Prop Choice

[Dick B in KY]

Question for the general population - How/Why did you choose the prop you have for your Kitfox? I am building a SS7 with Rotax 912ULS and am interested in the selection process folks used to get their prop - Mfg, dia, type of flying, etc.etc.

Thanks,
Dick B

[jiott]

Ditto, I am in the same boat and am very interested in the replies.

Jim

[jamesmil]

we are going to use the kive prop on our ss7.

[HighWing]

I just went through this process and took delivery recently of a Warp 68" taper tip. I am going to be flying a Model IV with the Rotax 80hp. I considered the IVO and the Kiev. A couple of guys I regularly flew with had Power Fin props and they were poor performers relative to the Warp, so didn't consider Power Fin.

I put 900 hours on a Warp with my first Model IV with no issues and the guys I most frequently flew with favored the Warp. I found while flying with some IVO guys that inflight pitch issues would occasionally occur requiring unscheduled stops to do field maintenance (two in one flight - both of the IVO equipped airplanes). The Kiev has great reports, but being fairly new, I decided to go with what I was familiar with.

Our flying group has flown all over the Western US - Parts of Washington, Oregon, Montana, Wyoming, Arizona, Utah and most of Idaho, Nevada and California. Terrain has included Mountain, high Desert and the coast.
Lowell

[DanB]

I just went through this process and took delivery recently of a Warp 68" taper tip. I am going to be flying a Model IV with the Rotax 80hp. I considered the IVO and the Kiev. A couple of guys I regularly flew with had Power Fin props and they were poor performers relative to the Warp, so didn't consider Power Fin.

I put 900 hours on a Warp with my first Model IV with no issues and the guys I most frequently flew with favored the Warp. I found while flying with some IVO guys that inflight pitch issues would occasionally occur requiring unscheduled stops to do field maintenance (two in one flight - both of the IVO equipped airplanes). The Kiev has great reports, but being fairly new, I decided to go with what I was familiar with.

Our flying group has flown all over the Western US - Parts of Washington, Oregon, Montana, Wyoming, Arizona, Utah and most of Idaho, Nevada and California. Terrain has included Mountain, high Desert and the coast.
Lowell

Thanks for posting this one Lowell. As I am somewhat of a rookie Kitfoxer having been around for only about 6 years, this is one observation I have noted as well. Many of the guys that fly with the IFA IVO Prop experience trouble (such as shorts and getting stuck in one position). This is not to say anything negative about the performance of this composite, but it is troubling to know the IFA system is not solid. Now to be fair, I have heard there are some differences in design between the light prop system and the Medium set-up. I was told at some point the Medium IVO had a "beefier" IFA designed into it but I don't know the specifics. Can someone take this and explain the differences and or, your experience? Thanks

[catz631]

I removed my Warp taper tip and installed the Kiev. It was a dramatic difference ! It is much smoother,quieter,better looking, and easy on the gearbox.I have had it for about a year and still love it. It took awhile to get the pitch correct but it is there now. My prior posts will give you more info on the selection.
This is one area where everyone has a different opinion and it kind of depends on the area of the country you are in as to which is most popular.

Jeez Lowell, I have my old Warp taper tip hanging on the wall and could have sold it to you cheap !

Dick Maddux
Fox 4,912UL
Milton,Fl

[DanB]

Thanks for posting this one Lowell. As I am somewhat of a rookie Kitfoxer having been around for only about 6 years, this is one observation I have noted as well. Many of the guys that fly with the IFA IVO Prop experience trouble (such as shorts and getting stuck in one position). This is not to say anything negative about the performance of this composite, but it is troubling to know the IFA system is not solid. Now to be fair, I have heard there are some differences in design between the light prop system and the Medium set-up. I was told at some point the Medium IVO had a "beefier" IFA designed into it but I don't know the specifics. Can someone take this and explain the differences and or, your experience? Thanks

Still waiting for someone to tell me about their experience with the IVO, IFA.
Medium vs. Light? I know there are a bunch of you out there...do I intend to start a debate about props? Yes, I think I do. Time to step up and defend the IVO IFA system. Is it lacking? Can it be better? Has anyone determined what can be done to make it more of a solid platform? Has anyone developed a fix the rest of us would be interested in?
All you ole timers...throw us youngsters a bone

[kitfox2009]

