jedijody

My Feedback: (1)

I see no reason the user shouldn't tear it down if he wants to, my customers do it all the time. It's a DLE, if it's defective it will be warrantied and replaced by the factory no questions asked.

Antique

My Feedback: (4)

Razor Hobbies

My Feedback: (50)

Wow im surprised i did not hear that before now that i am at home watching the video on my laptop i can hear clicking / grinding pretty clearly.

Valve floater

Sounds like one of the pistons may be traveling to far out and taping the head slightly?Out of the seated area.Wrong size rod. Head manufactured wrong? Rod bearing failure? Debris at TDC. Thousand things.Please let us know what you or Razor finds.

av8tor1977

My Feedback: (6)

Yeah, I would swear I hear bad sounds on the video for the whole run.

Take it apart and let us know! 8 bolts and you have both cylinders off. Two minutes time if you spend one of those minutes looking for the tool.

Then the mystery will be solved...

AV8TOR

av8tor1977

My Feedback: (6)

Man, I just listened to it again with the sound turned up. The "abnormal" noise is louder than the exhaust at low and mid throttle. I think I can hear some screeching occasionally as well.

AV8TOR

wpmcnamara

My Feedback: (9)

Minor correction in your event sequence, and I am the cause of the error as I made a mistake in my first post. The initial flip in the video was with the choke off. At the starting of the video, I had just had the first pop with the choke on. My mistake. Here is the sequence.

First flip, choke off, engine fires briefly.
Eighteen more flips no fire.
Choke on.
Four flips engine pops on the fourth.
Choke off as Jody says, you here the click. I should note that as I take the choke off, you do see a drop of fuel come from the carb, right about the 00:1:02 mark.
Flip engine fires and runs.

wpm

wpmcnamara

My Feedback: (9)

Of course now I feel like an idiot for not noticing the sound when I started it. [:@]

I'm thinking possible a failure in the rear bearing. Anyway, as I said earlier, I get to go fly today. So, I'll take a look the evening. Thanks to everyone for their input and experience.

wpm

maly43

My Feedback: (39)

I'm no expert call me a dumb a.. if you want but would a ring improperly installed, gap at exhaust port, make the click sound and then fail. Always under the impression to install this way.

BadAzzMaxx

Had something closes to this happen with another 100 cc engine, Not a DLE.

When started it had a loud noise like a rod knocking, I check piston clearance, End ply on rod bearings and wrist pin bearing and all was good.

Finally found it to be a lose prop hub, Hub was tight enough that you could not fell it being lose by just checking it by hand but was lose enough to slip when engine was running.

By the time I figured out what it was it had twisted the crank and destroyed the key way slot in the prop hub.

Milton

maly43

My Feedback: (39)

forgot index pins

brian5

That engine stopped suddenly and slung the prop off. note the bent and sheared bolts. I finnally found a post I can agree with Jodi on.

Mustangman40

My Feedback: (1)

I have a related question..

I am just getting into gas and would like to know, can a carbon fiber prop fly apart like that as well? With what happened to that wood prop, that is some serious danger.. I could see someone getting hurt bad with something like that and it has me wondering if CF is safer?

Tired Old Man

My Feedback: (1)

Happens all the time with 4 stroke glow engines too. The situation is not limited to gas and extends to all engines.

Improperly installed, any prop can fail. The manner is generally dependant on the mode of installation. Carbon props generally require more force to generate explosive failure than wood. Wood is more sensitive to shock damage than carbon, but both go to pieces quickly upon contact with things in their rotation plane. A certain level of knowledge is required of anyone intending to use a propeller of any type. Failing to possess that knowledge can be dangerous for the user and anyone around them, regardless of the propeller composition.

This is why we've been telling people for many, many years not to stand in front of propellers when running up engines. It's why we don't have our planes pointing at nearby spectators when we start engines. It's one reason why you should never tune an engine from in front of it. So don't panic. The danger isn't any greater than what you've been subjecting yourself to for as long as you've been flying already.

Valve floater

That`s some serious force.Let`s you know we are not dealing with play toys. I have never had this happen in all my years of flying gas or glow. Sure ,i have had some 4-strokes kick back and unscrew the prop off. But i never seen anything like this. I don`t want to see this anytime soon.

Razor Hobbies

My Feedback: (50)

Well correction for safety you should never really tune an engine while its running. You should always kill the engine and make your adjustments.

