[bbbair]

OK Guys;
I guess it had to happen (eventually)… I pranged by Extra 300 a couple of weeks ago.

I was having the first flight of the season with her and it was going along wonderfully! Five minutes into the flight – the engine lost power and began to faulter… I was out of position for a dead stick but I did what I could to bring her back. I ended up being too high on a short runway and was heading for a fence, so I put her down a tad heavy…

The landing took off the Landing Gear … more to the point; the landing tore out the bottom of the Fuse WITH The Landing Gear! It seems that the designer liked to use steel bolts (10-32) with ‘T’ nuts instead of Nylon bolts into Plywood.

THAT would have been OK; but with the weight of the Engine dropping so hard, that the Engine Box broke off of the Fuse…

Hey! It landed heavy… BUT NOT THAT HEAVY!

So I started looking at the construction – the Engine Box was made up of 1/8” LIGHT Ply laminated with 1/8 LIGHT Ply, the Fire Wall was three pieces of Laminated LIGHT Ply! As described in the instruction manual!
I am starting to lose my faith in these Kit designers!

In a perfect world the light ply is great! When laminated PROPERLY it is very strong – but I don’t live in a perfect world and I don’t know how well the lamination was done…

So now I am REBUILDING my Engine Box – With ¼” Birch Plywood. My nose weight is about to go UP! And I Do Not Care…

For the extra 1-2 ounces in the nose … I can live with it!

The design of the plane is EXCELLENT – the front end… not so much.

The Landing Gear plate has been removed and a new one cut and fit – I’ll glue it in place once I’m done with the Engine Box.

I am busy cutting out pieces to make a new firewall and the Engine Box sides, they’ll be fitting inside of the existing Engine Box and adding to the strength, then there is drilling and pinning of the pieces.

The Big problem will be to rebuild the damage to the fiberglass cowl – it will be a PAIN – but I can do it.

Once all of that is done – I get to reinstall all of the plumbing and hardware and then see how well it balances.
My season of Repairing just started a little bit early…

Of course I still have ONE BIG concern – the engine.
Why did it fail after 5 minutes?

The engine is a DA 50R and it has worked flawlessly for the last two years – the only thing that I changed from last year was the gas. Based on the reading that I have done on RCC I changed from regular gas to ‘Shell High Octane’ mixed up 50:1 blend and went out to the field.

The engine started up after two or three flips and idled nicely… The take off and flight were going smoothly until the engine coughed and lost power, it continued to turn over but JUST.

Once home I took the engine off of the mount and looked at the Carburetor filters – NOTHING. At this point I am guessing that the engine was running HOT with the High Octane fuel (I didn’t think to retune it) and overheated. At this point in time, I’m planning on reverting to my regular gas and increasing the oil mixture back to a brake-in level (32:1) it’ll be messy but it should work. Does anyone else have any other ideas?

Hopefully, I will be able to get the Extra back in the air by July – it depends on my ‘Honey Do List’…

[aceplant00]

was it running last year on 50-1 mix? Or did you jump to 50-1 without re adjustng the needles.

[bbbair]

I moved to the New Fuel without adjusting the needles - I know- I sinned.

[-Rick-]

Thanks for the timely post as far as gas, I was about to change to "hi-test" and just go fly it! Guess I better check it first!!

[HAL9KPCM]

Well, on a positive note, it looks like you have a good rebuild coming along, stronger than before.

[Billpilotca]

Originally Posted by bbbair

I moved to the New Fuel without adjusting the needles - I know- I sinned.

Well Rob - you are not the first to dork an airplane. Its only wood, and the nice thing is that your repair will be stronger than the original. I have replaced a few ARF gear plates and firewalls myself (i.e. I have dorked a few myself !). The wood I use is always much better than the cheap ply they come with.

I would try your original mix and see how the engine responds. But the DA50 should run fine on the Shell premium with a little needle tweak to richen it a bit.

[tech8]

I would check the lines in the tank just to be safe. Not sure if the ethanol in the fuel these days is to blame but the Tygon lines in my tanks are rock hard after one winter now. Once the fuel gets below half tank the stiff klunk line does not allow the klunk to stay submersed in the fuel.

Good luck on the re build

[DannoH]

Not the Midwest! I am hoping to see it fly on June 13-14th!

[bhughes]

If you were 32-1 then 50 to one yes you should have richend it. There's also ign issues ,batt issues, fouled plug , engine internals . Crappy part of our hobby everything is running so good then this happens. Two weeks ago I was having a blast with my aj slick then I lost a wheel second flight lol. She nosed up on landing and the motor and fire wall got ripped off damit

[Flypaper]

These are relatively low compression engines and have no reason to use hightest. It burns at a slower rate to keep the high compression engines from detonating.
There is not enough alcohol in the low test to cause problems.
The Tygon is not as good as it was cranked up to be. One of the problems, as you found out, was to harden up in a short time. Go to your local small motor or snowmobile dealer and get some clear primer line. I used to run a small motor shop and ran into this stuff and used to buy it by the 50 ft. roll.