Cost of Five-Year Rubber Replacement

[Peteohms]

Will,

Hi neighbor. I live N of Austin.

My Kitfox III was built in 1991 and has an older 912. I have 1100 hrs on the engine. I believe most of the Service Bulletins have been complied with. I was a Kitfox novice when I flew it home 400 miles in 2008.

By law, you don't need to comply with the 5 year rubber replacement. That being said, I got a fresh condition inspection by Murle Williams before I flew it home. Then what I did is start replacing my rubber over time after I got the plane. The Rotax people will tell you that you need to rebuild the engine just because of age. I chose not to rebuild. I took a couple Rotax 912 classes a few years ago, but I have always maintained my Kitfox and 912.

I'd hate to make a judgement on the price as there are a lot of factors. My engine is still running strong, but paint is cracking and blistering because of auto paint over aircraft finish. Be happy to answer more questions. Leave me a private message here with your number and we can chat.

[Peteohms]

My Kitfox had at least 4 owners before me. It had only 325 hrs with all those owners over 17 years. I've flown 775 hours with only an occasional item to repair. I'd advise trying to find an owner in the area where you pick up the plane.

[kitfox2009]

Hi guys
My Vixen was completed in 1999 and flew just over 100 hours prior to my purchase in 2009. It now has almost 600 hours,912 UL with IVO IFA prop.
I replace hoses by taking the metal nipple parts to my local auto parts store and going into the parts room and physically matching up "formed" hoses, both with correct inside diameters and bends and elbows that match the engine shapes.
Many replacement hoses on late model vehicles can be cut up to do a nice job.
I realize these are not aviation grade but so far it has worked well. Fifty dollars buys quite a few hose pieces.
Don

[Slyfox]

My thoughts are to tell the guy the engine is out of TBO hours. then get the price as low as possible, like 20K. buy the plane and then get a new motor, and engine mount and put it together. now you have an airplane. good luck

[HighWing]

The routine replacement of the rubber components every five years has always mystified me. I put nine years on my first IV and only replaced two perfectly good carburetor diaphragms in that time.

Back in the day, I did participate in the "Mandatory" Service Letter requiring the replacement of the stator. Then I found out that the replacement was triggered by the engine compartment in certified versions in certain training aircraft being regularly hosed down with solvents. This caused a collapse of the (Non Aviation Grade) insulation on the wire used by the manufacturer of the stator. This was under undersized Adel style clamps. It wouldn't surprise me at all if this recommended (Required - depending on who you are listening to) 5 year replacement had been triggered by similar engine treatment or mistreatment. I have mentioned this before, but when I was training for a long delayed Biannual Flight Review in a rented Citabria, the pre-flight check list said, "...open the cowl door and check engine oil level and check for any loose or frayed wires. Yea Right, looking in that dark compartment through a 6"X6" hole. My guess is if you are never going to pop the hood until your annual, it is very likely a good idea.

I went online and did a search of "Rotax 5 year" and got the following link. The article is from Rotax. Sorry for this old guy's cynicism, but the arguments presented sound very similar to the ones I got last evening on a "cold call" that recommended I get the wireless security system the caller offered for "FREE". lots of "others are doing" "wife and family", "peace of mind" with absolutely no specifics. It would have been very persuasive if when mentioning "Other engine manufacturers following Rotax's lead" he would have mentioned at least one such manufacturer.

http://www.rotax-owner.com/en/rotax-...er-replacement

Then I read the comments section and found this which says it exactly as I feel about it.

Maybe.pdf

Without a doubt this is a decision that each pilot / owner should consider and the phrase, "To Each his Own" is the only mandatory action, in my opinion.

[HighWing]

I just got back from visiting a friend and neighbor who has a Model IV he built. The AWC is dated 1997 and the current engine install was dated 2000 - 912 ULS. My intent on the visit was to ask him about his view on the 5 year thing. I respect his opinion largely because of his training and work in aerospace engineering along with his experience as a long time owner builder. I mentioned the $7000 figure and he laughed out loud. I then quizzed him on his experience. I asked about his hours - 1900 total Hobbs hours. I then asked him in the 1900 how many times he has replaced the rubber. He laughed again and said "probably half", meaning an equivalent half the rubber replaced in the 1900 hours. Then he explained; He used to replace one of the 1" coolant hoses to the radiator every year because of its close proximity to an exhaust pipe. He then lengthened that interval to two years. He replaced the spider hoses from the tank once because he felt being on top of the engine they likely were exposed to more heat than other hoses. That's it on rubber. He also did the stator replacement, but added that he wouldn't do it today due to an increased understanding of the original situation.

