Curtiss Pusher Model D-IV Project

[N44VY]

Gents (and Ladies?): I am new to the Aerodrome Forum, generally concern myself with Monocoupes. BaldEagle and I decided it would be good if I built a Curtiss Model D-IV (probably so he could fly one!). He caught me in a moment of sheer insanity, and off we go again! Thank goodness for two things, right off the bat - Vet Thomas and his CAD/CAM metal parts, the many turnbuckles, pulleys and the rib blanks; and the Charles Schultz Drawings available from WWI Aero, among other sources. I strongly recommend the investment with Vet (builder of the Curtiss Replica hanging in ROC International Airport) for the myriad metal fittings, pulleys, turnbuckle bits and plate fittings. You can not pay yourself little enough to make these fittings yourself. Gotta have a LOT of free time to do that! Vet's heavy rib laminating jig turns out blanks that are perfect, too.

Congrats aside, I now seek enlightenment: The Schultz drawings show wing panels with the correct camber, but indicate the total chord of the panels at 4 feet 2 inches. The wing struts are shown at 4 feet 6 inches long. In most other books describing technical details of the Pushers, the Model D is shown with a chord of 4 feet 6 inches, the same as the wing struts are tall. This makes most sense - the chord being the same as the upper and lower wing panel gap. Which is correct??

Problem two with the facts: the replica Hudson Flyer described here has massively wide ribs compared to the ribs called out by Schultz at 1/2 inch end ribs and 3/8 inch intermediate ribs. Which is most correct for a Model D? Likewise, the Hudson Flyer spars are stated as ash laminations instead of spruce and are much wider than the drawings. The ROC Pusher and the Marine Corps Museum Curtiss have spars and ribs most certainly from the Schultz drawings specifications. If fact, the Pusher Dale Crites built which hangs in MKE International also appears to have Schultz-style wing construction. Schultz reportedly used factory drawings and sketches to make his set, which lends credence to authenticity. Before I start wasting some pretty valuable spruce and ash, it would be a great help if your collective data bases could cough up something which settles this rib and spar quandry! I talked with BaldEagle about this spar of ash issue. He did a considerable amount of Wright replica building for Ken Hyde, who is known for dead certain authenticity. The Wright spars were ash in the center section and spruce in all other wing panels. That sounds like very sound engineering, to me. Who's got the real dope?

Meanwhile, here's the promise: When I get sorted correctly (with your assistance), and glue and wood bits fly, I'll post a photo record here for us all. Vet's and the Hudson Flyer photos posted here have been invaluable references for me, so I will reciprocate.

[cfgray]

Hi, November Charlie,

I've spent some time pondering Curtiss Pushers and would like to offer some random thoughts, even if they aren't definitive.

During the Pioneer Era, they were simply Curtiss biplanes, divided broadly into those with "heads" and those which were "headless."

I have not been able to find any instance of the machine being referred to at the time as, say, a Curtiss Model D-IV. That designation was invented by subsequent historians and writers and retrospectively applied to the machines. It's a matter of personal preference, of course, but I prefer to use the designations as used by the builders at the time.

When the Curtiss Company mentioned a Curtiss Model D-4, it meant a 4-cyl "Curtiss Standard Biplane," so a Curtiss Model D-8 was the 8-cyl version and the Curtiss Model D-8-75 was the 75 hp 8-cyl version.

Incidentally, the same holds true for Wright machines, there was never a Wright Model A. While Wilbur and Orville were involved, the Wright machines were all referred to as simply being variants of the Wright Fliers, usually designated by year, such as the "Wright Model 1907 Flier."

The specifications of the Curtiss machines were widely published, but were not always taken from factory-built machines. Many were built by amateur aviators and by professional exhibition aviators, often with variations.

One of the most widely circulated set of drawings and specs at the time, of the "Hayward" Curtiss, has the front elevator assembly outriggers 1 foot too short and the tail assembly outriggers 1 foot too long, meaning that anyone who built to those specs and drawings would end up with a tail-heavy machine.

The older (1909-1910) headed Curtiss machines were larger and heavier than the later (1911 and following) machines. I believe the narrower chord you cite is taken from an exhibition machine panel of the 1911 and later period, when a smaller surface area and lighter weight were sought.

As for the ribs, the thinner intermediate and end ribs were associated with the lighter exhibition machines of 1911 and later.

Regarding ash, the Curtiss chassis was ash, but the wing structure was spruce, certainly so in the 1911 and later headless exhibition machines.

I hope some of this is of value. I've been contemplating building an accurate Beachey-Eaton Biplane (1914, and not built by the Curtiss Company) for some time now, and can appreciate the myriad of questions and doubts which arise when you begin to think about selecting materials and actually cutting wood.

Best,
cfgray

[ulpilot]

I have to echo cfgray's thoughts. During my research I found that practically no two planes were built the same. Curtiss and his crew were constantly making changes to improve the basic design. Add to that were the modifcations and repairs owners and pilots made, things get confusing real fast.

Glad to see you started a thread on this. Can't wait to see pictures. And thanks for the very kind words.

