Salvay-Stark « Skyhopper II » mystery: NOT A Cessna!

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I found this picture by Leo J. Kohn at Krul Antiquarian Books (a true goldmine if you take the time to explore it) with the following caption: "Cessna C4, N9713Z, Milwaukee, Wisconsin."

Trouble is, not only the "C4" designation is not standard Cessna, but there is no mention of a Cessna C4, C-4 or N9713Z anywhere else, not even at Aerofiles! Closest thing I found was a Cessna 188 AgWagon with the registration "N9718V" but both aircraft have as many differences as similarities (I also enclose it below for comparison).

Whoever could help shed some light on this rare bird is very welcome to do so!!!
 

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Dear Stephane,
A beautiful find!. N9713Z looks very much like a Salvay-Stark Skyhopper, a design of 1944/1945 (the prototype flew in 1945). The company of Gene Salvay and George Stark was initially in Kansa City, KS.
(and Cessna was and is in Wichita, KS). It would not be the first time that a big manufacturer sets eyes on other designs.
Just my guess, but worthwile of further investigation.
 
I have checked the Skyhopper but unfortunately the engine configuration and cockpit are different...

The Cessna C4 seems nowhere else to be found for now, BUT... Australia's Airborne magazine online website features a list of R/C aircraft plans which includes... the Cessna C4 (plan #921, p.16, Rubber Series Scale, 724mm span, AUS$7.70). This further proves that the design must have been publicized at some point!

Source: http://www.airbornemagazine.com.au/planHome.htm
 
Dear Stephane,
please see attached photo of a Skyhopper. The colour scheme looks very similar. At least a dozen of these aircraft were built by amateur constructors and obviously there are many differences in engine cowlings and cockpit canopy shapes. I still put my 2 cents on the Skyhopper.
My good friend Johan Visschedijk (1000aircraftphotos.com) came up with following explanation for the C4 on the tail. For a brief period during the 1960s aircraft visiting the EAA Convention at Oshkosh sported such a letter/number combination on the tail. Please visit the site and look up the Coser-Oonk CO-2 (D8 on tail), the Baker Delta Kitten (P2 on tail) and there are more examples.
But why Cessna could have been involved. No Idea, so please keep digging!
Regards, Walter
 

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After examining closely your photo and the "C4" photo, I realize you are absolutely right. Not only this is one and the same aircraft type: same paint scheme, same cockpit, same engine, same wheeltrain... but looking at the Skyhopper's tail in your picture, I think I can even make out part of the Cessna logo on it....The Skyhoppers I saw before were a bit different, but then as you said, there must have been as many reinterpretations of the original design as there were builders...

We're definitely getting somewhere. Thanks!
 
Okay, things are getting clearer.

There were two separate designs, respectively called the Salvay-Stark Skyhopper and Skyhopper 2. The former was a single-seater that was marketed in 1945; the latter was a two-seat development which was marketed in 1959 (Aerofiles lists these two types as the Skyhopper 10 and 11).

The picture you provided represents the second model, the side-by-side two-seater, hence the slightly different design from the original Skyhopper. Now if this was a 1959 novelty, chances are it appeared at Oshkosh in the early 1960s, at the same time as the Coser-Oonk and Baker types you mentioned.

My two cents about it is that Salvay-Stark probably went bankrupt or out of business soon after the Skyhopper 2 was launched, and Cessna either took over the company's assets or simply purchased the rights to the Skyhopper 2. Why they never marketed it afterwards is anyone's guess, but if the "C4" picture is from Oshkosh, then it must have appeared there, not as a Salvay-Stark but as a proper Cessna.
 
After the end of World War II in 1945 there was resurgence in general aviation flying due to the great interest in airplanes. (...) A huge interest in building one's own airplane also grew in this postwar time. After the Civil Aeronautics Authority had effectively stopped homebuilt aircraft construction in 1938, leaving its regulation to the states, only Oregon passed a law permitting construction and registration of homebuilt aircraft designs. (...)

After the war, the Federal Aviation Agency (forerunner of our present Federal Aviation Administration) quickly rectified the CAA's oversight, recognizing homebuilt aircraft under a category of Experimental-
Amateur built aircraft. A homebuilt experimental-registered aircraft had to meet the 51% rule; more than half the construction had to be performed by the owner-builder. Construction had to be monitored and signed off by an FAA inspector or a Designated Engineering Representative for sound and safe building principles and practices.(...)

There were even some efforts to see who could design and successfully fly the "World's Smallest" fixed wing aircraft. (...) One of the very early homebuilt design efforts after the war was advanced by E. M. "Gene" Salvay and George A. Stark who formed the Skyhopper Aircraft, Inc. firm in 1945 in Kansas City, Kansas specifically to design a light aircraft and sell its plans to home constructors. Their "Skyhopper", design of which started in 1944, prototype NX41770 was a small, single place cantilever low-wing taildragger monoplane of mixed contruction with an open cockpit powered by a 50 horsepower engine. The goal was a plane that could be built for $1,000, and be affordable to many eager aviators in 1946. The prototype Skyhopper NX41770 first flew in 1946.

