THE NEW MT 57CC ENGINE

[Tired Old Man]

I have to admit that a single bolt and the average wood prop don't get along very well anymore. Too bad all the manufacturers now go with soft woods for propellers. The good stuff must cost too much.

If your using a carbon or plastic compound propeller there's no issue with a single bolt hub at all. There's quite a few of them flying for many hours at a time everyday with no slippage, and pre-flights day after day indicate there wasn't any slippage from flight to flight.

Point was, when multi bolt hubs first appeared on 50cc singles there was absolutely no need for them. It was some pretty good marketing strategy to make people believe that what they had was not as good as it should have been, and went on to sell a lot of engines with information based on a lie. Same thing with "auto advance" ignitions over mechanical advance. People are generally kind of dumb and will buy into anything if it's presented nice and slick, even when it's wrong.

If a prop hub was equipped with two anti rotation pins that were long enough to make it about half way through the prop you can still use a single bolt hub on a wood prop made of today's softwoods, using the same torque as you would with a multi bolt. How do I know?? I do this on my own stuff and have a 105cc engine set up this way. The racers flying along at a sedate 220 plus miles an hour with engines over 200cc's are doing the same thing. The process of using anti rotation pins would be less time and work for the manufacturers and make life a lot easier for the users.

jrjohn,

You're the one that doesn't think Brillelli should remain in business becase he uses a single bolt hub? Better have a talk with Echo, Poulan, Toro, Yardman, and just about every other saw and mower engine maker out there. Based upon your position on mulit bolt hubs all of them should be closed up and run out of town.

[jrjohn]

	Quote: Originally Posted by Pat Roy
	I have to admit that a single bolt and the average wood prop don't get along very well anymore. Too bad all the manufacturers now go with soft woods for propellers. The good stuff must cost too much. If your using a carbon or plastic compound propeller there's no issue with a single bolt hub at all. There's quite a few of them flying for many hours at a time everyday with no slippage, and pre-flights day after day indicate there wasn't any slippage from flight to flight. Point was, when multi bolt hubs first appeared on 50cc singles there was absolutely no need for them. It was some pretty good marketing strategy to make people believe that what they had was not as good as it should have been, and went on to sell a lot of engines with information based on a lie. Same thing with "auto advance" ignitions over mechanical advance. People are generally kind of dumb and will buy into anything if it's presented nice and slick, even when it's wrong. If a prop hub was equipped with two anti rotation pins that were long enough to make it about half way through the prop you can still use a single bolt hub on a wood prop made of today's softwoods, using the same torque as you would with a multi bolt. How do I know?? I do this on my own stuff and have a 105cc engine set up this way. The racers flying along at a sedate 220 plus miles an hour with engines over 200cc's are doing the same thing. The process of using anti rotation pins would be less time and work for the manufacturers and make life a lot easier for the users. jrjohn, You're the one that doesn't think Brillelli should remain in business becase he uses a single bolt hub? Better have a talk with Echo, Poulan, Toro, Yardman, and just about every other saw and mower engine maker out there. Based upon your position on mulit bolt hubs all of them should be closed up and run out of town.

Pat, whats your point, I agreed with you about the single bolt hub being a weak link. you seem to be trying to straddle a fence here.

[jrjohn]

Pat, could you please copy and paste my words where I said I didn't think the guy should remain in business. I don't remember saying that.

[RTK]

No reason for a 50cc class engine to have a multi-bolt hub. On my BME 115's I use the center nut and (two) other bolts, that's it. Haven't had a problem with any of them yet.

I really hate tightening and checking all those bolts so they don't shear.
On my 3W's the factory bolts are so soft they bugger up very quickly, one call to Mc Masters Carr and that problem went away.

[sinergy]

	Quote: Originally Posted by jrjohn
	200 bucks cheaper than the Brillelli, and not a chainsaw conversion, 6 bolt prop hub so your prop won't slip. Say goodnite to Brillelli

I think that about covers it

[jrjohn]

	Quote: Originally Posted by sinergy
	I think that about covers it

i could not agree with you more, it doesn't look good for them

[wildhare]

I've used all different types of prop hubs, from the single bolt of the Brison to the BME's single with two studs to the DA andf 3W 4 and 6 bolt hub to the ZDZ/MT57 style with a center bolt plus 6 4mm bolts.

The single bolt hub will work fine on most 50cc size, but you have to be careful about tightening it. I've had props slip on my BME-102, at that size a single bolt is really not adequate.

Single bolt plus a ring of bolts like the ZDZ and MVVS uses seems unnecessarily complex and I don't like the 4mm screws, they seem inadequate while at the same time being unnecessary, if you can reconcile that statement.

I prefer a simple multi-bolt 4 or 6 bolt hub like the DA-50 or DA-100. The 10-32 or 5mm bolts use the same wrench as all the other bolts on the engine, so only 1 tool is required to do any sort of service, and it's just simple and very reliable.

Maybe it's because this is what I have become accustomed to, I work with these things constantly. I keep a power driver with a bit for this size screw, I can pull a prop off in about 5 seconds and as I said, it's very trouble free.

TF

[Tired Old Man]

Post #12: "Say goodnite to Brillelli"

Admittedly I took some license with that but the quote could be read that way.

I won't even begin to argue a $200.00 price difference. That wins out every time if all else is equal.

