REFLECTOR: Sparrow strainer - I'm confused...
Brian Michalk
michalk at awpi.com
Tue Sep 18 14:58:52 CDT 2012
I think Hiroo Humeno added a servo that would actuate the sparrow
strainer in flight. I wonder how that worked out?
On 9/18/2012 2:48 PM, Carl Hoffman wrote:
> Turning a Sparrow Strainer into an adjustable trim tap seems to me to
> be a good idea.
>
>
> Sent from my iPad 2.
>
>
> On Sep 18, 2012, at 10:21 AM, Andrew Ellzey <ajlz72756 at yahoo.com
> <mailto:ajlz72756 at yahoo.com>> wrote:
>
>> Geoff,
>> Cutting the Sparrow Strainer off and reattaching it at a different
>> angle seems a bit harsh. I made my SS adjustable by potting a 10X32
>> nut plate inside each end of the airfoil. So the Airfoil is then held
>> in place on by two 10X32 screws. I am not flying yet, so I don't know
>> if my aircraft even needs an adjustable SS. But from all of the talk
>> of trim problems on the reflector, over the years, I thought that I
>> would be proactive and make my SS adjustable. I will install mine per
>> the manual, but if needed, I can change the angle of attack or even
>> invert my SS airfoil as some have suggested. I also think with a
>> little trial and error, I should be able to adjust the SS depending
>> on my aircraft CG calculations, due to passenger loading. This may be
>> wishful thinking on my part, due to the small size of the Sparrow
>> Strainer. I can send you a photo latter today if you think this
>> option will work for you.
>>
>> *From:* Geoff Gerhardt <geoff.gerhardt at gmail.com
>> <mailto:geoff.gerhardt at gmail.com>>
>> *To:* Velocity Aircraft Owners and Builders list
>> <reflector at tvbf.org <mailto:reflector at tvbf.org>>
>> *Sent:* Saturday, September 15, 2012 7:45 PM
>> *Subject:* Re: REFLECTOR: Sparrow strainer - I'm confused...
>>
>> Guys,
>>
>> Thanks for all the suggestions. What I think I may do is cut the
>> arms that join the SS to the elevator and then re-connect them
>> with the SS airfoil at a lower angle of attack to reduce the
>> speed-induced up-trim.
>>
>> Today, I had a great flight. I made some changes to my cooling
>> plenums that reduced temps in cylinder #3 (I'll describe these
>> changes in another email), so I was able to do a pretty
>> aggressive climb to 10,000'. I was going to do flutter testing,
>> but when I dove to gather speed, I found that too much stick
>> pressure was req'd to go above 180kts to properly assess flutter.
>> I could not trim it so that I could take my hand off to give the
>> stick a whack because I had to keep down pressure to stop from
>> climbing out of the dive. All control surfaces were fine to
>> 180kias, but I think I'll need to address the aerodynamic trim to
>> go higher. Or, is it okay to have stick pressure on when doing
>> flutter testing?
>>
>> Geoff
>>
>> On Sat, Sep 15, 2012 at 11:20 AM, Terrence Miles
>> <terrence_miles at hotmail.com <mailto:terrence_miles at hotmail.com>>
>> wrote:
>>
>> Geoff,
>> Over the past 10 years or so, the sparrow strainer debates
>> and opinions (which are always fascinating to me) and the
>> "running out of trim" issue come up on a regular basis.
>> Geoff, you are hardly the first in the test flight phase to
>> wrestle with this. I have the RGXL-5 with a LY IO540. I
>> weigh 150 pounds. Empty wgt she is 1928 lbs at 136.4 I
>> know other light weight pilots like me that fly with ballast
>> on the floor by the right seat. I don't because I have two
>> nose mounted Odyssey batteries. XC by myself with 70 gal of
>> fuel and the usual crap in the back seat area (125+ lbs) I am
>> at a CG of 130ish. With a 185 lb copilot it goes to 128.3 or
>> so if anybody out there is considering 2 nose batts be aware
>> of that limit. Because I am short I have the arm of my seat
>> is 79 inches. The copilot is at 83 inches.
>> I am not suggesting this for others, but with advice like you
>> are seeking right now, and more than several conversations
>> with Malcolm Collier and others, I decided to do this: The
>> factory trim spring didn't fit due to insufficient space
>> behind the panel without major changes. Also the stock
>> elevator trim motor throw was too short. I have a speed
>> brake trim motor running my elevator trim which is longer by
>> an inch or two. Yes, I have to watch for fractures in my
>> sawed off, reduced curve spring, but I don't run out of trim
>> no matter wgt, CG, or speed.
>> Terry
>> *From:*reflector-bounces at tvbf.org
>> <mailto:reflector-bounces at tvbf.org>
>> [mailto:reflector-bounces at tvbf.org
>> <mailto:reflector-bounces at tvbf.org>] *On Behalf Of *Richard
>> J. Gentil
>> *Sent:* Friday, September 14, 2012 10:31 PM
>> *To:* geoff.gerhardt at gmail.com
>> <mailto:geoff.gerhardt at gmail.com>; Velocity Aircraft Owners
>> and Builders list
>>
>> *Subject:* Re: REFLECTOR: Sparrow strainer - I'm confused...
>> Geoff,
>> To help solve the issue I just cut my sparrow strainer in half.
>> Richard
>>
>> Sent from my iPhone 4 Classic
>>
>> On Sep 14, 2012, at 10:01 AM, Geoff Gerhardt
>> <geoff.gerhardt at gmail.com <mailto:geoff.gerhardt at gmail.com>>
>> wrote:
>>
>> Guys,
>> As I'm flying more, I'm getting a better feel for the
>> plane and discovering little issues. I noticed yesterday
>> that when I really dangle (i.e. >160kts), I run out of
>> down trim. I guess I wasn't paying attention before, but
>> as I speed up, I need to keep adding down trim - I
>> thought that's what the sparrow strainer was for. As
>> speed increases, the canard is generating more lift, so
>> the sparrow strainer trims the nose down so that less
>> trimming is needed for speed changes. But then, I was
>> looking at the way the sparrow strainer is mounted and it
>> looks like it would do just the opposite. As speed
>> increases, the sparrow strainer will be pushed down,
>> adding trim up! I have my aerodynamic trim installed as
>> per factory instructions. I've heard of some who install
>> it upside down, which to me sounds like how it should be
>> installed. I have a feeling that if I remove it I'd have
>> to trim less with speed changes. Unfortunately, I used
>> some pretty aggressive silicone glue to put it on and I'm
>> afraid I'll make a mess of it taking it off.
>> Any thoughts on the effectiveness/correct installation of
>> aerodynamic trim?
>> Here's now I have mine installed:
>> http://thegerhardts.com/velocity/?p=491
>> Geoff
>>
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>
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