Kiev prop moment of inertia

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Kiev prop moment of inertia

Postby preacoupe » Tue Jul 02, 2013 5:41 pm

Hi everyone,

Well, I've reached a point that I never thought would come. 99.9% done! But, do have a few loose ends before Airworthiness Inspection and first flight.

Apparently, for warranty reasons Rotax wants from me what prop I'm using (Kiev #293) and its Moment of Inertia. I have a couple of pages of instructions on how to calculate this, but involves jumping through some hoops. Just thought if some of you had the Rotax 912/Kiev combo, then you might have the data that you sent to Rotax handy. Wrote Kiev people, but they didn't have the info for the 293 (74.8" diameter). They had some numbers for a 70.9" model from some years ago. The 293 is supposed to be light, so all should be OK and it should come in under Rotax's 6000kgcm (squared) max.

Dennis
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Re: Kiev prop moment of inertia

Postby stede52 » Tue Jul 02, 2013 8:26 pm

The 293 has been put on Highlander rotax engines for a long time. I wouldn't worry about the numbers, just use it. Call Troy, he's been running the 74" for years and has tested more props then you can imagine and he always goes back to the Kiev 74". I also used that prop on my first highlander and I worked great for me and I think Steve H has gone back to it also, but I'm not 100% sure. I know he's running the a kiev again.
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Re: Kiev prop moment of inertia (MMOI)

Postby jjacky » Wed Sep 09, 2015 12:02 pm

Hey stede ..it time to register the Rotax with a Kiev 293 and I cant find the prop's MMOI anywhere...did you ever get a clear answer on this?
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Re: Kiev prop moment of inertia

Postby stede52 » Thu Sep 10, 2015 11:06 am

jjacky, sorry if I did its been way too ago :( , maybe someone else can answer your question
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Re: Kiev prop moment of inertia

Postby preacoupe » Sat Sep 12, 2015 11:19 am

Hi guys,

I sent the question to Ronnie Smith (Rotax guy) and didn't receive an answer. That was 2 years ago. But Steve is right, Troy and so many have used the combination for so long, that I'm sure it is not a problem. I just have installed mine with no adverse effects. Of course, I'm only 120 hrs on the engine....

Dennis
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Re: Kiev prop moment of inertia

Postby Jack L » Sun Sep 13, 2015 7:15 am

Guys this is what I got from Kiev Ukraine:

Kievprop <[email protected]>
12/15/14
to me

Dear Jack,

The mass moment of inertia of the prop 293 fluctuate in the range between 4800 - 5000 kg*cm²

Best regards,

Sergey.
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Re: Kiev prop moment of inertia

Postby jjacky » Mon Sep 14, 2015 4:28 pm

Great and thanks all. Margie and I performed the MMOI measurement on the Kiev 293 prop (SN:293276) this weekend. We did it in accordance with Rotax Service Information SI 11 UL 91E. Since she can count better than I can she swung the prop and counted 30 cycles and I timed it. We did it three times and got 167 seconds every time (maybe if I had a stop watch that displayed tenths of second we may have seen some variation but the repeatability was remarkable) The prop, hub, spinner, extender and all bolts and nuts together weighed 5024 grams. Margie did the graph with her parts per million eyeballs and came up with: 4780 kg*cm^2. So...4800 it is. Thanks again for your help.
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Re: Kiev prop moment of inertia

Postby preacoupe » Tue Sep 15, 2015 11:36 am

Jack,

Thanks so much for posting your work. I was just too lazy to go through all of that. I'm sure this is invaluable to many in the same boat.

Dennis
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