IVO Light vs Med - Kitfox Speedster

[Monocock]

Another Kiev disciple!
I know I harp on about the merits of Kiev props but everyone I have met who flys behind one agrees - what they do to an aircraft's performance is quite incredible and they are one of the cheapest out there too.

[jdmcbean]

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. James Thomas

Be careful... The speed limit on a road is 35 and if going 45 and get caught you get a ticket... If you don't get caught.. then it didn't matter. In aviation it will most likely only matter with Insurance... very rarely a ramp check (but it does happen) On the other hand we need to stop calling the prop In-Flight Adjustable and rename them to something like Electric Adjustable Pitch It does say ground adjust not that it has to be manual.

The rule FAR 1.1: emphasis on the first line (ORIGINAL CERTIFICATION, has CONTINUED TO MEET the following_

Light-sport aircraft means an aircraft, other than a helicopter or powered-lift that, since its original certification, has continued to meet the following:
(1) A maximum takeoff weight of not more than--
(i) 1,320 pounds (600 kilograms) for aircraft not intended for operation on water; or
(ii) 1,430 pounds (650 kilograms) for an aircraft intended for operation on water.
(2) A maximum airspeed in level flight with maximum continuous power (VH) of not more than 120 knots CAS under standard atmospheric conditions at sea level.
(3) A maximum never-exceed speed (VNE) of not more than 120 knots CAS for a glider.
(4) A maximum stalling speed or minimum steady flight speed without the use of lift-enhancing devices (VS1) of not more than 45 knots CAS at the aircraft's maximum certificated takeoff weight and most critical center of gravity.
(5) A maximum seating capacity of no more than two persons, including the pilot.
(6) A single, reciprocating engine, if powered.
(7) A fixed or ground-adjustable propeller if a powered aircraft other than a powered glider.
(8) A fixed or autofeathering propeller system if a powered glider.
(9) A fixed-pitch, semi-rigid, teetering, two-blade rotor system, if a gyroplane.
(10) A nonpressurized cabin, if equipped with a cabin.
(11) Fixed landing gear, except for an aircraft intended for operation on water or a glider.
(12) Fixed or retractable landing gear, or a hull, for an aircraft intended for operation on water.
(13) Fixed or retractable landing gear for a glider.

Regarding CubCrafters Carbon Cub with a 180hp.. I could be corrected on the speed.. but I doubt a Cub can be pushed to 120 kts even with 180 hp... The ASTM rule comes into play. This is not true on the Experimental Amatuer Built aircraft... but an S-LSA must meet a minimum useful load requirement and the formula is based on continuous HP and number of seats. So CubCrafters restricts THEIR engine RPM to continuous operation of 80hp and you can use the max hp for up to 5 minutes (Rotax 912- 5500 continuous 5800 max 5 minutes) using the formula at 80 hp the Cub must have a minimum useful of 433lbs (887 Empty) and at the 180 hp 501lbs (819 Empty)..

Now.. how about the CC340 on a Kitfox

[DBVZ]

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?

The continuous requirement would mean that if an otherwise eligible LSA were to ever have an IFA prop on it, even briefly, it is permanently ineligible to be flown under Sport Pilot rules. Kind of a big decision, if you have an eligible LSA and may some day want to go Sport Pilot. Everyone gets older. It also limits resale opportunities.

[herman pahls]

I have 450 hours behind a Rotax 532 and ground adj.Ivo light prop on my model 2. Great results.
I am considering going with a 582 and called Ivo as to what C-box ratio and Ivo prop would get the best short field performance.
They suggested the 3.47 C-box and Ivo medium.
What gearbox ratios do the 912's use that they can use the ultralight Ivo's?
Has anyone used the in flight adj. Ivo's on a 532/582 and what were the results?
Thanks Herman

[N82HB]

