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Old Aug 08, 2009, 08:22 AM
Lee
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USA, UT, Orem
Joined Jul 2004
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I'm anxious to see both your KF Snowball fly and the KF Assassin.. Hope you have lotsa blank tape to fill up.

Questions:
How thick is the wing at the thickest?
How did you round the leading edge?
Is that normal white bead foam?

It appears you have done a great job rounding the leading edge. The leading edge of the wing is very important to the performance of the wing. It affects the stall and lift of the wing. I used the symmetrical airfoil on my Roswell Delta and if flies very well and is very stable. I hope you have the same luck.

Part of the reason I am a fanatic on the airfoils is I used to fly glassed slopers in my past life. People would religiously refer to a plane by it's airfoil as much as by the kit. Names like SD6060 and E374 and SD7032 and SD7003 were common. I think I have jigs for about 20 different airfoils just in one sloper wing shape and I tried many of them. I would buy the SD wind tunnel data books for a little light reading.

In the wind tunnel data they would refer to the % of deviation from the perfect plotted airfoil. It's their fault I am a fanatic. There needs to be means to the madness. Look at how many airfoil variations people are calling KF airfoils. It feels like there needs to be a group of numbers to identify all the properties.

Here is a link to an airfoil data base. You can see pictures of the airfoils by clicking on the gif links.

http://www.ae.uiuc.edu/m-selig/ads/coord_database.html



.
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Old Aug 08, 2009, 05:59 PM
Lee
PERFECT LANDING !!!
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USA, UT, Orem
Joined Jul 2004
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Jeff was flying today so I asked him to do some more aggressive flying with the Assassin XL 48".

It's hard enough to keep the plane in the screen but when the pilot is going this fast and turning so hard it is nearly impossible. Here are a few clips of what I got but trust me I missed the best stunts. I even had to use the video editing software to do a zoom in here and there so you may see a little graininess in the video at times.

Assassin #10 WOT aerobatics (3 min 50 sec)


This video is of the Roswell Delta that is also called the Secret Weapon. This plane is also built for combat using many of the same building techniques used on the Assassin. I have been cutting deltas since the 80s.

Roswell #3 Combat Delta (3 min 33 sec)
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Old Aug 08, 2009, 08:08 PM
Rotozuk's Avatar
United States, CA, Novato
Joined Sep 2003
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That video was very well done.. Shows a good range of the planes performance slow and fast. Looks to be plenty stable, rolls nice, very solid.

As a side note, the new shipping method worked very well as the 7 wings arrived today, ahead of schedule! Cores look nice, only issue would be that the rubber band has compressed the foam, and it still has not recovered after several hours. Tape would be better!

Thanks, we should have several of them up and running for next weekend.

-Wayne
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Old Aug 09, 2009, 03:23 AM
Onward through the fog.
Cybernaught's Avatar
Bohol Philippines
Joined Aug 2008
1,566 Posts
Quote:
Originally Posted by Lee
I'm anxious to see both your KF Snowball fly and the KF Assassin.. Hope you have lotsa blank tape to fill up.

Questions:
How thick is the wing at the thickest?
How did you round the leading edge?
Is that normal white bead foam?

It appears you have done a great job rounding the leading edge. The leading edge of the wing is very important to the performance of the wing. It affects the stall and lift of the wing. I used the symmetrical airfoil on my Roswell Delta and if flies very well and is very stable. I hope you have the same luck.

Part of the reason I am a fanatic on the airfoils is I used to fly glassed slopers in my past life. People would religiously refer to a plane by it's airfoil as much as by the kit. Names like SD6060 and E374 and SD7032 and SD7003 were common. I think I have jigs for about 20 different airfoils just in one sloper wing shape and I tried many of them. I would buy the SD wind tunnel data books for a little light reading.

In the wind tunnel data they would refer to the % of deviation from the perfect plotted airfoil. It's their fault I am a fanatic. There needs to be means to the madness. Look at how many airfoil variations people are calling KF airfoils. It feels like there needs to be a group of numbers to identify all the properties.

Here is a link to an airfoil data base. You can see pictures of the airfoils by clicking on the gif links.

http://www.ae.uiuc.edu/m-selig/ads/coord_database.html



.
Hi Lee,

I got it finished but I'm not going to fly today. Winds still around 30 mph/ It's almost 4pm here and Edna wants me to help her a bit getting ready for our 6th anniversary party tomorrow. And they said it wouldn't last!

Now to important matters: RC stuff...

The foil thickness at the thickest point is 1.5" It could be perhaps 1/16th less but my sheets are almost an immeasurable bit below 1/2"per. With hot glue 1.5" is a good average.

I make the leading edge square and then cut the corners off with a razor knife and sand to round with a big board covered in 60 grit. I clean it up with hand sanding and a scrap of 80 or 100 grit and, for me, it's ready for tape.

This foam is white bead very light and crumbly. the beads are about 1/8" average size or a bit bigger. 22 pesos, just under 50cents for a 2'x2'x1/2" sheet. this Assassin Mod uses 1.5 sheets and about 3 large glue sticks, about 4 meters of FG and colored tape tape and one Popsicle stick for horns.

