AN ENGINE FOR HOMEBUILDERS

"Anthony W" wrote

The 3.5 and 4" belt setups are running about $1500 and probably not worth
it for what we're talking about. These belts are for engines that run
over 100 BHP peak and the riders of these bikes can be very abusive when
doing burnouts and drag racing.

Humm, I saw some brand new 3" with 2 pulleys and belt for less than 500
bucks, but they were set up for installing the one pulley on a clutch, so an
adapter would probably have to be made for that one.

If they are available on Ebay for less, that would be what I would consider
reasonable. 500 bucks isn't too far out of reach for most non 3rd world
country resident, either.
--
Jim in NC

I'm running a bit behind on this thread; here are thoughts about a
couple of questions.

Someone mentioned that the industrial engines are a bit heavy. True to a
degree, but if you're designing a plane around the engine (as God
intended) the extra weight is only a minor penalty. Early VW powered
designs had to make do with not much more than 40 hp, & the VW weighed
over 150 lbs. Hundreds of 'Piets' are flying with 35-40 hp Model A
engines that weigh way more than 300 lbs, IIRC. The plane was designed
for the engine. Hanging one on a plane designed for a Rotax won't be too
successful, though. :-)

Someone else mentioned using a heavier cam drive train as the prop
reduction drive. It's been done on certified engines. The problem I've
heard about is that it increases the likelihood of torsional resonance
(supposedly the reason that reduction ratios are almost always some
weird number).

Charlie

On May 25, 5:40*pm, Charlie wrote:


Someone mentioned that the industrial engines are a bit heavy. True to a
degree, but if you're designing a plane around the engine (as God
intended) the extra weight is only a minor penalty.
------------------------------------------------------------------------------------------

Dear Charlie,

Seeking information about TATA's engine line-up, with special interest
toward the most popular and having the longest years of service, I was
told it was a 1403cc I-4 SOHC in both Otto Cycle & Diesel (!!),
offered as an industrial engine, for cars, trucks and even marine
applications.

I guess they do things differently in India because 1403cc is about
85cid -- even the stock 1600cc VW would look like a stump-puller. But
the weight is said to be 'about' 300 lbs (!!!) Which may explain the
ability to use the basic block for a Diesel as well as a SOHC gas
engine.

Any way you slice it, the weight is a tad much.

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

Early VW powered
designs had to make do with not much more than 40 hp...

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

Late ones, too :-)

The VW is thermally limited by its heads, which were designed for the
40hp 1300cc engine. You can increase it's displacement.. . and you
may CLAIM any horsepower you wish.... but you maximum SUSTAINED
output is going to fall in the 40 to 50 hp range, depending on the
local atmosphere. Demand any more and your MTBO takes a major header
into the porcelain fixture. (Engines can't lie. Go by their fuel
consumption figures. The SFO (specific fuel consumption) of all air-
cooled engines is clustered around the 0.5lb/hp mark (Standard Day
assumed, etc.) )

-R.S.Hoover

Veeduber wrote:
On May 25, 5:40 pm, Charlie wrote:

Someone mentioned that the industrial engines are a bit heavy. True to a
degree, but if you're designing a plane around the engine (as God
intended) the extra weight is only a minor penalty.
------------------------------------------------------------------------------------------

Dear Charlie,

Seeking information about TATA's engine line-up, with special interest
toward the most popular and having the longest years of service, I was
told it was a 1403cc I-4 SOHC in both Otto Cycle & Diesel (!!),
offered as an industrial engine, for cars, trucks and even marine
applications.

I guess they do things differently in India because 1403cc is about
85cid -- even the stock 1600cc VW would look like a stump-puller. But
the weight is said to be 'about' 300 lbs (!!!) Which may explain the
ability to use the basic block for a Diesel as well as a SOHC gas
engine.

Any way you slice it, the weight is a tad much.

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

Early VW powered
designs had to make do with not much more than 40 hp...

