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


Bob Holliston
 

Years ago at the EZ races Dave Lind (the guy who flew to ALL 50 states and had the most perfect Long EZ I've ever seen) told me that out on course he was (way) running out of pitch down trim with the stock pitch system. He said that he added 10 pounds of ballast to the nose and it got WORSE. I didn't see how this could be but that's what he said...….. or maybe I just remember it wrong. I showed him my leaf spring/actuator system and I think that's what he did. He had the fastest plane in the 320 superstock class and could average over 200 knots at any of the five courses. 


On Mon, Jul 22, 2019 at 7:16 AM 'Marcus Borom' borommarc@... [canard-aviators] <canard-aviators@...> wrote:
 

Hi Mike,

 

Thanks for your comments.

 

Regarding my snug ballast.  It is completely captured by the battery box, as you can see in the photos I posted in a previous email and again here.  I went to cast shapes to avoid what had happened to me years ago when I was just cramming Scuba weights in the space in front of the battery.  One of the weights slid out through the space under the battery tray and ended up under my feet at the rudder pedal in flight.  A bit disturbing, but since I have been using shaped castings, I have not, and will never again, experience a perambulatory ballast weight.

 

I can’t imagine that I will ever see an IAS of 160kts in Arizona.  The airport elevations here are at the normal cruising altitude for folks back on the east coast where the airports are rarely more than 300 ft above sea level.  I frequently fly into airports here with runway elevations above 5000 ft.  In AZ I carry an oxygen tank. 

 

I may try an incremental weight increase in the nose, but for now, I am going to fly with the W&B as it is.

 

Thanks for all the help.

 

Marc B

 

From: canard-aviators@...
Sent: Monday, July 22, 2019 2:22 AM
To: 'Marcus Borom' borommarc@... [canard-aviators] <canard-aviators@...>
Subject: Re: [c-a] Weight and Balance - help with choosing additional nose ballast - or not

 




Hi Marc,

Frankly, you could go with the +12.1 lb. given those figures and only at 2250rpm if 145kts is your 'chosen a/s'.

That you have 'down trim' to spare is good so you could easily go to IAS of 160kt that I initially took to be your target 'chosen airspeed'. (BTW It is IAS and density altitude that it is best to measure against) ('Others' will go on about calibrated and rectified a/s but here IAS is good enough for us.)

As you have down trim to spare I wouldn't say that you needed to try less 'plus ballast' but if you wish its nice to experiment, safely.

What I would suggest from your figures is that you go for slightly more increments, say, + another 3lbs.

Also although you say that the new ballast is snug and cannot fall out, I would suggest to mechanically secure it positively. An ally strap and a couple of self tapper screws?
The first UK made VE to fly in the UK (not mine or I piloting) had its ballast move such that it jammed the elevator train. Purely by luck it was still doing nose high fast taxi runs so all ended ok - could have been very different the next day!

Thus you are pretty well there! But if you wish to continue experimenting then, provided you are not running out of elevator in the landing configuration (which you have checked at 60kts), you could go for a 160kt 'chosen IAS' by adding , say +3lb or a frac. more., and a few more revs, 2350 to 2400 will do no harm - may well even run smoother. - No need to dig into your nice 12.1 lead block ;^)

If I've missed anything please feel free to ask and I'll respond whatever to help..

- Sounds all good - no going back now, at last you're beginning to enjoy the Eze experience!!

Best with it,

Mike T


On Sunday, 21 July 2019, 23:48:23 BST, 'Marcus Borom' borommarc@... [canard-aviators] <canard-aviators@...> wrote:

 

 

 

Hi Mike,

 

I went out early this morning to beat the heat and try my new W&B.  Ambient was 87F with low humidity.

Temperature was scheduled to climb to 105. 

Normal for Tucson.  This is real heat.  Not a heat index.  It’s always damn hot here.

 

Here are the flight details. 

