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SuberAvid added a post in a topic KITFOX RADIAL 28 Apr 2012

Ed,

I know exactly what you are going through since I was at the same place trying to figure out what to do with my Avid MKIV to put a Soob on it. I am glad i decided to go with the Avid+ fusalage; not a "cheap" fix but at the time not too bad. The end result I am very happy with not just that it handles the Soob fine without any added ballast but the extra room in width, legroom and huge baggage area is amazing after flying my MKIV for so long. I don't have to worry about getting turbulent upset from the left and not being able to get enough left stick movement with my knee, hand, and stick as hard agains the door as possible but not enough room to move with the carharts on. A few of those had me uncomfortable in the past.

The mount I have on my Soob is as short as it could possibly be; the pully on the water pump only clears the FW by an inch and about 1/4 inch from the MM to FW bolt. It makes it difficult to work back there; I have to use a camming oil filter wrench on a ratchet extension to get to it and a pain to get the new one back on but it keeps the weight as far back as possible.

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SuberAvid added a post in a topic Wing questions 28 Apr 2012

Thanks for all the info everyone, it leaves me a lot of options. The KF ribs sound tempting but will have to see what the cost is. Would they require using the KF flaperon or could I use the Avid flaperon with them?

I am definately thinking of the horner style tips that are a little longer. I know Brett has them as well; not sure if they are the same as the KF ones. Will have to check prices on those as well.

Leni, how did you form the leading edge aluminum sheet on yours and what thickness did you use?

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SuberAvid added a post in a topic Kitfox IV 1050 to 1200 GW increase 28 Apr 2012

Hi Ed,

Is is possible for you to post the info on the spar inserts for the Avid Magnum?

Thanks,

Randy

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EDMO added a post in a topic Wing questions 28 Apr 2012

Doug,
My design book says that if you angle those Hoerner tips in at about six degrees from back to front, with the trailing edge being the longest, you will cut your drag. But it did not say how much.
I plan to install mine that way, so I wont have any comparison on cruise speeds for that mod.
One degree = about .017 per inch, so you can figure out the measurements.
Dont know anything about the engineering where they put the extra rivets in the Magnum strut attachments, but put them on mine, figuring that "more must be better".
Ed in MO

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EDMO added a post in a topic KITFOX RADIAL 28 Apr 2012

I agree with all that you wrote.
I could have bought an Airdale years ago, and could have done the stretch - however, because of personal things, which I wont explain, a shortage of airplane cash, stubborness, hard-headiness, determination, and curiosity, I decided to do things a different way, by extending the Leading edges and increasing tail feathers, like Steve Wittman's designs, and other planes in the past.
I just hope that my way turns out to be workable, and flyable, when I am finished. I don't know if it is a "fix-all", but will share my findings in case it helps someone else if they are in a similiar position.
ED in MO

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Av8r3400 added a post in a topic KITFOX RADIAL 28 Apr 2012

The newer Kitfoxes (5-7SS) are longer and designed to be able to use the small certified motors. The SS model can handle the 200+ pound motors okay. The motor mounts for the Rotax 912 in the new plane is quite long, allowing the oem intake plenum and a side mounted oil tank.

I find it funny that this plane hasn't existed in almost 2 years. (Takes that long for SP to publish anything any more...) This plane was dismantled to rebuild it to the Lycoming test bed, due in no small part to the poor performance and low reliability of the Rotec engine - from what I was told by one of the factory guys at the Kitfox booth last year. It generated considerable buzz from people who saw it (it was quite pretty) but apparently it was a bitch to fly. Very temperamental to start and went through loads of gas and oil. I was told on several occasions on the trip to and back from Oshkosh, it gave John (McBean) fits not only trying to start it but while flying in cruise.

The best way to deal with a heavy Subaru motor in an Avid is to do the stretch modification from Airdale on your fuselage...

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Av8r3400 added a post in a topic Happy birthday C5 28 Apr 2012

Happy BD, Joey, and Welcome Home...

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C5Engineer added a post in a topic Happy birthday C5 28 Apr 2012

Thanks!!

