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RE: Pusher AP plane build thread - 11/28/2005 1:48:59 AM   
W4UAV



Posts: 423
Joined: 1/23/2003
From: Gainesville, FL, USA
Status: offline 		I did get off on a tangent there, lets keep it to the build! Dan, would you recommend maybe a pitts muffler and moving the engine a little above the thrustline? Get the head into the air rushing over the wing and cool. If he used the standard pitts muffler and mounted the engine upright the pitts' pipes would be out to the left side of the plane, they are usually too long so the builder can cut them down to fit near a cowl setup.
Mike R.

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RE: Pusher AP plane build thread - 11/28/2005 2:24:55 AM   
kd7ost


 

Posts: 402
Joined: 10/12/2003
From: Nampa, ID,
Status: offline 		I don't know. I mounted my engine inverted to keep the firewall small while getting the prop shaft as high up as I could. I don't have the engine cowled in at all. I think there is more than enough airflow to run this way. The engine isn't in the prop wash but at an idle on the ground and getting run up for take off gets the plane in motion. A tightly cowled engine in a tractor configuration is at greater risk. I think it will be OK that way. It will also allow the carb to stay lower down the firewall so it's closer to the fuel pickup level in the tank. One can always put an engine mount with longer rails on to push the engine and muffler farther away from the fire wall for clearance. If Skycam41 has adequate prop clearance for his known runways it may not be an issue. I've seen a lot of planes with props close to the ground that aren't set up in these twin tail boom pushers like ours. It's common to see grass stains and nicks from rocks on the props so I don't want to sound too paranoid about the clearance. Low wing tail draggers bust props commonly on bad landings. I think I just got jumpy because I was flying off gravel with Zinger 18 inch wooden pusher props. A rock in the right place and I was out a 25.00 prop just like that. That 2 cid gas Fuji I’m using really vacuums loose debris on a take off run. It moves one heckuva lot of air.

I don’t see any reason he wouldn’t want to shift the thrust line upward above the aircraft centerline. Randall1959 does that to great extent by putting the motors and engines on his planes up high on pylons etc. I don’t like to move too far away like that just because of induced drag in that style. I’m not suggesting that’s a bad thing mind you. In a slow flying stable AP plane that’s a manageable quality. My application just works better with faster flight and more efficient travel through air. I conserve fuel that way too.

Dan

(in reply to W4UAV)
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RE: Pusher AP plane build thread - 11/28/2005 2:34:13 AM   
randall1959



Posts: 863
Joined: 8/29/2004
From: Bolckow, MO, USA
Status: offline 		My glow AP plane is nearly overpowered so that's mainly how I get away with it. I also stretched the wing out on both ends for more lift. Drag is not a critical issue on a big floater plane and will also help it fly more slowly in some cases.
My plane weighs 9 lb fully loaded, but with a 72" wing it lands at little more than walking speed, even in light breezes. I've dead sticked it a couple of times to see how it glides and even being as heavy as it was, it still glided for quite a long time and came in nice and slow.
My glow ap plane actually flies a lot like it did when it was a simple trainer. The ground handling was a bit tricky until I figured out that my configuration needs "up" thrust instead of down.
If Skycam were to elevate his motor, on a pusher it would also need some "up" thrust so as to not want to push the nose over under power.
Right now I'm happy with my glow plane so now my attention is focused on building a couple of good electric ap planes. Much more people friendly and easier to transport.
But for shots out in the country it will most definately be the slimer. Say what ya want, but a slimer stays in the air longer, less power issues, and will allow you much more in lifting power.

< Message edited by randall1959 -- 11/28/2005 2:37:31 AM >

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RE: Pusher AP plane build thread - 11/28/2005 2:55:55 AM   
kd7ost


 

Posts: 402
Joined: 10/12/2003
From: Nampa, ID,
Status: offline 		Agreed Randall1959. And I want to emphasize I wasn't talking down the Engine on a pylon. It's the best way to go in many cases. There are even pusher planes with single tail booms that have the pusher engine up on a pylon for clearance. In this particular build though, the design criteria is different. I also agree with your assessment about electric and fuel burning planes. I can take my gasser out in the early morning and although I have to land once an hour for gasoline, I can fly all day long without having to charge anything. But, I'm building an electric now to fill in some gaps and fly in different settings.

