Model 5 Continental Performance

[Steve-TX]

Hi, Team Kitfox folks. Here’s my story: I wanted an affordable float plane and bought a Kitfox 5 (1550 gw) with a Continental 0-200 (experimental 110-115 hp) that came with Lotus 1450 amphibious floats. I’ve been flying it on wheels to get some tail-wheel time for over a year now and thinking it’s time to get the plane and myself ready for floats. I’m checking out schools for the rating and there are so many to choose from. The part I need advice for is the Lotus 1450 floats. I called a previous owner to learn what he learned and he basically said “forget it, it won’t work”. I was a bit in shock by this advice but nonetheless I was in the listening mode trying to learn from his experiences. He said the plane was too difficult to get off the water and considered it a failed project. He said he believed he hired the right people to rig the floats and that he had lots of float plane time. I think he was operating out of a near sea level location and not sure what the outside temp/humidity was. I didn’t ask him his weight but he mentioned something that made me think he was not that heavy. I’m close to 200 myself. The person I bought the floats from said he installed the floats but never water tested them. My plan is to remove the amphibious hardware and see if it will get off the water at a reduced weight. I can stay under mgw (1500 lb) limit with just myself on board. If that works out, I will be content and may decide later to add the amphibious gear back to the floats. I have heard lots of success stories of the Kitfox 4 on floats but my heavier 5 model seems to feel more like Cessna 150 performance. I rode in a KF 7 and it seemed to have better performance with the more common Rotax 912. I was recently flying with my son on a hot Texas day within 200 lb of mgw with all our gear and the lack of performance made me wonder how it would do with floats installed. Wondering if anyone knows of a success story concerning my plane and floats (or something similar) or has any advice to share before I begin this project. Thanks in advance. Steve J, Texas KF-5, Continental 0-200, Whirlwind 3-blade prop

[Esser]

I think if your model 5 has the same performance as a 150 you have an issue wih your plane somewhere.

[Steve-TX]

Possibility. I’ve wondered that myself. Compression checks were good recently. Cruises about 100 mph groundspeed with no wind. Prop pitch seems to give reasonable rpm on takeoff (around 2600) but is ground adjustable so I could try a different pitch. She’s just a dog when it’s hot.

[Av8r3400]

What does the plane weigh?

(I moved this conversation to it's own thread)

[Steve-TX]

W&B records show 858 lb. empty weight. Thanks.

[Esser]

Hmm for an o-200 powered plane that’s a decent empty weight. I don’t honk you’re making advertised HP or something...

[Steve-TX]

Good point. I’m not sure how to test that though. Please let me know any ideas to test that out. I’m not an A&P but I know some who are and perhaps I can bring it up at my next EAA meeting.

[Esser]

I’m not really sure either. My first guess would find a great running O200, put the prop on that engine and compare static rpm....

[Steve-TX]

Thanks, Josh. That seems do-able! I will start looking for an opportunity to do that.

In the back of my mind, I’m wondering if it may be an incorrect perception on my part. I used to fly fighters so perhaps my brain is comparing apples and oranges. However, I had a KF 7 instructor tell me the same thing (performance of a C-150) compared to his plane. And struggling to hold 5500’ altitude on a hot and humid Texas day (around 8500 density altitude) at about 1300 lb gw makes me just wonder.

Anyone know of any successful stories of KF 5 with 0-200 on Lotus floats? Or any KF 5 with any engine option on any floats for that matter.

[n85ae]

Paul Leidl in Minnesota has an IO-240B Series 5 on floats, haven't heard from
him in years on the forum, but if he's out there he would know. I like my
airplane with IO-240B and at light weight it is a rocket, BUT my impression is
the wing doesn't work well at heavy weight, and that sucks all the performance
out of the plane.

Here's my thoughts after 10+ years flying my Series 5 with an IO-240B, and
I do not have performance problems with mine. I can get close to 2000 fpm
on a good day solo, and I can hit VNE in level flight at full power.

Light weight with IO-240B I get very good performance, heavy, it's not as bad
as a C-150, but I would not call it good either. The original SkyStar sales video
where they say if "you ever wanted to fly the bush in a SuperCub, have we
got a plane for you ..." is a bit BS. Put a load in the plane and get near max
weight, it flies terrible. It is a truck with a heavy load.

I think the 912 weight engine probably works better in the air frame ... I
personally think it's the airfoil, and it works poorly at higher loadings. I'm
sure somebody will dispute this, but that's what I believe.

