Warning: RCGF 45 Owners!
 

Heads up for owners of the RCGF 45 engine. Was running my engine on the test stand the other day when the prop hub sheared off and hurled the prop over my house from the back yard into the front yard. Glad I was standing behind the engine like I was supposed to.
This is a dangerous design with the hub wall being so thin. Even if it were 6061 it would be dangerous.
I am going to have a custom hub made to replace this and I recommend you do the same.
The reason is pretty obvious in the photos below.

RE: Warning: RCGF 45 Owners!
 

Wow!!

RE: Warning: RCGF 45 Owners!
 

Nice! The hub should not have been hollow, and 6061 is too soft. Wait till you try to get it covered under any warranty policies....

RE: Warning: RCGF 45 Owners!
 

I am going to have a custom heavy duty one made.
What do you suggest 7075?

RE: Warning: RCGF 45 Owners!
 

I am glade you was not hurt. Had you or anyone been in front of the engine....it would have been very bad for sure. I just went to a couple of big AMA chartered fly-in,s last weekend and noticed many of the guys would stand right in front when reving the engine up after starting. Many guys do this....WHEN IS THE AMA GOING TO GET AFTER THE CLUBS WHErE PEOPLE DO THIS? It is the most stupid thing done & can be stoped. Capt,n
http://www.rcuniverse.com/forum/js/f...n/rolleyes.gifhttp://www.rcuniverse.com/forum/js/f...n/rolleyes.gif

RE: Warning: RCGF 45 Owners!
 

100% right Cap'n
I have seen a few of these do this (a couple of others have posted on the adapter breaking elsewhere) - once you see it happen, you NEVER stand in front of a revving engine again

Sure am glad nobody was hurt.

RE: Warning: RCGF 45 Owners!
 

In the first photo, it looks like a half a hole in the hub right at the break line. Was this for the sensor magnet? It looks like it
may have contributed to the failure! Also, it is hard to see, but is there a generous fillet at the juncture of the hub sleeve and the hub washe (where it broke)? A sharp juncture here would cause a stress concentration and early failure. The failure looks to me like a design fault that should subject the hubs to be recalled and replaced with a STRONGER HUB!


Richard

RE: Warning: RCGF 45 Owners!
 

The sensor magnet wasn't effected. If you look at the photo you can see another ring below the broken hub flange. That is where the magnet is installed.
There is no fillet at the juncture of the hub shaft and flange. It is almost a clean break there too.

RE: Warning: RCGF 45 Owners!
 

6061 is just fine if the hub was indeed 6061..Looks cast and machined to me....There are hundreds of engines out there with 6061 hubs made just like that...You can't cast a hub, then machine it to look like billet, without having problems...

RE: Warning: RCGF 45 Owners!
 

I agree, the break looks like cast aluminum. 6061 is what I machine all my conversion hubs out of, I always found it more than adequate.

RE: Warning: RCGF 45 Owners!
 

Cast and machined to look like billet and the walls this thin. Scary !

RE: Warning: RCGF 45 Owners!
 

I'm sure the production cost was low enough to meet planned cost criteria....

Antique,
My "soft" reference to 6061 was related to a hollow hub, not a solid one.

RE: Warning: RCGF 45 Owners!
 

I don't know US law at all but I do wonder what would happen if there was a fatality as a consequence of this and they could bring out some "product specialist" to state that it was due to poor materials that were "unfit for purpose".
Who would carry the responsibility?
Hardly anyone would attempt to have a go at the factory (in China)?
Would it be the retailer? Distributor?

Here in Australia, people would head straight for the importer (Distributor) with a lawsuit. Our Fair Trading people would without doubt instigate a forced recall.
Lots of lawyers would get even fatter than they are already

RE: Warning: RCGF 45 Owners!
 

Yikes! I never even considered this might be cast. I didn't even give that a thought because I couldn't imagine anyone would make a hub out of cast aluminum. I don't even want to think about cast aluminum from some of the China foundries. We have enough trouble with some of the casting we still get from American foundries.

I am going to use 6061 because the wall thickness around the crank shaft bolt will be much thicker than the original. We have 6061 laying around everywhere here at work.

apalsson, you can bet the same thing would have happened here in the states with lawyers and such.

RE: Warning: RCGF 45 Owners!
 

Even worse, some of the Chinese hubs were cast, then used a very large (UNNECESSARY) keyway..When the cast hub was tightened the hub split at the keyway, almost every time.....Without the keyway the hubs MIGHT have survived....

RE: Warning: RCGF 45 Owners!
 

I just purchased the 26CC version...  Anyone know if this is the same, or could be the same the problem?

bob

RE: Warning: RCGF 45 Owners!
 

Bob,

I don't kow the other ones but if they are casting the hubs for one size, it makes no sense to assume they are machining the others.

RE: Warning: RCGF 45 Owners!
 

it that a new one that u jst got ?? i got one from henry in 09 and got quite a few flights on it... if not new,,was it ever involved in a crash or prop strike..i'm gonna chk mine out tomarrow though..thanks for the heads up... tim

RE: Warning: RCGF 45 Owners!
 

I don't know about the one you have since RCGF doesn't seem to make the same engine twice, but the one I worked with chucked the whole front of the engine in flight when the woodruff key ate it's way through the key slot. Since RCGF used an incorrectly matched crank and hub taper fit there was no way the two parts were going to stay together.

If your engine breaks I hope you got it from a reputable dealer because RCGF might deny warranty work for individual users. In the case of the 26 I had experience with they denied it was their engine. Since they put the serial numbers on the ignitions and not the engines themselves it becomes real easy to do that. One could almost think that was the intent behind not numbering their machine products. If they sold a 200cc 4 cylinder for $10.00 I could not be enticed to purchase another RCGF engine. Not even if they gave them away. I've had a pair of 100 twins and you could not interchange any parts between them. The machine tolerances were that much different.

RE: Warning: RCGF 45 Owners!
 

I bought it from a guy here on RCU but it was brand new in the box and it came from RC Aero.

RE: Warning: RCGF 45 Owners!
 

[sm=47_47.gif][sm=bananahead.gif]:) < Me

RE: Warning: RCGF 45 Owners!
 

Blake

I am Gregg with Bp Hobbies. <div><font face="Calibri">"We are sorry to hear about the prop hub.  This looks like an older style of hub that was sold to the previous distributor of the engines.  RCGF has made many improvements over the years.  They do not sit still on a product.  We have found them attentive and supportive to all of our customers and to us.  Even though we were not involved with the sale of the engine, if you send the entire engine back to BP Hobbies, we will replace the engine at half price.  Please reply via private message with your name and address so we can confirm it was you when we receive it."  
</font></div><div><font face="Calibri"></font>

Gregg
Bp Hobbies </div>

RE: Warning: RCGF 45 Owners!
 

help.... is there any way of just looking @ this hub and telling if it machined or cast ???? hope the pic's worked :)

RE: Warning: RCGF 45 Owners!
 

That is a cast hub for it has minute occlusions or porosity that 6061 would not have

RE: Warning: RCGF 45 Owners!
 

oh boy..... thanx w8ye... guess i should try to find someone that can machine me one :( b4 someone dies [X(]