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ColdFusion
01-31-2021, 11:03 AM
What am i missing... engine question


I am shopping engines...


As much as the Yamaha edge is dominating the news in endless YouTubes right now, I am more comfortable with a traditional approach to engine reliability - I do not need 300 HP, don’t want the noise, the associated internal stresses and all the problems associated with living at the limits.


My primary focus is reliability and I willing to give up performance and pay extra for that.


Right now I am looking at the Titon 340, Rotax 915is and the Viking Honda 170HP (turbo) at half the price, but used... I know nothing about the Viking conversion but I do know I have owned many honda cars and even a 250 HP marine engine with zero problems - ever.


In regards to aircraft, I am still on the fence. With the Kitfox delivery so far out I have fully shifted focus to the Highlander, S-21, and even the Zeneth 750. The nose wheel is a concern but with that said , cub crafters indicates better stol numbers with their nose wheel models. My biggest concern with the Zenith is the nose wheel getting in the way in rougher areas. Right now I’m about 70% S-21, 10% Highlander and 20% Zenith. Folding wing has zero appeal, as it will be hangared. Primary use will be low level solo flight in southern Utah. I absolutely will not be cruising at 12,000 unless in ground effect.


The general stats...


Viking / 170 Turbo Honda at about $20k
This engine is direct inject at 260 lbs with gear box
Advantages - price, reliability, direct inject, turbo, performance.
Disadvantage - weight


Titan 340 / 160 HP at about $30k
Fuel injection no turbo at 245 lbs with direct drive
Advantages - reputation of builder, direct drive (lower rpm), higher tbo
Disadvantages - weight, not turbo


Rotax 915is 135 HP at about $40k (the 140HP is a 5 minute burst rating)
Fuel injection with turbo at 185 pounds with gear box (1200 tbo)
Advantages - low weight, turbo
Disadvantages - cost, low tbo, lowest HP


I like all three.


Is the direct drive enough of a benefit to focus on Titan.


Is the weight saving enough to focus on Rotax even with 1200 tbo.


Is the extra weight of the Viking offset by the higher HP and lower cost.


If all three engines were FREE and cost was not a driver, which one would you pick and why.


I am not worried about the Viking being a used engine as it is a Honda, and with 30 years of owning a Honda’s, the reliability is very high.




I’m thinking the Viking... what am I missing...


Would you go to the Titan fuel inject 360 or 370 at 180HP at 280 pounds...

SomeDay7
01-31-2021, 11:17 AM
How about insuring. Which is the most costly to insure? Kitfox factory pushes for the rotax. My build will be what the factory is saying. First build. They set this up for me with a kit. I like what they are saying. Built a kit car. Didn't deviate much from what they were saying. Got it done in quickly.

Danzer1
01-31-2021, 04:27 PM
Out of those three, I'd go Titan if you want tried and true reliability. Can easily get to 180 hp. 915 to complex and expensive to buy and maintain. Viking is used rebuilt engines and Viking owner has a very bad previous company record - I wouldn't go near it - do a lot more research on that one.

BTW, the S-21 is over a year out now too but pretty darned fast to build!

YMMV, Cheers

Maverick
01-31-2021, 05:04 PM
Yes, insuring is very much a concern. An experimental engine in an experimental airplane is going to cost you on the insurance side of the equation if you can even get it insured. Check out this video: https://www.youtube.com/watch?v=cVNqmE33NTU

The discussion is about 45 minutes but the parts you might be most interested in hearing starts at about minute 19 and about engines in experimentals is around minute 22. The number of airplanes built and flown impacts the insurance cost a great deal. An RV7 (6,8,9,14) will get you a better rate than a Mustang II that will fly as fast and as well. The sheer volume of RVs in the actuarials helps with the rates. That is an advantage to the Kitfox. There are quite a few out there flying with Rotax engines and this quiets down the heartburn the insurance carriers have over experimentals. But, throw anything other than a Rotax, Lycoming, or Continental on it and you just upped you insurance rates. And, your age is going to really zing you so, you want to keep other factors limited as much as you can.

Also, don't forget about support. The Rotax aircraft engine has been around for somewhere around thirty years so the collective experiential knowledge of owners and mechanics far exceeds that of the other engines in vogue right now.

Here's a good video that talks about the Yamaha and Rotax engines that might be of interest for you: https://www.youtube.com/watch?v=qqH0hToo9TM

Av8r3400
01-31-2021, 07:47 PM
I won't fly an auto conversion. Ever. Especially something from Jan Eggenfellner. Factor in the insurance issues and game over...

The weight penalty of the Titan will kill any power advantage it may offer. Combine the weight of the engine and the high fuel burn (more fuel weight) any you'll wind up with 300-400#useful load at a non-LSA 1550 MTOW.

Why the 915? Why not a 912 ULS for half the cost? Or if you need more HP the Edge performance injected big bore for 125-135 hp without the weight, heat, complexity and cost of a turbo.


This is a Kitfox board so I won't bash the S21. It's a fine plane...

GuppyWN
02-02-2021, 09:55 AM
I won't fly an auto conversion. Ever. Especially something from Jan Eggenfellner. Factor in the insurance issues and game over...

The weight penalty of the Titan will kill any power advantage it may offer. Combine the weight of the engine and the high fuel burn (more fuel weight) any you'll wind up with 300-400#useful load at a non-LSA 1550 MTOW.

Why the 915? Why not a 912 ULS for half the cost? Or if you need more HP the Edge performance injected big bore for 125-135 hp without the weight, heat, complexity and cost of a turbo.


This is a Kitfox board so I won't bash the S21. It's a fine plane...

Exactly.

I too was going to ask about the need of a 915. I fly my 912 in the mountains. Sure, I'd like more power but it's not required.