![]() |
Quote:
The pilot of this aircraft is lead to believe that the aircraft will function normally using a both position on a fuel valve. This is not normal. The pilot of any aircraft is lead to believe that the aircraft will function normally if the ignition switches are left "on". This is normal! If you bring an aircraft with a modified fuel system to me for inspection, you must prove to my satisfaction that your modifications are feasible. If you think that a "both" position on an otherwise standard RV fuel system is feasible, then you shouldn't bring your aircraft to me for inspection. |
Quote:
This airplane was certified by someone who pulls their pants on just like everyone else here. I simply vote to give them a break. |
And to add, I'm convinced that adding a "both" position to an RV is going to increase pilot workload rather than reduce it - but properly managed (i.e., don't use the "Both" position), it is not "unsafe".
There are plenty of single engine certified aircraft with far more complex and difficult to manage fuel systems than an RV with a "Both" position. Some older Beech products and even the PA-22 with an aux tank comes to mind. Just about every Rocket has you pass through "OFF" every time you switch tanks - a very specific "Fail" in todays aircraft design philosophy. Best to add the proper valve, but going so far as to ground an aircraft owned and flown by an aware pilot until that happens... a bit much. |
Quote:
Bevan |
Quote:
Some variation on that theme likely applies to most selector valves. If the label says 'both', it *implies* it's ok to operate there, but if it just says 'left-right-off', the pilot should pick one. :-) A friend sold an -8 with the current 'stock' valve; 45 degrees L & R for tanks. Buyer had fuel starvation in flight with fuel in the tanks; later said that he thinks he might have aligned the handle either fore/aft or in line with the spar because he'd previously owned an RV with one of the old style valves. Nothing wrong with the valve or the label; he just didn't select a labeled position. To the OP: If you don't find a blocked vent, is it possible that you finally found the right conditions for the plane to draw from only one side with the selector in 'both'? Even a high wing Cessna will feed unevenly when running on 'both', though it's difficult for it to suck air (unlike low wing planes). As a FWIW, on my -4, with less than ~1/2 tanks I can disconnect the line from the tanks to the (stock) Van's selector valve without fuel flowing. You can check for actual flow by selecting 'off', and disconnecting the fuel line at the engine or gascolator, as others have recommended. If you use a tank leak test setup (balloon on one leg of at T fitting, or a manometer tube on the T), you can select a tank and pressurize the tank through the vent. If there are no blockages, you can easily move fuel through the valve and out the line in the engine compartment. Then select the other tank, & repeat. The balloon or manometer tube will protect the tank from over-pressure, & still allow enough pressure to move the fuel through the open valve & line to the firewall area. Charlie edit: You won't get 'bubbles' in the fuel by blowing in the vent, unless you have the tank completely full & that wing is 'low'. The vent is (or should be) at the highest point inside the tank. |
I'm with Mel here. As an A&P his finances are at risk here.
(Can you see the widow's lawyer in court? He'll hold up THIS thread, and say that if ordinary people thought this was bad, then an A&P should surely have known...) |
Are we still talking about the OP and this one specific instance of troubleshooting, or are we off in the twilight zone again?
|
You are correct. It is experimental and you can do what you wish. But when an airplane goes down because the pilot was flying "on both" and one tank became too low, it goes against all of us flying these homemade airplanes."
You may have the last word. Please don't call me for an inspection. |
Quote:
Bottom line here is the RV's are a LEFT-RIGHT fuel system. |
| All times are GMT -6. The time now is 02:17 AM. |