Design and build an 'Ultralight'

[Student Pilot]

Just go up 4 posts; the 3 view drawing is there; it's fully enclosed so you can't see the internal tube frame but basically the same setup as the HM-1000

But not a flying flea design; it's a boxwing.

So basically a side by side Ligeti Stratus?

 

 

[Blackhawk]

No, it's a side by side boxwing design, but not a Ligeti Stratus.

 

 

[spacesailor]

Just another  "woe be me"

 

It's not just weight that get you, It's that

 

BUREAUCRATIC

 

Wing load Rule.

 

spacesailor

 

 

[Blackhawk]

Oh, Yeh !

 

 

[kasper]

Just another  "woe be me"

It's not just weight that get you, It's that

 

BUREAUCRATIC

 

Wing load Rule.

 

spacesailor

Nope.  If you are 95.55 you are not wing load measured but stall speed restricted.  And if it’s 2 seats and RAAus ultralight it’s got to be 95.55. 

 

 

[spacesailor]

Stall speed restricted, Is it a different Stall speed to 95-10, ?.

 

spacesailor

 

 

 

[M61A1]

Nope.  If you are 95.55 you are not wing load measured but stall speed restricted.  And if it’s 2 seats and RAAus ultralight it’s got to be 95.55. 

Go outside......find a good solid brick wall....bang your head against it repeatedly. Same result.

 

 

[Thruster88]

This is my concept mid boom propeller aircraft; a bit heavier the yours at 600kg MTOW and the boom has more support from below.

It should have very good handling characteristics and light on fuel. 

 

Unfortunately no folding wings.

 

[ATTACH]38911[/ATTACH]

Hi Blackhawk,, interesting design it will look good. Have you calculated the CG and centre of lift ? It looks nose heavy to me. 

 

 

[rotax618]

Sorry, I should read the posts more thoroughly before commenting. Your design has merit, I have not studied the aerodynamics of box wing types, but I believe they have structural and aerodynamic advantages and there have been some successful examples. I built a Flying Flea many years ago to understand their supposed advantages, unfortunately I did not enjoy flying it, the delay in yaw/roll couple was very uncomfortable. Others find them acceptable.

 

I don’t know how far you are in the design but I suppose a large scale RC model will give you the CG and a fair idea of any vices before you commit to any structural analysis.

 

I look forward to hearing of your progress.

 

 

[Blackhawk]

Only a concept.

 

 

[Deskpilot]

BK, now that's a beautiful design. I once had the wish to build a Sunny Box-wing but found that the original safe design had been taken over by a new developer and had been made unsafe(according to the original designer). I think you should seriously consider building your plane as IMO, it's a winner.  

 

IF you were to decide to add contra-rotating props, how would you do it? Just asking.

 

 

[Blackhawk]

There are a lot of difference way's to produce a coaxial propeller drive

 

This sketch could be one

 

Or you could use one of these

 

https://www.youtube.com/results?search_query=Drive+for+coaxial+propellers+1+-+10

 

Just work on what suits your application best; but I would use belts to the prop shafts.

 

 

 

[kasper]

Stall speed restricted, Is it a different Stall speed to 95-10, ?.

spacesailor

 

[ATTACH]38930[/ATTACH]

Yes

 

95.10 has NO stall speed restriction. It is NOT defined by stall speed at all.  It is wing area limited. 

 

95.55 IS stall speed restricted. It give not a damn about how you achieve that stall speed just that you claim to meet the stall speed required.  If you use 15m^2 of wing without flaps or 9m^2 with really complex flaps does not matter so long as the stall is low enough. 

 

End of. Can’t be clearer. The two registration series are measured for compliance in completely different ways.