Hi Owen,
The US has an active Auxiliary Powered Sailplane group with a web site at:
http://mysite.verizon.net/engreenwell/ASA/index.html
From what I have seen in the past they have some good articles and
publications available from the site that might help you get started. If you
have any furt
Yes, but it isn't straightforward, which is why people keep refering to
either thrust for jets and horses for props.
It is probably easier to convert horsepower to thrust - but you will
need a chart of your propeller efficiency.
-Original Message-
Anyone know the relationship between t
Dear Owen
Some references which mainly deal with Self-Launching motorgliders but which
also have some relevancy:
"A Guide to Self-Launching Sailplane Operations" by Eric Greenwell 3rd
Edition, downloadable from the US Auxiliary Powered Sailplane Association
website.
Motorgliding & Gliding Interna
At 21:36 25/03/2007, you wrote:
Yes, but it isn't straightforward, which is why people keep refering to
either thrust for jets and horses for props.
It is probably easier to convert horsepower to thrust - but you will
need a chart of your propeller efficiency.
-Original Message-
Anyo
$US750 IM
- Original Message -
From: Ben Jones
To: Discussion of issues relating to Soaring in Australia.
Sent: Friday, March 23, 2007 7:20 PM
Subject: Re: [Aus-soaring] Fw: [jabiruengines] Microair Radios
Ian,
Is the $750.00 price tag in USD, if it is it equates to the
Actual Thrust = prop efficiency x power / speed.
Working out the prop efficiency is the interesting bit.
-Original Message-
From: Mike Cleaver [mailto:[EMAIL PROTECTED]
Sent: Sunday, 25 March 2007 10:32 PM
To: [EMAIL PROTECTED]; Discussion of issues relating to
Soaring in Australia.
Subj
Geez, I haven't seen the old "slugs" quoted for one hell of a long time.
Does this mean good old "Christian" units are making a comeback? Are we
going to start quantifying our outlanding paddocks in Roods, Poles and
Perches? I had better dig out my old survey chain...
Allan Armistead
ph (02) 6249
Hi all,
Let me rephrase the question, what is the conversion for thrust to
horsepower assuming 0 airspeed, idea being what acceleration a jet powered
glider will have from a standing start, ie takeoff?
Regards
Dave
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On
A good "rule of thumb" for take off calculations is
(0.7 x static thrust) / AUW, which gives acceleration in "g"
(which is a very small figure)
The 0.7 is to average thrust during the ground roll, since increasing ram
drag reduces net thrust with increasing speed, making the calculation
easier
Paul Mander plans to fit 2 x 70kg thrust jets to his ASH25, I believe he is
only a few months away from this happening. Also I saw some photos of an
ASW20?? At Corowa fitted with a jet - did it ever fly? There is also a Swiss
company selling a bolt on jet pack for gliders, they do not retract it as
Hi all,
Just came across a new data logger. at a quite reasonable price, the EW
microrecorder. FAI certified and 30 hours on 2 x AA NIMH batteries!
Also provides regulated 5v supply for PDA when powered from 12v.
See http://www.ewuk.co.uk/products/microRecorder/microRecorder.html
Looks pretty
At 08:52 AM 26/03/2007, you wrote:
Hi all,
Let me rephrase the question, what is the conversion for thrust to
horsepower assuming 0 airspeed, idea being what acceleration a jet powered
glider will have from a standing start, ie takeoff?
Regards
Dave
Acceleration is force/mass
The accelerati
Peter Creswick wrote:
A good "rule of thumb" for take off calculations is
(0.7 x static thrust) / AUW, which gives acceleration in "g"
(which is a very small figure)
The 0.7 is to average thrust during the ground roll, since increasing
ram drag reduces net thrust with increasing speed, making
Allan Armistead wrote:
Geez, I haven't seen the old "slugs" quoted for one hell of a long time.
Does this mean good old "Christian" units are making a comeback? Are we
going to start quantifying our outlanding paddocks in Roods, Poles and
Perches? I had better dig out my old survey chain...
