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

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Island_flyer

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I like the relatively good ergonomics of the seat. Some seats for ultralights require the knees to be bent way up (with the feet just slightly forward of the knees, though lower), and focus almost all of the weight onto a very small portion of the victim's posterior which, even with padding, can get very uncomfortable after 20 minutes. In this design the legs and back share the load, distributing the weight more comfortably.
 

J.L. Frusha

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I like the relatively good ergonomics of the seat. Some seats for ultralights require the knees to be bent way up (with the feet just slightly forward of the knees, though lower), and focus almost all of the weight onto a very small portion of the victim's posterior which, even with padding, can get very uncomfortable after 20 minutes. In this design the legs and back share the load, distributing the weight more comfortably.
The seat design came from a glider. I've been toting that pic for years, then I came across the AiRecliner idea by @Victor Bravo...
 

Riggerrob

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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.

Amusing how several Russians were able to built elevon "mixers" (BOK-5 and disco-plane) using only cables while Western designers seem to need complex weldments.
Note that V-tails need similar "mixers" to convert yaw (rudder pedals) and pitch (control stick fore and aft) into appropriate rudder-vator movements.
 

Riggerrob

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I dunno VB. For me aviation is like sex. It's a great and wonderful thing if your in love. But if you try to do it for money, you're customers are never the folks you hoped they'd be and even if you make a few shekels you won't respect yourself in the morning. ...Uncle Sam pimped me out on C-130's for almost 30 years, that's a kind of dirty that just won't wash off :roll:

I had the same experience working as a tandem skydiving instructor. I got into the business early (1984) and stuck around until 2019.
 

WINGITIS

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The ARUP model has a better airfoil than the OPAL, for the size of those models..

Reynolds Numbers are in the 225,000 to 450,000 for the OPAL at lowish to medium speeds and the airfoil in the plans could be upgraded...

FACET OPAL RC AIRFOIL 175%.png FACET OPAL RC MODEL AIRFOIL ANALYSIS.png
 

rotax618

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I have reported this before, I was at Evans Head Airport when Scott broke those records, I observed the Facet Opal take off, if you have have ever flown a Control Line combat wing you would be familiar with the pitching and weaving PIO you get immediately after launch, until you get complete control - the Opal did exactly that - Scott was a very skilled pilot, the Opal was not a low hour pilot’s airplane. My advice, in the interest of flyability, if you design a similar plank, either decrease the aspect ratio or increase the pitch dampening - or both. It is not hard to imagine that the airframe could have been subjected to high G load at speed with an abrupt pitch change.
 

WINGITIS

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Here is the ARUP model airfoil at its greatest Chord, which is nearly 3 times that of the OPAL airfoil, so a greater RN number 1300000 versus the 450000, both at 45 Knots.

ARUP MODEL AIRFOIL 85%.png ARUP MODEL AIRFOIL AT ITS HIGHER CHORD RN MUMBER.png
 

WINGITIS

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Here are the DAT files, renamed to TXT.
 

Attachments

  • FACET OPAL RC MODEL SPLINE 295 0.2TE 3.5 DEG UP TRIM FRISE.txt
    7.7 KB · Views: 11
  • FACET OPAL RC MODEL SPLINE 299 0.2TE.txt
    7.6 KB · Views: 4
  • ARUP MODEL AIRFOIL SPLINE 299 0.4TE.txt
    7.6 KB · Views: 7

cluttonfred

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On the Reynolds number, I get this for the Arup:

Velocity 23.15 m/s 45.0 kt 51.785 mph 83.34 kph
Chord width 0.866 m 2.8412 ft 34.094 in
Reynolds Number 1,411,128

The Incomplete Guide to Airfoil Usage lists a the Arup airfoil as a modified NACA (Munk) M-6, which is here if anyone is looking for the general properties.

 

WINGITIS

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On the Reynolds number, I get this for the Arup:

Velocity 23.15 m/s 45.0 kt 51.785 mph 83.34 kph
Chord width 0.866 m 2.8412 ft 34.094 in
Reynolds Number 1,411,128

The Incomplete Guide to Airfoil Usage lists a the ARUP airfoil as a modified NACA (Munk) M-6, which is here if anyone is looking for the general properties.

Measured from the actual plans/scale I got 2.842 feet

Which is 1,365,555

I rounded it down to 1.3 because that was the length of the longest rib, the others are progressively shorter and have less effective area..its just a visualization.

I know the full size ARUP airfoil is an M6, BUT I am comparing what the plans are for the model, what would be built....

As you can see they are not exactly the same as drawn....

As you can see from the analysis the M6 does a little better than the "AS DRAWN" version does.RN NUMBER FOR ARUP MODEL AIRFOIL.png ARUP MODEL AIRFOIL VERSUS M6.png ADDED M6 TO ANALYSIS.png
 
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Victor Bravo

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The thread title has the words "basic, cheap and simple".

You can all shoot poison darts at my picture if you like, but to me, these primary parameters mean:

Straight spar
Average piloting skills
No wild pitch excursions "until full control is achieved"
Fixed gear
Benign low-speed handling
Thick, turbulent flow airfoil
Common, non-toxic materials and construction practices

So the top choices are fairly obvious, Backstrom and Fauvel/Debreyer.
 

Sraight'nlevel

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Measured from the actual plans/scale I got 2.842 feet

Which is 1,365,555

I rounded it down to 1.3 because that was the length of the longest rib, the others are progressively shorter and have less effective area..its just a visualization.

I know the full size ARUP airfoil is an M6, BUT I am comparing what the plans are for the model, what would be built....

As you can see they are not exactly the same as drawn....

As you can see from the analysis the M6 does a little better than the "AS DRAWN" version does.View attachment 122146 View attachment 122147 View attachment 122148
You are not considering the Cm effects.

 

cluttonfred

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I would go even further to say that, for "a cheap and simple option for basic fun flying" a Backstrom plank of relatively low aspect ratio is the way to go. Period. I don't see how you can get any simpler and easier to build than a constant-chord wing, two elevons and one rudder. Exactly how low you take the aspect ratio comes down to how much power you have, what sort of performance you need, folding or removable elements, and both workshop and storage concerns

There could be an argument for higher aspect ratio if the goal is to store or trailer *spanwise*. Overall length of Backstrom's EPB-1C is just 2.54 m (8' 4")! It's easy to see how folding or removing the rudder would get you down to 8' for trailering, or even 7' to fit through a shipping container door with some tweaks to the design. A somewhat upright "kitchen chair" seating arrangement would allow space for an two-stroke engine in the nose or the engine could be raised above the pilot's feet like an original Pou-du-Ciel or set up as a pusher.

EBP-1C_NSM.jpg KN_Backstrom_EPB1c-1964.jpg

EPB-1C
Span: 8.08 m
Length: 2.54 m
Minimum sink rate: 1.2 m/s @ 80 km/h
Aspect ratio: 6.5
Best glide ratio: 19.8 @ 111 km/h
Wing area: 9.86 m²
Airfoil: modified Abrial
Wing loading: 18.8 kg/m²
Seats: 1
Empty weight: 97 kg
Gross weight: 159 kg
Ballast: none
Construction: wood and fabric

Source: Backstrom EPB-1

The thread title has the words "basic, cheap and simple".

You can all shoot poison darts at my picture if you like, but to me, these primary parameters mean:

Straight spar
Average piloting skills
No wild pitch excursions "until full control is achieved"
Fixed gear
Benign low-speed handling
Thick, turbulent flow airfoil
Common, non-toxic materials and construction practices

So the top choices are fairly obvious, Backstrom and Fauvel/Debreyer.
 
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