**The intended Sonex Powerplant**

============================================

**Exploded Drawings of the Type 4 Long Block (Aug. 2nd,
2001)**

If you have some strange looking parts left over and don't know where to put them on, the following sketches may be helpful.

All pics are of high resolution and most are larger than the usual computer screen. So it's best you download the pic and use your favourite picture viewer to examine it offline.

**Engine Case** (GIF,
97KB)

**Cylinder Head** (GIF,
59KB)

**Crank** (GIF,
66KB)

**Cylinder** (GIF,
28KB)

**Cam & Lifter** (GIF, 69KB)

**Oil Pump & Filter**
(GIF, 53KB)

**Breather & Dipstick** (GIF, 83KB)

**Inition**
(GIF, 64KB)

**Starter**
(GIF, 163KB)

**Fuel Pump**
(GIF, 56KB)

============================================

**A Commercially Oriented Powerplant Reality Check**

I have researched the German 'Aircooled VW' scene now for quite a while. I have read several books, studied intensively the internet and have collected catalogs of the most reputed aircoolded VW rebuilders/tuners. This is what came out so far:

- my proposed type 4 engine will be 'as new' when ready (all new/overhauled internal parts)
- will have no fancy parts, but all quality parts.
- will have no extreme modifications (103 bore x 71 stroke = 2.4L)
- will have critical parts (cyl- stud bolts, case bolts) in high strength quality
- will have internal parts lightened and friction reduced (needle bearings)
- will have all turning parts balanced and matched

If machining is being done by a specialist rebuilder, then the price will be somewhere around

DM **10 000** (or about USD 4 500)

for the basic engine. This is with exhaust and muffler but **without
ignition and carburetion** (and wiring and small parts and baffling and
and and ...).

The engine should provide a solid 90HP takeoff power (which I may need for my expected overweighted flying machine).

Compared to the 2200 Jabiru 80HP engine the end result may be in par in money, however the type 4 will consume another several hundred work (or fun) hours. The Jabiru may be the more proven/reliable product, but the type 4 I'll know then in and out by heart (and it hopefully will deliver a few more horses).

Maintenance for the type 4 is expected to be cheaper than for the Jabiru.

The Jab I will have to pay in one sum, the type 4 I can 'stretch' in several smaller amounts over the time of the rebuild.

The Jab 3300 is financially out of my reach. The Corvair engine is not available/unknown in Germany. The Type 1 (Great Plains) is too weak. Rotax 912 is too expensive and there's no support from the airplane designer (Sonex-Ltd).

The type 4 will be my on creation.

============================================

**This is a GREAT program for developing a 'paper'-engine**

**(and to refute a lot of HP claims from several
auto-aviation converting firms)**

**When removing the case bolts and cylinder studs
(M10x1.5 rolled fine thread), the threads were covered with a very stout
varnish.**

**Very hard to remove. A good idea came from Bob
Hoover (Veedubber) from the VW email list (highly recommended). He proposed
to split a nut and use this one as a thread cleaner.**

**Works great. A regular threaded die should not
be used for this cleaning job, because the rolled bolt threads might be
hurt.**

**T4-Cases**

**If you decide to go with a Type 4 VW engine
(which I think will make sense...), then check the following when you buy
the core for your rebuilding project:**

The engine case has an identification stamp near the breather case (fan end). At least in Germany the ID is extended with an 'X' if the engine has already been rebuilt. THIS IS A BAD SIGN! The engine case can be rebuild/bored TWO times, then it's ready for the junkyard. So look out for a normally worn-out engine without an rebuild history!

