Float question

[PapuaPilot]

Has anybody used AirComp brand floats on a Kitfox or done the research to see if they would work?

[av8rps]

I know quite a bit about floats, but do not recognize that name. Any pictures of what they look like? Or their website?

[PapuaPilot]

There is a new / never used set of the SF1800 amphibious floats for sale on Barnstormers. I am wondering if they could be installed on my KF5.

There isn't a lot of info at the website and they haven't answered the phone yet. They do have a 2017-2018 price list, so it appears they are still in business. I will continue to attempt to contact them today.

These floats are different then most amphib floats. They have tailwheels (two wheels at the back of the floats), so the only part that retracts are the main wheels. They claim it won't flip over if they are landed gear down in the water.

One concern would be getting enough angle of attack for takeoff because the tailwheels limit the deck angle. I am guessing the aircraft will need to mounted
with at least 5 degrees additional nose up.

FYI I have lots of float experience in C-208 and C-206, most of it on the Wipaire 8000 & 4000 amphib floats.

Here is the website:
http://www.aerocompinc.com/floats/floats.htm

Here are some pictures of their floats:

[fastfred]

[Try contacting this guy. Ken Smith .harborsport@hotmail.com (.harborsport@hotmail.com)

He mostly just does light sport float set up. He set up my KF7 for them

[PapuaPilot]

He mostly just does light sport float set up. He set up my KF7 for them

What kind of floats do you have Fred?

[fastfred]

waterborne Float system

[av8rps]

Phil,

Sorry for the delayed reply.

Ok, after looking at the picture I do recognize those floats and the name Aerocomp. I actually thought they were out of business, but apparently not. They were used on Merlin aircraft, which is what appears to be the plane in the picture you posted. I have never flown those floats, so I really can't say anything good or bad about them except that it seems whenever you see a set of them up for sale they are not a lot of money. So that makes me think they don't work all that well. But maybe that is a wrong assumption. I do remember watching an old video called "Flightline" with Hank Austin years ago where Hank and a company pilot went out and flew a 582 powered Merlin on amphib Superfloats and it looked like it did really well. But again, it was just a video.

For what it is worth, here's why I would be skeptical of those floats:

- As indicated, the ability to rotate will be limited due to the limited angle of the rear of the floats, as well as the tailwheels dragging. If that worked so well wouldn't everybody be doing it that way?

- Landing gear down... Many think the nosewheels down are what make an amphib float flip over when the gear is left down, but it's not. It is the main gear grabbing and overcoming the forward buoyancy available, causing the bows to dive under water and flip the plane. EDO proved that when they built a prototype amphib 1320 float for the J3 Cub. It had fixed nosewheels, so only the main gear retracted. Jay Frey said the float worked well with the nosewheels always in the down position, but the float was never put into production for other reasons. This video also shows well how the main gear causes the flip https://www.youtube.com/watch?v=ZrwvyM9NuqA So I don't see any reason to have the main gear retract in front of the step area, and doing it that way would make me suspect if that would work well, as it is in the general area the plane needs to ride on when on the step. Again, no experience with the float, but it is likely that any disturbance of water in that area of the float would delay or stop the plane from getting on the step.

- I'm not sure of the strength of the float, or of the weight. But I had heard way back when that they were not built very strong and yet they were heavy, as there was no advanced technology used in their construction. If you investigate the aircraft that were built under by the Aerocomp company, you will find similar results as the floats... not many flying, and when you find them used they are less $$ than most. I believe the same company (or people) built the Airshark amphib. It was a really cool looking amphib, and it was fast for a seaplane. But I saw it at the Oshkosh Seaplane Base and after it landed it couldn't take off. It also had a really poor useful load because it was so heavy. You do rarely see an Airshark for sale, but it is always with odd circumstances. As an example, we have on used as an airport sign in Door County Wisconsin. But I gotta say it looks cool. Airport guys say it makes a better sign than an airplane.

Ok, so once again I want to qualify my statements. I have never flown those floats, so I'm just sharing what I've heard or seen after being around experimental float planes for the last 40 years. So take it for what free internet advice is worth ;)

If I were going to float a newer Kitfox and wanted to keep my budget under control I would rather go with more of known commodity, such as a Zenair 1450 amphib float. We know they work, are of conventional design, are a well proven design, etc, etc. And they are pretty reasonable if you build them yourself (15k?) But you do have to build them, and some say it is as big of a project as building the plane. :eek:

My favorite floats are the CZ 1300 amphibs, but they are nearly impossible to find as only a handful of them were built (it is essentially just a scaled down Wipaire 2100 amphib). New they were a steal at 16k, but used ones are in demand so they will typically run in the low to mid 20ks, if you can find a set.

Clamar floats are also good, but generally are in the mid 30k price range by the time you get them on the plane.

And of course, the Aerocet 1500 amphib as used on Carbon Cubs are also available, and are a great float. But you will pay 50k for a set. I like my Aerocet 1100's on my Kitfox 4, so I know the 1500's would be a great float.

I hope this might help you find the best float for your Kitfox. A Kitfox makes a great floatplane, so if you have to spend a bit more for a good float, it will be worth it in my opinion as you will have a better than average amphib floatplane. And it will still be much less money than something like a Supercub on amphibs.

[av8rps]

How funny, I was just looking at Barnstormers under the Float Plane category of Experimentals and there is Rans S7 that has a set of Cz 1300 amphibs on it, and the ad says he will sell floats seperately!

There would be a great set of floats for a newer Kitfox. You might get those for less than they were new as I know that plane, and the floats have had some repairs to them. Anyhow, just thought I'd mention it. Those floats rarely are available.

