More power than a 582

[herman pahls 9]

I need more engine than the 582 offers for my model 2 now that I am dragging 29" Airstreaks around.

I have already added 9 pounds of lead to the tail so 912 or Subaru will probably not be options.

I tried the 80 HP Jabiru with mixed results but have heard the 85 HP Jabiru is significantly better.

I have not heard much about the Rotax 670 lately.

Have the 670's been working out?

I heard they are very thirsty.

Seems like Leni was working on a 2 stroke option.

Thanks Herman

[akflyer 1427]

I am still working on a fuel injected 2 stroke, but the machinist I had working on the adapter plate figured out what I was doing and he dropped the project like a hot rock.. I am looking for another machinist to make the adapter plate for my "airboat" project now.

 

I am not sure if you could make a shorter mount for the 912 to minimize the nose weight.  You could take the lead out of the tail and put the battery back there too so your not adding dead weight to the plane.

 

I was told the 670 was spose to be better on the fuel burn than the 582 because it was just kind of "loafing" along and not really working hard.

 

I really hope to get my project working soon, but it seems to take alot longer to develope than originally thought.

 

[Av8r3400 1179]

This will be argued, but the best bang for the buck is still a 912.

It's supported, economical, reliable, powerful, light, and most of all, light.

Personally, I've never seen a successful 670 install that was worth the headaches.

[EDMO 1078]

Leni, there was a guy near Nikiski, that made a complete Hi-Vo chain redrive for David Goode - David had it on a boat, before he got his Airdale. If you could locate him, or if I can find his name and address, I'm sure you would have no problem getting him to make an adapter for you, if he is still in business.

He even shared his drawings with me at no charge.

I will look for his info.

EDMO

Edited 30 May 2013 by Ed In Missouri

[6320012s 12]

Leni,

If you have a drawing, I have a CNC Mill and a teenager with time on his hands.

[akflyer 1427]

Dave,

 

Will a detailed hand drawing work, or is an auto cad file better for you?  If auto cad, what version should I save the file as?  We have a CNC plasma table here at work and I have to save the files to acad 2000 in order for it to recognize the file.

 

I have this drawn up and can put in the additional measurements for the bolt hole spacing, or I can have one of the guys do the cad file for you.

 

Thanks

 

[6320012s 12]

would be best to have in a .dxf format drawn to scale.   front and cross section views look to be plenty.  Do you have material?

[herman pahls 9]

Av8r3400

You emphasized the light weight of the 912.

Any idea the weight difference between the 912 and a 582?

My 582 has the inflight adjust ivo, clutch, Hackman , c box which all ad weight.

I would go with a 912 if my model 2 could tolerate the added weight.

I already add 8 pounds of lead to the tail if I use the 29" air streaks.

Years ago some one in Utah or Idaho said that he powered his model 1 Kitfox with a 912 and had to add some tail weight.

Does anyone know who that may be ?

Do the 80 and 100 hp 912's weigh the same?

My model 2 has a never exceed speed of 100 mph and a gross weight of 950.

With the bush wheels this Kitfox is already a single place airplane so why not go with a 912 if the CG works out.

Thanks Herman

[Av8r3400 1179]

There's a couple of guys over on TeamKitfox that have 912 powered early Kitfoxes.

A full install ready to run would weigh near 160 pounds. The difference between the 80 and 100 weight is minimal, maybe 5 pounds?

[Mendlerr 4]

On the topic of the 670, it is alive and well.  Over 70 flying from what I have been told.  Rotax Rick in FL is apparently the authority on the 670 and has redesigned the engine using cageless lower bearings which greatly increases the reliability along with a piston and rod upgrade

 

The UL670 mount to the 582 mount, uses the 582 ignition and is only 3/4 of an inch taller then the 582 due to the RAVE valve.  The weight is also the same on the newer versions of the 670.

 

If you send in a good rebuildable 582, the cost of a brand new 670 (all new parts) is only $3,350.  The new exhaust is around $675.  Without the exhaust your not going to make any more power then your 582, but with the exhaust the power increases to 89HP at 6,900 RPM's which is redline for the detuned UL670.

 

For takeoff (Rotax Rick recommends Warp Drive prop on the UL670) set your static RPM to 6,500-6,600, this will give you around 6,900 takeoff and full 89HP.

 

When your up in the air throttle back between 5,500 and 5,900.  The advantage is with the extra power you can add alot of pitch to your prop and be at the same RPM as the 582, therefore you create much more thrust and your cruise will increase.  At 5,500 RPM's the 670 burns around 4 Gallons per hour, and it burns around 4.5 gallon per hour at 5,900 RPM.  The 670 has no problem turning that RPM as it was originally designed for 7,000+RPM's

 

The TBO time of the new 670 is 450 hours instead of 300.  This is due to the lower fuel burn, Rotax bases their TBO time on the time it takes to burn 1,500 gallons of fuel, Rotax Rick uses this same theory.

