Jump to content
Sign in to follow this  
FlyingMonkey

Propeller CG position

Recommended Posts

Hello...

I have to recalculate my W&B for my new E-Props propeller.  My factory W&B sheet does not include the prop as a separate item, I guess it was included in the basic airframe calculation.  Does anybody know the CG position/Arm of the prop in relation to the datum (wing leading edge) so I can change the prop weight and recalc the new CG?  The Battery is at -22.83", so I'm guessing the prop is somewhere like -40" to -44".

Thanks!

 

Share this post


Link to post
Share on other sites

With the aircraft reasonably level attach a weighted string to the leading edge,  mark the floor. Then do the same at the middle of the prop assembly. Then measure the distance with it parallel to the fuselage .

Share this post


Link to post
Share on other sites

The propeller is in your equipment list. It will have the weight and the location. Mine for example (do not use!) shows -49.6 inches and 13.6 lbs.

After you install the new prop, don't forget to update it for your ease in the future. I don't think equipment lists are required on E-LSA.

Share this post


Link to post
Share on other sites
18 minutes ago, Anticept said:

The propeller is in your equipment list. It will have the weight and the location. Mine for example (do not use!) shows -49.6 inches and 13.6 lbs.

After you install the new prop, don't forget to update it for your ease in the future. I don't think equipment lists are required on E-LSA.

If by "equipment list" you mean the factory CG sheet with the equipment list down the right side...then no, my prop is not on it.

 

Share this post


Link to post
Share on other sites

I would do as Madhatter said. I would probably drop one from the leading edge on both sides and snap a chalk line between. The one for the tail and the center of the firewall, but extended beyond the prop. Then finally one from the fore and aft center of the prop. Measure from where the centerline crosses the leading edge line to the propeller line and you have your number. The other option is to defuel, level, and weigh the airplane, and get a new actual empty weight and CG.

Share this post


Link to post
Share on other sites
19 minutes ago, Tom Baker said:

I would do as Madhatter said. I would probably drop one from the leading edge on both sides and snap a chalk line between. The one for the tail and the center of the firewall, but extended beyond the prop. Then finally one from the fore and aft center of the prop. Measure from where the centerline crosses the leading edge line to the propeller line and you have your number. The other option is to defuel, level, and weigh the airplane, and get a new actual empty weight and CG.

That sounds like the best way to get an accurate number.  I'm not doing an actual weighing unless it becomes legally required for some reason.  That seems to always cost people useful load.  ;) Thanks guys.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
Sign in to follow this  

×
×
  • Create New...