RE: Keith Laumer  
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RE: Keith Laumer - 12/9/2007 9:33:30 PM   
g-rock



Posts: 140
Joined: 9/21/2004
From: Newport News, VA, USA
Status: offline 		Hi,

I finally got around to building and flying a Laumer design, the Push-up. The first flight was today, needs some changes. I did not like the short motor run of the Park 250 on a 2S 720 ma Lipo. I have had longer runs on a CD-ROM motor and a 2S 340 ma Lipo (6 oz model). I think that I will try a larger prop before I change motors. It also needs some down and right thrust.

Model weights 5.6 oz, Blue Bird 303 servos, and a Castle 4 channel Berg. As you can see, I made some changes to the design, some for aesthetics, some for structure, and some for ease of building.

That is my oldest son Mike that is holding and flying the model.

Gene

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       Post #: 176

RE: Keith Laumer - 12/10/2007 4:33:04 PM   
David Ingham


 

Posts: 166
Joined: 8/22/2007
From: , CA, USA
Status: offline 		I see you have added diagonals, instead of depending on the stressed skin covering to triangulate the structure. And used three spars instead of the planking. Looks like you access the electrics through the bottom as I do.

(in reply to g-rock)
       Post #: 177

RE: Keith Laumer - 12/10/2007 5:21:19 PM   
g-rock



Posts: 140
Joined: 9/21/2004
From: Newport News, VA, USA
Status: offline 		David,

I made the center section of the wing flat instead of adding pads and used a conventional opening under the wing. Granted, the access to the electronics is narrow but I was able to then mount everything inside. I don't like to remove the wing just to turn on the "switch" so the bottom of the fuselage has two small 5/16" holes for plugging in the battery.

I forgot to add that the covering is Microlite and the transparent yellow is the most difficult covering I have ever used. It is extremely tacky and likes to curl up upon itself, if this happens, you better off starting over with a new piece. I use masking tape to prevent the curling and cut it to shape with very little overlap before applying. It is also very hard to trim for it easily tares. One good thing, it doesn't need to be pulled to remove any wrinkles for it shrinks very well.

Gene

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(in reply to David Ingham)
       Post #: 178

RE: Keith Laumer - 12/14/2007 5:08:20 AM   
David Ingham


 

Posts: 166
Joined: 8/22/2007
From: , CA, USA
Status: offline 		I flew my Push Up again. For the first time it finished the tank of fuel, but, being a complete newcomer to RC, I couldn't keep it pointed up wind and it took me two hours to find it. It did recover from a spiral dive or spin when I let go of the controls.
I am thinking I may paint the underside of the left wing tip red and the underside of the right wing tip green, like the lights on airplanes and boats. That might make it easier to see which way it is pointed.

(in reply to g-rock)
       Post #: 179

RE: Keith Laumer - 12/14/2007 7:32:03 AM   
g-rock



Posts: 140
Joined: 9/21/2004
From: Newport News, VA, USA
Status: offline 		Hi,

Push-up update: The larger prop, 8-4 increased the slow speed performance and adding right and down thrust made a big difference in the power on & off trim required. The stall speed was a little high with the 2S 720 ma battery.

The short run mentioned earlier of the Park 250 of three minutes was a bench run at full throttle. To lower the stall speed, I changed to the 2S 340 ma LiPo. We flew it yesterday and had a flight of over 10 minutes using the 2S 340 ma battery. Using the lighter battery allowed the CG to shift aft to about 30% which improved the glide and the lighter light weight of about 5 oz even, lowered the stall speed.

The model at slow speed now appears like a sport rubber powered in flight and can be flown with rudder only ,and, be kept between 10 and 30 feet of the 'deck' for minutes effortlessly. I am very pleased with it's performance now. Thanks to all who post in "1/2A" & "1/8" airplanes for some of these changes I learned from you.

Gene

(in reply to David Ingham)
       Post #: 180

RE: Keith Laumer - 12/14/2007 3:08:18 PM   
buzzard bait


 

Posts: 1018
Joined: 1/1/2003
From: Ithaca, NY, USA
Status: offline 		David, when I was teaching myself RC (with an 049 powered TF Schoolmaster, rudder and throttle only) I did not get comfortable with wind until I realized that I only got into trouble when I turned downwind. So learned to make 'S' turns ONLY into the wind, like the slope soarers do, and it completely solved the problem. You just keep winding your way toward the wind, and the wind keeps pushing it back into range. It means you don't suddenly go hurtling downwind and you never have to beat your way back upwind with the orientation problem working against you. In fact, it allowed me to get enough experience in wind that I could eventually deviate from it and still stay out of trouble. It's a real confidence booster, knowing that you can handle it.

