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  1. V

    Water Injection for Industrial V-Twins

    Power levels above OEM come with an increasing risk of failure. But, for whatever reason, people want to consider /talk about flying with absurdely high specific power.
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    What aviation news, blogs or e-mail newsletters do you actively read?

    ”Friends and family” of the employees of magazine ad departments? 😁
  3. V

    Water Injection for Industrial V-Twins

    If we are talking now of using water for more than charge cooling and want power augmentation, maybe nitrous oxide has a place. One switch could open the solenoid to the nitrous bottle, the flowing gas then brings in water and methanol in the right proportion. Methanol for fuel, nitrous for...
  4. V

    What aviation news, blogs or e-mail newsletters do you actively read?

    Kitplanes, EAA magazine, Aviation Consumer, sometimes I page through the AOPA magazine they send me. Online: HBA, Sonexbuilders.net
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    best 100 HP auto/motorcycle engine conversion?

    The Goldwing/Silverwing, etc water cooled engines? I remember a Contact article by someone converting one to acft use ( was planning to use a VW Rabbit wheel bearing as a prop bearing, or something' like that). The engines are very smooth and well made, but his conversion ended up quite heavy...
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    Nikasil Cylinders

    I was under the (mistaken?) impression that the good Nikasil cylinders underwent some specialized processes to assure the oil still worked on the surface, that it was of an appropriate bhardness, that it stayed bonded to the AL, etc. It would be worth exploring the materials and processes used...
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    Very low aspect ratio planes?

    It would. The PAV study makes a good case for the practicality of the form, for the right application (just like many other layouts. Horses for courses.)
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    Very low aspect ratio planes?

    For this purpose, as implemented in the Facetmobile, the advantages over a more conventional (higher AR) design would be: 1) A relatively large wing area with low structural empty weight. This allows for a low stall speed (despite the lack of high lift devices and possibly a lower Clmaxl). 2) A...
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    Very low aspect ratio planes?

    This is just nonsensical now, sorry. A key takeaway: Use a well maintained 4stroke and reduce the likelihood of any of this in the first place.😁
  10. V

    Very low aspect ratio planes?

    Yes, this "falling leaf" exercise is a good way to get familiar with footwork near the stall. I've done it a bit in the C-152, and IIRC the descent rate was about 650 fpm. So, it would be tough on the airplane to hit at that speed (about like a dead drop from a few feet up), but could be the...
  11. V

    Very low aspect ratio planes?

    Let's talk about the C-152 specifically, then. I don't know where 30 MPH comes from, but yes, I would definitely try to max perform the wing (that is, keep it very near its critical AoA) as I approach a touchdown at/near stall speed. And there's enough elevator authority to accomplish that (as...
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    Very low aspect ratio planes?

    Couldn't you do that in any plane?
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    Pusher verses tractor propeller

    Apache I was surprised when I learned that the FAA sets >no< minimum SE climb gradient for certified twins weighing 6000lbs or less. It’s “legal” if they can’t even maintain altitude on one engine. For those more than 6000 lbs and type certified (not built) after Feb 1991, the minimum climb...
  14. V

    Very low aspect ratio planes?

    An aside: Those CAFE reports are great, it is unfortunate the work was discontinued. An example of really useful data collection and analysis. They caught some fairly significant misstatements in published acct performance data, too. IMO, the CAFE work/reports are the kind of thing to which...
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    Very low aspect ratio planes?

    Thanks for the attachment, great stuff. At those extreme AoAs, drag becomes very high. That's why we see L/D of 2 at these Cl (Figure 5). If we are at 30 deg AoA (and achieving those Cl) we're either carrying a lot of power or we are coming down at a steep angle.
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    Pusher verses tractor propeller

    That's true (Pops has some Skymaster time and says the same thing). The Cessna design team members say that this shouldn't be attributed to differences in prop efficiency between the front and rear engines, but due to parasite drag differences. With the rear prop running, the low pressure zone...
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    Very low aspect ratio planes?

    Why would an increase in the Facetmobile's weight have an appreciable impact on its cruise performance? Increased weight has zero impact on parasite drag. At cruise speeds, drag due to lift is minimal, so even a substantial % increase due to weight still yields only a small increase in the...
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    Pusher verses tractor propeller

    BJC, Sorry, you asked for data, and I have no numbers to add to the timeless tractor vs pusher debate. But: As you qualified it: a data point. Could the plane's inability to climb be strictly the result of aero drag and not related to prop efficiency? I'd think that a gear leg upstream...
  19. V

    Very low aspect ratio planes?

    My caveman technique would be to take a few of these planes with numbers you trust (Zimmerman, Hoffman, etc), plug the minimum level flight speed, wing area, and aircraft weight into the lift equation to determine the Cl under those conditions. The prop thrust will bias things a bit, but...
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    Very low aspect ratio planes?

    I don't know if this helps, but Dr Wainfan's Facetmobile Home Page says that plane weighs 740 lbs max, has 207 sq ft of wing area, and that it doesn't stall, but: A 740 lb airplane with 207 sq ft of wing area requires a Cl of 1.0 for level flight at 33 kts, standard day.
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