Sport Pilot Talk

Fairly solid on my choice of the Excalibur 2 seat. Mix of proven design, price, STOL and interchangeability with amphib floats suits my needs. I get hung up on the engine though. I want a 4 stroke or diesel. Here's what I've got so far:

1. HKS700e: 4 stroke but slightly underpowered IMO for a 2 seater with floats. Also company backing is sketchy (already removed turbo version from US market) and TBO is still low compared to competitors. Overhaul costs and fuel efficiency is far superior though.
2. Aerovee 2.1: build yourself so I'd be able to perform maintenance. Works on pump gas. Anecdotal evidence says it's not as powerful as the rating suggests. Would require custom mounting.
3. VW 0.8L Diesel: daydreaming here...this is from the new XL1 hybrid (http://www.greencarcongress.com/2013/02 ... 30221.html). Only 47 hp but 74 ft lbs and at 1900 rpm which would be perfect...no reduction drive. Not sure how much it weighs, but it's an aluminum block. Lots more research required (mounting, fuel management, etc) but running diesel or JetA has its perks!

Thoughts/alternatives?

No Rotax option?

They don't offer a 4 stroke in my size/power/price category...that I know of. The 912 is too much engine and way too Pricey. Also cost of ownership is much higher than the HKS. I'm a tad annoyed with the cost of airplane engines in general...doesn't me I won't consider them though.

I'm confused. You say the VW diesel is "only" 47 HP, which suggests you consider that on the low side. But you say the 912, which comes in an 80 HP iteration, is "too much engine." So, splitting the difference , your target is what, 65 HP or so? That sounds like Continental territory to me (Cubs and Champs ran on the C65 for decades.)

I have heard various reliability gripes about the HKS engines. Just rumor, but it's out there.

The VW conversions are heavy and sometimes finicky. I was building a Sonex and got a lot of exposure to the Aerovee VW conversions. Since they come as a kit and are built by the owner, the quality and reliability of the engines varies wildly. As a rule, the guys with Aerovee-powered Sonex airplanes seem to spend a lot more time "fiddling" with the engine to get it running right than guys that stepped up to the Jabiru 3300.

And the weight... 161lb dry for an Aerovee to get 76hp is just plain heavy. A buddy of mine has a VW-powered Kitfox and it's a dog. Part of the reason is that the RPM range of the engine is such that you can only sling a very short prop before you get into transonic prop tip drag that kills performance. You can add a gear reduction unit to the engine to spin a larger prop, but now you are adding 15-30lb to an already heavy engine...

If it were me, I'd be scouring barnstormers for a used, well running 80hp Rotax 912UL. An Aerovee kit costs about $7k, I bet you can get the Rotax for not much more than that, and a get a couple more hp, save 30lb, and get a more reliable engine in the process.

Concur.
Excellent advice Andy.

The 912 Rotax motors are amazing. I've heard that the 80 HP is even more reliable as it is not pushing the limits as much.

The main advantage of the 80 HP 912UL, as opposed to the 100 HP 912ULS, is that its low compression heads allow you to use regular 87UL unleaded auto fuel, as opposed to 91UL or 100LL. Though Rotax allows up to 10% ethanol, many airframes are incompatible with it, so check carefully. Better still, just use ethanol-free mogas if it's available in your area.

Or for $2500 more than the Aervoee, get a mid-time 100hp Rotax 912ULS!

http://www.barnstormers.com/classified_ ... ngine.html

THAT is a deal.

Overhaul cost of the 912 is nuts (IMHO). The appeal of the Aerovee is the ability to do any work myself and set my own TBO. Also, 47 hp is low, but the torque with diesels makes up for it, not to mention epic fuel efficiency and durability. Not sure if the 912 would be too much power for the Excalibur frame. I'm assuming there's a reason they only offer the 503 and 582.

With its 2000 hour TBO and outstanding reliability (many have made 3000 hours without ever having the heads off), overhaul costs of the 912 become almost irrelevant for the private owner. As for power being "too much" for an airframe, weight is the main limitation, not power. You can always increase prop pitch to limit RPM and keep power wherever you want it.

That said, any engine that keeps you flying is a good engine.

I did not have any reliability issues with HKS 700E thus far (coming on about 200 hours). However a 2-seater with it must be something like Quicksilver, else it's pure fantasy. People who bring up a 65 hp Cub conveniently forget how small people were back then. I weigh 230 lbs and I'm quite skinny. And HKS 700E is rated for 56 hp continuous, with 60 hp for takeoff only, which is quite a bit less.

One thing about HKS that I don't like is that the stock ignition scheme relies on bus power. If you want an aviation type separate power for the ignition, you have to engineer your own.

If I wanted a 2-seat airplane, I would have to pay for Rotax or even a small ULpower (260i). I could consider AeroVee turbo if they ever put it on the market (after the death of Jeremy Monnett).

zaitcev wrote: If I wanted a 2-seat airplane, I would have to pay for Rotax or even a small ULpower (260i). I could consider AeroVee turbo if they ever put it on the market (after the death of Jeremy Monnett).

There are several Sonex flying with the Aerovee turbo. It can be bought here, cost is $10,999:

http://www.sonexaircraft.com/eshop/cart ... ory_id=329

MrMorden wrote:

zaitcev wrote: If I wanted a 2-seat airplane, I would have to pay for Rotax or even a small ULpower (260i). I could consider AeroVee turbo if they ever put it on the market (after the death of Jeremy Monnett).

There are several Sonex flying with the Aerovee turbo. It can be bought here, cost is $10,999:

http://www.sonexaircraft.com/eshop/cart ... ory_id=329

Like it, but again may be more engine than I need. Just looking to be able to get off the water with 2 people. Beyond that I want fuel efficiency (for distance, not cost) and reliability. Guessing the turbo is less reliable than the non. I'll look into a "gently used" 912.

MrMorden wrote:

zaitcev wrote: If I wanted a 2-seat airplane, I would have to pay for Rotax or even a small ULpower (260i). I could consider AeroVee turbo if they ever put it on the market (after the death of Jeremy Monnett).

There are several Sonex flying with the Aerovee turbo. It can be bought here, cost is $10,999:

http://www.sonexaircraft.com/eshop/cart ... ory_id=329

Like it, but again may be more engine than I need. Just looking to be able to get off the water with 2 people. Beyond that I want fuel efficiency (for distance, not cost) and reliability. Guessing the turbo is less reliable than the non. I'll look into a "gently used" 912.