X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Fri, 26 Jul 2013 21:20:57 -0400 Message-ID: X-Original-Return-Path: Received: from nskntmtas02p.mx.bigpond.com ([61.9.168.140] verified) by logan.com (CommuniGate Pro SMTP 6.0.5) with ESMTP id 6392787 for lml@lancaironline.net; Fri, 26 Jul 2013 20:44:23 -0400 Received-SPF: none receiver=logan.com; client-ip=61.9.168.140; envelope-from=john@jjts.net.au Received: from nskntcmgw05p ([61.9.169.165]) by nskntmtas02p.mx.bigpond.com with ESMTP id <20130727004347.QDFA1968.nskntmtas02p.mx.bigpond.com@nskntcmgw05p> for ; Sat, 27 Jul 2013 00:43:47 +0000 Received: from [192.168.15.9] ([110.142.219.220]) by nskntcmgw05p with BigPond Outbound id 5Cji1m00J4luXCm01Cjjuo; Sat, 27 Jul 2013 00:43:47 +0000 X-Authority-Analysis: v=2.0 cv=G7ae4qY5 c=1 sm=1 a=6xIvA0WTx9AVOJiHBW+VeQ==:17 a=d56vjV6BgfAA:10 a=uoFbTxqA3N0A:10 a=mCSqThwqAAAA:8 a=I1SdC7XVI-cA:10 a=rTjvlri0AAAA:8 a=Ia-xEzejAAAA:8 a=CjxXgO3LAAAA:8 a=GDvJEaaRAAAA:8 a=gP-Iyt7oAAAA:8 a=jjqUt_clAAAA:8 a=lFYCgixrbzo6Lz8RgpoA:9 a=4VmKGKSqCdEA:10 a=5kvpSFHyPpYA:10 a=-ZBvsNeBbbMA:10 a=rnYgdqcAs4AA:10 a=Dr9Wx-Q63l4A:10 a=EzXvWhQp4_cA:10 a=rC2wZJ5BpNYA:10 a=nYNn1GbNWs8A:10 a=bR0bzt2bNa1EUox8z_gA:9 a=_W_S_7VecoQA:10 a=pwAuh9QEe42PoJgF:21 a=6xIvA0WTx9AVOJiHBW+VeQ==:117 User-Agent: Microsoft-MacOutlook/14.3.6.130613 X-Original-Date: Sat, 27 Jul 2013 08:43:40 +0800 Subject: Re: [LML] Re: Potential Problem-Engine Vibration From: John Smith X-Original-To: Lancair Mailing List X-Original-Message-ID: Thread-Topic: [LML] Re: Potential Problem-Engine Vibration In-Reply-To: Mime-version: 1.0 Content-type: multipart/alternative; boundary="B_3457759425_271194" > This message is in MIME format. Since your mail reader does not understand this format, some or all of this message may not be legible. --B_3457759425_271194 Content-type: text/plain; charset="Big5" Content-transfer-encoding: quoted-printable I did start to research the idea of locating accelerometers around the airframe =A1V seem to recall that I'd be spending several thousands on a "kit= " with all the boxes of tricks required to do this. I figured that there must be a solution around where there is an accelerometer that could be plugged into a simple signal amplifier and then to a laptop=A1K.. but gave up the search when someone told me about the iPhone accelerometer. If I could work out how to operate my iPhone remotely, I would be placing it in the wing ti= p and all sorts of other places around the airframe. Don't suppose there's an app around that allows remote control of one iPhone by another over their Bluetooth links?! However =A1V I think the iPhone is a very clever bit of kit, but without some testing, I wonder just how accurate its accelerometer is.. but at least it gives us a clue. So - does anyone have any ideas as to what / where to source a cost effective solution? Or may someone has the equipment already? BTW =A1V I don't have an stick vibration, and elevators / rudder are scallope= d per the Lancair supplied sections. Regards, John =20 John N G Smith Tel / fax: +61-8-9385-8891 Mobile: +61-409-372-975 Email: john@jjts.net.au From: Wolfgang Reply-To: Lancair Mailing List Date: Saturday, 27 July 2013 4:30 AM To: Subject: [LML] Re: Potential Problem-Engine Vibration > It sounds like accelerometers mounted in suspect locations with the engin= e > running at the RPM indicated by the spike shown by the Apple app. would l= ead > you to the culprit. > =20 > Wolfgang > =20 >> =20 >> ----- Original Message ----- >> =20 >> From: John Smith >> =20 >> To: lml@lancaironline.net >> =20 >> Sent: Friday, July 26, 2013 12:47 PM >> =20 >> Subject: Re: [LML] Re: Potential Problem-Engine Vibration >> =20 >>=20 >> =20 >> =20 >> =20 >> Kryilian, >> =20 >>=20 >> =20 >> I too have this vibration phenomenon in VH-XTZ ? I spent hours and hours= of >> flying time trying to isolate it, trying different power settings, diff= erent >> aircraft loading, different angles of attack, you name it ? I could not= find >> a pattern. Mostly its there, but occasionally nothing. Visually, it >> manifests itself with a very slight port wing tip / aileron quiver; >> physically, you can mainly feel it ever so slightly in the rudder pedals= . >> Having said all this, others fly in the aircraft and don't know what I'm= on >> about. But, I have now found that running at about 2540rpm is quite sm= ooth >> and all but gets rid of the vibration. Its noticeably worse at say 2400 = ? >> 2450rpm. >> =20 >>=20 >> =20 >> So ? endeavouring to quantify things, I employed the iPhone App you have >> mentioned. The attached pics are from way back in 2011; these should g= ive >> everyone an idea of what can be produced. Below my comments at the time = wrt >> to attached samples. >> =20 >>=20 >> =20 >> As one of our other forum contributors mentioned, vibration is very >> subjective without the use of measurement devices? so can I suggest that >> those whip have access to iPhones go flying and capture outputs in the = same >> manner and with same engine settings ? how about with iPhone resting on >> centre console and engine set at 2500rpm, 19" and leaned 28degC (50degF= ) >> rich of peak?. Or as anyone else might suggest otherwise. Then we can = all >> collect data that should be legitimately comparable, and perhaps identif= y if >> there are any substantial differences