Concepts only: Doodles without numbers

[Floydr92]

I'm curious about the mission; ultralight, motor glider, ... ?

The ultimate target would be a sub 70kg ultralight (uk unregulated) but it might not add up weight wise. It will remain the target: 70kg empty, 20kts stall. Would be specified to a mtow of 315kg from a loads perspective so it can be flown as an SSDR microlight regardless of meeting the 70kg target or not.
Mission is maximum off-airport fun at minimum cost in a 3 axis machine, in a neat and easily stored package that can be kept in a garage and trailered easily.

 

[AeroER]

The ultimate target would be a sub 70kg ultralight (uk unregulated) but it might not add up weight wise. It will remain the target: 70kg empty, 20kts stall. Would be specified to a mtow of 315kg from a loads perspective so it can be flown as an SSDR microlight regardless of meeting the 70kg target or not.
Mission is maximum off-airport fun at minimum cost in a 3 axis machine, in a neat and easily stored package that can be kept in a garage and trailered easily.

That's a tough requirement for a rigid wing aeroplane.

Are there any rigid wing airplanes flying in this weight class?

Have you done any sort of weight estimates?

70 kg means pulling out all of the stops, a truly minimum air vehicle is required; along the lines of a Paul Macready philosophy- "if the part falls to Earth, it's too heavy" and "if the first part didn't break, it's too heavy". Probably possible if the maximum speeds are very low and the airplane is restricted from flying in anything but very light breezes and almost no turbulence.

You'll want to revisit the high aspect ratio wing.

 

[Floydr92]

That's a tough requirement for a rigid wing aeroplane.

Are there any rigid wing airplanes flying in this weight class?

Not that i'm aware of.

Have you done any sort of weight estimates?

Yes. My estimations, accurate to 3 decimal places are coming in on target although that could all change.

70 kg means pulling out all of the stops, a truly minimum air vehicle is required; along the lines of a Paul Macready philosophy- "if the part falls to Earth, it's too heavy" and "if the first part didn't break, it's too heavy". Probably possible if the maximum speeds are very low and the airplane is restricted from flying in anything but very light breezes and almost no turbulence.

You'll want to revisit the high aspect ratio wing.

High aspect ratio is actually the enabling factor here. Bear in mind it is strut braced so it doesn't require the sort of structure a sailplane would with a 30:1 cantilevered wing. This is 16:1, strut braced around 1/3rd so structurally equivalent to something like a 10:1 cantilevered wing (quick guess, easy to work out).

having a high aspect ratio does a few things but the important part is that in reducing cord, it reduces the wing volume to a level that solid foam core composite construction becomes feasible. Due to this ability to have a silky smooth wing with accurate foils allows much higher lift coefficients which then reduces wing size and weight. As a side benefit the increase in wing loading will result in better performance in unfavourable/turbulent/gusty conditions. it's not the weight that makes small planes horrible in these conditions, it's the low wing loading. Small changes in wind direction and or speed result in massive changes in lift. So fundamentally, the higher the CL the better. This one has a wing similar in section to a zenith ch701 stol. It has full span fixed slats and flaperons which in the Zenith achieves a CL upwards of 3! lower reynolds number will likely bring that down to circa 2.8 in my application.

The only way to really find out is to try, and if it fails and comes in over weight which i'm realistic enough to expect, then it will still be a useable aircraft for me in a different regulation class. I'm willing to give it a good shot, put my money where my mouth is and see if i can do it.

 

[cblink.007]

Some years ago, I once conjectured a 4+ place molded composite canard, similar in size/shape to the Velocity, pressurized cabin, air conditioned, powered by a converted diesel Audi pulled out of the wreck yard, superior and cheaper than everything else out there, had a grand plan about gathering investors, and planned to chronicle the whole development on YouTube for the world to see! No team to be seen...just me in every video.

Then I realized someone beat me to the punch....

There's your Friday humor!!

 

[AeroER]

Not that i'm aware of.



Yes. My estimations, accurate to 3 decimal places are coming in on target although that could all change.



High aspect ratio is actually the enabling factor here. Bear in mind it is strut braced so it doesn't require the sort of structure a sailplane would with a 30:1 cantilevered wing. This is 16:1, strut braced around 1/3rd so structurally equivalent to something like a 10:1 cantilevered wing (quick guess, easy to work out).

having a high aspect ratio does a few things but the important part is that in reducing cord, it reduces the wing volume to a level that solid foam core composite construction becomes feasible. Due to this ability to have a silky smooth wing with accurate foils allows much higher lift coefficients which then reduces wing size and weight. As a side benefit the increase in wing loading will result in better performance in unfavourable/turbulent/gusty conditions. it's not the weight that makes small planes horrible in these conditions, it's the low wing loading. Small changes in wind direction and or speed result in massive changes in lift. So fundamentally, the higher the CL the better. This one has a wing similar in section to a zenith ch701 stol. It has full span fixed slats and flaperons which in the Zenith achieves a CL upwards of 3! lower reynolds number will likely bring that down to circa 2.8 in my application.

The only way to really find out is to try, and if it fails and comes in over weight which i'm realistic enough to expect, then it will still be a useable aircraft for me in a different regulation class. I'm willing to give it a good shot, put my money where my mouth is and see if i can do it.

Build the airplane.

