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Old Sep 11, 2005, 12:53 PM
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80SGliderDude's Avatar
W. Santa Cruz, CA
Joined Jun 2005
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Nose lead in Mach Dart?

How much lead are people using to balance their Mach Dart's? I'm up to almost 7 ounces in the nose!!! Is this normal? Seems a bit much.

Thanks in advanced.

-80SGD (chad)
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Old Sep 11, 2005, 12:59 PM
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timmig's Avatar
Southern California
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It's taking 5oz for mine--FYI
Timmig
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Old Sep 11, 2005, 01:04 PM
It pays to be a winner
Keith R.'s Avatar
T-Town, AZ
Joined Jun 2004
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I guess i should buy a whole lot of lead for my MD once they ship it... I guess they are "out of boxes". About how much ballest are you guys adding for when you fly at places such as fermin?

Keith
(who is patiently waiting)
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Old Sep 11, 2005, 01:05 PM
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80SGliderDude's Avatar
W. Santa Cruz, CA
Joined Jun 2005
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Quote:
Originally Posted by timmig
It's taking 5oz for mine--FYI
Timmig
Thanks Timmig. 6.5 oz gets me around 3" from the leading edge. I'm wondering if this is good enough considering the CG's others are using are near 3".
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Old Sep 11, 2005, 01:38 PM
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screamin' eagle's Avatar
Pacific Palisades, CA
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7 ozs sounds like a lot to me too. I don't remember the measurement of the CG location, just that mine was at the rear of the main spar. Guy I sold it to flies it 1/8 or so behind that...
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Old Sep 11, 2005, 05:31 PM
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80SGliderDude's Avatar
W. Santa Cruz, CA
Joined Jun 2005
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Maybe I'll put 6 ozs in and see how she flies. As I was about to melt some lead, I found an old diving weight belt next to the BBQ that had tiny lead pellets inside each weight bag. Filled up a baggy with some of the shot and shoved it into the nose of the Dart in front of the battery. The shot conformed really well to the inside of the nose. Now I can go fly it! If I need to remove some, I'll just pour a little out at a time. Once I like how she flies, I'll secure inplace with some epoxy. Much easier than casting lead, IMHO. I even bought a cast iron skillet. DOH!

Off to Davenport... looks like the wind is >20 mph.
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Old Sep 11, 2005, 06:22 PM
It's not a Toomah.
cwayland's Avatar
Orange County California
Joined Apr 2005
388 Posts
Balloons work really well for that. Only problem is apparently after time the rubber of the balloon degrades and they can burst, spreading pellets all over the inside of your plane and possibly causing a crash.

Just measured mine, 3 and 7/16" behind the leading edge along the side of the fuse. Some people tell you on the back of the spar, 1/4" behind it etc.. Ive found that the mach dart wasnt built to the most exacting specifications, and people's spars seem to be in slightly different locations? Dont know if this is true or what is happening, but you cant go wrong measuring behind the LE.
That cg is probably 1/8" behind where I usually fly, I just did a repair on the fuz behind the wing and have not had a chance to re ballance it. It ds'd a little better with a 1/4oz or so more in the nose. It bangs turns real nice now but is a little more squirly on the back side. I think I will have two balloons, a front side one and a back side one. Hope this helps.

clint
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Old Sep 11, 2005, 07:17 PM
Detail Freak
target's Avatar
Harbor City, CA
Joined Oct 2003
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Quote:
Originally Posted by 80SGliderDude
Maybe I'll put 6 ozs in and see how she flies. As I was about to melt some lead, I found an old diving weight belt next to the BBQ that had tiny lead pellets inside each weight bag. Filled up a baggy with some of the shot and shoved it into the nose of the Dart in front of the battery. The shot conformed really well to the inside of the nose. Now I can go fly it! If I need to remove some, I'll just pour a little out at a time. Once I like how she flies, I'll secure inplace with some epoxy. Much easier than casting lead, IMHO. I even bought a cast iron skillet. DOH!

