The Ranger, an easily built high wing LSA runabout

Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by Victor Bravo, Feb 19, 2019.

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  1. Aug 17, 2019 #921

    Jimstix

    Jimstix

    Jimstix

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    Having had some minor experience, it the testing of ACES II seats and Martin-Baker Mk 16 seats for the JSF, perhaps I can shed some light on the realities of ejection seats.

    FYI, the ACES seat is in the A-10, F-15, F-16, F-117, and the B-1B. The MB seat is in the F-35, F-18, and nearly all European jets.

    First, all ejection seats are heavy. For the ACES II, about 250 lbs. ready to rock and the M-B Mk.16, just a few pounds lighter. Both use spigot guns to get the seat moving up the rails, and a rocket motor to provide the remainder of the ride. Both have headbox mounted parachutes and automatic inertia-real tighteners. Both also have leg restraints, but with the ACES seats that is an option.

    The standard maximum pilot weight for the ACES seat is 245 lbs for the pilot + his flight gear. The standard minimum weight for the ACES seat is 104 lbs + her flight gear. Yes, “her” because the only 104 lb USAF pilots I have ever met were female. The M-B Mk.16 has been qualified for the same pilot weight range.

    The acceleration onset rate is different for the two seats with the ACES exhibiting a 250 g/sec jerk (Yep, the third derivative is called “jerk” in the US and jolt by the brits) The M-B Mk.16 seat exhibits about 300 g/sec on the catapult stroke. This is a significant difference and caused many testing iterations to prevent injury to the 104 lb pilot.

    As some of you may be aware, female humans are different from male humans. In ejection seats this is a huge issue. Because female mass moment of inertias, sitting height CG, limb length, most significantly neck length are different than those of their male counterparts, the behavior of the seat on the rails and in flight may be acceptable to the male occupant, while injurious to the small females.

    All of the ACES seat testing that I have witnessed did not “injure” the 104 lb test mannequins that were used. The recorded force and moment data were within acceptable ranges.

    To qualify the M-B Mk.16 for the F-35 took extensive modification and retesting. The end result was that the 104 lb female forces and moments were brought within acceptable ranges.

    Ejecting from any aircraft is exposing the human body to the kinds of forces that can kill the seat occupant unless everything goes right.
     
    litespeed likes this.
  2. Aug 18, 2019 #922

    GeeZee

    GeeZee

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    Please take a look at post 916.
     
  3. Aug 21, 2019 #923

    erkki67

    erkki67

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    I’d like to explore two power plants for the Ranger, one would be an electric engine, a pack from geiger engineering and the second a rebuilt Loncin or Gaokin V Engine.

    For the later I have some more trust, as K. Armstrong has already some experience with the bigger brother of what I would need.
     
  4. Aug 21, 2019 #924

    pictsidhe

    pictsidhe

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    Start with finding out the L/D of a himax, then think really hard about more span... The ranger will be draggier.

    Kevin Armstrong said that he was having a belt wear problem.
     
  5. Aug 22, 2019 #925

    Winchester

    Winchester

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    Will the builder be required to buy Volksplane VP-1 plans from Evans Aircraft in order to build the Rangers' Rudder and Stabilator? Likewise - TEAM Mini-Max for the building of the (Heavily Modified) wings?
     
  6. Aug 24, 2019 #926

    Winchester

    Winchester

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    Any chance of an answer? I have been gathering the posted CNC files in hopes to study the design and eventually build next year. Volksplane plans are $40-$70. The 1700 Hi-Max plans are $100. Using others' IPs negates the Open Source claim for the Ranger, right?
     
  7. Aug 24, 2019 #927

    FritzW

    FritzW

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    I'm guessing you don't know how to send a PM.

    If you go through all 47 pages you'll see that it's not a VP rudder or a MiniMax wing and it doesn't use anyone's IP.
     
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  8. Aug 24, 2019 #928

    Victor Bravo

    Victor Bravo

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    I believe it is safe to say that the only real-world IP involved here is from Fritz. Some of the components may be "inspired by" work done on another aircraft, but I don't think that any of that previous work is the essence of what makes this aircraft different.
     
  9. Aug 24, 2019 #929

    FritzW

    FritzW

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    VB nailed it. The Ranger gets it's DNA from lots of good airplanes: VP's, the Beta Bird, the HiMax, Fishers, etc.
     
  10. Aug 24, 2019 #930

    Winchester

    Winchester

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    FritzW,
    Just slogged through the full thread. It looks like I missed nearly all of early April when the preliminary tail feather details where being posted. (are not finalized yet, which is something I wanted to know)

    My post was addressed in public, to everyone that may be in-the-know. Which I believed to be more than half a dozen Ranger builders and tinkerers. I didn't assume you would answer me (Nobody answered my similar post #811) or that I should address you solely in a PM.

    The wing selection apparently became public with post #692. Which is confusing because it appears to be a halted project, and builders appear to be utilizing ISON derived wings on their own. hence- should I just buy plans.

    I cannot see if the Ranger uses VP tailfeathers because I am not intimately familiar with either yet. Because of the obvious similarities and lack of details- I asked if a builder needed to buy extra sets of plans to complete a Ranger, that's all. I am very satisfied with your response (and VB as well regarding my IP question)
     
  11. Aug 24, 2019 #931

    Victor Bravo

    Victor Bravo

    Victor Bravo

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    If it keeps going like it has been going, there may not even be a set of "construction plans" to look at. The parts will fit together per a bunch of isometric drawings, like a piece of Ikea furniture. If you can cleco the pieces together while the glue sets, the location of the pre-cut holes in the parts would be all you need to build it correctly.
     
    FritzW, Aerowerx and GeeZee like this.
  12. Sep 10, 2019 #932

    rivilee

    rivilee

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    So why are you considering an ejection seat? Wouldn't a parachute be adequate?
    ...oh wait. Never mind...
     

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