Stab. I'll have to take a closer look next time I'm at the airport
The camber is not much, compared to the fat stabilizer on the 701, but
from what I remember it is opposite in format from the 701
Many planes have pretty well symetrical stabilizers.
I guess "lifting tail" isn't totally accurate - but a lot less of a
downforce tail. Different hacks for different tracks - a faster plane
gets more downwash from the wings thet forces the tail down much more
at speed. A slow-flying plane like the 701 and Pegazair depends more
on the reversed airfoil for the downforce.
On a very fast plane like the p51 the stabilizer is almost like a
knife blade or a plank - not much camber either way.
Sept 20, 2011.
At 6:30 the lake was so smooth it was glassy.
At 7:00 things changed!
The cold front moved through and the wind picked up from zero.zero
to over 20 gusting 36(!).
I had met Jim and his family earlier, circling each other to speak.
They bought Stephen's Catalina 27 and were hoping the front would bring
It did. Ob boy did it did!
Wind went from nothing to half a gale in nothing flat.
Good Times crew hadn't been out in this much wind in this boat before.
They had a bit of trouble getting the main down downwind.
But it finally did come down ok.
I was just trying to keep from running over them!
At least it wasn't a totally boring afternoon!
Some spray in the face, a couple of cold shots of adrenalin,
and all was right with the world again.
Not a lot of video here, my phone kept dropping clips.
(I learned that it does that if I don't close them properly)
But sometimes I'm just too busy to worry with buttons!
This was definitely one of those occasions.
I'm impressed that I got what I got.
From a telephone?
Yeah... do you? Although I have lots of hour PIC, I've never flown a
full-scale pylon racer. But (just like the guy in a Holiday Inn Express
commercial) I've flown model pylon racers. Real (not scale) speeds of
200+ mph. They are not "toy" airplanes, they're real airplanes made
smaller. They behave to aerodynamics just like big ones (although they
tend to leave less wake turbulence<G>).
We trim 'em out for max speed. Then we honk on the stick pretty hard at
low speeds, just to keep the nose up. So what?
The ONLY reason these full-scale racing guys want to land for, at all, is
so they can gas up and do it again! So long as the aircraft handling is
survivably safe at landing and takeoff speeds, all they're concerned with
is how clean they can make it at full speed.
Since one _can_ adjust one's approach speed, there need not be any
You are wrong Sir. The P-51 was designed to meet the specifications
set out by the British Purchasing Commission and the prototype was
rolled out 102 days after contract sighing and was first flown on 26
October 1940. They were first used by the Royal Air Force and from
late 1943, were used by the USAAF's Eighth Air Force to escort bombers
in raids over Germany,
I can find no evidence that the Vertical fin was offset in any manner
and I do know that the late model fuselages and canopies required
addition of a dorsal fin to increase lateral stability.
The report I quoted was prepared by the AAF Flight Test Division at
the request of the Production Section, Procurement division, to verify
the supplier's figures.
The stated conclusion was that "control and handling characteristics
of the P-51H are good under conditions tested with the exception of a
tendency to hunt directionally at indicated speeds above 400 MPH.
(this by the way is typical of a plane with a marginal amount of
As for 20 year olds, I know of no military airplane that performance
was dummied down to meet the abilities of inexperienced pilots. Quite
the opposite in fact, they are designed to meet a need specified by
the Military and in quite a few cases that results in aircraft that
are distinctly "Twitchy". The F-100A, for example, officially entered
USAF service on 27 September 1954 with 479th Fighter Wing at George
AFB, CA. By 10 November 1954, the F-100As suffered six major accidents
due to flight instability, structural failures, and hydraulic system
failures, prompting the Air Force to ground the entire fleet until
February 1955. Does that sound like an airplane designed to be flown
The F-51 did not have a movable horizontal stab. A trim tab will
generate more force as air speed increases.
The Reno P-51s, at least one that AOPA Pilot magazine carried an article
about, have the vertical fin re-aligned as I described. The article
specifically said that the stock airplane was tamed so as not to kill
new pilots, and the Reno P-51s are re-rigged for less drag and maximum
I think the same article also says that the racing engines remain
basically stock. They already can produce more power than their metal is
capable of containing.
