Folding-wing biplane?

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IanJ

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I've been pondering building a plane for a year or two now, and actually gave up on it half a year ago due to the huge ongoing costs of hangaring, insurance, etc. With the return of decent flying weather, I gave the idea another shot, and ran across the Sherwood Ranger, which is a wood and metal, fabric-covered biplane kit from England. The key thing that revived my interest, though, is the fact that it's designed with folding wings in mind. Not the "30 minutes' setup" folding wings, either, but actual "pull this pin and fold" type folding, without having to rerig or detach controls, etc. The Sherwood Ranger suffers from the fact that, as far as I can tell, only one has been built in the US.

There's also the all-metal FK12 Comet, which is less interesting to me, from the standpoint that I'd like to build a wooden (or mostly wooden, anyway) airplane. It's got quick-folding wings, but it's pricey and higher performance than I want. All of my flying these days is the "around the patch" type, with maybe the odd cross-country thrown in every year or two.

The folding-wing idea appeals to me largely because I can skip the $400+/mo hangar fee (assuming I could even get a hangar), and the fast folding setup means I would actually fly the thing instead of getting that mental-inertia stop of knowing I'd have to do all that setup. If I can easily load and unload the plane from a trailer, then it can live in a garage or outbuilding.

I've also run across the Fly Baby (which can be built as a bipe), but it's got a comparatively lengthy setup time, and is only available as a one-seater. The Fly Baby does appeal to me, though: being in Seattle as I am, there's a ton of FB knowledge available in the area.

I'm interested in a lightweight plane, as light as is practical to contain two human-sized people (ie, 400 lbs of person) and gas in the thing without busting the max load. Ideally, it'd have enough avionics on board to be able to fly in the Mode C veil (xponder, one COM, encoding alt or blind encoder, plus the normal VFR instruments). I'm not about to set myself up with a hand-prop engine if I can avoid it, so I can't sneak by with the "no electrical system" loophole.

So, what else is out there? Are there other planes that are lightweight, and really easily fold up? Am I courting disaster with a folding-wing setup? I'd love to have input from other homebuilders.
 

Dana

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All of the Kolb aircraft have easy (10 minutes) folding wings, though none are biplanes. Single or two seat, ultralight or LSA.

-Dana

The citizens of the United States are getting the government they deserve. The problem is that I'm also getting the government they deserve.
 

Raptor

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Nov 23, 2006
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San Mateo, CA
Ragwing makes a 2-place, tube/fabric/wood 'Pitts' replica (RW26), here's a website with info: www.ragwing.net/articles/RagWingMann_nov96.html

I've had experience towing a friends Soneri around a lot, and I wouldn't recomend road travel, without a trailer, preferably enclosed. The poor thing got BEAT with rock strikes and the same kind of damage you'd get in a parking lot. I was even backed into, in a gas station.

My choice would be to find a hanger you can share, my neighbor shares with a Kitfox, and that seems to work pretty well.

Good Luck,
Paul
 
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orion

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Although the folding wing option is a common discussion and/or request, the number of kit or plan developers who offer this capability are relatively few. The main reason is simply because it does take quite abit of extra work to design, engineer and prototype the mechanism(s) (read: added cost to design and implement) and in the long run the number of people who actually use it is very small. Depite the best of intentions, most people eventually find a spot on the airport and never fold the wings again.

In your case you might want to check out Harvey Field (Snohomish Co. Airport) - if available the hangars go for substantially less than $400/mo (especially the older ones) and you also have a second option, that being the outside covered parking, which is cheaper yet.
 

IanJ

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I've thought about Harvey Field, since that's where I'd probably want to fly from anyway. It just doesn't feel right to fly a small biplane out of an asphalt strip. :D

I do recall looking for info on Harvey's hangers, and came away with the impression that they were about as pricey as anywhere else (read: hundreds of dollars per month). I'll check again, and see what I can see. [edit] Harvey has open hangars for $105 and 155 (small and standard, whatever that means) and enclosed hangars for $250-400/mo.

At this point, I haven't bought a kit, and have nowhere to build until after I find my next house. I have some time to figure it out. However, my choice of what to build will be strongly influenced by ongoing costs, including hangar space.
 