[PapuaPilot]

Paul,

Thanks for your detailed reply. I have already to decided to stay away from these for the reasons you have mentioned

In the meantime I talked to Ken Smith (that FastFred mentioned in the thread) and he said to avoid these floats - poor quality, heavy, etc. His website says the same thing.

I'm a little confused about what you said about the floats on the Rans 7. The ad says they are 1500 floats, but you say they are 1300. :confused: What is the brand and buoyancy rating of those floats?

[av8rps]

The CZ 1300 floats are commonly referred to as 1500's as they will easily handle a 1500 lb gross weight aircraft. The confusion of how float manufacturers name or rate their floats comes from the FAA rule that each float has to support 80% of the aircraft gross weight. So when manufactures tell you they have a 1500 lb float, if done according to the FAA rule, that float wohld probably support an 1800+ pound aircraft.

Unfortunately, not everyone rates floats the same, so many times you won't know what a float will support until they are put on a plane and tested in a real world environment. In the case of the CZ 1300 float I know for a fact they will fly a 1500+ pound aircraft as I've flown them at those weights. I consequently I have a set of CZ 1300 amphibs for my Highlander as I feel they are the best float for my plane, especially for the $$.

Fyi, Ken Smith helped the Czechs that created that float (the same company that built Zenair floats commercially for a few years, but then went off on their own with the 1300) fix many original issues with the prototype set. Ken and I are friends and have had lots of conversations about floats. His personal Rans S7 flies on CZ 1300 amphibs. Ken states on his www.Harborsportaviation.com website that the 1300 is at least a 1400. So again, the float is a really great float, has the best gear I've seen on an LSA float, and is the proper size for most any newer LSA grossing 1400-1550 pounds.

But for anyone wondering, the CZ 1300 is too large for Kitfoxes prior the the Model 5. The floats will also look huge on Model 1-4 Kitfoxes, being obviously too large for the plane. Performance also would be poor due to being too large for the earlier airplanes.

But for Model 5 through 7 Kitfoxes they are about perfect imho :)

[PapuaPilot]

Thanks again Paul. What do you know about he damage and repairs on the S7 CZ floats?

[av8rps]

I see that plane a few times a year. He sometimes wins takeoff contest at one of our seaplane fly ins, so the floats work well. He has bed liner type paint on sides of floats which makes me think there may have been damage? But the more I think about that, he's a super practical kind of guy, so maybe he did that to avoid rash from docks? Best to just ask him if they've ever been damaged, as maybe they haven't been.

[av8rps]

Phil,

I just noticed your Model 5 is Continental IO-240 powered. Is that the plane you want to put amphibs on? If so, what is your Kitfoxes empty weight currently on wheel gear?

I ask all that as empty weight plays a huge part in setting up an amphib and there is much more to know than when setting up a 912 airplane.

Paul

[PapuaPilot]

My current EW is 885, UL is 665.

[av8rps]

885 empty is pretty light for an Io 240 powered Kitfox if I remember correctly. I wish I could remember Paul Liedl's 240 powered Model 5 empty weight as he put his on amphibs and I think he was around 1250 empty by the time he got his Murphy 1800 amphibs bolted on. I remember questioning if the floats would be too big, but he said he needed that as he moved his gross weight to 1750 so he could have a 500 pound useful weight when on floats. Initially he was disappointed with performance, but eventually found the right prop and flew it a bunch of years. I can't find his telephone number, but he sure could help shortcut your process if you could talk to him. He is from Minnesota and used to be on our forum, maybe still is. I saw his plane for sale recently, maybe he still has the floats?

Recognizing a bit late that your Kitfox is Continental powered, I hesitate to be so confident in using those CZ 1300/1500 amphibs. They may be a bit too small for your plane with the Continental engine. I hope I didnt send you down the wrong rabbit hole. The 912 powered airplanes are what I'm most familiar with.

[PapuaPilot]

Thanks again. If I do install floats I really want something that will handle the 1550 pound GW. It sounds like you are saying the CZ floats work best at weights well below that.

[av8rps]

Ironically, I saw the CZ 1300/1500 amphib floats for sale under a new name at OSH. And I also saw they are offering the floats in a 1500 and 1700 size. I do think the 1300/1500 would work with the larger engines, but the 1700 would be much better. Check them out at www.zfloats.com.

And if I can lay my hands on Paul Liedl's number I will get that to you. I'm convinced he could really help you by sharing his experiences with floats on his 240 powerd Kitfox.

[PapuaPilot]

Hey thanks. I took a quick look, the website doesn't have much info yet, but it does have a contact number. :)

[PapuaPilot]

885 empty is pretty light for an Io 240 powered Kitfox if I remember correctly.

He said he needed that as he moved his gross weight to 1750 so he could have a 500 pound useful weight when on floats.

I worked hard to get a low empty weight: Catto prop, B&C alternator, no vacuum system, Garmin G3X Touch, LED lights, etc. I would change to a Lithium battery, but I am using the Odessy battery in the tail to get a good EWCG.

Do you know how Paul Ledi was able to increase his GW? This is not something to be done casually. I know several manufactures that do a GW increase with floats. I would defiantly want to run it by the McBeans.

[PaulL]

Hi! I'm the Paul that Paul S. is referring to. The EW on my IO-240 powered Kitfox V was 888 before the float installation. I equipped the plane with 1700 Murphy floats and ended up with a EW = 1187. I increased the gross weight to 1705 (1550 plus 10%) after some research and conversations with Ed Downs, then owner of Kitfox. As Paul S. mentioned I had to experiment with a variety of props before I got one that was satisfactory. The prop that worked for me is a Sensenich W74EK48. I still use that prop for winter ski operation and in the summer put on a 74EK58 for better speed (about 125 mph). If you have any additional questions my email is bizpaul@comcast.net.