Here is a sample of the latest letters:
On the Panther engine run:
Builder Harold Bickford writes:
“Hi William, I expect also that someone will say that a 62″ prop and 2.520 rpm shows that the Corvair can’t turn much of a prop or something along those lines. Clearly any propeller driven airplane and engine for a particular flight profile will have an optimum prop. In the case of the Pietenpol climb performance in a draggy airframe means a different prop than Dan wants for the Panther. With the Piet/Corvair combination there is an experience base to draw from with real world results by folks who’ve done the work. That trumps the “I heard that….” type of commentary which is all too common. With the Panther, Dan and you are pushing the envelope in a different direction and adding to that real world data base. The fact that conventional wisdom is replaced with actual test and performance data is the critical difference. Build, learn fly; what could be better? Harold”
Harold, When people talk about pitch and diameter, they often forget to consider blade area which varies a lot from design to design. It would be like comparing aircraft stall speeds by just looking at wing span and angle of attack, but not taking wing area into consideration. This particular prop design had a fair amount of blade area. Also HP absorption on props is not linear, its exponential. An engine putting away 90 hp at 2800 rpm will only need a prop 1/4 the size of one absorbing 90 hp at 1400 rpm.-ww
Pietenpol builder Dave Aldrich writes:
“Under the “philosophy” section of this post, you could add the Lycoming/Continental (NOT Lycosaurus, an inappropriate and inaccurate term) engines that are used on many of the new homebuilts of today, even though some are almost as old as your box and pan brake. Sometimes the simplicity and elegance of a design doesn’t need “major innovation”.
Since you bring up the subject of firearms, in my gun safe are a 1903 Springfield 30-06 (as built, though the leather sling has seen better days), a 1930′s Stevens single shot lever-action .22 (the stock is a bit loose from an encounter with an irate goat on the family farm in Indiana) and an LC Smith side-by-side 20 gauge, also from the same time frame. All 3 still function perfectly. The sad part is that none of my sons have any interest in them so at some point I’ll sell them to some one who appreciates history and quality. Given the mood of the politicians, I may have to do that soon lest it be forbidden… Sic transit gloria mundi.”
Dave, friends who have been to our place recognize that the truck in the photo is sitting on the half of our yard with a big backstop that forms our 25 yard pistol/plinking range. We are lucky to live in a rural setting, and there is nothing behind our house for several miles. The range is a neighborhood resource here. While I am concerned about firearms issues, I remain optimistic, thinking of the example of how our extreme freedom to build any kind of aircraft we like in this country has remained in place through a number of challenges. Perhaps most people understand that when we walk away from individual choice and personal responsibility, we are walking away from the defining characteristic of being an American.-ww
Builder Chris Craver writes:
“Great video William. Love it!”
Zenith 601XL Builder and Flyer Andy Elliott writes:
“My 3100-powered, highly cleaned-up 601XLb taildragger runs a 64×47 Sensenich. It butts up against the LSA limits down low at 3250 rpm (sucking gas like crazy!), and will cruise at 115 KTAS up high (say 10500) at 3050 at WOT, just under 5 GPH.
Static rpm is ~2700 depending on the conditions, which is a little on the low side, but since the plane gets off the ground in ~1000′, and as I only use 100LL and am careful about adding throttle smoothly during takeoff at low altitudes, I think it’s a pretty good cruise prop. Even so, at full throttle on the ground, I can lift the tail with the brakes locked.
I have flown in and out of a number of paved airports at >9000′ DA, and the performance has been “acceptable” as long as I keep the plane at 90 KIAS in the climb, which usually yields about 2800 rpm. Andy”
On the subject of Kitfox mounts:
Builder “PJ” writes:
“Great pictures of Vern welding. I just took the EAA Workshop Gas Welding class last week in Chesapeake VA. Cost me $329 for the 2 day class. It was a challenge learning to use the torch. We had 12 guys in a very small room with very hot torches and its amazing nobody set their eyebrows or beards on fire!”