The other thing is the fuselage length is too short relative to the wingspan,
and it causes a lot of the constant annoying rudder pedaling you have to
do on a choppy day. I used to build and fly RC Sailplanes, and the Kitfox does
exactly the same thing, which in an RC Sailplane I would have fixed by
making it longer.

Next I would not put floats on my airplane with IO-240B since I know the
weight would kill it.

Jeff

[Steve-TX]

Paul Leidl in Minnesota has an IO-240B Series 5 on floats, haven't heard from
him in years on the forum, but if he's out there he would know. I like my
airplane with IO-240B and at light weight it is a rocket, BUT my impression is
the wing doesn't work well at heavy weight, and that sucks all the performance
out of the plane.

Here's my thoughts after 10+ years flying my Series 5 with an IO-240B, and
I do not have performance problems with mine. I can get close to 2000 fpm
on a good day solo, and I can hit VNE in level flight at full power.

Light weight with IO-240B I get very good performance, heavy, it's not as bad
as a C-150, but I would not call it good either. The original SkyStar sales video
where they say if "you ever wanted to fly the bush in a SuperCub, have we
got a plane for you ..." is a bit BS. Put a load in the plane and get near max
weight, it flies terrible. It is a truck with a heavy load.

I think the 912 weight engine probably works better in the air frame ... I
personally think it's the airfoil, and it works poorly at higher loadings. I'm
sure somebody will dispute this, but that's what I believe.

The other thing is the fuselage length is too short relative to the wingspan,
and it causes a lot of the constant annoying rudder pedaling you have to
do on a choppy day. I used to build and fly RC Sailplanes, and the Kitfox does
exactly the same thing, which in an RC Sailplane I would have fixed by
making it longer.

Next I would not put floats on my airplane with IO-240B since I know the
weight would kill it.

Jeff


Great stuff, Jeff. Thanks for that insight. I’m new to the experimental community and opinions like yours are extremely valuable to me. Yes, your plane sounds like a great performer overall. I live on a lake in Texas and I just see runways in every direction in my back yard. I do like my Kitfox and with just me in it on a cool day I have no complaints. But if I don’t find a way to put it on floats I plan to enjoy it for a while but start looking for something I can keep docked in my back yard. I will try to get in touch with Paul L. Thanks again!

[ken nougaret]

I'm flying a model 7 with a stock O-200A. On a cooler florida day i can climb 600'/min at 1550 gross. In the heat of florida summer, 600'/min at around 1350 lbs gross. And my cruise is about 100 mph. Last year, july 4 week, i remember climbing to 11,000' to get on top of clouds in pennsylvania. I know it didnt have a lot left in her past that.

[Steve-TX]

I'm flying a model 7 with a stock O-200A. On a cooler florida day i can climb 600'/min at 1550 gross. In the heat of florida summer, 600'/min at around 1350 lbs gross. And my cruise is about 100 mph. Last year, july 4 week, i remember climbing to 11,000' to get on top of clouds in pennsylvania. I know it didnt have a lot left in her past that.

Thanks for that information, Ken. Another great data point that I very much appreciate. Our configurations are very close I think: same basic airframe, same engine, same prop (My Whirlwind has 3 blades but I don’t have diameter measurement handy). Can you let me know:
1: model Whirlwind you have (or prop diameter)
2: pitch angle you have your prop set at?
3: static RPM you get at that prop setting?

I haven’t changed mine and not sure what pitch its set at but perhaps I need to look closer at it. The builder notes recommend 11 degrees. I did a static engine run back in February when cooler and got about 2500 rpm. It feels very strong on initial acceleration but less so when near takeoff speed. I will plan to do a climb rate check next time I fly for comparison to your numbers. It’s quite hot & humid here in Fort Worth this time of year. I believe I read that the Model 7 is slightly better aerodynamically than the 5 but I think our numbers won’t be very far off.

[ken nougaret]

It does sound like our numbers are similar. I have the WW 2 blade 72". I cant remember if im pitched 11 or 13. I'll check tomorrow. My static rpm is about 2700. I love flying my plane and the O-200. I havent flown a cessna 150 so i cant compare. My only regret is if i ever wanted floats i think id be too heavy. But hey, it wouldnt fit in the garage if it were on floats.

[shawnspeak]

My static rpm is about 2700.