 

This is all information I copied from an email conversation with Rotax Rick.  Seems like it's a good deal if you want to stick with the 2-Stroke.

 

Also a complete overhaul of the UL670 is $1,175 and the GreenSky HACman kit will not work with it for some reason, they had bad results.

Edited 31 May 2013 by RMendler

[Av8r3400 1179]

Personally knowing three people who have tried these motors in Avids, none of them are still flying.  One went back to a 582, the other to a 912 and the last quit flying all together after several engine outs.

 

Wouldn't be my first choice.  Just my opinion.

[Mendlerr 4]

Personally knowing three people who have tried these motors in Avids, none of them are still flying.  One went back to a 582, the other to a 912 and the last quit flying all together after several engine outs.

 

Wouldn't be my first choice.  Just my opinion.

Do you know when the engines mentioned were purchased and installed?  From what I have been told alot of time has been spent fixing the issues mentiontioned on other forums.  The newest UL670 was released recently and supposedly is a much better engine.  I read a build thread on a weight shift control forum where the new UL670 was used and the WSC would rocket off the ground much better then with a 582.  If I can find the link on google I will post it.

[Av8r3400 1179]

The lat one was a year or a little more ago.

I believe all three would agree that when the ran well they were amazingly powerful, but required constant tinkering. The Reliability of a 582 was just not there.

One of the guys was a very experienced two-stroke guru (he's still our go-to guy on them).

[BryceKat 125]

What was the constant tinkering they were having to do? Thanks, Bryce

[Mendlerr 4]

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

Edited 2 Jun 2013 by RMendler

[Av8r3400 1179]

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.

[Mendlerr 4]

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.

[Av8r3400 1179]

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

[Mendlerr 4]

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.

[BryceKat 125]

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

[Av8r3400 1179]

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

[herman pahls 9]

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

[1avidflyer 1983]

There are 2 Kitfox 4s on ebay right now with 912 engines for sale. Jim Chuk

[akflyer 1427]

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

There are a few guys that have put the Hirth engines in KF / Avids, but I have damn sure not heard any raving about them other than from the dealer about them being the greatest thing since sliced bread.

 

When looking at older 912 engines, MAKE DARN GOOD AND SURE you look at the service records as there are a ton of "service" bulletins on them, some mandantory, some not, that could make your "awesome deal" on a 912 or a 912 powered plane turn into a money pit REAL quick.  Some are cheap and easy, others are thousands of bucks to comply... Of course, as an experimental, you dont have to comply, but how much of a warm and fuzzy do you get to have when your flying over hostile terrain knowing that you engine probably (or could have) a KNOWN issue.

 

I am not knocking the 912 (settle down Larry   ) just making you aware of some potential issues that you could be faced with.  If I could go out and buy a 912 today I would be bolting one on... But if I am gonna spend that kind of money, I will just rebuild my Pacer right now..

 

[Mendlerr 4]

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

No doubt the prop makes a huge difference, ask me how I know.

 

I emailed Rotax Rick again just to ask another question, why limit the 670 power to 89 when from the factory it makes 120+.  He had a good answer.  When he emails it doesn't always make sense and I have to ask him for clarification.   Not sure if it's a language barrier or typing really fast but here is what he sent me last night after I posed the question "why limit the power so much".  If it doesn't make alot of sense let me know.

 

Look at the big picture. The Rotax Ski Doo & the Rotax Sea Doo from the early 1990's through 1999 were about the same engine design. Same intake, cylinders, crankshaft ( intakes rods, main bearings ,rod bearings ( upper & lower) etc ) A 1998 Rotax 670 Ski Doo & a 1998 720 Sea Doo are about the same engine. The Ski Doo 670 made 132 hp The larger Sea Doo made only 85 hp. WHY It was detuned because it could be ran wide open for mile after mile. If you tried that with a Ski Doo you would kill yourself .

In other words I can build a 670 that would give you 175 hp for a VERY short time. I can give you a 670 that will make 89 hp for a limited time, Back the 670 down to a cruise of 60 hp and it will last a very long time.

Keep in mind a 670 is only 10 lbs more than a 582 but 24 more hp. HOW CAN IT DO THIS, ONLY VERY CAREFULLY.

Limit the throttle to what you need, then run it like your 582 , You will get over the trees with ease and cruise at 1 gph less in gas. Not a bad deal. Keep in mind we use far better rods than a stock 582, plus better pistons and we surface  and deck the head & cylinders . All this makes for a better & safer engine , BUT it has it's limit. If I was not protective of my customers I would be selling these at 105 hp .

 

I am not trying to sell the 670 by any means but it seems like a good option for us guys who cannot afford the 4-strokes and need alot more climb.  Upgrading to the 670 WILL improve the cruise but only if you change your prop to a larger one with more pitch. 

Edited 5 Jun 2013 by RMendler