# 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. Feb 23, 2019

### bifft

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I've been thinking a lot about a folding high wing lately. My idea is Grumman Sto-wing inspired. Fold the wing down and back. Lock in place with a single pin at the rear spar. Should be easy to do alone.

Have the horizontal stab be far enough back that it doesn't have to come off and short span enough that you can trailer it with the stab attached (leads to low aspect ratio).

Have the full span flaperons driven by pulleys lined up with the fold axis like this (http://1.bp.blogspot.com/-5XWjXMsPe...OweWs/s1600/TBF+Aileron+Control+Pulleys+2.jpg) so they never need to be disconnected and can't be reconnected wrong.

The strut also stays connected. Have the lower and upper strut rotation axis meet at a 90 degree angle on a point that is on the main fold axis. This does mean that the strut bottom and wing fold need to be set out from the fuselage enough to let the wing fold down.

I'm not good at drawing pictures, so am planning on making a small scale model to test the fold geometry. Not sure when I'll get around to that. Here is the napkin sketch I have been using so far:

Problems I haven't figured out yet: It looks to me like the structure will be statically indeterminate with the strut in place, but not so if done as a cantilever. It should be conservative to calculate the loads on the rear spar/locking pin as if the strut wasn't there, and the strut as if the rear pin was taking only the torsion/drag-antidrag loads. However, would this then end up being heavier than just making it cantilever in the first place? I've only read a little on structures so would need to study more before I could answer this one.

Don't want to hijack this great thread, so if anybody wants to discuss this napkin sketch in more detail let me know and I can start a new thread.

2. Feb 23, 2019

### FritzW

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I didn't draw those models today, they're actually pretty old. But they did go together pretty fast (4 or 5 hours for the whole fuselage model). The trick is to make sure your "mental concept" is something that would be easy to build. If it's something that would be quick and easy to build in real life, it'll be quick and easy to build (draw) on the computer.

VB
It's all stock sheet and extrusions available from Aircraft Spruce. All CNC cut and drilled and no bending. Some of the extrusions had to be beefy where things like the motor and gear mount but could be much lighter a few inches away. Since it's going to be cut on a CNC machine it's easier and lighter to just cut away the dead weight than it would be to splice in a lighter material where the loads are much less (I hope that made sense).

If your working with a hacksaw and drillpress it would be "labor intensive and complex" but with *CNC it's actually an easier, simpler and lighter way to do it.

*if you had templates and a good hand router it'd be almost as easy as doing it with a CNC machine.

3. Feb 23, 2019

### erkki67

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The wooden one please, skylight wings would be ok.

4. Feb 24, 2019

### Pops

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I have a wide bottom, how wide is the seat ? and do I have to have my legs outside in the breeze ? 1/2 VW ?

5. Feb 24, 2019

### FritzW

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I'd just snag the seat off a cheap fiberglass or plastic lunchroom chair from Costco. ...or sneak a screwdriver into the food court at the local mall. The seat would mount to two blocks/rails glued to the top of the longerons.

A two piece seat would work just as well.

A seat like this would add moral support if the ball wasn't centered.

Legs are on the outside. ...but fairings were talked about (and sketched) on the original thread.

A 1/2 VW would be great. It would take a little reworking for the mounting.

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6. Feb 24, 2019

### Pops

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I like the seat idea. What is a mall?, remember we don't have a stop light in this county
Fairing would be nice, hate to have a bumble bee or hornet go up my pants leg just after takeoff.

7. Feb 24, 2019

### Tiger Tim

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8. Feb 24, 2019

### FritzW

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...$30 !?!?!?!? :shock: ...I'll use the$0.99 kind (I had handfuls of them but the cats steal them and hide them under the washing machine)

9. Feb 24, 2019

### Tiger Tim

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Really when I’m out on one of my bicycles I just let my cuffs get all greasy and tangled. I thought thirty bucks looked expensive too but had nothing to reference that against.

I’d be the guy flying a Ranger in shorts year round anyways...

10. Feb 25, 2019

### EzyBuildWing

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11. Feb 25, 2019

### Aerowerx

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Yes, but everyone can mix epoxy in a cup. Not everyone has a welding machine, or knows how to use it.

