*From:* rotaryeng <rotaryeng@earthlink.net>
*To:* AAA-rotaryeng <rotaryeng@earthlink.net>
*Sent:* Monday, September 30, 2013 10:11 AM
*Subject:* Tricycle gear RV4



What do all you guys think of converting my RV4 to tricycle gear?

I have been told to wheel land it at 80 MPH.

That is a field length penalty and a much worse crash if you screw
up.

As I understand it they are dangerous in cross wind landings. I have
a friend with one that refuses to fly under sever cross wind
conditions.

Paul Lamar

It's not the beginning of April already is it ?

John


No john I am serious.  I have already spent $1000 with some jerk up
in Oregon trying to teach me to wheel land at 80 MPH.

Actually most of the time was spent  doing 360's just  under the
overcast and just above the trees like I needed to do that :)

When a tail wheel airplane first touches a paved runway with any
cross wind component at all the side force is ahead of the CG and by
any definition that is severe instability.

Tails wheels were designed back in the days when dirt air fields were
2 miles square and you could always land into the wind. Also the
coefficient of friction of  rubber tires on dirt or grass is much
less than on pavement.

I don't want to be put in position of either running out of gas or
landing in a cross wind with a tail wheel.

Paul Lamar




I learned to fly on a C120 and loved it. That one you could wheel
land or 3 point land. The 3 pointer landing actually happened in a
fairly short distance as we were taught to try and touch the
tailwheel down 1 second before the mains so you didn't touch mains
first and set up a bounce. Worked like a charm and its the same
technique as landing the tricycle just that you hold it off a bit
higher and a bit longer. Touchdown speed was lower than a wheeler
landing due to the high angle of attack at touchdown. Are you not
supposed to 3 point land a RV4? All serious short field planes with
tail dragged config seem to be able to land in a reasonably short
distance so I guess they 3 point land it,

Alex

Touching down on a locked tail wheel should work great. Maybe I
should

focus on finding or making a locking tail wheel.


Paul Lamar


Dear Mr. Lamar:

I would check with the Kit manufacturer and ask IF they have any
information regarding landing a Tricycle Gear RV4 in crosswinds. As
they offer a Tricycle Gear option, they should have a chart or
information about how it handles in crosswind landings, etc. that
should be in the aircraft manual.

I would also ask the Kit manufacturer IF they could send you the name
and addresses of several of their customers that have and fly a Tri
Gear RV-4s. I would contact those individuals. I am sure Tri Gear
RV-4 owners and operators could give you a lot of information based
on experience how the Tri Gear RV-4 handles in cross winds.

I would also check on installing Vortrice Generators on your
airplanes wings and tail to improve handling of your ariplane at low
speeds.

All My Best

Brannen Sanders


http://www.vansairforce.com/community/showthread.php?t=29562
<http://www.vansairforce.com/community/showthread.php?t=29562>

"The 8 has a larger rudder and longer fuselage and stiffer gear, is
heavier with different crosswind manners. To answer your question, in
my RV4 I used 20 knots max direct cross using a wheels landing, wing
low on touchdown technique. Any more and it's gets squirrley when you
lower the tail as the fuselage blanks alot of the rudder.The Rocket
with an RV4 rudder is even more pronounced. Most production
taildraggers use 17 knots direct crosswind as a limit. I asked a FSDO
guy once about that and he said that years ago all of the
manufacturers got together and agreed on a number, the insurance
companies liked it and there it was, 17 knots. Your mileage may
vary..."

"Rob Ray 1500 Hours RV4 HR2"

So apparently the rudder is blanked and that is why they insist on
wheel landings.

Back to nose gear :)

Paul Lamar

If I remember correctly wheel landings were done only a few MPH
faster than full stall landings. Used to get good control with rudder
and aileron, perhaps one brake in a cross wind. People that do it, do
it all of the time. Just to keep a keen edge on that tool. If you
cannot stay on the centerline during approach with bank and rudder,
you need to use a different runway, or airport.

You are not landing at 80 MPH. You are flying across an airport with
the wheels on the ground. That would be a low pass. Just get in some
slow time in a Champ or Cub and an old instructor. You just cannot
beat conventional gear for getting in and out of short fields.

I got stuck out in a cross wind and low on fuel over a paved airport
that had gas. I could not stay over the runway in my BC12D, so I
landed on the turn around circle at the end right into the stiff
wind. A couple of boys came out and clipped a rope into the tie down
ring on the right wing and walked me to the fuel pumps.