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EDMO added a post in a topic Traveling to Alaska 28 Apr 2012

Sounds like Wolf Lake strip has improved and enlarged a lot since I was there.
Cliff was one of the early tennants. Probably still has a spot there. He passed me on the A & P oral exam - only took 3 years at UAA to pound that bit of info into my thick head!
Ed in MO

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EDMO added a post in a topic C-box ratios 28 Apr 2012

Apprediate all the info. I have a dual conversion plan drawn by (Messinger?). Don't know if I will use it.
Ed in MO

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akflyer added a topic in Avidfoxflyers General Hangar 28 Apr 2012

Happy birthday C5

Happy B day Joey, hope its a great one!:bday:

3 replies
600 views

EDMO added a post in a topic Wing questions 28 Apr 2012

Good suggestion Doug, regarding the thin plywood. I wanted to add an aluminum sheet under my extended LE, but was concerned about dents, heat expansion, gluing to wood ribs, etc. I am only going to add the plywood from new LE back to spar, to save weight, and probably will add VGs under the wing after flight tests.
Happy Birthday to you and C5.
Ed in MO

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EDMO added a post in a topic KITFOX RADIAL 27 Apr 2012

AND, The 210 pound 233? Not much improvement or performance gain here over the 170 pound, much cheaper, C-85, C-90, O-200 IMO, unless you need the fuel injection to get over the mountains. NOTE: Our highest "mountain?" here is 1700 MSL, and most mountain passes are less than 4000, so I've heard.
Don't know how long the Stratus mount is, but mine only leaves enough room to slip the fanbelt between the engine and firewall.
Ed in MO

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akflyer added a post in a topic KITFOX RADIAL 27 Apr 2012

Not to be a smart ass... but.. moved the battery and added EVEN MORE LEAD. Engine mount is as short as absolutely possible also. She sounds awesome, and looks cool, but goes WAY beyond the realms of practical That being said, it would be a fun lil grocery getter, but not an every day driver for the back country. Kind of a who has the bigger johnson type thing...

With that being said. The kitfox was originally designed for the little radial engine that rotec promised they could make, hence the round cowling... But it never happened and was not practical.

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EDMO added a topic in Avidfoxflyers General Hangar 27 Apr 2012

KITFOX RADIAL

QUESTION: Just read article in EAA mag this month about Kitfox 7 Radial. How did they manage CG with a 235 pound engine when we are having to add ballast or LE extensions for our 200 pound Soobs? Anybody got an answer? IMO, a $75K experimental, like some other $100K LSAs has left us budget-builders out of the game.
Ed in MO

6 replies
1,490 views

EDMO added a post in a topic EA-82 Power 27 Apr 2012

Believe I have found some info on the EA-82. Photo on RAM Performance site, South Carolina, looks like it was a double-overhead cam engine, much wider and heavier than the EA-81. I had remembered that it was not as desirable as the 81, although RFI did convert some of them with redrives for gyros or rotorcraft. Also believe the flywheel housing was cast in one piece with the block, instead of a seperate casting as for the 81.
ED in MO

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Av8r3400 added a post in a topic Happy Birthday Doug 27 Apr 2012

Do you want the penthouse suite or a balcony room?

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dholly added a post in a topic Happy Birthday Doug 27 Apr 2012

Didn't you get the heads-up? I'm staying with you and Julie in the trailer this year. Please make our dinner reservations early, I don't wanna get shut out of the fried lobster again!

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dholly added a post in a topic Wing questions 27 Apr 2012

Way to go Randy! Personally I agree with the 'one for land, one for sea' philosophy so... no question, no hesitation... I vote !

If you search up 'MTOW modifications' in the Avid+ forum, it should have the stiffener info and lotsa other good stuff. Just ask if you have any question not answered and I'll see if I have more info in my R&D files.

I too wanted to add a bit of wingspan to my standard length Avid wings, but not too keen on all the work involved for another 18" per side. I just sourced a used set of Kitfox 4-7 Hoerner tips. They are about 14" wide and I liked that I could easily make them removable vs. the standard fixed tips. In my case though (I built with the long spar to HH spec but substituted speed for HH ribs), I am shooting for (hopefully) most of the best of both Avid wing worlds vs. max STOL capability. I built both Mk-V and Avid+ wings with 1-1/2" twist vs. 2" per the manual and, knowing what I know now, wish I used less. I would not hesitate to use 1-1/4" or even 1" washout. IIRC, both my KF3 and KF 4-1200 use only 1/2" twist.