12. Feb 25, 2019

### Victor Bravo

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Regarding a welded fuselage for the Ranger, the welded furselage Air-Bike and Legal Eagle already exist, and we have more or less narrowed down this particular discussion to sheet wood and sheet metal for the Ranger.

I cannot speak for everyone else but I believe I'm on reasonably solid ground in saying that a large number of people are very interested in this Ranger version, made out of sheet materials that can be cut out on a panel router or waterjet machine.

I'm sorry to be heavy-handed without any official authority, but I do believe that this design justifies a dedicated thread that stays within a narrow range of configurations and materials. HBA is overflowing with hundreds of other equally valid and interesting discussions for everything from corroplast sign material to foam and glass to steel tube to filament wound dental floss.

Last edited: Feb 25, 2019
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13. Feb 25, 2019

### FritzW

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I sent the model and a drawing to Erkki a few days ago. I think he's going to build a mock up out of junk ply to see if he fits as well as my 6'2" CAD pilot. ...I hope his feet don't stick into the prop :shock:

Hopefully I'll get a chance to put the new wing (a new take on tube spars and foam) and the tail feathers on it tomorrow. Tuesday mornings are my only 'day off' since I retired :gig:

14. Feb 25, 2019

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Fritz,

Would it be possible to have a look at the solidworks files for the metal version? I could see if the Skylite wings fit or possible use it as a seed model to make them fit. If your open to it what version are you using. I use SW2017 and if your using newer than a Step or parasolid file would be best.

Marc

15. Feb 26, 2019

### Topaz

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Just make sure the seat-pan you use can support, in its designed mounts, your body weight at the ultimate design g-loading. It's why Orion used to always admonish against sling-seats: It's a bad day when your airplane structure stays together, but the seat fails and you either fall through the fuselage bottom or get yanked away from the controls. Same goes with crashworthiness.

IMHO, of the ones shown, I'd be inclined to use the two-piece example, and to do a load-test check that the plastic mounts in the seat pan don't crush through under an ultimate-loading, maximum weight pilot scenario.

16. Feb 26, 2019

### FritzW

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Sure, I'm still using '15 so it'll load on your system no problem. PM sent

17. Feb 26, 2019

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Fritz,

Thank you for the Ranger files in Metal. I received them and all is good. I already have the engine from another project so wont need that. Anyhow, I just opened it and decided to do an overlay of the Skylite tubular fuselage assembly and **** if they aren't close. I mated the firewall on the same plane than raised the fuselage up until the seat floorboard support matched your metal floorboard location. When i did that I could see that the landing gear on both are in the same position and to adapt the larger chord wing of the skylite (or maybe you have same chord but inboard connection points) the difference is nearly evenly spit fore and aft. My mating the firewalls is not all that realistic as with the motor mount the Skylite firewall should be a bit behind the Ranger. Yet its all quite similar. However the skylite is part 103 and the ranger with the larger briggs might end up heavier overall but likely close enough that the moments will be similar. So this verifies that I could pretty much build a thinner skylite and come out OK. Or take this and run with it a bit if your open to that. I do like the look of the wood Ranger better with the sleek boom.

My only observation of concern is the rudder pedals on the skylite are nearly all the way up against the firewall so on the Ranger they may need to be just as far forward since the seat geometry is nearly the same. However on the Skylite the feet are up higher and the lower pedal location on the ranger would bring them in a bit. Just extending the nose 6" or so would give more space between feet and firewall/engine mount location. I know being 6'4" tall I would not want to have any chance to chop my feet in the prop should I stretch the legs out in flight.

Anyhow pics below for comparison.

Marc

18. Feb 26, 2019

### FritzW

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Actually the seat/mounts need to be designed for a much higher load than the pilots weight at ultimate g-load. That would only keep the seat/mounts from failing in flight. A bad landing would be much higher than that.

Just for a mental picture: compare the main spar and main spar strut attach point of wings like the MiniMax or Legal Eagle with the structure where the (yet to be drawn) seat mounts go on the Ranger. It's like mounting the seat on two main spars at the strut attach points and running a 4" aluminum between them.

The Ranger is like the VP, you could fly it without a seat. It'd be like sitting on a milk stool but it wouldn't make any difference structurally.

