IVO Light vs Med - Kitfox Speedster

[Monocock]

Kitfox2009,

I agree, a ground adjustable prop on the whole will be no where near as efficient as an IFA one. However, there is a large variation in the efficiency of different ground adjustable props. I went from a GSC to a Kiev and I was utterly amazed at the difference. The GSC didn't run that smoothly, was noisy and performed around 20% worse in the climb and cruise. It seemed rigid and unforgiving.

I would strongly urge anybody who is considering an IFA to try a Kiev 263 before they spend their money. The smoothness is incredible and you will be amazed at the acceleration!!!!!!!!!

[Dorsal]

It is true that you can't have a fixed pitch prop optimized for both cruise and climb. In my case I have set the pitch for best cruise and therefore sacrifice takeoff and climb performance. You could also make the case that even in cruise an IFA prop could be tuned for altitude but I am not sure how much effect that would have.

[Slyfox]

i could not imagine flying with out my ifa. I love taking off and passing the cessna on the other runway. That's matching his altitude and such. I start off with flat pitch and bump the switch a little and maintain 5800 and climb out and slowly reduce rpm with prop adjustment to 5200 and pretty much pass the cessnas, a real hoot. don't go with what I can do for a max climb out it really bothers people.

[Dorsal]

That sounds like fun, given what I can do at 5200 rpm I often wonder how much fun it would be if I could actually use full power on takeoff

[jhmcglynn]

Hi All, this question may come under the heading of "it's easier to beg forgiveness than ask permission" but here goes. I guess "IFA" stands for In Flight Adjustable. Regarding LSA - is there any rules that will allow you to put an IFA on your Kitfox and stay within the LSA category?

[Slyfox]

ya, put the switch under the cowl, you can at least change it on a whim without pulling out the wrenches. You can't be flying unless your good at wing walking

[Av8r3400]

Placard the switch: "Ground Adjust Only"


Problem solved.

[jrthomas]

In response to Av8r3400, one word, "brilliant"! If we can placecard maximum cruise rpm to prevent a light sport aircraft from exceeding 138mph why not placecard an IFA prop switch "Ground adjust only". Cub Crafters pulled it off and leaves up to the pilot to limit cruise power to 80hp out of a 180hp engine. If that will flush with the FAA then Av8r's idea should be a breeze. James Thomas

[Squirrelfox]

Regarding Brilliant....Can't help responding.

Let's take the placarding a step further:

"SS7 Take off weight limited to 1320 pounds while operating as LSA; else 1550 pounds with gear upgrade"

Problem solved, opens up the options

Now don't you think the FAA will cooperate?

[jrthomas]

I know it's silly. It seems at first to be a violation to put an IFA prop switch in reach of the pilot but Cub Crafters pulled off putting 180hp within the pilots reach and leaving it to the honor system that the pilot won't ever use it to exceed max cruise limits. All this in a 900lb+ airplane with a 400lb load limit that the FAA trusts the pilot not to exceed. Cub Crafters makes it all legal with placecards. My agreement with Av8r was, just for the sake of discussion. If it works for Cub Crafters, why not Kitfox? To be realistic, DAR's see things differently. Some follow the letter of the manual and some interprete. There may be some DAR's that would let it slide. Anyway, I just jumped in the conversation as "Food for thought" ,"what if". I have a Speedster With a Kiev and have no desire for a IFA prop. James Thomas