With 582's on front, my KF3 got off the ground a lot faster than my Avid Mk-IV. Climbed better too but I'm sure it had as much to do with empty weight as airfoil or wing length. I do, however, think the new Riblett airfoil on the KiIfox 4-7 is superior overall to both the KF1-3 and Avid HH airfoils. Just as much (arguably, even more) lift, and with less under camber, so you don't hit the typical Avid HH aerodynamic 'wall' at 90-100mph or so. I believe a KF 4 will easily out cruise an Avid HH by 15-20mph, and with less rpm and gas obviously. As Charlie Sheen would say, "Winning!". I were in your shoes with an unstarted Avid kit, I would be tempted to retrofit the Kitfox mixer into the Mk-IV and use Kitfox 4-7 ribs and flaperons. I think that airfoil, even on the std Avid length spar (basically one bay less than KF) would be great and would likely give performance very close to a KF and equal to or better than an extended Avid wing with HH ribs and short flaperons. The f/r spar carry through tube bushings distance of 27-1/2" is the same on both planes and, since you are likely going to make new lift struts, no real added work there. Keep in mind too, when I fold the wings on my Avid vs. KF, the KF is quite a bit longer (ie., harder to fit into a garage) and the ass end quite a bit heavier (ie., harder to wrestle around), should that be an issue for you (or resale). Of course, the leading edge cuff will add width in the wings folder configuation, so if you intend to transport in an enclosed trailer this might be a consideration. I can not fit my Avid+ w/ cuff inside a [legal width] trailer, and there was only about 1/2" clearance on each side of my KF4 w/cuff when the prior owner delivered it in his $20k custom trailer with full width rear door. It wasn't enough, see my "First fabric repair" thread, lol.

In any event, the leading edge cuff extrusion was an integral part of Harry Riblett's new KF airfoil. That wing chord is longer and necessitated the portion forward of the leading edge spar which, up to then, was used as the wing leading edge for all KF and Avid airfoils. KF and Airdale are the only sources I've ever heard of. There are differing reports of exactly how much, if any, STOL or stall benefit is gained from adding the cuff to the Avid airfoils. Seems like the speed wing benefits more overall than the HH, and the HH benefits most from a reduction in stall speed rather than an increase in STOL capability. I'm not sure anyone can say they definitely are worth the building time or weight penalty. Personally I think I would just add VG's to a HH wing (and under HS) and leave the cuff off. I did not add the cuff to my Mk-IV HH wings, but did add it to my Avid+ long speed wings. I did it primarily to sharpen my speed wing LE (like most aerodynamic mods, maybe help increase cruise?) and cover up the butt-ugly lift strut bracket and rivets from showing under the fabric. Never liked that aesthetically. Regarding the aluminum sheeting to prevent oil canning, I am seriously considering using thin marine ply instead. Joanne Heckman did that on her Avid and not only does it look great, it will not permanently dent like aluminum if it gets dinged. She used one thin layer of PolyFiber polyester padding over the ply and also the wing tanks, for both chaff protection and to avoid having to Bondo, Super-Fil and sand the f/g wrapping around the tanks smooth. Huge time-saver, that job sucks!
Have fun!

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SuberAvid added a post in a topic Wing questions 27 Apr 2012

This is a great help, Thanks Leni. As far as the radiators; I really don't know what I have yet; it is bought sight unseen except by Jack. I don't think it has any FW forward though except possibly the cowling. Will know more when we go to get it after I get back from the lower 48 in a couple of weeks.

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SuberAvid added a post in a topic Traveling to Alaska 27 Apr 2012

Ed, it can blow at Wolf Lake so there are days when you could fly out of Willow or Birchwood but that are two windy for me a Wolf Lake. I always figure it I get caught comming back from somewhere and it is too windy I will just land at a friends' place in Willow or Wasilla and catcha a ride home until the winds die down. So far have not ever had to do that though. Wolf lake is pretty big nowdays; I think the main runway is over 4000 ft, paved and lighted with plenty of cleared approach and very wide with grass and paved taxiways on both sides and a cross wind gravel runway that is probably 3000 feet and very wide. I always land on the grass closest to my taxiway. Cliff Stockton sounds familiar but I cant picture him for sure.
The time I flew down to meet Dave Goode I was not sure I had found his place but I had to pee so bad I was going to land somewhere even if it had to be in someone's yard; it turned out to be his place but I jumped out and headed for the trees as soon as I stopped.

