[jhb] Re: Pireps
- From: "bones" <bones@xxxxxxx>
- To: <jhb@xxxxxxxxxxxxx>
- Date: Thu, 6 Sep 2007 15:47:19 +0100
Funny aircraft the Tommy..
Mostly benign to the point of being boring but this can trap the unwary.
Initial spin entry is almost textbook and is almost fun - but leave it in
for a few turns and it goes flat with the rotation rate almost doubling.
That's bad news because instead of looking at the ground going round you are
looking at the horizon - and that is very disconcerting. It was bordering on
disorientation for me and the pilot next to me was convinced the rotation
was in the opposite direction <g> but I shout louder..
Peter's right about the little twee flaps. They give sod all lift (which is
why the stall speed doesn't change significantly) so there isn't really a
short field approach speed.
It's a pity FS doesn't emulate drag for grass because it certainly takes
Density Altitude into account. Take off on a hot day and you'll use up a lot
more runway - which is why you may get into some of Gerry's strips on one
flight but won't have a hope in hell on another day (assuming you use real
weather) when it's hot.
If you think that temperature and weight don't make any significant
difference to take off and landing performance then watch this clip. It
ain't for the squeamish - but understand why a fully loaded Bonanza with an
OAT of +37 is a bad mixture.
http://video.fox40.com/Global/Video/...clipid=1712544
A friend of mine flew into Barton regularly - knew it like the back of his
hand. He'd been wary of going there at first because of the short runway but
he did his homework and calculations and it paid off. He was happy. Several
months later he'd become familiar with the airport and thought it was no
problem so, eventually, he took a friend along and then another until he was
regularly going there with a full load. Familiarity meant that he was happy
with the airfield and he stopped doing take off calculations.
As Spring lead into summer it got hotter. He arrived at Barton as usual one
July day, made the standard join, landed and failed to stop. He tried to go
around (worst thing you can do because if you are not going to stop in time
you certainly aren't going to get airborne again). As he went through the
boundary fence (accelerating) the posts took both wings off and he ended up
in the adjacent field in a relatively intact fuselage - and very lucky too
as the wings were some distance behind and burning merrily.
What went wrong? Loads of things in fact. He was over familiar with the
airfield so his landings weren't as crisp as they had been at first. Lack of
good speed control, a slight float and he was further down the runway than
he should have been. He was heavy - four people on board. It was hot too
which robs wings of precious lift. Finally it was a balmy summer's day with
a light and variable wind. Wind is your friend - with a 10kt headwind your
landing run is greatly reduced but pilots get used to this. Landing with no
wind eats up more runway but this is exceptional in the UK and so pilots
don't realise what the normal landing performance is - they become
accustomed to windy conditions and it affects their perception of landing
distances.
Any of the above factors individually would probably not have affected this
flight. Add them all together and it very nearly resulted in four people
writing themselves off.
When you are flying around Gerry's strips do you make a note of the
temperature? Of the wind strength? Of your weight? Understand how these work
against you and it will increase your chances of successful flights into
these strips. Accept that there are situations in which you simply won't be
able to land at some - but at least you won't die trying. There are far more
accidents these days at private strips than anywhere else - they've gone to
the top of the CAA table.
bones
-----Original Message-----
From: jhb-bounce@xxxxxxxxxxxxx [mailto:jhb-bounce@xxxxxxxxxxxxx] On Behalf
Of Peter Dodds
Sent: 06 September 2007 10:18
To: jhb@xxxxxxxxxxxxx
Cc: pdodds@xxxxxxxxxxxxx
Subject: [jhb] Re: Pireps
I've got a Tommy handling notes book somewhere...............
Surprisingly, it doesn't give short field techniques. the best i can give
you is for an aircraft at maximum allup weight (MAUW)
Stall speed clean 48 knots
Stall speed full flaps 47 knots
(The flaps do not add lift on the Tommy, only drag).
Landing distance ISA conditions and dry level tarmac 466 metres Add 20% for
grass = 560m T/O distance (dry level tarmac) ISA conditions nil wind 400m
Add 20% for grass = 480m
I don't thing FS can distinguish between long grass short grass, wet grass
or dry grass) but for for each factor you would multiply your ISA T/O 'T' by
20% So for long wet grass it would be T x 1.2 x 1.2 x 1.2 or almost 700m
T/O distance is the distance from standing to a height of 50 feet above the
runway. The landing distance is similarly from a height of 50 feet to a
standstill.
ISA conditions are Sea level and an atmospheric pressure of 1013mb and an
air temperature of 15oC.
The Tommy isn't a brilliant short field performer, but I'm one of a
relatively few number of pilots who actually like it when tame. When angry
it bites.
It could take you a bit of practice to get into places like Halwell. <g>
Peter
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