Go
At 10:10 AM 26/03/2007, you wrote:
The kicker is the static thrust - which is modified by the Froude
efficiency. Basically, this is the ratio between the speed of the
aircraft divided by the speed of the gas leaving the jet engine
nozzle. So when the glider is stationary, the Froude efficiency
Robert, have you heard of any of these high bypass jets being developed for
models and UAV's etc? Will be interesting to see how Mikes combo goes, I
would prefer a single engine solution though.
Great to see some meaningful discussion where you get to learn something!
Nig
Peter Creswick wrote:
So I guess you won't be going the turboprop route then...
http://microjeteng.com/prop.html
> -Original Message-
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On Behalf
> Of Mike Borgelt
> Sent: Monday, 26 March 2007 10:46 AM
> To: Discussion of issues relating to Soaring in
Would anyone be able to point me in the right direction to find a website
showing a sketch or drawing of a Bendix gear assembly (used on a Bellance
Scout or similar)?
Peter Carey
E.R.I.Corporation Pty.Ltd.
Mobile:: 0412464340
>From overseas: +61412464340
__
There are quite a number of low bypass and mid bypass ratio
turbo fans around. Unfortunately they are only one use
engines designed for cruise missles. It isn't too much of a
step to take the engine and redesign it for multiple use.
> Robert, have you heard of any of these high bypass jets
> b
>From a standing start the prop will probably get around
50-55kg thrust depending on engine and prop.
As you get moving the props ability to produce thrust will
start to reduce but the jet will keep on producing a
relatively constant thrust.
You will get to a speed where the jet will start prod
At 11:24 AM 26/03/2007, you wrote:
There are quite a number of low bypass and mid bypass ratio
turbo fans around. Unfortunately they are only one use
engines designed for cruise missles. It isn't too much of a
step to take the engine and redesign it for multiple use.
Even assuming you could
So what is the cost of the engines you are considering Mike?
> -Original Message-
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On Behalf
> Of Mike Borgelt
> Sent: Monday, 26 March 2007 12:15 PM
> To: [EMAIL PROTECTED]; Discussion of issues
> relating to Soaring in Australi
Mike Borgelt wrote:
Two engines have lots of advantages when you think about it for a while.
Certainly - but they also have their downsides - increased complexity of
controls, fuel runs etc. I am not too much worried about an engine
failure in a jet powered glider as it will present only one ad
nandrews wrote:
Robert, have you heard of any of these high bypass jets being developed for
models and UAV's etc? Will be interesting to see how Mikes combo goes, I
would prefer a single engine solution though.
My 'info' is that the US military are demanding a turbofan option, but
there is quite
Derek Ruddock wrote:
So I guess you won't be going the turboprop route then...
http://microjeteng.com/prop.html
The current self launch options are bad not because of the engine but
because of the huge drag penalty of that unpowered prop prestart. The
huge advantage of jet is that they cost
At 12:39 PM 26/03/2007, you wrote:
I have heard (but cannot point at a source) that small turbofans are
being developed with a single shaft and turbine.
Doesn't sound right to me. The turbofan design I've seen had an aft
fan driven by its own free turbine just like the Whittle patent. The
s
on behalf of Andrew W
** Forwarded Message Follows ***
--- Begin Message ---
Hello Anthony
(I can not submit to Aus-soaring but this might be interesting for the
group to know.)
A company overseas called "Jet RPM" already has retrofit jet
engines from 30 to 70 kg thrust for glide
http://www.hph.cz/304s_technical.php?&lang=en
Nigel Andrews
RF Developments Pty Ltd
"A Queensland Company devoted to Research and Development in aviation
electronics"
Email [EMAIL PROTECTED]
Web www.rf-developments.com
Ph: (61) 7 54635670 Fax: (61) 7 54635695
**DISCLAI
Looking for turbofans I found this interesting program at a NASA site - see
http://www.grc.nasa.gov/WWW/K-12/airplane/ngnsim.html
I think we should wait and see the 2 jet performance in Mikes set up though
I principally agree with Roberts thoughts, with over 400 hours in a self
launcher I never ha
At 12:27 PM 26/03/2007, you wrote:
So what is the cost of the engines you are considering Mike?
You can get an idea of engine cost from looking at the model jet
manufacturers websites.
Engine cost is only one factor in installation cost though.
Mike
Borgelt Instruments - manufacturers o
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