My steps are not 50%. If you remove the elevons they are 50% on the basic wing sans control surfaces. I'd estimate they are closer to 40% with the elevons included. They add add 2.5" to the chord. I have a thing about not getting the control surface hinge-line too close to the step.

My balance point for the CG is 7.5" and it's right on for 20% MAC. Weight came in at 16.2oz but the wing area is about 50% more than your standard build due to a longer chord and my wing loading is right on 5.5oz/sq ft.

Cross your fingers for me.

My interest earlier on in my early RC gliding days was to work up to F3B but with raising my two kids by myself and working a double shift there wasn't time to develop the skills. I was a bit of an airfoil nut myself. Spent lots of time going over the SD and Eppler offerings. Devoured RC articles on high tech gliders and studied things like setting up the crow position for spot landings etc. The Germans seemed to be the experts back then. It was fun but now I'm taking a much more relaxed pace with things. Still having fun and that's what counts. I'll try to provide any info I can that you may want. Just ask away.

Pics below.

I'll video when I test and will post the results good or bad. I'm not building for combat but for acrobatics and windy flying.

Take care,
Steve.

The masking tape in the picture isn't permanent. I'm out of the clear stuff at the moment and everywhere is closed on Sundays here.


Edit:
God Bless her, Grandma found me some clear tape so I replaced the masking tape with clear and it makes a bit of difference to the asthetics... See additional pictures. Also a pic of the sanding block with my tape as size reference. It's about 16"x9" or so. Makes quick work on the leading edges using the table edge as a guide. I also use it to true up the center before connecting wing halves and to square the tips.
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Old Aug 09, 2009, 06:31 PM
Onward through the fog.
Cybernaught's Avatar
Bohol Philippines
Joined Aug 2008
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Assassin Mod Maiden. (Of sorts)

Well It flew and it has great potential. Here's the video.

Assassin Maiden (0 min 41 sec)


It left my hand fine and started well but my primary worry is that I won't have control and I always set the throws to too much for a first flight. You'd think I'd learn. I mostly had it till I got the plane in the sun. Hard landing caused minor damage. It seems to be stable and seems to fly well fin-less. The plane is good but my flying leaves a lot to be desired. I think it proves the fin-less concept will work OK with with the KFm4 foil. See how well she takes off for the first 20 meters or so. when I gave just a touch of "UP" she went pretty much vertical. Plenty of powerand plenty of control. I need to detune her just a bit. Will repair and re-fly asap but first I need to check out the Snowball.

Steve.



Edit: 8/10/09 13:34:00
Repairs complete and throws adjusted but we have company for out anniversary party and I can't get to the field this afternoon. The first day without gale force winds in two weeks.

By the time I got my hand from launch to stick it was in the ground full bore. My skill level is not up to this plane's performance. I will not build another one for quite a while. way too fast for me.
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Old Aug 09, 2009, 07:35 PM
ty8
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Hope this works? Trying to post a picture of the build.
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Old Aug 10, 2009, 07:53 AM
Lee
PERFECT LANDING !!!
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USA, UT, Orem
Joined Jul 2004
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Quote:
Originally Posted by ty8
Hope this works? Trying to post a picture of the build.
I moved the picture to the photos on page #2 Looks good!!!!

Steve, Looking good. waiting for your next video to see if you can get it trimmed out.

Lee
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Old Aug 10, 2009, 01:17 PM
Lee
PERFECT LANDING !!!
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USA, UT, Orem
Joined Jul 2004
8,630 Posts
Quote:
Originally Posted by Rotozuk
That video was very well done.. Shows a good range of the planes performance slow and fast. Looks to be plenty stable, rolls nice, very solid.

As a side note, the new shipping method worked very well as the 7 wings arrived today, ahead of schedule! Cores look nice, only issue would be that the rubber band has compressed the foam, and it still has not recovered after several hours. Tape would be better!

Thanks, we should have several of them up and running for next weekend.

-Wayne
Wayne

Tape is a good idea. We will try it.

Shoot some video please....

Lee
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Old Aug 10, 2009, 05:22 PM
Onward through the fog.
Cybernaught's Avatar
Bohol Philippines
Joined Aug 2008
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Quote:
Originally Posted by Lee
I moved the picture to the photos on page #2 Looks good!!!!

Steve, Looking good. waiting for your next video to see if you can get it trimmed out.

Lee
Last attempt with the Assassin totaled it. I am thinking of using your dimensions with the KFm4 and I'll try to get it all in EPP for a more bulletproof plane. This will require bracing and will take some thinking. In the mean time I have increased the motor size on my Buzzard flying wing and set the %MAC to 25% so I'll be more ready for the speed and agility when Assassin #2 is ready.

I'll keep you posted.
Steve.
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Old Aug 10, 2009, 09:12 PM
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United States, CA, Novato
Joined Sep 2003
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Quote:
Originally Posted by Lee
Wayne

Tape is a good idea. We will try it.

