New idea:
- A body that comprises of a laminar body and wing blended together
- There is a V-tail in a blended boom
- Rear of the center section has suction slot on top side
- The boom contains a electric fan that is used for suction and additional thrust
- There are two turbocharged Rotax 912UL engines in the wings which are hidden in blended pods that continue the airfoil shape of the wing without interruption
- Both engines turn additional turbochargers which drive generators which generate electricity for the rear fan of the aircraft
Items that need to be studied:
- does pressure thrust work with this kind of shape, or does it require axisymmetric body?
- compare the drag of minimum axisymmetric body with non-blended wings to a blended wing body which has larger cross sectional area, but potentially lower wetted area.
- wing incidence relative to the center section - center section has a lower aspect ratio than the wings and what it requires to achieve optimal lift distribution in this combined case
- the achievable gain from the lack of interference drag or very small interference drag
- optimal wing loading for a combined blended wing body compared to a pod+boom+wings solution
- shark fin shape on the outer wing sections, the gain and the issues
7 comments:
I am glad you are thinking about my earlier comment about a Goldschmied body with blended wings.
Just to re-state the benefits:
Goldschnied Body: Negative drag! Sounds impossible but there is lots of research to support this claim. There are no "known" aircraft flying using this type of body, so there is no real life example.
Blended Wings: No body / wing interference drag. Look at the birds. They have blended wings!
I would be great if you could model these design ideas. I don't have the expertise to model or simulate an aircraft, otherwise I would. I have an electrical engineering degree and not a aeronautical engineering degree, so I am only an amateur in this topic.
More of a question than a comment: Original documents by Goldschmied concerning this suction technique seem to be placed in the world of airships/blimps. Does this technology tranfer seamlessly into the world of fixed wing aircrafts?
And let's not get too carried away with negative drag, I hear a distant voice whipering "perpetum mobile" ;)
Juri: We have a heatpump with 300% efficiency heating our house. Energy does not come from nowhere, but is just utilized more effectively.
I can and plan to model this with iRhino.
But it takes some time to do the model because blended wing body is harder to draw than a pod+boom+wing+tail.
One thing I am concerned about, what happens to the elliptical lift distribution when the center section is a really bad wing and has significant deviation in chord?
I got confirmation from a friend, that unlike my concern, it is the opposite. The elliptical lift distribution is better on a blended wing body than on a wing+pod+boom because the in the traditional configuration the center pod causes the lift to drop to zero. Even a different wing chord in the center section is then said to be better than the discontinuity in the wing.
Therefore blended wing body it has to be.
Then the remaining issues are:
- Pressurization of non-circular fuselage form (blended wing body)
- Goldschmied propulsion integration with BWB. It has been said to work on axisymmetric body, but does it apply to a BWB?
Answer to Juri: I have read from other sources that the airship wind tunnel model was the size of small aircraft and it was found that it was superior to small aircraft. That is why it was assumed it works on body of a small aircraft, because the wind tunnel model was same size as one a such thing :). I think it was explained in one NASA tech paper about it that I read earlier. I don't remember the link to it right now, but it is on my hard disk and I can find it with Spotlight.
I've been working on the design of a Goldschmied based aircraft too.
We did some CFD work applying Goldschmied principles to a helicopter(used the Super Lynx as the baseline for modification) and finally after accounting for some other losses and installation and all that, we found that the reduction in drag comes out to be aorund 9%.
I'm currently working on designing a fixed wing aircraft based on the Goldschmied body. As much as the BWB idea sound interesting i've been pursuing a wing-pod-tailboom design only for stability issues. Also my personal opinion is that a BWB would cause a lot of the suction slot area ot be covered (due to the nature of blending the wing and the body) thereby reducing the BL suction and hence the pressure thrust.
My only question that no one has been able to answer till now is : Why hasnt any big GA manufacturer picked up on Goldschmied till now?
A sort-of-an-answer to "why hasnt any big GA manufacturer picked up on Goldschmied till now" and many other questions alike: http://www.flyingmag.com/leftseat/1161/what-is-a-revolutionary-airplane.html
The article is focused on planes a bit bigger than what Karoliina is working on, but the same rules apply, I think...
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