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Collin
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Posted Wednesday, August 3, 2011 @ 11:39 AM
I started a tread on the S-5.
It looks like a RF5 with RF5B wing and it's own front section
http://1000aircraftphotos.com/Contributions/SmithRon/10714.htm
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Collin
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Posted Wednesday, August 3, 2011 @ 11:40 AM
Super Quiet Sportavia S5 (The S5 was an experimental quiet aircraft version of the RF5 for the
German government. It had a 115hp (?) Lycoming driving a wide chord
three blade propeller. The exhaust was led in large boxes down the sides
of the cockpit, cooled and exhausted upward aft of the rear cockpit. It
was a fine looking aircraft and spookily quiet when flying. Was built
spring 1971 and flew in the summer )
Sportavia S5 Lycoming Engine
S5 in the back ground
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Collin
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Posted Wednesday, August 3, 2011 @ 12:02 PM
And in the air...
Bob
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Collin
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Posted Wednesday, August 3, 2011 @ 01:41 PM
Note the exhaust exits on side.
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Collin
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Posted Wednesday, August 3, 2011 @ 02:34 PM
Hello,
Hear is a note from Johan (1000aircraftphotos)
Gentlemen,
The series aircraft was indeed known as the RF-5, however, the aircraft in photo 10714 was, as stated in the remarks, a modified research aircraft with the designation ‘S-5’. The designation was used in Flight International and D-EAFA was also registered as such. The construction number V1 (Versuchsflugzeug 1, trails aircraft or prototype) adds to this.
Registration D-EAFA
Aircraft Type Sportavia S-5
Construction Number V-1
Registration Date 05.71
Cancelled 1979
Fate Perm exp 28.02.79
Therefore I believe the designation is correct.
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Donald
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Posted Wednesday, August 3, 2011 @ 03:12 PM
Fascinating. It was the exhaust tunnels in the monochrome factory pictures that piqued my interest. From what looks like pipe clamps in the upper tunnel I presume the exhausts ran there exiting aft of the cockpit and the engine cooling air through the gills over the leading edge roots. I imagine the exhaust tunnel outer covers were sheet metal and not wood.
What happened to it? Was it destroyed or is it still around somewhere?
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Ron Smith
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Posted Thursday, August 4, 2011 @ 04:47 AM
Actually, I believe (am pretty certain) that the side louvres are there to exhaust the general cooling airflow from the engine bay. The exhaust itself is routed down the metal-lined channel on the cockpit sides and mixed with cold air via the fuselage side intake, situated just behind the engine bulkhead, before exiting about 45 degrees upward from the rear section of the side duct, just aft of the rear cockpit. That is why there is metal lining on the sides of the fuselage in the assembly photos. I remember being shown this at the time by Herr Schliewa. This was all designed for maximum silencing and reduced IR signature. I used to have a contemporary data sheet showing the measured noise levels of the aircraft (less than a K-7 glider with the airbrakes out) - I haven't seen this recently, and we are talking 40 years ago. I will have another look for it and see if I can turn it up.
Ron
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Collin
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Posted Thursday, August 4, 2011 @ 01:03 PM
Hi,
Another picture of the S-5 with Herr Putzer looking into rear cockpit. (Ron Smith Photo)
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Bob Grimstead
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Posted Thursday, August 4, 2011 @ 02:05 PM
Well, well, well!
So René Fournier and Sportavia, responsible for so many good airplanes, also made the first-ever stealth aircraft!
I'll bet it had a pretty low radar signature too.
And it would have been easy to make it remote-controlled.
I wonder if it is even now flying unnoticed and un-manned over Libya?
Yours, Bob
-------------------- Flying and displaying Fournier RF4Ds VH-HDO and G-AWGN, building replica RF6B G-RFGB and custodian of RF6B prototype F-BPXV
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Jorgen
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Posted Thursday, August 4, 2011 @ 04:32 PM
Fascinating!
Of course, since Lockheed didn't have a woodshop to make really stealthy aeroplanes, they had to make their U-2 out of metal and we all know what happened: the russians heard it coming, flipped on their radars and shot it down.