Shoot some video please....

Lee

Will see if we can.. We usually are having too much fun.

We started building with what we had on hand. Luckily I have the motor and speed control, but negative on the servos. Currently have some small 9 gram servos cut in. Might buy some better servos tomorrow. Anyhow, we spent an hour or so cleaning the cores, cutting the tips, hot gluing the cores, installing spar, cutting elevons and cutting in the servos. I use a knife and a dremel to cut the bays. Quick and no evil fumes. Anyhow, we have 2 planes up to this point. Going to cut the battery box last as I want to confirm the CG location.

Oh yeah, and still need to make some motor mounts since we didn't buy the full kits. Laser cutter guy is giving me a quote on a mount I drew up last night. Hmm.. I'll attach a drawing for you in case you are interested. It has the bolt pattern for a normal can 400 motor and also the red hobby city motor. (We wanted to use them for various different planes.) The inside oval cut out should allow a little better ability to hold onto the plane in side loads.

-Wayne
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Old Aug 11, 2009, 10:50 PM
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Well thats it you got another convert...... gone from zagi to unicorn and slowstick to this now...... the zagi flew like a turd for me (probably was a lil overweight) and the altitude (6000) the unicorn was great till i cut it down for speed, the slowstick... well you just cant kill them and they fly anywhere.... but seeing you guys fly those at 12k..... blows my mind.....

question though I have read all the posts in here but there seems to be no clear "target weight" for the plane... what should i be looking to hit (yes i know light as possible)

Thanks... can't wait for the plane , and the parts (hobbyking) to get here......
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Old Aug 11, 2009, 11:25 PM
Lee
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USA, UT, Orem
Joined Jul 2004
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Quote:
Originally Posted by asjeep
Well thats it you got another convert...... gone from zagi to unicorn and slowstick to this now...... the zagi flew like a turd for me (probably was a lil overweight) and the altitude (6000) the unicorn was great till i cut it down for speed, the slowstick... well you just cant kill them and they fly anywhere.... but seeing you guys fly those at 12k..... blows my mind.....

question though I have read all the posts in here but there seems to be no clear "target weight" for the plane... what should i be looking to hit (yes i know light as possible)

Thanks... can't wait for the plane , and the parts (hobbyking) to get here......
I have built the plane under 13 oz but realisticly for combat keep it under a pound (16-17 oz) and you will be fine. Scotts plane that I think is in video #5 or so is 18.5 oz and it flies well just wants a little more speed on landing.

I had a bomb drop on one of my Assassins so I was looking for a bomb in the trash can at the flying field. I usually drop the plastic water bottles and pop cans that I find in the trash. This particular day there were no bottles or cans just an emeregency tire repair high pressure can that was at least 10 oz in weight. I jokingly put it in the bomb drop of my 36" Assassin and launched it. I must admit my plane wasn't as controllable with the can being 1/3 the wingspan but it flew and I carried the can up till the plane was a dot in the sky then I stupidly dropped the can. Obviously the can was gone off the plane by the way the plane shot into orbit, but the can was dark in color and we couldn't see it. Everyone was yelling, "heads up!!! heads up!!!" to warn everyone of the incoming misstle. It hit so hard about 30 feet from us that I still get ill just thinking of what could have happened.

Moral to the story. The plane does fly at 26 oz carrying a full sized spray can.

Lee
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Old Aug 11, 2009, 11:54 PM
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Joined Sep 2003
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Got some more work done on our planes tonight. Ended up making some simple motor mounts from some steel I had sitting in the garage. Electronics are in, programmed and working. Planes are taped, and elevons are on mine. Should be ready for test flights tomorrow. Going to test fly without color.

Mine is coming in around 13.4 ozs without color (with 3M). I have a bunch of monokote/Ultracoat, so will probably use that. Maybe sign vinyl (scraps from sign company) as it is free, but it does not hold up as well and weighs more.

-Wayne
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Old Aug 11, 2009, 11:58 PM
I HOOVER because I SUCK!
Portland,Oregon U.S.A.
Joined Sep 2007
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I am really loving the design simplicity and elegance of your plane- but I love to work in smaller scale

I would like to scale it down to fit the motor I have-

could do-
2s lipo 250mah to 800mah- probably stick to 400mah- shorter flight times but have alot of them

a fieago inrunner 12 x 32mm think around 6000kv? from #52 heli

or

a hk 10g 2200kv outrunner- this is what I want to use- not sure on prop but think start around 4 x 4?

either a basic 7a esc or my cc10

servos- think the #52 heli servo- about 5g but pretty good torque and good on 2s and 3s

or could use the 9g if I need more torque- but guessing smaller ones will be fine

my main questions are what wingspan (thinking about 20"?) and most important, is if it is say, 2/3 size of yours (24"), what is the thickness of thickest part of wing? chord?

sorry this is newer stuff to me, and really want to do about a 1/2 scale of your assasin!



mk
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