier Do 335 Pfeil (arrow) *perhaps one of the fastest piston
engined aircraft ever built.
Dornier Seawings Seastar, modern Seaplane of composites.

Savoia-Marchetti S.55
LeO H-242

And the Fokker D.XXIII, of course.http://www.aviastar.org/air/holland/fokker_d-23.php
--
Peter

I like this aircraft, a 6500lb, 324mph speed one a pair of 520hp
engines means it matches aircraft of the same weighyt with the same
power in a larger single engine.

And the Hungarian Marton X/V looking like a sort of push pull Me 109.http://www.whatifmodelers.com/index....c,24457.0.html

That just looks like a Speed machine. Maybe some video game like
Crimson Skies will use it someday.

On Sep 2, 10:08*am, Eunometic wrote:
Several aircraft have been built with both a pull (or tractor)
propeller and a push (or rear) propeller aligned with each other.

Supposedly the arrangment is inefficient, yet the some of the Dornier
aircraft were record breakers.

Given that some aircraft were ruined or delayed by the problem of
combining gearboxes (He 177, Northrop XB-35 and if it ever came to it
the B-29 with its backup V-3420) * it looks like an attractive
proposition.

What's going on here?

List of such aircraft:

Cessna 337 Skymaster
Rutan Model 76 Vogager
Adam A500

Dornier Wal
Dornier Do X
Dornier Do 18 Seaplane, the German PPY Catalina.
Dornier Do 26K Seaplane, possibly the longer ranged seaplane ever
built.
Dornier Do 335 Pfeil (arrow) *perhaps one of the fastest piston
engined aircraft ever built.
Dornier Seawings Seastar, modern Seaplane of composites.

Savoia-Marchetti S.55
LeO H-242

I don't know about the others but my understanding is that the
Skymaster was an attempt to design a twin engined plane that would
have the same overall dimensions as a single engine aircraft and be
safer to fly since it would eliminate asymetric thrust during engine
failure. The ironic thing is that the Skymaster safety record is no
better than a conventional twin.

On Sep 3, 10:48*am, John wrote:
On Sep 2, 10:08*am, Eunometic wrote:





Several aircraft have been built with both a pull (or tractor)
propeller and a push (or rear) propeller aligned with each other.

Supposedly the arrangment is inefficient, yet the some of the Dornier
aircraft were record breakers.

Given that some aircraft were ruined or delayed by the problem of
combining gearboxes (He 177, Northrop XB-35 and if it ever came to it
the B-29 with its backup V-3420) * it looks like an attractive
proposition.

What's going on here?

List of such aircraft:

Cessna 337 Skymaster
Rutan Model 76 Vogager
Adam A500

Dornier Wal
Dornier Do X
Dornier Do 18 Seaplane, the German PPY Catalina.
Dornier Do 26K Seaplane, possibly the longer ranged seaplane ever
built.
Dornier Do 335 Pfeil (arrow) *perhaps one of the fastest piston
engined aircraft ever built.
Dornier Seawings Seastar, modern Seaplane of composites.

Savoia-Marchetti S.55
LeO H-242

I don't know about the others but my understanding is that the
Skymaster was an attempt to design a twin engined plane that would
have the same overall dimensions as a single engine aircraft and be
safer to fly since it would eliminate asymetric thrust during engine
failure. *The ironic thing is that the Skymaster safety record is no
better than a conventional twin.- Hide quoted text -

- Show quoted text -

Possibly psychological "a single engined failure isn't dangerous so I
won't maintain the aircraft factor" and ofcourse perhaps engine
failure isn't the major cause of light plane crashes.

A single engined turbo prop is safer than a twin engine piston and
possibly even safer than a twin turbo since the pilots inabiility to
handle asymetrical thrust may be worse than his abillity to handle a
glide/crash landing.

Famously some singles have crashed and smashed through brick walls
and the pilot walked free unscathed, the engine acting as a battering
ram and protection.