Gear mesh problem ?

[chad289]

I crashed my E5 a week ago and just got the parts in for the rebuild.  The damage report was as follows, broken teeth on the 52 tooth tail drive gear, both crown gears in the transmission, sheered the jesus bolt that runs through the auto hub assembly,  bent tail boom, and cracked front battery tray as well as a cracked main frame half.   So I got to rebuilding last night and everything was going well,  I got the crown gears replaced in the transmission and the new battery tray put in.  However, when I went to get the transmission block put back in and  place the other side of the main frame back on I cant get the holes to line up with the transmission block without there being alot of tension in the gear mesh between the 52 tooth drive gear and the 13 tooth spur gear (by a lot I mean the head will not rotate freely and I can feel each gear tooth "bump" as it enters the gear mesh).  If I remove all the screws from the transmission block I can get a great mesh but the holes in the posts are about half blocked at the back end of the adjustable slot the screws go through. 

I for the life of me cant find anything else that was bent or out of alignment, minus the transmission block every thing else lines up perfectly with the hole in the new side plate, and the main spins like a top without the transmission in place. 

My simple solution would be to simply elongate the holes a little bit to accommodate the the position it need to be in.  Before I did that I just wanted to come to the forum and make sure I wasn't missing something more critical.   Any thoughts?

Oh and before I forget, lesson learned.... Dont forget to locktite or check the screws that hold the horn to the servo because one of those coming loose can will lead to a crash

[Chris Sexton]

You sure you got a 52 tooth spur and not a 54 by mistake?

[Mike Spano]

hey chad, I have had this same problem. going from one large spur gear to the next, the first one fit just fine, the second one did not. I even counted the teeth to be sure something wasn't off....

this has happened on my E7 as well....

first thing to check is count the teeth on each gear and insure you are working with the correct gear ratio. check the manual to be sure you are mating the correct spur gears together.

if you are indeed working with the correct gears....simply put, I just use a jewelers file and elongate the trans holes a tad. not much, it doesn't take near as much as you would think....maybe 4 stroked with a jewelers file in each hole...just be very sure you go straight back and not at an angle. do not use a dremel tool...way too much...

I first ran into this on my E7 when I installed the TT conversion kit.

[chad289]

Thanks guys for the input, one of the reasons I love this forum is the help everyone is willing to offer to help guys get through hick-ups quickly.  There is nothing worse that going to a forum to get help and two days later seeing it has 500 views and no replies.   Chris that is exactly what happened, I ran home and counted the teeth and it is a 54 tooth gear, the packing slip and invoice were right, the part was wrong.  Now the debate begins of should I get the correct 52T gear or order a 12T small spur gear for the tail ratio increase.   Ive been running in the slower side with my HS around 2250. Not a hardcore 3D guy, still learning stuff but getting proficient with some big air and sport flying.  The tail has always seemed to hold okay but I was still working on tuning it with my Ikon when it crashed so I cant say how good it was compared to how good it could be.  I feel like Im progressing quickly and starting to through it around a little harder. 

Set up as follows:
4025-1100 Scorpion
Rail 556 Mains
KDB 96 Tail blades
12t Pinion
Head speed governed at 2250

I'm leaning towards the ratio increase but I dont know if that's because it will get me in the air faster (dont have to deal with the return of the 54T) or if it is because it will benefit me. 

Thoughts?

[Chris Sexton]

2250x4:1 equals a tail rate of 9000. Matt recommends 9500-10000 on the tail. I would get the faster tail. Will help with tail authority.

Just my 2 cents.

[Mike Spano]

dang, now I am thinking I should count mine again.....lol....the E7 only uses the 54T though, so I should be ok.

I have had main shafts be labeled incorrectly before. package say E6/7, and it be an E7SE/E5 main shaft. but never a gear (that I have noticed).

my tail holds fine though, so maybe it is correct and mine was just tight...

[chad289]

Chris, I appreciate your 2 cents, and would gladly have paid more!  Im going to get the 12T ordered right now.  I had a hard time believing that as high of quality and as good of a fit everything has been that there wasn't some issue.  I just didnt think it would be the wrong part, lol. 

Thanks again for everyone's help.