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Re: Flats?

Larry Severson
 

You are correct, an airplane does get lighter on the wheels, the camber
changes, etc. However, If built to plans the Q2xx has 0 camber only at
liftoff speed; at any lesser speed there is some load on the wheels, some
flexion of the canard, some negative camber. The amount of negative camber
varies with the load and airspeed; the risk of ground loop varies with the
load, airspeed and groundspeed.
Agree; however, I suspect that much of the problems stem from the fact that many of the planes have flat bottom (auto/cart) tires. Planes typically have rounded treads to reduce the camber impact. The surface orientation of the tread does not change as the camber is modified by existing conditions. The flat treads will carve a path, like skis on snow, when the camber changes due to change in weight or bounced landings. This WILL cause a turn (and probable GL).

Negative camber can lead to a positive feedback situation which can be
uncontrollable. (Tailwheel airplanes are prone to ground loops because the
center of gravity is behind the main gear and this also promotes positive
feedback) Positive feedback means whatever change is happening tends to
increase; Negative feedback means whatever change is happening tends to be
damped out.
All true; but again, my plane has rounded A/C type treads. With the exception when I have gotten one brake dragging, it has tracked as straight as any plane I have ever flown.

For anyone who insists on flying with flat treads, I would go with the Gall arrangement.


Larry Severson
Fountain Valley, CA 92708
(714) 968-9852
larry2@...
Re: Flats?

Mike Perry <dmperry1012@...>
 

Larry:

You are correct, an airplane does get lighter on the wheels, the camber
changes, etc. However, If built to plans the Q2xx has 0 camber only at
liftoff speed; at any lesser speed there is some load on the wheels, some
flexion of the canard, some negative camber. The amount of negative camber
varies with the load and airspeed; the risk of ground loop varies with the
load, airspeed and groundspeed.

Negative camber can lead to a positive feedback situation which can be
uncontrollable. (Tailwheel airplanes are prone to ground loops because the
center of gravity is behind the main gear and this also promotes positive
feedback) Positive feedback means whatever change is happening tends to
increase; Negative feedback means whatever change is happening tends to be
damped out.

This is from Mike Dwyer's letter on the subject, Q-List archives 12/28/01:
I assumed that QAC wanted 0 camber at gross when I built my plane (later
known as the Gaul alignment). In the initial taxi and flight tests
another tail dragger pilot said "It handles like it is on a rail", I
agreed. After 15 years the canard sagged enough that I had a fair amount
of camber. See: http://www.geocities.com/CapeCanaveral/Hall/1653/r2.html
It slowly (over the years) became less easy to handle on the ground. I
have now put the camber back to 0, had tons of trouble with tire clearance
and the QAC plans brake install. The handling is great again. 2" toe
out, 0 camber at gross, reflexer, one handle brake, standard Q200 built to
plans.
Mike Perry


At 09:30 PM 1/3/2007 -0800, Larry Severson wrote:

At 06:07 PM 1/3/2007, you wrote:

To Larry Severson re Gall wheel alignment:

1) What Dave Gall wrote makes sense to me intellectually

2) What he wrote fits with my experience with Dune Buggies (my mis-spent
youth)
The dune buggy does not get lighter on the wheels as the speed
increases. An airplane does!

Larry Severson
Fountain Valley, CA 92708
(714) 968-9852
<mailto:larry2%40socal.rr.com>larry2@...
another trick

Larry Severson
 

Miguel Chabolla has come up with the solution for us senior pilots attempting to go cross country, a powered relief tube.
requires:
1. auto window washer pump
2. momentary switch (pump as long as it is pressed
3. 1/4 in. alum tube bent to face aft.
4. "lady J" potty fixture (available AS)
5. sealant to link fixture to tube going to the pump

Larry Severson
Fountain Valley, CA 92708
(714) 968-9852
larry2@...
Need help to download Q2 Plans

gideon_grobbelaar <3yp@...>
 

Hi to All
Name is Gideon Grobbelaar, Living in Phalaborwa, South Africa...I am
planing on baying a Q2 from Mike Wright, From East-london in South
Africa. So I tride to dowload the plans from
http://www.finleyweb.net/default.asp?id=141, but someting seemed to
gon wrong now I canonot find the page any more
Need help to download Q2 Plans

gideon_grobbelaar <3yp@...>
 

Hi to All
Name is Gideon Grobbelaar, Living in Phalaborwa, South Africa...I am
planing on baying a Q2 from Mike Wright, From East-london in South
Africa. So I tride to dowload the plans from
http://www.finleyweb.net/default.asp?id=141, but someting seemed to
gon wrong now I canonot find the page any more
Re: Flats?

