Shoptalkforums.com

I'm starting to plan for an aircraft build and I'm wondering what the best type 4 build combo would be for operating range between 3000-4000rpm and a goal of 100hp peak takeoff power and 75% continuous power around 3300-3500 or so?

Greatplainsas.com sells a T4 kit with 71 stroke 103 bore (2400cc)

I would think that for a low RPM aircraft motor you would want max stroke for more torque. The one I'm planning to build is a shoft takeoff bush plane (big slow prop). I know on Jakes webpage he says theres no need for 103mm, the same power can be had with smaller displacements and the proper combo, and some people have said 103's are prone to cooling problems.

What are your thoughts on a 84mm stroke and stock 94 bore?
I'd like to use stock 2.0 3 bolt intake heads if possible.

Lets hear some ideas and opinions

Have you contacted the EAA about this? They would most likely have files on airplanes that have been built, ones like you are talking about and may even have contacts you could use. They would also have the requirements that you would have to meet also. Several of the guys I worked with (Jan '72 to July '76 so my knowledge and memory is limited to that time) were building their own airplanes and I remember that they had a bunch of limitations, inspections and the like that they had to meet.

Lee

You can check out http://www.revmasteraviation.com/ Type 1 stuff

Or here http://www.vw-engines.com/products.htm & http://www.vw-engines.com/RG2000.htm Type lV with some interesting Bore & Stroke options.

The prices and other things for sale does sound like aircraft. Couldn't open the VW-engines.com URL as it was blocked by my security as being a bad site for some reason.

Lee

You'll never cruise much above 2850. What prop will you be using? Remember tip speed. Once the tip speed goes supersonic you'll lose your "bite" in the air.

Stroking a T4 motor isn't the same as a T1. Once you get to 80mm stroke things get extremely complicated in a hurry going longer. Different engines, different combos.

Tom Notch wrote:Stroking a T4 motor isn't the same as a T1. Once you get to 80mm stroke things get extremely complicated in a hurry going longer. Different engines, different combos.

....Why? clearancing a case isnt that tough, what else needs to be done?

68Ghia wrote:You'll never cruise much above 2850. What prop will you be using? Remember tip speed. Once the tip speed goes supersonic you'll lose your "bite" in the air.

Dont know yet, just getting the idea together at this point. If I could build a type 4 motor with enough grunt I wouldnt have to use a gear reduction... and thats how I'm thinking right now. No one sells gear reduction units for flywheel drive type4's at this point. Most of the engines used in the STOL plane I'm looking at use reduction to get more power at the prop for short takeoff... so maybe I'll have to do it.... we'll see what I find out

You're entering into a world where a lot of what you know will be useless. That being said join the EAA and it's local chapter. These guy's love planes like others love cars. They love to help newbies. I'll give youu a for instance. The reduction units you see are to reduce rpm to the prop and are for high reving engines. ie those above 3500rpm or so. You can use that type 4 but you'll need to get some custom heads w/ twin plugs per cylinder, Light Speed probably has a suitable ignition system (mag - it can't depend upon the battery for spark in any manner) that would work on that engine. Your prop will be wood (which comes with it's own set of problems) or one of the new carbon fiber, variable pitch (even reverse!) styles. Why? There ain't enough mass in that type 4 crank. There big but not that big. Comparable A/C engines dwarf type 4 cranks. This is in part due to the mass of A/C metal props. If not, the harmonics would run wild thru that engine and self destruct in short order. Or maybe the prop would destruct first. That wildly out of balance nightmare will usually throw the engine off the plane anyway. And the plane always corkscrews into the ground after that. Have fun, I spent 20 years in it.

The rods hit the cam lobes....you need to study and learn the differences between types (and you are in the right place). Other than both being Air Cooled Flat fours from VW, they don't share architecture, virtually completely different.

Busguy71 wrote:

....Why? clearancing a case isnt that tough, what else needs to be done?

Busguy71 wrote:

68Ghia wrote:You'll never cruise much above 2850. What prop will you be using? Remember tip speed. Once the tip speed goes supersonic you'll lose your "bite" in the air.

Dont know yet, just getting the idea together at this point. If I could build a type 4 motor with enough grunt I wouldnt have to use a gear reduction... and thats how I'm thinking right now. No one sells gear reduction units for flywheel drive type4's at this point. Most of the engines used in the STOL plane I'm looking at use reduction to get more power at the prop for short takeoff... so maybe I'll have to do it.... we'll see what I find out

Actually, there are companies that provide belt driven reduction off the flywheel end of a Type lV.
And a gear driven reduction: See if this link will work for you ? http://www.vw-engines.com/specpage.htm

What kind of cylinders are those Richard?
s

Let me open a can of worms again... ... The Cyl's are 98.4mm and cost $1300...

Let me be the 1st Idiot Parrot to say it...Not... ...Some in house US made 6061 CNC Billet Nikasil Plated Aluminum "Knockoff"... ... Cyl's made for VW Based Aircraft Engines. The rest of the Parrots can argue who they are Knockedoff from... ... But wait, there not designed like any Nikkasil Plated cyl that is currently available(except are designed like current aircooled cyl's for aircraft), but that doesn't matter, cause no one else has the right to make Nikasil Plated Aluminum cyl's... ..due to the fact, as soon as some one does their labeled Knockoffs...

Two different lengths for 2 different strokes.

Are you going to test them out in an automotive app?

s

I would like to but I can't afford them, I can't afford the $700 chinese Nikasils, and right now, I can't even afford the $200 cast iron cyl's...