Heron flightplanning

[Anders Samuelsson]

Hello,

Iäve bought a real manual for the Heron and have been trying to put together a planning document, with some boxes for the flight, route, fuel, CG, and stuff. I have used the real limits from my manual (the chart in the lower right corner) and the information from the aircraft.cfg file for the CG planning part. I do have a problem with the math though. As it is set up now with a empty arm of 0 and the rest I could actually load a ton of cargo in the furthest aft position (rear cargo) and it would still be within limits, that seems a bit wrong.

In a real aircraft would the empty arm be 0?

I'm not a real pilot so I could have made a mistake somewhere, please let me know.

This document is in KG but I am working on a lb version too.

http://www.anderssamuelsson.se/filer/heron_weight.pdf

Edit: added some things and among others the fuel, think I calculated the arm in inches correctly and then suddenly where I put the remaining weight got very important Still any feedback is very much welcomed!

[cstorey]

Weeell.... that certainly doesn't look like the manufacturer's load sheet to me, and I fear that it has got its units radically mixed up which is just one of the reasons why you are having such trouble . The arms which are given are most certainly not in inches from the datum, and are much more likely to be in metres.( and the resulting moments will be kgM and not kg-ins) . Also, the load sheets that I have done ( now too far in the past to remember with certainty ) all involved a summation of the moments forward and aft of the CG datum , and not a division of those moments by the weight . The a/c weight is irrelevant to the CG position : it is the added weights which move the position fore or aft - this is why the lever arm for the a/c is NIL .

Edit : having looked at it again I am wrong and it IS showing the lever arms in inches - I must wear my glasses in future !

[DaveB]

Are these any good to you Andy or are they what you already have..





ATB
DaveB

[Tomliner]

I'm going to ask an incredibly stupid question, but on the real thing how did you know where the CG was and how it would vary with load to be able to stay within limits? EricT

[DaveB]

Hi Eric

If you read the final passage on the last page.. it tells you "A datum plate is fixed to the port side of the fuselage, aft of the fuselage levelling peg".

Therefore.. all those who can read should know where and how to load up

ATB
Dave

[Tomliner]

B*ggeration! Thanks Dave. EricT
ps I did say it was a stupid question!

[DaveB]

I did make that post ever so slightly tongue in cheek and hoped after I'd posted that you wouldn't be offended

I think all aircraft (or aircraft of a certain size) have 'visible' datum plates don't they? I've always assumed so I don't know if passengers were weighed or given a visual 'once over' prior to boarding a Heron as they are on say, the Rapide but you wouldn't want to be in a situation whereby you'd a load of fat folk on one side and skinny folk on the other. I know before boarding a Rapide, you're weighed and your weight noted. The ground staff then move you to the aircraft and physically seat you where they want you so the passenger weight is distributed evenly around the CG. This may have happened with the Heron too.. I really don't know.

ATB
DaveB

[Tomliner]

No Dave, of course I'm not offended I should have read your post fully before I replied. Eric T

[Anders Samuelsson]

Thank you guys for your input.

I studied the information on how the aircraft.cfg is constructed and I had the units mixed up. I have now changed all the units in the arm part to inches (in the cfg file it is feet).

The reason why I included the aircraft weight and arm was that I read it in the FAA's manual for weight and balance but there the aicraft hade a arm of 48 or something meaning I assume that the empty aicraft isn't perfectly balanced. In the heron cfg file the aicraft is at arm 0. Anyway I removed the aircraft weight part.

I'v tried it out with different loads and it seems to add up pretty ok with both the manual that I have and the screenshots of Daves, for instance, in this new version if I only have one pilot and the rest of the aircraft loaded with pax (no luggage) I have to put some ballast in the front cargo compartment to stay within the limits.

It might never be perfect, but I think this version should work with the aicraft.cfg file pretty good. But still more input is always welcomed. There'll be a lb version too.

http://www.anderssamuelsson.se/filer/heron_weight.pdf

[DaveB]

I think it's probably true to say that the aircraft isn't perfectly 'in balance' when unloaded. I've seen many a shot showing the aircraft with a 'stay' under the rear fuse on an empty aircraft

Glad it's all coming together for you Andy

ATB
DaveB