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I started this thread since I convinced myself that I need more take-off power than my 582 with a 2.62 gearbox and IFA IVO prop offer for my model 2.

IVO said a 3.47 gearbox with their 3 blade medium prop would make a big difference in take-off and climb.

I called a Rotax repair shop here in Oregon to see if they knew of any used 912's for sale not realizing they were also a Hirth dealer.

Are Hirth engines the latest and greatest that I have somehow not been exposed to?

I still want a 912 but it makes little financial sense to repower this Kitfox, versus finding a Model 4 with a 912S already installed.

Any advice?

Thanks Herman

I don't know.  I was told a seized rave valve caused the last engine out that it had.

Welcome to the "Middle-aged Club"

Being young is easy - You got to be tough to get old.  I promise not to remind you next year! 

EDMO

Tinkering on the 670s was the constant changing of plugs, carb adjusting, seized RAV valves, chasing the peaky unpredictable power, and on and on.

What caused the Raves to seize? Thanks, Bryce

I have the original AVID gel coat floats that are under 200 lbs.  I am wondering with the 582 what kind of performance I can expect.  Can you haul two people with floats?  What is the general take off distance with no head wind.  What can I expect the cruise speed to be.  The dry weight of my plane is 568.  It has the 29' 10" STOL wing. 

Thanks

it is coming back to life.  I have a good line on a machinist here on the forum who is willing to make the adapter plate to bolt the engine to the gear box.  I have the drawings made and the material cut to rough shape and ready for machining when I get home... I am certain it will take some growing pains and its a good thing I have several stock exhaust systems to play with and butcher to make the exhaust fit inside the cowling yet still retain the stock power, smoothness and lack of head ache / peakiness.  It will not be an over night install, but I am moving forwards with it!  If it pans out, my only issue (ok others issues) is that Suzuki is no longer making the engines for Arctic Cat.  I hope that when they start building them inhouse this year, they dont screw them up and turn a perfect engine into a POS... the good news is you can buy an older (06-09) engine and rebuild it pretty cheaply with new parts.

Re-reading your post about removing the FPR and noting a change in engine operation and fuel flow increase with the boost pump on would lead me to believe the boost pump puts out too high a pressure and is overwhelming the float valves. The FPR is necessary with this particular pump. A simpler solution would have been to use a lower pressue pump.

Other than a little added complexity and weight, what you've got should work fine. Just use the boost pump as Leni described you should have no problem.

The grove gear added some weight to my airplane but what really hurts it is the full instrument panel, no space is unused.

I'm also looking forward to seeing the 800 EFI 2-Stroke engine installation finished up.  I don't know if the project is still alive or not but when I read about on it I didn't see any disadvantages.  Lots of power (120-140) I think, lightweight, low fuel burn, fuel injection and good availability of parts.

SuberAvid

You responded with "Wide bungee gear fan" and Leni said the after market bush gears have had failures.

So who makes the gear you suggest?

 

Herman,

Leni did a good job answering your question.  I had the Airdale wide bungee gear on my Avid MKIV (with reinforced seat truss and Leni described) and the extra tall wide gear on my Avid+ that I built.  No problems and no failures, and with some pretty hard landings.  I think Airdale and another company (Highwing or something) makes the wide bungee gear.  I have never flown a plane with Grove gear and it sounds like many are impressed with it; but it is heavy and expensive, and I have seen a KF with it that has fusalage damage at the gear attachment.  No gear is fail proof but the wide bungee gear has worked very well for me.

the airplane has a NavMan 2100 installed with low fuel and fuel flow emergency warning lights along with an alarm that triggers when my wing tank is 1 gallon from empty so I can turn on the fuel pump for the header tanks.  It seems to be fairly accurate so far except on right taxi turns at idle, it shoots up to 8gph fuel burn, lol. 

all I have done is remove the regulator and let the fuel run from the fuel pump line.  Alot of fuel comes out of that 1/4" line in a very short amount of time, haha

What are you using to measure fuel flow? The common meters are notoriously unreliable and subject to installation errors especially in our ~5 gal/hour flow rates. Pressure pulses from a different type fuel pump could easily upset the measurements. These meters are great for measuring relative differences when playing with small throttle changes or mixture changes (if you have controllable mixture) but I wouldn't believe the absolute numbers without a good calibration and lots of flight experience with the particular installation.

Any fuel pressure between 3 and 6 psi delivered to the carb should keep the float bowl full and allow the float needle valve to regulate the fuel level. If the pressure gets too high, fuel can lift the float valve and cause rich running plus spilling fuel from the overflow. To low a pressure would allow the float bowl levels to drop and show signs of fuel starvation.

You want to be sure the fuel system can deliver more than sufficient fuel in any flight attitude. Have you done a gravity feed fuel test on this plane yet?

The cowl you have, are the cheek openings partially blocked off? (Sometimes done on a 912 install) How much "lip" do you have on the hot air exhaust on the bottom of the cowl?

(As a comparison, my plane is at 647 empty with a 80 hp 912 and heavy warp prop and grove gear.)

