Quantcast

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

HomeBuiltAirplanes.com

Help Support HomeBuiltAirplanes.com:

rotax618

Well-Known Member
Joined
Oct 31, 2005
Messages
989
Location
Evans Head Australia
Circular wingtips may be better - refer to Charles Zimmerman’s NACA study on low aspect wing with a Clark Y airfoil at Langley Research Centre.
 

Sockmonkey

Well-Known Member
Joined
Apr 24, 2014
Messages
1,952
Location
Flint, Mi, USA
I've read up on Zimmerman's work and how deltas generate vortex lift, but it mostly concerned high-power STOL applications rather than reducing vortex drag.
 

Hephaestus

Well-Known Member
Joined
Jun 25, 2014
Messages
1,816
Location
YMM
Circular wingtips may be better - refer to Charles Zimmerman’s NACA study on low aspect wing with a Clark Y airfoil at Langley Research Centre.
Circular isn't bad, the elliptical I started with seems marginally better marginal - but span increase to maintain same area.

I tried the Wittman w10 style treatment - that was worse than square tips. Big end plates - (about the wings thickness in excess around) was in the range of the elliptical. Horner wasnt much better than square. Tip "tanks" actually wasn't awful.

This is how I ended up in this horrible test/adjust/test/adjust infinite loop. 😂
 

Hephaestus

Well-Known Member
Joined
Jun 25, 2014
Messages
1,816
Location
YMM
I've read up on Zimmerman's work and how deltas generate vortex lift, but it mostly concerned high-power STOL applications rather than reducing vortex drag.
There's a couple lifting body articles that'll give you better ideas. I'll have to dig when I'm at the hangar next, it's in a pile of reference material, one of the articles gets into tip vortices I think I think it was addressing a yaw oscillation issue. Articles mostly useless but there's 2-3 useful pages.
 

nestofdragons

Well-Known Member
Joined
Jun 8, 2016
Messages
381
Location
Near Antwerp, Belgium
You know, for a LAR plank I'd be tempted to steal an idea from Nestofdragons and stick those multi-winglets on the tips to reduce the drag. Don't know if that would be better than Hoener tips or not.
One other thing that might work or not would be to add the tiniest bit of forward sweep at the tips.
Happy to see i inspire people. ;) I can tell you that a engineer i know did a study about those feathers on my demand and he was surprized by the stability at low speeds. And it was confirmed in the past by a guy who made throw models. They are really stable, he told me. Could be good for a beginner-airplane or observer.
BirdWing - Nest of Dragons
birdwing.jpgbirdwingdetail1.jpg
 

Sockmonkey

Well-Known Member
Joined
Apr 24, 2014
Messages
1,952
Location
Flint, Mi, USA
I'm not suggesting any particular configuration... Just pointing out a source of a lot of good experimental data. You can get a lot of insight from reading some of the reports.
There's a couple lifting body articles that'll give you better ideas. I'll have to dig when I'm at the hangar next, it's in a pile of reference material, one of the articles gets into tip vortices I think I think it was addressing a yaw oscillation issue. Articles mostly useless but there's 2-3 useful pages.
Thanks guys.
Happy to see i inspire people. ;) I can tell you that a engineer i know did a study about those feathers on my demand and he was surprized by the stability at low speeds. And it was confirmed in the past by a guy who made throw models. They are really stable, he told me. Could be good for a beginner-airplane or observer.
What do you think would happen if you took it to a greater extreme? narrowing and stretching the fuselage and adding more winglets so it resembles a flying centipede?
 

Aerowerx

Well-Known Member
Joined
Dec 1, 2011
Messages
5,623
Location
Marion, Ohio
Hmmm.

I've been thinking about this for the last few days....

Instead of reinventing the wheel----I mean wing, look at birds. Copy what they do. They have been perfecting the designs for tens of thousands of years now.

Of course you would have to consider the "mission requirements".

Long distance cruising....Geese, Albatross
High speed maneuvers.....Swallows
Floating around....Vultures, buzzards

From Wikepedia
1593801259041.png

Another interesting article, which I have not completely digested yet.
 

Hephaestus

Well-Known Member
Joined
Jun 25, 2014
Messages
1,816
Location
YMM
Hmmm.

I've been thinking about this for the last few days....

Instead of reinventing the wheel----I mean wing, look at birds. Copy what they do. They have been perfecting the designs for tens of thousands of years now.
Problem there is the innate variable and flexible geometry birds are able to make use of.

Currently nearly impossible to duplicate.
 

erkki67

Well-Known Member
Joined
Feb 18, 2010
Messages
2,289
Location
Romont / Fribourg / Switzerland

Sockmonkey

Well-Known Member
Joined
Apr 24, 2014
Messages
1,952
Location
Flint, Mi, USA
Hmmm.

I've been thinking about this for the last few days....

Instead of reinventing the wheel----I mean wing, look at birds. Copy what they do. They have been perfecting the designs for tens of thousands of years now.

Of course you would have to consider the "mission requirements".

Long distance cruising....Geese, Albatross
High speed maneuvers.....Swallows
Floating around....Vultures, buzzards

From Wikepedia
View attachment 98886

Another interesting article, which I have not completely digested yet.
Problem there is the innate variable and flexible geometry birds are able to make use of.

Currently nearly impossible to duplicate.
An important factor is if said bird is flapping or gliding/soaring most of the time, and what sort of takeoff mechanics they use.

