Hi Phill. I have been in China so nil progress for awhile. It will start again soon. I trust all is well with you. Say hello to your parents for me please.
Peter
Phill,I use the lightspeed QFR-XC purchased from ROB ROLLISON at ROLLISON AVIATION. ROB had me try several,but his first suggestion was right on ,I have since bought several items from him because of the way he does business ,the head set you purchase should be determined by the frequency of your power plant, and Rob is very knowledgeable in this area , and will tell you the least expensive, and give you the best price .happy and quiet flying BOB
Phil, here's the link to the Grove gear page with the specs. They use a different grade of aluminum, 7075 for a weight savings of 11 pounds over stock. I also used their lighter 51 series wheels, another 2+/- pounds saved. Ok, that's only 13 pounds lighter. I also added the gundrilled brake lines option.
Even though I deleted the landing gear, wheels, etc. from the Zenith kit, I believe the additional cost was right at $1,000, about $66 per pound saved. For me, it was money well spent.
Looks like you're making great progress. I hope to be flying in June.
Jake
Not sure what they are installing on the 650, from the pictures the gear does look to be narrower.
Zenith has instigated a Ground Vibration Test in Germany I believe, this data will be used as an input to the flutter analysis done by one or more engineers to identify if there is a real flutter problem and then of course hwo to deal with it. There is a utube video of the test setup linked tot eh man Zenith site.
I must apologize for not answering your questions in your previous post more directly.
In my opinion I think the present control system, given the right conditions, could be susceptible to aerodynamic flutter with possibly catastrophic results.
I, like others, do not believe cable tension alone is a satisfactory solution to the potential problem.
I have not noticed an indication of flutter onset flying in significant turbulence or over the operating speed range.
Using an aircraft cable tensiometer, my control cables were initially installed and maintained at the drawing specified tension of 30 ± 5 pounds. For the near future, I plan on maintaining a 30 to 35 lb tension.
I think the aileron bellcrank rib is sufficiently ridgid enough to sustain the reqd tension loads.
I checked out your web page and I like the 650 canopy structure idea.
This comment is a bit late I suspect, but I had an initial weight and balance issue. With no nose wheel, the CG was a bit too far aft at no fuel. Moving things around it finally came in. After painting my empty weight is 758 lbs.
During construction, I was initially a bit concerned that the ailerons were not balanced, but decided that because the design has been flying for some time without a problem, perhaps my concerns are unfounded. Well I guess I was wrong in view of passing events. I suspect because fairleads are used in the system rather than a pulley, keeping adequate tension on the cables introduces sufficient damping friction and the higher cable tension also increases the resonant frequency of the system sufficiently to reduce the flutter potential. Relying on cable tension alone does not seem to me to be a very reliable/suitable solution to the problem. As I recall, the aileron bellcrank rib was relative ridge and should not contribute to the problem. I must take another look at it. Be aware, when new cable is installed, initially there can be a small amount of apparent "stretch" as the cable strands come into conformity. After a short period of use and resetting the tension the cable tension should not change significantly. I have slightly over 150 hrs flight time on the airplane and had on one occasion slightly flown over Vne without ever experiencing any indication of the onset of flutter. A friend has flown his almost 500 hours, and in hot Phoenix summer turbulence, without indications of a problem.
Being faced with the flutter problem issue as many are, I was very pleased to see the photos of the push rod system. Unfortunately I was unable to find the photos of the Brazil XL with the aileron counter weights. Could you e-mail them to me or repost them. It would be very greatly appreciated.
Thanks,
Jim Timm
Classified listing for buying or selling your Zenith building or flying related stuff...
Custom Instrument Panels
for your Zenith:
Custom instrument panels are now available directly from Zenith Aircraft Company exclusively for Zenith builders and owners. Pre-cut panel, Dynon and Garmin avionics, and more.
Developed specifically for Zenith builders (by a builder) these videos on DVD are a great help in building your own kit plane by providing practical hands-on construction information. Visit HomebuiltHelp.com for the latest DVD titles.
Phill Barnes's Comments
Comment Wall (115 comments)
You need to be a member of Zenith Aircraft Builders and Flyers to add comments!
Join Zenith Aircraft Builders and Flyers
Peter
http://www.groveaircraft.com/landing_gear.html#zenair
Even though I deleted the landing gear, wheels, etc. from the Zenith kit, I believe the additional cost was right at $1,000, about $66 per pound saved. For me, it was money well spent.
