REFLECTOR: Aerobatics: Rolling about a point
Jim Sower
canarder at frontiernet.net
Thu Feb 24 10:16:33 CST 2005
Scott,
I couldn't agree more. The last thing I said was "... don't do this at
home ..."
I probably should have emphasized it more ... Jim S.
Scott Baker wrote:
> Jim, Terry, All -
> This discussion about aerobatic flights in Velocity aircraft bothers
> me in the sense that -
> a) While strong, the aircraft is _not_ designed as an aerobatic aircraft
> b) Several Reflectorites are attempting to describe how to perform
> aerobatic maneuvers, when the absolute best advise is, "Go get
> aerobatic instruction, from an instructor that teaches aerobatics, in
> an aircraft that is designed for aerobatic maneuvers."
> c) (Jim) Your military training gives you the background and
> experience - but I don't think it's a good idea to coach someone to do
> 4-5'g maneuvers at an airspeed that is 40 Knots faster than Va and 10
> Knots faster than Vno.
> Aileron rolls in the Velocity are a lot of fun - and the aircraft
> certainly performs the maneuver with ease. My advise is, "Know what
> you are doing before you attempt to do it; know what to do if the
> maneuver doesn't turn out 'just right'; and also, do the maneuver
> without subjecting the aircraft to high stress (ala Bob Hoover's
> famous film footage of doing a slow roll in the twin Commander while
> pouring water from a pitcher into a glass).
> My 2-cents.
> Scott B.
>
> ----- Original Message -----
> *From:* Jim Sower <mailto:canarder at frontiernet.net>
> *To:* Velocity Aircraft Owners and Builders list
> <mailto:reflector at tvbf.org>
> *Sent:* Wednesday, February 23, 2005 8:52 PM
> *Subject:* Re: REFLECTOR: Aerobatics: Rolling about a point
>
> Terry,
> Aileron rolls in my experience are positive G maneuvers. A full
> acrobatic airplane can do aileron rolls quite nicely without
> negative G (for the most part - like except for demos of multiple
> multiple rolls with no altitude change). Like, by the time the
> airplane figures out that the nose should be dropping, you're not
> upside down any more. The problem with the Velocity is A)
> limited roll authority, and B) large lateral (rolling) inertia
> that has to be overcome result in painfully slow roll rates. One
> way to compensate for this is: start level at your entry speed
> (you mentioned 185 kias), yank in a lot of back stick (4-5G?) and
> snap your nose up 10* or more before you start the maneuver. You
> don't have to climb, just establish your velocity vector at least
> 10* up. Then put in all the stick and rudder you have. The swept
> wings of the Velocity will help with your roll rate to the extent
> you have positive G and full rudder. If you're heading uphill
> (even if your altitude hasn't changed yet) you are in a position
> to scoop out a good bit without losing all that much altitude.
> Starting anything remotely like level, the sorry roll rate and
> high inertia of the Velocity will cause you to scoop out so hell
> wouldn't have it, so be sure to be going smartly uphill when you
> start. Whatever else happens, once you start DON'T STOP (unless
> you fully intend to do a split-S).
>
> By way of perspective, military fighters do not have inverted fuel
> or oil. The ones I flew had around 10 sec of inverted fuel and no
> oil at all. A great deal of ACM maneuvering with swept wing
> fighters involves "rudder rolls" which as the name implies uses a
> lot more rudder than aileron. Demo planes (Blues, T-Birds, etc.)
> have very elaborate fixes to give them full inverted fuel and oil.
>
> By NO means do any rolls below 4000 - 5000 AGL until you've done a
> LOT of them at high altitude. Even when you do it as best the
> airplane is able to, it's so awkward and sluggish that it isn't
> even any fun.
>
> More better, take Alex's advice - do this stuff in an airplane
> that can do it right ... Jim S.
>
> Terrence Miles wrote:
>
>> Hey. Thanks Alex. I understand that explanation better. I know
>> I have lots to learn about carnards. I am filing your reply in
>> my "ops" box, but could do me this last favor?
>>
>> Let me say it all back to you. Let's just say that I am in
>> level, unaccelerated flight at 185 kts and 5000 feet. Let's also
>> say to hold all this constant, I need +2 pitch on my attitude
>> indicator. If I leave the power alone, then raise the deck angle
>> to +10, neutralize the elevator, and than apply full left
>> aileron, then you are saying that the carnard will continue
>> to pull me "upwards" (that is 90 degrees from a line defined from
>> cannard wing-tip to wing-tip.) ...so the to watch me from an
>> in-trail position I am sort of cork screwing thru the air?