The developed revised plans-built Skyhopper I used a Continental A65 65 horsepower engine and had an enclosed cockpit, with a small built-up back and head rest fully enclosed by a small, tapered clear bubble plexiglass sliding canopy and curved low windshield. The plans version Skyhopper I single place aircraft was a handsome, well engineered design with NACA wing root airfoil 23015 and wing tip airfoil 23012. It had wide spaced fixed, short main gear strutted from the wing spars with streamlined wheel pants and a small tail wheel. (...) A two-place Skyhopper II was also offered by Salvay and Stark, by widening the fuselage just fourteen inches and using a somewhat longer wing. The A65 engine used a two-blade prop with spinner, furthering the mini-fighter image.

A number of subsequent Skyhopper amateur constructors modified their Skyhopper build using various other engines of higher horsepower. The Skyhopper design was described in a feature article in the September 1957 Vol. 6 No. 9 issue of the "EXPERIMENTER" magazine of the Experimental Aircraft Association (EAA) (...)

Source: Airport-Data.com
 
Stephane,
I think the Skhopper story went as follows:
Co-design of Gene Salvay and Geoprge Stark and started 1944 and built by the two under name Aviation Booster, Inc. .
Skyhopper: first single-seat prototype which flew on 23 March 1945 initially with 50hp engine and open cockpit. This aircraft later received 65hp Continental, canopy and raised (turtle deck) rear upper fuselage.
Skyhopper I: Reworked/improved single-seat version for amateur construction and in 1945 Skyhopper Airplanes, Inc (in Kansas City, Ks.) formed to market plans. Salvay and Stark split in March 1946, mainly since no funding could be secured (not uncommon in the immediate post-war years).
Skyhopper II: two-seater with wider cabin, increased wingspan and usually more powerful engine. Conceived in 1959. Also observed was the designation Skyhopper 2 with at least 2 examples completed in Canada.
In 1961 a Salvay-Stark Aircraft was formed in California.
Possibly in 1971 a new Salvay-Stark Aircraft Co. was started and this may have been reason for the designations Skyhopper 20 and 10 (two-seater and single-seater).
Date of first flight 23 March 1945 confirmed by Mr. Salvay in article on the Morrisey Nifty.
Since the first Salvay-Stark company started 1961, the Oshkosh visit during the 1960s of N9713Z may be more than a coincidence.
I think Cessna was never involved and as a point of interest, the Morrisey Nifty (Shin 2150, Varga Kachina etc.) was also a design of Salvay and started at the request of Bill Morrisey.
 
Thanks a lot for adding substance to the Skyhopper chronology.

You're saying that Cessna was not involved with the Skyhopper II at any point. I would like to believe you except we have two photos of the same aircraft, one given as a Cessna, the other as a Salvay-Stark. Both display the Cessna logo on its tail... What can we make of this? I don't know, but I'm not about to give it up until some explanation comes along. Thanks again, anyway!
 
Hello Stephane,

While searching the internet I came to the Cessna "C4" subject again, would like to finish this as Cessna was never involved in the subject aircraft, the two-seater Skyhopper II.
At the Krul Antiquarian Books website Cessna isn't mentioned any longer in the photo designation, and now states Salvay-Stark, alike Jane's in the 1950s and 1960s issues.
Salvay-Stark was founded by two engineers working for North American at Kansas City, soon after WW II, both moved to Los Angeles, and it was about a decade later that the Skyhopper II was built. Jane’s state Salvay-Stark in Los Angeles in the 1950s, 1960s, and early 1970s issues.
The "C4" code on the tail has been explained before, it was temporarily used during the EAA fly-inn’s during the late 1950s-early 1960s.
The kicker is that the logo on the tail isn’t similar to any of those shown at the attached photo, which shows the logos that can be found on Cessna photos and documentation from the late 1920s up to the present day.
However, a similar logo (NOT THE SAME) as on the Skyhopper II was used by Piper during the late 1950s-early 1960s, see
http://www.1000aircraftphotos.com/GeneralAv/PiperPA24.htm
http://www.1000aircraftphotos.com/PRPhotos/PiperPA-25.htm
https://highroad.smugmug.com/Airplanes/Aircraft-I-Have-Met/i-hJG7fhw
http://www.aerofiles.com/piper-pa14.jpg
http://www.aerofiles.com/pip-apache160.jpg

Assume this information is enough to close this subject.

Best regards,

Johan
 

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I don't believe that Cessna had any involvement with the first aircraft. The second plane is a Cessna Ag-Wagon crop duster.


Ray (Sitting about one mile from the Cessna plant.)
 
Johan Visschedijk said:
Hello Stephane,

While searching the internet I came to the Cessna "C4" subject again, would like to finish this as Cessna was never involved in the subject aircraft, the two-seater Skyhopper II.
Assume this information is enough to close this subject.

Sure is! Thank you ever so much, Johan, and welcome to this forum (I'm surprised you were not even a member, as I've known about and respected your contribution to the 1000 Aircraft Photos website for a long while now!).

Ray said:
I don't believe that Cessna had any involvement with the first aircraft.

Confirmed by all the answers provided. Thanks Ray!

I'm renaming this topic accordingly and moving it to the proper section. Thanks again to you all.
 
Gene Salvay worked for North American Rockwell on the Sabreliner and B-1, and was also very involved in the development of the Kfir.
 
PaulMM said:
Gene Salvay worked for North American Rockwell on the Sabreliner and B-1, and was also very involved in the development of the Kfir.

Wow. Quite a stretch from the Skyhopper to the Lancer! Thanks Paul for the info.
 
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