---------------------------------------------------------- Tailwind-List Digest Archive --- Total Messages Posted Tue 01/11/05: 2 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 12:51 AM - Re: Titanium Landing Gear (Fred Weaver) 2. 10:22 AM - Titanium (Jim & Betty) ________________________________ Message 1 _____________________________________ Time: 12:51:15 AM PST US From: "Fred Weaver" Subject: Re: Tailwind-List: Titanium Landing Gear --> Tailwind-List message posted by: "Fred Weaver" Lots of luck Chuck... You have been warned. 10-12 pounds is nothing compared to a wobbly feelin' gear. And yes, I also have a Harmon Rocket. It has Titanium gear legs. I don't know the alloy as I write this. BUT, the gear leg is much larger in diameter than a Tailwind gear. And yes, again to the location of the axles. They should be almost directly under the Leading Edge when the airplane is bubble level. Weav ----- Original Message ----- From: Subject: Re: Tailwind-List: Titanium Landing Gear > --> Tailwind-List message posted by: Rcaprd@aol.com > > Thank you all for your responses. It is what makes this list so valuable. > Rich E. - weight savings is what I'm after. If I can save 10 to 12 lbs., > then it will be worth it...given the shimmy tendency is eliminated. Even if > it costs me some extra bucks, it pays dividends with every flight. > Bob T. - I was hoping someone had some input on the machining of > Titanium. Do you know what alloy you were working with ? There is quite a few > different alloys. Two of them are 6AL-4V, and 3AI-2.5V. The 6AL-4V is what > Titanium Joe has in 1.375" round solid. He also has it in the diameter for the tail > wheel. The 3AI-2.5V is what the seamless tubing is. The first number in > these designators, is the percent of Aluminum is in the alloy - the second number > represents the percent of Vandadium - the remainder is Titanium. Another > designator is C.P., which stands for Commercially Pure Titanium (99.9% Titanium). > Forest L. - If Steve Wittman was using Titanium, then there must be > something to be had with it...like his Scimitar Props !! > Fred W. - I would like to talk with Harmon Lange on this subject. Is his > number still 503-397-1478 ? That's what is listed in T.T. Do you have a > Harmon Rocket ? What type gear is on the Rocket ? How can I contact John > Harmon ? As far as removing weight up front on the Tailwind, well, I have added 2" > at station 0, in my fuselage jig. However, this brings up another ripple > effect. Most are in agreement that the W10 axles should be 8" to 8 1/2" behind > the firewall. The thing is, the axles should be placed in relation to the > leading edge of the wing. The plans view, show the axles parallel with the > leading edge. Therefore, should I keep this location, by sweeping the axle > alignment back the additional 2" that I added at the firewall ? As far as the > springiness, hickory, wraped in Kevlar / epoxy, could be used to fair in the round > legs, and also serve to damp out the harmonics. > Mike M. - Tapered gear legs would be preferred for aerodynamic reasons, > as well as a way to set the placement of the flex, and the spring rate. > Hjelle - Could that shimmy have been caused by an out of balance wheel / > tire ? It seems this is the primary cause of gear shimmy on the Tailwind > taper leg gear. Is there any way you, or anyone else, could come up with the > precise dimensions of that gear ? > Bob T. - The weight comparison is one of the things I was looking for. > Joe Maj. - The modulus of elasticity is one of the characteristics that I > could not find anywhere. Where did you get these figures ? This is the > reason the dimensions could not be the same as for the 6150 or 4340 steel gear. > What is the difference between the modulus of elasticity of 6150 and 4340 ? I > believe the meaning of which is the point where a material can be bent, and > will return to it's original form. If steel is bent, and never exceeds it's > modulus of elasticity, it will not fatigue. Aluminum, however, will fatigue in > short order, even when it doesn't exceed it's modulus of elasticity. How does > Titanium, in its various alloys, perform in this manner ? > > Chuck G. > In the Research Mode !! > > ________________________________ Message 2 _____________________________________ Time: 10:22:55 AM PST US From: "Jim & Betty" Subject: Tailwind-List: Titanium When machining titanium use slow speed and slow feeds. Once the drill, end mill or bit starts cutting keep it cutting. Use lots of coolant in all machining processes. I mean use lots of coolant and flood that cutting area. The machining process can generate a lot of heat. Keep the machining area or sworf picked up after each process. Keep a bucket of sand on hand for safety. If titanium catches on fire do not I repeat do not throw water on the. Dump the sand on it. It acts in a similar fashion to magnesium. Someone else may want to verify this but it is my understanding that titanium has a much shorter lifecycle than steel alloys.