>>
>> If I understood you right, can't this carnard factor be countered
>> with a tad of down elevator (and not zero G) so as to keep the
>> nose on a near constant spot on the horizon, and maybe roll-out
>> back wings level at something near my entry pitch angle of +2
>> with little altitude change?
>>
>> Regards,
>> Terry
>>
>> -----Original Message-----
>> *From:* reflector-bounces at tvbf.org
>> [mailto:reflector-bounces at tvbf.org] *On Behalf Of *Alex Balic
>> *Sent:* Tuesday, February 22, 2005 12:00 PM
>> *To:* Velocity Aircraft Owners and Builders list
>> *Subject:* RE: REFLECTOR: Aerobatics: Non center line rudder
>>
>> Hi Terry-
>> About the aileron roll maneuver - you need to think about the
>> difference in lift points on the canard vs. the standard
>> fixed wing- if you see these as arrows pointing straight up
>> from the fuselage, it is easier to understand - normally
>> these forces are fighting gravity- in the case of the
>> standard there is a single large lift vector centered right
>> around the center of mass, on the canard, there are two lift
>> vectors one in front, and one behind the center of mass. when
>> you flip the standard up side down, all you need to do it
>> change the angle of attack, and the lift vector goes through
>> the floor instead of the top of the fuselage. on the
>> velocity, you can not change the angle of attack to negative,
>> because it is not set up to have a negative angle of attack,
>> so even a simple aileron roll will be more like a barrel roll
>> because the lift vector of the canard will not go negative-
>> it is just like going through an aileron roll with constant
>> back pressure on the stick of a standard planform aircraft-
>> so if you are not careful, when you roll 180 and hesitate
>> because the nose is not going where you think it will, then
>> it tends to perform more of a split S. The Berkut company
>> had their demonstrator doing a lot of interesting things
>> (before it crashed) it could do loops, and some rolls too,
>> but the roll rate was probably double of the Velocity, so
>> they could get away with more.
>> Anyway, best to make some friends in the RV community so you
>> can go out on Saturday morning and get your fix- that is
>> pretty much what I have done!! I can't really think of any 4
>> place that beats the Velocity in cross country comfort- even
>> though the Lancair is faster, it is not as roomy or stable or
>> quiet......
>>
>>
>> Alex
>>
>> -----Original Message-----
>> *From:* reflector-bounces at tvbf.org
>> [mailto:reflector-bounces at tvbf.org]*On Behalf Of
>> *Terrence Miles
>> *Sent:* Sunday, February 20, 2005 12:32 PM
>> *To:* alex157 at direcway.com; 'Velocity Aircraft Owners and
>> Builders list'
>> *Subject:* RE: REFLECTOR: Aerobatics: Non center line rudder
>>
>> Alex,
>>
>> Thanks for the advice. Actually the RV8 was a contender,
>> but you freeze out your backseater (in my case wife) on
>> the cross country flights...which is my principal use. I
>> don't think the RV10 is stressed for aerobatics. My only
>> experience with acro is in a T-38 in 1968 doing about 300
>> kts. So it's been a while, and add to that I have
>> limited time in SEL recips. Sorry for sounding so
>> stupid. I am just trying to get an understanding of
>> accelerate/decelerate capabilities and more on the flight
>> characteristics of a carnard. I am getting the XL so
>> those rudders are way out there and don't work in
>> tandem. Thanks for your input. I get your point about
>> sustained level inverted flight is different with a
>> cannard design.
>>
>> I still don't think of an aileron roll maneuver as ever
>> going negative. It you start w/ the nose up +10 from
>> level I can't invision losing altitude either. About
>> the cuban eight...but I would want to execute
>> constant-heading half rolls without the airplane
>> fishtailing due to any possibly needed non-centerline
>> rudder inputs to compenstate for torque influences w/
>> larger throttle changes. Is this an issue? Have you got
>> a comment there? As a small aside, my Saturday acro
>> occasionss would not include any intentional neg g's!
>> Yuk. Thanks for the welcome and for getting back when
>> you have a minute.
>> Terry
>>
>> -----Original Message-----
>> *From:* reflector-bounces at tvbf.org
>> [mailto:reflector-bounces at tvbf.org] *On Behalf Of
>> *Alex Balic
>> *Sent:* Sunday, February 20, 2005 12:01 AM
>> *To:* Velocity Aircraft Owners and Builders list
>> *Subject:* RE: REFLECTOR: WANTED: Acro contacts
>>
>> Hey Terry,
>> Welcome to the reflector!
