"Aviation is fine as a sport. But as an instrument of war, it is worthless."
— General Ferdinand Foch, Professor of Strategy, Ecole Superiure de Guere, 1911
October 24, 2007
Awaiting arrival of original factory drawings to get started, GLee UL version was good for scaling figures but, not much else for this application. Plan is to accurately input the originals into Rhino in order to "build" her in cyberspace and get a 3d picture.
Have to look at Skybolt, Pitts, Hatz and, others to see what to do about wing structures. Want to do all Al. skeleton for the wings If I can but, wood not yet fully ruled out. Must remember to dig out my references next trip to Appaloosa. Aerodrome forum was productive for additional reference material.
Received Vickers mini datafile, Lewis still pending.
October 26, 2007
Have noted that the Skybolt, Pitts, Hatz and particularly the 1 1/2 Strutter in the
November 3, 2007
Continued wait on delivery of factory drawings and reference library. Review of factory originals for Pup and 1 1/2 Strutter in the meantime. Coming to conclusion that these aircraft are all variations of same design. Could extrapolate Baby from the others but, want to see float design / struts on original.
Wing structure material choice issue not yet resolved. Favor wood for ease of construction / authenticity issues but, Al. not ruled out for dimensional / environmental issues. Suspect key may revolve around environmental issues. Confident answer will reveal itself in time.
Note to self: Review Gougeon Brothers text regarding expected dimensional changes for a given humidity in terms of % of change.
Addendum:
Have made today initial stab at target gross weight of 1,270 lbs. Basing this in comparison to original specifications in Datafile for the 130hp Clerget Baby, with a full military load weighing in at 1,742 lbs and the following calculations / assumptions.
Calculated stall speed of 130 hp Clerget Baby @ gross weight = 35 mph. Further assumptions.... 174.2 lbs = 10% (arbitrary) weight reduction from original gross for use of modern materials. 267 lbs = Reduction of "Military Load."
Desired stall speed of replica baby = 30 mph
November 6 , 2007
Have noted reference Nov 3rd entry, faulty reasoning on two accounts.
- Cannot assume weight reduction utilizing modern materials.
- Extrapolation of gross wt via desired Vsl likely not viable.
Basis for this new revelation on observation of two long established full scale WWI replicas utilizing 4130 tube fuselages and wooden wing structures. One a Nieuport 17 and the other a Fokker Dr.1. In both cases, significant gains in empty weight over the original specifications have been realized in the following percentages....
Model Original empty weight Replica empty weight Percent gain
(Redfern) Nieuport 17 827 lbs 1,004 lbs 17 %
(Sand's) Fokker Dr.1 895 lbs 1,150 lbs 22 %
Noted further is how above gains for the replicas are without "military load."
Based on this empirical evidence I must adopt the original gross wt for the 130 hp Clerget Baby and calculate all structures for 1740 lbs.
November 9, 2007
After consulting design texts and concurrent with observations of Nov 6, now fully versed in and keenly aware of the "design weight spiral." Question now is not whether weight gain will be realized but, by how much? The two existing published examples are suggestive of an average 20% but, are too small of a sampling for accuracy. However, the following weight savings over the 130hp Clerget original are more certain......
130hp Clerget dry weight 110 hp Rotec Radial Weight Savings
381 lbs 224 lbs 157 lbs
Reduction of military load 267 lbs
= 424 lbs
The necessity of CAD model comparison (with assigned densities of materials) between original airframe structure and proposed 4130 design changes is paramount to the decision regarding wing structures. The Svoboda Sopwith 1 1/2 Strutter and the Storo Bristol F2b are suggestive of success but, are private designs without published results.
November 17, 2007
Arrival yesterday of long anticipated original Sopwith drawings. Have noted that these include a mixture of the Schneider trophy winner as well as the later versions.
Of particular interest are the float details which reveal obvious design deficiencies as compared to modern standards. Wing structures and fuselage are typical aside from an interesting departure from equidistant rib spacing.
An interesting dilemma regarding the weight spiral is revealed in that the original propeller diameter is a massive disk of 104". The Rotec R2800 has a recommended prop diameter of 76" and the R3600 is 84". Along with the 4130 tubing airframe and probable higher lift airfoil sections, the ramifications are obvious. Will be in better position to deal with these issues once the aircraft is built as per original specs in 3d. Due to personal time constraints, I anticipate as much as a year to do this.
It is with the floats then that I will start my CAD work. Inputing the details of the 1915 drawings will reveal areas for improvement in consultation with texts and more modern float design plan-sets.
December 8, 2007
Preliminary CAD work on main float confirms prior suspicions regarding required internal structural design improvements. Original canvas bulkheads are an obvious start along with rib structure. Modern compartmentalization is assured. Of issue now is whether or not to maintain external authenticity in favor of a new stepped bottom profile and propeller spray considerations.
December 22, 2007
Continuing questions regarding floats and water operations in general. Slow progress on CAD work. Original design used confusing and (no doubt) mass production adverse, internal load transfer structures. Have joined Seaplane Pilots Association (SPA) in effort to increase education. Ordered design text referenced by Peter Bowers, (Seaplane Design, by William Nelson, McGraw Hill Book Co., 1934 edition).
