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. Apr 8, 2019 #461

    Dillpickle

    Dillpickle

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    Hey Pops, I'm assuming--yes, dangerous, I know--that the armrests are as much for MENTAL comfort and security as anything else. I was thinking a real light cable suspended, aluminum tube "U" shape mounted just behind the seat. It could rotatate up, out of the way while you mount, then rotate down, stopped by a cable. I flew a buddy's S18, and, man it was disconcerting being strapped to what appeared to be nothing. I don't think I'd get the same "too exposed" feeling from the Ranger though. I flew another airplane called a Ranger, one designed by The EMG designer, and it was kind of straddled and had leg fairings. It felt fine with no armrests, and was a HOOT to fly.
     
  2. Apr 8, 2019 #462

    BJC

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    There is nothing wrong with providing input to a designer, but implying that another designer has not thought about his decisions is inappropriate.

    Please start a thread, post drawings and information on your design, and share your decision making, which, I’m certain, has had lots of thought to make it light and strong.


    BJC
     
    Dillpickle and FritzW like this.
  3. Apr 8, 2019 #463

    rtfm

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    Why do you think the geodetic superior to the plywood design first suggested? Looks like a an awful lot of work to me. I far prefer the simplicity of the cnc cut plywood (with doublers, of course.) I can't see how cutting a zillion sticks and then accurately attaching them is preferable...
     
  4. Apr 8, 2019 #464

    rotax618

    rotax618

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    I have suggested the type of construction which is lighter and simpler - the type of tail group was to use the Team, or Fisher or dozens of other very light aircraft use rather than a much heavier and more unique system used almost exclusively on the VP, which incidentally is a very much heavier class of ultralight.
    All I say is just do the homework and compare the strength/weight ratio of the two types of construction, it is obvious to me which one is lighter.
     
  5. Apr 8, 2019 #465

    rotax618

    rotax618

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    By the way I have know a bit about the VP structure, I built one nearly 50 years ago.
     
  6. Apr 8, 2019 #466

    Pops

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    I have built several geodetic Fisher type wings. Each wing panel on the SSSC weighs 37 lbs. That is hard to beat. Not a lot of work, the strips are at about a 45 deg angle and go from the front spar to the rear spar, no little short pieces but long pieces. Once a wing is blocked in position with the ribs glued to the spars, glue a set of strip in one direction. Takes about 2 hrs. Next day do the other direction,( use spring type cloths pins where they cross) . Next day flip wing and do the other side. No more work than installing drag and anti-drag wires.
    I don't consider the fun of building an airplane work.
     
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  7. Apr 8, 2019 #467

    erkki67

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    Fritz, how much suspension travel at the shock absorber is required?
     
  8. Apr 8, 2019 #468

    D_limiter

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    Just want to say that it has been an education and a privilege to watch the design process on this cool project unfold. I’ve been looking for an easy to build, folding wing plane to build with my son, and the ranger concept looks very inticing.

    My son is taking flying lessons, so for our purposes, we wouldn’t need part 103. But I know what my 2 cents are worth ;-)

    Fritz, thanks for all of your efforts!
     
  9. Apr 8, 2019 #469

    FritzW

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    Re: the rudder and stab
    In typical internet fashion, Rotax618 is making incorrect assumptions and only looking at narrow set of conditions to justify an apples and oranges comparison to address his personal pet peeves.

    Incorrect assumptions
    1) Full flying tails are heavier than conventional tails.
    ...apples and oranges comparison: VP rudders are heavier than MiniMax rudders and that proves that the completely different Ranger rudder is too heavy.
    2) Full flying tails are harder to build than conventional tails.
    ...Unjustified BS. The 'ol "throw in a quick, false, 'fact' and hope no one catches you" trick.
    3) The MiniMax tail is lighter than the Ranger tail.
    ...How much does a MiniMax fin and rudder weigh? You don't know. How much does a Ranger rudder weigh? You don't know. But you do know that the Ranger rudder is heavier???
    4) The MiniMax tail is easier to build the the Ranger tail.
    ...More unjustified BS. Have you ever built a MiniMax rudder? I have, carving the laminated LE is pretty time consuming and tedious. Have you ever built a Ranger rudder? Of course not. So how do you know it's harder to build? The whole reason I went with the idea is because it's light, simple, rugged and easy to make with a CNC machine.
    5) Evans was a poor designer because the VP tails are heavier than they need be.
    ...Evan's design goal was to make a rudder that was cheap and easy to build in a 1968 garage with typical 1968 garage tools and 1968 materials and would be aerodynamically sound and structurally safe. He succeeded in spades. People are still building his design 50 years later I've built two VP's and have more than 1000 VP hours. I can say for a fact he got it right.
    5a) By association I'm a poor designer because I'm using a VP tail on the Ranger.
    ...I'm not using a VP rudder on the Ranger, I'm using a Ranger rudder on the Ranger. It's a VP rudder designed to be cheap and easy to build in a typical 2021 garage with typical 2021 tools and materials.

    You know nothing about the Ranger rudder and stab other than the fact that it looks like a VP rudder and stab. You haven't made a single valid argument against VP style Ranger tail feathers.
     
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  10. Apr 8, 2019 #470

    FritzW

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    I got seduced by the idea of running a $4 Lowes 1x4 through the table saw a dozen times and having the basic rear fuselage kit. It's not as easy as pushing a button on the CNC machine but almost.

    I also think it's not going to be that much different (in time and fiddlyness) than the splices and doublers of the all ply tail cone.

    And it may just be mental but the geo seems like it will be more rugged, durable and repairable for landing out in the sticks. ...which is the main purpose (for me) of the Ranger.

    And finally: I'm only 25% done with the design and I'm already starting to show symptoms of advanced CAD Maddness. ...and I want to start building this thing tonight.
     