On the second picture in this thread is evidence Sportavia knew the RF 5's were a bit nose-heavy, but the added tailweight looks a little non-stealthy, don't you think?
Thank you Ron for giving us first hand information from the Sportavia plant, most interesting!
May the 4's be with you/ Jörgen
[Edit by Jorgen on Thursday, August 4, 2011 @ 04:35 PM]
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milnerd
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Posted Thursday, August 4, 2011 @ 04:44 PM
This was the US program to develop ultra quiet airplanes using glider airframes as the basis for the airframe. The program started in 1968 so I think it pre-dates this program. Check out : http://www.wmof.com/yo-3a.htm or Google Quiet Star
It had a very slow turning propeller and an enclosed exhaust all the way back to the tail. the engine was surrounded by noise attenuating blankets. One of them was for sale very recently. By all accounts it is very underpowered and needs a 5000' runway to operate out of and it tends to overheat on the ground. It seemed as though the Army did the typical "let a committee design a racehorse and you will end up with a camel" on equipment which contributed to the high weight. Still it is very cool looking and I would love to have a go at flying one!
About 8 years ago I was taxing out at Elmira in upstate New York, the home of the Schweizer factory, and a slate grey Quiet Star looking airplane with pale grey stencilling all over it (obviously a military scheme) taxi'd out behind me. It was larger than the Quiet Star and I think it had a turbo prop but it looked very much the same - a motorglider looking beast with a very large bubble canopy.
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milnerd
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Posted Thursday, August 4, 2011 @ 05:07 PM
This was the US program to develop ultra quiet airplanes using glider airframes as the basis for the airframe. The program started in 1968 so I think it pre-dates this program. Check out : http://www.wmof.com/yo-3a.htm or Google Quiet Star
It had a very slow turning propeller and an enclosed exhaust all the way back to the tail. the engine was surrounded by noise attenuating blankets. One of them was for sale very recently. By all accounts it is very underpowered and needs a 5000' runway to operate out of and it tends to overheat on the ground. It seemed as though the Army did the typical "let a committee design a racehorse and you will end up with a camel" on equipment which contributed to the high weight. Still it is very cool looking and I would love to have a go at flying one!
About 8 years ago I was taxing out at Elmira in upstate New York, the home of the Schweizer factory, and a slate grey Quiet Star looking airplane with pale grey stencilling all over it (obviously a military scheme) taxi'd out behind me. It was larger than the Quiet Star and I think it had a turbo prop but it looked very much the same - a motorglider looking beast with a very large bubble canopy.
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Jorgen
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Posted Thursday, August 4, 2011 @ 05:37 PM
Dave,
thanks for that information and I apologize for making fun of Lockheed, I bet they could have skunked up a wooden aeroplane if they wanted to. To me the thought of Fourniers or motorgliders in a semi-military role is a new one and to be honest nothing to make fun of. I guess lightness and low power, a trade mark of highperforming motorgliders combines poorly with loading the airframe up with heavy electronic surveillance gizmos.
May the 4's be with you/ Jörgen
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Collin
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Posted Tuesday, August 23, 2011 @ 03:34 PM
Another great picture from Ron Smith
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Jorgen
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Posted Tuesday, August 23, 2011 @ 04:56 PM
Thanks Collin,
great picture of a very interesting aircraft! At the risk of beeing accused of unauthorized access to classified information, does anyone know the radar signature of a Fournier? Ron, if you find a data sheet of the S-5 noise levels, maybe you could "leak" information of the radar signature too?
May the 4's be with you/ Jörgen
[Edit by Jorgen on Tuesday, August 23, 2011 @ 04:57 PM]
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Ron Smith
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Posted Wednesday, August 24, 2011 @ 05:03 AM
I have so far failed to find the noise data.
At the time, the emphasis was strictly on it being a quiet aircraft, although I would have expected the cooled exhaust boxes to have also benefited the IR signature. As far as I know, radar cross section was not a design driver (no fancy shaping or radar absorbing materials).
