---------------------------------------------------------- Lightning-List Digest Archive --- Total Messages Posted Sun 08/08/10: 5 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 03:14 PM - Re: Lightning Elevator flutter (robert keen) 2. 04:48 PM - hackman mixture unit (Tex Mantell) 3. 07:05 PM - Re: hackman mixture unit (Bill Strahan) 4. 07:14 PM - Re: Lightning Elevator flutter (Bill Strahan) 5. 08:12 PM - Re: Lightning Elevator flutter (N1BZRich@AOL.COM) ________________________________ Message 1 _____________________________________ Time: 03:14:51 PM PST US From: "robert keen" Subject: RE: Lightning-List: Lightning Elevator flutter Nick, I have experienced elevator flutter twice at around 140 knots indicated. I was told by the Australian agent Dennis, that it would be a loose tape under the wing. I have not yet retaped the wing joint yet, but I would like the Mass Balance figures so I can check the elevator myself. Can you send me the info please? I will keep you posted on what I find. Also do you have the mass balance figures for the ailerons? Should the Lightning have bungie cords on the elevator pushrod to hold some weight? Thanks Smokey. From: owner-lightning-list-server@matronics.com [mailto:owner-lightning-list-server@matronics.com] On Behalf Of flylightning Sent: Thursday, 5 August 2010 11:06 PM Subject: RE: Lightning-List: Lightning Elevator flutter No. Did you experience this or just simply asking? The prototype was mass balanced at first but when looking at light sport and saving weight we removed the balances and retested. There was no evidence of flutter. We dive test every LSA Lightning to Vne, 180knts IAS ( 208mph) with proper attempts to induce flutter with no issues. It is required by the ASTM on every aircraft. Nick Otterback Arion Aircraft, LLC _____ From: owner-lightning-list-server@matronics.com [mailto:owner-lightning-list-server@matronics.com] On Behalf Of robert keen Sent: Thursday, August 05, 2010 3:06 AM Subject: Lightning-List: Lightning Elevator flutter Has anyone had a problem with elevator flutter? Can anyone tell me the mass balance limits of the lightning control surfaces? Thanks Smokey http://www.matronics.com/Navigator?Lightning-List http://forums.matronics.com http://www.matronics.com/contribution Checked by AVG - www.avg.com 18:25:00 ________________________________ Message 2 _____________________________________ Time: 04:48:11 PM PST US From: "Tex Mantell" Subject: Lightning-List: hackman mixture unit I have recently installed the Hackman Mixture control in my Lightning and it seems to work as advertized. At cruse at altitude its save about a half gallon an hour as indicated by the flow meter. I would like to know who else is using this device and what experiences, precautions, etc. that others have found. Thanks TEX ________________________________ Message 3 _____________________________________ Time: 07:05:59 PM PST US Subject: Lightning-List: Re: hackman mixture unit From: "Bill Strahan" I love it as well, but it does work differently from a conventional mixture control on a lycoming/continental. By that, I mean it is dependent on power setting. In a lycoming, if you are properly leaned at altitude you can make power changes and the engine will continue to run. Not so the Jabiru/Hacman combo. If you increase the power you will immediately be running too rich. If you decrease it, too lean. Decrease it too much and the engine stops. There were a few times that I leaned at a low altitude when I first had the unit, then forgot about it in the pattern because I was not used to having the mixture control as part of my landing checklist. When I reduced the power on downwind the engine quit! I'm embarassed to say I performed this self-induced increase in blood pressure a second time before I finally integrated the use of the control. So don't forget it's there, and if you pull back the power at altitude for any reason, don't be shocked if the engine wants to quit. I've done that a time or two as well, just pulled back the power quickly when encountering some heavy turbulence and it caught me off guard when the engine started stumbling. I'm going to take my younger daughter to L.A. tomorrow for some father/daughter time. I'll take the O2 and will come back at 15-17k weather permitting. Who knows, maybe tailwilnds and Hacman will let me fly nonstop back to Dallas. :) Read this topic online here: http://forums.matronics.com/viewtopic.php?p=307991#307991 ________________________________ Message 4 _____________________________________ Time: 07:14:18 PM PST US Subject: Lightning-List: Re: Lightning Elevator flutter From: "Bill Strahan" Perhaps I'm poorly educated on the subject, but I thought in most cases of control flutter the time between onset and airframe failure was less than it takes to say "hey what is that?" I'm sure it's possible to have an episode of flutter, and even more likely to have some buzz that would precede flutter, and live to tell about it, but it seems very unlikely. When I was testing 7RW I eventually worked my way to 200knots true with autopilot off and hands off the controls so the inertia of the system was as little as it could be. I did stick slaps at 190knots true and saw the system return to equilibrium at the same rate it had at every other speed up until that point. That was enough to make me feel okay with the speeds at which I would be operating. I hope that the results of this inquiry are shared on the list. I'm not concerned for 7RW but would like to find out what is learned in this situation. