IMG_04...
Carl
Andy Draper said the following in a letter he wrote me on 15th August.
" The Woodcomp scimitar blades are acceptable, however there is an issue
with the diameter. The maximum diameter propeller accepted on the Europa XS
monowheel is 64" (1625mm). If you wished to fit a larger diameter propeller,
you
will need to show compliance with CS-VLA925. Amongst other things to check,
the ground clearance from the propeller tip with the aircraft fully loaded, in
a level attitude and with a flat tyre must be at least 230mm."
Andy therefore seems to think you do have to have a minimum of 230mm
clearance with a deflated tyre. However, I agree with your interpretation of
the
rules, and I think he could be persuaded that with a deflated tyre the rules
only require "positive clearance".
Regards
John
In a message dated 28/09/2007 16:26:01 GMT Standard Time,
carl.pattinson@btinternet.com writes:
John,
Having tracked down the VLA specs I had a look at what it had to say about
prop clearances. Unless I am very much mistaken I dont beleive the tyre should
be deflated to achieve the 230mm clearance.
Here is the actual wording
"(a) Ground clearance. There must be a clearance of at least 180 mm (for
each aeroplane with nose wheel landing gear) or 230 mm (for each aeroplane with
tail wheel landing gear) between each propeller and the ground with the
landing gear statically deflected and in the level, normal take-off, or taxying
attitude, whichever is most critical. In addition, for each aeroplane with
conventional landing gear struts using fluid or mechanical means for absorbing
landing shocks, there must be positive clearance between the propeller and the
ground in the level take-off attitude with the critical tyre completely
deflated and the corresponding landing gear strut bottomed."
If my interpretation is right there have to be two checks made. You first
load the aircraft up to its maximum weight and the clearance has to be in
excess of 230mm, then you deflate the tyre and there should then be what they
describe as "positive clearance" .
Having said this my understanding is that most Classic Europas would fail
the VLA test even with the 1575 blade fitted (ie: the Warp Drive). However the
ruling is not retrospective so should not affect existing approved
installatons.
Apparently the XS monos are not similarly affected because the XS engine
mount raises the propeller by about 1.5" (compared to the mono. Consequently
the
1625mm prop can be approved.
None of which is any help to me - it seems the Woodcomp is a non starter.
|