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Old Aug 20, 2010, 06:08 PM
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USA, CA, San Carlos
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Here's the updated 20 incher tiled. It's really 20 inches now

- Jeff
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Old Aug 21, 2010, 02:08 AM
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OOPS! Those plans I posted are actually about 18". I had Sketchup set to perspective instead of parallel projection. I have updated 20" plans I will post as soon as I get back on the right computer.

- Jeff
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Old Sep 13, 2010, 09:09 AM
Curiouser and curiouser
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Rochester, NY, USA
Joined Oct 2005
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Well I raised the thrust line 1" and it is a little less pitch sensitive.
I guess I will have to lay off the throttle or put a much smaller prop on it.
Next I will try to mix throttle with elevator and move the battery to the bottom.
If that works well, I will put a rudder on it.

Walt
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Old Oct 06, 2010, 01:55 PM
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United States, FL, Alachua
Joined Jul 2004
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My Drenalyn Maiden Flight

After too many weeks I finally got to try my Drenalyn in the air! I think this is going to be one of my favorite airplanes after I get it sorted out a little.

Here is my setup:
9mm EPP all around
Wing 22" wide by 20" deep
blue and red Wonder 1300
2s 900 Lipo in the video
10oz. all up weight. Figures out to 3.71 oz. square foot!
2 HTX900 servos
Elevons (my first) no rudder

I built it with the motor attached at the start of the wing. It was looking like I was going to need to add weight to get it to balance at the recommended CG. I really hate to add dead weight to an airplane, so I extended the nose to get the motor more forward and give me more room to adjust the battery. The first picture below shows the nose extension. I balanced it to the recommended CG with both a 2s and a 3s battery and marked the positions on the fuse so I could repeat the battery placement.

After a very short flight I thought that it was a little tail heavy so I moved the battery almost to the nose position. That seemed to make it fly much better for me. The second picture below shows a 2s battery so that the airplane balances on the recommended CG. The third picture shows the same battery where it seemed to work better for me. I also took out a bunch of reflex....I think I had too much to start. I set up dual rates, but needed to go to high rate so it would loop well.

The video shows how it flys for me. It seems to not be able to gain altitude very quickly but it may be underpowered. I also thought that the problem is that it has too much downthrust so it wants to pull the nose down. I was wondering about the downthrust as it will make a much smaller inside loop than a outside loop, would that be a symptom of irrational exuberance when setting the downthrust?

Also it wants to dive when I try to make it roll. Any suggestions on what would cause this? It is not really bad, just an annoyance to me.

I did put some washers under the motor to lessen the downthrust and give it a little more right thrust. I plan to give it another go and see if that helps.

Maybe I need to look at:
...1. More power maybe a 3s
...2. Less downthrust
...3. More right thrust
...4. CG more forward or back
...5. A better pilot (this should probably be combined with any of the above)

Please take a look at the video and give me any suggestions for improvement.

Drenalyn RC Airplane Maiden Flight (3 min 11 sec)
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Old Oct 07, 2010, 01:01 PM
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Vancouver Island, Canada
Joined Jul 2003
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It's really hard to tell from a video of any trim issues. Now if I were to actually fly it, I could tell.

With any flying wings, you need to trim so that it has a minimum amount of reflex. Try changing the CG first. Once you get it to fly straight and level at a low throttle setting, see what is does at full throttle. Then adjust the motor's angles accordingly. If it climbs, a bit more down and vise versa.

Hope this helps: Frank
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Old Oct 07, 2010, 02:14 PM
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London, UK
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How much would it cost to send a Drenalyn from Florida to Vancover Island ?
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Old Oct 07, 2010, 07:40 PM
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United States, FL, Alachua
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Thanks Goldguy! I put some washers under my motor mount to give the motor less downthrust and more right thrust. I was going to fly it today as the winds were very light, but other things got in the way.

Saturday looks like the next chance to give it a go.

I will try your suggestion on how to test for the correct amount of down thrust.

After putting up the video and watching it, the video seemed to make the Drenalyn look like it was flying pretty good. At the time it seemed to be not so good while flying it.

Thank again,
Ray

Quote:
Originally Posted by goldguy View Post
It's really hard to tell from a video of any trim issues. Now if I were to actually fly it, I could tell.