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=307994#307994 ________________________________ Message 5 _____________________________________ Time: 08:12:27 PM PST US From: N1BZRich@AOL.COM Subject: Re: Lightning-List: Lightning Elevator flutter Hi Smokey, I don't want to totally disagree with your flutter assessment, but I kind of doubt that what you felt was true elevator flutter. Here is why - Many other Lightning builders, during the 40 hour phase one test period, have flown their Lightnings to Vne without any hint of flutter. And in the case of the prototype, Nick and I have flown it to well beyond the published Vne in several different stabilizer/elevator configurations. First, with the full aerodynamic and dynamic counter balance, they with a lesser modified configuration (not as large an aerodynamic counterbalance), and finally with no aerodynamic counter balance at all. In each case, absolutely no flutter, or to be more specific not even any indication of flutter. So if your airplane is having a problem, something may be different about your airplane. But lets not totally rule it out yet until we know more from you. So can you give us some more information to go on? For example, you said it happened twice at about 140 knots indicated. Was that the first two times you had your Lighting to 140 knots? Or has it been beyond that before with no problems on other occasions? When it happened, what did you feel (or see) to make you think elevator flutter? Was the stick moving? If so, could you freeze the stick with hand pressure? What did you do to case what ever was happening to stop happening? Did it stop immediately whey you did that? How much flying time on your airplane? Have you checked the elevator control system to see if there is excess slop in the system? Is anything looser now than before? I have seen at least one case where some rod end bearings developed some slop and the extra slop did cause some minor aileron buzz but no real buffet. Do you have the modification with the elevator trim tab? If so has that tab been there all along? And if so, how is the hinge for the tab? Has it loosened up? Sorry for all the questions, but these kind of things will help diagnose the problem and come up with a fix. As Dennis hinted at, with no tape between the wing and the fuselage karman, you will probably have a higher stall speed and some strange buffet feelings, but it is not flutter. So you might want to check that area. Other than the above, I can offer no other suggestions until we hear more from you. Nick will certainly jump in here when he see this on Monday morning. Rest assured that the Lightning is one of the more thoroughly tested designs out there. It is way stronger and thus safer than it has to be, but that is the basic design philosophy that Arion goes by - better than the others. I look forward to hearing from you. Blue Skies, Buz In a message dated 8/8/2010 6:15:48 P.M. Eastern Daylight Time, smokeysmail@bigpond.com writes: Nick, I have experienced elevator flutter twice at around 140 knots indicated. I was told by the Australian agent Dennis, that it would be a loose tape under the wing. I have not yet retaped the wing joint yet, but I would like the Mass Balance figures so I can check the elevator myself. Can you send me the info please? I will keep you posted on what I find. Also do you have the mass balance figures for the ailerons? Should the Lightning have bungie cords on the elevator pushrod to hold some weight? Thanks Smokey. From: owner-lightning-list-server@matronics.com [mailto:owner-lightning-list-server@matronics.com] On Behalf Of flylightning Sent: Thursday, 5 August 2010 11:06 PM Subject: RE: Lightning-List: Lightning Elevator flutter No. Did you experience this or just simply asking? The prototype was mass balanced at first but when looking at light sport and saving weight we removed the balances and retested. There was no evidence of flutter. We dive test every LSA Lightning to Vne, 180knts IAS ( 208mph) with proper attempts to induce flutter with no issues. It is required by the ASTM on every aircraft. Nick Otterback Arion Aircraft, LLC ____________________________________ From: owner-lightning-list-server@matronics.com [mailto:owner-lightning-list-server@matronics.com] On Behalf Of robert keen Sent: Thursday, August 05, 2010 3:06 AM Subject: Lightning-List: Lightning Elevator flutter Has anyone had a problem with elevator flutter? Can anyone tell me the mass balance limits of the lightning control surfaces? Thanks Smokey http://www.matronics.com/Navigator?Lightning-List http://forums.matronics.com http://www.matronics.com/contribution http://www.matronics.com/Navigator?Lightning-List http://forums.matronics.com http://www.matronics.com/contribution Internal Checked by AVG - www.avg.com 18:25:00 (http://www.matronics.com/Navigator?Lightning-List) (http://www.matronics.com/contribution) ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message lightning-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Lightning-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/lightning-list Browse Digests http://www.matronics.com/digest/lightning-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.