Gary O.
N181RL
661 746-4780
-----Original Message-----
From: Sport_Aircraft@yahoogroups.com [mailto:Sport_Aircraft@yahoogroups.com] On Behalf Of Jim Bair
Sent: Sunday, October 04, 2009 6:58 AM
To: Sport_Aircraft@yahoogroups.com
Subject: Re: Light-Sport Aircraft Yahoo group WSC Weight and Balance
> >More likely W&L Weight and Loading.
> Not really. The Weight and loading is easy.
> We add your weight, my weight, the fuel, and the trike,
> and see if it adds up to less than 992. It does.
> I can do that in my head.
> No, our concern is what you mentioned about the
> nose wheel hanging lower.
You must have done this plenty of times Jim,
... it must be quick and easy for you.
How about doing just one more for the considered
loading (Richard doing his checkride with you),
and put it in the group files?
front seat 300
rear seat ~178
fuel 30
I've never seen a sample of a WSC weight and balance
in any text book.
(showing as you promise "nosewheel height")
Thanks,
Mike
WSC W&B is like any other W&B, so there doesn't have to be a sample of WSC
specific W&B in the textbook. In almost every textbook I have seen there is
the generic teeter totter examples so that the pilot understands the concept
of weight x arm = moment and that when all the weights are added up and all
the moments are added up, you simply divide the total moments by the total
weight and you have the CG. In trikes, the CG is typically "in the
vicinity of" the rear seat, and simply has to be behind the hang point for
the rear wheels to hang lower than the nose wheel. Once the CG of the
trike is determined (this involves weighing the trike with scales at each
wheel) it is simple to measure out the locations of the front seat, rear
seat, fuel tank, baggage area, etc., and plug in the numbers. I made a
spreadsheet for my W&B worksheet (or W&L worksheet, I don't care what you
call it. Same math.) for each trike so I could plug in the numbers for each
one with some various loading scenarios. I don't have the DTA one here at
the house, but I do have a copy of my old aerotrike paperwork and for a 300#
guy, which I happened to choose for the worst case scenario, the math showed
that the CG was still aft of the hang point location, meaning the trike
would hang lower in the rear than the front.
I did look in the SP written test study guide and you are correct, the
chapter on W & B is really lame. Even for fixed wing people there is almost
nothing on W & B. Probably because at the LS level, our loading options are
so limited that there is more concern with weight than with the balance
part. However, when we have a triker say he'd had a problem with landing on
the nose wheel a couple of times and it wasn't very pleasant, that should
tell him that he should figure out what's going on. Any textbook at the
Private Pilot level and above will have some info on how to do basic weight
and balance and certainly an instructor textbook should have it so when you
say you haven't seen WSC specifically addressed, I believe you. However,
you will be able to figure it out for a trike because the concept is no
different.
Personally, I didn't use the EAA supplied W&B paperwork. I made my own
because it was more complete and had examples of a variety of loading
scenarios to cover about any contingency. A story that was related to me
once underscored the importance of understanding this and knowing how to
calculate it. Triker is approached by a cameraman wanting ot attach a movie
camera to nose. Triker says OK. Next day, cameraman shows up with a camera
twice as big and attached to about a 3' boom to attach to the nose. Warning
bells go off in triker's head. He understands W&B and does a calculation
and determines nose will be hanging low. That's why every triker should
understand the concept. So when someone comes out with something out of the
ordinary, be it a camera on a boom or a 320# student in front, he knows to
do the WxA=M thing and figure his CG. Only tools needed are a tape measure,
scales, and some sort of plumb bob for extra accuracy.
Jim
__._,_.___
No comments:
Post a Comment