Krener

Well, maidened the US 60 yesterday.
Pics speak for themselves.


She flew beautifully for 7 minutes, then I lost elevator.
Tried to put her in as flat as possible but to no avail.
As can be seen in the post crash pics the elevator push rod broke at the thread behind the clevis. I had changed the push rods from the ones I made to Dave Brown items as mine would resonate & flex too much for my liking & the Dave Brown ones seemed fine.
Essentially all I had managed to achieve was instead of the rod flexing, all the vibration was being absorbed by the other components in the rod assembly, & the weakest link failed.

Kinda spewing, 6 months & quite a few dollars down the dunny, not too mention the fibreglass & paint finish that took forever to get right[&o]
Broke the crankcase on the new 75AX dont know if that is worth replacing.
Only the electrical side survived, & the retracts.
Ah well, such is life.

mustangman177

Sorry for your lose dude. Can't imagine there being that much vibration at the aft end like that to break a clevis. I use Great Planes threaded pushrods, so far no problem.

Don't let this discourage you...Get another plane back in the air and enjoy flying !!!!!

Redback

When you Territorians crash you sure make a job of it!

Sorry for your loss

Terry

multicasting

Dude! No Way! I have been watching the build thread all this time. I loved your paint job. You had said the rods were giving you trouble. I do feel your pain. Two weeks ago I maidened my Top Flite P-47 (Painted, not covered) to similar effect. My mistake was forgetting to range check. I fought an inconsistan radio all the way to the ground. Mine will fly again since I only went in at about a 20 degree angle at 1/3 throttle.

A few days earlier while practicing for an airshow,I lost my old faithful Ultra Stick in a lake. I retreived all but the nose with the YS engine on it. Also an unknownradio issue (different system.) At least I got 5 good years out of it.

What are your plans now?

Bob

Korps

Sorry for your loss Krener.

Now get another one and GO GO GO! :P

Krener

Yeah, I was quite impressed by the carnage.
I mounted the engine with the exhaust down with the logic being, if the retacts folded on a landing the exhaust would save most of the underbelly from severe gravel rash.
Unfortunately when she went in, the exhaust hit hard & ripped itself off the crankcase & wiped out the bottom nose section, but not before snapping the engine mounts.
The firewall was still intact, didn't budge an inch

I could rebuild her, would be some serious weight gain (maybe) but the biggest issue is safety.
Underneath all the fibreglass & paint I have no idea how damaged the rest of the structure might be or if it will hold together through high g turns etc. I'm thankfull it went the way it did & not on approach to landing or else she woulda gone into the pits.

Well, onto the next kit I guess (Top Flite P-47), but I think I will get another US.

For those 7 minutes she really looked like a keeper

prgonzalez

Krener,

Sorry for your loss. She was a real beaty.

Now for lesssons learned. Where you using 2-56 rods?

In two occasions I broke 2-56 pushrods at the thread end when using them to create the thread inside a brand new clevis. Now, I use a tap to create the thread in new clevises. The rod go in as smooth as in a regular nut after that.

Recently, I decided to go with carbon rods with titanium ends.

WestCoastFlyer

My Feedback: (1)

Krener, condolences on the loss. Some planes are harder to lose than others, and sometimes there's a sort of grieving process that goes on. Oh well, we have the memories.

Regarding the crash, maybe the clevis pin was tight in the servo arm and it bound up? Was that pushrod flexing at the servo when full up?

Krener

Clevis was loose as a goose (in a good way)

I had placed ball links at the control surface end to remove the chance of binding, and the 2-56 had rolled threads, not cut threads like a die would make.
One thing is for certain, from here on in only 4-40 stuff.
Will have to look into the titanium rod ends also.

Some may say overkill, but until you experiance something like this you just don't know.

qldviking

its always sad to see a plane go in personally I think 2-56 is too light for anything bigger than a 40 size plane. I always step up to 4-40 with 60 and above. I've had similar experiences in the past with 2-56 h'ware breaking on 60 size ands planes and even one of my 40 sized. I thinks that for the sake of a few dollars and grams I'd sooner err on the side of safety. Just a lesson I too learned the hard way

WestCoastFlyer

My Feedback: (1)

I haven't used the light gauge threaded pushrods (I recall some fully threaded) in anything going back 15 years, but I'd never have guessed the stresses would have snapped it, so this is definitely a word to the wise for people reading this thread. I really like the carbon / titanium combo above. I over-engineer, it's part of the deal, and a huge part of what's great about RC.

It's a pity that happened to such a gorgeous airplane.

Alex7403

Sorry for your loss krener,

It seems strange it broke like this maybe there was a defect there, a crack or something like it from bending it.
Anyway at the end of a thread is a weak point.

I'm sorry to say but if it was because of a crack it can happen in 4-40 rods as well.

You are from the US60 club you will build more of them.

Alex

dragonov3

My Feedback: (3)

I lost my bridy air cruiser the identical same way. I had the exact same setup on my elevator push rod. I was at the top of a loop , about 200 feet up when mine gave way. She went in like a lawn dart. Hit so hard it compressed the balsa in the wing as well as shattering every rib, squished tank to about 1/2 its length and destroyed the battery pack. The funny thing is the engine survived, all I needed was a new needle valve assembly.

vmsguy

This has been a tough summer on Ultra Sports... [sm=cry_smile.gif]

Wow.. off the top of my head, RCU members have lost at least four this summer... [:@]

Maybe I should order another kit, before they're out of stock again.... [sm=wink_smile.gif]

prgonzalez

I am building one from scratch (RCM plans) at this time and have two GP kits in my closet.