I'm calling it The Little Mermaid

[Montblack]

High Performance Aircraft out of Germany - HPA TT62
http://www.hp-aircraft.de/edoc/tech.html

Two Thielert Centurion 4.0 V8-Diesels - turbocharged and liquid cooled. The
engines are positioned side-by-side inside the aft fuselage. Each engine
drives a five bladed prop mounted on a pylon.


Looks like the Germans went way back to the drawing board, like 1903.

[Daydreaming] ...make it a single 4 cylinder diesel engine. Two pylon props,
two seats in tandem, FG, then give it a pointy nose with a sliding fighter
canopy. Now that would be a cool (looking) little plane. (Scroll down in the
link to the front-on view of the plane to see what I mean) Something the
size of an RV-4 would be good.

I'm calling it The Little Mermaid.

Wonder if for all the trade-offs and compromises, you gain anything with one
engine and two pylon props?


Montblack

[Montblack]

>(Scroll down in the link to the front-on view of the plane to see what I
>mean)


This link has the head-on photo (part way down the page)
http://www.hp-aircraft.de/edoc/news.html


Montblack

[Rich S.]

"Montblack" > wrote in message
...
> High Performance Aircraft out of Germany - HPA TT62
> http://www.hp-aircraft.de/edoc/tech.html
>
> Two Thielert Centurion 4.0 V8-Diesels - turbocharged and liquid cooled.
> The engines are positioned side-by-side inside the aft fuselage. Each
> engine drives a five bladed prop mounted on a pylon.

Hmmm....... Five seats and a 594 lb. useful load at full fuel. Trade-off I
guess.

Rich S.

[Icebound]

"Montblack" > wrote in message
...
> High Performance Aircraft out of Germany - HPA TT62
> http://www.hp-aircraft.de/edoc/tech.html
>
> Two Thielert Centurion 4.0 V8-Diesels - turbocharged and liquid cooled.
> The engines are positioned side-by-side inside the aft fuselage. Each
> engine drives a five bladed prop mounted on a pylon.
>
>
....
>
> Wonder if for all the trade-offs and compromises, you gain anything with
> one engine and two pylon props?
>

Maybe this quote on another page from that site tells it all:

quote:
The first flight has been done successfully but the anticipitations (sic)
in the performance dates [sic... probably meant "anticipated performance
data"] of the TT62 could not be shown satisfactorily. The engineers were not
satisfied totally. Now the evaluation has started and that will be a lot of
work.
:unquote

[Bill Daniels]

"Rich S." > wrote in message
...

> Hmmm....... Five seats and a 594 lb. useful load at full fuel. Trade-off I
> guess.
>
> Rich S.
>
Crap! They need larger tanks.

A solo Atlantic crossing would leave those 594 pounds (less pilot and
toothbrush) unavailable for fuel.

If you need more payload, just don't fill the tanks to the top.

Bill Daniels

[jsmith]

It's a twin!
It will always be a tradeoff.

Rich S. wrote:
> Hmmm....... Five seats and a 594 lb. useful load at full fuel. Trade-off I
> guess.

[Rich S.]

"jsmith" > wrote in message
...
> It's a twin!
> It will always be a tradeoff.
>
> Rich S. wrote:
>> Hmmm....... Five seats and a 594 lb. useful load at full fuel. Trade-off
>> I guess.
>

But I wanted to load Ammeter on board, fly to Kansas (or Iowa or where ever
inthehell he is) pick up Oyster and fly'em both to Oshkosh.

Rich "What was the phone number for that Russky transport company?" S.

[John Ammeter]

On Mon, 14 Mar 2005 13:01:43 -0800, "Rich S."
> wrote:

>"jsmith" > wrote in message
...
>> It's a twin!
>> It will always be a tradeoff.
>>
>> Rich S. wrote:
>>> Hmmm....... Five seats and a 594 lb. useful load at full fuel. Trade-off
>>> I guess.
>>
>
>But I wanted to load Ammeter on board, fly to Kansas (or Iowa or where ever
>inthehell he is) pick up Oyster and fly'em both to Oshkosh.
>
>Rich "What was the phone number for that Russky transport company?" S.
>


Hmmm 594 pounds useful load?? Ok, that's Oyster and me if
we don't bring any baggage. You can take the train and meet
us there...

John

[Larry Dighera]

On Mon, 14 Mar 2005 12:38:56 -0600, "Montblack"
> wrote in
>::

>High Performance Aircraft out of Germany - HPA TT62
>http://www.hp-aircraft.de/edoc/tech.html

It's an interesting design. Is it a home built?

[Rich S.]

"John Ammeter" > wrote in message
...
>
> Hmmm 594 pounds useful load?? Ok, that's Oyster and me if
> we don't bring any baggage. You can take the train and meet
> us there...

