Hi Ian, Thanks for that … I have taken the spinner off this morning and had a good look at the latch. I think the problem is that I maybe overdid the lubrication of the centre shaft as the latching system has a lot of oil on it … just around the latch plate. So I think the best option is to give the latch a good clean off and try to keep any grease off it. It would figure because the engine has around 50 hrs and this problem has just happened. It seems to be ok when the airspeed is higher though. I guess the counterweights put more load on the latch keeping it in. There is no evidence of any damage to the latch plate or the ring it latches on so I will try getting rid of the oil / grease around it. The blade rotation “play” is the same for each blade … can’t tell you the exact amount but seems quite OK.
A week or so ago I flew it direct from Drury (in Auckland) to Ashburton (about ½ way down the South Island. Took 5 hrs and around 70L fuel) It went really well I have installed one of those MGL fuel computers which is just fantastic … able to calibrate the existing VDO fuel sender and also has a fuel flow sensor. It is real nice to know EXACTLY how much fuel is available. That trip also included Pat and I going from Rangiora to Greymouth … Rangiora on the east and Greymouth in the West…. Over the main divide mountains …. I was really surprised as the little rocket climbed to 9000 feet both ways. In fact the engine seems to run really well above 7000 feet. I have a couple of things I need to address … It tends to roll to the left above 90 Kts … not too bad but enough to be annoying .. I have been putting tabs on the wings to improve that and secondly, one side cylinder head (the LH side looking forward) runs significantly hotter than the other (except above 7000’) I think it is a mixture problem. Re Grant … I have known him for a long time. He is probably one of the most competent glider repair engineers I have known. His background is as a fitter and turner but has been working on gliders now for more than 10 years or so. He has replaced numerous canopys and has rebuilt a duo discus from the rear cockpit forward … to name just a few. He also replaced all the aileron bearings in our Dimona … I made the holes but he did the rest. He is a loss to his previous employers I think. However I believe he would need some support in the administration area. Hope that helps Best regards Ian Williams From: [email protected] [mailto:[email protected]] On Behalf Of Ian Mc Phee Sent: Wednesday, 18 February 2015 12:14 a.m. To: DOG LIST Subject: Re: [DOG mailing list] Dimona prop issue Yep been there done that. Where will I start? Our prop went to Eric in August and back mid September for the 6yr 11month service. It came back and would change to coarse and stay there half the time. It then went to gulf late September and slowly got worse. After a week at gulf reached stage it would almost continually return to climb. It got so bad I changed pitch to mid position so the pilots could get home. We have S2500 engine so no issues. Complained to Eric sent it down on Oct 9 and there it was for 15 weeks as Eric did not know what was wrong. I say again 15weeks. Dennis Stacey visited him as he took the prop out of the box. Others visited on my behalf. No joy. Conclusion was from Germany to fit an exchange boss at $250 total was $480 on top of $4800 to "service the prop". Why that was not done in first place I will never know. When at burketown there were 4 motorgliders there and ours was just out of service & had more blade rotation play than all the rest. It is back now and zero play infact prop has never been better. First time every time. How much blade rotation play do you have. Now a LAME friend advised me with engines and props UNLESS you are doing charter there is no calendar service ONLY hours service. Thus I asked our GFA Dennis Stacey and he sent me a heap of notes and links confirming this. So from what Dennis tells me we can ignore the 6 yrs 11month service & revert to makers hours requirements if not in charter. I go along with if it ain't broke why fix it. I will never ever go back to Eric for service. I would rather send it to USA or Germany but not AUSTRALIA AIR PROP. Eric is a nice bloke BUT. What a saga. That is why I have a falke with FIXED PITCH & no way would I consider a 2 position prop. So as you see I am not happy. GRRRRRRRR Ian Mc Phee 0428847642 (Ian what do you know of grant nelson from your area in NZ. Keepit club have set him up a workshop at keepit to do repairs) On 17/02/2015 8:04 PM, "Ian Williams" <[email protected]> wrote: Hi all, The little Dimona here in New Zealand has now just passed 50 hrs and going real well. However we have started having a problem with the prop which the considerable collective experience of this forum may have had the same issue Which is …. Changing from fine to coarse pitch is OK (though does need a significant pull) however if the airspeed is low(ish) it will drop back into fine pitch. It is a bit random … I have just been to the South Island in it (about 12 hrs flying time) at higher airspeeds it did seem to stay in coarse pitch. Any ideas??? I will take a look tomorrow… maybe a good clean of the latch with WD40 then some oil may work. But I would be really interested in any comments. It is a standard Hoffman BT prop and has had the AD embodied …. 50 hrs since overhaul by Eric. I have checked all the things obvious like thrust plate run out, the thrust plate bearings etc all look as supposed to. Best regards Ian Williams Dimona ZK-GCB