I had a two blade IFA Ivo on a 582 with C-box. It was not ideal, but had some benefits. It is very important to take the time to set up the washers for the fine and coarse stops to make it easier to use while in flight.
Here is the part to watch out for:
With a two stroke where mixture is so important you need to learn about "effective jetting." As you go fine on the pitch your engine goes lean and then coarse makes the engine go rich, for any given RPM. It is just one more way we have found to make a 2-stroke burn up that much faster. You can make it work, but it is pretty risky and quite a bit of work to get set up right.
Kelly

[herman pahls]

Kelly
Thanks for your imput regarding in flight adj. and 2 strokes.
Sounds like a mixture control would ideally be needed.
I prefer not to use the Ivo medium prop due to added weight and cost.
What C-box ratios are being used on 582's and Ivo light props for best climb performance?
Thanks Herman

[akflyer]

I have 450 hours behind a Rotax 532 and ground adj.Ivo light prop on my model 2. Great results.

I run a 3 blade 72" IVO IFA on my 582 with 3:1 gears. I had 2.62 originally, and even though IVO says that it is not suggested, I have not had any issues running the 3:1. I have the tape over the blade roots so I can see if there is any movement and in 200 hrs, I have not cracked a tape.

I love the IFA and would not give it up for anything! Jet per the charts and you can use the IFA to keep your EGTS exactly where you want them. More pitch, EGT's go down, less pitch they go up. I also have inflight mixture control, but I think I may get rid of that as you can tweak and turn and doink with them all day instead of enjoying your flight! The only time I found them really useful is in the winter time when I take off from a river or lake bed and it is -25f or -30f and at 1000' it is 20f above. Then it is important to be able to control the mixture and riched it up down low. I never fly high enough up here to warrant the mixture control 98% of the time!

[akflyer]

The continuous requirement would mean that if an otherwise eligible LSA were to ever have an IFA prop on it, even briefly, it is permanently ineligible to be flown under Sport Pilot rules. Kind of a big decision, if you have an eligible LSA and may some day want to go Sport Pilot. Everyone gets older. It also limits resale opportunities.

No need to mention the prop on the plane... you can just put in the log book that it has an IVO ground adjust if you are worried about sport pilot. Most times you will find that it is better not offer up any info you are not directly asked when it come to dealing with the authorities.

[Av8r_Sed]

Herman,

I've got a Model III 582 with a 3:1 C gearbox. I've been advised by IVO and the factory to go with the medium 70" IVO two blade. I haven't flown this configuration yet but hope to soon.

-- Paul S

[DBVZ]

No need to mention the prop on the plane....

Now we are into falsification of records if it actually has a IFA prop. Someone earlier suggested calling the IFA an "electric adjustable" prop instead of in-flight, and then the issue of ground adjust or in-flight becomes a question of where the control is located. Under cowl would make it ground adjust, and in the cabin it would be in-flight. But I asked that of an aircraft MFG rep, and he said that had been tried and rejected by the FAA. Not Kitfox, but the same FAA. If your records are accurate and complete, if it had an IFA prop on it the logs will indicate that by explicit statement or by the model number of the installed parts. And if it ever had an IFA prop it is FOREVER not Sport Pilot eligible. Stupid rule, but that is what they say. Same issue about 2 seats. The Avid Catalina is 600 empty, 1200 gross, but usually has a third seat in back. If it was ever operated as a 3-seat plane it is not eligible for Sport Pilot. But if it was not operated as a 3-seat, and the rear space is marked "baggage area, weight limit 200 pounds", my understanding is that it would be Sport Pilot legal. The "continuously maintained" part of the regulation just limits the number of legal LSA aircraft for no purpose. If it is currently configured to conform, what difference does it make that it was not a few years ago?

And my point was, if you ever think you may want to fly it as a Sport Pilot, think about that before you put an IFA prop on it or you may need to replace the plane sometime in the future. If you don't care about Sport Pilot, and don't care about the loss of some potential buyers in the future, then go for the IFA prop and be done. It should give you better control of performance. For a young healthy owner, the issue may be decades away and easy to ignore. But some of us are not that young anymore. And it may be worth thinking about this more now, and regretting less later.