RE: Four Star 60 Build...The Saga Begins  
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RE: Four Star 60 Build...The Saga Be... - 8/15/2005 1:31:16 PM   
bruce88123


 

Posts: 10715
Joined: 11/26/2004
From: Memphis, TN, USA
Status: online 		Congrats on the flights and a kit well built.

Now it's your turn to help others. Explain what your error was in measuring the CG. This may help someone avoid the same mistake in the future.

Any idea what would have happened to your plane if your friends had not found that error? New kit or major repairs most likely and a lot of disbelief on your part. If you had gone out Sunday and tried to fly alone, you would have had a wild handful on your hands. Just glad it got caught.

Bruce

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RE: Four Star 60 Build...The Saga Be... - 8/15/2005 1:47:45 PM   
MountaineerFan36


 

Posts: 300
Joined: 3/1/2005
From: Akron, OH, USA
Status: offline 		Not sure where my mistake was on measuring the CG. I was suspicious that I was able to get it to balance with no adjustments. The only difference is that I measured and checked my CG with the plane upside down with the arms of the cg machine on the main spar right next to the fuse. At the field, two guys stood on either side of the plane with it upright and lifted it off the ground at the main spar. Not sure if this would make a difference or not.

I had put together sort of a checklist of things that I wanted the guys at the field to look at before I flew it, and CG was on that list. I also had them check out all the control surface throws, help me set up high and low rates for the control surfaces, fine tune in the engine etc. But yeah, I'm really glad that we caught the CG problem before I flew it.

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RE: Four Star 60 Build...The Saga B... - 8/15/2005 2:03:31 PM   
NJAIRSTRIKE


 

Posts: 451
Joined: 1/22/2005
From: , NJ, USA
Status: offline 		MountaineerFan36, You have done a great job! Congrats on a succesfull maiden!

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RE: Four Star 60 Build...The Saga B... - 8/15/2005 2:16:49 PM   
Paladin049


 

Posts: 97
Joined: 7/5/2005
From: Austin, TX, USA
Status: offline 		Mountaineer, congrats on a job well done and a beautiful bird! Glad to hear those first flights went so well. BTW...I've always had someone else first flight my birds (all ARFs to this point). Had much greater confidence in taking her up myself once one of the Old Guard checked it out for me!

Enjoy the fruits of your labor...and post some video soon for all your fans!!

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RE: Four Star 60 Build...The Saga B... - 8/15/2005 3:02:29 PM   
RCKen



Posts: 15128
Joined: 7/10/2002
From: Lawton, OK, USA
Status: online 		Mountaineer,
Here's what I do when I balance. I mark the CG as per the plans and mark that spot with a sharpie. I then use the CG machine to balance the plane. I do one thing a little different than most people, I completely assemble the plane and balance it BEFORE I cover the plane. I do this so I won't have to cut covering later down the road if I have to add weight. Of course I do a final CG check once the plane is completely covered and ready to fly.

Ken

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RE: Four Star 60 Build...The Saga B... - 8/15/2005 3:17:26 PM   
bubbagates



Posts: 8162
Joined: 5/30/2004
From: Elizabethtown, PA, USA
Status: offline 		The only thing I'm wondering about is the need for 12oz's. That seems like allot. The Saito will handle it and on a 4* it will not make that big of a difference, but if he is able to remove half of that then if he thinks it floats now, 6oz's will make a difference.

I use an OS91 Surpass on mine and needed no weight at all by stuffing a 4 cell 2700mah Expert batt up under the tank that weighs in at roughly 6oz

Here are the engine weight's

Saito 100

Engine (Only) Weight: 19.5 oz
Muffler Weight: 1.4 oz

OS91 Surpass without the pump

Weight-With Muffler: 24.2oz

So all total I have roughly a 3.5 oz heavier engine in mine and probably a 2 oz difference in battery although I'm not sure of what battery he is using

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RE: Four Star 60 Build...The Saga B... - 8/15/2005 7:49:21 PM   
raideron



Posts: 1692
Joined: 1/12/2004
From: Fort Mohave, AZ, USA
Status: offline 		Same here on my ARF... with a Mag 91... I started with the Battery under
the tank, now it's under/behind the wing bolts.. No weights added

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RE: Four Star 60 Build...The Saga B... - 8/15/2005 8:49:58 PM   
MountaineerFan36


 

Posts: 300
Joined: 3/1/2005
From: Akron, OH, USA
Status: offline 		I have the battery up against the first former right behind the tank. I'll try sliding it under the tank to balance before I permanently add any weight.