I would ignore the smaller species as they enjoy the sort of high power/weight ratios that let you get away with aerodynamic murder. I've seen chickadees use a burst of flapping to give them enough speed to then go full Angry Birds by cruising along on pure momentum for a second or two with their wings folded like a chirpy ballistic missile.

The larger, heavier species operate under the tighter constraints that force you to fully optimize for you flight regime.

For a cheap, simple, fun flyer we want something compact for storage with a fairly slow and short takeoff run. We can sacrifice a high top speed.
The large-ish birds that match that are chickens, turkeys, pheasants. They use low-aspect wings with heavily slotted tips.
Basically the thing Nestofdragons posted.
If we can deal with the tip drag in a fairly cheap and easy to build way, we're golden.
 

jedi

Well-Known Member
Joined
Aug 8, 2009
Messages
2,225
Location
Sahuarita Arizona, Renton Washington, USA
An important factor is if said bird is flapping or gliding/soaring most of the time, and what sort of takeoff mechanics they use.

I would ignore the smaller species as they enjoy the sort of high power/weight ratios that let you get away with aerodynamic murder. I've seen chickadees use a burst of flapping to give them enough speed to then go full Angry Birds by cruising along on pure momentum for a second or two with their wings folded like a chirpy ballistic missile.

The larger, heavier species operate under the tighter constraints that force you to fully optimize for you flight regime.

For a cheap, simple, fun flyer we want something compact for storage with a fairly slow and short takeoff run. We can sacrifice a high top speed.
The large-ish birds that match that are chickens, turkeys, pheasants. They use low-aspect wings with heavily slotted tips.
Basically the thing Nestofdragons posted.
If we can deal with the tip drag in a fairly cheap and easy to build way, we're golden.
This is what I proposed in the soaring section "Does this aircraft have any use?" thread.

The consensus was that there is not sufficient interest in this configuration (LAR* with multiple winglets) to justify further development.

One comment mentioned that it would need to be complimented with at least self launching power assist which I agree with but the low speed / maneuverable characteristics in general were not where the demand is. Pilots in general are more interested in going someplace rather than floating around in circles looking for food.

If there is further interest in the raven/vulture configuration I would like to participate. Otherwise my interest is directed more towards the falcon/gull/pterosaur planform.

IMHO this thread needs guidance as to whether it is headed towards the flying squirrel/saucer AR<1.5 or the LAR bird etc. (AR>2.0) or, is there a sweet spot at <1.5 but <2.0.

* LAR as in Low Aspect Ratio (AR) not Looks About Right.
 
Last edited:

rotax618

Well-Known Member
Joined
Oct 31, 2005
Messages
989
Location
Evans Head Australia
If you haven’t read Henry Mignet’s book Sport de L’Air, I suggest the you do. His words are inspiring and his enthusiasm is infectious. You can download it here.
The point is that people do aspire to build and fly machines just for the sense of achievement with no particular “mission” in mind. A simple airplane that could be built from locally available materials in a short timeframe, stored at home and safely flown perhaps only locally from a nearby field is the dream of many.
You could consider the Flea to be a slotted LAR wing, I have built a Flea and found it uncomfortable to fly but there are many features of the Flea that deserve a second look - the philosophy behind the idea is certainly one.
 

Hephaestus

Well-Known Member
Joined
Jun 25, 2014
Messages
1,816
Location
YMM
The consensus was that there is not sufficient interest in this configuration (LAR with multiple winglets) to justify further development.
In glider form - you'd have your work cut out absolutely :) Glider folks are all about the aspect ratio.

But I bet a ultralight foot launched glider that could be transported more easily or with that self launch as you mentioned - could be a good place to start making inroads.
 

Lendo

Well-Known Member
Joined
Feb 6, 2013
Messages
540
Location
Brisbane
Rotax 618- Hello from Brissie! The following as I see it.
The Tapered Wing is a Tad closer to elliptical than a 'Hershey Bar' wing, therefore a Tad more efficient,
However a straight leading edge and a straight trailing should give the least distortion of what the air experiences as it travels over the Wing and therefore even Vortices at the TE.
A Swept LE is less efficient as it distorts the Airfoil shape that the air sees, and requires more area to compensate.
However a Tapered Wing has a smaller Tip and therefore less Tip Vortex.
A tip of zero size has little Tip Vortex of it's own but has the accumulated rolling-up of TE Vortices.
Different priorities for different designs.
Also Low wing Wing model would require considerably more Dihedral compared to a High Wing.
Jut my opinion from my own research.
George
 

Hot Wings

Grumpy Cynic
HBA Supporter
Log Member
Joined
Nov 14, 2009
Messages
7,369
Location
Rocky Mountains
IMHO this thread needs guidance as to whether it is headed towards the flying squirrel/saucer AR<1.5 or the LAR bird etc. (AR>2.0) or, is there a sweet spot at <1.5 but <2.0.
My initial thought when I started this thread was for it to be a specific fork in the road from the VP-21ish and 20ft Container Challenge type threads.
Something between the Pelican/Vampyre and the AV-36, or the Opal, was what I saw on my horizon.

But if it turns out that something with an AR under 2.0 meets the mission requirements the this OP has no objection to another fork in the road. :beer: :popcorn:
 

Sockmonkey

Well-Known Member
Joined
Apr 24, 2014
Messages
1,952
Location
Flint, Mi, USA
The possum wing has a three meter chord, and a six meter span. The internal diagonal of a shipping container is around 3.3 meters, and six meters is 19.6 feet. You could cram it in there if you remove the wing from the fuselage and take off the endplates.
 
Top