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Hangar Flying / Re: Varieze Question on POA
« on: December 03, 2011, 10:29:45 PM »
I'd be interested. send me an email at arnold@av-mech.com
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2
Hangar Flying / Re: Off to Corvair College
« on: November 25, 2011, 06:16:38 AM »
No I do not but I have been giving it some thought. It's a little smaller, narrower, lighter than the O-200. It will make an honest 100-125 hp depending on which version you build. It is a six cylinder, short stroke engine and is very smooth. I have flown a Pietenpol for about 200 hours with a Corvair so I have some experience with operating it. I am continuing to think about it.
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Hangar Flying / Re: Move the battery????????
« on: November 24, 2011, 06:13:30 PM »
considering that there is at least 220lbs of engine right behind the supposed battery location, the battery is not going to be the only thing relocating to the cockpit in a bad crash. So I don't think that worrying about the battery coming loose in a crash when located on the firewall is a major concern.
I have my battery located on the aft side of the firewall and it sits in a carbon tray with 4130 tubing acting as legs that bolt to the engine mount bolts. The tubing was slit on the end and I welded tabs on each end with a bent angle necessary to line it all up. The tray is bolted to the tab using countersunk AN screws (with shank) and metal lock nuts. My master and starter solenoid are also attached to this tray and the battery cables and starter cables are very short. I have a #12 wire running up front to a 10 amp circuit breaker switch that controls the avionics. It only takes a #20 wire running from the master and starter button to activate the solenoids in the back. Easy Peasy Lemon Squeezy.
I have my battery located on the aft side of the firewall and it sits in a carbon tray with 4130 tubing acting as legs that bolt to the engine mount bolts. The tubing was slit on the end and I welded tabs on each end with a bent angle necessary to line it all up. The tray is bolted to the tab using countersunk AN screws (with shank) and metal lock nuts. My master and starter solenoid are also attached to this tray and the battery cables and starter cables are very short. I have a #12 wire running up front to a 10 amp circuit breaker switch that controls the avionics. It only takes a #20 wire running from the master and starter button to activate the solenoids in the back. Easy Peasy Lemon Squeezy.
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Hangar Flying / Re: Drag reduction as a function of vibration
« on: November 24, 2011, 06:05:37 PM »
Bill,
Ok, someone finally ask's....
On the power stroke, as the piston is being pushed downward the connecting rod has angular displacement between the wrist pin and the crankshaft journal. This connecting rod offset makes the piston itself "lean" on one side of the cylinder wall. Remember that the piston is being forced down by combustion gas, Depending on the position of the crankshaft, you get a little torque at the beginning of the downward travel and as the connecting rod becomes further off center more torque is applied to the cylinder wall via the piston, it all happens in 90 deg of rotation as the 91 st degree starts to unload the leverage the connecting rod had on the piston. So since the torque is transmitted through the connecting rod to the piston which leans on the cylinder wall and that cylinder is bolted to the engine case which in turn is connected to the engine mount and then airframe. You will of course note that the crankshaft has no mechanical connection that can provide leverage from the crankshaft itself. the crankshaft rides entierly on a film of oil.
It's a little tough to visualize, I will try to post a pictoral representation with force diagram that will help.
Ok, time for another trivia question>> What type of wing construction makes the main wing spar act as a sinasoidal wave when loaded??
Ok, someone finally ask's....
On the power stroke, as the piston is being pushed downward the connecting rod has angular displacement between the wrist pin and the crankshaft journal. This connecting rod offset makes the piston itself "lean" on one side of the cylinder wall. Remember that the piston is being forced down by combustion gas, Depending on the position of the crankshaft, you get a little torque at the beginning of the downward travel and as the connecting rod becomes further off center more torque is applied to the cylinder wall via the piston, it all happens in 90 deg of rotation as the 91 st degree starts to unload the leverage the connecting rod had on the piston. So since the torque is transmitted through the connecting rod to the piston which leans on the cylinder wall and that cylinder is bolted to the engine case which in turn is connected to the engine mount and then airframe. You will of course note that the crankshaft has no mechanical connection that can provide leverage from the crankshaft itself. the crankshaft rides entierly on a film of oil.
It's a little tough to visualize, I will try to post a pictoral representation with force diagram that will help.
Ok, time for another trivia question>> What type of wing construction makes the main wing spar act as a sinasoidal wave when loaded??
5
Hangar Flying / Re: Sharing my flight!!!
« on: November 20, 2011, 03:00:49 PM »
Afif,
Totally cool, I have been wanting to buy one of those cameras and do the same thing. Glad to see you posting videos, we need more.
Totally cool, I have been wanting to buy one of those cameras and do the same thing. Glad to see you posting videos, we need more.
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Hangar Flying / Re: Drag reduction as a function of vibration
« on: November 20, 2011, 02:54:43 PM »
Dave,
I am in possesion of the CSA molds for the Varieze pants and they look like they will do just fine, as soon as I can get them made!
I am in possesion of the CSA molds for the Varieze pants and they look like they will do just fine, as soon as I can get them made!
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Hangar Flying / Re: Move the battery????????
« on: November 15, 2011, 06:49:25 PM »
I presume you are talking about the battery..........as the engine is supposed to be in the back! 
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Hangar Flying / Inflight photos
« on: November 14, 2011, 05:58:04 PM »
Just thought I'd drop a few photos of my flight to SC and back. Hope it encourages those of you still building to get out to the hangar or garage and get something done!!
