>
> 1). What do you think of dry vs wet oil sump? All comments and
> suggestions
> welcome
>
> 2). As it is impractical, if not impossible, to make a fully
> aerobatic
> rotary engine on the basis of a Mazda block, what level of
> "limited"
> aerobatics capabilities is acceptable/wished for? I am >especially
> concerned
> with vertical or near vertical manoeuvres... tricky situations >for
> rotaries...
>
> Thanks in advance for the feedback.
>
> Francois Badoux
>
>Francois,
>1) Dry sump gives you much greater flexibility. I plan to use dry sump
>on my 20B from the start. With respect to inverted operation, a
>pickup with a dedicated scavenge segment can be placed at the top of the
>engine to scavenge inverted. You have probably thought of this but I
>must offer the thought.
>
>2) Your concern with vertical maneuvers is drain back problems? This
>could be the tougher of the problems to surmount. But since so few of us
>are Sean Tucker it is probably the least often used acrobatic mode for
>most of us. (straight and level is fine with me for the most part)
>For crankcase pickup most of the auto applications use pickups at the
>front and rear of the pan anyway. (for acceleration and braking) Your
>concerns about filling the rotors is a much more serious item. With dry
>sump you do have the option of placing more scavenge pickups in critical
>areas. I have seen V8 engines with 6 or 7 scavenge segments; in addition
>to the oil pan they have pickups at the back of the valve covers and the
>back of the intake valley. Tests in the past by Chevrolet showed the
>more oil you could remove that wasn't in the bearings (drain back oil)
>the more HP you could generate. There is a point of diminishing returns
>on this of course. We need to concern ourselves with weight of the added
>plumbing too. Dry sump does give you these options though, wet sump
>doesn't.
>Bill Jepson

Francois, my automotive experience which is a drag racing back ground,
proved the wet vs dry sump showed no hp difference if designed for the
application ie 1 G gravity and 1 or 2 G's lateral acceleration. The wet
sump
can be designed for this! All you want to do is get the oil away from the
rotating assembly and then both systems are equal.

The big advantage, was the engine with the dry sump could be lowered in the
chassis for better aerodynamics and reduced weight transfer!This may be a
big factor in a high speed aircraft too!

Not being totally familiar with the rotary I would think a sump or pick up
point could be located on the engine so as to scavenge oil from the
rotating
assembly in a 1 or more G negative system. In the piston engines most
people
use an accumulator to provide pressure when oil is not available from the
sumps via the inverted systems ie in vertical maneuvers or in slow inverted
maneuvers where the inverted system has not made the switch over!

Just a few thoughts on your subject!

Regards
Ron

I just got this weigh scale from Robin for a Christmas present. I have been
looking for a scale like this for years. Robin found it in a farm
supply super market here in SZP. Thanks again Robin.

Getting to the point this rear main bearing holder weighs
a bunch and only has one oil drain back hole. It is conceivable that a
bunch
more drain back holes could be drilled reducing the weight of this heavy
part and enhancing the drain back at the same time.

Paul Lamar ...No rotor no motor.

Good point Paul,
A point for Ron to consider, you may be able to get your drag race
engine to endure 2G acceleration with a wet sump, but when was the last
time you made a pass inverted?
Bill Jepson


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