Flying wing as cheap and simple option for basic fun flying.

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Hot Wings

Grumpy Cynic
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I am satisfied with my laser/rib flanges that now make tapered wings easy enough for me,.
Have you investigated faster ways of making these - maybe like a rolling punch? Sell it by the roll. Let the builder cut off as much as needed for each rib - or wherever it might be used.
 

Norman

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Just a quick sketch of the various types. ~ to scale. All fuselages = 10 feet.
With a little rearrangement that sketch can be ranked by spar weight. Forward sweep can be very costly in terms of weight because of the extra stiffness needed. Since 'wings require more wing area than tailed airplanes of the same weight to achieve the same landing speed I'm warming up to something like the BOK-5 sans landing flaps. High aspect ratio increases the wing weight and makes it impossible to hide the fuselage in the wing. By having the pilot's torso in the wing you can use the wing for elbow room and storage simply by making rib zero hollow. The blunt nose could be plexiglass to improve visibility with a small bubble to get the pilot's eyes above the wing if you want and a small pod underneath for leg room.
 

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cheapracer

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I don't remember writing that exactly

Word for word.

Good info, fits exactly with the reported issues the Opal had.



it's almost as good as one of mine

Do we get to see that, or co-ordinates?


Have you investigated faster ways of making these - maybe like a rolling punch? Sell it by the roll. Let the builder cut off as much as needed for each rib - or wherever it might be used.
No need for faster, it's cheap, convenient and ultra reliable as it is now, and importantly they are cut from the same sheets as other parts at the same time.

I can laser up to 3 meter lengths, but have no need.

Thanks for the thought.
 

TFF

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The Pelican or the AV 22 would be great for simplicity of building parts count and storage or just plane cool, but the elephant in the room is test flying. A sorted plane would be great to own, but the actual testing is going to scare most pilots if flying a plank for the first time. That can be a bigger problem than just building one.
 

Victor Bravo

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Sorry to appear like I'm imposing my thought process on the entire group (my wife says I have been known to do that)... but...

To my understanding we are not talking about Part 103 here on this thread. That's a tall order for any flying wing. Achieving 103 weight and stall speed means a wing with a lot of lift, meaning camber, meaning a tail. I believe this discussion is better served if we do not make Part 103 a parameter, but again I cannot speak for anyone but me. We are of course talking about something that's LSA compliant, but let's face it LSA just became about 3/4 irrelevant on May 1.

To my understanding we're talking about an airplane suitable for a pilot with basic flying skills; not a brand new wet ink private license but not Tony LeVier either. We don't need a 30 mph landing speed,a nd we sure as hell don't want any sort of a sharp stall. Higher XC speeds and sharp stalls move this discussion towards the 21st Century Facet Opal for the moderately advanced pilot. That's a totally valid, but totally separate, design exercise.

My comments on the Opal were not meant in any way to disparage that airplane, I only meant it would be a little "hot" for a low time pilot, and most all of the magic in that airplane would go away with fixed gear and a blunt airfoil. The Facet Opal was designed from the start as a record setting aircraft, and all the compromises were aligned for that. IMHO for those people thinking about a constant chord version of this design exercise, the Backstrom platform is the better starting point.

Cheapracer's comment about moving the ailerons closer to the CG makes a lot of sense. A tapered wing can also be a little lighter structurally, or have a little more structural margin for a given weight.

Others have brought up molded composites, which is absolutely another viable option. Per my previous post, this comes at a measurable increase in infrastructure and startup cost, and a part of the OP's parameters were cheap and simple.

My comments about the materials going right to the CNC shop and then being shipped to the customer were accidentally limited to making a direct comparison to shipping a molded fuselage. To answer Fritz' question, yes, formed ribs would take up more space than flat sheets, and I accidentally left that out of what I wrote. The two options that seem most obvious to me are to simply ship out another box with the formed ribs (which would be smaller than a box of foam ribs, or hot wired cores, or molded skins).... OR... use the idea that Cheapracer and I had each thought of (the rivet-on structural rib capstrip). That choice can be the subject of a separate analysis of parts count and number of assembly operations vs. mfg. and shipping cost. The bent angle rib caps can be nested together and go into the shipping tube with the other extrusions, bars, tubes, etc. Hydroformed or rubber-block-formed ribs would need a box.