Lynn E. Hanover

The airplane is finished and flying. Since the tail is blanked at 3
point landing angles of attack perhaps vortex generators on the
canopy and fuselage sides would help.

A larger rudder with more area at the bottom would also help. The
rudder is structurally weak anyway and prone to flutter at speeds
over 200 MPH. We considered making a new balanced one out of carbon
fiber to stop that. The stock RV4 rudder is not balanced. The
balanced part at the top would help.

Van should be doing this.

A tall wheel faring that looks like a rudder would also help.

Paul Lamar

Paul, 80 mph seems pretty fast for an RV4.  Are the flaps down?

Helio aircraft were available in both tailwheel and trigear
configurations.  Most operators prefer the nose wheel.  It is easier
to control and actually takes off a little quicker because of the
level attitude during the take off run.  However, very rough runways
work better with a tailwheel, as the main gear are quite a bit
stronger.  The nose wheel is prone to collapse on a rough surface.

The Helio had the most pronounced crosswind challenges I have ever
met.When approaching at 45 mph, a 15 knot crosswind required a 30
degree crab angle.  With the mains well forward, to prevent nose over
in very soft terrain, quite a lot of weight on the tailwheel, and the
slow speeds, the plane could be very difficult to reign in, once the
nose began to wander.  The factory solution, early on was to castor
the main gear.  This worked quite well, but could feel a bit goofy as
you land, still crabbed 20 degrees into the wind.  Very difficult to
taxi until the wheels were locked again in place.  A guaranteed crash
if one main gear castored and the other stayed locked--a lot of
pilots had the heebie jeebies over it.  When production resumed in
the eighties, the factory solution evolved to a locking tailwheel.
Very simple pin, extended through a hole in the tailwheel steering
shaft.  Like this, a three point landing is almost a non event.
Wheel landings in a Helio are a dicey affair, mostly done when the
pilot is showing off, just to prove he can do it.  Nothing wrong with
three point, 100% of the time.

A hangar partner of mine recently porpoised his RV6A (trigear) on a
grass runway in Idaho.  The nosewheel folded back up into the cowling
and drove his propeller into the dirt.  He is now rebuilding the
plane with a tailwheel.

My Pitts Model 12 must be landed three point every time, due to the
size of the prop.  I have landed in some very powerful crosswinds
without much issue.  Since you are concerned about it, figure out a
tailwheel lock for the RV4.  Set it up to engage whenever the stick
is held all the way aft (like a P51) and make three point landings.

I would not recommend a nosewheel for the RV4.  Get some better
training.  Yes, tailwheel configurations are old, but they have
remained in play this long because they actually work pretty well. If
you are worried about an engine out landing into a field, the
tailwheel would be a better choice.

Lewis Bjork


Yea you drive it on.

That jerk up in Oregon never told me about the tail blanking. If he
had I might have tried harder. He was a friend of Van's and Van does
not like people talking about his airplane's design short comings. If
it were me I would come up with a retrofit fix and sell it. Maybe the
lawyers are controlling the situation and to come up with and sell a
fix is an admission of a design flaw.

Beech stone walled the V tail doctor killer for years until some body
lived through a tail coming off and proved it. Beech would just say;
"don't exceed the VNE".

The truth of the matter was it was all too easy to exceed the VNE in
IMC  in a V-tail. Put the nose down a bit and bingo you are past
VNE.

You can put the nose straight down on a C182 and it won't go past VNE
:) Clean airplanes designers have to design the tail with higher VNE
margins.

I have landed down in  Baja many times in the C182 with a 30 kt cross
wind. Slip and crab :)

Paul Lamar


Have you looked at the Kasper Wing winglet controls. That would take
the pressure of the vertical stabilizer.


Peter Duffecy

No :)

Paul Lamar



Google Witold Kasper. Check out his winglets.

-- Peter Duffecy


The RV4 is not a flying wing. I have no interest in flying
wings. They tumble.

Paul Lamar

   For what ever its worth:
   I'd get some old tail dragger pilot to fly with you a bit. He can
tell you if the 4 is hard or easy to land in cross winds. Some tail
draggers are harder to land than others.  If ihe 4 is hard, then change
it.  If not hard, then make sure you have real good brakes and you'll be
okay.
   You can learn wheel landings.  But it will always be a little
scarier in a tail dragger in my experience.  I'm not real experienced
pilot, but had a Bonanza and later Cess 180. Flew new 182 one month (100
hrs) while Bonanza getting fixed. Probably 800 hrs in Bo and 300 hrs in
180.  The only plane I could fly to landing was the Bo.  182 you guide
around and land like a box kite.  Wheel landing 180 a little better than
182 for
   feeling like flying instead of guiding.  But, I didn't have any tail
   dragger time when bought 180.  So I was doing 3 pt landings for a
year thinking they were wheel landings:-)  Rode with another guy in his
180 and he did wheel landing.  I asked what was that and how did be for
it:-). He told me.  I learned on my own in my plane and things got way
less scary.  But my old brakes would get hit and peddle would go to
floor soon if diddnt get slowed down before brakes failed.  Ran off
runway few times but never wrecked it. Clevelands would have changed all
that.