in the vibration characteristics. >> Anyways, just an idea?. >> =20 >> =20 >>=20 >> =20 >> Comments from tests in August 2011:- >> =20 >>=20 >> =20 >> Captured three outputs with 2400rpm and about 19? MAP. First sample wi= th >> iPhone on the centre console shows a spike at ~20Hz ? that is approx. >> equivalent to 1200rpm, which exactly half the engine engine rpm. For ot= her >> two samples, iPhone on the dust cover in the middle and then a bit to o= ne >> side; these show the same 20Hz spike, and also a spike around 38 - 40Hz= ? >> this would seem to be close to the engine rpm, but 38Hz is equivalent t= o >> 2280rpm, which does not make sense as there is no way the engine rpm va= ries >> by that much. So, I?m not sure what all this means. I?d love to get the >> iPhone onto the rudder pedals, but that?s kind of tricky! The iPhone do= esn?t >> measure above 50Hz, so I can detect prop beat or exhaust beat. >> =20 >>=20 >> =20 >>=20 >> =20 >> Regards, >>=20 >> John >>=20 >>=20 >> John N G Smith >> Tel / fax: +61-8-9385-8891 >> Mobile: +61-409-372-975 >> Email: john@jjts.net.au >>=20 >> =20 >>=20 >> =20 >> From: Kyrilian Dyer >> Reply-To: Lancair Mailing List >> Date: Friday, 26 July 2013 6:22 PM >> To: >> Subject: [LML] Re: Potential Problem-Engine Vibration >> =20 >>=20 >> =20 >>> =20 >>> =20 >>> =20 >>> If you'd like to measure the frequency and amplitude of relatively low >>> frequency vibration I'd recommend an iPhone app called 'Vibration' ($4.= 99 >>> from the App Store). It's certainly not high end but it may help in >>> characterizing some of the vibrations that you guys describe. The only >>> problem I see is that it only samples up to 100 Hz, which gives you >>> frequency data up to 44.9 Hz (~2690 rpm). This won't give you any data= at >>> propeller frequencies. But it may help tell if its a function of RPM = at >>> 1/rev, or if it's asynchronous with the engine (and doesn't correlate = with >>> engine speed, such as buffet or flutter). >>> =20 >>>=20 >>> =20 >>> A few screenshots (recording of an out of balance car tire at 70 mph) = are >>> shown below. Note that the app can output data to a .csv file, which ca= n be >>> reviewed/analyzed later. I do this sort of thing with proper >>> accelerometers, recorders and analyzers on helicopters in my day job, s= o I'd >>> like to help if I can. If anyone has luck with the iPhone app please = send >>> me the data files. Perhaps we could then compare between aircraft. >>> =20 >>>=20 >>> =20 >>> Regards, >>> =20 >>> - Kyrilian >>> =20 >>> L2K-236 >>> =20 >>>=20 >>> =20 >>> Time display: >>> =20 >>> =20 >>>=20 >>> =20 >>> DFT (note spike at around 16 Hz) >>> =20 >>> =20 >>>=20 >>> =20 >>> Setup (one of several sub screens) >>> =20 >>> =20 >>>=20 >>>=20 >>> Sent from my iPhone >>> =20 >>>=20 >>> On Jul 25, 2013, at 8:46 PM, "Dennis Johnson" >>> wrote: >>>=20 >>> =20 >>>> =20 >>>> =20 >>>> I have a smooth running Legacy RG IO-550 with a three blade Hartzell >>>> scimitar prop, HC-J3YF-1RF/F7391D-3/SM7. >>>> =20 >>>> =20 >>>> =20 >>>> According to Hartzell's website, this is the recommended three blade >>>> scimitar prop for the Legacy RG with IO-550 engine. It is a 72" diam= eter >>>> prop, not the 78" prop mentioned in Bob R's posting. I thought all t= he >>>> scimitar props on Legacys were the same as mine. >>>> =20 >>>> =20 >>>> =20 >>>> http://hartzellprop.com/pilots/kit-builders/legacy-2000-io-550-n-3-bla= de/ >>>> =20 >>>> =20 >>>> =20 >>>> I consider mine to be "smooth," but that is a terribly subjective con= cept. >>>> However, I can say for sure that I do not feel vibration in the stick= and >>>> don't see any aileron vibration or wing tip vibration. Another Legac= y >>>> builder and pilot commented on how smooth mine is, but maybe he was j= ust >>>> being polite.=20 >>>> =20 >>>> =20 >>>> =20 >>>> Unless there is a way to quantify "vibration" and "smoothness," I don= 't >>>> see how we can accurately communicate about this. One person's rough >>>> could be another person's smooth. Maybe if someone had a video of st= ick >>>> shake or aileron shake? A glass of water sitting on the glare shield= ? >>>> =20 >>>> =20 >>>> =20 >>>> Dennis >>>> =20 >>>> Legacy 625 hours >>>> =20 >>>> =20 >>>> =20 >>>> =20 >>>> =20 >>>> =20 >>>> =20 >>>> =20 >>>> =20 >>>> =20 >>>> =20 >>>> =20 >>>> =20 >>>> =20 >>>> =20 >>>> =20 >> =20 >>=20 >> =20 >>=20 >> =20 >>=20 >> =20 >>=20 >> =20 >>=20 >> =20 >>=20 >> =20 >>=20 >> =20 >>=20 >> =20 >>=20 >> =20 >>=20 >> =20 >>=20 >> =20 >>=20 >> =20 >>=20 >> =20 >>=20 >> =20 >>=20 --B_3457759425_271194 Content-type: text/html; charset="Big5" Content-transfer-encoding: quoted-printable
I did start to= research the idea of locating accelerometers around the airframe – se= em to recall that I'd be spending several thousands on a "kit" with all the = boxes of tricks required to do this. I figured that there must be a solution= around where there is an accelerometer that could be plugged into a simple = signal amplifier and then to a laptop….. but gave up the search when s= omeone told me about the iPhone accelerometer. If I could work out how to op= erate my iPhone remotely, I would be placing it in the wing tip and all sort= s of other places around the airframe. Don't suppose there's an app around t= hat allows remote control of one iPhone by another over their Bluetooth link= s?!