Do I need to find that magazine? I really don't want to search through a
4-foot tall stack of magazines.
It's an old report.
The need wasn't top speed. They were designed to perform as well at 200
mph as at 400 mph. Pilots racing them today don't care about much of that.
All horizontal stabilizers are movable! Take out rivets, cut, bend, and
put it back on in a new position. Even the famous air scoop under the
P-51s belly is movable. The Galloping Ghost's was moved somewhere, I
can't see it in any pictures.
Yeah, again, although he protested loudly about it, he didn't read the
post he responded to.
Nobody SAID the stab was "movable", only that its incidence angle was
set; set by modification, not by "articulation".
Any aircraft can have modifications. I wonder if he thinks the incidence
angle of the stab (or wings, for that matter) was just accidental?
I helped a friend modify a DC3 for export (he did one about every seven
months). I'm not an A&P, but I'm an aircraft "groupy" and always willing
to throw in some grunt labor on an interesting project.
Before we were done, we'd changed a whole lot of how the airframe worked,
including re-bracing and re-framing the starboard side of the fuse,
carving a 10' wide cargo door in the side, and moving numerous
components, including electrical and hydraulic systems. We didn't move
the vertical or horizontal stabilizers, but it's pretty apparent how one
would go about it.
I also helped another friend rebuild an SNJ (got to fly it, too! <G>).
That project was almost a complete un-skin job. There was all kinds of
corrosion in load-bearing structures. It took a while. And while he was
at it, he made mods... <G> Any aircraft can be modified, even some of
those "glass slippers" like GlassAirs or Rutans.
On Sun, 25 Sep 2011 16:38:44 -0500, "Lloyd E. Sponenburgh"
And EVERY modification, unless in Unlimited experimental class,
requires [aterwork up the yazoo - and on certified planes it requires
a "supplimental type certificate" for EVERY modification.
If exporting to the third world, one MIGHT get away without.
firstname.lastname@example.org fired this volley in
No... even with the market, one had to STC every change, because the
aircraft had to be flown "commercially" (that is, in pursuit of being
sold) in US airspace.
Dick had all the approvals. The inspectors would glide by about twice a
week, just give a cursory look, and sign off. Remember, Dick did this
for a living, and had all the mods pre-approved. So it wasn't like doing
On Sun, 25 Sep 2011 16:38:44 -0500, "Lloyd E. Sponenburgh"
So what? We once manufactured and installed the entire aft fuselage on
a U-10 that had been run into by a truck at Nha Trang. We removed the
floor from the cargo compartment of a C-47 gunship and replaced all
the supporting structure after the crew complained about the mini-guns
But this is not to say that we arbitrarily changed the incidence of
either the wing or stabilizers.
And that's not to say that they "arbitrarily" changed anything, either.
But they could -- relatively easily, considering the scope of a complete
And I'll bet they did, because almost any aircraft can benefit from some
tweaking. But certainly not "arbitrarily". There's a boatload of
empirical data on how to make the P-51 a better racer. They've been
flying them in pylon circuits for a lot of years.
Not to argue but here is what I can find about the P-51's dorsal fin,
which was not fitted to the earlier aircraft.
Despite these modifications, the P-51Bs and P-51Cs, and the newer
P-51Ds and P-51Ks, experienced low-speed handling problems that could
result in an involuntary "snap-roll" under certain conditions of air
speed, angle of attack, gross weight, and center of gravity. Several
crash reports tell of P-51Bs and P-51Cs crashing because horizontal
stabilizers were torn off during maneuvering. As a result of these
problems, a modification kit consisting of a dorsal fin was
manufactured. One report stated: "Unless a dorsal fin is installed on
the P-51B, P-51C and P-51D airplanes, a snap roll may result when
attempting a slow roll. The horizontal stabilizer will not withstand
the effects of a snap roll. To prevent recurrence, the stabilizer
should be reinforced in accordance with T.O. 01-60J-18 dated 8 April
1944 and a dorsal fin should be installed. Dorsal fin kits are being
made available to overseas activities"
One specification that was part of the cockpit canopy modification was
" Because the new structure slid backwards on runners it could be slid
open in flight. The aerial mast behind the canopy was replaced by a
"whip" aerial which was mounted further aft and offset to the right."