Just as an example, if you had a BME 115 you use the center bolt for primary clamping force and only need to use two of the six outer bolt holes for anti slip purposes. They only need to be snug enough not to back out. The point is that multi bolt hubs are not necessary for secure propellers. The same applies to any other engine that uses a 3/8"-10mm threaded center shaft and outer bolt holes to secure props.

[joe barrington]

	Quote: Originally Posted by sinergy
	Pat that is a good point... I have never had a single bolt slip a prop.. guess I have more strength than an 8 yr old As far as the 24" prop needed for an EF Yak that in itself is funny... there is a few hundred out there flying just fine on 22x8s and 23x8s. Keep digging that hole... it's funny to watch.

Dont really know your reason for thinking its funny that the MT57 loves a bigger prop on the EF 88 Yak,especially when u got so upset for someone mentioning Breilli might be dead.Its true alot is down to personal prefernce and style of flying.Being that the EF Yak is the biggest in its 50cc class why would you think a bigger prop is laughable.If you want 8000rpm with less thrust,more noise running a 22x8,trying to haul a big draggy airframe around.Be my guest and go cook that engine.No.If the Brielli is unable to turn such prop sizes with the same authority as the MT,i would agree,use a 22 or 23x8.
Its down to throttle control and the MT throttles well,if youre after full on full stick speed.Get an Extra.

If you go back to page 1 of this thread,you'll see the video and tach readings of the first UK flight with this engine,on a 24x8.The video speaks for itself and certainly leaves no hole for me to go bury myself in

[sinergy]

Joe: The comment was not directed at you at all.. sorry for the confusion.

jrjohn has been a long time basher of Brillelli and the EF 88" Yak.. as you can see he has taken a stab at Brillelli 2 or 3 times in this thread. For him to say that now he can actually fly his EF Yak because of the 24" prop was funny to me. I was just saying there are many flying fine with a smaller prop.

The B60 can turn a 24" prop as well.. I can't recall #s off the top of my head but mid 6k comes to mind. To say "goodbye" to Brillelli because of $165 price difference is rediculous. There are many who shop on price.. pick a chinese engine thread and read it... Brillelli didn't have any of those customers to begin with.

Either way I have been watching threads on this engine because I am curious as are many.. I think they are pretty close in power. Ralph thinks these are going to beat his G-62.. the B60 has an edge over that so it's going to be close.

One thing though... you don't see me bashing. It looks to me like it might be the first engine Larry has taken on that he should be really proud of.

[Al Lewis]

Sorry, I thought this was the new 57cc Engine thread. I guess all of the down time waiting for Ralph to get his engine and give us some real numbers is getting to folks. I've seen two sets of numbers, supposedly from this engine and neither were particularly impressive. I'm not sure which is right so I'll wait for Ralph, or Pat, or someone else I know and trust to tell me what it's doing with what prop. Let's be honest about the 6 bolt pattern on the prop hubs. You guys just like them because they look more like a real plane. Personally I love a good center bolt with two anti-rotation bolts, just in case. Seems some of the manufacturers have taken to drilling and tapping stock bolt heads for the M5X.08 center bolt for the spinner. Not the best of ideas when you check the major diameter of the spinner bolt against the minor diameter of the prop bolt and see what's left holding your prop on and handling that torque so I guess in lieu a four bolt pattern with a center hub is nice.

[jrjohn]

	Quote: Originally Posted by Pat Roy
	Post #12: "Say goodnite to Brillelli" Admittedly I took some license with that but the quote could be read that way. I won't even begin to argue a $200.00 price difference. That wins out every time if all else is equal. Just as an example, if you had a BME 115 you use the center bolt for primary clamping force and only need to use two of the six outer bolt holes for anti slip purposes. They only need to be snug enough not to back out. The point is that multi bolt hubs are not necessary for secure propellers. The same applies to any other engine that uses a 3/8"-10mm threaded center shaft and outer bolt holes to secure props.

Pat, I believe we are on the same page. I agree that multi bolt hubs are not necessary for propeller retention. 6 bolts is overkill in my book, if it was me building the engine I'd use 4 and in the same pattern as the DL/DA-50 The nice thing on this engine is that you can use just the center bolt, 3 bolts+ the center, 6 bolts with or w/o the center bolt. Lots of choices. I have seen a lot of single bolted props slip and sustain serious damage from crushing when tightened in an attempt to eliminate the problem.

My "goodnite" comment was not intended in any way to suggest somebody should not be in business, as a matter of fact I think they should do everything they can to stay in business so they can service their engines. Can you imagine what it would be like trying to find parts for one of these engines if you didn't have a list of the different chainsaws that the parts came from? not to mention the custom parts built on a CNC, where would you get those parts, it would be a nightmare.

The chainsaw conversion guys have definatly played an important role in RC Gas history. I believe it is just that, "history" When I said "goodnite" I was really just making a prediction with no time frame. Please understand, my prediction is just that, a prediction. I don't shape or change the future. It's just an opinion.

Here it is, I believe it will be very difficult for the conversion guys to compete with the purpose built engines coming out of China. Heck, it's going to put enormous preasure on the big name purpose built engine builders like DA, 3W, and ZDZ.

It didn't take long for the Chineese to produce quality, it will only get better. Take a look at the DL-50, it put a huge dent in the 50cc market. I see DL will be coming out with their 100cc twin soon. If it's anything like their 50cc, it will be another shot to the heart. How many ARF's are built in this country? Even Carden, the last company you would expect to offer an ARF (I assume made in China) now has one.

In the end, it's all good for us, the end user, quality products at reasonable prices.