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  #91  
Old 02-15-2019, 03:25 PM
rv7charlie rv7charlie is offline
 
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And it would eliminate a 2gal 100psi-capable tank, the place to put it, and 2 lgal of unusable fuel.
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  #92  
Old 02-18-2019, 07:51 PM
AC-AERO AC-AERO is offline
 
Join Date: Aug 2017
Location: Japan
Posts: 16
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Kaliber,

Some good work done in the past, "A stepped piston two stroke engine for high altitude applications"
Author Eran Sher and Michal Zeigerson.

Others from Hooper, which have been mentioned somewhere else on these posts.
And Peter (now Dr Hooper) have worked closely with me on these projects. Dr Hooper now works as a Prof at Uni

Andrew
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  #93  
Old 02-18-2019, 08:00 PM
AC-AERO AC-AERO is offline
 
Join Date: Aug 2017
Location: Japan
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Default CI Version

Quote:
Originally Posted by rv6ejguy View Post
Perhaps Andrew will introduce CI versions later?
We have had a CI version working for some time
Thanks for your interest

AH
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  #94  
Old 02-18-2019, 08:11 PM
AC-AERO AC-AERO is offline
 
Join Date: Aug 2017
Location: Japan
Posts: 16
Default Benefits

Quote:
Originally Posted by rv6ejguy View Post
After reading about the Hooper engine design and seeing the test results I find nothing stunningly advantageous over modern 4 stroke engines. Power to weight ratios are similar at similar rpms and specific output is also similar, perhaps 10% better for the Hooper in both cases.

The oil stays clean but you have to add more and change less. Parts count is less and that should mean it may be less expensive to manufacture in the same quantities.

The big disadvantage is that the BSFC figures are not very good, especially when operating on heavy fuels. Might be ok for a UAV, not so good for civilian users paying their own fuel bills.

It's an interesting concept. Will be interesting to see the test figures on Andrew's E-330 engine.
You are quoting data and products that were originally used to write the original papers.
Two strokes have notoriously poor fuel consumption due to "short circuiting" The papers you have read were based on engines that were using a simple carburetor for fuel supply.
As to benefits, well it is lighter, less parts has a positive torque output unlike a 4 stroke, which equates to less component stress and therefore smaller component design.
Compared to a 4 cylinder lycoming, we have 8 firing pulses per 720deg, so we have an inherently smooth platform
As to cooling, that is the subject of one of the Patents that I do hold, unlike Bill's statement that there were none.

I am delighted that the technology is stimulating the community and I look forward to answering you, assisting you all in the future. One slight caveat, I have three engine programs moving along at the same time and I might not be able to respond immediately.
Regards

AH
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  #95  
Old 02-18-2019, 08:16 PM
AC-AERO AC-AERO is offline
 
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Location: Japan
Posts: 16
Default Oiling

Quote:
Originally Posted by DanH View Post
From the Hooper UAV paper linked above:

....in a four-cycle engine all of the oil passes at some time into the high temperature region adjacent to the piston compression rings and is then returned to the crankcase...In stepped piston engines, however, this hot zone is lubricated by a simply metered small quantity of oil, on a total-loss basis.

Andrew, you there buddy? Upper rings are total loss lubrication? If so, how is it metered and supplied?
Dan,
I have been out of the country.
The piston oiling is almost identical to that of a 4 stroke engine with this iteration of engine. Cooling oil is fed from the crankcases to the under crown of the piston to remove the heat. Piston ring lubrication is the subject to a patent at this moment.

I have tried to answer a few posts this morning, if there is anything outstanding please do let me know and I will do my best to explain.

Regards

AH
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  #96  
Old 02-18-2019, 09:09 PM
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rv6ejguy rv6ejguy is offline
 
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Location: Calgary, Canada
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Quote:
Originally Posted by AC-AERO View Post
You are quoting data and products that were originally used to write the original papers.
Two strokes have notoriously poor fuel consumption due to "short circuiting" The papers you have read were based on engines that were using a simple carburetor for fuel supply.

AH
Actually section 7 of the report shows a predicted (but not demonstrated) BSFC figure of around .59 on Jet A using DI. Still nothing to write home about but a lot better than what the carb system delivered in testing.

It seems your design is far superior to this.
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  #97  
Old 02-19-2019, 12:09 AM
AC-AERO AC-AERO is offline
 
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Default BSFC

Quote:
Originally Posted by rv6ejguy View Post
Actually section 7 of the report shows a predicted (but not demonstrated) BSFC figure of around .59 on Jet A using DI. Still nothing to write home about but a lot better than what the carb system delivered in testing.

It seems your design is far superior to this.
I don't understand the relevance of quoting somebody else's work? This paper and work has nothing to do with the work that has followed and been completed by this company. We will be reporting our findings when we release the engine data.