**============================================**

**This is an interesting link for a homemade EFI
system (I believe more in this**

**technology than 100-year's old dripping carburetor)**

**============================================**

**this one is a very nice collection of engine
calculation programs. Here I found that compression ratio of 7.5 instead
of 8.0 only cost me 2 hp for an 80 hp engine (but is much nicer to the cylinder
heads) - HOWEVER - a 2.2L engine with compression ratio of 8.0 (Great Plains
VW) gives me only a little of 62 hp at 3200 rpm (what I always have been
afraid of).**

**============================================**

**nice collection of VW aircooled engine rebuilding
and maintenance tips**

**============================================**

**here is a complete Porsche 914 ('VW'-Porsche)
Type-4 engine parts-list in microfiche form. This could be the engine of
choice for my aero-engine conversion...**

http://www.mittelmotor.de/deutsch/ersatzteile/porsche914/01motor914.htm

**============================================**

**Universal Formulas**

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Im Allgemeinen wird die Schallgeschwindigkeit nur in Abhängigkeit von der

Temperatur angegeben (die allerdings z.B. mit der Flughöhe abnimmt):

a=sqrt(k*R*T)

Hierin sind

a: Schallgeschwindigkeit in [m/s]

k (kappa): der Isentropenexponent der Luft = 1.4

R: die Universelle Gaskonstante = 287 [J/(kg*K)]

T: die absolute Temperatur in [K], wobei T(K)=t(°C)+288.15

Bei Raumtemperatur (20°C = 308.15 K) also: a = sqrt(1.4*287*308.15) = 351.87

[m/s] = 1266.74 [km/h].

**HORSEPOWER/THRUST/ calculations / estimations**

Horsepower = torque * RPM / 5252

------------------------------------------------------------------------------------------------------------

There is a formula for calculating horsepower from CFM....... displacement

divided by 2 times RPM divided by 1728 gives theoretical CFM. Actual CFM

will be about 85% at max rated power for most engines, so multiply by .85 to

get a realistic actual CFM. Divide CFM by 1.62 to get SAE horsepower.

The easy way is to multiply displacement in liters by RPM in hundreds and

multiply by .926.

A 1600 engine naturally aspirated turning 4500.....

1.6 * 45 = 72

72*.926 = 66.67 HP

H.W., VW@lists.kz, Jul 24, 2000

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Here's some good words on thrust

It seems like it's back to front - but in a recip engine developing constant

power, the thrust produced by the prop decreases as speed increases - in

order to maintain a basic relationship, that

speed times thrust = a constant number.

There is a limit to this rule however - else at a ground tether (speed = zero)

the thrust would be infinite and it isn't. You would want the prop's

max angle of attack to be happening just under stall speed, for best escape

from stalling, and have the prop more and more stalled at slower speeds,

so the prop drag is higher, even if the thrust is high.

Here's a sample calculation, 50 HP at 50 mph (in SI, for laughs)

We choose a VW that develops 50hp say = 50 x 746 watts = 37.3 kW

Plane is taking off at 50 mph say = 22.4 meter/sec

Remembering thrust times speed = power

so thrust x 22.4 = 37.3 x 1000

so thrust = 37.3 x 1000 / 22.4 = 1665 newtons

(Thats 373.4 lbs, found by multiplying newtons by 2.2/9.81)

That's about as much thrust as yer VW thust washers need to take care of.

Less at higher speeds.

Brian W, VW@lists.kz, Mar 19, 2000

The "limits" can come with a very small increase in rpm sometimes. Here is a

formula for horsepower that really helps the engine builder or modifier:

PLANk

P is for PRESSURE - more specifically, Brake Mean Effective Pressure

(BMEP) which is the average pressure inside the cylinder.

L is for STROKE - the distance the piston moves from bottom to top

A is for AREA - of all the cylinder circles -

(bore / 2 * bore / 2 * 3.14 * numberofcylinders)

N is for RPM - what Gordon said! Double N and HP doubles!

****ALL ELSE BEING EQUAL**** which is very difficult.

k is finagle's factor - it is adjusted to accomodate such things as

whether measurements are in feet, inches or millemeters etc.

Hal Kempthorne, rv-list@matronics.com, Mar. 23, 1999

To get the speed increase you take the new hp's divide with the "old"

like 125/100=1,25 then the 3rd root out of that = 1,077 that's 7,7% increase

of speed with 25% more HP's.

that's if the propeller(s) is right!

Jan Carlsson @RAH, Mar. 09, 2001

**TUNED INTAKE/EXHAUST**

All of the above cover the basics of tuned inlets and exhaust systems.