Larry Severson
 

At 06:07 PM 1/3/2007, you wrote:

To Larry Severson re Gall wheel alignment:

1) What Dave Gall wrote makes sense to me intellectually

2) What he wrote fits with my experience with Dune Buggies (my mis-spent
youth)
The dune buggy does not get lighter on the wheels as the speed increases. An airplane does!


Larry Severson
Fountain Valley, CA 92708
(714) 968-9852
larry2@...
Re: Flats?

Mike Perry <dmperry1012@...>
 

To Larry Severson re Gall wheel alignment:

1) What Dave Gall wrote makes sense to me intellectually

2) What he wrote fits with my experience with Dune Buggies (my mis-spent
youth)

3) What he wrote fits with Mike Dwyer's experience with the Q2: "[I
ground looped]. . . when the wheel camber got so bad I couldn't stop
it." see his website, refinishing, bottom of page 2/top of page 3:
http://www.geocities.com/CapeCanaveral/Hall/1653/re2.html

So, what's your problem with the Gall wheel alignment?

Mike Perry

At 08:06 PM 1/2/2007 -0800, Larry Severson wrote:

[snip]

AND the Gall Wheel alignment.
I personally disagree with the whole theory behind the Gall
alignment. But to each his own.

My gear are set up 0/0, and without a dragging brake, I couldn't ask
for better. My plane tracks straight as an arrow.

If you have a hard landing, you will get some splay of the gear; but
if you have the round bottom tires, it will have no impact. However,
if you fly it down to the runway, a hard landing should be rare. In
either case on a normal situation, above 50mph, there is very little
weight on the wheels, and thus no change in camber than an unloaded wheel.

Larry Severson
Fountain Valley, CA 92708
(714) 968-9852
<mailto:larry2%40socal.rr.com>larry2@...
Re: Flats?

Larry Severson
 

I'm guessing but unsure if you are referring
to the Drag brake when you say "dragging brake"
absolutely NOT

and not referring to a
sticky brake problem?
Yes I was.

Also if this is the drag brake, I wasn't sure if you were implying that
this is counter productive regarding directional stability on the
ground, or a good thing to have.
Good thing to have -> no impact on directional control.

Then I wondered if they were even a
fitted mod on a traditional Q 2
Yes


Larry Severson
Fountain Valley, CA 92708
(714) 968-9852
larry2@...
Re: Flats?

Doug Humble <hawkidoug@...>
 

Trevor, I believe Larry is referring to a sticky brake, not a "drag brake". The air brake I think your may be referring to is useful in slowing down this otherwise slick bird, but not absolutely necessary. Many high hour pilots, like Sam Hoskins, have done the Gall Wheel alignment and report improved handling on the tail dragger.

Doug "Hawkeye" Humble
A Sign Above www.asignabove.net
Omaha NE
N25974

----- Original Message -----
From: twkte
To: Q-LIST@...
Sent: Tuesday, January 02, 2007 11:42 PM
Subject: [Q-LIST] Re: Flats?


> Fantastic, unless you have a dragging brake.
> Larry Severson

Hi Larry, as a newcomer, I'm guessing but unsure if you are referring
to the Drag brake when you say "dragging brake" and not referring to a
sticky brake problem?
Also if this is the drag brake, I wasn't sure if you were implying that
this is counter productive regarding directional stability on the
ground, or a good thing to have. Then I wondered if they were even a
fitted mod on a traditional Q 2 as I only came across it as a result of
going into the Tri-Q setup?

Trevor
Re: Flats?

twkte <spilligan@...>
 

Fantastic, unless you have a dragging brake.
Larry Severson
Hi Larry, as a newcomer, I'm guessing but unsure if you are referring
to the Drag brake when you say "dragging brake" and not referring to a
sticky brake problem?
Also if this is the drag brake, I wasn't sure if you were implying that
this is counter productive regarding directional stability on the
ground, or a good thing to have. Then I wondered if they were even a
fitted mod on a traditional Q 2 as I only came across it as a result of
going into the Tri-Q setup?

Trevor
Re: 2007 Fly ins

Panzera <panzera@...>
 

I'm leaning towards the first weekend in May.

