Gemini 100 Diesel Engine

[matto]

Came accross this interesting engine, not sure if it has been posted before, here are a few links

 

http://ppdgemini.com/_PDF/Gemini100_Spec_Sheet.pdf

 

http://ppdgemini.com/

 

http://dieselair.com/2007/07/powerplant-developments-in-uk-unveils.html

 

 

[hiperlight]

The Rootes Group Commer TS3 'Double Knocker' from the 1940's until the 1970's was similar in design to the Gemini 100 except for the single crankshaft and substantial rockers.

 

http://www.oldengine.org/members/diesel/technical/TS3.htm

 

Bruce

 

 

[facthunter]

Opposed piston. diesel.

 

This design offers a lot of advantages, including the elimination of the troublesome head gasket joint and very good balance. The commer design would have had some advantages over the 2-crankshaft design (essentially Junkers Jumo). ie.assymmetric timing, much easier to service, less sideload on the pistons, narrower, no need for a 4- gear connection between the two crankshafts, (though both would require a reduction set-up, the two crankshafts would "fight" each other by being linked by a gear train. Maybe there are still patent considerations applying to the Rootes design. Nev.....

 

 

[hiperlight]

A classic example of two linked crankshafts 'fighting' one another was the Ariel Square Four.

 

Another interesting opposed piston diesel was the Napier Deltic used in Motor Torpedo Boats in WW2. Three crankshafts set up at the apexes of an inverted triangle with three cylinders and six pistons between, in each bank.

 

General Motors bought the rights to that engine in the 1960's (I think), and converted it to steam as an exercise to prove that steam power was not a practical alternative to their 'gasoline' guzzling V8's. GM has, I believe, archived it for the 'future'.

 

Bruce

 

 

[FlyingVizsla]

Gemini Engine on order

 

We placed an order for the Gemini diesel engine with PowerPlant Developments in the UK. Last we heard the proptotype was undergoing endurance testing. Once proven it will go into production and be shipped (optomistically - early 2010). Will keep you posted on progress.

 

Sue

 

 

[Vev]

Hi Sue,

 

Sounds like a very interesting engine?

 

Whilst I know it's a diesel, but what fuel is recommended by the manufacture? The reason I ask, is I would have huge concerns about the use of diesel fuels in Australia if diesel fuel was being considered.

 

Cheers

 

Jack

 

 

[kaz3g]

Hi Sue,Sounds like a very interesting engine?

 

Whilst I know it's a diesel, but what fuel is recommended by the manufacture? The reason I ask, is I would have huge concerns about the use of diesel fuels in Australia if diesel fuel was being considered.

 

Cheers

 

Jack

Hi Jack

 

Diesel supplied here varies as to the season and is high in waxes. The Gemini will run fine on Jet A1.

 

Try Gemini Engine for more info

 

kaz

 

 

[Guest basscheffers]

The reason I ask, is I would have huge concerns about the use of diesel fuels in Australia if diesel fuel was being considered.

What would be the problem?

I know one school at Parafield refuels their DA42s from their own Diesel trailer rather than getting Jet-A from one of the suppliers on the field. They don't seem to be having problems or they wouldn't keep doing that?

 

 

[Vev]

Hi Kaz,

 

 

Completely agree with your comments about wax – cloud point of diesel fuels, in fact it’s more complicated as it varies geographically as well as seasonally.

 

 

What caught my attention was in the manufactures spec sheet, it said “Diesel/Jet A1” .. of cause Jet A1 won’t have the same issues and think this would be a better choice to avoid waxing.

 

 

Basscheffers,

 

 

The problem is Diesel Fuels vary considerably between seasons and region … to give you an example .. if you fill with Diesel, lets say March in Townsville, you will find the cloud point to be 11 deg C … if you then fly to south to Brisbane the max spec for cloud point is 3 deg C for the same period. If you delayed your flight until April the max cloud point is 0 deg C for Brisbane. Therefore the risk is about purchasing diesel fuels in warmer climate and flying into cooler geography/seasons as you may be at risk of fuel turning into wax in your fuel lines … not to mention the risk of fly high and cooling things off.

 

 

Jet A1 has a very low cloud point and should never be an issue with the type of flying we do.

 

 

Cheers

 

Jack

 

 

[FlyingVizsla]

CASA has not approved diesel fuel for use in aviation AFAIK, so the alternative is Jet A1. This engine is to replace our AVGas engine.