 

I added the 12.1 weight to the nose area (FS 3.0) giving me a total ballast of 35.5 lbs and flew as follows:

 

Rotated at 60 kts..

No noticeable change in TO roll. 

Altitude 6500 ft MSL

OAT 70F

Flying lean of peak

Tach 2250

IAS 140-145 kts..  That was unusually high for me

TAS from a/s indicator (with temp and altitude correction) 160-165 kts

I had down trim to spare.  No stick pressure necessary.

Elevator appeared to be in the neutral position.

Checked stall speed, full throttle.  Plane would not stall.  Continued to climb at 60kts without stalling.

I didn’t want to kick up the rpms because of the OAT and possible engine overheating.

 

I was very pleased, although, at first, a bit anxious.

 

I can try another weight less than 12.1 by removing the 10.7 lb weight in the port pocket in front of the battery and filling the pocket with lead shot.

The total ballast with the 12.1 addition is now 35.5. 

Removing the 10.7 lb weight will give me a base of 24.8 lbs.  I can add weight with sacks of recovered lead shot. 

Should I give it a try?

 

I was advised by a friend to check the incidence on my canard.  That is not an issue here.  I had to modify the canard about 18 years ago.  It was too thick.  I modified it by carefully following an aluminum template and rechecked the incidence.  Everything in that regard is copesetic..

 

Thanks for your continued interest.  You guys are great.

 

Marc  B

(not as smart as Marc Z)

 

.

 

From: canard-aviators@...
Sent: Saturday, July 20, 2019 2:38 AM
To: 'Marcus Borom' borommarc@... [canard-aviators] <canard-aviators@...>
Subject: Re: [c-a] Weight and Balance - help with choosing additional nose ballast - or not

 



Hi Marc,

I assume from your spread sheet that you are the 187lb guy and we are discounting the heavy fellow.

Yes, you are with it. What you describe indicates to me that in trimming via nose down stick pressure that you do need to increase your ballast. (Down force produced by extra ballast is cheaper, drag wise, than extra down trim force with its associated drag.)

You could go for the 12.1 lb. but time is on your side, I would try, say, +6 or +8lb first. If you can't get the stick free trim condition then carry on to the +12.1lb etc. What you don't want is to run out of pitch authority in the landing configuration also if you have a problem landing in rain the more forward CoG will not help that. That's why I would advise an incremental approach.

You will feel so much more comfortable at your chosen a/s rather than have to 'fly it' all the time - and it will run more efficiently.
(Vance made a good point, if you have the space you could put in a larger capacity battery instead of some of the ballast. I recently swapped my 14Ahr m/c battery for a 21Ahr removing about 2lb of steel plate)


A point of interest that may or may not be relevant. Re. the lower weight pilot on the spread sheet.
When my daughter was flying G-EMMY all she wanted was 'hours' complaining that the a/s meant she flew longer stages.
I put the ballast such that either of us could safely fly without having to move the ballast.
This had the effect of maintaining my higher cruise a/s at neutral trim while she, at her lower front seat weight (w second set of pedals), flew at a considerably lower a/s but also, interestingly, at around neutral pitch trim. (She eventually gave me a GIB flight and I found myself leaning forward! - she was running leaned-out at 1900/2000 rpm! )
She now flies her 'light twins' long-haul for BA. And I have the Eze to myself. ;^)

Best with it Marc, - incrementally,

Mike T

On Saturday, 20 July 2019, 01:23:20 BST, 'Marcus Borom' borommarc@... [canard-aviators] <canard-aviators@...> wrote:

 

 

 

Hi Mike,

 

I was all set to remove some nose ballast, but your post has caused me some doubt.  I generally cruise at around 165 kts TAS, and I run out of nose down trim and have to push on the stick..  Does that mean that I need a little more nose ballast?

 

I have cast a 12.1 lb nose insert that will give me a CG of around 101 (see spreadsheet).  Would you suggest that I test fly that configuration to see, if my nose trim is reduced?  I like your explanation of how balance affects efficiency.