A.H
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  #98  
Old 05-05-2019, 09:51 AM
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majuro15 majuro15 is offline
 
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Posts: 621
Default May 2019 Update

I wanted to give a short update on the Hawk V4 engine for everyone following along. Quite honestly, I have been too busy working and building so haven't gotten much information out to you all lately. Andy has been out of the country (Japan) for several months working on a few other projects including the V12, so progress on the Hawk has slowed a bit. All hands are on deck now since heís back and progress continues. Heís requested a few components be reworked by the casting company as he had some fitment issues that did not meet his standards, so that has slowed the initial build up. Heís got the cylinders being touched up on the CNC now after recasting them and will be fitting the revised components next week. Needless to say, these things happen when producing a clean sheet design. While it is disappointing that the extra time must be taken, itís comforting to know that the extra time is being taken! Andy is not compromising his standards to rush a product into the air. Importantly, the issues are minor and related to getting the manufacturing tooling setup, not anything with design of the components.

He is pressing hard to get a working engine to OSH for display in the innovation tent this year. Iíll be in OSH Saturday (pending WX) through Tuesday afternoon and will try to spend most of the day Monday with Andy in the tent to talk with folks about what we are working on.

While the case pictured (coming soon, I'm at work and can't post it) is still a prototype case heís working on, the production run of cases is complete and my case (#20) is complete. Heíll begin running the engines once he is happy with all fitting and initial build up is signed off, hopefully in the next two months. Build up of the drive train is well underway and is progressing smoothly. This is a bit behind his original schedule.

After a lot of discussion and thought, I have decided to order a Lycoming for my RV-10 build and proceed with getting my airplane airborne. I made this decision based on two main factors, one financial and one personal. I am using a construction loan for the last part of my build and it is interest only payments right now. It also has a construction time limit of 18 months, so I am under a timeline that I must meet to avoid large financial penalties. Thus I could not wait any longer to get an engine on order nor did I want to put pressure on Andy to get the engine flying before itís tested and proven ready. The personal reason is to get our airplane in the air so we can start utilizing it soon without the pressure of integrating the V4 on it before it flies. I really want to get some adventures going with family and friends!

So, I have reworked my approach to the V4 which will ideally make it a more enjoyable and less stressful project! I will be creating a test stand based on the RV-10 firewall and Show Planes cowl to create the firewall forward package for the Hawk. This will let me have a bit more freedom to make initial adjustments and some mistakes without it impacting my flying airframe. It also takes the personal pressure off of me to get the Hawk flying sooner since I can still go fly my 10. Once the engine mount is finished being machined, Iím going to start fitting and locating the systems and support components to prep for the V4 arrival. We will get a full setup going on the test stand and be able to really iron out the details along with creating documentation for those who select the Hawk for their builds. Andy has been really supportive of this decision and I appreciate his advice on this. He wants a seamless transition to using the V4 and if it takes a bit more time, so be it.

Once this tests rig is complete and weíre happy with the package, I will convert my airplane to the V4 and document that as well to create a firewall forward package which will be made available to other builders. The test stand will ideally stay in use for demonstration, testing future updates, and marketing at events.

Iím sure this sounds like other engines that have been saying it for a decade or more now. I canít honestly say I know it wonít be true! I can say that Andy is still 110% committed to the success and production of the engine. Iím happy to see he isnít compromising on quality and wants to see folks use his engine safely and reliably.

Stay tuned for another update around the end of the month. In the meantime, keep building! I finished my doors, windows, and now have avionics powered on. I hope you all are well and look forward to seeing you at OSH this year!
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  #99  
Old 11-16-2019, 11:24 PM
Volzalum Volzalum is offline
 
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Any updates on this?
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  #100  
Old 11-17-2019, 07:57 PM
Andy_RR Andy_RR is offline
 
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Quote:
Originally Posted by rv6ejguy View Post
Neither the Hooper or E-330 are diesels, they are heavy fuel capable, SI designs. I am confused...

The Hooper engine has dreadful BSFC- especially on Jet A.
Just spotted this thread. Interesting engine design!

This range of BSFC is typical for smaller engines used in UAVs. As power levels drop BSFC gets worse due to thermal efficiency effects of worsening surface/volume ratios.

I was heavily involved for a time on a SI heavy fuel engine for a Scandinavian UAV helicopter and we saw a best effort of around 300g/kWh on JP8 and Jet-A1 for about 55kW. SI on heavy fuels isn't an easy problem to lick due to the poor and generally uncontrolled octane rating of the fuel. On the up side, two-stroke engines can tolerate a lot more knock intensity than a four stroke given the much lower cylinder pressures.

Anyway, I wish Andrew well in his endeavors! It's a challenging project in many areas.
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