Hello, I am from Argentina? I have a comanhe 250 1960 with 60 galon and I want 90 galons, so my question is with the tip tanks can I fly with 4 peoples and the bagagge with 100 lbs as I normally do? Do i losse someflying performance??
Thanks

Hi Ruy,

Welcome to the ICS Forum.

You should get the specifics from the tip tank vendor J.L Osborne. I can only speak from my Twin's view. The STC for the twin raises the gross weight from 3600 to 3725 - ONLY IF the weight is fuel in the tip tanks. I don't know if the STC for 250's is different. http://jlosborne.com/tip_tanks.htm

After that you just have to do the weight and balance calculations for your aircraft - as you already know.

Bienvenidos a la Sociedad Internacional de Comanche y tambien muchos felicidades cordiales por su propriedad del modelo supremo de la familia Piper - el Comanche!!

I have owned my 1959 Piper Comanche for 33 years. It is equipped with tip tanks. The gross weight of the basic 1959 "250" is listed as 2800 lb. This was increased to 2900 lb. a year or two later. Yours may be listed as 2900 lb.; I don't know.

When equipped with tip tanks, the gross weight is increased to 3000 lb. PROVIDING the extra weight is in the form of fuel residing in the tip tanks. PLEASE NOTE that the gross weight allowable remains at 3000 lb regardless of whether your aircraft is listed at a gross weight of 2800 or 2900 lb. In other words, if your plane was listed as having a gross weight of 2900 lb. without the tip tanks, adding the tip tanks will increase it to 3000 lb - NOT 3100 lb.!

The earth was still quite young when the airplanes were built, and you may find that there is not as much weight and balance information available as we might wish regarding the addition of these tip tanks. I did communicate with the late Maurice Taylor about where the weight and balance envelope might reside when the tanks were filled; he did provide me with his carefully calculated opinions. Please contact me at c-flhv@magtech.ca and I will forward them to you.

I can tell you with great certainty that you will never regret installing these extra tanks.

Donald Ostergard, ICS #3263
Drumheller, Alberta, Canada
c-flhv@magtech.ca

I have an empty weight of 1713 pounds and useful weight of 1286. With 90 gallons of fuel I will have 746 pounds available, which means I could still take 4 186 pound people flying. Since most of our friends weigh less than that, we can take 4 people and baggage. Flying the Comanche at gross has shown me it still handles very well, and I've worked multiple weight and balance equations and have been very hard-pressed to get it out of CG.

I think Don's comments above may be incorrect. I've heard from several sources that the gross weight increase to 3,000 pounds is a bit unusual in that it doesn't require any fuel to be in the tip tanks to use the higher gross weight. Yes, I'm suggesting that having the tip tanks lets you carry an additional 100-200 extra pounds around with you!

At any rate, the tanks work very well, look great, and are easy to manage.

I know for the Twin Comanche it clearly states that with wing tips the gross weight is 3725 pounds with
the additional words stipulating that any weight above 3600 pounds must be in the form of fuel in the tip tanks.
No problem actually, if you are only going shorter distances fill the mains and you can fill the cabin, leaving the other tanks empty. If you need more range you get another 125 pounds of fuel for free as long as you put that fuel in the tips.
if you need even more fuel for the trip, offload the motherinlaw and use the auxs..

Gary

Gary, Gary Gary ... we're going to tease you a bit as this comes from my husband via our combined sense of humor - We think you'll recognize the tune.
Be kind to your web-footed friends
For a duck may be somebody's mother

Our lyrics
Be kind to your high-flying friends
Instructor may be somebody's mother-in-law

In husband's case, his mother-in-law was his flight instructor from Cherokee 140 through Twin Comanche and Instrument rating. We always got a good laugh out of this when he was learning - especially when a new acquaintance would ask, "Does she know anything?" Ken would stand a little straighter and proudly say, "Well, she is ATP." Google Marion Jayne pilot if you want to read more about her.

Mom died in 1996 with ovarian cancer but the humor lives on in our memories so Ken laughed and said to your post, "If Mom (his mother-in-law) were still alive, I would not throw her out to get more useful load and I can hear her say, well, we'll just need to lose some weight if we want to carry more fuel.":-)

Losing all the heavy Jepp books was a big help for cross continent flying. Mom's teachings on weight savings stays with me today. A mechanic asked if I wanted an engine part painted so it would look better. I thanked him but declined as paint weighs - all those little decisions add up. Most people are astonished that we did 24 days around the world and we shared one medium suitcase for 10 tops, 2 skirts, 2 pair pants and 2 pair of heels. We wore one outfit - it helps to be short. Customs was especially skeptical.

With 10 tanks on the airplane as it sits today, 8 are operational, it is common for us do weight and balance calculations - even though we have 42 years experience with this twin. We just don't take it for granted. Twins are so pitch sensitive at landing CG is a big deal. Don't know if this is the same for singles, but it is why I am cautious about others' questions on carrying more fuel and always encourage CG calculations.

BTW I got a question recently from a high time pilot who had just bought a twin and wanted to get smoother landings. Turns out for his plane, he had to add weight in the back for single pilot operations, the CG was far forward. Not a big problem for me as, on average, women are shorter and lighter than men.

Wherever folks choose to carry the fuel, strongly suggest doing weight and balance departure and landing calculations. The answers may surprise you. It sure surprised us when we did them to determine the order for fuel burn of the 10 plus 11th ferry tank.

Hope this helps strengthen the original poster's knowledge of tip tank considerations.

The Twins stipulate that the gross weight increase is restricted to fuel weight, however, the PA-24-250 does not. Putting tip tanks on automatically bumps the gross weight to 3000, no matter where the weight is.
-Zach

Thank You very much for yours comments, I wasn' sure if the tips Tank was a goodidea, be cause of flying performance, landing, takeoff, etc. Some times You just need to Talk to somebody who has done that modification. Now I have my plane doing paint and is the moment for tips tank!! If someone have any advice I will thank them?

Do it. The added utility, and operational flexibility are worth the price! Best speed mod you can make, you don't have to stop for gas!
Zach