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

Late ones, too :-)

The VW is thermally limited by its heads, which were designed for the
40hp 1300cc engine. You can increase it's displacement.. . and you
may CLAIM any horsepower you wish.... but you maximum SUSTAINED
output is going to fall in the 40 to 50 hp range, depending on the
local atmosphere. Demand any more and your MTBO takes a major header
into the porcelain fixture. (Engines can't lie. Go by their fuel
consumption figures. The SFO (specific fuel consumption) of all air-
cooled engines is clustered around the 0.5lb/hp mark (Standard Day
assumed, etc.) )

-R.S.Hoover
Hi Bob,

Sorry for the confusion; the industrial engines I was referring to are
the new ones typically used for generators, like the one Valley
Engineering uses.
http://www.culverprops.com/big-twin.php

120 lbs *including a reduction drive and a large diameter prop* for lots
of low speed thrust. I think the direct drive version is under 100 lbs
when stripped for aviation. Their web site is a bit tricky to navigate,
but there's a lot of info on how they did the mods if you dig for it.

The stock engine (unmodified for aviation) is available for around
$3,000, new in box.

Their 'Backyard Flyer' (a couple of different versions on the web site)
using this engine looks a lot like what I would have designed, if I had
the chops. They claim that it's UL-legal, using this 'heavy' engine.
http://www.culverprops.com/back-yard-flyer.php
http://www.culverprops.com/back-yard-ul.php

Oh yeah, someone mentioned motorcycle chain drives. Several years ago
there was a 2 seat pusher UL-like plane based in south Mississippi
flying with (IIRC) a Honda CBR600 shaft drive engine. It was mounted low
in the airframe with a racing chain up to a high-mounted prop shaft in
pillow block bearings. The owner said that he flew in 2nd or 3rd (I
forget which) when solo & downshifted one gear when carrying a
passenger. Apparently it was reliable, because he flew it on cross
countries. I ran the idea past a friend who has raced bikes for most of
his life. He said that it'll work fine if most of the rpm reduction
happens before the chain, but 6K rpm (2 stroke rpms) into the chain
would cause serious issues with the chain trying to turn into a solid
rod entering & leaving the sprocket.

FWIW,

Charlie

"Veeduber" wrote in message
...
------------------------------------------------------------------------------------

Early VW powered
designs had to make do with not much more than 40 hp...

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

Late ones, too :-)

The VW is thermally limited by its heads, which were designed for the
40hp 1300cc engine. You can increase it's displacement.. . and you
may CLAIM any horsepower you wish.... but you maximum SUSTAINED
output is going to fall in the 40 to 50 hp range, depending on the
local atmosphere. Demand any more and your MTBO takes a major header
into the porcelain fixture. (Engines can't lie. Go by their fuel
consumption figures. The SFO (specific fuel consumption) of all air-
cooled engines is clustered around the 0.5lb/hp mark (Standard Day
assumed, etc.) )

-R.S.Hoover

Most of the early VW powered designs, of which I was aware, were designed
and built to work well with a claimed 25 HP. As I recall it, for example,
the Jodel D9 had a wingspan of roughly 23 feet and was supposed to depart
over a 50 foot obstacle in little more than 450 feet and cruise at around 65
mph (about 57 kts) carrying a modest amount of fuel and a 160 pound pilot.
I admit to being about 10 percent heavier than that; but the basic concept
was valid.

Unfortunately, it weighed a little over 300 poinds and the speeds were just
a little above the subsequent Part 103 limits, so interest in that class of
aircraft has been low--even though the stated utility and fuel efficiency
remain better than any of the popular ultralights of which I am aware. My
recollection is that around 1.5 gph was claimed.

Clearly, a 50 HP engine should be able to power a 2 seated of similar
performance, with a gross weight around 1000 pounds. That's as fast as some
of the older "certified" aircraft like the early Cub and the "bathtub"
Aeronca--and it's nearly impossible to maintain 100 percent power for more
than a minute or so with a fixed pitch propeller--so 40 to 50 sustained
horsepower is not necessarily a deterrant for that class of aircraft.