One of the ideas that I would employ on this, if I were trying to go into business making and selling a kit for this, is to build different options into the design that allowed for non-structural molded composite top and bottom fuselage fairings vs. flat wrap sheet metal vs. you-carve foam blocks. It seems that a basic square (structural) fuselage would be designed, and then you could offer the customer a range of options from the cheapskate to the expensive. There are people who really need to save every penny otherwise the whole thing is not doable. There are scroungers who want to substitute time for money. There's old model airplane bums like me who would make fuselage fairings out of the "foam and tape" method. Fritz and others will cheerfully point out that Evans offered this same concept on the original Volksplane, showing three or four different cosmetic fairing versions of the fuselage that are left up to the builder.
 

Hot Wings

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To my understanding we are not talking about Part 103 here on this thread. That's a tall order for any flying wing..
For me personally If I start serious calculating and CAD it will be part 103 compliant. Done enough to know it's possible - and not give up too much in the way of practicality. But for the purposes of this thread part 103 compliance is not required.


One of the ideas that I would employ on this, if I were trying to go into business making and selling a kit for this, is to build different options into the design that allowed for non-structural molded composite top and bottom fuselage fairings vs. flat wrap sheet metal vs. you-carve foam blocks. It seems that a basic square (structural) fuselage would be designed, and then you could offer the customer a range of options from the cheapskate to the expensive. .

This takes more engineering but it's also the plan I have stuck in my head. Make the design somewhat modular so that the sub assemblies would interchange at well defined points. The slab sided tin or moldless home brew fuselage would bolt to the same spar attach fittings as the factory built stretch formed aluminum or molded composite fuselage.
 

Victor Bravo

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What is the big draw of Part 103 for this type aircraft?

I would sure as heck not want this little airplane to be operated by someone who hasn't had basic "airplane" or glider training. It will be faster, "cleaner" and more responsive that most UL types. Probably 50-80% faster than the UL limits. Making it a huge kite (to meet the 103 stall limits using a reflexed airfoil) will result in an airplane with awfully low weather limits and no upwind penetration.
 

Hot Wings

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What is the big draw of Part 103 for this type aircraft?
Maybe I've got this backwards, but it's not a plane looking to be part 103 but what plane is 'best' for part 103. I just happen to think that a flying wing can be made to fit within part 103 better/easier than any other layout - at least with regard to weight. Yes, it will be far cleaner than most existing part 103s but that isn't a problem at all. In fact it's a big bonus. The speed limit can be artificially limited by several methods all of which the FAA is comfortable with - just as long as the pilot can't override while in flight.

The stall speed might also be handled without becoming a 'kite'. That part of the problem is, admittedly, not as easy to solve. Meeting the strict letter of the regulation is harder. Being compliant with the formula method given in the AC is not as onerous. I think, not just believe, it is possible.

If one is seriously considering the kit side of this then part 103 means the ability to market sub 50% kits, even complete flying aircraft if one wants.

A properly engineered part 103 wing designed to utility load factors is probably close to normal category load factors for an LSA. Just remove the speed restriction device and you have a decent LSA.

If you can find any holes, stick your finger in and and rip away...... That is one reason I started this thread.
 

vtul

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No reason it can't be fully sheeted, or at least the top side. That is unless you want one version to remain part 103 legal - which is something I personally would like to see.
That was what I had been responding to.

But I later heard that it needed to fit LSA, so the return now to UL is confusing.

I see it as very different design requirements. Again, what are we discussing?
 

vtul

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The speed limit can be artificially limited by several methods all of which the FAA is comfortable with - just as long as the pilot can't override while in flight.
Is there a means other than limiting engine power that is acceptable to the FAA? Just curious, not doubting.
 

addicted2climbing

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A guy who had worked with Jim Marske, a Canadian fellow named Mat Redsell, had developed or flight tested exactly such a device on the Marske Pioneer 2. He had a crank or clothesline mechanism, which ran a battery or lead weight back and forth in the fuselage to trim it for static balance AND flight trim. Apparently it worked exceptionally well, and resulted in measurable performance gains. A well known builder and proponent of the Marske flying wings, USAF General Mike Hostage, was also reported to be testing something like this on the Pioneer 3.

