[armondo]

Flying rv-6, 0360-a1a, Hartzell cs. am about to change to Worldwind 200rv (18 lbs. lighter on the nose)
wondering how far aft cg will change for first flight. the aircraft will be re-weighed eventually. If anybody has made the similar change, would like to know what you old and new cg is. My present cg is 70.6" at 1136 lbs. empty. Would appreciate any information. Many thanks. Armondo

 

[alpinelakespilot2000]

Flying rv-6, 0360-a1a, Hartzell cs. am about to change to Worldwind 200rv (18 lbs. lighter on the nose)
wondering how far aft cg will change for first flight. the aircraft will be re-weighed eventually. If anybody has made the similar change, would like to know what you old and new cg is. My present cg is 70.6" at 1136 lbs. empty. Would appreciate any information. Many thanks. Armondo

Not sure if I'm reading your question right, but it sounds like your not asking about flying qualities but simply math.

Since you know your current weight and balance and you know the weight difference of the prop, all you need to know is where the datum line is on the plane (should be in the POH and weight and balance paperwork), and then it should be a simple matter of doing the math from there.

 

[rvbuilder2002]

Flying rv-6, 0360-a1a, Hartzell cs. am about to change to Worldwind 200rv (18 lbs. lighter on the nose)
wondering how far aft cg will change for first flight. the aircraft will be re-weighed eventually. If anybody has made the similar change, would like to know what you old and new cg is. My present cg is 70.6" at 1136 lbs. empty. Would appreciate any information. Many thanks. Armondo

Armondo,
You placed this post in the classified (stuff for sale or wanted) section. Maybe a moderator can move it for you.....?

It maybe something you already know...but for your airplane to be legal to fly after you do the propeller change, you need to do a new W&B computation befoer it is flown. Actually re-weighing the airplane is not necessary.

All of the questions you are asking can be calculated in just a few minutes by anyone that knows how to do weight and balance computations. All you will need to do is measure the weight of the current propeller after it is removed, and the weight of the propeller you are installing (before it is installed). The only other thing that is needed is the arm distance of the propeller from the datum (measure the distance from the center of mass of the propeller to what ever point is listed as datum in your weight and balance paperwork).

I am strongly encouraging you to do a W&B before you fly after the propeller change. 1136 lbs is moderately heavy for a 6A (even with a hartzel prop.). Depending on where the excess weight is located, changing to a lighter prop could have a rather negative effect on the empty C.G. (which apparently you already know since you are asking the question).

In addition...You need to also check your operating limitations to see what is required after incorporating a major change (this is a major change).

 

[PCHunt]

Major Change vs. Phase I

............ In addition...You need to also check your operating limitations to see what is required after incorporating a major change (this is a major change).

Good Point. Most, if not all, OP limits require placing the plane back into Phase I testing for 5 hours, and notification of such via letter to your local FSDO after a "major change". But whatever your OP Limits say is what you do.

Don'cha just love the paperwork?

Will defer to DAR's who might want to clarify.

 

[rv8ch]

Flight testing

I'm sure others with more experience that I have will chime in, but changing from a Hartzell to a WW prop seems like quite a major change in terms of flight characteristics and W&B. It seems taking a few hours to ensure that everything works as expected is a pretty reasonable thing to do, even if it was not "required".

About the Weight and Balance, as others have said, if you are not comfortable doing this calculation, I recommend taking some time to understand it. I know that there are a lot of pilots that don't like the math, but it is quite simple once you have done a couple, and I believe it is required knowledge. Having a CG that is too far back can be rather unpleasant, to say the least.

 

[N941WR]

Good Point. Most, if not all, OP limits require placing the plane back into Phase I testing for 5 hours, and notification of such via letter to your local FSDO after a "major change". But whatever your OP Limits say is what you do.

Don'cha just love the paperwork?

Will defer to DAR's who might want to clarify.

FYI - I checked my paperwork and with my FISDO about changing my current FP Catto to a new Catto with a different pitch. You guessed it, back to Phase 1 for five hours.

Make sure you are legal! If you are not legal and have even an incident, such as I had, the insurance company will check all your paperwork. If anything is not in order, they will deny your claim.