Off to Davenport... looks like the wind is >20 mph.
When you mix the lead with epoxy, don't forget to take into account the weight of the epoxy, or you'll possibly end up with a nose-heavy plane....
It's easier to add lead than to remove it when mixed with epoxy in the nose of the plane...

T
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Old Sep 11, 2005, 08:43 PM
It pays to be a winner
Keith R.'s Avatar
T-Town, AZ
Joined Jun 2004
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Quote:
Originally Posted by target
When you mix the lead with epoxy, don't forget to take into account the weight of the epoxy, or you'll possibly end up with a nose-heavy plane....
It's easier to add lead than to remove it when mixed with epoxy in the nose of the plane...

T
Never thought of that target. I guess that is why you are a "thinker"

Keith
(who is always re-inventing the wheel)
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Old Sep 11, 2005, 10:58 PM
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80SGliderDude's Avatar
W. Santa Cruz, CA
Joined Jun 2005
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Thanks everyone for your input. The main spar is a bit close to the trailing edge than what I've seen in other's pictures. There was not much room for the servos unless I Dremel out the spar (which I didn't). Another thing about the kit: the wing saddle needs a bit of sanding at the very front so that the wing sits flush on the saddle.

Well... the Mach Dart flew perfectly today and was a very successful maiden flight. Winds were smoking >20 or so. I was a bit nervous about tossing it out. Once I did, it flew hands off. Not one click of anything. I had some nice turns to check things out. Then turned off my dual rates for full controls . Did some rolls (not very impressive but lots of potential in the right hands). Got up some speed and did some nice loops. Speed runs were really cool. After a second flight, I poured out about 1.5 ozs of shot. Probably could pour out more. Wow what a difference. Landings were very, very fast. The Dart did not want settle down even inches above the ground (it was like a lawn mower). Spoilerons and flaperons didn't do anything. I ended up snaping the nylon wing bolt near the TE on a fast landing approach on my 4th flight. I'm probably going to cut flaps, however I think I will need to get rid of my Flash5 radio (man I just bought it too!). I'm going for the gold and will get a Royal Evo9

To sum it all up, the Mach Dart rocks!

-80SGD (chad)
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Old Sep 11, 2005, 11:20 PM
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Southern California
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Cool--- looks like you'll end up with about the same weight in the nose. You'll LOVE the Evo-- but only if you take the time to learn the programming-- it's VERY different from all of the Asian built radios--but WILL do much more.
Have fun
Timmig
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Old Sep 12, 2005, 12:25 AM
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screamin' eagle's Avatar
Pacific Palisades, CA
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Quote:
Originally Posted by 80SGliderDude
The main spar is a bit close to the trailing edge than what I've seen in other's pictures. There was not much room for the servos unless I Dremel out the spar (which I didn't).
-80SGD (chad)
Wow, that's really weird. Mine had tons of room in the wing for the servos. They could have put the spar an inch further back and there's still be room (although they wouldn't have fit flush anymore). I wonder if the spars are getting moved around??? Seems unlikely.
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Old Sep 12, 2005, 01:04 AM
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80SGliderDude's Avatar
W. Santa Cruz, CA
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Quote:
Originally Posted by screamin' eagle
Wow, that's really weird. Mine had tons of room in the wing for the servos. They could have put the spar an inch further back and there's still be room (although they wouldn't have fit flush anymore). I wonder if the spars are getting moved around??? Seems unlikely.
I looked at BillL's build thread and then at mine and was shocked at the placemnet of the main spar. Mine is about 72 mm from the LE if you measure where the servo bay is. I had about half the size hole Dremeled out before I hit the spar. The HS-81MG barely fit. I just bought this sailplane two weeks ago so it would be interesting to hear if others are seeing the same thing.

-Chad
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Old Sep 12, 2005, 01:11 AM
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The version I had used to be Timmig's. I bought it last December, and I think Tim had it for a while too. Weird.
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Old Sep 12, 2005, 01:19 AM
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Yeah, I'm pretty sure that the spars don't get palced very accurately. Seems that people with identical handling all have the CG at different points in relation to the spar. I, too, hit the spar on the way back with the hole. It starts about 1/2" forward of the "lip" for the covers.

--Alex

--Alex
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