Grumman - Part 13
another month and more has flown by and it seems almost nothing
it is hard to keep the motivation up and running at a high
level - along with the 'one step forward and two steps back"
syndrome which of late has been common, there has been Easter
and sundry other public holidays getting in the way during
April. The result of that is that many firms and suppliers
close of course, and then one cannot get hold of stuff you
need, or get things done by said firms.
outlined in Part 13 to use mandrel bends, a longer and more
tortuous inlet tract (well, two tracts actually since there
are two carbs) and for this inlet manifold to be mounted to
the aluminium manifold is proceeding but slowly. What I found
is that the adaptor plate carrying the inlet pipes cannot
be bolted to the mounting surface of the manifold since the
aluminium is too thin to take a thread which would provide
strength. After tapping threads, I found that the bolts would
immediately strip the thread in the soft ally since that is
only about 5 mm in thickness - even tried helicoils
but they also would suffer the same lack of grip into the
to the drawing board yet again! I have made up a 10 mm thick
aluminium plate to be welded to the manifold and this plate
will give the necessary thickness so that threads can be tapped
which will actually have some strength and then the actual
manifold pipes, plus their adaptor plate of steel can be securely
bolted down with a gasket for sealing.
luck this can all be completed soon and then we can figure,
once the new inlets tracts are in place with the carbs mounted
and throttle linkage connected up, just how the cooling water
reticulation system of piping will have to be modified, since
this previously passed through the area at the rear of the
engine where the carbs will now repose!
visit two weeks ago from Andrew, who has a Grumman AA1B, the
only legally approved +6 - 3G AA1 in the world, and who is
a director of a company that builds big military vehicles
for a living - he pointed out that the problems of 'packaging'
everything is one common to his development work - and even
though his company has engineers, mechanics, welders etc etc
available in abundance, it still is a trying job sometimes.
life getting in the way, a move to a new hangar on the airfield
and many complications arising out of the decision to relocate
the carburettors, we have not been able to make much progress
on the job of finalising the manifold design and fully testing
few weeks ago however I did mount the new manifold and carbs
and cranked up the motor - it ran, after a fashion, but I
could not get it to run satisfactorily and the reason was
pretty clear - there was air being sucked in at the manifold,
either at a defective weld, and/or, as I later found, by the
fact that previous welding operations had caused the mounting
flanges to distort so that they are no longer flat!
it is time to file those down flat again and to check out
where the welds might have pinholes.
a lengthy lay-off over Christmas and into the new year, I
made the decision to move the aircraft from the airfield where
it costs money to rent a hangar and more money and time to
get to the airfield every time work has to be done - which
is every time! After a very poor final half of 2011 business-wise
some economies must be achieved whilst we hang on for better
times - whenever those may arrive!
malady set in! Oh dear me, the move appeared in my mind as
such a giant task, and in fact as an admission of failure
to be honest, that I actually harboured thoughts of selling
the project and getting the hell-out! Indeed I advertised
it at what I thought was a low price, feeling so frustrated
on many fronts as a result of the 'one-step-forward-two-steps-back'
bore you with the details but the appalling experience of
dealing with potential "buyers" who actually have
no money at all, or are deeply,deeply ignorant in the extreme
about aircraft, expecially experimental, or seem to think
that my aircraft has zero value so I must give it away, has
led to another but welcome state of mind - the bloody-minded
state that says "no way will you sell it - finish the
working on the aircraft to install some delicate interior
components rather than carry those loose and removing the
wings in preparation for the move has made me realise what
a fabulous airplane this littlest Grumman actually is - built
solid, built honest and a great flying machine, it cannot
be sold under these circumstance - end of story.
is coming home to my garage - saving me the ongoing expenditure
of the hangar and travel costs and I will be continuing to
'fettle' the motor - which is about all that needs sorting
out now and even that does not look like a massive job, consisting
mostly of getting my inlet system working well.
As a buddy
at the field said - "You have had time now to experiment
deeply over the past few years at the airfield with the auto-powered
concept - and you now know that it will work and what is needed
to make it fly"
know what? - he is right!