>> About the velocity doing aerobatics, the canard
>> design in general, and the Velocity in
>> particular does not lend itself well to any negative
>> G maneuvers due to the load being shared by both the
>> wing and the canard, in most other planforms, the
>> wing does all of the carrying, so if you want to go
>> inverted, you just need to fly the wing at a positive
>> angle of attack with the ground. If you try a roll
>> with the velocity, you might pull it off, some have,
>> but chances are, as soon as you go inverted, you will
>> find that there isn't enough down elevator to keep
>> the nose level, and the canard is going to pull you
>> really hard toward the center of the earth, and you
>> will end up doing an un-commanded split-s. If you
>> like doing Aerobatics, even Saturday morning style,
>> you would be better off in an RV which is a blast to
>> fly that way.
>>
>> -----Original Message-----
>> *From:* reflector-bounces at tvbf.org
>> [mailto:reflector-bounces at tvbf.org]*On Behalf Of
>> *Terrence Miles
>> *Sent:* Saturday, February 19, 2005 9:10 PM
>> *To:* 'Velocity Aircraft Owners and Builders list'
>> *Subject:* RE: REFLECTOR: WANTED: Acro contacts
>>
>> Hi,
>>
>> I should enjoy my ignoble status while it lasts.
>> I have the honor to
>>
>> be the very newest running nose, wide-eyed kid on
>> the block. The kit
>>
>> gets delivered in a month or so. In fact I
>> can't seem to get my own email out
>> (reflector at tbvf.org)
>> <mailto:reflector at tbvf.org%29> so I had to use
>> the reply function to get this on the Reflector.
>> Sorry Dave.
>>
>> I've got a quick kind survey question on acro. I
>> bought the V kit for xc reasons, but are any of
>> you out there doing cuban eights? Is the airplane
>> any good as an acro platform? I know it can take
>> the G loading...but what about roll rate with
>> rudder deflection not centerline? Rudder and
>> aileron size and effectiveness? I didn't
>> understand a thread in the archives about dishing
>> out of an aileron roll...did they mean like
>> barrel roll? If you raise the nose just a little
>> and bang the stick to the left won't it just roll
>> around a point w/ very little if any heading
>> change, as opposed to barrel roll where the
>> flight path simulates a corkscrew as opposed to a
>> spinning top?
>>
>> Are there and VNE problems w/ say doing a simple
>> split S and no speed brake? The only acro I have
>> done is in jets, so I am a little lost on this
>> stuff. Has anyone developed any target
>> speeds/power settings for continuous cuban
>> eights? Anybody doing in trail formation stuff
>> that I could talk to off line?
>>
>> Thanks for helping with this. When I become more
>> informed myself, I hope to somehow return the
>> favor down line.
>>
>> Terry
>>
>> Now back to your regularly scheduled program....
>>
>> -----Original Message-----
>> *From:* reflector-bounces at tvbf.org
>> [mailto:reflector-bounces at tvbf.org] *On
>> Behalf Of *davedent at comcast.net
>> *Sent:* Saturday, February 19, 2005 7:18 PM
>> *To:* rwhenderson at msn.com; Velocity Aircraft
>> Owners and Builders list
>> *Subject:* Re: REFLECTOR: WANTED: West Coast
>> CFI (SF Bay Area)
>>
>> Check with Steve Murphy. He gave me my
>> company check ride. Also has checked out
>> many others. He will charge you a small fee
>> for the check ride and light fees for the
>> training in your plane. Plus his cost for
>> fuel to come to your airport. He live up in
>> the Reno area.
>> He had no problem with me seeing I had 1500
>> hrs in canards before flying my Velocity. I
>> now have 60 hrs on it since last March.
>> I'm not a CFI but if you need time in a
>> Velocity before you fly yours come by and we
>> can make it happen.
>> Dave N32XL
>> LVK
>> -------------- Original message --------------
>>
>> > Anyone know any good instructors on the
>> West coast? I'm looking for a CFI
>> > with Velocity experience in the San
>> Francisco Area for an insurance check
>> > ride & sign-off.
>> >
>> > Must be a CFI w/ at least 50hrs in a
>> Velocity (SUV preferred, but not
>> > required). Any referrals would be greatly
>> appreciated!
>> >
>> >
>> > Thanks,
>> >
>> > - Rob Henderson
>> > rwhenderson at msn.com
>> >
>> >
>> >
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