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Technical Chat Tips and Advice, including flying the Luscombe

Moderator: HTB

 #9024  by Jeff Smith
 Tue Oct 20, 2015 11:11 am

As commented on elsewhere on this forum, I recently crashed G-BVGW, my lovely 8A, and now own a Bolkow 208C Junior. It would be difficult to imagine two aircraft so different, One area that they are similar though, is the position of the fuel tank. In the Luscombe 8A the fuel tank is in the fuselage, behind the pilot, and above the luggage area. The Bolkow has its 22 gallon tank in exactly the same position, but in my opinion the tank probably sits even lower than the luscombe, as the fuselage is not as deep, being a shoulder wing design relying on a bubble canopy giving sufficient headroom for the occupants. This all got me thinking about the advice (still in circulation) about the Luscombe 8A needing wing tanks if a more powerful engine is installed, along with the dangerous practice of applying carb-heat for take off! The Bolkow has a 100hp 0200 and manages perfectly well without all this nonsense. Indeed, given that the Bolkow is an aerobatic design it is easy to imagine that it could be capable of manouveres that could lead to fuel starvation far more than the Luscombe could.

The Rolls Royce 0200 in the Bolkow has a mechanical fuel pump driven from the engine, and this seems to be well up the task of supplying the engine with fuel (at 4.5 gallons per hour, rather than the 3 GPH my 8A used to use). In addition it has an auxillary electric fuel pump that the POH recommends is turned on during take off, circuit work, and landings. To help keep an eye on all this, there is a fuel pressure gauge included on the instrument panel. This seems to m a far more elegant solution to possible Luscombe fuel starvation, than tearing apart perfectly good wings to install wing tanks. Of course, I realise it could only work if the new engine that was installled had the mechanical fuel pump, along with an electrical charging system to supply the electric fuel pump, but most people seem to go for 0200 installations anyway. The other big advantage is it allows the builder to retain the 'classic' lines of the 8A, without the additional windows, and parcel shelf where the tank used to be.
 #9025  by Phil Laycock
 Fri Oct 23, 2015 7:08 pm
Hi Jeff

Agree with your observations ref the original tank and mech and elec pumps. Biggest drawback would be the limited range ....IIRC its about 52 litres so with a O-200 burn of 22 litres per hour, it gives you just over 2 hours endurance.
 #9026  by Jeff Smith
 Sat Oct 24, 2015 9:21 am
Good point Phil.

But at least doing the conversion my way. An owner could have the aircraft up and running, and then look at the range required before looking at the options with additional, or larger fuel tanks. my bigger issue was with the requirement from the LAA to fit wing tanks if the engine was more powerful than the standard A65. Given the example I have described, I feel the LAA failed to look at the solutions and options available to reduce the risk of fuel starvation. Applying carb heat to reduce the engine power during the climb out, has to be an extract from the Monty Pythons book of flying! No doubt, we could achieve a similar result, by turning off one of the magnetos?