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orion

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Just FYI, Harvey has a grass strip paralleling the main runway to the West. Quite a few bipes out there already.

The small and standard are just dimensional terms reflecting the size of airplane you could get in. Most of the older covered spaces are probably the smaller of the two possibilities - the newer construction allows for larger aircraft including twins.

I think Harvey also has outside tie-down spaces although don't quote me on that.
 

IanJ

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Just FYI, Harvey has a grass strip paralleling the main runway to the West. Quite a few bipes out there already.
Yep, that's why it would be my first choice. I should head out there some sunny Saturday and see if I can corner any biplane pilots.

The small and standard are just dimensional terms reflecting the size of airplane you could get in. Most of the older covered spaces are probably the smaller of the two possibilities - the newer construction allows for larger aircraft including twins.
That's what I figured. That question will also be answered if I go visit on some sunny Saturday.

I think Harvey also has outside tie-down spaces although don't quote me on that.
Indeed they do, and they're cheap, but uncovered storage seems like a poor choice for a ragwing wooden biplane. I even question whether an unenclosed covered parking spot is advisable vs. an enclosed hangar. I guess it depends a lot on whether the open end is north-facing or south-facing.
 

base363

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I too started a project with one of the primary considerations being the ability to fold the wings.

http://www.blackhillsairsports.com/STOL_King_Intro2.html

Since I started, and really thought about the practicality of the design, I opted to abandon the folding wing, and attach the wings in the conventional manner.

I can hardly find time for someone else to change the oil in my car, let alone fold the wings on an airplane and trailer it around!

Colin

http://www.jumprunenterprises.com
 

IanJ

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I've read a lot of your site before, very interesting stuff, Colin. Did you decide that the cost of hangarage was worth more than the hassle of folding/trailering? I can easily foresee myself getting frustrated with monthly costs well before I get frustrated with hooking a trailer up to a truck on the way to the airport (I have to drive there anyway...).

Thanks for your input.
 

base363

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There are several reasons, but the biggest one is practicality.

1. Folding the wings on most aircraft is a time consuming and involved task. Usually involves disconnecting flight controls, fuel lines, wiring or cannon plugs.

2. It probably takes a couple people to do it. So it eliminates the convenience of those spur of the moment evening flights.

3. Increases the probability of damage to the aircraft, both during the folding procedure and loading.

4. Greatly increases the complexity of building the airplane. And anytime you have a moving part, it gives you one more thing to go wrong. So to me, safety is an issue.

5. If I really need to move the airplane or trailer it, I still have the option of simply removing the wings.

For me, as with most things in life, it comes down to how bad you want it?

I will find a way to hangar the airplane and pay the expense. I just look at it as a part of the cost of aircraft ownership.

I’m currently leasing a hangar for $225 month for a Cessna 182 I use for skydiving. Allot of money, but I find a way to pay the bill.

Colin

http://www.jumprunenterprises.com
 

IanJ

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What's interesting about the Sherwood Ranger is that (they claim) the folding process only takes a few minutes, and doesn't involve detaching any controls or unrigging anything. I've yet to see one of these things in person, so I take that claim with a huge grain of salt, but if it's true, that's very intriguing.

Quoth their sales copy: "The “ Sherwood Ranger” is a lightweight two seat open cockpit biplane, designed to reduce the cost of owning and operating your own aeroplane to the absolute minimum. One of its major features is that the wings can be folded and the aeroplane loaded onto a trailer in less than three minutes, thus eliminating hangarage costs by allowing the aeroplane to be stored at home."

Given that the folding wing was a central design consideration (the designer was trying to go for the simplest, cheapest way to fly, which aligns very well with my own desires), it strikes me that it was likely done right. There are a number of flying examples in Britain, but I've only found one registered in the US.

Hopefully I'll be able to see one in person at Arlington in July, or at least talk to someone who's seen a completed plane.

Of course, what argues strongly against the Ranger is the apparent lack of information. There's practically nothing out there about the plane. Even the Biplane Forum appears to have entirely glossed over its existence. In this age of vociferous advocacy via the 'net, it's something of a damning situation when no one's talking about a model.
 
