Flying some different blended wing bodies (BWB) using EDF's

[L Edge]

Telnar1236 does a lot of fluid dynamics on EDF models and I take the approach of summing the forces and moments approach. Still you have to build models and test out what happens in flight to get it to be stable thru the entire flight envelope . The last segment I covered had to do with different shapes of EDF exhaust nozzles. Very interesting in the different shapes.

Last thing is to get some time in flying (BWB) to see the effects of the EDF's. Looking at 6th Gen fighters models, (blended wing bodies without rudders and 2 to 3 EDF's) seem to where it is going. Going to present lots of problems and is it possible to fly one without a gyro?

Took this model with an airfoil design(does funky stuff when flying) and stripped it to add an 64mm EDF(like Telnar's jet in the rear) to so what happens, if anything, with the airflow.

The EDF fan is 5 bladed and sits 1/2 above and 1/2 below.

Will try some runs with a short duct and then without a duct and see any differences. Also looking to see with BWB's and EDF's in rear, how does it fly and of course will it fly? Waiting for good winter weather to fly.

Next big project is to make the 6th Gen fighter invisible.

 

[LitterBug]

Next big project is to make the 6th Gen fighter invisible.

Wonder Woman appreciates your efforts to build her a new generation invisible plane!

 

[Piotrsko]

Invisible? How you fly it? Oh yeah some people have RPV.

 

[quorneng]

It could be argued that the 1960s Handley Page HP115 as a very acute delta was a sort of blended wing plane.

Build to test the slow speed characteristics of a likely super sonic design it certainly flew as does my true scale all foam EDF model.
Like the full size it does have some aerodynamic quirks, like uncontrollable high alpha wing rocking, but it did not need a gyro.

 

[Piotrsko]

Rocking is consistent with all triangle shaped wings. Somewhere I read about higher speed airflow causing it. Not high speed, just speed somewhat above stall but below cruise speed. Still does at cruise, but much less movement as to be relatively unnoticeable. Lower the nose and it reduces a bunch. Had I known it would come up one day, would have grokked the article in Scientific American much better. I did just go and decided to avoid that planform

 

[telnar1236]

Rocking is consistent with all triangle shaped wings. Somewhere I read about higher speed airflow causing it. Not high speed, just speed somewhat above stall but below cruise speed. Still does at cruise, but much less movement as to be relatively unnoticeable. Lower the nose and it reduces a bunch. Had I known it would come up one day, would have grokked the article in Scientific American much better. I did just go and decided to avoid that planform

It's mostly from transient effects with the leading edge vortex, so yeah, local variations in the speed of the flow over the wing, and you also get interaction with the lateral-directional modes

NASA paper on it:

https://ntrs.nasa.gov/api/citations/20030009800/downloads/20030009800.pdf

 

[Piotrsko]

Ooh nasa paper better than SA... and 2002. Way cool since I understood most of it. Best part conical vortices running down wing edge there you go.