 

It is getting harder to get Avgas - our last flying holiday was cut short when we could not source a drum - no one in town or surrounding towns could sell us one as they had to be licenced. We thought this was to stop terrorists buying fuel and pinching a plane - No - it is to stop hoons using it in drag racing (so the fuel merchant said). Anyway, faced with a 400km round trip and stat dec to get another drum we went home. Greenies regard AvGas as worse than other fuels for pollution and it is hard to source overseas - see some of the London - Aust air race/safaris blogs, web sites. India is particularly a problem.

 

At our airstrips without a fuel bowser the fuel depot brings out a drum and once opened the remaining fuel can't be used for another aircraft and the drum cannot be returned. It is getting very impractical, not to mention expensive where you have to buy 200 litres to get the 50 for the plane and leave 150 behind that no one can (legally) use. Old drums cannot be refilled, so we have a collection of them.

 

Power Plant Developments say the Gemini will be capable of using biofuels. Would also be handy way outback where there is always diesel, but not always petrol or aviation fuels. We have a lot of experience with diesel engines in other applications so we decided to pursue one as a means of future proofing at least one of our aircraft.

 

Sue

 

 

[Vev]

Hi Sue,

 

 

Thanks for the feedback … I can relate to your problems of accessing avgas through personal experience. Over the past few months there have been a number of fuels storage facilities removed around the country. Shell walked in a few months ago and dropped a bomb shell on our club and said we can either buy the facility or they will rip it out. Fortunately we managed to negotiate an acceptable deal and bought the tank and pump set up… we also have a new supplier who has given us a better deal too.

 

 

Your new engine sounds like an interesting project and look forward to hearing how thing progress.... good luck with it all.

 

 

Cheers

 

Jack

 

 

 

[Guest basscheffers]

Jack, I always wondered about that; I remember as a kid, Diesel fuel on cold winter days in the Netherlands could be a problem. I was never sure what they'd done about that for Diesel engined aircraft, which fly cold regularly simply by going up high...

 

Sue: looking at the list, are most of your aircraft not capable of running on MOGAS? In fact, wouldn't your Rotax powered ones not be a lot better off on it?

 

 

[HEON]

Getting Avgas is a problem and it's getting worse we know.

 

Another aspect not written up is the remaining facilities are now more often on bigger airfields and often in controlled airspace which we as RAA pilots should not enter. Very hard not to go into Alice Springs or Tindal if in that part of the world for fuel. Yes I know Tindal is CTAF outside TWR HR but it can change quickly...happened to me while on the ground...made the departure "interesting", but another story.

 

While the use of Mogas is an option in Rotax and Jab the only avalable Mogas in a lot of Central Australia is standard...which to the best of my knowledge is only suitable in Rotax 80hp!

 

 

[Yenn]

Aue. I have been refilling Avgas drums for about 7 years. They give them a once over and if OK I refill them and take them home rather than have to run the plane to Gladstone to refill. Do you have spare drums at Childers, I could always do with another one. You can get fuel at Bundaberg, they have a carnet card facility for Shell.

 

 

[Guest basscheffers]

I have been refilling Avgas drums for about 7 years.

Our friendly local refueller has no issues with it either. They won't take them back and swap them for full ones, but plenty of people show up with their drums on a trailer and they refill them in the yard right from the truck.

However, that doesn't solve the problem of asking them to drop a new drum at a station for you on your trip...

 

 

[FlyingVizsla]

I used to run my C152 on Mogas (when Avgas was dearer) but had too many problems with vapour lock in the hotter months - I was in outback Qld with days in the 40's and tarmac hotter than that. Husband does not like Mogas in his engines. We are limited by the types of fuel available in town and now cannot refill drums with anything - The Council stopped that practice under the Trade Waste banner because they maintained that any fuel that got spilt from drum refills could run away to end up in the creek 1km away and get washed down when it next ran.

 

We could get Avgas at an airport bowser, but neither of us have an ASIC and the nearest airport to where we had the plane is listed as a secured airport even though it does not have a RPT anymore. An ASIC is required to land, refuel and depart. Only the plane can be refuelled, no containers, drums etc. Bundaberg was the nearest we could get a drum of Avgas and we needed a statutory declaration to say we were pilots and the fuel would be used exclusively in aircraft. Fuel merchants must be licenced to sell Avgas, we thought this was all to stop the terrorists but it is actually to stop the hoons putting Avgas in their drag racers. Avgas is planned to be removed as a fuel because of its lead content, inefficiency and polluting byproducts.