Sure some people do it but its pretty dangerous even for a nitro.

Valve floater

TOM. Do you think this mount is to solid. Not enough movement like mounted to the plane.Not enough give and take for engine vibration? Tore itself apart?

dave pattern

My Feedback: (3)

some where around 2 mins some thing goes from right to left across the camera was it a piece of prop? im not sure.
but definitely just before the prop shreds a piece flew off on the left side. looks like a tip, maybe an inch or two long.
watch it again
i dont have sound right now so i cant hear it but that might help to see the piece fly off(less distraction)
Dave.

Razor Hobbies

My Feedback: (50)

That was not the cause. In the video you can clearly hear something click / grinding internally.

Plenty of people mount there engine test stands to a post.

Razor Hobbies

My Feedback: (50)

And it was a bug flying in front of the camera because it moves left out of frame then back right across the frame. And when you slow it down it looks to have wings so bug.

before anyone beats me to it.

"There a bug in the engine".

LOL

karl hibbs

My Feedback: (6)

From past experience it sounds like a loose prop (clicking noise) with soft Chinese bolts and the prop broke instead of the bolts shearing off. When are you going to take it apart to find out what went on inside.

Tired Old Man

My Feedback: (1)

The mount was and is just fine. In reality it's probabaly a lot better than what you would have had in a plane. The plane would probably had metal standoffs that would have allowed a lot of twisting force to be applied to them since they are unsupported, independant legs. Watch your video again, closely, and look at the twisting forces applied to the engine mounts. Now imagine that same force is applied to 4 independant spacers about 2" long and 1/2" in diameter and you'll quickly understand why I will not use aluminum stand off legs. They become a torque multiplier and are very hard on engine mounts and firewalls.

As for the engine, don't tear it down yet. Pull the spark plugs and turn the engine over. Do you feel any bumping or resistance at top and bottom dead center? If you do at top dead center it's possible the squish band was too small and the piston was bumping the top of the cylinder. One Chinese manufacturer is notorious for this. Not DLE of course. You also have the possibility of foreign material ingested by the engine, essentially creating a piston stop. If the engine had been lying around the bench, carb facing up with the plates open, something could have fallen into the engine by mistake. It's a straight shot to the reeds and they won't stop anything unless it's too large to pass through the openings.

Had the prop been dropped by you or someone else prior to your owning it? Could have had a hairline fracture you didn't see or know about. Those always blow apart. Could have been a simple wood grain separation, but the loose screws absolutely allowed the prop to wobble on the engine hub. This will always destroy a prop in a very short period of time. Screws too loose or tight, when used on an engine tuned so baldly it's experiencing detonation can eat the center out of a prop hub. Wood or carbon. I have several examples of that in the shop.

Over torquing prop screws with a wood prop compresses the hub. Equal torque is no longer possible with a compressed hub, so wobble is pesent to some extent. Screws want to "loosen up" all te time so efforts are made to re-tighten the screws, generating more hub compression. They really didn't loosen, the wood continued to compress under the overtorque. So a few cycles of tightening that wood prop and a longitudinal fracture appears across the prop hub and into the blades.

Had a "small" prop strike? Better look at that prop real close and try a few bending loads to seek out invisible splits. Remove the spinner and prop to inspect the hub too. Guess what happens if a split was there, you missed seeing it, and use the prop again? The video was a great example.

Bottom line on props is to inspect them before you install them, continue to inspect them periodically, and buy an inch pound torque wrench. Then use it every time you install a prop or check the screws. Check the screws frequently. It's not a one time on and forget deal.

Valve floater

Your right TOM. I had my engine kill yesterday from a prop strike.gonna check it now before i fly today.Thanks

jedijody

My Feedback: (1)

All very good information TOM and I agree but in this case it seems clear the engine stopped then the prop exploded. I've seen engines shed props and none of them quit like that, they kept running and suffered no damage if the operator shut them down fast enough.

Why is it I've never heard what an engine sounds like while running with loose propeller bolts,.... no, I don't think I'll experiment with that one. [8D]

captinjohn

If the prop just broke on its own or because of loose bolts the engine most likelywould haverevved up untill the ignition rev limit was reached or reed valve float occured. Quik shutdown...most times no engine damage. Maybe there was a extra screw loose inside! Capt,n