Pat

-----Original Message-----
From: Q-LIST@... [mailto:Q-LIST@...] On Behalf Of
Mike Perry
Sent: Tuesday, January 02, 2007 7:40 PM
To: Q-LIST@...
Subject: [Q-LIST] 2007 Fly ins

Anyone know proposed dates for the 2007 Alternate Engine/Tandem Wing Fly-
In?

(If no date chosen yet, 8 April is Easter)

Mike Perry






Quickie Builders Association WEB site
http://www.quickiebuilders.org


Yahoo! Groups Links
Re: Ground Loops - final!

Larry Severson
 

On my first flight attempt, I lost power at the point of T/O. I pulled my throttle and grabbed my brake (single at that time) handle. The plane swerved to the right off the runway into the weeds. I broke my canard 18 inches inboard of the left gear when I crossed a rut between the runway and the taxi way. The rut was not deep, but it did cause a strong side load. The rut came from a vehicle driving in the dirt area during a period of rain. The plane was going in a wide right turn until it hit the rut. It then made an abrupt left 45 degree turn, went up on its nose, hung there for a bit before slamming down. The canard was broken, so was the prop, tail cone, and tail wheel shaft. Under no circumstance will I accept a deviation off the runway in the future if I can avoid it. I will GL every time.

Larry Severson
Fountain Valley, CA 92708
(714) 968-9852
larry2@...
Re: Flats?

Larry Severson
 

Q-2s aren't too popular around here -- usual reaction: "Do you know how
fast that thing flies on final?"
80mph, hold off until it touches. Since the seat, when the plane is on the ground is about the height of a chair, getting down to 4 inches is easy. Remember, ground effect starts at 1/2 of the wingspan above the ground. Given the tail dragger setup, the plane is a snap to land for those who take it down next to the ground.

"Do you know about the ground
handling?"
Fantastic, unless you have a dragging brake.

et cetera, et cetera. Hence my interest in the Jim-Bob 6-Pack &#92;
Beneficial.

AND the Gall Wheel alignment.
I personally disagree with the whole theory behind the Gall alignment. But to each his own.

My gear are set up 0/0, and without a dragging brake, I couldn't ask for better. My plane tracks straight as an arrow.

If you have a hard landing, you will get some splay of the gear; but if you have the round bottom tires, it will have no impact. However, if you fly it down to the runway, a hard landing should be rare. In either case on a normal situation, above 50mph, there is very little weight on the wheels, and thus no change in camber than an unloaded wheel.

Larry Severson
Fountain Valley, CA 92708
(714) 968-9852
larry2@...
2007 Fly ins

Mike Perry <dmperry1012@...>
 

Anyone know proposed dates for the 2007 Alternate Engine/Tandem Wing Fly-In?

(If no date chosen yet, 8 April is Easter)

Mike Perry
Ground Loops

Mike Perry <dmperry1012@...>
 

This is from the Q2 Pilots Manual put out by QAC:

MINIMIZING THE GROUND ROLL ON LANDING

Under normal conditions, to minimize the landing ground rollout, touchdown
at the minimum speed, maintain directional control with the tailwheel , and
apply brakes until the tailwheel lifts clear of the ground. A further
reduction in ground rollout can be obtained by shutting the engine off
using the ignition switch.

If, after accomplishing these items, the remaining space available for
stopping is still insufficient, you may elect to intentionally groundloop
the aircraft. To do this, apply full rudder and wait patiently; the
aircraft will turn in a circle of ever decreasing radius while lowering the
speed. After about 180-270 deg. of turn, the aircraft will stop. During
flight testing, this maneuver was accomplished without damage to the
aircraft. No tendency to tip over was evident. Carefully inspect the
entire airframe after a groundloop.

CAUTION: This maneuver is not recommended as a normal operation because
of the very high loads imposed on the airframe.

Note the comments on airframe loads; also note this is without differential
brakes.

Mike Perry
Re: Flats?

Mike Perry <dmperry1012@...>
 

Thanks for the update. If he took off from around Gallup or Albuquerque
then eastern Oklahoma would have been about 3 hrs flight time but on the
far side of the Sangre de Christos, hence flying at a higher altitude.

I heard most of the story when I bought the kit I'm working on now --
Richard wanted to buy the LS-1 canard from this kit for his repair but Ross
would only sell if Richard took the whole project. They never made a deal,
so now I have a project.