Vet

[airknocker]

An example of an amatuer built pusher is at the Empire State Aerosciences Museum at the Schnectady County Airport Photo Album Viewer
Empire State Aerosciences Museum (ESAM) at the Schenectady County Airport

[N44VY]

Thank you all for the insights. What you're revealing is that I need to do a lot more research before cutting the ribs down. I have drawn up the fixture I need so I can duplicate each wing panel exactly, but gluing it together is dependent on deciding on the final chord. Recce's to Hammondsport and Owls Head Museum are in order before I cut wood, at least.

New observations for comment and clarifgication:

Eugene Ely used the Hudson Flyer for his historic landing on the USS Birmingham in 1910. That is pretty clearly validated. What is interesting is the it sppears he used parts of the Hudson Flyer on January 18, 1911 for the first shipboard landing on the USS Pennsylvania. Studying actual photos, the center section is what has to be the Hudson Flyer. It is painted (doped?) in what appears silver. All outer wing panels, including the small 30" inserts, are a much lighter color, almost clear or cream (dope?). There are two floatation tanks under the center section lower wing, just like the Hudson Flyer, as well. They appear considerably more dinged up than the ones in photos of the Hudson Flyer, but that would be expected. Has this been verified in some reference, somewhere?

More later, no doubt!

[sobrien]

The Curtiss that Ely used in Nov. 1910 to take off from a ship was the Hudson Flyer with wing mounted ailerons. The plane he used to land and then take off from a ship in Jan. 1911 was one of the first of the Model D "Swallow" tailed Curtiss'. It was a new design that borrowed nothing from the Hudson Flyer. It had a single surface front elevator and rear mounted elevator. It did have wing extensions mounted between the wing bays and it's wings were of a new design that were covered on both sides rather than just the top of the planes as in the Hudson plane.
The Schultz plans are the best available and were copied from what are believed to be Curtiss factory blueprints. The Rhinebeck Curtiss and the Curtiss Museum's Hydroaeroplane are 2 flying examples built from these plans.
I would also check out Steve Doherty's build of the Hudson Flier at the Curtiss Museum and on this forum. He is using 1911 style wings and fittings and 1910 outriggers and front and rear surfaces. It should be flying this summer. He is using a Curtiss OX engine too.
If you search the web you'll find a lot of photo of originals and replicas. Be care full though, there is a lot of mislabeling and misinformation.
I recommend checking out the WWI Aero materials list, there was a good series of articles on the "Curtiss Pushers."
Below are 2 links to photos I took of Cole Palen's first Curtiss type that was built in the late 50's using 1910-12 magazine articles and the Replica of the Golden Flyer in the Niagara Museum built using Charles Willard's drawings.

Good luck,
Sean
Cole Palen Curtiss Pusher pictures by sobrien_album - Photobucket
Curtiss Golden Flyer pictures by sobrien_album - Photobucket

[baldeagle]

CFG's list of Ely/Hudson Flyer says that it was the same airplane, modified (updated?), and that Ely continued flying it until August 1911:

1910 Hudson Flier - Page 2 - -The WORLD WAR 1 AEROPLANES, INC., AeroForum-


???




-

[cfgray]

Yes, they were the same machine, which was the Herring-Curtiss No. 7. This was an historic machine in which a number of very notable flights were made.

The Herring-Curtiss in the water (the xerox'd photo posted by Hudson Flier on the AeroForum page cited by baldeagle, above) used by J.A.D. (John Alexander Douglas) McCurdy for the 30 January 1911 Key West, Florida, to Havana harbor (almost), Cuba, flight was the Herring-Curtiss No. 9.

Best,
cfgray

Also, I want to correct an error in an above post of mine, that should, of course, read "Wright Flyer" and not "Wright Flier" - I can no longer edit that post

[sobrien]

My statement about the plane that Ely flew to and from the Pennsylvania in January of 1911 not being the Hudson Flyer was based on information from David Holcomb's Curtiss Pusher article 5 from WWI Aero no. 152, May 1996.
I found these photos online that would seem to support his info.





These show the landing, takeoff, and the Curtiss on deck after landing. Note the shape of the rear horizontal stabilizer and rear elevators. Also notice that there is no gap in the rudder to clear the rear stabilizer. It has 2 small bays inserted between the innermost and outermost wing panels. The wing panels look to have the new double surface covering and the new fittings to hold the panels and struts. The engine bay area also appears to be of a different arrangement.

Mr. Holcomb also states that it Was the Hudson Flyer that McCurdy dunked on the way to Havana. I have that picture somewhere but can't seem to find it.

I'm not an expert, but the photos seem to suggest that the aircraft Ely landed on the Pennsylvania was not the Hudson Flyer.

Sean

[cfgray]

Thanks for posting these photos.

As with many things in life, early aeroplanes are not always what they appear to be. It is important to note that the identity of a Curtiss machine stayed with it, no matter how modified it might be. Alterations to the outer wing panels, the number of wing panels, the front elevator, the configuration of the tail, things such as the tin floats seen in the photos, the engine, these did not change the machine's ID.

David Holcomb's series was a remarkable piece of work and WW1 AERO was honored to carry the series, but still, I am quite certain that the aeroplane Eugene Ely flew during his "experiments" with the USS Pennsylvania and earlier with the USS Birmingham, was the Herring-Curtiss No. 7.

It would be foolish to state this with absolute certainty, but I strongly believe it to be so.

Best,
cfgray