HobbyKing.com New Products Flash Sale
Reply
Thread Tools
This thread is privately moderated by jackerbes, who may elect to delete unwanted replies.
Old Oct 09, 2011, 05:07 PM
Dreamer
Canada, ON, Toronto
Joined Sep 2008
39 Posts
Hi guys, Just wanted to share my KF wing scratch build, build thread;

http://www.rcgroups.com/forums/showthread.php?t=1518620

Im at 6.06 oz/sq.ft wing loading right now, thinking of adding more weight by adding larger batteries, and seeing how well it flies.

I know KF4 handles speed very well, but i'm more interested in having low stall speeds as well. The plan is to add a data telemetry system to get real time amp draw Information to see how different step configurations effect the performance..

currently i'm just trying to get a platform for myself. This design flies pretty well for now. After adding a few more grams, lets see how the performance is.

what im interested in knowing is whats the highest wing loading and the related flying speed.
sketchillus is offline Find More Posts by sketchillus
Reply With Quote
Sign up now
to remove ads between posts
Old Oct 10, 2011, 10:37 AM
AMA 353531
rdeis's Avatar
United States, CO, Colorado Springs
Joined Aug 2003
6,564 Posts
Quote:
Originally Posted by davereap View Post
small wire center joiners on a large wing wont be of much use, they will bend at the center
Depends on what you mean by "small"

A single 7/32 wire is plenty strong as the center joiner for a 6ft (2m) wing so long as the tube that recieves it is strongly tied in to the spar. Since you're powered rather than launching with a 100lb winch load, you could use something smaller.

Regular airfoils prefer something approximating an ellipse for dihedral, so a small angle in the center with larger angles in the tip panels generally does better than either single-break V or a 2-break flat center with tips only. I don't know if that applies to Kf airfoils as well, but it would be easy to test by using a bent wire vs straight wire.
rdeis is offline Find More Posts by rdeis
Reply With Quote
Old Oct 10, 2011, 05:24 PM
High Altitude Flyer
viking60's Avatar
Fairplay, South Park, CO
Joined Sep 2005
1,608 Posts
Another test platform design

Friends,

Here's a brief look at one of my latest experiments with the 59-1/2" MH32/KF3P wing. I'm mounting it on a E-power fuselage I have (which also is presently equipped with large 'tundra tires') After some test flying, a FFF paneled EPP Monoblock foamie fuselage will likely be built out next, allowing for a substantially lighter total flying weight, and flying with a lighter weight power system.

I just switched this wing from a single servo aileron setup to a dual servo setup. Now I'll be able to use flaperon or spoileron functions, fine-tune aileron travel differential, and experiment with quick airfoil camber adjustments.

For those interested in this wing build and it's performance on the DANCER series glider fuselages, the details are available in the DANCER discussion thread:

http://www.rcgroups.com/forums/showthread.php?t=860461

(Update: the wing performs very well on the old PT Electric fuselage, and the flaperon deployment works well for slowing it down for landings in a smaller space. I'm going to move directly to building a new lighter foamie fuselage with a lighter motor & battery- there's just too much unnecessary weight in the old classic fuselage & 05 Cobalt brushed motor. The big wheels are fun to fly for a change, doing takeoffs & landings on lightly groomed terrain.)

VIKING
viking60 is offline Find More Posts by viking60
Last edited by viking60; Oct 11, 2011 at 09:51 AM.
Reply With Quote
Old Oct 10, 2011, 07:08 PM
Onward through the fog.
Cybernaught's Avatar
Bohol Philippines
Joined Aug 2008
1,566 Posts
Paper Airplanes.

When I was a kid I spent hours folding and flying. This picture is one of many I remember from about 1955. Seems a natural RET - Vee-Tail for my junky white foam.
This is what happens when someone posts a link to the Old-Timer threads and the Nostalgia kicks in on a rainy day in Paradise.


Steve.
Cybernaught is offline Find More Posts by Cybernaught
Reply With Quote
Old Oct 10, 2011, 08:30 PM
Registered User
Dickeroo's Avatar
Joined Dec 2006
1,209 Posts
Steve...

There certainly is some magic about taking a piece of two-dimensional paper and folding it into a paper airplane that will fly like a bird. There's also a strong connection between you and it because it was you who gave it life. That's why scratchbuilt foamies are so great. You envisioned something in your imagination and bring it into the world. I still remember some of the wonderful flights that I had a long time ago. I launched some of my planes from the 24th floor of a building overlooking the New York Public Library and Bryant Park. It was on 42nd Street. What fun.