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  11. Apr 8, 2019 #471

    pictsidhe

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    Fritz, try not to let the naysayers who aren't running your numbers and building your plane get under your skin. Yeah yeah, I know that's easier said than done...
    Geodetic is famously rugged. If the numbers and the construction works, go for it. Perhaps after learning how pops builds them...
    I've found the larger sizes of construction lumber to be the best quality. But, the bigger ones are often SYP instead of red/white spruce. Lowes tends to have better wood than HD in my area.
    Tulip polar is available in my local big boxes, it looks like a decent wood to use, though a little brittle. But, with a geodetic, that's less of an issue.
     
  12. Apr 8, 2019 #472

    erkki67

    erkki67

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    It seams to me that several kit manufacturers used the geodetic construction methods with success.

    Hey Rotax618, the Jodel line or some of them uses monoblock rudders and elevators, the Luciole of Colomban uses all flying elevator and a strange looking fin with huge success, those engineers are or were no idiots.
    Fritz is using a similar style combined with modern manufacturing methods, what is wrong with it?
    You don’t like the design, no problem, just jump off this thread and leave it as it goes.
    For what ever reason you are shooting with canons, leave it.
     
  13. Apr 8, 2019 #473

    Dillpickle

    Dillpickle

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    Once Upon A Time, a long, long time ago, I taught Language and Logic to High School students. It was eye opening. Most students can parrot what they feel so very strongly is the truth, but can not defend it logically. I have a hard time "suffer(ing) fools gladly." You patiently take the time to correct misconception, without the addition of vitriol--uncommon in the anonymity of the internet. It is a pleasure to read your posts.
     
  14. Apr 8, 2019 #474

    Little Scrapper

    Little Scrapper

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    I'm having a hard time understanding this airplane. But guess what, it doesn't matter. I can't quite see your vision but I can surely appreciate your work.

    Fritz, what you're doing is absolutely bad azz. Please don't stop, plow through this process and fly it because that in itself makes you a man among men.

    Looking forward to seeing this unfold.

    Mike
     
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  15. Apr 9, 2019 #475

    103

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    My Cygnet SF2A has a Geodetic wing. It is very torsional stiff and rugged.

    REF:
    https://www.google.com/search?q=geo...l8LhAhVJA6wKHSJfAsEQ_AUIDigB&biw=1160&bih=589
    Many Wembly's flew home with large sections of the fuselage missing

    http://www.1940.co.uk/acatalog/Barnes-Wallis.html

    I like Geodetic. The "fiddly" bits are simple rectangle cross section epoxied to the longerons and each other at the intersections.
     
  16. Apr 9, 2019 #476

    103

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    See post #475
     
  17. Apr 9, 2019 #477

    Geraldc

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  18. Apr 9, 2019 #478

    FritzW

    FritzW

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    The dust was flying tonight!

    20190408_212610_resized.png I'm committed to the geodetic tail cone now, I dug into my good wood stash. ...and that stuff doesn't grow on trees.

    20190408_212636_resized.png I went with the big instruments stacked in the middle. I wasn't going to but I was worried about having enough hand room to get the nuts and washers on the gear strut bolts, they're right next to the upper instrument (steam gauge ASI, I don't like electronical instruments)

    20190408_212627_resized.png The cleco idea is going to work great. I only used it on the splice, I wish I had used it for the whole fuselage

    Ranger 2G Sheet 1.png I was able to get almost half the fuselage on one sheet. I've only got one more sheet of 1/8" so I'm going to have to order some more. The G code and DXF's are on the groups.io group.
     
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  19. Apr 9, 2019 #479

    rtfm

    rtfm

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    Way to go with building, Fritz! Looking great. So, fuse from three sheets. How much wood for the geo tail? I'll probably use Hoop Pine (in the absence of decent wood from the hardware store) Just need to know dimensions and quantity. What are you going to cover it with?
     
  20. Apr 9, 2019 #480

    rtfm

    rtfm

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    I've been thinking about wings. Yes, I know that I have a set of Aeromax/MiniMax wings. Not covered, but built. However, while I wait for my CNC router to arrive, I've been thinking about Fritz' rib-o-matic tool, and thinking about how the SD-1 and Flying Fleas build wings. And here's where my thoughts led me (while sitting in the bus for an hour this morning.)
    1. Cut the ribs
      Use my flash new CNC router armed with an "electric needle" - a heated needle mounted on the router plate - to cut the 1" foam ribs
    2. Mount them in/on the rib-o-matic
    3. Bond the front and rear spars (20mm x 20mm Hoop Pine (similar to Spruce), with 1mm ply shear web.
      Actually, these aren't "spars" in the usual sense of the word, in that they are not there primarily to bear any loads (they will, of course) but to close off both ends of the ribs, and to provide a surface onto which to bond the wing surfaces.
    4. The surfaces are 1mm plywood (SD-1 style). Each 2400 x 1200 piece of 1mm plywood weighs 2.3kg. That's a total weight (including epoxy) of under 14kg
    5. Bond carbon fibre rods directly to the plywood along the thickest part of the wing. This will be the spar cap.
    So what one ends up with is a wing with the main spar at the thickest part of the wing, two light-weight closing-off spars front and back, and ribs made entirely of foam (the wing surface bonds directly to the foam, so no need for strips to be bonded to each rib). The wing should be incredibly stiff, and by correctly calculating the number of CF rods, one could build it to any G rating.

    Borrowing from the Flying Flea - I'd build the wing in three sections. A central section of 2400mm, and two outer panels on hinges of 1800mm each, resulting in a wing of 6m (just over 19ft 8in) Add on two wing tips, and we have a 24ft wing.
     

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