Engine and Prop Q & A


From Danrihn@aol.com
I recommend using a Sensenich 76x62 Metal prop for the best peformance.  If you want wood, use a Sensenich wood prop, same diameter and pitch.  I don't recomend any other fixed pitch props.  I am keeping a sharp eye on the Whirlwind props, I want to see more time in the field for this company and their designs.

From: DDavila546@aol.com

based on experience, outlet size needs to be slightly larger than inlet size. At least 10% larger up to 50% larger, depending on how well you sealed your baffles and speed of the plane. since these airplanes spend a lot of time working in fairly slow speed regimes, I plan on about  140%  outlet, after deducting the room the exhaust takes up. I haven't fit my cowl yet so am not sure how much i can really get. Take a look at Sean Tuckers new plane, he has "gills" on the side of the cowl for cooling exit in any attitude in addition to the bottom.

From : Danrihn@aol.com

A good rule of thumb is that the exit area should be 10% greater than entry area.  Lower pressure at the exit allowing the air to flow from top to bottom.

From: DDavila546@aol.com

Why use a gascolator at all? i threw mine away three airplanes ago and haven't missed it at all. A drain on the bottom of the tank to check for water and a GOOD inline fuel filter have worked well for me and I don't have to worry about the gascolator leaking or getting knocked  off (both of which ihave seen, I bet you have too if you think about it.)

From Danrihn@aol.com

I have seen the two front induction tubes modified to fit.  Can't say for sure what this will do the performance of the engine.  You can call Sky Dynamics, 540-297-6754 (ask for Kevin Murray) he is very knowledgeable on induction systems.  He builds the cold air induction system. 

From Danrihn@aol.com

This is an engine I speced out with Lycoming.  It has a front mounted prop governor, a forward facing fuel servo (fuel injector RSA-5), light starter, heavy crank shaft flnage with no lightning holes.  It was put together at my request and is the engine no on the OneDesign prototype.  If you have ever seen this airplane fly with a smoke system, you have seen this engine fly in a One Design.

From:  DDavila546@aol.com

6th and 8th order counter weights are good for smoothness but can be "detuned" by rapid throttle movement,(this from a Lycoming rep years ago)also they add weight, 1 or 2 lbs , we don't need any ballast in the front of these things do we? I plan on using a 200 in my project with a light prop...any of you guys with this combination care to comment on how it works for you? Enough of these things are flying now that we should be able to get some good feedback on flying as well as building...By the way Roger Rourkes cowl is made to fit a 200...i've got the cowl but not the engine so can't comment on fit yet


Hints and Tips

Starters
From: akrotodd@hotmail.com
Comments: Be careful when somebody builds you an engine and tells you you're getting a "Lightweight Starter."  I wrongly assumed I would be the proud owner of either a B&C or a Sky-Tec on my IO-360-A1A, but instead I got a car starter on a funky bracket.  If I want to use this thing, it means putting a bubble in the front of my cowl to clear a boss that doesn't exist on the airplane lightweight starters.

 

Engines
From: Danrihn@aol.com
Here are the various weights of aerobatic engines from Lycoming-
These weights include;
Basic engine, Aerobatic components, Fuel injector (RSA-5), Fuel Pump, Magnetos, Spark plugs, Ignition system, Inter cylinder Baffles, Tach. Drive, Sarter and alternator ring gear, Starter (Heavy- 16.98# Pestolite), Alternator ( Heavy- 13.00# Prestolite)
AEIO-320 160 HP = 301 lbs (232.98 lbs Basic engine)
AEIO-360 180 HP = 304 to 313 lbs depending on model (235.82 to 244.22 lbs Basic engine)
AEIO-360 200 HP = 332 to 339 lbs depending on model (264.21 to 268.6 lbs Basic engine)
Several pounds can easily be saved by using a light weight starter and alternator. I have had good luck with B+C products. The Skytech starter is also very good. Both companies have given me excellent customer support.
Also note that the AEIO-360-A1E and -A1E6, the 200 HP engines are also known as angle valve engines. These engines are not legal One Design catagory engines.
Propellers:
From: flyinut@ncnol.com
Whirlwind Propellers offers a good composite prop for 180hp+ engines and has spinner to fit. I currently am flying behind one of these props on a 200hp S-1S and it is great. Web page is www.concentric.net/~Wwpc/ email wwpc@concentric.net

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