I think contrasting colors are worthwhile, but the truth is I have never found I could rely on visual cues. The only way to stay oriented is to trust that you know what you last did, so you know what the plane must be doing, no matter what it appears to be doing. But still, I agree with what you said about painting wing tips. Just don't expect it to really solve the problem.

Jim

(in reply to g-rock)
       Post #: 181

RE: Keith Laumer - 12/14/2007 4:24:51 PM   
fritzke


 

Posts: 852
Joined: 1/3/2002
From: Saint Paul, MN, USA
Status: offline 		Gene,

My Dad has been converting a few of his planes to electric, and has found the same thing, lots
and lots of down & some right thrust required to keep the power on/off trims anywhere in the ballpark.

Nice looking Laumer plane there Gene, glad you got it flying to your liking.

I wish I had taken my one day opportunity to fly the G-Wing, but today here in
Minnesota its -2 F (that's -18c to the rest of you worldwide..). It may be a while now!

Dave


(in reply to g-rock)
       Post #: 182

RE: Keith Laumer - 12/14/2007 6:03:08 PM   
g-rock



Posts: 140
Joined: 9/21/2004
From: Newport News, VA, USA
Status: offline 		Dave Fritzke,

As you know, I grew up in Wisconsin. It's turning cold here, 52°F, tisk-tisk. On a more serious note, thanks for the complement. Over the years, I have turned into more of a builder than a flyer. That keeps my building skills up but I make a lousy pilot.

The way it flies now reminds me of my dad's rubber powered models and I wish he were here to enjoy. If you open the throttle, it becomes quite fast, quite a speed range and good penetration.

I guess that I will have to build another Laumer design someday.

Gene

(in reply to fritzke)
       Post #: 183

RE: Keith Laumer - 12/14/2007 9:14:01 PM   
Tee Bee


 

Posts: 661
Joined: 2/22/2007
From: Angleton, TX, USA
Status: offline 		That's a beautiful little airplane. Fantastic job. I wonder how it would fly with an .010.

_____________________________

Tee Bee

(in reply to g-rock)
       Post #: 184

RE: Keith Laumer - 12/14/2007 9:35:08 PM   
g-rock



Posts: 140
Joined: 9/21/2004
From: Newport News, VA, USA
Status: offline 		Tee Bee,
Thanks for the kind words. I don't know how well it would do with a TD .010 but it would be light enough. It would be a bomb with a TD .020. I don't think either could match the slow speed handeling of an electric if throttled do to prop wash.
Gene

(in reply to Tee Bee)
       Post #: 185

RE: Keith Laumer - 12/15/2007 7:36:42 AM   
David Ingham


 

Posts: 166
Joined: 8/22/2007
From: , CA, USA
Status: offline 		Thanks buzzard. Since diving into the pavement, I have mostly just gotten weeds stuck in the engine. I think I now have an airplane and a flying field that allow practicing, so hopefully is is going to be mostly flying now. Starting to watch the weather. Need to fly in the morning when there is less wind.
I mostly didn't intend to turn down wind, the airplane did that. I kept trying to steer upwind, but was not able to keep up.

(in reply to buzzard bait)
       Post #: 186

RE: Keith Laumer - 12/17/2007 4:42:03 AM   
David Ingham


 

Posts: 166
Joined: 8/22/2007
From: , CA, USA
Status: offline 		As I describes in the 1/2 A trainer thread, I lost my Push/UP. No complaints about the design. A trainer has to be easily blown by the wind. Otherwise it would be too fast or unstable. Unlike the Wright Flier, an 020 trainer doesn't need to fly always up wind to survive crashes, so dynamic stability is more important than resisting wind. The poor glide ratio (due to construction or design?) helped in this situation, but not enough.

(in reply to David Ingham)
       Post #: 187

RE: Keith Laumer - 12/18/2007 11:16:17 PM   
David Ingham


 

Posts: 166
Joined: 8/22/2007
From: , CA, USA
Status: offline
quote:

ORIGINAL: g-rock

David,

I made the center section of the wing flat instead of adding pads and used a conventional opening under the wing.

I think your wing joints wouldn't work well with Ambroid or similar solvent glue that we used in Keith Laumer's day. I assume you used CA or epoxy.

(in reply to g-rock)
       Post #: 188

RE: Keith Laumer - 12/21/2007 6:47:05 PM   
gatordad


 

Posts: 14
Joined: 12/21/2007
From: Spring Hill, FL, USA
Status: offline 		where does everybody get there laumer blueprints from new to forum

(in reply to David Ingham)