Control input during loop

In article , Big John
wrote:

For example in the P-51. You are trimmed up for cruise and decide to
do a loop. You drop the nose and pick up air speed.

John, are you saying a stripped down civilian P-51 cannot pull up from
level flight into a vertical loop without first diving for additional
airspeed?

John, are you saying a stripped down civilian P-51 cannot pull up from
level flight into a vertical loop without first diving for additional
airspeed?



Yes........cruise speed in a Mustang is 240 mph and a loop is flown at 300 mph.
You can try it, but you'll be very ragged at the top. You might even fall
out!!
VL

In article , MLenoch
wrote:

John, are you saying a stripped down civilian P-51 cannot pull up from
level flight into a vertical loop without first diving for additional
airspeed?

Yes........cruise speed in a Mustang is 240 mph and a loop is flown at 300
mph.
You can try it, but you'll be very ragged at the top. You might even fall
out!!

How many G pull is that?
Do you maintain a steady g throughout the pull?

It flies best with an initial pull of 4 G. G is not constant during the loop.
It may be half a G at the top. On cooler days, I can fly the loop at 3 Gs for
the initial pull; it is easier on the 50+ year old wing. But, when not doing
low level airshow loops, 3 G loops are always OK at higher altitudes. The
problem is getting too slow at the top, which is uncomfortable during an
airshow display.
VL

mlenoch

Sounds like you are current in bird. Just took my shoes off to count
and last flew the bird 54 years ago at Miho Japan (35 Ftr Sq, 8th Ftr
Gp) )

Flew D10 to D30's and K's. Had guns and full load of ammo and armor
plate behind pilot. This additonal weight required a little more speed
as I remember (maybe 325-350???)

Slow on top and G's causes the laminer flow wing to stall (and bird
snap) as sounds like you have found out ) Inverted spins took some
altitude to recover.

During WWII birds were red lined at 505 mph. We got a directive about
1947 that reduced the red line to 450 mph to put less wear and tear on
the birds. Are you still using the 450?

We used 61-3000 and 145 octane fuel for take off and were told that
that power was needed to keep the engine clean?

Talking to a jock at Ellington some years ago, he said the 51's now
were using 45-50 inches for T/O (easier on engines)? Or may be the
lower octane fuel available now???

I enjoyed my 650 hours in the bird.

Big John

On 27 Oct 2003 02:53:33 GMT, (MLenoch) wrote:

It flies best with an initial pull of 4 G. G is not constant during the loop.
It may be half a G at the top. On cooler days, I can fly the loop at 3 Gs for
the initial pull; it is easier on the 50+ year old wing. But, when not doing
low level airshow loops, 3 G loops are always OK at higher altitudes. The
problem is getting too slow at the top, which is uncomfortable during an
airshow display.
VL

100LL fuel limits the engine to 55" on takeoff to prevent detonation. The
current owners today (non-racers) seldom get above 400 mph. Most of them seldom
do aerobatics and thus likely never get above 350 mph. The commonly know speed
limit is still at 500mph. There are about 120 airframes flying in the US, with
about 300+ still in existance worldwide. Cruise is flown at 35" which produces
220kts/240mph approximately......depending on ambient, bomb rack installed,
antennas, etc. That's about 55% power. Like John said, it needs speed to get
over the top of a loop, otherwise it can stall and depart.
VL

In article , MLenoch
wrote:

It flies best with an initial pull of 4 G. G is not constant during the
loop.
It may be half a G at the top. On cooler days, I can fly the loop at 3 Gs for
the initial pull; it is easier on the 50+ year old wing. But, when not doing
low level airshow loops, 3 G loops are always OK at higher altitudes. The
problem is getting too slow at the top, which is uncomfortable during an
airshow display.

Two more question, if I may...
What has the airspeed at the top of the loop decayed to with 4G pull?
With 3 G?

Two more question, if I may...
What has the airspeed at the top of the loop decayed to with 4G pull?
With 3 G?

At 4G......110 kts is OK and preferrable. At 3G, you can get it to float over
at 80 to 90 kts. Also, just depends on how long the G pull is sustained during
the ride up, as well.
VL

At 4G......110 kts is OK and preferrable. At 3G, you can get it to float
over
at 80 to 90 kts. Also, just depends on how long the G pull is sustained
during
the ride up, as well.

At OSH each year, where you get to see a variety of WWII fighters doing
fly-bys during the Warbird show, I've noticed that some Mustang pilots are
considerably less aggressive on the pull-up and wing-over than others. I've
often wondered if this is a limitation of that particular aircraft, or if
that particular pilot is simply taking it a bit easier on himself and the
bird.

The most aggressive pull-ups I've seen are with that red Corsair racer and
the Bearcats. Their vertical penetration (and ability to sustain the climb
through the top of the half-loop) is most impressive.

I always kinda feel sorry for the occasional P-40 and early naval fighters
that participate, since they obviously can't keep up with you guys... :-)

As always, I (for one) appreciate you discussing this on-line with us Spam
canners...
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"