Q-2s aren't too popular around here -- usual reaction: "Do you know how
fast that thing flies on final?" "Do you know about the ground
handling?" et cetera, et cetera. Hence my interest in the Jim-Bob 6-Pack
AND the Gall Wheel alignment.

Mike Perry

At 10:19 PM 12/31/2006 -0600, Sam wrote:

I think it was Tahlequah, OK and a Stinson.

_____

From: <mailto:Q-LIST%40yahoogroups.com>Q-LIST@...
[mailto:Q-LIST@...] On Behalf Of
Mike Perry
Sent: Sunday, December 31, 2006 9:27 PM
To: <mailto:Q-LIST%40yahoogroups.com>Q-LIST@...
Subject: RE: [Q-LIST] Flats?

Following up on Sam's post:

The California flyer was Richard Shapley who lives about 45 miles from me;
I've spoken to him and also to other local EAA guys who knew him at the
time. He had about 700 hours on his Q200 at the time of the
accident. Here is my understanding of what happened:

Richard either took off from here with a tire leak or developed one en
route to Oshkosh. He hoped to get to Oshkosh and replace the tube before
coming home. At each stop he would pump up the tire before takeoff and it
would be low on landing.

Crossing the Rockies (New Mexico I think) he flew higher than on the
previous legs. On landing the wheel locked up and he slid off the runway
and destroyed the canard. I'm pretty sure he hit a runway light, not an
airplane; otherwise the story is as Sam stated. The local speculation is
that by flying higher he increased the pressure differential so the tube
leaked more, but it may just have been a slowly worsening problem.

Several lessons here:
-- Don't ignore a known problem with landing gear
-- Flats can be a very serious problem

I think Richard could have saved the plane if he had differential braking
(toe or finger brakes), but he had only the plans single handle
brakes. This is of course pure speculation on my part.

Mike Perry

At 01:05 PM 12/31/2006 -0600, Sam wrote:

A flat on a conventional gear IS a major issue. I spend a lot of time
making sure my wheels and brakes are in good condition.

About 10 year back a venerable Q-200 flyer from California had a flat tire
on the way to Oshkosh. I don't remember it was taking off or landing. He
went off the runway and hit a parked aircraft. He was okay, the plane was
totaled.

Sam Hoskins
Re: Ground Loops

Richard Hole <rickhole@...>
 

My old philosophy prof said, "All generalities are false, including this
one."


If the gear housing is attached properly to the wing tip AND the
runway is greater than 50 feet, or you are on the side of the runway
away from the direction of the expected GL, it should be impossible
to hurt the Q. Of course, Murphy was an optimist!
Re: Ground Loops

Larry Severson
 

Larry,
I'd be a little more careful with the word never. There is always a way.
Earnest
If the gear housing is attached properly to the wing tip AND the runway is greater than 50 feet, or you are on the side of the runway away from the direction of the expected GL, it should be impossible to hurt the Q. Of course, Murphy was an optimist!


Larry Severson
Fountain Valley, CA 92708
(714) 968-9852
larry2@...
Re: Ground Loops

Richard Hole <rickhole@...>
 

A newcomers comment: this is a very useful thread. Please share your
experiences along with theories and analysis. Thanks.
Re: Ground Loops

Mike Dwyer <mdwyer@...>
 

I have done 2 ground loops (so far). One when the tail wheel broke off on a runway center thumper light and one when the wheel camber got so bad I couldn't stop it. Both were at around 50 mph. In both cases the plane turned 90 degrees to the left and quickly stopped. In both cases the plane continued basically down the centerline. In the first case the tail lifted about 4 feet and at the end of the loop it slammed into the runway and crushed the tail skin just forward of the tail fin. It stops real fast when going sideways.

The Q200 isn't the easiest plane to ground loop but it is the safest to ground loop. Given a choice of hitting the fence at the end of the runway or forcing a ground loop, I'm pushing the left rudder petal to the floor every time!

Have a Safe 2007!
Mike Q200 1000+ hours


larry severson wrote:

The fear of ground loops is correct when dealing with ME 109s and Piper Cubs. Wing tip mangling and even cartwheels can result. Narrow gear reduces the number of ground loops, but greatly increase the risk!

The bad news is that the Q, with its excessively wide gear, is easy to ground loop. The good news is that a GL will NEVER result in getting a wing tip or cartwheel. There is no safer plane anywhere when it comes to a GL. In fact, this factor can be a safety factor once it is fully understood.

Larry Severson
Fountain Valley, CA 92708
(714) 968-9852
larry2@...

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