>>>Sorry VB but I'm going to drift a little OT. The gauntlet has been thrown down and the honor of the Neirrh is at stake :gig:<<<

I adamantly disagree. There's nothing wrong with sling seats. There's no reason that a properly designed sling seat would fail any differently than any other type of properly designed seat. And there are no possible forces that could "yank you away from the controls" any differently than any other type of seat. ...not counting the suicide seat rails on pre-AD Cessna's

...sling seats aren't like play ground swings or the hammocks on Gilligan's Island. With the seat belt and shoulder harness on there's virtually no free movement in the seat.

I know you didn't mention the Neirrh seat specifically but, as for strength: The weakest link on this seat is probably the grommets. They were tested to 250 lbs but they're probably worth at least twice that. But using 250 lbs makes the seat good for 20 g on a 250 lb pilot. When you start adding in the reality factors (ie. the weight of the pilots legs doesn't count against the load on this type of seat etc.) the seat is obviously good for more than the fuselage it's mounted in.

Sorry for the long winded rant but sling seats are light weight, strong, safe, affordable, easy to make and hard to screw up. To say you'll fall out the bottom of the airplane, get yanked away from the controls or they're not crash-worthy is just urban myth.

Last edited: Feb 26, 2019
19. Feb 26, 2019

### FritzW

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Marc,

Do whatever you want with the files, if you get rich and famous designing an airplane from them I hope you'll send me a copy of the plans

You could cut the tail cone off and use a boom. The wood Ranger (with the boom) started out as the wood version of the one I sent you, I just took the rear fuselage off and put a Hovey style boom mount on the rear of the wing pylon and new bulkheads all the way up to the instrument panel.

The wing I drew for the one I sent you (the aluminum CE) is the fabric covered, aluminum, truss rib, pop rivet one that I've posted on here a couple of times. I think the cord is ~50" and the spars are ~28" apart so the location of the Skylite's LE and TE tube spars makes sense on the pictures you posted.

I think in real life it'd be hard to get your feet in the prop. The prop is going to be several inches past the front of the motor mount 'lip'. But it's something that definitely needs to be checked. Hopefully Erkki will make a mock up and check. ...if he can't get his feet in the prop, no one can :gig:

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20. Feb 26, 2019

### Victor Bravo

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Fritz, by any chance did you ask Solidworks whether the sheet metal tailcone was lighter or heavier than the aluminum tube tailboom? I'd be curious whether one was heavier. I can imagine the round boom is a little less wetted area and therefore a little less drag, but that might come at the penalty of a few pounds' worth of metal. I'm pretty sure the round boom will need a slightly larger fin/rudder to achieve the same tail volume as the slab sided one.

Fritz and/or Marc, I do have a humble request. What would the sheet metal version of the Ranger look like if (instead of the Skylite wing or the Columbus Explorer wing) you grafted a 12% smaller version of the Zenith CH-701 wing onto it? The advantages of the Zenith style wing are very much in line with the intent and mission of the Ranger... easily built, parts easily cut on a router, laser, or waterjet, ability to be left unpainted, and very much a "rough and tumble" wing for a knock-about airplane.

(I'm not talking about the 701's wing slats, leave those out for the purposes of this discussion)

Everything in aviation is a compromise, and of course this idea is too: The Zenith style wing would probably throw the airplane out of any real possibility of meeting Part 103. But that's OK for my personal use, and it may well be OK for many other people's personal use.There aren't many airplanes that can meet Part 103 and are also a "rough and tumble" airplane in the real world. Being able to fly in gusty conditions, off-airport landings on rough ground and pot-holed dirt roads, and living outside in the elements are all part of what I believe the Ranger was all about. (Fritz may disagree and it was his creation).

In the end, the Zenith style wing on the Ranger represents one option out of several different viable options... wood, metal, Part 103, E-AB, round boom versus slab fuselage, etc. etc.

If not obvious already, the direction this is going for me is a sheet metal pop rivet Ranger, with either the round boom or the slab sides, using a Zenith style wing (lightened up a little, but still robust), and either a 993cc V-twin or the Pegasus DP-1 / O-100 for power. Granted this will be outside of Part 103, but for my use and many other people's use that's OK (I need the N number to operate out of my home airport anyway).

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