highflyer77 Posted June 13 Report Posted June 13 Dear Mooniacs, I just got my aircraft newly painted. As standard procedere the aircraft´s w&b was done new. Unfortunately, they choose to do the w&b with the "full fuel method"... :-((( . As I have installed the monroy l/r-fuel STC: where do I find the arm for the rear tanks ? Standard tanks are 122 cm (48 inch). I found something inofficial that reads 168 cm (66 inch) for the rearward tanks, but I don´t know where to get the "official" numbers to forward to the maintenance facility... Thanks for your help ! Quote
Fly Boomer Posted June 13 Report Posted June 13 22 minutes ago, highflyer77 said: Dear Mooniacs, I just got my aircraft newly painted. As standard procedere the aircraft´s w&b was done new. Unfortunately, they choose to do the w&b with the "full fuel method"... :-((( . As I have installed the monroy l/r-fuel STC: where do I find the arm for the rear tanks ? Standard tanks are 122 cm (48 inch). I found something inofficial that reads 168 cm (66 inch) for the rearward tanks, but I don´t know where to get the "official" numbers to forward to the maintenance facility... Thanks for your help ! Should be in your installation document. Mine says: Center of gravity (M20C, M20E) . . . . . 66.0 inches Center of gravity (M20F thru M20K) . . . 71.0 inches 1 Quote
philiplane Posted June 13 Report Posted June 13 1 hour ago, highflyer77 said: Dear Mooniacs, I just got my aircraft newly painted. As standard procedere the aircraft´s w&b was done new. Unfortunately, they choose to do the w&b with the "full fuel method"... :-((( . As I have installed the monroy l/r-fuel STC: where do I find the arm for the rear tanks ? Standard tanks are 122 cm (48 inch). I found something inofficial that reads 168 cm (66 inch) for the rearward tanks, but I don´t know where to get the "official" numbers to forward to the maintenance facility... Thanks for your help ! They need to drain the system and weigh the aircraft empty. This arrangement is hard enough to fuel, there is no way they can be certain how much fuel is "full fuel". Drain it. 5 Quote
highflyer77 Posted June 13 Report Posted June 13 Absolutely my opinion. They also did the mistake not having the airframe in the position required when doing the weighing (spirit level on the row of rivets on the fuselage). They just put it on the scales on the workshop floor, I assume. This falsifies the weight reading in such a way, that the CG shifts rearward by 1,5 inches (IIRC, the wrong weighing procedure shifts about 30 kgs. from nose gear to the main gear...). When I bought the plane, the CG sheet showed an empty CG of 48.05 inches. I reweighed everything myself (unofficial) - weight was correct, but the CG moved forward to 46.7 inches. This gives you a lot of possible weight in the rear seats and baggage compartment, compared to 48.05 inches... As the plane was stripped and paint, the offer also included a new w&b (done by a different company than the paint shop). The paint shop did a perfect job. But it´s a PIA when you expect to get a new, correct w&b after repainting the aircraft (I even sent them the instructions for determining the correct values...) , and then it´s just useless... Theis just said: No, we don´t do the "empty plane method" - it´s too much work do drain the fuel. And I am quite sure that they have not nivelled the fuselage by means of using a spirit level. Grrrrrhmpfff... But what do you think - isn´t she a beauty ??? I´ll just do a new w&b sheet with my A&P/maintenance facility ! 2 Quote
1980Mooney Posted June 13 Report Posted June 13 5 hours ago, philiplane said: They need to drain the system and weigh the aircraft empty. This arrangement is hard enough to fuel, there is no way they can be certain how much fuel is "full fuel". Drain it. Absolutely correct. @highflyer77 there was a recent topic about Monroy tanks and @Pinecone commented: "If you fill main with aux empty, fuel starts moving into aux. So when you stop filling main and put on the cap, the level in the main is still going down. So you fill the aux, but the main is not full, so the level in the aux goes down and leaves you short of full. Filling aux first means fuel is moving from aux to main. Then you fill the main, which reduces flow from aux to main. So you then top the aux after doing the same to the other side and you are much closer to full." The shop that did the W&B had no way to accurately know how much fuel that you had in the tanks to start with - and they had no way of knowing if they actually filled the Monroy and Mains all the way to "Full Fuel". Quote
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.