I thought the recommended static RPM for an O200 was somewhere around 2300? Your 2700 static and Steve's 2500 seem a bit high to me considering that the max RPM is 2750. Might be something to check into.

[ken nougaret]

Thanks Shawn. I believe you are correct. I'll play with the pitch.

[Steve-TX]

I thought the recommended static RPM for an O200 was somewhere around 2300? Your 2700 static and Steve's 2500 seem a bit high to me considering that the max RPM is 2750. Might be something to check into.

I like that idea too. I’ve been meaning to get more familiar with manually adjusting the prop pitch anyways.

[Steve-TX]

A follow-up. I changed my WD prop drive to 11 degrees. It measured 8 degrees before I changed it. A static runup resulted in about 2250 rpm, after the change. I flew it and although takeoff performance was noticeably less I gained about 10-15 knots in cruise. WOT during flight got about 2400 rpm. I plan to change the pitch to 10 degrees to get the static rpm to 2300.

Back to the float idea. I think my plane may get off the water once I install the Full Lotus 2350 floats with the amphibious gear removed. I should try it on a cool fall/winter day versus in the heat of the summer for best success chances. I’d like to get some advice and help making sure the rigging is right. Not a lot of float planes and pilots in TX. I will get the factory manuals but and follow them to the best of my ability. If any of you feel up to the challenge of helping me with this project via phone/Skype or even in-person, please let me know. I can’t imagine I’d be the first Model 5 with an O-200 on floats, or am I?

Once I install the floats, I may have to reduce the blade pitch again.

[airlina]

You should be able to get to rated RPM (on my continental IO-240 it is 2800RPM) so the 2400 RPM you are seeing with full power level flight is too low, you should be seeing more like 2750 which I believe is the rated limit on the O-200. Keep playing with the pitch till you can achieve this. My full power static RPM is about 2350 RPM and rated RPM of 2800 is achievable at full power level flight. I have a Sensenich wood prop . Bruce N199CL

[av8rps]

I fly a 80 hp 912 ul on amphib floats with an IVO IFA prop, and it works great. In many regards it is a little hotrod. But it's under 800 lbs on the floats. Keeping the weight down is a huge advantage with the smaller wing area of the Kitfox, which is the primary reason the 4 is easier to make work on floats.

However, I can't see any reason that an 0-200 Model 5 won't work as a floatplane. It will probably never perform like the 100 hp 912 model (much lighter) but it should still make for a fun floatplane.

But, 2350 floats are way too large for a Kitfox. 2350's are for a Husky or Glastar. 2350's would be large even for a 150 hp SuperCub. With a Kitfox in the 850 range empty weight (on wheels) I would suggest a 1550 to 1650 lb float (buoyancy being typically higher than number on float). Paul L's IO-240 Kitfox flew on Murphy 1800 amphibs if I remember correctly. And those were probably a bit larger than he really needed, but he did get them to work.

With that said, once you have properly sized floats on the plane, you should set the prop pitch so that you know you will overspeed the engine with wide open throttle when straight and level. Yes, it's going to be set really flat. And yes, you are going to lose cruise speed. But it's a floatplane so you won't really care with all the fun you are going to be having :)

You need all the takeoff power you can get. Floatplanes take a lot more power than a landplane. They have to plow through the water to get on the step, and then have to break the suction of the water in order to leave the surface. Land planes have none of that to deal with, so getting a floatplane set up properly can be difficult by comparison. But I can assure you after waterflying for more than 3 decades, it's worth the effort!

[Steve-TX]

I fly a 80 hp 912 ul on amphib floats with an IVO IFA prop, and it works great. In many regards it is a little hotrod. But it's under 800 lbs on the floats. Keeping the weight down is a huge advantage with the smaller wing area of the Kitfox, which is the primary reason the 4 is easier to make work on floats.

However, I can't see any reason that an 0-200 Model 5 won't work as a floatplane. It will probably never perform like the 100 hp 912 model (much lighter) but it should still make for a fun floatplane.

But, 2350 floats are way too large for a Kitfox. 2350's are for a Husky or Glastar. 2350's would be large even for a 150 hp SuperCub. With a Kitfox in the 850 range empty weight (on wheels) I would suggest a 1550 to 1650 lb float (buoyancy being typically higher than number on float). Paul L's IO-240 Kitfox flew on Murphy 1800 amphibs if I remember correctly. And those were probably a bit larger than he really needed, but he did get them to work.

