Well, one of the instuctors "re-maidened" my Alpha 60 this afternoon, after I had hardened the servo mount holes and increased the offset in the throttle pushrod to prevent it binding on the engine mount. We also fixed a problem with the way I had the throttle servo reversed that was preventing us from setting up the throttle cut off properly.

Five minutes in the the flight, with an instructor on the sticks, flying straight and level, the firewall separated from the balance of the fuselage. The engine and prop droped like a rock, and the balance of the airframe floated softly down with no further damage. My first thought was that the mount had pulled loose, perhaps do to too little thread lock. Not the case.

We located the upper half of the firewall with the engine and mount still intact on it. It was immediately obfious that there was very little glue on most of the joining surfaces. The bottom half of the firewall, with the front strut was a few yards away, and looked just about the same. Little evidence of glue where there should have been plenty. The prop is trash, as is the muffler and the central screw holding the two pieces together. Other than the tears on the fuselage where the firewall had been, the only other fuselage damage was to the two front sections that partially enclose the engine. Both of them were broken where the firewall had once been, and of course the covering was ripped. Wing, tail, RX, battery and servos all OK. The steering arm was broken where the pushrod pulled out and the two forward pushrods were badly bent when the firewall separated.

I bought the ARF from Hobby Zone, and I'm hoping at this point that they will either send me a new plane, or at least a new fuse and the assorted pushrods, etc that need to be replaced. Not sure what they will do for the engine since I didn't get it from them.

I've emailed them with the story, and can supply digital photos that make it pretty obvious what happened. Now we'll see how their customer service performs.

Stay tuned.

Bob

Too bad, but good that you got pics. Good luck!

It seems every ARF trainer has firewall issues[:@]

Sorry to hear about your plane. Good idea to reinforce the firewalls on ARFS prior to taking to the air.

Mitchell was this story on another topic? If not and i ain't gonna take time to look then someone had about the same experience. That really bites the big one. I read your post on how much trouble you had to begin with and now the motor fall off wow. I had a similar deal a muffler adapt. broke bad casting I guess anyway got hold of company and they sent me a new adapter lol, and a new cowl. I wrote them back thanking them but told them what really was damaged was the fuselage. I still have not heard about that though. Good luck Hobby Zone if anything like Horizon will take care of you.

I assure you, Horizon will make it right.

Next time, and on all subsequent ARF's, you might want to at least pin the firewall. Drill some small holes through the fuse side into the the edge of the firewall, and epoxy some dowells in there. Sand smooth, and re-cover. Helps tramendously. Also, some triangle stock epoxied behind the firewall inside of the tank area works good, and I've also fiberglassed the back of the firewall to the inside of the fuse. All of these methods help hold the firewall together.
There are a couple of areas I always pay attention to on ARFS now..
Firewall, wing joint, tail feathers, and hinges.
I also change the control rods quite often as well.

I was having some problems with throttle linkage/throttle cut off which I had posted here as well, looking for some assistance. I posted to that thread that we'ed solved the problem, but that once in flight I had a disaster, and that I was posting about it in a different thread. You may have seen it there.

I'm on the phone with Horizon/Hanger 9 as I type this, so we'll see how good their customer service really is.

Thanks,
Bob

I just got off the phone with the Horizon/Hanger9 folks and they will replace the entire plane, plus the damaged muffler assuming the digital photos support what I'm saying. So......I'll get the photos this evening, email them and hopefully by tomorrow there will be a replacement on the way. The support tech I spoke to was very helpful and indicated that it didn't need to go beyond him once he got the pics. That reinforces most of the comments I've heard about Horizon's customer support.

And I WILL do some reinforcing on this one as I assemble it.

Bob

Wow, that makes me feel better about ordering my alpha 40. I like to try and keep one brand or main parent company when possible. I have all HPI cars, and all my radios are either JR or Spektrum. Both companies so far have always been johnny on the spot for anything I needed help with or had questions about.

FTFY

list of personal experiences with arfs...

before assembly, epoxy the firewall on both sides. mix epoxy with alcohol and paint inside where the fuel tank goes, as well as the entire engine compartment. (i also paint the servo tray) i try to reglue everthing i can get to with epoxy or ca. recheck aileron torque rods in the wings for slop. i replace All the hardware with 2/56, or 4/40 stuff. i change the fuel tank, and tires. i usually change the landing gear to composite or aluminum. i add the little skid plates to the wing tips and the tail. thankfully the only equipment failure i've had in the last 4 years is the nut behind the sticks (hard to fix, no parts available)

What is it with my ARFs? I've never had to do any reinforcement or repairing on any new ARF. I keep hearing about everything being so fragile but just don't understand. Perhaps I've just had good luck... [sm=confused.gif]

sounds like very good luck. unfortunately i had to learn everything in my previous post the hard way...

While I tend to re-inforce whenever possible, the only real failures I've had have been when I've landed quite hard.

Maybe all too often hard landings are not taken to be such, by the pilots....

( although my Brio 10 has admittedly WEAK gear! )...

I've seen pilots bounce planes so hard that I cringe, and then they act as if this is normal wear and tear.

I guess I end up re-inforcing to prevent their failures?

Vegas, sounds like you you should kite build

theres not enough wood to mount the engine to ...

I never had a problem with my Brio 10 landing gear. Then again, I fly off a smooth paved surface. I agree, some pilots think one or two feet high bounced landings are normal! I'm not saying everybody that has had a problem is a bad pilot, I'm sure there are lemons out there..... I just haven't bought one yet.