Ron
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Jorgen
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Posted Wednesday, August 24, 2011 @ 04:44 PM
Thank you Ron,
if anything turns up I think it would be very interesting. I expect Fourniers to have a low radar signature as it is because of the wooden construction, just curious if there are any data on it out there somewhere?
May the 4's be with you/ Jörgen
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Ron Smith
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Posted Thursday, August 25, 2011 @ 04:48 AM
Generally agree, but radar would very likely see metal components through wood or fibreglass (engine, undercarriage, etc). Canopy openings often form resonant cavities and are often metalised (thin transparent deposition) if you really need to keep the radar out. Radars never had a problem seeing my Jodel (wooden and no transponder).
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Dan Rihn
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Posted Saturday, August 27, 2011 @ 10:17 AM
In 1980 I was involved with the development of a RADAR system to track aerobatic aircraft at the 10th World Aerobatic Contest held that year at Oshkosh WI. We did have some concerns about tracking the all wood French CAP aircraft. In the end we could acquire and track them just as well as the all metal Zlin Z-50, Laser or Pitts type aerobatic aircraft.
Having worked for Northrop (now Northrop Grumman) for 34+ years let’s just say that I’ve been involved with a few low RADAR Cross Section (RCS) projects. Wood structure in itself does have a lower RCS than say a metal one but you can see it and with all the other components especially a turning propeller or an engine it’s really not a problem to see it.
Dan
[Edit by Dan Rihn on Tuesday, August 30, 2011 @ 03:49 PM]
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Jorgen
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Posted Saturday, August 27, 2011 @ 02:42 PM
Thanks Dan and Ron,
nice and discreet leaking. Sorry Dan, I don´t quite follow the last, classified sentence of your post- typo?
I guess wood is visible to a modern radar, but maybe it depends on the settings the radar is in (birdfilter, transponder only, etc).
May the 4's be with you/ Jörgen
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Dan Rihn
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Posted Tuesday, August 30, 2011 @ 03:50 PM
sorry....bad typing on my part....I edited the post.
hope it makes more sense now.
Dan
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Bob Grimstead
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Posted Monday, August 31, 2020 @ 11:59 PM
Hello Fellow Fournicators. These photos are from Graham Clark, the chap who generously and voluntarily devoted his time to translating René's autobiography from French into English. If you want an electronic copy of René's book e-mailed to you, contact him at: cgraham978@aol.com
He says, 'I took these photos (two are of pictures) of the Sportavia S5 recently at a museum not far from Hannover, where the aeroplane now resides'.
It has a massive exhaust system and was a low-level 'sniffer' research aeroplane for the German Army. D-EBUC. The side-mounted silencer is located above the wing root to dampen noise and vibes sent down to the ground. I think the elongated bulge along the rear right lower fuselage is also part of the exhaust system.
I believe the idea behind its construction was based on the fact that more than 30 percent of Germany is cloaked in forest, which provides much cover for infiltrating enemies. So a low-level super-quiet aeroplane equipped with suitable sensors (e.g. diesel fume sniffers?) could cover a wide amount of territory quickly. Dahlemer Binz (Sportavia Factory) is right on the edge of the Ardennes Forest (Battle of the Bulge, 1944/5).
Since then, of course satellite sensing technology will have solved the military problem.
I think that the museum probably still has its wings in store. Plenty of volume for extra trans-Pacific fuel?
-------------------- Flying and displaying Fournier RF4Ds VH-HDO and G-AWGN, building replica RF6B G-RFGB and custodian of RF6B prototype F-BPXV
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Bob Grimstead
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Posted Saturday, September 12, 2020 @ 10:01 PM
Graham reports that D-EBUC is at:
Luftfahrtmuseum Wernigerode
Gießerweg 1
38855 Wernigerode
Germany
Telefon: +49 (0)3943 633126
E-Mail: info@luftfahrtmuseum-wernigerode.de
-------------------- Flying and displaying Fournier RF4Ds VH-HDO and G-AWGN, building replica RF6B G-RFGB and custodian of RF6B prototype F-BPXV
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