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Re: Strange 170
Posted: Fri Jan 30, 2015 3:11 am
by pojawis
From Wikipedia, for what it's worth:
Model 309 and 319
Between 1951 and 1955 Cessna used modifications of the 170 and its derivative, the U.S. Army L-19, as test beds for Boundary layer control research, under contract to the Office of Naval Research and the Army Transportation Corps,designating them as the models 309 and 319. The project was done in conjunction with the University of Wichita which conducted extensive wind tunnel tests of the concept. The model 309 utilized the German WWII Arado lift-increasing system in which a jet pump inside the wing sucked in stagnant air from the flap area, energized it and blew the higher-speed air over the ailerons. Various chemicals and enhancements were used to power the jet pump. Better results were obtained by departing from the Arado jet pump method and using an engine-driven generator to power electric motors driving axial fans to move the internal air.[3] This concept was adopted on the Model 319 but substituted an engine-driven hydraulic pump to drive hydraulic-powered axial fans. This model was more successful and resulted in the highest lift capacity, as measured by the maximum lift coefficient recorded up to that time. The 319 demonstrated the capability of taking off in 190 ft (58 m), landing in 160 ft (49 m) and clearing a 50 ft (15 m) obstacle in 450 ft (137 m). The aircraft had a stall speed of 28 kn (52 km/h).[3] The 309 and 319 were meant to be research aircraft only, and no plans were developed to incorporate boundary layer control technology in then-current Cessna models. An adaptation of the concept, used only to improve landing performance, was incorporated in U.S. cold war fighter planes like the USAF F-104 and multi-service F4.[4]
Does not do much to explain the control surface and flap configuration depicted in the advertisement, however.
Re: Strange 170
Posted: Fri Jan 30, 2015 4:03 am
by blueldr
I think that "Boundary layer control" stuff was talked about in the book "Csssna, Wings For The World". By Bill Thompson.
Re: Strange 170
Posted: Fri Jan 30, 2015 1:16 pm
by crwrpmr
I had the pleasure to fly Kelly Johnson's masterpiece, the CF 104 for 6 years.
It had two flap settings, takeoff and land. Land flap had BLC which used hp air off the compressor to blow on the flaps from the flap hinge.
Approach speed flapless was 230 kts and touchdown was 195 kts. With land flap and BLC the approach speed was 170 kts and touch down 155 kts. I last flew the aircraft in 1986 and remember it as if was yesterday. She was a beauty.
I was interested to see Cessna and the 170 was used in the development of the concept. Thank you Aryana for this post.
Re: Strange 170
Posted: Fri Jan 30, 2015 1:27 pm
by bagarre
Are those speeds correct?
Did it have split flaps like the photo?
Re: Strange 170
Posted: Fri Jan 30, 2015 1:49 pm
by crwrpmr
The 104's wingspan without tip tanks was 22 feet. The ailerons and flaps were actually rather small.
Some of the super 8 video of my era flying it in Germany are on YouTube. In some footage you can see the ground crewman checking the BLC airflow on the flaps when they are in land flap position. He's feeling for uniform airflow. If the airflow on the flaps is different you would get a rolling moment.
If interested, search CF 104 castle tour or 441 squadron on you tube and you may find some old footage.
Re: Strange 170
Posted: Fri Jan 30, 2015 2:04 pm
by GAHorn
I have a couple of Citation-X clients from Austria who flew 104's in the Luftwaffe and they speak very fondly of that aircraft (but mention that Germany lost a lot of guys trying to use it at low altitude.)
Re: Strange 170
Posted: Fri Jan 30, 2015 2:11 pm
by bagarre
crwrpmr wrote:The 104's wingspan without tip tanks was 22 feet.
I completely mis-read that and thought you were talking about flying the Cessna test plane that had BLC.
Re: Strange 170
Posted: Fri Jan 30, 2015 3:30 pm
by hilltop170
I'm not positive but I heard somewhere the 170 BLC airplane had a turbine engine inside the cockpit to power the blower for the high pressure air. That hole in the side of the fuselage would probably be the turbine exhaust.
Re: Strange 170
Posted: Sat Jan 31, 2015 3:30 am
by wingnut
Aryana wrote:Whoa, that certainly explains the oddity in the fuselage and also why that plane would be pictured on this advertisement. That must have been LOUD in the cabin, wow.
So do you guys think this flap configuration is just someone dreaming on paper or could there ever have been an actual aircraft built with them?
If you got the money, I've got the time. With a 206 wing platform, it would not be a huge leap to replicate what is illustrated in that old advert. Come on Arash, a man with your means, and especially your spirit, we could do it. It only requires a team effort directed toward a common goal, and $$$.
Re: Strange 170
Posted: Sat Jan 31, 2015 3:44 pm
by lowNslow
Maybe a 27% version?
Re: Strange 170
Posted: Sat Jan 31, 2015 7:26 pm
by GAHorn
The airplane actually was developed and flew but was experimental only, never production.
The U.S. Army decided to use helicopters instead.
Re: Strange 170
Posted: Tue Feb 03, 2015 3:02 am
by N4281V