However – I think the iPho= ne is a very clever bit of kit, but without some testing, I wonder just how = accurate its accelerometer is.. but at least it gives us a clue.

So - does anyone have any ideas as to what / wh= ere to source a cost effective solution?  Or may someone has the equipm= ent already? 

BTW – I don'= t have an stick vibration, and elevators / rudder are scalloped per the Lanc= air supplied sections.

Regards,

John
John N G Smith
Tel / fax:    +61-8-9385-8891
Mobile:      +61-409-372-975
Email:         john@jjts.net.au
=

= From: Wolfgang <Wolfgang@MiCo= m.net>
Reply-To: Lancair Ma= iling List <lml@lancaironline.net<= /a>>
Date: Saturday, 27 July 20= 13 4:30 AM
To: <lml@lancaironline.net>
Subject: [LML] Re: Potential Problem-Engine Vibration

It sounds like accelerometers mou= nted in suspect locations with the engine running at the RPM indicated by the spike shown b= y the Apple app. would lead you to the culprit.
 
Wolfgang
 
----- Original Message -----
= From: John Smith=
Sent: Friday, July 26, 2013 12:47 PM
Subject: Re: [LML] Re: Potential Problem-Engine Vibration

Kryilian,

I too have this vibration phenomenon in VH-XTZ ? I spent hours and h= ours of flying time trying to isolate it, trying different power settings, different aircraft loading, different angles of attack, you name it ? I c= ould not find a pattern. Mostly its there, but occasionally nothing. Visually,= it manifests itself with a very slight port wing tip / aileron quiver; physically, you can mainly feel it ever so slightly in the rudder pedals.= Having said all this, others fly in the aircraft and don't know what I'm = on about.  But, I have now found that running at about 2540rpm is quite= smooth and all but gets rid of the vibration. Its noticeably worse at say= 2400 ? 2450rpm.

