klares
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Posts posted by klares
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When I was building mine, I was worried about the canopy brace (which you don't have to, it seems- you have gull wings), and moved my rudder pedals forward, which dropped my knees, and made more room for the stick. I'm 6', and 195, and I fit ok, but the passenger side seems to have less room.. and you can darn well forget the back. I fit the floor in the back, and then took it back out- easier to check for water, and after squeezing myself into the back, once, knew that I would NEVER have anyone back there, so no need for a floor.
Water is an issue- the step is pretty shallow, and any water in the cabin area can QUICKLY migrate aft into the tail at a not-so-steep climbout, and do all sorts of nasty things to your weight and balance. I have an automatic/manual bilge pump, and an indicator light that tells me when it's operative. On approach to water landings- it's on automatic, and stays there until takeoff, when it goes to manual (after insuring that it's not currently running- did I mention that I have the floor out in back so I can check for water?). I do a shallow climb with the pump ON, and then switch to auto, checking for water ( light still on) before I try and increase my climb angle (light off).
Why so picky?
I knew Jim, and had land-taxied in his catalina with him. His had modified landing gear, which didn't leave him much clearance between the step and the ground- any little bump, and he'd drag, especially with both of us in the plane- something to check for. He was also fighting water incursions- and from all accounts, tried to yank it off the water, and the water jumped the step.. Recommendation? Do a few high-speed taxis on the water, stop, and check for leaks (you do NOT need that rear floor...). If it seems dry, still be cautious. Before heading out to a lake for landing, I actually mowed a path and rigged a ramp into a stock tanks (acre-sized pond), and drove around in that a bit, and found a significant leak around one axle. I made a packing bearing for the inside axles, and filled the outside gap (?) with 3m 5200 sealant. I still get a bit of a weep, but I can live with it.. especially with that light...
The only concern I had when looking at the pics of the plane on ebay were about the "f1" mods to the engine shroud. While having that one big radiator out on one side of the plane is draggy, if you look at the standard 582 installation, the engine shroud is pretty aerodynamic, which gives you a smoother flow into the propeller, allowing it more of a bite(power) and less noise. If you find that you don't seem to have much power, and have a really coarse setting on your prop, that's where I'd look first. Look at the open area behind the firewall on your plane, and mine. I've even streamlined the push-rods for the flaperons since, just to clean up the air into the prop, and smoothed out some of the extraneous stuff on the forward cowling designed for other engines.
Have fun! But.. don't expect to be in a hurry to get there- it's a pretty draggy airplane.
Jack- Austin, TX
Is this your plane? Is that a hirth engine?
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Are any of you guys coming down to the Valdez fly-in? I'd love to have a chance to look at other Avid's or Kitfox. Can a regular member add to the calendar on here I see just birthdays on there no events? Let me know if I posted this in the wrong spot
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Hey any updates to your plane?
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What's more common, primers or choke (enrichment circuit)? I've always had better starting performance from primers and lower maintenence from chokes (primer orings tend to leak by with infrequent use). My mkiv is premix, haven't had to clean plugs to start it yet, all 5 times
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This is an AWESOME build, can't believe I just now saw it. I'm down in Valdez, would love you check out your plane sometime. I'm curious about the heads, looks like they are clocked a bit off? The head bolts look symmetrical. Wondering if they weren't meant to have the cooling fins flat so the air can easily go across them. Only other concern with it other than cooling would be if the combustion chamber is designed with the porting in mind. Anyway great job, I've also been looking at Hirth engines and have been hoping someone up here would get one I could check out.
Ken
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Thanks for the update, at that alt I'm sure the extra hp is a big help! I wonder if cheek radiators with deeper cores are available, what kind of water temps do you normally see?
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Any updates on your bird?
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I also changed to premixing, partly to insure I always had enough oil and partly weight and C.G.as the engine and exhaust system is heavier. Mike Hair is my neighbor and helped me build the 670. I then helped him with the build of a 720 (670 bored to accept Polaris pistons). I ran my 582 for 700 hours trouble free but was getting concerned about the high time. I also had a leaking oil injection check valve for the latter part of that and thought this is a way to eliminate this problem.
Dave
Hi Dave, does your friend Mike have a thread on here? Any information on how the 720 is performing? It will be interesting to see the differences between his and yours.
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I built the wings to the book specs before reading that I should have done them less... oh well lessons learned i guess. spent yesterday going over everything, cleaned the plugs, new thermostat, added a tiny tach to confirm the MGL. took it up early this morning to check it. still no good. climb out was 200-300 fpm at 60 mph, 6300 RPMs confirmed exact by the second tach. EGS's 1050-1060 water is a bit of concern though best was 111* I was hoping the new thermostat would get it up higher but it didn't. not sure where to go with that. I'm still wondering if i'm spinning this prop to fast. still hoping to see what gear ratios/prop combinations some of you are using. I've been fighting this for a while and I'm running out of ideas.