Please consider this post as just food for thought.

[Dave S]

Lowell,

Good points.....I'll probably challenge the term "old guys cynicism" and replace it with "Good judgement tempered by experience and enhanced by cronological superiority"

You know, when I indicated my guestimate on cost of the 5 year plan, I didn't offer any opinion on the validity of the 5 year shotgun approach.

So I did replace stuff......and my experience caused me to question that I may have replaced many expensive and perfectly good parts.

Most fuel hoses and coolant hoses are not particularily expensive so that doesn't bother me much anyway (except for the 17mm ones Rotax is quite proud of).

The Carburetor flanges....frankly I could not tell the difference between the old and new except for the distinct odor of Auto Fuel on the old ones and some numbers imprinted in the rubber. Took the clamps off, bent, folded, twisted the rubber and could not find the slightest inkling of any degredation, wear, cracking. Both old an new showed no surface ozidation of the rubber or any separation from the substructure. Both the old and new ones were the ones with the spacer on the clamp to guarantee the correct tension on the clamp. It is my understanding that some earlier ones did not have the spacer and could be overtightened damaging the rubber flange. I happen to have the airbox installed, which probably helps durability compared to a free ended carb in the socket - with the airbox, I can't even wiggle a carb.

The carb diaphrams...same deal......old ones smelled like autogas but otherwise appeared good as new...no cracks or start of cracks, no reduction in flexibility at all compared to the new ones.

When I replaced the fuel hoses...not just the engine side but the whole works, I could find no problems with them either, but they were pretty inexpensive anyway. On the other hand, I have replaced the stub fuel hoses that hook to the fuel filter at less than 5 years as they get some addittional wear and tear from changing filters. I also do a fuel flow test of the whole system at condition inspection and compare the flow rate to see if there has been any reduction in flow which could happen if a hose swells internally - always been fine.

I happen to have the aux belt driven alternator....I did not replace the belt which is indicated in the Rotax 5 Year plan.....realize not many have this option; but, since I have two alternators and a cross tie/isolation system, and fly VFR...I hardly think the alternator belt which is observed to be in good condition is any risk to my health and wellfare.

Here's the deal.....I have seen certificated aircraft with really, really ancient rubber parts still in use...like tank connectors, alternator belts on single alternator aircraft...can't help but feel that we are in much better shape with our experimentals where we actually know what is going on with the actual condition of the parts.

Maybe I mentioned it before; but, Rotax is only concerned with Rotax parts.....we're concerned about the entire system from fuel cap on the wing tank (Like the cap seal) to the exhaust port. There is no 5 year plan for the non rotax parts. A case could be made that our judgment as experimental operators applies to both.

So do I think I replaced perfectly good parts?...the answer to that is probably yes.

Dave S
KF 7 Trigear
912ULS Warp Drive

[Dorsal]

Having just replaced all the coolant lines from an engine that is 15 years old (but only the last 5 in use), I believe the failure mode of these lines is most likely what I experienced which is a few mildly annoying leaks. It is a bit hard for me to imagine going from a tight system to a catastrophic flight threatening failure. The lines I removed were clearly not as supple as the new ones and all the leaks went away. I am unlikely to replace these until I have the same or similar problem which I expect will be well more than 5 years.

[napierm]

I did a rubber replacement on my 1997 rotax. Even though it only had ~200 it was the right thing to do. Many of the hoses felt fine from the outside but were extremely thin under the clamps. I bought everything I could 2nd source. Rotax is very proud of their parts.

[Peteohms]

The Rotax splitter fuel hose is something like $400. I replaced all of my oil lines, fuel lines, and water lines, some are NAPA, the water lines going into the top of the heads, and going out the bottom of the heads I got from Lockwood. I added some fire sleave , an I doubt I spent $600 on the hoses. I sent my carbs to Lockwood to get rebuilt $400 for both. so I have right at $1000 in to the 5 year rubber change. I'm doing my own work on my SLSA, about 8 hours labor. If I charged $100 per hour the total bill would be about $1800. I am a LSRM.

What did you use for oil hoses Paul?