Cessna ATPTB Twin Pusher Turboprop

[Dynoman]

Cessna developed a twin turboprop pusher as a technology testbed and I was wondering if anyone has acquired any photos of the aircraft. It was apparently seen, mostly at night, around Wichita.

 

[Dynoman]

Here is NASA's report on a piloted simulation study in connection with the aircraft.

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19940022099_1994022099.pdf

 

[flateric]

http://cessnateur.blogspot.ru/2014/10/unearthed-photo-of-cessna-atptb.html

 

[Stargazer]

Very interesting! This was originally the prototype Cessna 550 Citation II [N550C], which carried experimental c/n 686.

This particular aircraft didn't fare well as it is listed as "destroyed" on April 12, 1991.

 

[Dynoman]

Front and side views of Cessna ATPTB.

 

[Orionblamblam]

Here is NASA's report on a piloted simulation study in connection with the aircraft.

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19940022099_1994022099.pdf

Updated link:

https://ntrs.nasa.gov/citations/19940022099
Piloted Simulation Study of an ILS Approach of a Twin-Pusher Business/Commuter Turboprop Aircraft Configuration
NASA TM-4516

 

[CraigD]

This is a great thread and I was surprised to find it. I worked at Cessna Wallace Division between 1979 and 1987, in experimental flight test. I was a flight test engineer on the Citation I and II, later the Citation S/II programs for my entire time at Cessna, which means I logged a lot of flying time in N550CC. N550CC started life as the first Citation II prototype in 1977, then became the first S/II prototype in January 1984. It became the ATPTB to do research into the twin pusher turboprop configuration in 1986. The vertical tail, horizontal stab and elevator are from the Citation III.

I flew co-pilot on the first seven flights of the ATPTB, starting at the end of 1986 and early 1987. I flew it (handled the controls) some in cruise flight and I made one landing.

Here are a couple photos of N550CC in the ATPTB configuration. The landing photo is from the first flight. The inflight shot shows the original engine inlet configuration. There were oil cooling problems with that configuration, and we were not able to do any cruise performance until the inlet was modified and additional cooling flow routed to the oil cooler. The oil cooling modification was made after I left Cessna in early 1987.

 

[GTX]

That is an attractive aircraft

 

[Stargazer]

I worked at Cessna Wallace Division between 1979 and 1987, in experimental flight test. I was a flight test engineer on the Citation I and II, later the Citation S/II programs for my entire time at Cessna, which means I logged a lot of flying time in N550CC. [...] I flew co-pilot on the first seven flights of the ATPTB, starting at the end of 1986 and early 1987. I flew it (handled the controls) some in cruise flight and I made one landing. [...] Here are a couple photos of N550CC in the ATPTB configuration.

Thanks for your testimony and the beautiful photos!

 

[CJGibson]

Lovely stuff. In your time at Cessna did you ever come across any Brits who had worked for Beagle Aircraft in the UK?

Ta

Chris

 

[CraigD]

Lovely stuff. In your time at Cessna did you ever come across any Brits who had worked for Beagle Aircraft in the UK?

Ta

Chris

Hi Chris,
Sorry, I don't recall meeting anyone who had worked at Beagle Aircraft.

Craig

 

[Scott Kenny]

This is a great thread and I was surprised to find it. I worked at Cessna Wallace Division between 1979 and 1987, in experimental flight test. I was a flight test engineer on the Citation I and II, later the Citation S/II programs for my entire time at Cessna, which means I logged a lot of flying time in N550CC. N550CC started life as the first Citation II prototype in 1977, then became the first S/II prototype in January 1984. It became the ATPTB to do research into the twin pusher turboprop configuration in 1986. The vertical tail, horizontal stab and elevator are from the Citation III.

I flew co-pilot on the first seven flights of the ATPTB, starting at the end of 1986 and early 1987. I flew it (handled the controls) some in cruise flight and I made one landing.

