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When I hear about using the fuel as a heat sink, all I can think of is TWA 800.
Please be careful............... |
Mike, TWA went down because of fuel vapors exploding the center tank due to chafed wires arching. We won't have electrical inside any fuel tank! We also aren't looking at temperatures that will be close to boiling point or autoignition temperature.
We will follow your advice of being careful though!!!! |
Good, awareness was my goal.
Good luck with the project. |
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These are popular on race car stuff: http://laminovapro.com/ http://laminovapro.com/laminova-oil-cooler-information/ |
And
Many commercial aircraft use fuel to cool...things...
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One point seemingly overlooked here (and it might be me) is the fact that aircraft using fuel for cooling "stuff" are dealing with thousands of gallons and rely on huge thermal mass. There is very little "cooling" due to the airflow over the wings. The concept was explored quite a bit with wartime development and found unworkable for engine cooling. Seems to me that pumping a high thermal load into a small and rapidly diminishing quantity of fuel is a thermal runaway event in the making.
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Jet A boils at 375F, EGW boils at 230-250F. Both depending on the pressure of course, BUT the numbers - specific heat of Jet-A is 43% of water, and thermal conductivity is 17% of water. Both of which will drive up operating temperatures for the cooling system. It is certainly possible too cool this way, and we wont engineer within this forum, but it is quite different and having AES involved for the whole system is a real advantage. They will have access to data that is hard to get otherwise. |
The driving requirement seems to be a need for 130F fuel at injection delivery. The question is thus how to heat the fuel.
Having brainstormed a fuel-cooled system, sit down and map out system components with conventional coolant. Make a hard comparison. Fuel heating could easily be done via a simple tubular passage through one of the tanks on the water-to-air exchanger, just as transmission and engine oil is temperature regulated in automobiles. Very conventional, relatively safe, with high acceptance. |
And it would eliminate a 2gal 100psi-capable tank, the place to put it, and 2 lgal of unusable fuel.
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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 |
CI Version
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Thanks for your interest AH |
Benefits
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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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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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It seems your design is far superior to this. |
BSFC
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A.H |
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 he?s back and progress continues. He?s 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. He?s 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, it?s 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. I?ll 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 he?s working on, the production run of cases is complete and my case (#20) is complete. He?ll 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 it?s 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, I?m 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 we?re 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. I?m sure this sounds like other engines that have been saying it for a decade or more now. I can?t honestly say I know it won?t be true! I can say that Andy is still 110% committed to the success and production of the engine. I?m happy to see he isn?t 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! |
Any updates on this?
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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. |
Nothing really new to report. Oshkosh saw a lot of interest and a mock-up but the engine hasn’t run yet. Fingers crossed Andy is working hard and will run and produce once the design is proven and prototype is successful. I’ve been busy flying off my phase 1!
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andrew higgs project update??
I have emailed back and forth a number of times with Andrew over the past couple of years. I was also able to visit Andrew at Osh Kosh and I'm really looking forward to seeing him get into the production stage of his 4 cyl.
I sent him an email after the holidays but I have not had a reply as of yet. I'm guessing he is up to his eyeballs in all the tasks required to keep this project moving forward. Does anyone have any updates on the current status on the testing / certification / availability of his 4 cyl engines. I'm dying to get any info that anyone has.... Jeff Andrew if you happen to read this I'm the guy in Minneapolis with the motorcycles :-) |
Welcome to VAF
Jeff, welcome aboard the good ship VAF:D
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While I sincerely wish them all the luck and fortune in the world, just be aware how many promising developments over the decades have never made it to production. For over 15 years I believed the Zoche diesel was going to make it someday... :) |
I wouldn't be looking for a certified version any time soon. That process will likely take years more and many $$ more after prototypes run for some time and pre-production examples with all the final changes made get some serious testing time on them.
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just saw The HIGGS HAWK V4 E330J/G Diesel is taking orders.
is anyone putting one of these in an RV10? A. Mekler N668G |
Has the engine run yet?
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Tim just posted over on the RV-10 Facebook Group about the current status. https://www.facebook.com/groups/2496...962/?ref=share
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I Don't Facebook.............. |
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Definitely would like to hear more about this here on VAF, especially after the article in EAA Sport Aviation. I also don't use Facebook, so I'm not going to find it over there.
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Hi folks, I’ll do a quick update on here this week. Hang tight.
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Hi Folks,
So a quick update, Karl Grove has become the US representative and point person for AC-Aero. He's working hand in hand with Andy for the distribution and support of the V series engines. He has a wealth of knowledge and expertise that will really come in handy getting the initial production off the ground as well as setting up a support infrastructure. I will be working with Karl and Andy to still develop a firewall forward kit for the RV-10. My goal hasn't changed, to create a turn key solution including full documentation and support to install the Hawk on the RV-10. I'll do the initial prototyping and most of the testing on a test stand then hopefully transfer to my plane for flight testing once proven. At this time, I haven't gotten any further updates regarding the engine itself. I know Andy had some dyno time scheduled for late last year but I haven't heard any results. Covid really affected production in 2020 since he is in Japan, but things are opening back up. As I get confirmation the engine has begun testing, I'll definitely pass that along. Until then, I'm waiting patiently to get an engine in my hands so I can start integration tasks. Stay tuned! |
I am no longer affiliated with the development of a RV-10 firewall forward kit for the AC-Aero Diesel engine. More information can be found on their website. I will not be utilizing their engine but wish them the best of luck.
www.ac-aero.com |
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