I suppose the main criteria would be whether rules that the a/c is operated under allow IFA props. If they do, then I would definitely choose IFA.
I have a Vixen (912UL) and switched to an IVO ultra light 70" about 120 hours ago. This change made my 97 mph a/c into a 117 mph a/c and allows for 1000fpm climb-outs. Pretty happy with that for 80HP!
At about 100 hours the pinion on the carrier stripped requiring replacement. I replaced this myself although I had never opened up the planetary assembly before. The job was quite a simple (about 2 hours) procedure and next time would very straight forward.
I am not sure if 100 hours is the "operating life" of these parts or whether I might have over used the IFA feature because it was a brand new fun thing to play around with. I am finding now that I probably do not play around with it much as when it was a new novelty. For example, if I am just doing circuits I now leave the prop at climb out pitch.
I just cannot understand how ANY propeller that has a fixed in flight pitch would be able to match the performance of a properly operated IFA. (Especially on these smaller horsepower engines)
I am sticking with my IVO!! Even if I need $20 parts every 100 hours!
Cheers
Don

[av8rps]

I have an 80 hp 912ul on a Kitfox IV on aerocet amphibs with a 3 blade IVO UL blade and love it. I have around 400 hours on my IVO and the only issues I've had with it was the protective leading edge tape coming loose. I'd be willing to bet that is the biggest issue most other IVO users suffer with as well. The mechanical system of the IVO UL blade is simple and reliable in my opinion. BUT, I do think there are IVO owners out there that might be having problems due to not following IVO's very specific set up and installation directions. And I think that is critical with the IVO IFA. If you don't you are likely to add additional stress to the motor and gears. Mine is set up exact to what IVO said to do, and as soon as my motor gets to the end of its travel limit my breaker pops, which I believe saves my motor and gears from being overstressed.

All that said, I unfortunately cannot tell you about the Medium blade IVO IFA as even though I have friends using the IVO medium on their Highlanders (and love the prop), they are the ground adjustable versions.

I will say if I had a 912uls rather than the 912ul I would use the medium. BUT, if any of you guys have seen the 912uls Highlander perform in the DEADSTICK TAKEOFF video (trailer is on you tube or at www.deadsticktakeoff.com ), in the video he is using a IVO IFA ultralight blade. He (Steve) says the UL "Patriot" blade works ok on the 100 hp 912, but it does cavitate a bit on initial power application. But hey, if you watch the video you will see one super performing back country airplane doing some pretty wild things that many wouldn't even think possible. So the IVO UL IFA must still work pretty well, even on the 100 hp engine.

I will post in a separate reply info I did on another forum recently where I shared specific performance numbers from my IVO compared to a ground adjustable version. In that I give some pretty hard numbers, along with some pretty upfront and honest opinions about the IVO. Maybe that will help answer more of your questions.

[av8rps]

And here's some IVO IFA info I had posted on another forum that you may find interesting;

Last night while flying my Kitfox amphib in really nice calm skies I did a test to see what the real gain is for top speed using my IVO in flight adjustable prop verses if it were a ground adjustable version (to do the comparison I just moved the prop switch to change the pitch, "pretending" as if I had adjusted the prop on the ground with a wrench and a prop angle gauge).

Here are my results;

Flying straight and level with wide open throttle (912ul - all 81 ponies)

- At 5800 max rpm I was able to go 119 mph.

- Leaving the prop set for a max rpm of 5800, I pulled the throttle back to 5500 rpm (max continuous power for a 912) and my top speed was now 114 mph.

- Putting the throttle back to wide open again, I increased the pitch so I could only get 5500 rpm, which provided the highest speed tested...124 mph.

- Moving the electric prop to maximum pitch while keeping the throttle still wide open, giving me 5275 rpm my top speed dropped to 116 mph.

So, I proved to myself last night that the inflight adjustable prop does in fact make my Kitfox faster. BUT, if I set a ground adjustable version to a max of 5500 rpm, it would fly just as fast (assuming the blade style and dimensions were the same for both props). Of course, then I would lose some takeoff and climb performance, so a better setting for water ops or STOL work might be a max rpm setting of 5800 rpm straight and level. So I could expect to lose around 10 mph in top speed when comparing the IFA to a ground adjust version.

In addition to the improved top speed, takeoff, and climb, another thing I really like to do with mine is to fly around at 4,000 rpm at 80-85 mph with a lot of pitch. It makes for a really quiet and smooth pleasure flight that doesn't burn much fuel.

So for now, I'll be keeping my IFA prop. I shared this information so I could let everyone know what the real gains are with an IFA prop.