Prop/reduction box matching

[fred colman]

Hi Guys

My KF Mk2 has a C type gear box with a ratio of 3.47-1 on 582 grey head. Prop is a 66" 3 blade GSC .I have the chance to obtain a 68" IVO light 3 blade.Do any of you Guys run this combination (had no success with enquirys in Uk).Its not so easy to mess around with props over here, the CAA ask many questions,and may even want to do a noise test(at my expense ) so I am being cautious.If any one runs this combo.and it works well would you please let me know,it might be worth my while to bite the bullet and go ahead with change over.



Fred

[fred colman]

Hi Guys

Just in case any one else might consider this combination,when there was no feed back I contacted IVO themselves.They recomend a medium prop for 3.47:1.
To use ultralight prop I would have to change ratio to 2.62:1.Back to the GSC

[Monocock]

Fred

I am amazed that the LAA said that. I ran an IVO ground adjustable Ultralight prop on my Kitfox and the LAA were fine about it. It was a 582 with a C box and it worked an absolute treat.

I have changed aircraft now to a Mk 5 so I don't have it any more but I know for sure that the Ultralight IVO is definitely cleared for flight on Kitfoxes in the UK without having to complete a Mod4 form.

Go to the link below and have a look on page 16. My Mk 4 (G-PHYL) was cleared for a 68 inch IVO. You will see there are also a few other Kitfoxes that are cleared for the same prop too.

http://www.lightaircraftassociation....20Aircraft.pdf

Hope that helps.

[fred colman]

Hi Monocock

Thanks for reply and info.The recomendation was from IVO themselves,not the LAA.It seems 3.47:1 reduction is not used on 582 KITFOX,not in UK anyway,that is why I asked the KITFOX community on this forum.This reduction works well with 68"3 blade GSC but I want to be able to alter pitch in minutes,not hours

[Monocock]

No worries. I'm just confused now because all of the paperwork that was with my Mk 4 had the C box down as a 3.47 ratio and this was signed off by the LAA at the initial test and when I put a new blue top in last year.. Also see the fourth paragraph in the link below, as the 582's in the UK Skyrangers also have 3.47 boxes too. Maybe they have printed that wrong too, I don't know.

http://www.flylight.co.uk/skyranger/options.htm

I don't know if you have considered a Kiev prop? I know they operate well on many 582's in the UK. I recently went through a Mod 4 form process when I took the GSC off my Mk 5 (vibrated like hell due to tracking issues and GSC kindly gave me a full refund). Because the Kiev is installed on lots of other 912s engines in the UK (Foxbat, Skyranger etc) it was a simple £25 and a two page form to get it approved. The process would be the same with a 582. As I understand it, the only time a full 25 hour test procedure is required is when a prop has not been matched with an engine before.

There are lots of Kievs on 582's and they are very good value at around £700. They run ever so smoothly/quietly and setting up the pitch is a 15 minute job with the Kiev pitch tool. (I don't have shares in Kiev props, I just cannot belive the difference it has made to the aircraft!!).

I agree with you that the GSC looks nice though - I just couldn't do with the vibration I was getting right through the whole power range.

[fred colman]

Hi Guys
Took a chance and went for IVO light ,guess what,it dose not work ,pitch not coarse enough for this reduction.Never too old to learn,usualy the hard way.My error might just save someone else from making same mistake

[Av8r3400]

IVO props come in pitch ranges and I think there are two for the light, coarse and fine ranges. Maybe you got the finer pitch range? Perhaps you could exchange it for the coarse pitched one?

[fred colman]

Thanks Av8r3400 but this is a used prop,there is no going back.Cost equivalent to $575 I do believe a new one in the USA is $600 Still I would have been happy if it had worked.As you said there is 2 different pitch ranges,this one must be the finer of the two.I did ask the question but there dose not seem to be any indication marks as to which one it is.This prop performs well with 3-1 ratio so my options are,sell it on or change to 3-1.Its not the end of the world ,its great to have a Kitfox,Ill ge
t it right sooner or later

Fred

[fred colman]

Hi Guys
thought I would let you know I changed gear set to 3-1 for great result.Every thing that has been said about IVO props on Forum is 100%.
Smooth,quiet,better performance and so easy to adjust .Also changed to side rail engine mount,no vibration at all now .

Fred