One of the race modification shops and I did testing years ago on sailplanes (non-flying-wing types) with adjustable balance, using a separate water ballast tank in the vertical fin. It allowed (otherwise unsafe) rearward CG conditions, which delivered very noticeable gains in some flight modes (also delivered some underwear changes in other flight modes...). We could take off at the certified aft CG limit, then dump water out of the forward ballast tanks (wings), and then dump water out of the tail tank to return the CG to the certified range.

Years before this, there had been testing done on open class sailplanes (about when the Nimbus 3 came out) up in Minden NV where a block of depleted Uranium (really) was mounted on a steel tube in the fuselage and moved back and forth by means of a crank. Dick Brandt is the name I have a distant memory of.
I have a video Mat Redsel sent me of him testing the sliding weight on his modified Monarch 11. He also did a bit of other flight testing in the video. He found that the sliding weight worked well. However on landing, he came in a bit harder than expected and was a bit surprised about it. Then he looks and realizes he forgot to return the weight back to the landing setting. The video is on my desktop and if I find it will post it here.

Also I spoke with Jim a few years ago and he said not to use the Fauvel Airfoils as he found they had some serious drawbacks. He developed his own and they are likely available if people ask. He is working on a follow up to his little yellow book with more up to date findings but unsure when it will be available as its not a big rush on his end.

Marc
 

plncraze

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Marks thought there was too much reflex in the Faucet foil. His RLM foil is on UIUC
 

lr27

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Regarding c.g. sensitivity, a delta wing may not have that problem. I seem to recall Barnaby Winfan saying he flew to Oshkosh with a case of oil behind him. I'm not sure, but I think it wasn't even right up against the seat. Hans Nieubert and Wainfan wrote a paper about a low cost, facetmobile style aircraft, which you can find at facetmobile.com Considerable thought was put into the manufacturing end. As I recall, their concept is based on cutting up a standard sandwich panel to make up most of the airplane. I'm thinking this could go with some kind of tab and slot arrangement to minimize jigging. Perhaps, for the homebuilder, a CAD file could be provided to take to an NC vendor to get all the big parts cut to start with. As written, it's based on a Facetmobile style shape. However, I wonder if, with a thinner panel material, it couldn't be made into a smoothmobile. Or possibly just something that looked like a Dyke Delta. Folding could use the Dyke Delta or some other approach. The wing would be quite deep, so folding and latching mechanisms might be quite a bit lighter than on a conventional machine. Possibly some kind of nesting. The weight penalty for making things a bit stronger than necessary would be relatively small, I think, possibly allowing moderate screwups without making an unsafe aircraft.

One advantage of a Facetmobile or Smoothmobile is a very roomy airplane. Wainfan said that, on the FMX-4, he could extend his arms fully to each side. He also said a 4 passenger version would be bigger on the inside than a Winnebago. Another advantage is that, according to what Wainfan said, the ride is much smoother than you'd expect from something with such a low wing loading. I could see something like this in commercial service for bulky, light cargo. A disadvantage of such an aircraft is that you'd probably want to carry some kind of anchors and strong tie down gear! Plus, if you wanted to put it in a hangar, you'd really need that wing folding device.
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As far as part 103, if you can find a really lightweight covering, a lot of wing area shouldn't be a huge problem. The formula in Appendix 1 means that you can have a bit more horsepower if you have more wing area. It would also pay to make control surfaces somewhat larger, though the returns are moderate. Then you can use two pairs of partially enclosed wheels, each pair in tandem. Careful review of Appendix 1 may reveal tradeoffs that might allow your airplane to go 75 or 80 mph. Appendix 2's short cuts require "relatively square, rectangular wings; they are not valid for noticeably swept or tapered wings." Reading this, some years ago I came up with a concept for an ultralight with a wing that was literally square. To avoid problems with torsional vibration in the redrive, I decided a very long belt would be nice, to get the oscillating frequency below idle speed. With a long belt, a tip mounted prop on each end of the wing might be practical, reducing the induced drag of a short wing span. I suppose this concept could work without that additional complication, but it appealed to me. Elevators would be mounted outboard, a la V-173 and perhaps modeled on Volksplane tail surfaces, as would the rudder or rudders. Thus, you'd have a configuration like a square V-173. I suppose the outboard props might be omitted if one could get the power allowed high enough.