With any flying wings, you need to trim so that it has a minimum amount of reflex. Try changing the CG first. Once you get it to fly straight and level at a low throttle setting, see what is does at full throttle. Then adjust the motor's angles accordingly. If it climbs, a bit more down and vise versa.

Hope this helps: Frank
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Old Oct 07, 2010, 07:47 PM
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United States, FL, Alachua
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Quote:
Originally Posted by dekan View Post
How much would it cost to send a Drenalyn from Florida to Vancover Island ?
Sounds like it would be kind of pricey to me!

With the airplane only weighing 10 oz. the problem would be the large box. Most shippers will charge for oversize boxs. Maybe if I ran it through a leaf shredder I could just pour it into a large envelop and drop it into a mail ! I could just put "some assembly required" on the outside!

Ray
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Old Oct 07, 2010, 09:57 PM
I'm slow but I'm expensive
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United States, GA, Snellville
Joined Nov 2003
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Indoor recamendations

Hi all,
I am thinking about building a Drenalyn for indoor flying. My site is an Aviation maintenance school hanger and shop. On the order of 250" x 250" x 35"... with poles every 40 feet I am looking for recommendations as to what might be a proper size and power, P/W ratio, original or shallow camber and such. EPP, depron, fan fold?
I am looking forward the the collective wisdom of this list.
Thanks in advance,
Ken
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Old Oct 08, 2010, 03:42 AM
D'oh.. Dumb Left Thumb
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London, UK
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Quote:
Originally Posted by High Flyin' View Post
Sounds like it would be kind of pricey to me!

With the airplane only weighing 10 oz. the problem would be the large box. Most shippers will charge for oversize boxs. Maybe if I ran it through a leaf shredder I could just pour it into a large envelop and drop it into a mail ! I could just put "some assembly required" on the outside!

Ray
Nah. Just remove the wing and Fin and flat pack in a pizza box....Mind you the post office might wonder why anybody would want to send a pizza from Florida to Canada...
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Old Oct 08, 2010, 10:50 AM
flyin' fool
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Vancouver Island, Canada
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Better still, fly it up using GPS. Afteral, Manard Hill flew a model airplane across the Alantic.
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Old Oct 08, 2010, 11:01 AM
flyin' fool
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Vancouver Island, Canada
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Quote:
Originally Posted by Ken Lilja View Post
I am looking forward the the collective wisdom of this list. Ken
Wisdom???? I think you have us confused with someone else.

For indoor, built it to suit the equiptment and material you have. Weigh everything, 'guesstamate' the weight of the foam and do a bit of math. Built it big enought to get the wing loading as low as possible. Shoot for around 3 ounces per square foot on anything above 18" in span. Then, use a motor that will spin a big prop. Using your wattmeter, you do have a wattmeter don't you, a good reading is about 150 watts per pound.

Low weight and bags of thrust is what makes indoor work.......and fun.
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Old Nov 23, 2010, 09:26 PM
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United States, FL, Alachua
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After flying my Drenalyn a few more times it is turning out to be my favorite at least for fun factor. This is my first airplane with elevons and it is truly a blast to fly! And with it being made of EPP it has that nice bounce back effect. I have nosed it in a couple of times hard enough to snap the prop and it was ready for another flight after putting a new prop on it. If it were FFF it would need the glue treatment back at the studio. It will fly inverted very well! While flying today there was a little wind and it was a blast to cut the throttle back until the airplane had very little or no forward movement but would descend nicely to a landing.

Now that I am getting more confident....I am thinking maybe larger throws on the elevons. My Drenalyn has a 23" wingspan. How much throw is everyone using on their Drenalyns?

Another small problem is when flying full throttle at an even altitude,, when I give it full aileron throw it wants to dive some. Any suggestions on getting it to keep from diving during a roll?

Thanks all.....everyone should build one of these!
Ray

Ray
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Old Nov 24, 2010, 01:55 AM
flyin' fool
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Vancouver Island, Canada
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Ray/Ray:

Try moving the battery back a bit at a time and/or add a little more down thrust to the motor. Of all the Drenalyns I've built, only one tucked in a turn/roll and the above seemed to be the cure. Also, make sure it's balanced laterally, very important.

I alway set the throw to about 45 degrees.
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Old Nov 24, 2010, 11:06 AM
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Thanks goldguy! I don't think I have 45 degrees...I will check. I will try moving the battery pack back first as I have plenty of room.

Thanks again,
Ray
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