Peter

This website does a bang-up job of running through the options of
various reduction types, and comes down firmly on the side of spur
gears with hydrodynamic bearings:
http://www.epi-eng.com/propeller_red...y_contents.htm

This Polish outfit produces spur gear reductions for various
relatively low power engines:
http://www.aerotech-poland.com/index.php?go=5

I wrote and asked how much:

Hi,
a typical price for gear rd is 1180 EUR + shipping cost.
This price is changing due to currency rates.
Regards
Wlodzimierz Krukowski

They seem to be engine oil lubricated.

"flybynightkarmarepair" wrote in message
...
This website does a bang-up job of running through the options of
various reduction types, and comes down firmly on the side of spur
gears with hydrodynamic bearings:
http://www.epi-eng.com/propeller_red...y_contents.htm

This Polish outfit produces spur gear reductions for various
relatively low power engines:
http://www.aerotech-poland.com/index.php?go=5

I wrote and asked how much:

Hi,
a typical price for gear rd is 1180 EUR + shipping cost.
This price is changing due to currency rates.
Regards
Wlodzimierz Krukowski

They seem to be engine oil lubricated.


Spur geared engines are not generally well thought of by the mechanics with
whom I have talked.

Unless there is a clutch located between the engine crankshaft and the input
shaft of the PSRU, as would normally be the case in an automobile with a
manual transmission, the driving gear will always have the same orientation
with respect to the power pulses of a reciprocating engine. The resulting
uneven wear will ultimately define the replacement interval of the gear(s).

The use of gear ratios that randomize the tooth contact between the driving
and driven gear, or the choice of an engine with a greater number of
cylinders, will serve to mitigate the problem; but a planetary or epicyclic
PSRU will remain the preferred solution whenever there is no randomizing
feature between the crankshaft and the input gear.

Supposedly, cogged belts are imune to the problems; but I suspect it is
simply that the wear rate on the cogged pullies is simply low enough to make
the problem appear trivial. Personally, just to be on the safe side, I
would choose the ratios of both sprockets and the belt to randomize the
contact on a cogged belt drive as well and I would do the same with chain!

Peter

flybynightkarmarepair wrote:
This website does a bang-up job of running through the options of
various reduction types, and comes down firmly on the side of spur
gears with hydrodynamic bearings:
http://www.epi-eng.com/propeller_red...y_contents.htm


I notice this site puts a deal of effort into slagging off a
competitor's sprag clutch use. Without regard to the merits, this is
a warning to me....


Brian W

On May 28, 10:16*am, Brian Whatcott wrote:
flybynightkarmarepair wrote:
This website does a bang-up job of running through the options of
various reduction types, and comes down firmly on the side of spur
gears with hydrodynamic bearings:
http://www.epi-eng.com/propeller_red...earbox_technol...

I notice this site puts a deal of effort into slagging off a
competitor's sprag clutch use. * *Without regard to the merits, this is
a warning to me....

Brian W

I hear where your're coming from, and respect that point of view.

However, that competitor no longer exists. The successor company that
absorbed what was left designed a NEW PSRU from scratch - single
reduction, helical gears, but NOT planetary. No sprag clutch, and a
torsionally soft resilient element between the engine and the gears:
http://www.maxwellpropulsion.com/sportsman/psru.html

Other than the Helical/Spur gear issue, pretty much like EPI
engineering suggests.

OTOH, Real World Solutions has a Ford based planetary out there
racking up hours.

BOTH the RWS and Maxwell Propulsion units are too big and heavy for
the low horsepower applications Veeduber was initially talking about.
The Polish Aerotech unit is the only gear reduction I'm aware of
suitable for smaller engines.

Hello All:

I'm not sure if it was this thread or another similar one, but someone
suggested reverse engineering a Pobjoy engine - if one could be found.
Read the last post in the following thread for a link to one that is
on display in a museum (at South County Airport in Northern CA):

http://www.warbirdinformationexchang...ic.php?p=20143

Dave