I am in a small group flying a Luscombe 8E. I’ve flown it for 15 hours or so and quite enjoying it. Whilst it was rebuilt 10 years ago when they installed a venturi fed AH, the AH does not work. I hasten to add that as it is a VFR only aircraft, I don’t strictly need it for fair weather local flights, and basically ignore it, focussing on flying by attitude/visual cues “out the window” until now.
Having said that, in part due to comments made by a number of you about fixing things whilst they are small to save money/bigger problems later and also my outlook that:
There is good knowledge in the group of 6 other owners, but they fly short locals now (they had their adventurers over the years in the aircraft) so it is not a priority for them.
In the cruise last week, I suddenly noticed that it was working, later, it was not. Suction was about 4.5 / 5 in mg at 2200 rpm so am wondering if it has something to do with the inlet filters (?). FWIW, the DI is also not working (great fun navigating with a whiskey compass, although I had SD as back-up).
Any thoughts on what the issue may be? My thinking is to take this to the syndicate with some ideas on what might be the problem, and then enlist some of the more technically minded ones or our inspector – I don’t want to just have an amateur fix, I would like to trust that it is fixed and working – which may involve eventually taking it to the shop, but I always like to have an idea of a problem before asking the experts/engineers to trouble shoot it at cost. Thanks in advance!
I just had exactly the same situation where vacuum was fine but AH only worked intermittently – it was first slow to erect, and then it became unpredictable, sometimes showing a correct attitude and sometimes giving a 20° error in roll – all within mere minutes. I called Česká Letecká Servisní here in Prague and described them the symptoms, and they said right away it would most likely need a cleaning only. I brought it down to them the same day, and one week and 125 euros later I had a working AH. As to the inlet filter, it is typically an external device that you change every once in a while, and if AH turns out to be dirty indeed, I’d certainly change it. The filters I’ve seen are extremely unlikely (if at all possible) to get clogged to the degree of not letting any air through.
Thanks very much @ultranomad, we may start by replacing the hoses outright. I also have a doubt on how effective the venturi is at “powering” the AH as well.