 

The Avgas drums cannot be reused and once opened the rest of the fuel cannot be used. Hence fuel merchants have to charge for the full 200 litres plus the drum and suspect a mark up to cover the licencing and compliance issues. A few years ago cockies used to pull up alongside the fence and get the refueller to poke the hose through the fence and refilled their drums (can't take a vehicle airside) - then the Council decided it was a security breach and stopped the practice. So you can only get it in drums from a fuel depot.

 

The drums are beautiful; new, lined, non returnable and take up lots of space. If you collect 4 they make good legs for a workbench to build another plane. And you can keep pointing out how you need more workshop.....

 

Sue

 

 

[Guest basscheffers]

Sounds like the main problem is your council. Would it be worth getting the airport users together and letting a magistrate decide on the issues? The council clearly has no idea about either health and safety or security, other than the tired and tested rule of "inconvenience = safety". Or do they just want to get rid of the field altogether and any excuse will do?

 

I am surprised your hubbie prefers Avgas even in the Rotax. My understanding is they will seriously foul up (especially on the green stuff) and few that run exclusively on Avgas make TBO without needing a top-end. That's why I run mine on PULP now.

 

 

[Keith Page]

photos

 

Here are some photos of the gemini when it was at Oshkosk 2008.

 

 

 

 

 

[FlyingVizsla]

Hi Basscheffers,

 

It is not one Council, but 3 different recently amalgamated Qld councils. Once they get big it seems covering their backsides against even the most unlikely mishap becomes the high priority and serving the community (especially the smaller towns) drops off the radar. The difference, I think, is that elected Councillors on small councils were aware of issues and were proactive in raising them at meetings, they looked at things almost on a case by case basis. The larger Councils have these things decided by the bureaucracy and Councillors many never know a request & response has been made.

 

One example - the small Shire covered about 23,000km2 of mainly farming land, a popular National Park, with 2 small towns, one doctor & a small medical facility meaning nearly everything, from a broken bone upwards was evacuated to a larger facility. Realising the community benefit and cost to owners the small Council directed that when a Council grader was in the area that they grade the RFDS designated private strips. Owners were already contributing flares and their time and SES, volunteer ambulance bearers etc etc to see an injured tourist or resident to safety. Then comes the big Council. "Liability, cost, core function, etc" and the bureaucracy decides to stop the practice. Because that decision is within established policy the issue never gets to a meeting.

 

The attitude now - if we were all good citizens we would operate from the major airstrip with our ASIC cards, paying aircraft parking, car parking, landing fees and refuelling from the airside bowser. That airport made a profit of over $1Mil and then they bought in car parking fees and raised others. Same Council was making noises about unprofitable small strips.

 

Unfortunately there are not enough of us to make a dent in the behemoth.

 

Sue

 

 

[Vev]

Hi Sue,

 

 

May be not much help to you in Childers, but something to keep in mind (if Mogas is approved for your engine) and you are having vapour lock problems with Mogas in remote hot areas. Opal fuel is a Mogas 91 RON product but has basically the same chemical volatility profile as Avgas without the lead.

 

 

The low volatility is why it can’t be used for petrol sniffing and was introduced by the Government in remote areas where they had a problems.

 

 

However do make sure that Mogas is approved for your aircraft and do your own research (check with oil companies) and satisfy yourself about the suitability.

 

 

Cheers

 

Jack

 

 

[Kyle Communications]

Any update on the Gemini 100?...I happen to find it on a 2007 video on youtube and after doing a google search found this link on RAA forum...so does anyone have any further on this interesting option

 

Mark

 

 

[FlyingVizsla]

Last real news we had was in a USA magazine (Kit Planes?) that listed engines and noted that it was due for release April 2011. We had rung months ago and were told that it was in endurance testing. We had put a deposit on one, well knowing that it might varpourise with the whole concept, but at least it will help build the knowledge to ultimately get one to market. All the news on the web is old stuff. I guess the GFC knocked them around as they are UK and USA based. Heard a rumour that Powerplant Developments had been sold, but couldn't find anything. We have phone numbers for the major players, but figured we would not hassle them until nearer to April.

 

Sue

 

 

[Kyle Communications]

Hi Sue

 

yes I have done a fair bit of searching today after I found it and its only all old stuff. Its a pity there isnt more info as this could be a way of the future especially for fuels...biodiesel can be made at home and diesel is a lot easier to get out west. Are you based in Childers?. I dropped into Childers airfield this morning on the way back home from our property up that way to see if there was any action but only person there was the guy who has the drifter and has just moved from Gladstone area I had met him there previously.

 

Mark