True, but it is the report that the AAF produced at the time the P-51H
was accepted by the AAF.
Actually most of the modifications of the P-51 were to improve high
altitude performance or to allow better visibility. The original
Allison engines were actually more powerful then the later fitted
Packard-Merlin however the Packard-Merlin with their two speed
supercharger were faster at altitude.
Certainly one can butcher anything but it is a bit more complicated
then taking out rivets and bending. The horizontal stabilizer is a
major control surface and on these airplanes a fixed structure. The
cooling scoop is not movable, again it is a fixed structure. What you
are referring to was, I believe, the total removal of the cooling
scoop done to the Ghost as part of converting the cooling system to a
totally different type - the "boil off cooling system".
Correct, the British specified the Alison V-1710 ( 1475 H.P. @ 3,000
RPM) and "was first flown operationally by the Royal Air Force (RAF)
as a tactical-reconnaissance aircraft and fighter-bomber".
Not correct. Both the Allison and Packard-Merlin engines were
supercharged. The most powerful version of the Packard-Merlin V-1650-9
was actually of a lower horsepower (1380H.P. versus 1475H.P.) then the
earlier Allison. The difference was that the Packard-Merlin had a two
speed supercharger which allowed better performance at altitude then
The first airplane fitted with the Merlin engine was an RAF test craft
and first flown on 30 April 1942.
I give. I've flown
Lived on three airports.
Soloed on 16th birthday.
VIP pass for CAF
And have heard countless flying stories from;
Small home built race pilots
We use to modify aircraft including
& I've use to grind cranks for a FAA repair station.
Also have flown in bad weather, fogged in, running on fumes and lost
(Dad was cheap and used road maps or just water tower names.),
aerobatics (day & night), flown under power lines, engine failure, and
even snuck-in to an international airport at night without radio,
instrument panel lights, or navigation lights (electrical failure and
runway light down at our airport (typical).).
So, most if not all planes have a metal tab on each control surface
that is bent so that the controls are neutral in flight. Some aircraft
have adjustable trim controls in the cockpit which are adjusted for
load, prop settings, RPM, navigation, weather, ect. The most I've ever
seen is in a Staggerwing Beech. The trim is used mainly to get the
plane to fly straight without any input from the controls, because all
airplanes pull to some direction due to imperfections in construction
or modifications down to as simple as new antennas to unlimited race
I tryed to back out of this conversation cause I just don't know the
P-51 and the over powering of one. Matter of fact I don't think I've
ever seen the cockpit of one, I'm guessing it has a yoke instead of a
stick. Anyhow, you quote that the plane was (jacked-up my terminology)
trimmed, one permanent and one adjustable for the elevator and the
adjustable took a flight.
In my experience all simi-stable aircraft should fly straight and not
trimmed so hard that it causes black-out G-forces if a tab takes off.
Also, this type of plane took 20mm hits in the war. I would venture a
speculation (after your info.) that all the planes in the race are
trimmed hard so that during the straightaways the stick is pushed hard
forward, because it is easier to push against the back of the seat
than to stand on the rudder and pull back around the pylons and thus
the plane would be in the controls neutral position in the turns.
I'm also not sure if the unstableness of loosing that part would
exponentially increase or it got jerked out of his hands or the cable
for that trim could have broke in the cockpit and the cable got
violently stripped through the fuselage and by all the cables for the
BTW, prop wash from these planes must be very violent.
You know your stuff alright.
But, for a moment, imagine what it would be like to fly any airplane
without a trim system.
The aircraft will be naturally trimmed to fly hands-off at ONE GIVEN SPEED.
So at any other speed, the pilot has to provide the control force to
maintain attitude (and thus airspeed)
Assuming we are trimmed for cruise - approach and landing are going to
You are overlooking the fact that as speed changes then so does lift
and drag and torque, in a propeller driven airplane, and center of
gravity changes dependent on load. There has to be some mechanism to
balance these forces.
These changes are rather large - air pressure at, say 500 mph, is
approximately 25 times that at 100 MPH. A control surface that is
adequate at take off( say 100 MPH) would be 25 times too large at 500
MPH. Or to put it another way, a control surface that was adequate at
500 MPH would be 25 times too large at 100 MPH.
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