Looks like you're making great progress. I hope to be flying in June.
Jake
Not sure what they are installing on the 650, from the pictures the gear does look to be narrower.
Here is the link to the vibration testing;
CH650E: Flutter - Ground Vibration Tests ... Zodiac CH650E
www.youtube.com/watch?v=0VMMVuVrweM
And yes all control surface on the RV are mass balanced.
Cheers
Eddie
Zenith has instigated a Ground Vibration Test in Germany I believe, this data will be used as an input to the flutter analysis done by one or more engineers to identify if there is a real flutter problem and then of course hwo to deal with it. There is a utube video of the test setup linked tot eh man Zenith site.
Cheers
Eddie
I must apologize for not answering your questions in your previous post more directly.
In my opinion I think the present control system, given the right conditions, could be susceptible to aerodynamic flutter with possibly catastrophic results.
I, like others, do not believe cable tension alone is a satisfactory solution to the potential problem.
I have not noticed an indication of flutter onset flying in significant turbulence or over the operating speed range.
Using an aircraft cable tensiometer, my control cables were initially installed and maintained at the drawing specified tension of 30 ± 5 pounds. For the near future, I plan on maintaining a 30 to 35 lb tension.
I think the aileron bellcrank rib is sufficiently ridgid enough to sustain the reqd tension loads.
I checked out your web page and I like the 650 canopy structure idea.
This comment is a bit late I suspect, but I had an initial weight and balance issue. With no nose wheel, the CG was a bit too far aft at no fuel. Moving things around it finally came in. After painting my empty weight is 758 lbs.
Regards,
Jim Timm
Ross jsut called and said somehting about not mass balancing?
I am proceeding with this as a next sttep based on information from Tony Bingellis.
What have you heard
Cheers
Eddie
During construction, I was initially a bit concerned that the ailerons were not balanced, but decided that because the design has been flying for some time without a problem, perhaps my concerns are unfounded. Well I guess I was wrong in view of passing events. I suspect because fairleads are used in the system rather than a pulley, keeping adequate tension on the cables introduces sufficient damping friction and the higher cable tension also increases the resonant frequency of the system sufficiently to reduce the flutter potential. Relying on cable tension alone does not seem to me to be a very reliable/suitable solution to the problem. As I recall, the aileron bellcrank rib was relative ridge and should not contribute to the problem. I must take another look at it. Be aware, when new cable is installed, initially there can be a small amount of apparent "stretch" as the cable strands come into conformity. After a short period of use and resetting the tension the cable tension should not change significantly. I have slightly over 150 hrs flight time on the airplane and had on one occasion slightly flown over Vne without ever experiencing any indication of the onset of flutter. A friend has flown his almost 500 hours, and in hot Phoenix summer turbulence, without indications of a problem.
Being faced with the flutter problem issue as many are, I was very pleased to see the photos of the push rod system. Unfortunately I was unable to find the photos of the Brazil XL with the aileron counter weights. Could you e-mail them to me or repost them. It would be very greatly appreciated.
Thanks,
Jim Timm
let me know how it goes
hows building going
they fly great i;m loving it but dont have enough time
regards Paul
cheers Kevin
Welcome to
Zenith Aircraft Builders and Flyers
Sign Up
or Sign In
Or sign in with:
New from Zenith:
Zenith Planes For Sale
Classified listing for buying or selling your Zenith building or flying related stuff...
Custom Instrument Panels
for your Zenith:
Custom instrument panels are now available directly from Zenith Aircraft Company exclusively for Zenith builders and owners. Pre-cut panel, Dynon and Garmin avionics, and more.
Zenith Homecoming Tee:
Zenair Floats
Flying On Your Own Wings:
A Complete Guide to Understanding Light Airplane Design, by Chris Heintz
Builder & Pilot Supplies:
Aircraft Insurance:
West Coast USA:
Pro Builder Assistance:
Transition training:
Lavion Aero
K&S Aviation Services
Aircraft Spruce & Specialty for all your building and pilot supplies!
How to videos from HomebuiltHELP.com
Developed specifically for Zenith builders (by a builder) these videos on DVD are a great help in building your own kit plane by providing practical hands-on construction information. Visit HomebuiltHelp.com for the latest DVD titles.