Empty weight envelope

[Bill Hart]

Today I came accross a document I don't recall ever seeing. It is a model 170 empty weight envelope. I am hoping someone can tell me where it came from as it is not part of the flight manual but it is about the same size and looks to be about the same age.

[jrenwick]

Could you scan it and post it here? That might help people know what you're asking about!

[canav8]

Bill the only acceptable W&B Envelopes are that of the Type Certificate Data Sheet for the 170. In there you will find one for floats and one for Land. Those should be the reference for any weight and balance computations unless you have an STC that has modified the envelop for the STC. Respectfully, Doug

[Bill Hart]

Bill the only acceptable W&B Envelopes are that of the Type Certificate Data Sheet for the 170. In there you will find one for floats and one for Land. Those should be the reference for any weight and balance computations unless you have an STC that has modified the envelop for the STC. Respectfully, Doug

I will have to scan it and try to post it. This document looks like it gives CG info for full gas and passengers with bags. It is a little disconcerting as by this document I have been out of limits every time I fly with passengers.

[Bruce Fenstermacher]

Bill, tell me how this document, which I assume is not part of your aircraft records, would have your aircrafts actual weight and moment.

The EC145 I fly at work is extremely nose heavy compared to most others of the same model. The basic weight and arm for it is several hundred millimeters in front of every other aircraft of the same model the company owns because of the way it is configured. All aircraft have to be considered on a case by case scenario.

[Bill Hart]

Ok I have sent the scan to Bruce in hopes he can post it here.

On this chart you enter from the left side with the aircrafts empty weight and move across to the right til you reach the aircrafts CG. and if you are above a line you have to reduce fuel to carry four people plus baggage. I get all of this I had just not seen it before until I started cleaning up my arrow documents after installing a new interior and was curious why have a document like this when there is a weight and balance envelope on the TCDS .

[Bruce Fenstermacher]

Here is the graph Bill sent.

170 empty weight envelope.jpg

First this is not a full W&B graph and can not be used as such. What this appears to be is a graph to quickly determine if you could put someone in the back seats and how that would relate to limiting baggage and or fuel.

I think this is a very interesting document for several reasons and here are my observations. First I think it is part of a bigger exercise. In other words there is information needed that is missing to use this sheet. In the first example it says to use empty weight and arm and says it is apparent if 2 people were carried in the back seat baggage would have to be limited. My question is how about people in the front seat? Where do you account for the rest of the loading? I would have to do a lot of examples with a full W&B program to see how this graph actually relates.

Second who made it? Interesting to note that the baggage total only goes to 100 lbs. As we have recently discussed elsewhere the limit of 100 lbs in the baggage was only for a VERY short time so this is a very early document.

I'm thinking this graph was made by Cessna as part of an educational package of some sort for their about to be or newly released 4 place airplane.

[GAHorn]

...Interesting to note that the baggage total only goes to 100 lbs. As we have recently discussed elsewhere the limit of 100 lbs in the baggage was only for a VERY short time so this is a very early document.....

I don't believe we found this to be the case that "100 lbs" was used for a short time. I believe we found that baggage limitations specified in specific AFMs might reduce the baggage capacity for specific airframes, most likely due to other installed equipment.

In other words, the TCDS allows all models 170 a max bag capacity of 120 lbs...but particular airplanes might experience a reduction of that capacity due for other mods/equipment. (AFMs are specific to serial numbers.)

Therefore the document in this discuusion thread likely applies to a specific serial aircraft.

[Bruce Fenstermacher]

Actually George what we concluded was that all the current AFMs and the TCDS now agree that in all models the baggage is limited to 120lbs.

We never concluded that at one time the limit wasn't different and as I pointed out at that time I have evidence in the form of original AFMs that limits the baggage to 100lbs and in addition to the AFMs I actually have an original baggage decal in my aircraft that says the limit is 100lbs.

100_4600.JPG

So I think it is clear that someone at Cessna thought the baggage compartment should be limited to 100 lbs, at least for a short time period. This document whether from Cessna or another source was using the limit at the time it was created.

[jrenwick]

This document looks to me like it's for a 1948 ragwing 170, as its title suggests. Many later models, as configured today, have an empty weight outside the envelope of this chart, but 1948 models typically weighed less than A- or B-models, didn't they?

John

[Bill Hart]

This document looks to me like it's for a 1948 ragwing 170, as its title suggests. Many later models, as configured today, have an empty weight outside the envelope of this chart, but 1948 models typically weighed less than A- or B-models, didn't they?

John

That is what I was hoping for John as my A model is way out side this envelope. It had me scared for a moment. I saw the 170 title but couldn't figure out why it was stuck behind my flight manual in with my weight and balance.

I was thinking that someone on here with a 48 was going to pipe up and tell me what it was.

[DWood]

Bill:
That graph is included in my 48 AFM.
Dan

[Bruce Fenstermacher]

Dan you mean the owners manual. The AFM is the single sheet of paper which doesn't have this graph. (we've got to keep everyone straight )

[DWood]

Hi Bruce:
I have photo copies of my AFM at home and it is at least 2 pages with this as the third page. I will get to the airport this weekend and see if the one in the plane or the project is more definite. The second page of the AFM includes the CAA signature and the graph is a third page (the pages are loose) that might not belong with the AFM. This graph is NOT included with the pre delivery flight test report which does include a weight and balance.
Thx,
Dan

[DWood]

Bruce:
I just went page by page thru the Owners Manual and that graph is NOT in the owner manual.
Dan