Model 5 Continental Performance

[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!