Here are a couple photos of N550CC in the ATPTB configuration. The landing photo is from the first flight. The inflight shot shows the original engine inlet configuration. There were oil cooling problems with that configuration, and we were not able to do any cruise performance until the inlet was modified and additional cooling flow routed to the oil cooler. The oil cooling modification was made after I left Cessna in early 1987.

View attachment 771096View attachment 771097

That is a pretty aircraft!

How was cockpit/cabin noise with the pushers?

 

[CJGibson]

Hi Chris,
Sorry, I don't recall meeting anyone who had worked at Beagle Aircraft.

Craig

Thanks. I was pondering where the designers of the Beagle B.228 had ended up after the company ceased trading. The Beechcraft Starship, Piaggio Aaaaah-vanti and now the Cessna ATPTB share the same basic configuration.

https://www.secretprojects.co.uk/threads/beagle-b228.22699/
Chris

 

[CraigD]

That is a pretty aircraft!

How was cockpit/cabin noise with the pushers?

Thanks, Scott. I can't really comment on interior noise levels because we wore helmets (and parachutes) for all 7 flights I participated in. As you can imagine, the safety gear was a requirement on new airframe configurations. For the first five flights we concentrated on handling qualities at forward and aft c.g. On the third flight we also performed inflight engine shutdowns and restarts. Flight 6 was our first attempt to get to higher altitude and that was when the oil cooling problems began to limit our efforts. The 7th flight was performed after some changes were made, but there wasn't enough improvement to continue with cruise performance or high altitude stability tests.

 

[CraigD]

Front and side views of Cessna ATPTB.

Taking a closer look at the two hangar photos I noticed that there are two stall strips taped to each wing leading edge. This means that Cessna had done some stall or approach-to-stall testing to define the characteristics of the airplane at very low speeds. Also, the external part of the engine exhaust nozzle has been streamlined or re-contured. I'm not sure why unless they were trying to improve cruise speed with a little drag reduction program.

 

[CraigD]

http://cessnateur.blogspot.ru/2014/10/unearthed-photo-of-cessna-atptb.html

The inflight photo that flateric posted from the cessnateur blog is also interesting, not just due to the new engine inlet configuration. First, the pilot is not wearing a helmet, and therefore probably not wearing a parachute. The presence of the stall strips indicates that the flight was performed after stall characteristics were found to be not particularly hazardous, so the crews were no longer required to wear the extra safety gear.

Second, the stall/spin recovery parachute system under the rudder is not installed. This is even more telling, in a good way. It confirms that the general stall characteristics were conventional and recoverable with normal recovery techniques. The pair of stall/spin recovery chutes had relatively small canopies that were to be used to stabilize the airframe in the event of a loss of control during low or high-speed flight. I think there were two configurations of the chutes, a slightly larger canopy for slow speed deployment and a smaller diameter for high-speed use. There were two chutes, for redundancy, and they could be cut loose once the aircraft was under control. They were deployed from the cockpit and used a mortar charge to help ensure they deployed away from the airframe in most any situation. The chutes were originally developed for the Citation III (650) test program.

Lastly, the re-contoured engine exhaust nozzles seem to have white-painted fairings covering them.

 

[SCAT-15F]

What kind of performance did this bird have?

 

[CraigD]

What kind of performance did this bird have?

The NASA report cited in response #2 and #6, above, mention 0.6 mach and 41,000 ft. I'm not sure at what altitude 0.6 mach was achieved.

 

[SCAT-15F]

The NASA report cited in response #2 and #6, above, mention 0.6 mach and 41,000 ft. I'm not sure at what altitude 0.6 mach was achieved.

Not too shabby- faster than the CBA Vector and NAL Saras.

 

[TomcatViP]

Here is NASA's report on a piloted simulation study in connection with the aircraft.

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19940022099_1994022099.pdf

Updated download link: https://ntrs.nasa.gov/search?q=19940022099