Threads discussing this:
another low aspect ratio idea https://www.homebuiltairplanes.com/forums/showthread.php?t=7136
The above thread shows the beginnings of the idea. I'm sure I've discussed it elsewhere on HBA, but I don't remember where.

I'd forgotten that I'd started to work up a CAD model, which might give a better idea of the configuration. I'm not all that happy with the landing gear yet. Remember that the model is still very crude and a real one would definitely look different.
picture ultopassy012414.jpg



A relevant aircraft that isn't discussed much:
https://en.wikipedia.org/wiki/Baker_MB-1_Delta_Kitten
 

FritzW

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What is the big draw of Part 103 for this type aircraft?.
I agree with HW, I think this type of airplane could be very light, which is always a good thing. For me the fact that it meets part 103 is just icing on the cake.

I have no interest in it's marketability, I just think it could be a cheap, easy, simple, good flying airplane that I'd like to build. ...not to mention being under part 103 keeps the government out of my Saturday morning fun flying. ;)
 

pictsidhe

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The power limits in 103 only apply over 55knots. Below that 1000hp would be legal. A restrictor triggered by airspeed is legal.
I'm working on a low drag nurflugel. On legal power, speed will be above 55kn, but climb would be lousy. It'll probably have about 50% extra power and an airspeed activated power restrictor.
Prone pilot, wing warping. Probably too weird.
 

Sockmonkey

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I think a Warren truss wing can be done with a minimum of parts.
This shows the total number of different parts needed.
The little prism-shaped bits are so you don't need to worry if the rib you grabbed is a lefty or righty, though two different rib types isn't much of a hassle anyhow.
Even the aluminum skin of the wing would help structurally by preventing the ribs from buckling.

 

rotax618

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My plan would be a flying wing, aspect ratio approx 1.3-1.5. Tractor configuration with Straight leading edge, Tapered or curved trailing edge. 5 metre span, tail dragger undercarriage, folding wing with a legal towing width centre section.
The craft would have a part 103 minimum speed (planform not known to stall), top speed could be limited if necessary.
Simple folding wing hinge the same as Flying Flea.
Could be built very light (part 103) would have good access (walk up the wing), good forward visibility.
Shouldn't look too weird and shouldn't be a handfull for low time pilots. Low parts count means lightness nd simplicity.
Planks are exceedingly sensitive to CG and pitch dampening is low (PIO), deltas have very poor visibility unless you can see throught the floor and access is a problem ( trapdoor under).
It is really a no-brainer.
 

Beragoobruce

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My personal preference is for composites, but I have to agree that for mass market appeal sheet metal is probably the ideal for a combination of plans built and kit supplied parts. For a full factory built part 103 then composites might be the winner. Either way a composite fuselage shell just makes things look right. Find a way to do that in sheet short of stretch forming and I'll be a supporter.



The ARV Super 2 did just that. See this youtube for a view of the fuselage. Between the main bulkhead & the firewall, the structure comprised just 4 pieces of superformed aluminium: a floorpan; 2 side panels, & a coaming: https://www.youtube.com/watch?v=i1iVvEb_eAk

The process used Superplastic aluminium. This is ally modified with trace elements (Lithium, ISTR), which makes it flow plastically at around 500ºC. It is then formed over a female mould using gas pressure. In this way all sorts of fine detail can be included at no additional cost or weight penalty. See http://www.superforming.com/ & others.

The objective was to gain the styling advantage of composites within an all-aluminium airframe structure. to this end, all joining of panels throughout was done using adhesive. But the CAA certifying authority insisted on some rivets, so in the original factory aircraft what rivets that were used were countersunk. This gave very clean lines.

ARV was the first - and maybe still the only - light aircraft to use superplastic aluminium in primary structure. The plane was a joy to fly, but failed due to greedy bankers and over ambitious company growth assumptions.

Bruce
 
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