[Al Posts: 1008 Status: Offline WWW]

Thanks John, I'll work through that list.


On the plans it said to have about 5lbs pressure at midpoint to deflect the belt about 1/2".  I used digital luggage scales when I fitted the belt to check belt tension.


Tomorrow in daylight, I'll measure distance between pulleys and check belt deflection and how many pounds it takes to pull the 1/2" deflection at the belt midpoint.


I'll check make of the belt tomorrow also.


The engine was a little over idle in the video, probably around 1200/1300 rpm


The last time out it flew perfectly, maybe the belt has stretched a little after the last trip.  I'll check the pulleys to make sure none are loose or have oil/grease etc in the groves.
 

[John Robertson Posts: 5272 Status: Offline WWW]

1. What is the belt tension (force/distance)?  Hard to tell which side is the driven one as it looks really slack!  Is engine at idle RPM?
2.  Driven and/or driver pulleys not fixed to shaft adequately.
3. Pulley grooves contaminated
4. Bad belt (what type/part#?).
Has to be one (0r more) of those.

 Trailer:

1. Push craft (on full hover) so the rear of the hull is 2ft behind the end of the ramp.
2. reduce power until craft rear settles on surface (front on full lift)
3. Drive trailer out fro under craft.

Absolutely no need to push the craft off the trailer!

[Al Posts: 1008 Status: Offline WWW]

https://youtube.com/shorts/mD1kcdG9kV0?

Difficult to see the belt vibration in the video  Can be seen on the short vertical section of the belt but difficult to make it out on the longer horizontal section

[Al Posts: 1008 Status: Offline WWW]

Went to take the Surveyor out again today and it was a pain getting it off the trailer to start with.  I'm thinking of building a new trailer, as this one is awkward.  Once off the trailer I flew it down to the beach and it started bottoming out like it did before     So I stopped the motor and checked the lift belt.  It looked OK but was quite warm.  The two prop belts were cold.  So I tightened the belt slightly and flew the Surveyor out on to the loch to see what lift was like.  It didn't seem too bad, so Becky stepped onboard and we set off reasonably close to shore and  headed towards the top of the loch.  I had planned on going to Plockton today, but wanted to check it was flying properly first.  Anyway travelling around 24mph at 2500rpm and the nose dropped again as before, so I turned around and went and parked it on the beach, then loaded it back on the trailer 


Today there was next to no wind, probably under 5mph.  XC weather said 2 to 3mph wind.


It was a new belt and probably has done less than 2 hours, three at most.


Something is causing the belt to slip, so will be removing the belt and checking all the bearings on the lift system to make sure none of them have a tight spot or feel rough.   I did notice that there is a lot of movement on the belt which' I'll try and upload a video to show.  I'm wondering if maybe the belt needs something like a guide block to stop it vibrating so much