If you need assistance, please send an email to forum at 4hv dot org. To ensure your email is not marked as spam, please include the phrase "4hv help" in the subject line. You can also find assistance via IRC, at irc.shadowworld.net, room #hvcomm.
Support 4hv.org!
Donate:
4hv.org is hosted on a dedicated server. Unfortunately, this server costs and we rely on the help of site members to keep 4hv.org running. Please consider donating. We will place your name on the thanks list and you'll be helping to keep 4hv.org alive and free for everyone. Members whose names appear in red bold have donated recently. Green bold denotes those who have recently donated to keep the server carbon neutral.
Special Thanks To:
Aaron Holmes
Aaron Wheeler
Adam Horden
Alan Scrimgeour
Andre
Andrew Haynes
Anonymous000
asabase
Austin Weil
barney
Barry
Bert Hickman
Bill Kukowski
Blitzorn
Brandon Paradelas
Bruce Bowling
BubeeMike
Byong Park
Cesiumsponge
Chris F.
Chris Hooper
Corey Worthington
Derek Woodroffe
Dalus
Dan Strother
Daniel Davis
Daniel Uhrenholt
datasheetarchive
Dave Billington
Dave Marshall
David F.
Dennis Rogers
drelectrix
Dr. John Gudenas
Dr. Spark
E.TexasTesla
eastvoltresearch
Eirik Taylor
Erik Dyakov
Erlend^SE
Finn Hammer
Firebug24k
GalliumMan
Gary Peterson
George Slade
GhostNull
Gordon Mcknight
Graham Armitage
Grant
GreySoul
Henry H
IamSmooth
In memory of Leo Powning
Jacob Cash
James Howells
James Pawson
Jeff Greenfield
Jeff Thomas
Jesse Frost
Jim Mitchell
jlr134
Joe Mastroianni
John Forcina
John Oberg
John Willcutt
Jon Newcomb
klugesmith
Leslie Wright
Lutz Hoffman
Mads Barnkob
Martin King
Mats Karlsson
Matt Gibson
Matthew Guidry
mbd
Michael D'Angelo
Mikkel
mileswaldron
mister_rf
Neil Foster
Nick de Smith
Nick Soroka
nicklenorp
Nik
Norman Stanley
Patrick Coleman
Paul Brodie
Paul Jordan
Paul Montgomery
Ped
Peter Krogen
Peter Terren
PhilGood
Richard Feldman
Robert Bush
Royce Bailey
Scott Fusare
Scott Newman
smiffy
Stella
Steven Busic
Steve Conner
Steve Jones
Steve Ward
Sulaiman
Thomas Coyle
Thomas A. Wallace
Thomas W
Timo
Torch
Ulf Jonsson
vasil
Vaxian
vladi mazzilli
wastehl
Weston
William Kim
William N.
William Stehl
Wesley Venis
The aforementioned have contributed financially to the continuing triumph of 4hv.org. They are deserving of my most heartfelt thanks.
Registered Member #3414
Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245
Patrick wrote ...
Im study your work Andy, and appreaciate it. im getting ready to get s-faced here shortly, sa the pre-requiste 2015 arrival.
I've had a look at Andy's work too Patrick, and from what I can gather, he's assuming a much higher disc loading than we've discussed. At least, that's my impression.
I suggest we consider how much CF we need for hover, then add extra for max thrust, say twice the hover figure, then add a safety margin, so we're looking at, say, three times the CF needed for forces at hover.
Maybe we need more than this, but it sounds about right for a 'starting figure'.
We'll be celebrating here too in a couple of hours.
Registered Member #4266
Joined: Fri Dec 16 2011, 03:15AM
Location:
Posts: 874
Happy new year. The top view can be adjusted, at present a value of 3.1 is the front force with .11 the back force or drag, instead of 20,20, 20,10 can be used which would make it smaller, the data is based on no torque adjust might and only 1 degree eff out of 90, still trying to work out the overall eff. The data is assuming that drag has the opposite but equal force as lift,. My design just has more sodility, any way I need to do some mediation on the matter, latter
Registered Member #3414
Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245
Even if it's thicker near the hub and thinner at the tip, the lowest drag figures will be obtained using just enough uni-directional carbon to give the strength we calculate is required.
Using more carbon than is actually required just increases drag and rotating mass.
We can adjust the angle of attack to give the required Cl from the tip to as close to the hub as possible, without Cd becoming too high.
Registered Member #2431
Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639
Uni-carbon...
This carbon i layed up is 1k carbon, medium modulus, unidirectional. i can put these together and tailor the thickness in 0.004" layers. The cross pattern is an ultra-thin nylon mesh to keep it in all parrallel while wet.
Registered Member #3414
Joined: Sun Nov 14 2010, 05:05PM
Location: UK
Posts: 4245
Patrick wrote ...
Uni-carbon...
This carbon i layed up is 1k carbon, medium modulus, unidirectional. i can put these together and tailor the thickness in 0.004" layers. The cross pattern is an ultra-thin nylon mesh to keep it in all parrallel while wet.
Whether or not we want an external layer of cloth I'm not sure, but if we do, I assume it's best to wrap it around from the back of the blade, so there is a smooth layer over the leading edge.
We do need to do some maths here to determine how much carbon we need, and hence the CSA. (VABS may be useful here, if we have access to a 64 bit machine, or we could work it out the 'old fashioned' way, but I will need to revise the 'forces in a beam' thing and look up the strength of the particular CF we are using.)
XFOIL uses the chord length and profile, so adjusting chord length determines CSA for any NACA profile. (we will need a bit of maths as well, but for any NACA profile, the CSA is a function of chord length)
This site is powered by e107, which is released under the GNU GPL License. All work on this site, except where otherwise noted, is licensed under a Creative Commons Attribution-ShareAlike 2.5 License. By submitting any information to this site, you agree that anything submitted will be so licensed. Please read our Disclaimer and Policies page for information on your rights and responsibilities regarding this site.
Propeller Physics and VABs Program.
