I bit of more information on steves bearing failure. It appears that the thrust shims that are installed on the pinion shaft may have contributed to the bearing failure. Rotax claims that if the shims are not set correctly then premature bearing failure will occur. I have in my instructions to install the shims but some gearboxes dont have the shims just depending on the clearances. I should enphasize to everyone that it is a good idea to check this clearance if you get a used gearbox and everytime the gearbox is assembled. The shims are basically just a thin washer and are available from rotax. Now that steves bearing is bad we cant take that measurement to conclude that this was the cause but its pointing in that direction. On a side note while going through rotax service bullitins i found a that the c gearbox load rating is the same as the 912 gearbox.
Steve henry made it back f to idaho from the copperstate flyin. He noticed his clutch drum was rubbing on the gearbox housing so investigated more and noticed one of the rotax ball bearings had failed. The cage was missing and the balls were free to float. It is the lower shaft bearing. We are just hypothesizing right now that maybe the clutch drum causes heavier loads on the in put shaft bearings. He is going to go back together with the stock rubber dampener and no clutch drum. Put hours on it on and inspect the bearing around the 50 hour mark and repeat.
When you say the springs were loose, did they loose some of their elasticity or did the face plate bolting come loose? I heard that the main killer to these clutches is running them up and down at around engagement rpm so they are slipping a light perhaps in a amphip application. I heard if you go past the engage point and don't hangout there a lot heat wont build up and ultimately causing the spring to weaken. I know for a fact Steve started having that noise almost right away after installing the clutch and he called the designer of the clutch noises and he assured Steve that it was nothing to worry about. He questioned Steve on the application and the HP and he said it would be fine at the higher HP because of the high RPM since it will push the weights out even hard into the drum and that the drum is robust enough to handle the extra centrifugal force. But knowledge and experience being king here I am really interested in your specific failure parts and what exactly came loose. At what hour interval did you experience a failure. At what rpm did you run the engine at primarily. Sorry for all the questions I just want to gather as much data as possible a compare to the RX operating conditions and to possibly save Steve Henry from a failure. Thanks
yes, I did but soon after a purchased the kitfox a Avid came up for sale that needed an engine. So I decided to do the engine install in the Avid. The kitfox does prrtty good with 80hp 912 thats in it so im considering selling the kitfox now and focusing my efforts on the avid
I would aim for level on the float bowl mounting surface but if you wanted to lean it either way within 15 degrees to optain a particular engine position or thrust line you wouldnt affect anything. I have ran the engine on the run stand in all kinds of positions to see if it affected fuel flow or overflowage and it didnt miss a lick or drain fuel. On the snow machines I would imagine they are put in more extreme positions than most of us would.
Greg, thanks for posting im sure everyone loves the pics and the info. I cant wait to see steve's apex engine adapter he gets from you. Heck i might buy one from you if steves works out. i dont currently have plans to build one for the apex engine if your works good.
Greg mills, some of your information here is not true. I do appreciate you sharing some personal experience with the engine as it may be helpful to others. You kind of make me out like a copy cat and i dont appreciate it. Early on when i first started hearing about the yamaha snowmobile engine i did in fact inquire to you about your adapter kit and after i found out you were using the stock cover with a chain drive bolted on top of it I wasnt interested and came up with my own that completely replaces the stock cover and bolts a gearbox directly to the engine and my intentions were not to mass produce these or even make another but my friends wanted some so i got the cnc program and now i can make them as needed but i in no way have a business doing this as you. After i came up with a good adapter with some reputation you in fact inquired to me about buying my adapters if i would modify them to accept your chain drives and i told you i wouldnt do that. Over last couple years i have been watching to see if you have completed kit ready to sell and not just acepting deposits. Are you now actually shiping out kits? Because some people on here might be interested in the chain since it brings the prop closer to the top of the engine where it could be easier cowled. I know I sold a adapter kit to Steve Henry of wild west aircraft and he told me he gave you deposit of $1500 for one and that you were still in development but that was about a year ago. Did you get steve out one yet? It would be interesting to see how it works in the highlander. He is currently flying with Skytrax adapter.
Angle the engine to the left 3 degrees. For pitch angle make the prop. Flange paralel with the firewall that is if your firewall is set up to be perpindicular with flight angle. If you font know for sure the set the prop flange perpindicular to what ever is on the fuselage that is level during flight. If you make shim changes later to the engine mount you may have to modify your cowl
This is Steve Henrys engine install. He has a littlw over 60 hours on it. He reports it has as much power as a big bore 912 with a turbo. He recently installed the rk400 clutch and seems to be working good for him.
dholly, I don't understand your question. This is a dyno run of the engine for any application. It is raw torque and RPM numbers with the engine bolted to a dynometer. what is a "Aircraft application dyno chart" could you possibly be asking for real world numbers as far as airspeeds and rpms for a given airframe with this engine? If so what numbers would you like to see? I have a little bit of data of this engine flying in Steve Henrys Highlander and a number of different trikes and gyocopters. Just in general Steve is able to climb at a steady 1900 fpm from 1000msl. his WOT level flight is 124 MPH with the 3:1 ratio gearbox and slightly faster with the 3.47 ratio. He takes off in less than 100ft. In comparison to the his past big bore 912s with nitrous the stock RX1 pulls harder on a pull scale and pulls harder on takeoff. Static thrust pulls were 580-600 lbs depending on the day. Those pulls were with a 80" X 46" Prince p-tip prop. Both highlanders weighed right at 700 lbs. I hope this info helps but If there are any other aircraft data points that you are looking at, let me know and I may have them.
As a update to Steve Henry's highlander RX1. He is replacing the header for one that has longer primary pipes so he has better low end power and better throttle response. He is having trouble making spot landings for competition purposes. I have been using a different header here lately and it really changes the low end torque. Wide open power is stiil about the same.