Remember I added a second set of tri stock braces on the underside of the horizontal stabilizer/fuse, and I used a small amount of epoxy to secure them. This may have contributed to it being tail heavy.

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RE: Four Star 60 Build...The Saga B... - 8/15/2005 9:15:59 PM   
bruce88123


 

Posts: 10715
Joined: 11/26/2004
From: Memphis, TN, USA
Status: online
quote:

ORIGINAL: MountaineerFan36

Remember I added a second set of tri stock braces on the underside of the horizontal stabilizer/fuse, and I used a small amount of epoxy to secure them. This may have contributed to it being tail heavy.


Naturally it added a little to the condition but not 12 ounces or anywhere close. Move the battery and try again.

Did the instructions say to balance upright or inverted? Or did they just give a balance point and leave it for you to determine the method?

< Message edited by bruce88123 -- 8/15/2005 9:17:20 PM >

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RE: Four Star 60 Build...The Saga B... - 8/16/2005 1:34:36 AM   
bubbagates



Posts: 8162
Joined: 5/30/2004
From: Elizabethtown, PA, USA
Status: offline 		The 4* series all get balance inverted. According to SIG, the plane has a roughly 2:1 CG moment meaning that 1 ounce at the tail needs two ounces at the nose.

After watching your build and the fact the saito is lighter than my engine I could see 6 ounces but 12 ounces makes me curious. There is nothing wrong with that much but if you can get it lighter it should would not hurt at all

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RE: Four Star 60 Build...The Saga B... - 8/16/2005 3:20:22 AM   
MountaineerFan36


 

Posts: 300
Joined: 3/1/2005
From: Akron, OH, USA
Status: offline 		Bubba:

You got me curious to about the 12 oz. and here is what I found out.

It is indeed 6 oz. and not 12. The lead weights are the sticky type that come in a strip and say "prather" across the top. I have 6 "segments" of this strip on the nose, hence 6 oz. For some reason, I thought each section of the strip was 2 oz. not 1.

One of the guys at the field noticed that I did have some room on the engine mount to move it forward a bit if I wanted to....so I guess that is an option.

I think most likely I'll try moving the battery pack under the fuel tank as far as I can get it (it is a 4 cell NiCD 800 MAH pack BTW) Then check to see how much weight I need to add.

Once I determine the appropriate weight, I was thinking about where I could mount it. I really want to keep it out of the engine compartment, so I thought I might sheet the weight with some balsa, then glue/screw it to the underside of the compartment and then cover it so that it blends in to the fuse. You guys know of any better options than this?

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RE: Four Star 60 Build...The Saga B... - 8/16/2005 3:42:47 AM   
bubbagates



Posts: 8162
Joined: 5/30/2004
From: Elizabethtown, PA, USA
Status: offline 		Joe,

That's allot better. I thought 12oz's seemed a little much based on how well this thing was built

Do not move a thing unless you really want to try. 6oz would be just about right based on the engine differences and battery differences so I'd leave it alone.

You can try to stuff the battery under the tank and you may only save an ounce maybe two, which on that plane will make no difference it how it flies. 6oz's would but not one ounce. Moving the engine will require you redo your throttle linkage and based on the issues you had with it I would not even consider it.

The old adage comes to mind here. If it a broke don't fix it.

To be honest with you, I would glue them to the top of the little piece of the fuselage on the inside just in front of the firewall right under the engine, right where you have your drain hose coming from the saito or out near the end of the cheeks on the inside. You could always paint them black and they will never show.



< Message edited by bubbagates -- 8/16/2005 3:51:02 AM >

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RE: Four Star 60 Build...The Saga B... - 8/16/2005 5:41:45 PM   
R T W



Posts: 152
Joined: 8/28/2003
From: Edemonton, AB, CANADA
Status: offline 		Thanks for the great thread I just found it last night. Lots of great tips to help the newbie. I have just started to build a Pete'n' Poke and know that the information in this thread will be of great assistance. Congrats on the maiden flight and many more flights.


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RE: Four Star 60 Build...The Saga B... - 8/16/2005 6:03:31 PM   
bruce88123


 

Posts: 10715
Joined: 11/26/2004
From: Memphis, TN, USA
Status: online 		You read all this in just one night? That deserves a medal in it's own right.

If you took an average of 15 seconds per post it would have taken 3 hours to read the entire thread, not counting time waiting for your computer to update.

< Message edited by bruce88123 -- 8/16/2005 6:06:31 PM >

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RE: Four Star 60 Build...The Saga B... - 8/16/2005 6:28:47 PM