Archive for the ‘ configuration layout ’ Category

Will it blend?

Seems like, yes it did ūüôā

Created with the latest iRhino alpha.

Changes:
* Placeholder engine nacelles added.
* Rudder added

I was reading today the book “Fluid dynamic drag” a bit and got kind of inspired: canopies and wind shield discontinuity contributes very much to the drag coefficient of the fuselage. Not only the laminar nose seems important, but all kinds of places where something ends and something else continues are sources of waste of engery.

So if the plane is completely faired with no discontinuity of any kind, theoretically the drag coefficient should be very low.
In this picture, the engine nacelle placeholders are just placeholders, because they are not yet accurate airfoil, and it has not been taken into account that in Rotax engines the propeller shaft is not in the middle of the engine, but almost on the top of the engine, this creates a fairing that has the lower side turned up a bit and is therefore not completely symmetrical.

The engine nacelles may need to be moved outwards, otherwise there is not enough clearance between the fuselage and the propeller arc.

I was also reading one day some NASA tech paper about wing tip mounted propellers. I have not drawn such things to this picture, but I may add it later – small brushless DC motor on each wing tip lowers the induced drag quite a bit according to the tech paper (although on high aspect ratio wing the effect is not that radical as on with a low aspect ratio wing that would otherwise be poor).

Potential issues for placing engine nacelles on wings (which seems pretty necessary for a twin, after all, may be the least bad compromise) and blending are the followings:
* the wings take a lot room to build (because they are very long)
* making the mold is difficult, because it has to be done from CNC cut pieces and glued together
* moving the center section to airport or transporting it in a container may be challenging, because if the area up to engine nacelles is continuous part of the center section and not separatable, it means that this is basically wider than the width of the container, shipping the plane to another continent might be a challenge (it seems that it would need to be flown like the design point has been set)

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Will it blend?

Seems like, yes it did ūüôā

Created with the latest iRhino alpha.

Changes:
* Placeholder engine nacelles added.
* Rudder added

I was reading today the book “Fluid dynamic drag” a bit and got kind of inspired: canopies and wind shield discontinuity contributes very much to the drag coefficient of the fuselage. Not only the laminar nose seems important, but all kinds of places where something ends and something else continues are sources of waste of engery.

So if the plane is completely faired with no discontinuity of any kind, theoretically the drag coefficient should be very low.
In this picture, the engine nacelle placeholders are just placeholders, because they are not yet accurate airfoil, and it has not been taken into account that in Rotax engines the propeller shaft is not in the middle of the engine, but almost on the top of the engine, this creates a fairing that has the lower side turned up a bit and is therefore not completely symmetrical.

The engine nacelles may need to be moved outwards, otherwise there is not enough clearance between the fuselage and the propeller arc.

I was also reading one day some NASA tech paper about wing tip mounted propellers. I have not drawn such things to this picture, but I may add it later – small brushless DC motor on each wing tip lowers the induced drag quite a bit according to the tech paper (although on high aspect ratio wing the effect is not that radical as on with a low aspect ratio wing that would otherwise be poor).

Potential issues for placing engine nacelles on wings (which seems pretty necessary for a twin, after all, may be the least bad compromise) and blending are the followings:
* the wings take a lot room to build (because they are very long)
* making the mold is difficult, because it has to be done from CNC cut pieces and glued together
* moving the center section to airport or transporting it in a container may be challenging, because if the area up to engine nacelles is continuous part of the center section and not separatable, it means that this is basically wider than the width of the container, shipping the plane to another continent might be a challenge (it seems that it would need to be flown like the design point has been set)

Trying out different configuration layout for the twin concept


I decided to post here a snapshot of one of my Rhino-models. It has now struts which hold the engines out of the wing surface. The canopy was also replaced with windows.

Trying out different configuration layout for the twin concept


I decided to post here a snapshot of one of my Rhino-models. It has now struts which hold the engines out of the wing surface. The canopy was also replaced with windows.

Illustration for the previously mentioned idea

Here is a rough illustration about the configuration layout. This picture is not drawn into any scale dimensions, it is just “artistic” illustration of the idea. I did not draw taper to wings etc. because I wanted to draw it quickly. Here is the picture:

The drawing program is by the way the Rhino3D for MacOSX, a pre-beta -version of it, I am privileged to be a beta-tester.

Basic locations I had in mind:
Seats are in front of the canard wing. The fuel and baggage is stored between the canard and main wing. The engine nacelles are more forward than in the Long-Ez derivatives. They protrude from the main wing forward in a similar manner like they would be additional fuselages in midwing configuration. The engine nacelles are not necessarily fat enough to look realistic, but they hopefully deliver the basic idea, as this is not a final drawing but a computerized sketch of the configuration layout. The two horizontal stabilizers are in the propeller stream because that way they are more effective than winglet mounted rudders would be on a canard aircraft, and instead of becoming effective at relatively high speed, these can be made to be effective from almost zero speed, similarly than conventionally configured aircraft.

The idea is influenced by this:
http://www.scaled.com/projects/proteus_specifications.pdf

Illustration for the previously mentioned idea

Here is a rough illustration about the configuration layout. This picture is not drawn into any scale dimensions, it is just “artistic” illustration of the idea. I did not draw taper to wings etc. because I wanted to draw it quickly. Here is the picture:

The drawing program is by the way the Rhino3D for MacOSX, a pre-beta -version of it, I am privileged to be a beta-tester.

Basic locations I had in mind:
Seats are in front of the canard wing. The fuel and baggage is stored between the canard and main wing. The engine nacelles are more forward than in the Long-Ez derivatives. They protrude from the main wing forward in a similar manner like they would be additional fuselages in midwing configuration. The engine nacelles are not necessarily fat enough to look realistic, but they hopefully deliver the basic idea, as this is not a final drawing but a computerized sketch of the configuration layout. The two horizontal stabilizers are in the propeller stream because that way they are more effective than winglet mounted rudders would be on a canard aircraft, and instead of becoming effective at relatively high speed, these can be made to be effective from almost zero speed, similarly than conventionally configured aircraft.

The idea is influenced by this:
http://www.scaled.com/projects/proteus_specifications.pdf