Originally Posted by zool.on

Hi,

What is the size of the prop bolts? I have installed my second 30 on a pilot yak with a Xoar 19A. The 19A is a lot thinker then the 18X8 I have on my other one and combined with the thickness of the spinner back plate there is not much thread left on the bolts to the hub. I was thinking of getting some longer ones. Or do you think it will be ok as is? All I have is about 4mm

Originally Posted by RTK

If the prop is loose enough to slip you will more than likely shear all bolts and loose the prop, but with a single bolt hub it will only tighten itself until the slipping stops.
Now you tell me which one is better......................

I'm with you RTK. Zool.on, before I ever even started my DLE 30 I switched to the single hole prop adapter rather then drilling all those holes in my prop hub. It makes testing different props much easier without having to worry about drilling every prop you have as well as having to align the M4 bolts in the proper location to index your prop to the compression stroke for starting. The prop shaft is also tapped for a spinner screw. Here is a pic of the single hole prop bolt adapter and a site to purchase from. http://www.valleyviewrc.com/DLE%20Si...%20adapter.htm

Single bolt is the way.... Makes it easy to put my starter to the DL30 for quick easy starts, as mentioned, no drilling props...Center bolt is also tapped for spinner nut.

ValleyView drills em for free... just sayin.

Originally Posted by rcign

Our GT80 race engines turn 12,000...Single bolt prop hubs...No slip...Operative word here is TIGHT...Dead tight..As in you can't turn the wrench any harder...A GOOD prop hub won't strip...
We use a single 3/8-24 grade 8 on our 30+ hp race twin..with two 1/4-20 anti rotation bolts...The bolts sheared once because I forgot to check in between heat races...The 3/8 center bolt just got tighter and kept the prop on...You don't even want a 23 inch carbon prop turning 9000 rpm flying around by it self...

So... your telling me when I use a wood prop, I should continue to crank down until I can't turn anymore, even though I may crack a hub and that is somehow better than mutliple bolts tightened in sequence? No thanks. You are correct, I dont want a 23 inch carbon prop flying around at 9K RPM, therefore, I would have checked my bolts, which you just eluded to was the real problem (operator error) for the shear and had nothing to do with the actual bolts.

Originally Posted by RTK

If the prop is loose enough to slip you will more than likely shear all bolts and loose the prop, but with a single bolt hub it will only tighten itself until the slipping stops.
Now you tell me which one is better......................

\

Mutliple bolts and operators that have enough sense to check them as part of a basic pre-flight day routine.

Originally Posted by 3Dguy

ValleyView drills em for free... just sayin.

yeah this would make swapping props a breeze while figureing out what works best for your needs....

Has anyone tried the DLE30 on a H9 1/4 Scale Cub? If so I would like to know how it performs and how much slaughtering had to be done to the cowl to fit. I have a new Cub and cant figure out what setup to run but want to keep from detroying the cowl.

Originally Posted by Yakster

So... your telling me when I use a wood prop, I should continue to crank down until I can't turn anymore, even though I may crack a hub and that is somehow better than mutliple bolts tightened in sequence? No thanks. You are correct, I dont want a 23 inch carbon prop flying around at 9K RPM, therefore, I would have checked my bolts, which you just eluded to was the real problem (operator error) for the shear and had nothing to do with the actual bolts.

A little common sense here....No one would use a wood prop on a 12,000 rpm race engine...The props are carbon fiber...If anyone can crush a carbon fiber prop and or crack one of my2024 aluminum keyless hubs with any normal wrench I would like to see it...

RCIGN...The only problem is not many reading good advice have any common sense!
Capt,n

Most of the carbon props on the market have a wood hub at the core. That wood's density covers a wide amount of territory The blades are made in two halves and laminated over the wood core. Yes, you can crush the hub of those carbon props, and it has been done many times in my shop. Ever see a carbon prop explode? You don't want to be there and you come to appreciate a prop guard real fast. Those are only 26" to 28" props and I would not want to see anything larger go off like that.

I don't think Mejzlicks are wood, but can't remeber from the last time I drilled one.

Nope. The only other CF prop I have drilled is Xoar and they have an epoxy core. There are many other brands though that TOM is aware of that I have not seen.

I've got a Mejzlik 3 blade sitting on the dyno that should let go any day now. So far Biela, Bolly, and Mejzliks have all let go without favor. They can be crushed, and unequal torque is something they don't like at all. Fuchs has a wood hub also. APC is solid, which I'm guessing a good many racers use.

The multi bolt hubs are now used instead of the previous single bolt arrangements. Lots of props departed using a single bolt. The problem went away with the multi bolt hub.

How did props depart with a single bolt ??