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503DCDI on a MK4 STOL

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Posted

Has anyone flown or known someone first hand who has a MK4 with a Rotax 503DCDI installed? Please provide some info. Thanks

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Posted

No, but I'd like to know how it does also. Since I am putting a 55hp Hirth on a model 2 Fox it would be comparable in performance. I know from experience that the Hirth 3202 and Rotax 503 both burn about 2.5-3 GPH at cruise power. I flew a 450lb challenger with a Hirth and a Rotax both and performance was awesome. But gross was around 900lbs in both cases.

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Posted

My thinking is that it would be quite a bit underpowered.  I have flown in a Kitfox 4 that had a 503, and was really surprised how well it did.  But the Kitfox 4 has a longer wing with a faster flying type of wing as well.  Also, the Kitfox was pretty light.  JImChuk

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Posted

I guess I'll find out how one flys with 55HP. Might be another one of those expensive lessons, but I am pretty much committed now to use the Hirth. It can be made into a 65 HP if needed with some minor changes so all is not lost. Except my mind.

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Posted

Pretty sure the "Bandit" is a light weight MK IV.  I also think that Bandit on here flies his with the 503.  I am sure it would fly fine solo but not sure I would want to try going anywhere short at gross weight with a 503.

 

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Posted

Has anyone flown or known someone first hand who has a MK4 with a Rotax 503DCDI installed? Please provide some info. Thanks

I have a MK4 Bandit with a 503 Rotax. It has been a great engine. I did build the Bandit lite and simple. Like all other Avids and Kitfoxes it is a good single place airplane. I am burning 5 gph in it. In cruise I am running it at 6000 rpms.

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Posted

Just curious Mark, what is your speed at that 6000 rpm.  I guess where I'm going is if someone was thinking, can I go with a 503 or should I opt for a 582.  The other question may be, the plane I'm looking at has a 503.  Will it be enough power.  What is your empty weight?   JImChuk

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I guess I should give a little more back ground. I'm new obviously. So I made my first mistake of putting this in the wrong category.  I have owned a model C in the past with a 532. I have not finished my pilots license in over 30 years. I have never been up in a Fox or Avid yet. I purchased a MK4 a little over a year ago and have been rebuilding it. It had (has) a 582 blue head. I at the point I need to decide what engine I'm going to use. The 582 had a C box but I acquired and E box to avoid the firewall modification. I think it will bolt up to the 503 also that currently has a B box. I have a 4A084 military engine I have been messing with with a gear reduction system attached, but it's kind of a long shot. I might have a chance at a 912UL, even at a good price it can get expensive just to get it on the acft. I like the 503 idea because it eliminates one system and possible problem (coolant). I read an article of a guy describing his flights with his club all over the country in a model C ? with a 503 and he said he had no complaints. That's all I know of it myself.

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Posted

The E gearbox should fit on either the 503 or 582.  The 503 will give you about 20% less HP at full throttle then the 582.  You can guess what that will do to your take off or climb performance.  If you are cruising around at 75 or so, I doubt that the fuel burn would be much different from one to the other.  Maybe even better with the 582 as you won't be pushing it very hard.   Cruising around at 5200 or so I used to burn about 3 1/2 gph with the 582.  If you really want to go with the 503, I would go with the B box and put the starter on the back.  The box for the firewall really isn't that hard to make, and you will loose 10 -12 lbs.  And you would be loosing it right out on the front of the plane.  Avids are almost always on the nose heavy side as it is so that would help with the CG.  I've never owned one, but from what I've read about the 084, it doesn't really produce as much power as a 447.  Even though some will claim it does.  Usually they are the people who are trying to sell them.  A friend of mine drove about a 1000 miles to look at one in a single seater "ultralight".  The seller had told him how good it took off and climbed.  The guy flew a short flight in it for him, and when the guy landed, my friend gave him a few choice words and got back into his truck and drove the 1000 miles back home.  It really was a dog.  I wouldn't even consider putting it on  an Avid.  One last thought, if you decide to sell the plane at some point, it will probably sell much easier with the 582.    JImChuk

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Posted

Just curious Mark, what is your speed at that 6000 rpm.  I guess where I'm going is if someone was thinking, can I go with a 503 or should I opt for a 582.  The other question may be, the plane I'm looking at has a 503.  Will it be enough power.  What is your empty weight?   JImChuk

Ground speed is 69mph. Empty weight is around 480lbs. I run my engine pretty hard, below 5900 rpm its  flies a little tail low. When I give rides I run a little below WOT. I like this combination, but I am easy to please. I just learned the characteristics of my airplane and learned to fly it. I don't worry about all the technical stuff. Just like Leni said, I have spent 1100 hrs in the seat so I am comfortable flying the Bandit with a 503 in it.

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Posted

Just last night I was looking at a video I posted to utube years ago.  My flying partner and I were flying the MK IV with a 582.  He was learning how to fly the plane and we were on skis.  Airspeed was just under 75, and rpm was at 5400 something.  Airspeed was pretty accurate.  That plane weighed 585 lbs empty.  The two of us together had to be all of 400 lbs with the winter clothes and all plus we probably had 10 or 15 gallons of fuel.  Total weight would have been around 1050 or more.  I think between our posts Mark, (bandit) one can get an idea of the difference between the 503 and 582.  Nothing against your plane Mark and I really hope it doesn't come across that way, but if the original poster wants a real life comparison, maybe he just got it.  I get a bit silly at the end.  Maybe it's the joy of realizing I'm still alive!   :lmao:JImChuk

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Posted

Just last night I was looking at a video I posted to utube years ago.  My flying partner and I were flying the MK IV with a 582.  He was learning how to fly the plane and we were on skis.  Airspeed was just under 75, and rpm was at 5400 something.  Airspeed was pretty accurate.  That plane weighed 585 lbs empty.  The two of us together had to be all of 400 lbs with the winter clothes and all plus we probably had 10 or 15 gallons of fuel.  Total weight would have been around 1050 or more.  I think between our posts Mark, (bandit) one can get an idea of the difference between the 503 and 582.  Nothing against your plane Mark and I really hope it doesn't come across that way, but if the original poster wants a real life comparison, maybe he just got it.  I get a bit silly at the end.  Maybe it's the joy of realizing I'm still alive!   :lmao:JImChuk

Jim, 

You are correct,  the Bandit with a 503 might not be a good 2 place airplane.  My Champ is a super airplane to give rides in. Plenty of room, great visibility. Climb out isn't anything to brag about, but it sure is fun to fly.

 

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