Dick
Dickeroo is online now Find More Posts by Dickeroo
Reply With Quote
Old Oct 10, 2011, 10:12 PM
Registered User
Dickeroo's Avatar
Joined Dec 2006
1,209 Posts
8 foot KFm4 Flying Wing.

The designer and builder of this flying wing is preparing a 20 footer to take to the air in the near future. Thought you might enjoy seeing this 8 pounder do its thing in the air...

Big 8 foot foam flying wing rc delta nurflugel KFm airfoil (1 min 36 sec)
Dickeroo is online now Find More Posts by Dickeroo
Last edited by Dickeroo; Oct 10, 2011 at 10:18 PM.
Reply With Quote
Old Oct 11, 2011, 09:18 PM
Dreamer
Canada, ON, Toronto
Joined Sep 2008
39 Posts
sp far i've learnt that KF airfoils are:
  • easy to make
  • produces the needed lift
  • gentle stall
  • able to handle various flight envelops

what is the Downside of using KF airfoils??

and what are your thoughts on this KF2 data,

http://www.worldofkrauss.com/foils/1815

im redesigning my platform for the Unmanned Systems Canada UAV competition, maybe it will be the only UAV there with a KF, that will give us some wow factor :P
sketchillus is offline Find More Posts by sketchillus
Reply With Quote
Old Oct 12, 2011, 12:35 AM
In the 20' glider range
anti-gravity's Avatar
Boise, Idaho
Joined Jul 2009
4,503 Posts
Quote:
Originally Posted by Dickeroo View Post
The designer and builder of this flying wing is preparing a 20 footer to take to the air in the near future. Thought you might enjoy seeing this 8 pounder do its thing in the air...

http://www.youtube.com/watch?v=OMXKoYSY_kY
B-E-A-UTIFLE!!!!!

I admire this guy and cant wait to see the finished product. Does he have a build thread,dick?
anti-gravity is offline Find More Posts by anti-gravity
Reply With Quote
Old Oct 12, 2011, 01:38 AM
Onward through the fog.
Cybernaught's Avatar
Bohol Philippines
Joined Aug 2008
1,566 Posts
Quote:
Originally Posted by sketchillus View Post
what is the Downside of using KF airfoils??
The only negative I've encountered in almost 4 years of flying nothing but KF airfoils is the insistence by some "Schmexperts" that the airfoil is bogus and doesn't work.
BTW the "Birdhouse roof" you see in the back right is my Vee-Tail building jig, the angle of the roof sides is a clean 110 degrees.


Edit:
Did a bit more work and lowered the tail into the foam wing a bit, think it looks better this way. I put in 2 deg down and 4 right when installing motor mount. Now I have to wait for paint to dry before finishing the airframe. It's a super simple build, but will it fly?


Steve.

"Pigs do fly when given sufficient thrust."
Cybernaught is offline Find More Posts by Cybernaught
Last edited by Cybernaught; Oct 12, 2011 at 06:23 AM.
Reply With Quote
Old Oct 12, 2011, 03:33 AM
Registered User
davereap's Avatar
Ashford. Kent. England
Joined Feb 2005
7,018 Posts
Quote:
Originally Posted by sketchillus View Post
sp far i've learnt that KF airfoils are:
  • easy to make
  • produces the needed lift
  • gentle stall
  • able to handle various flight envelops

what is the Downside of using KF airfoils??

:P
Where the KF is not the answer....or where the KF hasnt been sorted
High performance models..ie. the supership gliders.. racers
Indoor light weights.. ie. F3P..where the additional layer will add too much in weight

For my models which go from 10oz up and spans between 20" to 72" the KF is working very well..
They work so well that I now KF every foamie model

Ref. your question on wing loading, heavy weight and speed, take a look at http://www.youtube.com/user/rcFoamFighters who make their models heavy , using various methods..they then add plenty of power and their models go fast..
Their methods suit how they like to fly, fast.. while most of our builds being of lower wing loadings will fly slower..