Dan

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RE: Pusher AP plane build thread - 11/28/2005 5:42:44 AM   
Skycam41



Posts: 516
Joined: 9/8/2003
From: Fort Macleod, AB, CANADA
Status: offline 		Here is a picture of the enigne being held in place. My personal feeling is that it will be OK but that is just my thought, not based on fact...lol. I am leaning towards an upright muffler as they are called so that the exhaust stack comes off the side of the engine and points straight down which would be very nice for helping to keep the slime off the plane and would not be a big chunk of metal in the air stream. As always, I am open to suggestions and opinions



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RE: Pusher AP plane build thread - 11/28/2005 5:49:32 AM   
kd7ost


 

Posts: 402
Joined: 10/12/2003
From: Nampa, ID,
Status: offline 		Boy that's a good looking engine. I think your idea sounds good.

Dan

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RE: Pusher AP plane build thread - 11/28/2005 6:12:53 AM   
Skycam41



Posts: 516
Joined: 9/8/2003
From: Fort Macleod, AB, CANADA
Status: offline 		Thanks Dan, I too really l ike the powder coating on the Irvine, looks "smart." Well it's turn in time for this chap...g'nite all.

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RE: Pusher AP plane build thread - 12/1/2005 7:31:35 PM   
Skycam41



Posts: 516
Joined: 9/8/2003
From: Fort Macleod, AB, CANADA
Status: offline 		Looks like I have the muffler problem solved. Bisson mufflers up here in the frozen white north are goign to custom make an upright style muffler which will bolt right onto the motor and have the exhaust stack pointing down. I am still waiting for the wing kit to arrive Seeing as I still have the old plans for an LT40 wing I will figure out the boom mounting and get to work on that.

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RE: Pusher AP plane build thread - 12/2/2005 12:10:47 AM   
W4UAV



Posts: 423
Joined: 1/23/2003
From: Gainesville, FL, USA
Status: offline 		Mike, they also make spacers to extend the muffler from the engine, you might try one of these if it appears the muffler is going to be too close to where you want it, and they usually come with longer bolts. I saw one at the LHS today.
Heres the one I saw, to give you an idea of what I mean, gotta find one for your engine specs:
http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXD638&P=0

Just a tip!

Mike R.

< Message edited by W4UAV -- 12/2/2005 12:11:49 AM >

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RE: Pusher AP plane build thread - 12/2/2005 12:15:25 AM   
Skycam41



Posts: 516
Joined: 9/8/2003
From: Fort Macleod, AB, CANADA
Status: offline 		Thanks Mike...I sent the same pic I posted to BCM and he was going to make the header long enough to clear the mount but I may still want to use a spacer. I like the idea of the muffler pointing straight down...less crap getting on the plane

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RE: Pusher AP plane build thread - 12/2/2005 2:31:05 AM   
1967ghia


 

Posts: 15
Joined: 11/28/2005
From: Garden Grove, CA, USA
Status: offline 		wow that's nice, looks like some work...


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RE: Pusher AP plane build thread - 12/2/2005 6:33:44 AM   
randall1959



Posts: 863
Joined: 8/29/2004
From: Bolckow, MO, USA
Status: offline 		I know you weren't talking down on the pylon idea. I was just expanding on the why and how of it all. I too, have built two different electrics for those times when the glow plane is hindered due to space and safety concerns.
There is a lot of drag in my setup but I've also found that drag will work for you if you do some careful planning. When I first set up my glow ap plane it had a stock wing and was much much too fast to be practical. That's when I hit upon the idea of extending the wing (more drag and more lift) and adding wingtip droops.
That's the great thing about this hobby is that there are so very many ways to skin the proverbial cat.

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RE: Pusher AP plane build thread - 12/3/2005 4:15:45 PM   
Skycam41



Posts: 516
Joined: 9/8/2003
From: Fort Macleod, AB, CANADA
Status: offline 		OK gang....thinking caps on all. Method of mounting the camera is the subject. The two requirements are A) Being able to tilt the camera through a small range and B) Elliminating as much vibration as possible. Open for suggestions, drawings etc.....

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