---------------------------------------------------------- Cessna-List Digest Archive --- Total Messages Posted Sun 09/07/08: 2 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 07:24 AM - Re: wt and balance (Gardiner Mason) 2. 08:22 AM - Re: wt and balance (Daryl Medd) ________________________________ Message 1 _____________________________________ Time: 07:24:01 AM PST US From: "Gardiner Mason" Subject: Re: Cessna-List: wt and balance Daryl, thanks for getting back to me. The plane was weighed with full tanks ina level attitude and it came in 5 lbs heavier than it was before replacing the starter and alt. with the light weight. I don't know the CG yet, but I suspect it is going further aft. With that in mind, do you know if you can get a field approval to mov the battery forward. It seems to me that the STC's. for the starter and alt. would address these issues. Cheers, Gardiner Mason ----- Original Message ----- From: Daryl Medd To: cessna-list@matronics.com Sent: Saturday, September 06, 2008 8:39 PM Subject: Re: Cessna-List: wt and balance Yes, sounds like you need some help with this. Your mechanic will need to enter the removal and replacement of the starter and alternator. The STC instructions likely include a note to amend the weight and balance. There will be moment arms, weight of the components removed, and weight of the components installed that need to be calculated in the amendment. The alternative to the calculated weight and balance amendment is to reweigh the airplane as you refer to in your post. There are specific procedures for that too. The fuel quantity has to be known precisely, but even better is to drain all fuel. The aircraft needs to be leveled per the service manual before weighing. You don't mention if the tail was on the ground when you weighed it, or the airplane was level. The manual will call for the plane to be leveled to a certain reference, which turns out to be near a level flight attitude. Once the new weight and balance are determined, then you can do some sample calculations to see if the airplane is within limits with a typical load for your mission. Daryl ----- Original Message ----- From: Gardiner Mason To: cessna-list@matronics.com Sent: Saturday, September 06, 2008 1:37 PM Subject: Cessna-List: wt and balance I have just installed a skytec starter and a light weight alternator. I have removed about 20 pounds from the front end ,and now I am worried that I will be too tail heavy to carry any luggage. Oh, I have a cessna 140 with a C90.....Is it possible to move the battery to ahead of the firewall? Frustrated because I like to carry camping gear behind the seats. I have not done a compleat wt n balance yet ,but with full fuel the tail weighs 90 lbs. Any feedback would be greatly appreciated. Gardiner Mason href="http://www.matronics.com/Navigator?Cessna-List">http://www.matron href="http://forums.matronics.com">http://forums.matronics.com href="http://www.matronics.com/contribution">http://www.matronics.com/c ------------------------------------------------------------------------- --- 05/09/2008 7:05 PM ________________________________ Message 2 _____________________________________ Time: 08:22:34 AM PST US From: "Daryl Medd" Subject: Re: Cessna-List: wt and balance Just google FAA STC and you'll come to a page where you can search for a list of every STC ever approved for the 140. I don't know off hand if there is a battery moving STC. I responded to your question mostly because it is so important that you amend the weight and balance for your aircraft. You need that information to ensure that you don't end up loaded out of limits and encounter handling difficulties. I'm not licensed to do it for you, and it's something that you need to be with the airplane to complete. ----- Original Message ----- From: Gardiner Mason To: cessna-list@matronics.com Sent: Sunday, September 07, 2008 8:20 AM Subject: Re: Cessna-List: wt and balance Daryl, thanks for getting back to me. The plane was weighed with full tanks ina level attitude and it came in 5 lbs heavier than it was before replacing the starter and alt. with the light weight. I don't know the CG yet, but I suspect it is going further aft. With that in mind, do you know if you can get a field approval to mov the battery forward. It seems to me that the STC's. for the starter and alt. would address these issues. Cheers, Gardiner Mason ----- Original Message ----- From: Daryl Medd To: cessna-list@matronics.com Sent: Saturday, September 06, 2008 8:39 PM Subject: Re: Cessna-List: wt and balance Yes, sounds like you need some help with this. Your mechanic will need to enter the removal and replacement of the starter and alternator. The STC instructions likely include a note to amend the weight and balance. There will be moment arms, weight of the components removed, and weight of the components installed that need to be calculated in the amendment. The alternative to the calculated weight and balance amendment is to reweigh the airplane as you refer to in your post. There are specific procedures for that too. The fuel quantity has to be known precisely, but even better is to drain all fuel. The aircraft needs to be leveled per the service manual before weighing. You don't mention if the tail was on the ground when you weighed it, or the airplane was level. The manual will call for the plane to be leveled to a certain reference, which turns out to be near a level flight attitude. Once the new weight and balance are determined, then you can do some sample calculations to see if the airplane is within limits with a typical load for your mission. Daryl ----- Original Message ----- From: Gardiner Mason To: cessna-list@matronics.com Sent: Saturday, September 06, 2008 1:37 PM Subject: Cessna-List: wt and balance I have just installed a skytec starter and a light weight alternator. I have removed about 20 pounds from the front end ,and now I am worried that I will be too tail heavy to carry any luggage. Oh, I have a cessna 140 with a C90.....Is it possible to move the battery to ahead of the firewall? Frustrated because I like to carry camping gear behind the seats. I have not done a compleat wt n balance yet ,but with full fuel the tail weighs 90 lbs. Any feedback would be greatly appreciated. Gardiner Mason href="http://www.matronics.com/Navigator?Cessna-List">http://www.matron href="http://forums.matronics.com">http://forums.matronics.com href="http://www.matronics.com/contribution">http://www.matronics.com/c ------------------------------------------------------------------------- - 05/09/2008 7:05 PM href="http://www.matronics.com/Navigator?Cessna-List">http://www.matron href="http://forums.matronics.com">http://forums.matronics.com href="http://www.matronics.com/contribution">http://www.matronics.com/c ------------------------------------------------------------------------- ----- Checked by AVG. 05/09/2008 7:05 PM ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message cessna-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Cessna-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/cessna-list Browse Digests http://www.matronics.com/digest/cessna-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.