I'm thinkin' we need three of them and we could start an aerobatic team. Das
Wunderkind??

Rich S.

[Montblack]

("Larry Dighera" wrote)
> It's an interesting design. Is it a home built?


I didn't get the feeling from their web page it was being offered for the
homebuilt market.

http://www.hp-aircraft.de/edoc/news.html
Looks like a start-up company - news.

Now, The Little Mermaid, that would be a homebuilt :-)


Montblack

[Morgans]

2
"John Ammeter" > wrote in

>
> Hmmm 594 pounds useful load?? Ok, that's Oyster and me if
> we don't bring any baggage. You can take the train and meet
> us there...
>
> John

No, just stop every 30 minutes or so, for fuel. <g>
--
Jim (ducking) in NC

[Morgans]

"Montblack" > wrote
>
> Wonder if for all the trade-offs and compromises, you gain anything with
one
> engine and two pylon props?
>
>
> Montblack

I think so. Not too far off from my musings. Take a liquid cooled
motorcycle engine, run dual drive belts, one out each of the pylon mounts,
and with the smaller diameter props, you could run them faster to take
advantage of the high revving engine. You get to use Harley sized drive
belts and sprockets, readily available in junkyards everywhere. (the
sprockets, I mean)

I read about some guy that was running a motorcycle engine, and even
shifting in flight for cruise.

My ideal sport plane would be an amphibian, if they get the rotating landing
gear back in.
--
Jim in NC

[George Patterson]

Montblack wrote:
>
> >(Scroll down in the link to the front-on view of the plane to see what I
> >mean)
>
> This link has the head-on photo (part way down the page)
> http://www.hp-aircraft.de/edoc/news.html

I get "error 404: Datei nicht gefunden! Das angegebene Dokument konnte auf
diesem Server leider nicht gefunden werden." on both of those links.

First time I've seen that in Deutsch.

George Patterson
I prefer Heaven for climate but Hell for company.

[UltraJohn]

George Patterson wrote:

>
>
> Montblack wrote:
>>
>> >(Scroll down in the link to the front-on view of the plane to see what I
>> >mean)
>>
>> This link has the head-on photo (part way down the page)
>> http://www.hp-aircraft.de/edoc/news.html
>
> I get "error 404: Datei nicht gefunden! Das angegebene Dokument konnte auf
> diesem Server leider nicht gefunden werden." on both of those links.
>
> First time I've seen that in Deutsch.
>
> George Patterson
> I prefer Heaven for climate but Hell for company.


Both links worked here!
Sorry <g>
John

[Jose]

> Take a liquid cooled
> motorcycle engine, run dual drive belts, one out each of the pylon mounts,
> and with the smaller diameter props, you could run them faster to take
> advantage of the high revving engine.

Engines run better when fast, props work better when slow. If you're
using a belt drive anyway, there's no point in running the props fast.
Let the belt apply the high engine speed to a large, slow prop.

Jose
(I left r.a.homebuilt in, though I don't follow that group)
--
Math is a game. The object of the game is to figure out the rules.
for Email, make the obvious change in the address.

[Morgans]

"Jose" > wrote
>
> Engines run better when fast, props work better when slow. If you're
> using a belt drive anyway, there's no point in running the props fast.
> Let the belt apply the high engine speed to a large, slow prop.
>
> Jose
> (I left r.a.homebuilt in, though I don't follow that group)

You are missing the point. Take a small engine, divide the output in half,
and the prop is going to be small. Small props do not mind turning fast.
Also, if you use the belts for the RPM reduction, you have to put the big
pulley out on the pylon, where you want a small one.
--
Jim in NC

[Jose]

> You are missing the point. Take a small engine, divide the output in half,
> and the prop is going to be small.

Why?

> Small props do not mind turning fast.

No, they don't mind at all. But as I understand it they aren't as
efficient as large props turning slowly.

> Also, if you use the belts for the RPM reduction, you have to put the big
> pulley out on the pylon, where you want a small one.

Or you use a gear at the engine. Point is, once you're not direct
drive, the engine speed is no longer required to be the same as the prop
speed.

Jose
(r.a.homebuilt left in, though I don't follow that group)
--
Math is a game. The object of the game is to figure out the rules.
for Email, make the obvious change in the address.