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PTAirco

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Regarding the Sherwood Ranger:

I saw this design about a decade ago in England and talked with the designer a little. It does fold like it says. In the late 20's/30's in England the majority of common aeroplanes had some folding feature and none required the de-connecting of controls. Generally you pulled a handle in the leading edge, close to the wingroots, wich withdrew the main spar pins, and simply swung back the wings. Sometimes you had to first unfold a jury strut to hold the upper and lower wings in alignment. I still think it is a useful feature if it is kept convenient and easy to do, wether you have a hangar or not.

The Ranger is a nice flying aeroplane, very light, as it it was originally designed to then current microlight regs (880lbs max take-off weight and 5 psf wing loading - not an easy thing to make a two seater aeroplane with). Construction looks easy too if you trust glassed-on ply wood ribs to a aluminium tube spar.
 

IanJ

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Thank you, PTAirco, you're the first person I've run across who's actually seen one in person! I'm glad to hear the folding mechanism works as advertised, that is very encouraging.

On the glassed-on ply ribs, that seems like a better method than riveting or doing anything else which would put holes in the spar. If the rib encounters any twisting-about or sliding-along the spar forces, you're in far worse trouble than worrying about whether that fiberglass is going to hold.

I am amazed at the weight, actually. I almost can't believe it's true, and would certainly have to watch out for making heavy mods: I'm a heavy guy, and all my "engineering" up to this point has been of the "make it so stout there's no question it's strong enough" type. I also wonder whether it's the right design if I want to add in an electrical system (I really want to be able to fly in the Mode C veil, and at night, and I'd rather avoid hand-propping if at all possible) -- mostly from a weight standpoint.

In any case, I appreciate your feedback. It's very helpful to get independent confirmation on some of the less immediately believable claims.
 

plncraze

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Did anyone order the plans? What was the quality and the cost? According to the website the plans are 195 pounds which works out to approx $384 plus shipping. It is a good looking airplane. I am a large person too (6'4" 240 lbs.) and I was wondering if I would fit.
 

bmcj

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The main reason is simply because it does take quite abit of extra work to design, engineer and prototype the mechanism(s)
Though not as compact for towing or storing, I would think that you could create a lightweight biplane which simply allowed pulling 5 pins on each side (upper/lower fore/aft spar pins plus aileron linkage pin). The wings could then be removed fully braced and intact (picture two box kites - one on each side of the plane), leaving the fuselage and center section(s). This would require some additional engineering and reinforcements due to the fact that all flying and landing wires now tie into the detached portion of the spars rather than the fuselage. The two "box kite" sections could then be partially nested together to save on space.

Note: be careful on windy days!

Bruce
 

IanJ

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For myself, there would also be lighting wires (quick-disconnect connectors aren't hard to deal with, though) and pitot air (again, not a show-stopper, but another complication).

What I really like about the Ranger design is that nothing has to be disconnected.

For what it's worth, it does appear that the Ranger is unavailable. I found a message board on the TLAC site, and the last real (non-spam) post there is from December 2006, about how the company is unexpectedly out of business or no longer owned by the same person or something. So it may all be a moot point anyway. ;)
 

paulgy80

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Little Snoring, Norfolk
Dear All

Nice to see a link on the Sherwood Ranger, and yes it is back in production and for somebody who said they were 6'4" would they fit, well one of my employee's is the same height and fly's a Pitts S1, he recently got into the Sherwood and said he felt comfotable.

We took over the Sherwood project just over a year ago now and there has been a lot of sorting out to do and there is a little way to go yet. We are taking orders for the aircraft at this time and we have the first kit under production for Malta ( a little island off the bottom of Italy). I can confirm that the wings fold and do so very easily, just a one person job and from the trailer to pre flight 3 to 5 minutes. No cables to mess around with and no tubes or hoses, just 4 pins to pull.

We are currently looking for dealers in the US so if anybody is interested or knows somebody who might fit the bill then please feel free to give me a shout. Our new website is www.g-tlac.com and my e mail is paul(at)g-tlac.com.

Oh forgot to mention, she is available in both microlight and Cat A, both 450kg MTOW that is about 990 lbs, the ST has 26 foot span and we have the clip wing version, the XP with approx 22 foot span, the Jabi engine at 85hp works really well as does the Rotax 582.

Regards

Paul
 
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