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

[daveklingler]

VB - I think I am enrolled in your class professor.

Does this aircraft have any use?

We seem to all agree the above is not worthwhile but I keep coming back to it.

This reminds me of a example from engineering school. A classmate was visited by a traveling salesman trying to keep afloat a home insulation business.

The newly married student had recently purchased a turn of the (20th) century uninsulated home. He pulled out heating oil receipts and did the math showing that it would take nearly fifty years to pay for the insulation the salesman was selling and he sent the sales man packing.

However, in his engineering mind he knew that the improved comfort and economy was a good thing, he just could not prove nor justify it.

Within two years the cost of heating oil was rising and soon was well above the ten cents a gallon used in the example. It is very likely that the house survived the Detroit riots and it may be still standing this day.

Conclusion: If the results are questionable so are the engineering assumptions and vice versa.

PS: I think there may be a market for a tail wheel conversion on a C-172. There is one available for my sons 175 but as you say it’s cost benefit numbers do not work out.

Good engineering generally relies on good starting parameters. Good starting parameters rely on imagination and perspective.

In your example, the engineering student forgot what the house was actually for (er...living in), but in his defense, maybe he had to live in an uncomfortable, drafty house for a few years to expand his mind.

Or he didn't realize he could get quotes and very likely beat the salesman's price. Or do the easy parts, like the attic, himself. Or figure out what parts would be most cost-effective (begin with the most leaky windows).

Bottom line: his starting assumptions gave him incorrect results. Sometimes you have to step way, way back and ask yourself, "What was the goal, again?"

"Oh, that's right! To fly cheaply!"

 

[daveklingler]

Crud.

I always hit "reply" instead of "edit."

 

[Hot Wings]

Bottom line: his starting assumptions gave him incorrect results. Sometimes you have to step way, way back and ask yourself, "What was the goal, again?"

"Oh, that's right! To fly cheaply!"

This whole thread that I started could well be used as an example of a faulty starting assumption.

Not to create thread drift - a simple gyroplane might well fit the same mission of a small flying wing and do it even better?

Rather expensive part 103 example

 

[Sockmonkey]

It's neat but any time I see something with a sleek body shell, I know they've missed the point of something being inexpensive and added a lot of non-vital refinements that jack up the cost.

 

[rotax618]

Erkki67, I agree it looks good but I recon that to get prop clearance the UC would be quite long - a better arrangement would be to mount the engine on the wing leading edge as quite a bit of drag is generated by the wing, the UC could be much shorter and it may be more easily stored in a domestic garage, it would also be easier to design from a structural view point.

 

[rotax618]

Hot Wings is correct, a gyro could perform the intended mission. Gyros and LAR aircraft share a number of characteristics, they are both stall and spin resistant and have a steep approach and require a flair for aerodynamic braking. The advantages the LAR has is it doesn’t require 1/2 of its weight in thrust just to fly and it can go negative ‘G’ without catastrophic result and is far more efficient in use of thrust and a higher cruise speed.

 

[erkki67]

Ok engine at the leading edge, whole aircraft from the spinner to the trailing edge of the rudder not longer than 98”, an aspect ratio of 3 and the my beloved Fritz style fuselage below the wing!

 

[erkki67]

This fuselage below the wing

 

[nestofdragons]

This starts to look like the project of a contact of me. He is making the Sky Scooter. Ok, no flying wing, But ... loooow cost as goal.

 

[erkki67]

The engine position like on this idea.

 

[erkki67]

This starts to look like the project of a contact of me. He is making the Sky Scooter. Ok, no flying wing, But ... loooow cost as goal.

Are those the gentlemen of the Scirocco?!

 

[nestofdragons]

Are those the gentlemen of the Scirocco?!

Indeed, these are the people of the modern edition of the Scirocco. A guy with experience in composites. And now with a eye for really really basic flight. Going further basic gets us to a broomstick.

 

[Hot Wings]

The advantages the LAR has is it doesn’t require 1/2 of its weight in thrust just to fly and it can go negative ‘G’ without catastrophic result and is far more efficient in use of thrust and a higher cruise speed.

And this is where we get into sub-missions. The Gyro has a few other disadvantages, such as blow over while taxi and tail strikes if the rotor isn't managed properly. Other quirks particular to individual design pop up as well, just like fixed wings.

On the flip side the gyro is far easier to dissasemble for transport on a trailer, requires a much smaller trailer, isn't as susceptible to structural damage during transport and stores in a much smaller space. View is generally better than from a FW or LAR.
Efficiency is less in cruise, in some cases much less. After all they are still using 1920's technology in the design of the rotor. Power is/was cheap. Design of a rotor is complex. We could do better but the market just doesn't justify the cost.

 

[Sockmonkey]

And here we are.

 

[cluttonfred]

Neat, Sockmonkey! Personally I'd suggest much shorter elevons, say 40% of the half-span with 10% of the wing outboard (your darker blue tips) and 50% of the wing inboard without elevons. That would help the inboard 50% of the wing provide maximum lift at low speed and stall before the washed-out section near the tips and elevons. You might also consider a more Hoerner-like tip that would require no composites, just a tip rib extrapolated from a 45-degree slice of wing and then set at 45-degrees to a normal perpendicular end rib and covered with fabric. Also, while I admire the rectilinear simplicity of your rudder, it looks awfully small and something like the straight-cut, balanced rudder on a FRED (obviously changed in proportion to suit your sketch) would work well.

 

[erkki67]

Sockmonkey, I agree with cluttonfred, the tail would tapper upwards .
a Landing gear like on the Skypup and there we go.

 

[Sockmonkey]

Wheee!

 

[Riggerrob]

This starts to look like the project of a contact of me. He is making the Sky Scooter. Ok, no flying wing, But ... loooow cost as goal.

Pretty Skyscooter!
How about folding that tail boom sideways ... so that it lays under the wings' trailing edge?

 

[Sockmonkey]

More changes.

 

[erkki67]

Sockmonkey, na, the taildragger is by far the better variant
The Rudder has to remain in the stream of the propeller!