Model 5 Continental Performance

[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.