New idea in ducted fans

Hi,Tommo,I think you may be wrong with your by-pass ratio, also i have considable experience in model and full size gas turbines.My idear for this ducted fan is from a RR high by-pass fan in an effort to reduce some of the reverse thrust in the fan design. A good   read on this subject is the book THE JET ENGINE by ROLLS ROYCE .Regards Ken Jack

hey Ken Jack

how are things going, any progress ?

if you need help on sketching some of your concepts, your welcome to PM me - id love to help out.

Troels / Denmark


Edited by Blind Vision - 17/Mar/2010 at 10:47am

Originally posted by Ken jack ......He tested inlet vanes in his fan unit and found that the breathing capcity  increased at low speed condition while not affecting high speed flight ...

Dear Ken jack,Hi
Very interesting idea, that is why I want to say something, may be well know but I want to express my own opinion.
First of all the EDF strucrure below that you explaned above is right one to increase the presure of liquid even if it is air.You will not incraese the speed. As you know , high Preasure Hydo pumps such as 24 and more bars has multi stage weels, but they are driven in one axis and by one motor.
#################
                                      V1   #####
                                              N1         #####
                                                           N2           ##########
                                                                           N3
                    
--------->                                                                                        --------->
 
                        
                                                                           ##########
                                                          #####
                                           #####
################

Second, you are right when telling that blades at stages shall become smaller in diameter and in the pitch.
This is general structure of air jet turbines compressors.

Now my suggestion and vision, may be a bit crazy but suggestion : ) try to insert between the ducts the "bee mesh"  structure ( about 5-10mm wide)  to get laminar air flow in front of every sucking entrance of ducts and avoid air cyclone at inlets.As far as you are using multi motors system and not able to sincronize the blades steps you are getting the  air cyclone between ducts and that is why second and next stages motors getting more RPMs. Air cyclone creates the vaccumm effect at the ducts inlet.

B.Regards

Truly,

Robert, Armenia

Ha Kenjack This is finetune. I thought up a way that maybe all things could be ballanced quickly. You need 6" of carbon fiber tube with OD that will fit the ID of what ever you are balancing. Then you will need round stirafoam corks or something very light that will fit the od of the carbon fiber tube. Like a saucer shape. Then you slip the prop or impellar to the center of the carbon fiber tube and lock it. Then put the flotation on the ends. Then just drop it in some water. Make sure there are no bubbles that will upset the ballancing. It should bring the heavy side of the prop/impellar to the bottom. I havent tried this yet but will soon. Finetuned50s.   ROY

Hi ,Roy,Thanks for sharing your thoughts with us as this is what this thread is about.I have a very complex balancer i built some time back to balance gas turbine rotors and have since found it to work better on ducted fan rotors as they have a lower resonance speed which makes it   a lot more accurate balance .most of my fans run very smoothly.I was going to make my balencer as a project on this site but felt it would be too complicated even whith help being offered by Mark D . Regards Ken Jack