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  1. V

    Harbor Freight Predator 670 V-Twin Horsepower tests

    Hey, a little buck converter on the drill's 20v battery could power all kinds of 12v stuff in the JMR. Take care, Pops! Spring and better weather is on the way, rest up for a bit.
  2. V

    Boeing - Design Issues...

    Yeah, and I'm not sure Boeing is responsible for a wheel coming off a plane, or a seat adjustment switch being activated. There's now a lot of reporting that is just "airplane news" that is getting framed as 'negligent Boeing news'. I'm not saying they are perfect (far from it) or that the...
  3. V

    Jabiru 3300 fuel burn

    Not specific to the Jabiru, but most air cooled pushrod airplane engines with carburetors have a BSFC of somewhere around 0.42 lb/HP/hour. So, going by that, if we want 70% power from a Jabiru 3300 (120 HP x 0.70 = 84 HP) we should expect to burn about 35 lb per hour = about 5.8 GPH. If the...
  4. V

    Harbor Freight Predator 670 V-Twin Horsepower tests

    I've got a 724cc B&S vertical shaft 25 hp engine on my lawn tractor/mower. (It is the little brother of the nicer Vanguard 810cc engine that Tipi is modifying for flight use). It has been a remarkably trouble free engine for the approx 5 years Ive owned it, and I don't fuss over it much. I run...
  5. V

    Inherent, quiet?

    As I mentioned, acoustics weren't the primary driver for the geometry, but the design does help. The B-2 is loud at high power settings (on takeoff, etc). In a flyby at more moderate power settings, the plane is relatively quiet from underneath (for a 300,000 lb airplane). Yeah, louder if...
  6. V

    Harbor Freight Predator 670 V-Twin Horsepower tests

    Gregory, On your mini bike, did you keep the stock fan/blower on the engine?
  7. V

    Harbor Freight Predator 670 V-Twin Horsepower tests

    I can't find the info now, but I recall one of the Rheinbeck aerodrome guys rigged up a cordless drill or impact wrench to start the VW on his WWI replica from inside the plane. Sounded pretty neat. Long shaft, universal joint and I don't remember if it was a sprag clutch or some kind of...
  8. V

    Inherent, quiet?

    I believe acoustic signature reduction was one reason (not the main one) for the design of the B-2 engine exhaust geometry.
  9. V

    Harbor Freight Predator 670 V-Twin Horsepower tests

    This is a head scratcher. Thermocouples, welding crayons, or an IR non-contact thermometer aimed at the head near the exhaust port will help you keep an eye on it. This is quite a project. Even if the direct drive prop doesn't produce enough thrust for the Ultracruiser, something like this...
  10. V

    Inherent, quiet?

    All my planes got quieter when the instructor got out. For quiet, build a one seater.
  11. V

    Harbor Freight Predator 670 V-Twin Horsepower tests

    It looks like he's already matched the 26 HP of a Rotax 277, and 3900 RPM with a 46” prop won't present any problems with tip speeds. The challenges might be: - Prop efficiency of a relatively short prop at t the Ultracruiser airspeed - Engine cooling at high output, Ultracruiser speeds, no...
  12. V

    Formula-I?

    If mounting the prop on the flywheel side (stubby tapered end) would you suggest just requiring the same 1 1/8" minimum crankshaft diameter at the bearing and the same max 6" max distance from the outer bearing shoulder to the prop flange surface? Thus, if the flywheel is present its thickness...
  13. V

    Formula-I?

    Thanks for re-looking at this. I know some people concentrate on the relative adequacy of the flywheel bearing vs the PTO bearing, and that's certainly worth examining. But, compared to a bearing failure, a crank fracture outside of the case potentially provides a lot less warning and a more...
  14. V

    Formula-I?

    As far as I know, closest thing that is generally available today is the IVOprop electric in flight adjustable prop. The "ultralight" version is good for up to 100 HP, blades are available for diameters of 48-"72", and pitch can be run from 18"-52" or 35” - 72". It sells for $1400 (2 blade...
  15. V

    Boeing - Design Issues...

    Ahh, the dreaded "CND' (" Could Not Duplicate") in the aircraft maintenance forms. Not a big deal if the prior write up was minor, but legitimate cause for concern with "smoke in cockpit" etc. "Hey, can we maybe give this one an extra hour of effort by the varsity team?"
  16. V

    DA11?

    I believe it is likely well behaved. But it is more plane (with more power) than a DA-11. New pilots drop planes in occasionally, so really sturdy gear (and everything indirectly attached to it) is a great virtue in a trainer. Their scan is slower and they haven't seen enough to have a...
  17. V

    DA11?

    Sorry, but I just can't imagine that a DA-11 or anything resembling it could be thought of as a trainer for a new pilot--a good airplane in which to reach basic proficiency in the skills of piloting a plane.
  18. V

    Hummel engines vs Team minimax engines

    I'm not sure what their relationship is. One interesting tidbit: In this writeup on Scott Casler's offerings in Ultralight Aircraft Magazine, there's this: "Hummel Engines have powered aircraft designs like the Sonerai, Sonex, Ultracruiser Plus, Aerosport Quail, Avid Flyer, Corby Starlet and...
  19. V

    DA11?

    Roomy, too. Well, enough to attend to attend to "plumbing requirements" of such a trip. A DA-11? A little trickier. Would it work? Depends.©
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