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SuberAvid added a post in a topic C-box ratios 27 Apr 2012

Hi Ed, I run premium gas in mine just to minimize the chance of getting alcohol . I think most of the premium in a lot of areas still does not have alcohol and I don't want that wrecking my tanks. According to Stratus you can run 87 octane but I have not tried it and I doubt it I could hear it pinging if it was, so better to be safe and run the higher octane.

I have dual coils and an MDS coil joiner in mine. According to RAM you should not run both ignitions continuously at the same time or it can overheat the coil joiner and cause it to fail. The second ignition is a backup in case one fails but you have to switch the ignitions manually. I guess you could wire up two coils to a single pickup in the distributor and use a dual pole switch to switch from one ignition to the other but I tried to do that with the single ignition I had on my 670 Rotax and it didn't work. There was too much loss in the signal running the switch between the pickup and the coil so it would not fire the coils. Not sure if the Subaru would have more power but I think it would still cause a weak spark. On my Subaru I placed my ignition switches on the power going to the pickups and it works fine. I wired one on the alternator side of the system and the other directly to the battery so it bypasses my master switch, that way if I have to shut down the master switch if something starts smoking, the engine can still run on the secondary ignition. I got the distributor rebuilt and with dual pickups, dual coils and the coil joiner as a package from RAM for around $700. I think it might be cheaper to get the secondary ignition from Stratus but it is not in the distributor but instead is a pickup mounted on the block at the flywheel and reads off a magnet they put in the flywheel. It is more independent of the distributor if something were to nuke inside the distributor but requires the flywheel modification plus is more a limp home system since it does not have an advance system as the distributor has. The cheapest would be to build your own; use the stock electronic ignition pickups and mount a second one on the plate in the distributor oposite the stock one. I have also read some people say the GM pickups are a lot better than the stock Subaru ones but they may require a more custom mounting system; there is not much room inside the distributor and the second pickup really packs it full. The coils I got from RAM are just solid coils like you find on a motorcycle or ATV; not oil filled, and the MSD coil joiner can be found at many performance auto parts stores or mail order from JEGS or someplace like that.

I don't know if the Holly carb with an accelerator pump will be good enough without a primer but it might be. The Bing 64's don't have an accelerator pump and mine was terrible to start using just the enrichers as I had it set up initially. I added the primer to just one of the carbs and it was like night and day; when the engine is cold (I preheat it when it is below 20 degrees) I just pull the choke (enrichers) and give it 5 squirts of primer and it fires off on the first revolution.

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SuberAvid added a post in a topic C-box ratios 27 Apr 2012

Sounds good Leni, I need to write down the dates you are going to be in town so we can get some fishing trips in whenever you are home. That run down to Silver Salmon Creek in your old stomping grounds was a blast and we plan to do it again. Quite the bear concentration there but now I am going to be suspicious if I see you cooking bacon.

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SuberAvid added a post in a topic Kenai Air Fair 27 Apr 2012

Leni, glad it is going to match up to your schedule. Jack and I are planning to come. I was also going to try to make it to the Valdeze fly in this year but am leaving this Sat for a week class in Vicksburg, MS and will stop by the home place in Oregon for a week on the way back so will be gone during Valdeze. Hopefully will get another turkey hunt in while in OR though.

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EDMO added a post in a topic C-box ratios 27 Apr 2012

The heads on mine were milled 040, and the seller said to use mid-range mogas. Guess I will find out if I can run 87.
Do you have dual coils too, and electronic switching? Do I really need dual pickups? How much do they cost?
Mine has single set of points. Will double-check letters about max deg BTDC. Also, will decide if I need a primer, or can use that fitting for a carb temperature gage, or plug it. Never needed a primer on my 318 Dodge - Same Holly 2 brl - accelerator pump worked fine, just pump it 3 times when cold.
Again, thanks for info
ED in MO

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