Re: Weight and Balance - help with choosing additional nose ballast - or not


KEN4ZZ
 

Hi Marc-

Just a suggestion: If your flight testing w/ the reduced ballast goes well, consider using something useful as ballast. Lead certainly is compact, but if you've got the space a well stocked tool kit including a small sledge hammer for tie down stakes and a selection of spares that could save the day on a trip (cowl screws, nuts, bolts, screw clamps,oil, tires, inner tubes, etc.) might be nice to have along someday.?? Also, again depending on space available, an otherwise unnecessarily large battery (automotive sealed AGM for instance) or a back up battery - both largely lead anyway - could act as ballast that has usefulness beyond its mass.

Ken

On 7/19/2019 2:39 PM, 'Marcus Borom' borommarc@... [canard-aviators] wrote:
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Thanks to Marc (at least he spells his name the same way as mine). Keith and Jay for responding.??

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This is a great support group.

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Based on the advice I have received, I am considering testing the aircraft with a reduction in the current nose ballast of 24.7 lbs to 10.7 lbs., instead of adding 10 to 25 lbs of additional ballast.??

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My nose ballast is currently divided into two castings of 10.7 and 12.7 lbs.?? Removal of the 10.7 lb ballast will be a simple task..

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I am attaching a revised spreadsheet showing the changes in the CG for various loadings.?? I also show the CG position for a full load of fuel with no occupants.?? The nose will be very light.?? If there are any warning signs here, I would appreciate an alert.

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Note to Jay;?? My 2004 A/C weight was 1021.0 lbs and the weight in 2019 is 1030.9.?? My adjusted nose ballast will bring them together again.

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BTW.?? The 15 hours I mentioned was between weighings.?? I have been flying my bird for 33 years ??? one crash at Oshkosh (1988 ??? see http://marc-borom.com for details) and one mid-air collision (2017 ??? the other guy was at fault).?? I am now a member of UFO (Union of Flying Octogenarians).?? Looks like I am going to have to install ADS-B In/Out for 2020.

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Thanks again,

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Marc Borom??

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From: canard-aviators@...
Sent: Friday, July 19, 2019 3:18 AM
To: canard-aviators@...
Subject: Re: [c-a] Weight and Balance - help with choosing additional nose ballast - or not

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Marcus,

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How much did the basic weight change after 15 years? More a curiosity, as where I work we redo WB after any major maintenance and often times at time intervals as well. It???s was a bit shocking the first time you realize an aircraft can pick up several hundred pounds in dirt and grime over 24 months in all the nooks and crannies.??

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Thanks

Jay B


On Jul 18, 2019, at 11:50 PM, marc_zeitlin@... [canard-aviators] <canard-aviators@...> wrote:

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Marcus Borom wrote:??

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Question. ??Do I want to favor the nose ballast that places the CG in the first flight box?


Keith Spreuer wrote:
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My opinion is that it is best to fly at the aft limit as much as possible. That of course is assuming you did thorough after CG testing to be sure you have a deep stall margin.

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I agree 100% with Keith here. And I'll expand on this a bit.

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First, I don't quite understand whether the 23.4 lb. of ballast is already included in the calcs you show or not, but as long as YOU know whether it's part of the CG calcs, that's all that matters.

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Now, for EZ type aircraft that are not considerably overpowered (VE's with O-320's, Berkuts with O-540's, etc.) for the original design of the airfoil combination, you almost always want to operate at the aftmost CG in the acceptable range, as this will minimize trim drag, lower takeoff and landing speeds, and maximize cruise speed, while still protecting from deep stall and pitch instability.

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Whether you have an O-235 or O-320 Long-EZ, you will want to operate it at the rearmost CG position of 103" (NOT 104" - the rear limit was changed in the CP's at some point). This assumes, as Keith wrote, that you have TESTED the airplane to that CG position for stability and stall, per the Phase I requirements.

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You should ballast the plane (either with or without the existing 23.4 lb, or part of it) so that with YOU in the front seat and full fuel (fuel's at 104", so full fuel will be the rearmost CG as fuel burns) you're right on the 103" limit. Anyone/anything in the rear seat, at 103", will NOT move the CG aft of that.

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My $0.02.

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--??

Marc J. Zeitlin?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ????marc_zeitlin@...

?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ????http://www.cozybuilders.org/

Copyright???? 2019?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ??Burnside Aerospace





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