Just curious what is the air temp and what elevation are you at? I kinda wonder about the water temp, I don't have any 582 experience but it seems most people run higher than that by a bit. That would indicate to me that you either have a really good cooling system or your not working your motor very hard. Another direction would be to compare speed with climb or even glide ratio (in similar conditions) with other avids regardless of rpm, if your way off then I would think plane setup. If your not too far off there then I would think your not getting full potential out of the engine, which your cool water temps would back up unless your overcooled in some manner. I would try pitching it to get 6500 rpm on climbout and see how much that changes things.. The other thing I would do is a conditional checkup on the engine, compression test, I'm not sure if the timing is adjustable if it is i would check it.. Seems like your down on HP or prop effeciency or both.. If it isn't a drag issue.. But like I said I don't have any experience with 582's just general two stroke principles.
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Thanks for sharing MarkD, how do you like the Hirth? I always thought one of there 3 cylinder liquids or that flat four they have would be a hotrod in an Avid/Fox.
Daryl from warp drive called and I'm a bit overloaded with info, but i think for what i want to do with a 582 the setup would be 3.47 gear ratio with a 72" three blade IFA. Max Stol and still be able to dial more pitch in for cruise.
However i'v never heard of someone using a 3.47 ratio on a kitfox/avid, although a few people who have ran both 3.00 and 2.62 seem to like the 3.00 better.. maybe 3.47 is better yet.
Anyone know how big a prop you can hang on a C box? or Avid for that matter?
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I think the 787 Sea doo motor would be sweet and if you look at the pto end it has some meat on the cases and holes drilled and tapped, could make and adapter plate. I feel these motors would be a better fit than the sled motors, there port timing and exhaust are built to run 6500-7000rpm not 8K. If you wanted to get some more ponies the yamaha gxr1200-1300 size triple two strokes are a reliable 135-150hp with lots of them running around with more than 500 hours on the top end.
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Not to split hairs here but,
the short speedwing or the aerobat wing will have almost the same amount of washout as the STOL or HH wing if they're extended and were built by the manual.
The speedwing and aerobat wing are built (per manual) with 9' spars and have 1.5" of washout. The STOL or HH wing calls for 2" of washout in 12' which is the same 1/2" of washout per 3'
I built the extended Aerobat wing for my Avid and I've been considering building a different set of wings with little or no washout using the kitfox 4-7 rib profile.
Travis
What prompted you to build the extended Aerobat wing, did they claim better stol at some point? How much better is the kitfox wing, anyway to quantify it?
I keep seeing that the highlander uses a wing like the Avid, anyone know how closely they are related?
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I read the different wings thread and I think i get it.
So the question is how did the builder go about it?
I got my info second hand that it had been built with aerobat wings but out to HH length, not really sure if it was with an extension or the way you describe.
Does anyone know a Gary Whittaker out of Tennesee by chance, he built the plane haven't had any luck getting ahold of him..
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Been reading a bunch lately can't seem to find info on anyone extending the aerobat wings to hh length. A plane I'm looking at has them. Can anyone explain how this would have been done what effect it may have on the plane?
Seen the post on the extended speed wings but I'm guessing there must be some differences.
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I got all excited when i saw the thread title 582 charging.... I couldn't help but think supercharger or turbo?
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Sorry i let this drop for a bit.
I believe there is a 3.47 and 4:1 ratio available for the C box, also I called and left a message for Daryl hopefully he gets back to me. I too think IFA is the way to go just wondering if a bigger prop turning slower might have some increased benefit.
I have considered going belt psru but i would like to have a clutch and im not sure if i want to tackle it.
Either way i wont be doing much experimenting until i have some seat time.
Looking to have an Avid Mk IV real soon.
Thanks to all who responded.
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Looking for a better understanding of gearing and prop size... If a guy wanted maximum stol performance would he choose the biggest prop he could clear, run the lowest gear ratio ie- 4:1 and pitch it accordingly? I'v read in several places that larger dia props turned slower provide better takeoff and climb performance. So where are avids/kitfox's limited, is it ground clearance for the prop? I think 3:1 is the lowest gearset i'v read of people using on these planes, does anyone have experience with the lower gear ratios?
Rotax 720
in Two Strokes
Posted
Are you referring to big bored 670's? In sleds people used to over bore them and use a seadoo 720 or 787 piston to make a 720 or 740. Or used a polaris 700 twin piston to make a it close to a 700. I think there's a guy in Florida and another in utah running a 740, I forget where I read it. Mike hair would know, he was making the exhaust. Actually, it might have been his plane. Have you got your 670's flying?