So ? endeavouring to quantify things, I employed the iPhone App you = have mentioned.  The attached pics are from way back in 2011; these shoul= d give everyone an idea of what can be produced. Below my comments at the t= ime wrt to attached samples.

As one of our other forum contributors mentioned, vibration is very = subjective without the use of measurement devices? so can I suggest that = those whip have access to iPhones go flying and capture outputs in the same man= ner and with same engine settings ? how about with iPhone resting on centre console and engine set at 2500rpm, 19" and leaned 28degC (50degF) rich of= peak?. Or as anyone else might suggest otherwise.  Then we can all collect data that should be legitimately comparable, and perhaps identify= if there are any substantial differences in the vibration characteristics. Anyways, just an idea?.

Comments from tests in = August 2011:-

Captured three outputs with 2400rpm and about 19? MAP.  First sample with iPh= one on the centre console shows a spike at ~20Hz ? that is approx. equivalent= to 1200rpm, which exactly half the engine engine rpm. For other two samples,= iPhone on the dust cover in the middle and then a bit to one side; these = show the same 20Hz spike, and also a spike around 38 - 40Hz ? this would seem = to be close to the engine rpm, but 38Hz is equivalent to 2280rpm, which does no= t make sense as there is no way the engine rpm varies by that much. So, I?m= not sure what all this means. I?d love to get the iPhone onto the rudder peda= ls, but that?s kind of tricky! The iPhone doesn?t measure above 50Hz, so I ca= n detect prop beat or exhaust beat.


Regards,

John

=
John N G Smith
Tel / fax:    +61-8-9385-8891
Mobile:      +61-409-372-975
Email:         john@jjts.net.au


From: Kyrilian Dyer <ky= rilian_av@yahoo.com>
Reply-To: Lancair Mailing List <lml@lanc= aironline.net>
Date: Friday= , 26 July 2013 6:22 PM
To: <lml@lancaironline.net>
Subject: [LML] Re: Potential Problem-Engine = Vibration

If you'd like to measure the frequency and amplitude of relatively= low frequency vibration I'd recommend an iPhone app called 'Vibration' ($4.= 99 from the App Store).  It's certainly not high end but it may help = in characterizing some of the vibrations that you guys describe. The only = problem I see is that it only samples up to 100 Hz, which gives you frequency data up to 44.9 Hz (~2690 rpm).  This won't give you any= data at propeller frequencies.  But it may help tell if its a function = of RPM at 1/rev, or if it's asynchronous with the engine (and doesn't corr= elate with engine speed, such as buffet or flutter).

A few screenshots (recording of an out of balance car tire at 70 m= ph) are shown below. Note that the app can output data to a .csv file, whic= h can be reviewed/analyzed later.  I do this sort of thing with proper accelerometers, recorders and analyzers on helicopters in my day job, s= o I'd like to help if I can.  If anyone has luck with the iPhone app ple= ase send me the data files.  Perhaps we could then compare between aircraft.

 Regards,
- Kyrilian
  L2K-236

Time display:
3D"image.png"

DFT (note spike at around 16 Hz)
3D"image.png"

Setup (one of several sub screens)
3D"image.png"


Sent from my iPhone

On Jul 25, 2013, at 8:46 PM, "Dennis Johnson" <pinetownd@volcano.net> wrote:

I have a smooth running Legacy RG IO-550 with a three blade Hart= zell scimitar prop, HC-J3YF-1RF/F7391D-3/SM7. 
 
According to Hartzell's website, this is the recommended three b= lade scimitar prop for the Legacy RG with IO-550 engine.  It is a 72"= diameter prop, not the 78" prop mentioned in Bob R's posting.  I= thought all the scimitar props on Legacys were the same as mine.
 
 
I consider mine to be "smooth," but that is a terribly subjectiv= e concept.  However, I can say for sure that I do not feel vibrati= on in the stick and don't see any aileron vibration or wing tip vibration.  Another Legacy builder and pilot commented on h= ow smooth mine is, but maybe he was just being polite.   
 
Unless there is a way to quantify "vibration" and "smoothness," = I don't see how we can accurately communicate about this.  One per= son's rough could be another person's smooth.  Maybe if someone h= ad a video of stick shake or aileron shake?  A glass of water sitting= on the glare shield? 
 
Dennis
Legacy 625 hours 
 
 
 
 
 
 
 

<= /center>

<= /center>

<= /center>
 --B_3457759425_271194--