Mike I have been looking at your setup and it appears that you have developed a good solution. I have made some adjustments and have the brakes working ok for now. I will be in contact with you about your setup sometime in the future. Right now I would like to get the hours flown off before I start any more mods.

Thanks Mike,  I remember Steve Winder saying that you had to decide where you were going to start, either at the ends or in the middle, nothing else  worked very well.

Your comments  reminded me of that bit of advice.

Jack

It is a MK IV Avid, guess I will see how it does as the weather starts to warm up. Thanks and thanks Leni I made the adjustments to the wing but have not flown it yet to see if it is enough. Looks like Tuesday before I get another chance to check it out.

I noticed AeroVee does not offer PSRU options like Great Plains does.  Once you look at the weight of the Great Plains PSRU engines its not worth it.  180lbs +

My plane weight 628 with the Rotax 582 and C-Box.  If I add anymore weight I will never get off the ground with anything worth carrying.

Jack:

If I am remembering correctly, on my plane when I checked the brackets at the root and the tip were 50 deg. and all the ones in between were whereever they needed to be to get the flaps to work smoothly.

Please, please, please!  Do not waste your money on an VW motor in your plane!!!

Avids and Kitfoxes have been around 30 years.  VW conversions longer.  If there was a way to make them work in these plane there would be a bunch of them flying.  There isn't.  They are nearly unheard of.  I've known a few who have tried and one currently struggling with a AeroVee in a Just Escapade with nothing but heartache for his trouble.

VWs need a short high rpm prop and lots of cooling air through the cowl.  This scenario doesn't work in a slow, STOL airplane.  A little go-fast hotrod like a KR2 or Quickie or Sonex is a different story.

Tinkering on the 670s was the constant changing of plugs, carb adjusting, seized RAV valves, chasing the peaky unpredictable power, and on and on.

Oh - just a thought:  On my trip to NC this past spring, during a sustained climb all the way to 10,500 MSL, I did see an oil temp spike to 260 degrees.

Paul, refresh my memory, is your plane an Avid or Kitfox?  The Avids have a tighter cowl with less air going through, so a cooler is usually needed.

I am not running an oil cooler on my Kitfox IV, 912 80 hp.  I will occasionally see oil temps in the 240 range, but since I run Mobil 1 - Racing 4T, my oil redline is 280 degrees.  I have 400 plus hours on my motor currently.  I bought the plane with 70 on the hobbs.  The oil temps have never trended differently for me.  

At 235 you are still well within the green, so not to worry.  Just monitor it for higher.

I still have them connected to the cross tube but now working on changing the pedals and building the brackets to place them on the floors.  The Grove sound like a good way to go.  thanks

Paul:

The avids and the kitfoxes are quite different in the brake rudderbar setup that each use.Typically the kitfox has the top of the brake pedal tipped very far forward ahead of the rudder pedal portion.rudder bars are also usually a lot  taller (depending on the model)by contrast to the avids which are  very short and everything cramped up.  http://www.avidfoxflyers.com/index.php?/topic/530-go-kart-to-matco-brakes/ This was the best answer I could come up with in terms of giving the avid a decent working and powerfull  brake setup. Joey has done over 1000 take off and landings with his plane.

  Mike

Any updates?  I'm very interested in this.

All the information I posted is from the guy who sells the UL670, so bear that in mind.

I've been considering different engine options as well.  The 582 just doesn't seem to be the best choice for me.

I have looked into alot of conversions, the price is the largest factor to me and right now all engine conversions are off the table so I am trying to work with the 582.

One interesting engine I have looked at is the new AeroVee 2.1 VW engine.  It's at a great price point if you know how to assemble an engine, has a unique carb design that works very well and produces 80HP and more impressively 127ft-lbs of torque at cruise and it weighs 151lbs installed.  The TBO is 1,000 hours and the average overhaul is $200-$500, worst case scenario, replacing all the internals and cylinders being $2,000

The biggest issue lies in the propeller choices, they are limited.  Although I hear that IVO may soon have a kit to convert a 582 propeller to this VW engine with the use of an adaptor.  This will include the IVO IFA Ultralight and Medium props

I have also heard that AeroConversions produces a FWF kit to adapt this into a Kitfox IV if you ask them.  Not sure if this is true or not but there is one on YouTube supposedly.

I have a brand new Corvette LS-1 motor with an Eagle 383 Stroker Kit, Dart 225cc Heads and a complete Comp Valve train with Holley ECU.  If only I could make it fit into my kitfox

I took the fuel pressure regulator off and installed a piece of 1/4 fuel hose.  I started the engine and then turned on the fuel pump without the regulator.  I got an immediate change in noise from the engine and a drop in RPM and an increase of about .8 GPH fuel burn.  No apparent change in EGT's or CHT's.

I then re-intalled the new FPR and did the same test, no change in noise or drop in RPM, a slight increase in fuel burn of .1-.2 GPH and the engine ran smoother.

I think the pump is moving too much fuel, but I cannot get in to read the part numbers off the pump, it is encapsolated in a custom aluminum heat shield on the firewall