Thanks Bryan Cobb!!

MH1FLYER

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Brian thanks for doing my line drawing for me for our new Logo. I owe you one. Here's a peek. Once again thank you!!! Let me know how you want your more flexes configured. Are you still going you use two sets??? I don't think its needed, but I love it, and think it would be even better in the long run.
 

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bryancobb

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A Little later

A Little later

Brian thanks for doing my line drawing for me for our new Logo. I owe you one. Here's a peek. Once again thank you!!! Let me know how you want your more flexes configured. Are you still going you use two sets??? I don't think its needed, but I love it, and think it would be even better in the long run.

You're welcome, John. That was not much work and not near enough to pay for two flex-joints. Let's wait awhile till you get deeper into the trailer thingy, and we'll be approaching tit-4-tat.

Be pondering this thought. I'd really like the front part only (that bolts on the pinion) to be steel, since it maintains the preload on the bearings and it gets hammered pretty hard by the drive key. The combustion impulses are transmitted right through that cog-belt and upper pulley, and all that force is hammering on the drive side of that little square key. I don't think aluminum is a good choice to carry 80 hodersepower especially since only half the area of one face of the key is bearing on the inside wall of the keyway you cut into the part, and for less than half its length. Only 0.11 sq. in. !!

I would only be comfortable with aluminum on that front piece, if you had a couple a hundred hours on yours with it being removed at 25, 50, 75, 100, 150, and 200 hours, and inspected/photographed with a 10x glass to see if there's any evidence that 0.11 sq. in. area is/is not adequate for the load.
Aluminum is fine for the other half of the flex joint. It doesn't get "jack-hammered."

So my final configuration will be...(1) One steel pinion output flange 4140 CrMo, Mcmaster has it in 3" dia. x 1 1/2" length for about $15. (2) Three aluminum female drive flanges done your usual way. All holes for 1/4" bolts need to be a few thou' undersize so I can "gang ream" the hole for alignment. Then I will oil the bolt shanks and press them in with a slight interference fit. I'll have to look but the two bolt holes in each of those three flanges, where the bolts go through the aluminum tube MAY need to be "clocked" a certain way so the moments of inertia have a dampening effect. I'll send you an accurate drawing before we get to that point. I already have one Morflex 302 with a hole in the center (picture below), so I'll only need one more. I do not need any hardware.

Gimme some "seeds" to plant on your trailer so I can be developing ideas.


 
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Hawk

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"I don't think aluminum is a good choice to carry 80 hodersepower"

Bryan, What in the world is a "hodersepower"???? And why would you believe there is 80hp going through the coupler??

Cheers,
Rick
 

bryancobb

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Hodersepower is short for "Hot Rodder's Horsepower." I cannot believe you've never heard that.


The 80 HP "THUMPS" WILL be hammering on it. If it were smooth power from an electric motor, it would only be 10 or so, or if there was an elastomeric something between the big cog and that key, it would be OK. In any event, I want steel on the front one.
 

MH1FLYER

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Brian,
Cogged belts or any belts do not transfer shock load. Just wondering what your thinking their?? The only thing that the front moreflex has to do with is, preload on the pinion its self, and the torque of the tail shaft which at worst case scenario 30 HODERSEPOWER max on the front aluminum moreflex. I have 124.3 hrs with the new aluminum coupler now with no problems.
 

bryancobb

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...I have 124.3 hrs with the new aluminum coupler now with no problems...

Yep! And it has not been off and been inspected either! Do you have cracks or smushing in the key way? Helicopters have cracks show up all over them.


I want a steel one on the front. I will wind up with a steel one on the front, somehow.

When you sent me that JPG of your MH2 and asked me to do A, B, & C, I didn't ask why. I just did what you asked. I didn't say "Why don't you do D?" I just did what you asked. I didn't say "It would look better if you..." I just did what you asked in hope that I would get what I wanted out of the deal. :)

My Brantly had a steel one. Robinsons have steel ones. My Mini-500 came with a steel one and I want a steel one.



I remember when we were trying to convince Fetters that the frame cracks were because of frame tube flexing and NOT because of poorly balanced rotors. He was always right. We were always full-o-$#!+. Only after the frame cracked on their perfectly-balanced factory demonstrator did he go down the path we were suggesting...The mast support tree, and rubber mounted gearbox. I don't think a frame has cracked since. Dealing with you right now feels like "déjà-vu all over again" as Bear Bryant would say.

I am excited to help you doll up your trailer into something you and I both will be proud of. I am also excited that you have the resources to help me get my T/R drive system exactly like I want it without shucking out any money! Now let's get-r-done without any daggers being lobbed at each other.
 
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bryancobb

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36 36 36

36 36 36

...Cogged belts...do not transfer shock load....

John,
Our 50mm wide cogbelts have 36 Kevlar cords that each have 4 strands, scientifically twisted in alternating directionsl so as to make the belt track properly on the pulleys.



Each of the 4 strands of Kevlar in each cord is very close in diameter to these things we used on our flight controls on large R/C airplanes. Most of us on this forum have probably held this cord in our hands. It doesn't stretch AT ALL! Now imagine 144 strands like this in a 2" wide flat belt. Can you honestly tell me you think this belt has the slightest amount of shock absorbing capability? Noooo! I shredded one in my old Mini once. It started at 100' AGL. Sounded like a machine gun as the shreds slapped the fiberglass fuselage. When I shut down and looked, I had pulled pitch and cushioned my setdown with only 1/4" (12 strands/3 cords) of the belt flying the helicopter. VERY STRONG BELT! I'll bet my life on it!




If you read the same Gates literature I have read, you will see that for all practical purposes, our belt transfers every tiny little impulse at 98% efficiency, just like these swinging steel balls do.

 
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eddie

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the cracks on the big helio is a hoot,but you can only look for so long and then you go

into big crack overload.


best regards,eddie.....
 

bryancobb

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the cracks on the big helio is a hoot,but you can only look for so long and then you go

into big crack overload.


best regards,eddie.....

:first: Just trying to keep everything full of humor.
 
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