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  #31  
Old 01-11-2019, 10:46 PM
AC-AERO AC-AERO is offline
 
Join Date: Aug 2017
Location: Japan
Posts: 16
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Yes you are absolutely correct, when I retired from F1, I thought this would be easy however the more I became involved, the more I realized just how complex a simple engine can be
I had to go on a steep learning curve, but thankfully I am on top of it, but make no mistake, aviation engines are simply amazing, take time out and look at how the parts for the engines were made years ago before NC machines, hats off to all those brilliant engineers and incredible shop floor Guy's and Gal's who could produce those wonderful parts for radials and the V12's we all love
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  #32  
Old 01-11-2019, 10:59 PM
AC-AERO AC-AERO is offline
 
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Location: Japan
Posts: 16
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Bill I sent you a reply asking you to clarify your comment about the "poor" frictional issues. I have just come off the dyno with a client and in fact the the FMEP is lower than any engine we have tested to date. Whilst the pumping piston does increase pumping losses and increase friction, this is offset by the fact that these engines do NOT have any valve train rockers or cams to drive.

Andrew
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  #33  
Old 01-12-2019, 07:42 AM
BillL BillL is offline
 
Join Date: Sep 2007
Location: Central IL
Posts: 4,948
Default New data - exciting and sometimes confusing!!

Quote:
Originally Posted by AC-AERO View Post
Bill I sent you a reply asking you to clarify your comment about the "poor" frictional issues. I have just come off the dyno with a client and in fact the the FMEP is lower than any engine we have tested to date. Whilst the pumping piston does increase pumping losses and increase friction, this is offset by the fact that these engines do NOT have any valve train rockers or cams to drive.

Andrew
That is outstanding, Andy, the modern rings must be part of that equation too. I was speaking from a generalization, and that is always dangerous to compare to real life. Yes, the pumping losses are higher, not much available to avoid that, but elimination of a blower for starting to force the beginning of the process is a huge weight saving not to mention friction and pumping losses for some operating conditions. Then there is that thorny heat of compression to deal with . . .

Regarding the expansion ratio, my comment was based on many simulations with piston port valving. (I don't recall the stepped piston design specifically) Where it takes some physical stroke to uncover the port on the expansion stroke. Without 3000 psi PCP capability it is not likely to eat much efficiency, but will definitely have its effect. It might be an advantage for turbocharging, though recapturing the blowdown energy.

Does your stepped design allow tailoring the intake timing to allow a shorter stroke than the exhaust stroke? I am not sure that is even possible as blowdown pressures on 4-strokes can be 50 psi.

All this is moot now with test data coming in. Decades ago I did a tour of Hino, Isuzu Diesel, Toyota, and Mazada, then later worked with Isuzu quite closely. All on diesel designs for low particulate emissions. There are some outstanding diesel engine design engineers close to you!!. The Hino guys were really impressive, as was the designer at Isuzu (Duramax), very free thinkers. All long gone by now, but surely succeeded by people just as capable.

I assume you are using common rail fuel injection? It is the holy grail for multi fuel capability with its ability to rate shape the injection charge and do a pre-injection for control of cylinder pressure rate-of-rise issues.

Best of luck with development, and keep us posted on results. My PM-email works here.
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RV-7
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  #34  
Old 01-13-2019, 05:57 PM
AC-AERO AC-AERO is offline
 
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Location: Japan
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Bill, thanks for your compliments. One thing that seems to have escaped your observation, my engines are NOT diesel C.I engines, they are two stroke Spark Ignition, burning JET A
Andrew
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  #35  
Old 01-29-2019, 09:45 PM
Teej Teej is offline
 
Join Date: Dec 2018
Location: Milwaukee, WI
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Just following up to say I'm interested and I love the development.

I'm soon going to throw a post up in an appropriate forum about my history and why I'm here, but I truly am rooting for a viable alternative!

Teej
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  #36  
Old 01-30-2019, 11:24 AM
BillL BillL is offline
 
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Location: Central IL
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Quote:
Originally Posted by Teej View Post
Just following up to say I'm interested and I love the development.