 

Marc

 

PS

It is unlikely that a 230 lb pilot would fit in the cockpit of my LongEZ.  A 230 lb pilot presents a forward CG (but still in the first flight box) issue with low fuel.

 

From: canard-aviators@...
Sent: Friday, July 19, 2019 1:52 PM
To: 'Marcus Borom' borommarc@... [canard-aviators] <canard-aviators@...>
Subject: Re: [c-a] Weight and Balance - help with choosing additional nose ballast - or not

 

 

Hi Marcus,

You are very right to reassess your W&B after a few (15) years.

However, you are now at a stage with your Long that you ought to be refining its performance.

I recently wrote on another point "".... Add(remove) ballast as necessary to achieve your minimum trim drag at the speed you choose to fly."

It is not simply to push your CoG back as far as safely possible. I worked all my carer in aerospace, a large part of that was in 'stability and control'.. This included FBW systems that allowed reduce stability margins brought about by flying with rearward CoGs to attain more efficient flight.. (mil and civil). Mainly for tailed aircraft this is the case but for a canard aircraft things are slightly different. - the canard gives positive lift whereas a tailplane pushed down. So, by moving the CoG of a plane back if it is 'tailed' this reduces the down-thrust required from the tailplane , increasing efficiency (but reducing natural stability margins). But for a canard moving the CoG further back, incrementally, means less lift is needed from the canard - good to start with but if that means that the canard elevator is now required to produce 'down trim' to the extent of adding drag that is where the rearward CoG efficiency gain idea starts to fail.

But Forget All that, there is a much easier way. Following the quote above.....

i.e What airspeed do you wish to fly with your required load? - Say, 160kts
Then run a test with your nominally safe ballast at a reasonable CoG.. Run at your chosen airspeed (160kt) and note the amount of trim you need to maintain 'stick free' straight and level flight.
If the trim is significantly 'down' and/or you need to augment the trim for level flight with more 'nose down stick' then this indicates that you need more nose ballast. If it is 'up' then you can reduce the nose ballast. (But keep within the given CoG limits)

After an iteration or two you will be flying with slight elevator trailing edge, TE, floating above the in-line position for minimum canard drag. Thus for that flight condition you have your main-plane and canard balanced for minimum trim drag.

For the Long and VE I have found that the faster the chosen airspeed the more down trim, stick nose down force, is needed to maintain level flight, so expect to increase ballast for increased 'chosen airspeed'.

Running you spread sheet as you go will keep you inside safe limits.
I hope this is of some help. OMV.

Best with it,

Mike Tooze
O-235 VE, Last winner of EuroCAFE, in our 38th yr.

On Thursday, 18 July 2019, 19:04:22 BST, 'Marcus Borom' borommarc@... [canard-aviators] <canard-aviators@...> wrote:

 

 

 

Hi Canardians,

 

After flying for 15 years on my last weight and balance determination, I enlisted the help of George Snyder and his certified, digital scales for a re-weigh.  I am considering adding additional nose ballast, either 10 or 25 pounds..  I would like some advice on whether I should choose 0, 10, or 25 pounds of nose ballast.  The nose already has 23.4 pounds of ballast installed.

I am attaching an Excel spreadsheet with the comparisons showing the effect on the CG for various scenarios of loading.  I have indicated the position for the CG for each of the loadings, and color coded each as follows:

 

Green (in the first flight box),

Yellow (in the CG box, but aft of the first flight box)

Pink (in the CG box, but near the aft limit)

Red (dangerously aft of the CG box)

 

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

 

The CG box is shown at the bottom of the spreadsheet. You can play with the weights by just changing them.

 

Thanks in advance for your input.

 

Marc Borom

LongEZ  N966EZ

Ryan Field

Tucson, AZ

 

Virus-free. www.avg.com

 

 

 



 






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