With that said, once you have properly sized floats on the plane, you should set the prop pitch so that you know you will overspeed the engine with wide open throttle when straight and level. Yes, it's going to be set really flat. And yes, you are going to lose cruise speed. But it's a floatplane so you won't really care with all the fun you are going to be having :)

You need all the takeoff power you can get. Floatplanes take a lot more power than a landplane. They have to plow through the water to get on the step, and then have to break the suction of the water in order to leave the surface. Land planes have none of that to deal with, so getting a floatplane set up properly can be difficult by comparison. But I can assure you after waterflying for more than 3 decades, it's worth the effort!

Av8rps, thank you for that information and renewed motivation. Yes, I can easily sacrifice speed with floats. Many, many apologies as my Lotus floats are 1450’s; not 2350’s as I mistakenly wrote. Only a 900 lb error! A previous owner said he couldn’t get it on step and thought he had the right help with rigging. I’m not totally convinced my heavier Continental O-200 is performing as it should be yet but I’m playing with prop setting to see if adjusting it helps. I’m not an A&P and I’m fairly new to plane ownership - 1 year. I’ve had a conversation with Kitfox and the nice lady I chatted with did say the Rotax 912 engine weighs in 80 lbs lighter and if I could start over knowing what I know now, that would be my engine for that very reason. If I can get my plane safely in the air with no amphibious gear, I’d be a very happy Kitfox camper!

[Maverick]

My last KF5 had an 0200-A with a 70" three blade Ivo-Prop. I set the pitch according to the RPM. Initially, I had the pitch too high and was getting 2450 RPM and 125 MPH. I flattened the prop so max RPM was 2750. My speed came down to 115 but my climb improved significantly. I generally cruised at 2550 RPM @ 110 MPH. My flying buddies were running 912ULS and could out-climb and out-run me so with this build, I'm using the 912ULS.

[mr bill]

To get more power from an O-200A, install pistons from the O-200D. They raise compression from 7:1 to 8.5:1, you will get a real 100hp.

[Steve-TX]

My last KF5 had an 0200-A with a 70" three blade Ivo-Prop. I set the pitch according to the RPM. Initially, I had the pitch too high and was getting 2450 RPM and 125 MPH. I flattened the prop so max RPM was 2750. My speed came down to 115 but my climb improved significantly. I generally cruised at 2550 RPM @ 110 MPH. My flying buddies were running 912ULS and could out-climb and out-run me so with this build, I'm using the 912ULS.

Hi, Maverick. I seem to be following your path and right now I’v got too much prop pitch. I’ll back it off some by reducing pitch to get better numbers. Your experience with O-200 vs 912ULS makes me think that if I am not successful getting off the water like the previous owner then I may have to make a drastic change and consider swapping engines and/or floats.

[Steve-TX]

To get more power from an O-200A, install pistons from the O-200D. They raise compression from 7:1 to 8.5:1, you will get a real 100hp.

Thanks, Mr Bill. The previous owner said the experimental engine was rebuilt at a higher hp than stock so the oil pressure runs a bit high. My engine records indicate that Dons Dream Machine did the rebuild with 40327 pistons. I’ve tried to confirm if these pistons are the higher compression pistons but no luck yet. I plan to call DDMs to see whay they say. Have a great day.

[Maverick]

Steve,
Were you to swap engines, remember that the wings are swept forward one degree for most non-rotax engines and address the W&B accordingly.

[av8rps]

Hey Steve,

Glad to know those are 1450's rather than 2350's. That should be a good float for your Kitfox. Full lotus floats usually have lots of buoyancy for their rated sizes.

Yes, the 912 will probably do a better job being so much lighter. But with an 858 pound 0200 powered plane on wheels, that is not too bad. I've seen a lot of newer Kitfoxes with the 912 that are in the 850 range. I have a friend that has a Cessna 120 on straight floats with an 0-200 and it performs quite well. And that has got to be heavier than your Kitfox. So I believe if you just get that 0-200 to wind up like it should that it might surprise you. Plus, there are so many mods for the 0-200 to make more horsepower that you will have a lot of options should you find yoursel needing more performance.

I'm looking forward to hearing your results with some prop tweaking.

[Steve-TX]

Steve,
Were you to swap engines, remember that the wings are swept forward one degree for most non-rotax engines and address the W&B accordingly.

I didn’t know that but good information to put in my back pocket for planning purposes. Thanks.