I'm soon going to throw a post up in an appropriate forum about my history and why I'm here, but I truly am rooting for a viable alternative!

Teej
Welcome aboard, Thomas!
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Bill

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1st Flight 1-27-18
Phase II 8-3-18
Repairman 11-15-18
Instrument Currency 12-17-18
Shrunken Exit = ??
No Photo? => PM me.
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  #37  
Old 01-30-2019, 12:04 PM
woxofswa woxofswa is offline
 
Join Date: Sep 2007
Location: Mesa Arizona
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I love the new tech and innovation and wish everyone involved the best of luck.

One quick point of reference. A comment was made about 100ll in Mexico.
It just so happens that for the past two weekends, I have flown my 10 to Mexico. Baja for a Samaritan’s trip, and mainland for a Copper Canyon railroad trip (fantastic). We found Avgas readily available and if we averaged the cost in dollars per US gallon, it would come out to less than $4.00 USD (paying cash in pesos.). Buying with a US Credit card would be slightly higher but still less on average than stateside.
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  #38  
Old 02-04-2019, 04:51 AM
Kalibr Kalibr is offline
 
Join Date: Aug 2015
Location: St John, Steamboat Springs, planet Earth generally
Posts: 81
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Dear Andrew, fair winds to you, sir!

With limited success, I’ve been trying to pierce together some info to understand the techical aspects of this engine. Is there somewhere I can read on it? I am not an engineer.

From what I gather, it is a two cycle engine where on the expansion stroke the firing piston charges/pressurises the next cylinder and so forth. Am I correct?

I wouldn’t think a discussion of the basic mechanics would infringe on Andrew’s proprietary know-how.

Thanks!
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  #39  
Old 02-04-2019, 06:30 AM
BillL BillL is offline
 
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Location: Central IL
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Quote:
Originally Posted by Kalibr View Post
Dear Andrew, fair winds to you, sir!

With limited success, I’ve been trying to pierce together some info to understand the techical aspects of this engine. Is there somewhere I can read on it? I am not an engineer.

From what I gather, it is a two cycle engine where on the expansion stroke the firing piston charges/pressurises the next cylinder and so forth. Am I correct?

I wouldn’t think a discussion of the basic mechanics would infringe on Andrew’s proprietary know-how.

Thanks!
This site has the best explanation of the basic concept. They have been around for many years. http://www.bernardhooperengineering.co.uk/opads.htm

I could not find any US patents under Andy, but found several for the Hoopers. Peter Hooper is a PhD and did much on this engines analysis.

It is a relatively low compression, I am assuming due to the piston porting. I am not sure how it gets lubrication for the upper piston rings or what the pumping ratio is from the stepped to the primary combustion chamber. Reed valves prevent back flow. It would make a quite wide engine opposed configuration compared to a standard 4 cycle due to the long piston but the V config can package nicely. Should be very smooth, although at a little disadvantage for efficiency. Its main advantage is smooth, light, and fuel tolerant.

It needs about 10,000 hours of field operation work to prove out.
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Bill

RV-7
1st Flight 1-27-18
Phase II 8-3-18
Repairman 11-15-18
Instrument Currency 12-17-18
Shrunken Exit = ??
No Photo? => PM me.
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  #40  
Old 02-04-2019, 10:29 AM
Kalibr Kalibr is offline
 
Join Date: Aug 2015
Location: St John, Steamboat Springs, planet Earth generally
Posts: 81
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Bill, thank you for the lead!

Here is a link to a paper providing a more detailed overview than the website: http://https://aut.researchgateway.ac.nz/bitstream/handle/10292/6846/P%20IMechE%20Propulsion%20Systems%20for%20UAVs%283 00NA%29.pdf?sequence=2

There is an explanation of the lubrication system. The hot/working part of the cylinder/piston is lubricated on a total loss basis.

That is on the Hooper engine. Andrew’s engine might be different, of course
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Last edited by Kalibr : 02-04-2019 at 10:52 AM.
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