   All that to say, if RV4 is not a bad tail dragger to land, you can
handle it.  Just make sure you have real good brakes to keep it running
straight after you lose your rudder.  You'll be fine. Only reason yo
have a tail dragger at all is to land on rough ground so don't break
nose wheel off and keeps prop higher for less gravel. So if you want to
land in a field on purpose or in emergency you can. If crosswind too
high to land on runway at airport, you can always land into wind there
with tail dragger someplace that you couldn't with nose wheel without
breaking it off or damaging prop.
   But get an old crusty real pilot to check RV and show you wheel
landings.

   Van

   I got the rear rudder pedals kit so I will put that in shortly.

   Paul Lamar


   Paul,
   You might want to have a more experienced tailwheeler put some time
on it for you. Its not a good idea to make a bunch of changes until you
are certain there is a problem.

   Milo

   I have talked to enough people about it so far. I am going to try a
Raven locking tail wheel and disconnect
   the rudder from the tail wheel. Steer with the brakes if need be.

   Paul Lamar



I bet that would work real good so long as you can unlock to spin
around.  Brakes steer fine.
Van

Very popular in Pitts circles.
I feel very confident I can plant the locked tail wheel first. That should
keep the airplane going straight for the first few critical seconds.

One still has the rudder independent of the tail wheel.

A local friend of mine is a Pitts driver and competitive aerobatics pilot.
He has given me bi annuals in the past. I am sure I can get him
to go flying with me when I get the rear cockpit rudder peddles installed.

Paul Lamar


   Don't try it in a cross wind:-).  Learn wheel landings.  They are
easy and can do them at whatever speed works for conditions. When you
need the locked tail wheel is when the tail stops flying and drops to
ground no matter how hard you push forward on stick. If still rolling
fast enough, for rudder to overcome the crosswind component, you'll have
control to keep it straight even with tail unlocked.  Its when you lose
your rudder sometime after tailwheel is on the ground, ie  crosswind
overcomes the rudder control and trys to weather vain you into the
wind-that I think locking tailwheel will help.  To weather vain with
wheel locked, it would have to skid sideways.  If wind blowing hard
enough, it would skid, but would take stronger crosswind.  With good
brakes, you can get on downwind brake and keep it straight.  I crosswind
so bad you can't do it, just land into wind on the grass.  You'll
probably only be crawling when you touch down if wind blowing that hard.
 Even with wheel landings, you have to land on the upwind wheel just
like with try cycle gear in crosswind.  That's darn hard to do with a
tail dragger when trying to do a full stall tail down first. Believe me
I tried it for about a year in my 180 before I knew what wheel landings
were:-). And that was in Wyo and Mont where wind always blows and at my
two home airports at 7000+ and 6000+ feet.  Was real lucky I never
wrecked it.  Just my two cents.  I'm sure not experienced enough to be a
great authority.  Never flew low wing dragger but bet I'd like it better
than high wing dragger.  I loved my Bonanza in crosswinds-taking off or
landing.  Seemed like uiy could keep that wing down so wind didn't get
under it like when I flew 182. Remember taking off in Canada somewhere
with direct crosswind blowing like hell.  Almost afraid would tip over
just taxing. Really wished u was flying the Bo right then.  Thought sure
when I left the ground, wind would flip me:-).
   Van







Paul,

They never made a tricycle RV-4, so any conversion would be a one-off.
Really not worth it.  Easier to build an RV-8A  or RV-6A.

80 mph is way too fast for that plane, especially solo.  That might be a
workable number with a gross weight and aft CG.

IMHO, a tricycle would not be any better in crosswinds for the RV-4.
Any RV is easy to handle up to about 15 kts crosswind component.  If it
is higher than that, don't fly or land somewhere with a proper runway
orientation.

I agree that you should get up to speed in a certified tail dragger,
transition should be easy.  Also, spend a lot of time taxiing yours around.

My offer still stands to fly it for you some to make sure things check out.