Steve... looks good to me.. that will work..
davereap is offline Find More Posts by davereap
Last edited by davereap; Oct 12, 2011 at 03:46 AM.
Reply With Quote
Old Oct 12, 2011, 10:06 AM
fix-it-up chappie
tolladay's Avatar
Valley Village, CA
Joined Jan 2002
2,262 Posts
Quote:
Originally Posted by sketchillus View Post
sp far i've learnt that KF airfoils are:
  • easy to make
  • produces the needed lift
  • gentle stall
  • able to handle various flight envelops

what is the Downside of using KF airfoils??

and what are your thoughts on this KF2 data,

http://www.worldofkrauss.com/foils/1815

im redesigning my platform for the Unmanned Systems Canada UAV competition, maybe it will be the only UAV there with a KF, that will give us some wow factor :P
From what I understand, a KF tends to trade efficiency for stability. So you get more drag, but better self-righting characteristics. Mind you, this is a gross simplification, but it will do for just a bunch of guys sitting around the field.

Not every plane is designed to just fly around. Some are serious competition machines where every bit of "ommph" makes a critical difference. For these types of planes (sailplanes, racers, and indoor fliers) a KF is not well suited.

So if your plane flies on the prop, or if it can handle a bit more thrust in exchange for an easier flight, then the KF is for you.
tolladay is offline Find More Posts by tolladay
Reply With Quote
Old Oct 12, 2011, 12:35 PM
Grumpy old git.. Who me?
JetPlaneFlyer's Avatar
Aberdeen
Joined Mar 2006
12,123 Posts
KF fans,

After being castigated for expressing opinion on KF airfoils without ever having flown one I'm thinking about giving one a try My thought was a good test mule might me my 'Elf' discus launch glider. It's got the advantage of being quite small with a simple 'V' dihedral wing with no ailerons, so a pretty easy KF build I'd guess. If I do built the KF wing some back to back testing against the stopwatch between the standard Drela AG series airfoil wing and the KF would be pretty easy. The wing is removable and can be changed in seconds. The standard wing is 1m span and 180mm root chord. Airfoil is 10mm thick at the root. In true KF/foamy tradition I want to keep the build simple and quick, so intricate 'built up' structures are out, simple foam laminate or folded construction is in.

So within these constraints what's the recommended 'state of the art' KF airfoil that should represent best performance available on a discus glider? And as I'm not a foam builder what material will I need (3mm Depron?). I've got plenty of carbon and balsa for stiffening.

Looking forward to all constructive suggestions.

Steve
JetPlaneFlyer is offline Find More Posts by JetPlaneFlyer
Reply With Quote
Old Oct 12, 2011, 01:18 PM
High Altitude Flyer
viking60's Avatar
Fairplay, South Park, CO
Joined Sep 2005
1,608 Posts
Beware of trolls

Beware Of Trolls
Do Not Feed Them
viking60 is offline Find More Posts by viking60
Reply With Quote
Old Oct 12, 2011, 02:02 PM
Jack
USA, ME, Ellsworth
Joined May 2008
17,218 Posts
I constructively suggest that you study the davereap A-Clone and W-Clone (as in Alula and Weasel) builds a little. Two guys named davereap and viking60 are arguably our most deeply immersed and knowledgeable people on small gliders, slope gliders, thinner and low drag wings, and stuff like that.

The easiest way to find info the threads they have started is to click on the "show all threads startee by.." link from their blog pages. At least, that is the way at least some of us KF knuckle draggers do it, I'm sure the Clark Y community probably has a better way to find threads here.

Jack
jackerbes is offline Find More Posts by jackerbes
Reply With Quote
Old Oct 12, 2011, 02:18 PM
Reap the wild wind
headlessagain's Avatar
Bristol,UK
Joined Feb 2007
4,283 Posts
Steve
I would suggest that either Viking or Dave Reap will be able to suggest the best approach to your build as both have made a number of KFm glider wings in the past
Andy
Whoops, Jack beat me to it!
headlessagain is offline Find More Posts by headlessagain
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Idea 40" Depron Dynamite, Kline fogleman Depron build dougmontgomery Hand Launch 639 Oct 29, 2014 06:31 PM
Cool Here is my KFm-5 DLG GLider (Kline-Fogleman) dougmontgomery Foamies (Scratchbuilt) 151 Apr 21, 2014 10:08 AM
Discussion ** Kline-Fogleman Airfoiled Flying Wing ** Tony65x55 Foamies (Scratchbuilt) 3945 Apr 08, 2014 11:40 AM
Video Kline Fogleman Airfoil on a flying wing Tony65x55 Electric Plane Talk 3 Jan 30, 2009 08:37 PM
Discussion Kline-Fogleman Airfoil on a flying wing Tony65x55 Modeling Science 1 Aug 20, 2006 12:14 PM