Smith gets complicated with theory of waves etc. Bell gives graphs of

measured optimum lengths for different engines. Simplest coverage and what

I think is the best read is in Campbell's book. He gives suggested inlet

and exhaust lengths at rpm:

RPM Inlet" Exhaust"

2000 46 100

3000 31 68

4000 24 50

All lengths measured from the valve. These values equate with the lengths

given in the other books.

As I understand things 4 into 2 systems can work well using the tuned length

system, but equal firing spaces are desirable, which requires the front

cylinders to be paired, separate from the rear.

JohnD, VW@lists.kz, Feb. 07, 2000

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**ALTITUDE, RATE OF CLIMB, SPEED formulas**

TAS=CAS*sqrt(rho0/rho(h))

Im Allgemeinen wird die Schallgeschwindigkeit nur in Abhängigkeit von der

Temperatur angegeben (die allerdings z.B. mit der Flughöhe abnimmt):

a=sqrt(k*R*T)

Hierin sind

a: Schallgeschwindigkeit in [m/s]

k (kappa): der Isentropenexponent der Luft = 1.4

R: die Universelle Gaskonstante = 287 [J/(kg*K)]

T: die absolute Temperatur in [K], wobei T(K)=t(°C)+288.15

Bei Raumtemperatur (20°C = 308.15 K) also: a = sqrt(1.4*287*308.15) = 351.87

[m/s] = 1266.74 [km/h].

Philipp, de.rec.luftfahrt Sept. 27,2000

Für aerodynamische Kräfte

( F = q * c * A )

ist der Staudruck

( q = 0,5 * rho * v * v )

ausschlaggebend. Neben der Dichte kommt in der Formel noch das v vor.

Und dieses v ist die wahre Eigengeschwindigkeit.

Lars, de.rec.luftfahrt June. 07,200

------------------------------------------------------------------------------------------------------------

If everything else is the same, it is easy to estimate the change in

rate of climb with change in power. At the same weight, and speed,

the drag is the same, so any extra power increases the climb rate.

Lets assume a propeller efficiency of 75%, so we only get to use 15

of the extra 20 hp (assuming that the 160 hp with constant speed is

the baseline).

Power = rate of doing work. 1 Horsepower = 33,000 ft-lb/min.

We are lifting a 1650 lb aircraft.

Extra rate of climb = 20 X 0.75 X 33,000/1650 = 300 ft/min.

Actual results will vary due to prop efficiency being a bit different

from the assumed value, variations in power output of engines and

variations between aircraft that affect drag.

Kevin Horton, rv-list@matronics.com, Mar, 24, 1999

**Engine Certification**

The document that governs any certification of any

aircraft engine (be it reciprocating piston engines or

turbine) is Advisory Circular AC33-2B, "AIRCRAFT ENGINE

TYPE CERTIFICATION HANDBOOK".

To cut to the chase; only 150 hours are required to

certify ANY aircraft engine! And so as not to bore y'all

I'll give you the pertinent sections (brutally and

severely edited). Every combination you can think of is

covered in the manual. Single-speed supercharged,

double-speed supercharged, turbocharged, gear driven,

helicopter engines, etc. are all covered in the manual.

Prop, accessories and other good stuff are all addressed

in testing.

Section 33.49 Endurance Test

a.) General...during the runs at rated takeoff power and

for at least 35 hours at rated maximum continuos power,

one cylinder, must be...not less than limiting temp, the

other cylinders must be operated at not less than 50 deg

below the limiting temp...

b.) Unsupercharged engines. . . (1) 30 hr run...alternate

periods of 5 minutes rated take off power...5 min best

economy (2) 20 hr...alternate periods 1.5 hr @max...1/2

hr @ 75%&91% (3) 20 hr...alternate periods 1.5 hr

@max...1/2 hr @ 70%&89% (4) 20 hr...alternate periods 1.5

hr @max...1/2 hr @ 65%&87% (5) 20 hr...alternate periods

1.5 hr @max...1/2 hr @ 60%&84.5% (6) 20 hr...alternate

periods 1.5 hr @max...1/2 hr @ 50%&79.5% (7) 20

hr...alternate periods 2.5 hr @max...2 1/2 hrs max best

economy...

Ross, kr-net@telelists.com, Jan., 11, 1999