*From:* Rotary Engine <rotaryeng@earthlink.net>
*To:* AAA Put this in the To box <rotaryeng@earthlink.net>
*Sent:* Wednesday, August 31, 2011 8:00 AM
*Subject:* RV retractable landing gear


 All this is becoming too much of a project for what will likely be a
 one-time event for my plane.  If I plan to do any serious competition at
 Reno in future years.  I need: a new airframe with less drag and a higher
 Vne (most likely dedicated to racing), a 3 or 4 rotor, more time, and more
 money  :-)

 --
 David Leonard

 Turbo Rotary RV-6 N4VY
 http://N4VY.RotaryRoster.net <ttp://n4vy.rotaryroster.net/">
<http://n4vy.rotaryroster.net/ <ttp://n4vy.rotaryroster.net/">
 http://RotaryRoster.net <ttp://rotaryroster.net/">
<http://rotaryroster.net/ <ttp://rotaryroster.net/">


 I am thinking of putting retractable gear on the RV4. I am sure I will
get a
 lot of static from Van if he hears about it.  It is real easy to move the
 stock fuel tank outboard and add a root strake to house the wheel.  Much
 like a P51.  I will need to find a thiner wheel of some sort that will
fit.

 With Mike's skinny cowl it will look just like a P40. Van warns about
 putting fuel in the outer wing panels as he is worried about increasedthe
 polar moment of inertia about a vertical axis in a spin.

 What he is not telling you is he failed to put a strake on the RV vertical
 stabilizer like almost every other airplane in the world has includuing
 most all Cessna's and the P51.  When the aircraft is in a spin a strake
 generates a powerful vortex and low pressure area on the down wind sideof
 the strake tending to retard the spin.  That is easy to add to an RV as
 there is already a fiberglass fairing back there.

 I suspect a lot of RV'er would like to retrofit their RV's with
retractable
 mains.

 Paul Lamar


 Paul,  It looks like you could use a ball screw to operate the gear and
 have an access hole for a manual crank on the sidewall of the cockpit as a
 backup if the motor is unoperative.

 george grimes

What would work great is an RX8 electric rack and pinion.
The motor is hollow with the ball screw passing through it.

Paul Lamar

Hello Paul,

We run into this when looking to Harmon Rocket modifications, á la Bruce
Bohannon B-1

RV-4 Retracts:
http://www.vansairforce.com/community/showthread.php?tH338
<ttp://www.vansairforce.com/community/showthread.php?tH338">

RV-8 version, page 8:
http://www.vansaircraft.com/RVator/2008/3-2008-RVator.pdf
<ttp://www.vansaircraft.com/RVator/2008/3-2008-RVator.pdf">

Fuel tank schemes:
http://napwars.com/RV-8HTML/Fuel.htm <ttp://napwars.com/RV-8HTML/Fuel.htm">

Bruce Bohannon's modifed RV-4:
http://www.avweb.com/news/profiles/181769-1.html
<ttp://www.avweb.com/news/profiles/181769-1.html">

The idea was to make a "Cosmo Rocket" on basis of Harmon Rocket 2 and
twin-turbo 20B, and use it as "Vertical Drag Racer".
With 500-700 Hp, climb rate would be just insane :)

To use that as a Reno racer is possible too, but Vne is rather
limiting - even with HR2/HR3 wing.

Cheers,
Petri


Thanks for the links Petri. Can you get the attached pictures from
the Bohannon link? My browser is having problems with those.

It all depends on how far you want to push VNE. Most of these
airplanes, where it is not paying off, are 180 HP or below and
flying near VNE.

Dave Anders went 256 MPH in his 250 HP Lyc RV4 with a constant speed
prop. My ex hangar neighbor Tracy Saylor went 237 MPH in his Lyc RV6 in
the Sun n Fun 100.  Also with about 220 HP and a metal constant speed prop.

Allen Tole Went 238 MPH in the Sun n Fun 100 with the early Power Sport
rotary p-port powered RV3 or RV4 I forget which. Steve B?

The dynamic pressure at
250 MPH is 162 pounds per square foot compared to 104 at RV VNE
of 200 MPH. Obviously there is more safety margin in there than Van
claims.

One guys weight estimate of 250 pounds additional is too high.
Don't forget one loses the weight of the standard gear.

However when testing I recommend a jettisonable canopy and a parachute :)
Just in case Van is right :)

I also considered a whole new carbon fiber thinner, tapered wing along with
the retract :)

Paul Lamar



Paul,

just my two cents here, but get the plane flying and then maybe think
about doing mods on it. Building a thinnner wing would be the best route
to higher top speeds, but just how fast do you need to go? I think that
if you are trying to showcase the Rotary engine, most people would
realize it's performance capability when they can compare apples to
apples, ie, a standard RV-4 but with a rotary engine compared to a
similar RV-4 but with a Lycosaur.

By the way, if I may ask, what was the purchase price on Mike Will's RV-4?

Brian Trubee

It is flying but I am not. I have to get some RV time to satisfy the
insurance company. Dave Leonard offered but he is committed to Reno.

I have some time scheduled with Mike Seger but not until the third
week in Oct. I am still looking locally.


I got it for a song as I convinced the owner he would get nothing for
the firewall forward :)

I'll be doing a lot of mods before the retract. 2.85:1 gear box and
p-port are at the top of the list. I am not entirely happy with the panel
as IMHO it needs a steam gage airspeed indicator. Right now all it has
is an RMI for air data.

Paul Lamar