 

[nestofdragons]

This vid makes me think a CriCri triMotor would be interesting.....an extra 2-stroke on the nose......

Those russians keep amazing me. I start to like them a lot. They dare.

 

[poormansairforce]

reduces the wing volume to a level that solid foam core composite construction becomes feasible.

I'll ask you the same question I ask everyone else that thinks foam core construction and ultra lights go together..... have you done the math on how much that wing is going to weigh?

 

[Bigshu]

A quick Google search did not turn up any current info but are you aware of the difficulties and the move to MO?

I talked with them about a year ago and they had completed the move and were still in business intending to continue with the EMG-6 project.

Not sure where current income is coming from. I think they still do the UL/LS classes.

Video shown is from CA.

I think they still do the repairman classes for LSA. Could be Covid has put a damper on their business? I wish I could have got the Varga they traded when they made the move.

 

[AeroER]

I'll ask you the same question I ask everyone else that thinks foam core construction and ultra lights go together..... have you done the math on how much that wing is going to weigh?

No numbers in this thread. I looked for a thread dedicated to the vehicle and had no luck.

 

[Floydr92]

No numbers in this thread. I looked for a thread dedicated to the vehicle and had no luck.

Too early for that...

But yes in response to poormansairfoce's question, I have calculated wing weight based on skin, spar and foam volume inclusive of flaps and slats and have compared that to other known wing weights of similar size, both similar and different construction methods. Let's say it has given me confidence that it can be done. You're quite right though. Replicating a big fabric wing on alu ribs on tube spars out of foam cored composite would be silly. I'm not doing that. I'm increasing CL with a more effective wing, thus reducing area and volume significantly. Find me an ultralight with a 900mm chord and 16:1 aspect ratio made in the normal way and we'll compare apples with apples

 

[EzyBuildWing]

Just when I thought I'd seen everything.....this comes along:
ZEVA AERO - Zero-emissions Electric Vertical Aircraft

 

[J.L. Frusha]

Build the airplane.

If he builds it, they will come...

 

[J.L. Frusha]

Not quite a complete AiRecliner plan, but it's getting there...

 

[erkki67]

Not quite a complete AiRecliner plan, but it's getting there...View attachment 120595

View attachment 120594

How is this birdto be flown ?

 

[J.L. Frusha]

How is this birdto be flown ?

Normal 3-axis stick and pedals.

Considering the possibility of a Tensegrity wing structure for greater strength than regular ultralight wings at somewhat lower, or close to the same structural weight. Using the Junkers control surfaces removes any concern of wing integrity,that way. Of course, it complicates construction considerably, so it would be a trade-off.

 

[jedi]

Tensegrity wing structure

I would like to see doodles of the wing proposals.

IMHO - On of the advantages of the Tensegrity wing structure is the ability to eliminate ailerons and use the cable geometry for roll control.

I am thinking of an internally braced Tensegrity wing structure for a thick tapered Ultra Light wing design. Thinking of a single spar 2" OD x .065 wall Al extrusion cut into sections roughly 3' + 3' + 8' with 2' center section and an inverted W planform with hang glider like cover. This would make a nice folding package for transport and storage.

Would you be copying the RV 4 wing in the report or adding further modifications.

 

[J.L. Frusha]

I would like to see doodles of the wing proposals.

IMHO - On of the advantages of the Tensegrity wing structure is the ability to eliminate ailerons and use the cable geometry for roll control.

I am thinking of an internally braced Tensegrity wing structure for a thick tapered Ultra Light wing design. Thinking of a single spar 2" OD x .065 wall Al extrusion cut into sections roughly 3' + 3' + 8' with 2' center section and an inverted W planform with hang glider like cover. This would make a nice folding package for transport and storage.

Would you be copying the RV 4 wing in the report or adding further modifications.

I have other papers, as well. I'm actually considering something with a different Tensegrity layout.

While there are Tensegrity wing designs that can morph, the wing design I have in mind has Junkers-Flaps style control surfaces as well as Leading Edge Slats.

 

[nestofdragons]

Not quite a complete AiRecliner plan, but it's getting there...View attachment 120595

View attachment 120594

why place the pilot so high? If you let the pilot sink a lot and install the rudder the same distance higher, you will still have the needed prop clearance, a much lower CG (better for landings) and your wings will fit under the other wings in the hangar.

 

[J.L. Frusha]

why place the pilot so high? If you let the pilot sink a lot and install the rudder the same distance higher, you will still have the needed prop clearance, a much lower CG (better for landings) and your wings will fit under the other wings in the hangar.

I'm still tinkering with it, but this is the basic design layout. May eliminate the brace behind the seat, or change it some.

 

[bhooper360]

I am thinking of a spar cut into sections.

You want your aluminum wing spar cut into three folding sections, is like saying you want your battleship to transforms into a chupacabras and a Chia Pet.

I would like to use Al extrusion.

at the exact moment the last miter saw cut concluded, the American Society of Snobby Architectural Peoples will have one gaint heart attack.

This would make a nice folding package for transport and storage.

Also, the package will neatly fold into a giant spear in-flight, propelling you directly into the ground.

Have you thought about using composite materials instead. A nice balanced layup. You can place your fishing lines to promote the torsional roll control, in the meantime your wing may theoretically sustain such antics long enough to kiss your children good-night.