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Hangar Flying / Re: Off to Corvair College
« on: November 14, 2011, 05:53:07 PM »
Had a headwind going and a headwind coming home but still managed to average 165 mph. Corvair College was a smashing success with about 12 engines successfully test run and about a dozen others in various stages of disassembly or re-assembly. 75 people came from places like PA, CA, MI, SC, NC, FL, LA, IL, WA, OR......those are the ones I know about but others states were represented as well. I have included a couple of photos for your viewing enjoyment.
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Hangar Flying / Re: Move the battery????????
« on: November 14, 2011, 12:06:54 PM »
It's kinda difficult to say at this moment. You need to have the whole airplane together, ready to fly, and then weigh it. From that you must then decided if what you have done will work or maybe you need to move something.
Now I know that's not really a useful answer at this point so.........you can compare what your weight to what the last pilot was counting his weight as (maybe he used 170 lbs or maybe he used his real weight)whatever it was it should be shown in the last CG calc. Look at what his CG was and compare his configuration of the aircraft to what you are doing. This should give you a general idea of what to expect with your W&B.
Now I know that's not really a useful answer at this point so.........you can compare what your weight to what the last pilot was counting his weight as (maybe he used 170 lbs or maybe he used his real weight)whatever it was it should be shown in the last CG calc. Look at what his CG was and compare his configuration of the aircraft to what you are doing. This should give you a general idea of what to expect with your W&B.
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Hangar Flying / Re: Off to Corvair College
« on: November 11, 2011, 11:56:32 AM »
Bruce,
The weight is dependent on how you configure the engine but as a general reference, if you airplane was set up for an O-200 then a corvair is a good replacement.
The weight is dependent on how you configure the engine but as a general reference, if you airplane was set up for an O-200 then a corvair is a good replacement.
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Hangar Flying / Re: Off to Corvair College
« on: November 11, 2011, 07:32:33 AM »
I have spent a lot of time around the corvair guys, the HMFIC is one of my best friends and I flew his Pietenpol Aircamper back and forth to OSH several times from Central Florida. I think the Corvair is a viable alternative for both a high powered Vari (130 HP) and an adequte powered Long. I am tickling with the idea of swapping my O-200 for one. I am dedicated to refining the aerodynamics of the airframe first but who know's what the future holds. A good corvair engine that produces at least 110HP can be built for something on the order of $5K so it holds potenetial from at least an economic standpoint.
Corvairs are not just for Pietenpols either, they are commonly found on Sonex's, Soneri's, Zenith 601/701, Midget Mustangs, Christavia's, Wag-a-Bond, Personal Cruiser, KR's, and several others. With several hundred flying hours behind one myself I can attest to the fact that properly built, they work really good in an airplane.
www.flycorvair.com
Corvairs are not just for Pietenpols either, they are commonly found on Sonex's, Soneri's, Zenith 601/701, Midget Mustangs, Christavia's, Wag-a-Bond, Personal Cruiser, KR's, and several others. With several hundred flying hours behind one myself I can attest to the fact that properly built, they work really good in an airplane.
www.flycorvair.com
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Hangar Flying / Off to Corvair College
« on: November 10, 2011, 08:28:31 PM »
Well after a grueling 4 day work week I am "Wheel up" in the morning for Barnwell South Carolina. Going to hang out until Sunday afternoon at Corvair College #21. You can get details about it at www.flycorvair.com. I worked late everynight this week to complete jobs so I could leave on Friday morning.
Weather is looking good, Vari is ready and I get three days of no wife, kids, or customers!!! Nothing but hardcore experimental aviation people who love to build engines. I'll come home with grease under my nails for sure!
Note to Stan Zinger, I will call you Friday afternoon.
I hope the rest of you get some flying or building time this weekend.
Weather is looking good, Vari is ready and I get three days of no wife, kids, or customers!!! Nothing but hardcore experimental aviation people who love to build engines. I'll come home with grease under my nails for sure!
Note to Stan Zinger, I will call you Friday afternoon.
I hope the rest of you get some flying or building time this weekend.
14
Hangar Flying / Re: Trailing Edge Fences.......WOW
« on: November 07, 2011, 11:58:29 AM »
Erik,
The LAA instructions mentioned above is exactly what I used and they work great.
The LAA instructions mentioned above is exactly what I used and they work great.
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Hangar Flying / Re: Drag reduction as a function of vibration
« on: November 04, 2011, 08:30:23 PM »
That guy started out at a .88" ips, that's super high and any balancing would have help that rotating mass. Bare in mind that your not just balancing the prop, your actually looking at the whole rotating mass. Prop, spinner, spinner backplate/bulkhead, flywheel, ring gear and crankshaft. No flywheel for continantal engines. They ended the balance at .06 which is not bad but I always work to get my balances under .030"ips, especially on Lycomings because they are easier to do than Continentals.
Now what we have found with pushers is that the dirty air coming into the prop really effects the balance job. I can do my Vari on the ground and get a reading in the .020" ips range, take it up flying and it will jump to .100" ips or so. This is not a common problem on tractor props. Why is it a problem for pushers? The dirty air causes more pronounced torque fluctuations in the crankshaft and this is felt as vibration. BTW I use the MicroVib II equipment which also performs advanced spectrum analysis functions, something the Dynavib does not do.
Trivia question: How is torque transmitted from the crankshaft to the engine case? I have the answer, do you?
Now what we have found with pushers is that the dirty air coming into the prop really effects the balance job. I can do my Vari on the ground and get a reading in the .020" ips range, take it up flying and it will jump to .100" ips or so. This is not a common problem on tractor props. Why is it a problem for pushers? The dirty air causes more pronounced torque fluctuations in the crankshaft and this is felt as vibration. BTW I use the MicroVib II equipment which also performs advanced spectrum analysis functions, something the Dynavib does not do.
Trivia question: How is torque transmitted from the crankshaft to the engine case? I have the answer, do you?