[Montblack]

("Morgans" wrote)
> My ideal sport plane would be an amphibian, if they get the rotating
> landing gear back in.


http://www.beriev-usa.com/main/index.html
(You're half way there with this Russian number)

http://web.media.mit.edu/~tim/pix/oshkosh03_1/0788.jpg
(At Oshkosh)

http://web.media.mit.edu/~tim/pix/oshkosh03_1/0791.jpg
(At Oshkosh)


Montblack

[Morgans]

"Jose" > wrote in message news:b8uZd.5306

> > You are missing the point. Take a small engine, divide the output in
half,
> > and the prop is going to be small.
>
> Why?
>
Because I can. Because that would divide the HP into two, so a smaller size
bike belt would be reliable. Pay attention.
--
Jim in NC

[Larry Dighera]

On Mon, 14 Mar 2005 19:45:09 -0600, "Montblack"
> wrote in
>::

>("Larry Dighera" wrote)
>> It's an interesting design. Is it a home built?
>
>
>I didn't get the feeling from their web page it was being offered for the
>homebuilt market.

Then, why'd you crosspost to rec.aviation.homebuilt?

[Jose]

>>>You are missing the point. Take a small engine, divide the output in
>>> half, and the prop is going to be small.
>>
>> Why?
>
> Because I can. Because that would divide the HP into two, so a smaller size
> bike belt would be reliable. Pay attention.

I am paying attention. I'm trying to learn something, no need to be rude.

Seems to me that dividing the HP in two does not mean a smaller prop.
The same HP can turn a large prop slowly or a small prop quickly. The
same power goes into each prop no matter what. However, with a large
prop turning slowly, the =force= on the prop would be smaller (so force
times distance remains constant). But the force on the belt should be
the same, since the belt is turning at engine speed around the engine
shaft, (and at prop speed around the bigger prop shaft).

What I have read indicates that props are more efficient turning slower
(than 2500 RPM) and (gas) engines are more efficient turning faster than
that. Aside from the issue of the large prop pully at the pylon, what
am I missing?

Jose
r.a.homebuilt trimmed, as I don't follow that group
--
Math is a game. The object of the game is to figure out the rules.
for Email, make the obvious change in the address.

[MJC]

I'm calling it "dead in the water" :-)

MJC

"Montblack" > wrote in message
...
> High Performance Aircraft out of Germany - HPA TT62
> http://www.hp-aircraft.de/edoc/tech.html
>
>
> I'm calling it The Little Mermaid.
>
Montblack
>

[Montblack]

("Larry Dighera" wrote)
>>I didn't get the feeling from their web page it was being offered for the
>>homebuilt market.
>
> Then, why'd you crosspost to rec.aviation.homebuilt?


A: It's an interesting idea ...with pictures.

B: It's spawned some "what if" ideas based on HPA's design.
http://www.hp-aircraft.de/edoc/tech.html

C: It's gennerating an interesting belt-drive propeller discussion. Very
1903. <g>

D: It's not like I cross-posted The Little Mermaid to
rec.shipping.propulsion.


May I please have my hall pass back?


Montblack

[Morgans]

"Jose" > wrote i> What I have read indicates that
props are more efficient turning slower
> (than 2500 RPM) and (gas) engines are more efficient turning faster than
> that. Aside from the issue of the large prop pully at the pylon, what
> am I missing?
>
> Jose

OK, I'll be nice, since you asked so nice. ;-)

Homebuilt group is really where this discussion belongs, but whatever. It
is an interesting group, if you like discussions like this.

Yes, big props are turning slowly are more efficient, and more efficient,
especially at climb. Smaller faster props work better for speed in cruise.

The big pulley out on the pylon is a big drawback, due to drag where you
don't want it. The other problem of trying to get it to turn slower, is
that it would need to done by using gearing, and the gearing I was talking
about was a motorcycle gearbox They have been shown to have durability
problems, when running a low gear at high power for extended periods of
time.

The whole issue of a smaller prop turning fast is not that big of a deal, as
long as it is not too fast. Yes, the tips definitely have to stay out of
the supersonic flow, where big losses occur. There are many very successful
designs running around on engines like Volkswagen engines, or Subaru direct
drives, or even the small Continentals trying to make more HP.
--
Jim in NC

[Highflyer]

:Yes, that is all true. The real problem is the rapid decline in the
efficiency of conversion from power to thrust as the propellor rpm
increases. The pounds of thrust per horsepower declines like a capacitor
discharge curve as the rpm increases and you have lost two thirds by the
time the prop rpm gets to 2000!

A ducted fan helps a little, but they are much less efficient than a big old
lazy unshrouded propellor chugging away.

Highflyer
Highflight Aviation Services
Pinckneyville Airport ( KPJY )

PS: Pinckneyville rec.aviation flyin is coming up May 20, 21, and 22. See
the article in AOPA Online.
"Morgans" > > You are missing the point. Take a
small engine, divide the output in half,
> and the prop is going to be small. Small props do not mind turning fast.
> Also, if you use the belts for the RPM reduction, you have to put the big
> pulley out on the pylon, where you want a small one.
> --
> Jim in NC
>
>