Interesting read. Recently I found a mechanical fuel pump was down on performance and another h36 the original fuel tap was not replaced. I initially had owner buy new Hardy fuel pump from Germany as fuel flow was well down on the 65lit per hour. It was that stupid Truma red diamond shaped fuel tap (original owner ignored the AD it seems) and was not rising enough and thus was restricting fuel flow to 25lit per hr. Again it was a rubber. With the ball valve from diamond fuel flow is up to 65 to 70 lit per hour.
So yes ALL rubbers need replacing everywhere they may be. Also in fuel line replacement that stupid copper line connector behind Muffler can weap. A the later h36 have the fuel line comes from tap to above the rhs pilots peddles and goes through fire wall in an AN bulk head fitting. Then there is a short run to fuel pump or use Teflon braided fuel lines. Ian McPhee 0428847642 Box 657 Byron Bay NSW 2481 On Sat, 23 Jun 2018 8:19 pm Martyn Cook <[email protected]> wrote: > Hello fellow Dimona operators > > Allow me to introduce myself to this group: I operate an H36 Dimona > built in 1983, serial number 3667, registration ZK-GPH, with about 1300 > hours on it. I fly from Papawai which is a gliding club near > Wellington, New Zealand, and the aim is to use the motor glider to > accelerate aspects of glider flight training. I always enjoy the DOG > posts I read, especially the hints about what to look out look for . . . > and I sense it's now time for me to contribute. > > I purchased this aircraft with a fresh annual, so all the fuel hoses had > been replaced. But when I had an empty fuel tank one day I thought I'd > dismantle the fuel drain tap, and the O'ring lurking inside crumbled as > I tried to flick it off the shaft. So the rubber hoses had been > replaced, but not ALL the rubber bits. For all I know the O'ring might > have dated back to 1983. I spent a few hours that night googling how > many general aviation flights had ended badly because the fuel had > drained from a leaking fuel drain during flight. Sigh. Actually, I > also had to replace the electric fuel pump because although it clacked > away it was unable to lift fuel into the carburettors. And the intake > filter at the electric pump had some white, fibrous stuff in it, > possibly from the previous GRP tank (it's now a metal tank). You might > judge that I'm paranoid about fuel (I am) and I like to check the > c=system fully from one end to the other. > > But wait, there's more! Landing on a short runway means I depend on my > wheel brake occasionally, especially in calm conditions. Again, the > brake hydraulic hoses had all been replaced on schedule, but I became > curious about the other rubber bits in the brake system? First clue was > a binding park brake. Second clue was very dirty brake fluid when I > drained the left wheel calliper. The brake master cylinder was rather > difficult to access for removal, but inside it I found 6 O'ring seals, > plus a lot of gunk and corrosion product. Two of the seals were in very > poor condition, and 2 more were well worn. Fortunately I could figure > out the replacement O'ring types from the Parker-Cleveland catalogue > ("master cylinder - push type with parking brake") because measuring > distorted O'rings is a tricky business. My next job is to pull the > slave cylinders apart and clean these thoroughly before reassembling > everything. And new O'ring seals. And use automotive brake fluid. > > Lesson for me is to attend to entire systems, not just the big bits or > the bits that are easy to get at. > > With kind regards > > Martyn Cook > Pukerua Bay, New Zealand > > > --------------------------------------------------------------------- > You are subscribed to the Dimona Owners Group mailing list. > To unsubscribe, send email to: [email protected] > >
