Marty_d

I fully agree with that and wish I had!! I drilled out the rivets holding the L/H seat pan the other day in order to mount the battery isolator under the seat. I've left it loose now until I get everything else done.

I'd also be interested in that, at roughly the same point. (Although mine's a 701, the main gear and rudder pedals inc. cylinders are off a Sav, so the system should be the same.)

The answer to this may be completely obvious, but why isn't trim automatic - ie mechanically linked so that when the control surface goes one way, the trim goes the other?

If they do Savannah legs then Zenith CH701 is a straight swap too... good place to put a lighter component too because it's not far away from CG.

Could I please get some more info from you JG? Any recommended brand / type, mixing ratio etc. I want to paint the plane hopefully this summer. Probably white with blue trim. Thanks, Marty

Maybe "motorvated"?

They'd want to be bloody good for $3,000 (Aus)

Even worse - every decision he made had to be approved by his personal astrologer. Literally. He consulted Joan Quigley before doing anything.

The plans for my 701 are American. All length measurements are in millimetres, but thicknesses are in 1000ths of an inch and rivet/bolt sizes are in fractions of an inch.

It's horses for courses, isn't it. If you've lost your engine but have control and there are places to land, then you wouldn't pull it. If on the other hand you had a control problem, or more likely medical problem (heart attack/stroke etc) then there's a case for pulling it.

No offence taken! As for removable - it would be a reasonably big job to take the wings on and off, but it's doable. There's only 2 bolts at the wing root, but another 6 to get the struts off on each side. Plus of course an inspection panel to access the fuel connectors.

Well, I still don't have a home airfield for this plane. I may have to end up trailering it, and if that happens, I need some way to take the wings off - hence I think having the ability to disconnect the wing tanks would be a good idea. While I do support the metric system, I don't mind referring to 3/8" hose when that's what's written on it.

I've been flipping through ads on the internet until my eyes bleed. I actually have 4x 1/4" quick disconnect fuel fittings, with integral shut-off when disconnected (from Aircraft Spruce) but following the "fuel flow" discussion I think I'm going to stick with 3/8" from tanks to engine. From everything I've seen there are a lot of 3/8" quick disconnect fittings but none of them have integral shut-off. This is probably fine in a car where the fuel tank is lower than the engine but doesn't work very well with wing tanks. Aircraft Spruce only stock the 1/4" ones. Does anyone know of a supplier who has the 3/8" ones with shut off? Preferably panel mount but at this stage I'll take what I can get. Thanks!

When I was looking into one for the 701, the connections are on the main undercarriage (which is a solid spring of aluminium) and the welded cabin frame assembly at the front. If your aircraft has lost either of those two bits following structural failure or a mid-air, you're already dead.

That's true, but I don't think it's a big issue. I can't think of a reason that I'd want to shut off a full tank individually - and if I need to shut off both tanks there's the master valve. Fire in the rear fuselage is the only reason I can think of, and with 7 litres of fuel sitting in the header, I'm pretty well screwed anyway if that happens.

A mirror? (Just trying to think laterally here!)

I was discussing a cross-porting system with Bob, but the trouble is, I don't have a barb high on the L/H tank and there's no easy way to get to it. The other thing is the wing roots on the 701 come downward which means any cross port could not be straight across, it would dip to a low point in the middle. Thanks Nev - I hope I enjoy it too!

That looks like a massively broad wooden 2 blade prop. Constant speed?

Try about 12 years to get where I am now... mind you I did have to fabricate everything myself. I was hoping to finish by the time I hit 50 which leaves me about 7 months - don't think I'm going to make it!

New diagram:

Sorry, should have mentioned - tank vents are in the fuel caps, furthest point outboard on the top of the tanks.

Hi Nev, As Bob says the T would be on the fuel return line. Theoretically if the fuel return line were full of fuel (not sure how likely that is with 1/4" line) then it could spill down the T'd line into the header tank - so that doesn't matter either. I guess the main thing is that if any air does get into the header tank, it finds the highest point and goes back into the top of the tank. This is just to keep the low fuel sensor off so I don't have unnecessary involuntary clenching. A diagram of what I'm thinking is:

I haven't quite got there yet, but I look forward to the responses! Have you checked out Mark Kyle's thread about his Sav rebuild - not too long ago he was describing the painting process. He got a load of white from one of the airlines I think.

So it seems like I should stick with 3/8" from the tanks onward. On the R/H tank I have a 1/4" fitting at the top for fuel return. According to the Rotax Heavy Maintenance manual, this comes from a 5-way fitting bolted to the compensation tube running between the carbs. 1) Fuel in from the mechanical fuel pump 2) and 3) Fuel out to the carbs 4) smaller fuel out to the fuel pressure gauge 5) smaller fuel out (return) to the R/H tank. That's fine. But the other thing I have on the Savannah header tank is a breather tube that's meant to go to the top of a tank (usually the L/H one I believe). My tanks are hard to get to - unlike the Savannah, the 701 doesn't have an access panel below the tanks. So if I want to get a tank out to modify it, I either have to drill out a fairly large area of wing skin rivets or cut the aluminium away under the tank and replace with a panel (either riveted or screwed) like the Savannah. So I'm trying hard NOT to modify my tanks in any way! Question 1: Could I put a T fitting on the 1/4" hose that comes from the TOP of the R/H tank (this is the fuel return) and run the header tank breather to that? If the T was very close to the tank would that work? Question 2: What diameter hose/pipe do people use for the line to the fuel pressure gauge, and also the fuel return? I'm thinking 1/4" for the return because that's what I have at the tank end - is that standard? Below is a photo of the R/H wing root with top root skin removed, showing the return line at the top left side and the fuel main line at the bottom right side. So question 1 refers to plumbing a T into that top left return line, right before that rib beside the tank, then running that down to the header tank as a breather line. Thanks! Cheers, Marty

Hi all, Trying to work out whether I can get away with 1/4" ID aluminium tube from the wing tanks down to a Y or T junction before the Savannah header tank. From there the single hose can be 3/8" which I think is the barb size at the top of the header. (I can also use 3/8" from the header to the engine). Reason being, I have 4 panel-mount quick release fittings from Aircraft Spruce which I want to use in the wing roots, in case this becomes a trailerable aircraft. These are 1/4". Back of the envelope tells me the area of a 1/4" cross section would be 31.66 sq.mm, so 2 tanks = 63.33 sq.mm. Compared to this a single 3/8" area would be 71.2 sq.mm However I have had advice that it's all about ensuring sufficient fuel flow, based on a maximum of 27LPH for the 912ULS. How do you calculate this? There are online flow calculators but one of the variables is pressure (bar). Is there a set variable for this based on the mechanical fuel pump at the front of the engine? Thanks, Marty