Weight distribution

[oklahotshot]

Am installing MT three blade prop , 26 lbs lighter than existing Hartzell, IA is talking of adding weight up front ,,, im hoping we can remove weight from tail section, it does have auxiliary javelin tank under backseat, wondering what some of you more knowledgeable folks input would advise, project is suppose to happen next week

[Metal Master]

Most of these aircraft that have had a Lycoming O-360 or TCM IO-360 engine and constant speed prop installed have to much weight forward to begin with and removing 26 Lbs forward would be a benefit. And while having the Javelin Tank in the back would be a good thing depending on the fuel you have in it to help shift the loaded CG I find it hard to believe you have a problem. Just adding weight without knowing the Calculated or weighed empty weight CG is just not the right thing to do. I would recommend weighing the aircraft and mathematically calculating many different flying conditions and weights to see where it puts you in the flight envelope. Bruce posted links on the 170 association web site which can be found in a search for a weight & balance Calculator, there are others on the internet. I have my own developed on an excel spread sheet that I can experimentally install different pilot weights fuel load and baggage loads to see where it puts me within the CG envelope. It also shows me the remaining useful load. Additionally I can imagineer loading changes of proposed installed equipment such as props , landing gear tires and wheels etc. The pictorial CG graph on it shows me where on the loading graph the new calculated CG lies. However using any of these Load Graph tools depends on having Good numbers to begin with. Here is a link to Bruces forms. Found using the search function.
http://cessna170.org/forums/viewtopic.p ... Calculator
Using these tools is cool because it allows you see what happens to the flying CG as you burn fuel for example out of the Javelin Tank.

[Bruce Fenstermacher]

What Jim said.

Do not do anything removing something until you spend time with good numbers and a spread sheet.

If you don't understand Excel or spread sheets ask me for help. I'd be happy, given your numbers, to plug them in and give you all the scenerios you need.

[bagarre]

If it hasn't been done recently, I'd put the airplane on a set of scales and calculate actual weight and balance before doing anything.
It's odd for an IO-360 with a constant speed prop to be tail heavy.

[c170b53]

Piling on
Maybe I missed it but which conversion do you have? Do you believe some weights have been added aft for the engine conversion? Was the battery moved off the firewall and into the aft fuselage? Do you believe your W&B to be correct? (Now I'm really piling on ) (The other Jim )

[oklahotshot]

Agree with everyone , we will use certified scales & have real numbers to see where CG limits are at before & after prop swap, it does have the 0 - 360 conversion, Masa STOL, heavily modified, etc ( thanks to Marvin Nichols tlc thru the years ) wanting to get rid of 100hr AD & rpm limitations with the Hartzell prop , thanks for the help, very informative bunch on here, have enjoyed soaking up all the knowledge & reading archives on the 170 topics. Kudos to a welcoming group of my peers

[bagarre]

Would love to see a few photos of the ole bird when you get the chance.

[DaveF]

When I installed my MT I was glad to take the 20 pounds off the nose of the airplane, which has a Lycoming O-360. It's still nose-heavy.

[wingnut]

Does the MT Prop STC cover the 170 series airframe and the Lycoming engine?

[blueldr]

What is the result of the preliminary calculation using your present weight and balance data? I would suggest a new weighing if the present data is old.

[DaveF]

Does the MT Prop STC cover the 170 series airframe and the Lycoming engine?

Yes, STC SA02245CH covers multiple airframes, including the 170, that are equipped with the IO- and O-360.

[oklahotshot]

Thanks for ya'lls help , started this a m on prop change , will try to keep progress posted (not one of my strong points,ha) excited bout the MT , appreciate all Johns N. time & help, good folks to deal with !

[bagarre]

Would be nice if MT made an option for the Continental IO-360 as well.

[flyboy122]

Am installing MT three blade prop , 26 lbs lighter than existing Hartzell, IA is talking of adding weight up front ,,, im hoping we can remove weight from tail section, it does have auxiliary javelin tank under backseat, wondering what some of you more knowledgeable folks input would advise, project is suppose to happen next week

Dave, Right?

Think I met you at Oshkosh. If so I'd be amazed if you needed nose ballast with those big tires and stuff in the panel.

Dennis

[oklahotshot]

No big tires yet or the Oskosh adventure but definitely in the cards, discovered today there was only three pounds difference in props and the ol bird seems alil heavy, am hesitant to say anymore till I have paperwork complete & in front of me, know this crowd will educate me