aim

Please help on 4 Stroke Diesel fuel consumtion information and experience..

Any one have figure and links concerned fuel consumtion of the 4 stroke diesel.
Please give comparison figure for the same size in Glow and Gasoline

I think, Diesel won the reliability in theory and very much so to the practice.

The next issue is fuel efficiency. If it can win the gasoline engine like the DIESEL ENGINE in the AUTOMOBILE industry or not.

One of the best in it's class Model Gas Engine is in the following Google links belong to Aerosonde
Gasoline modified fuel injected Enya 23 cc. .......first Aerosonde flight to witness 2 sunrises.
Fuel consumption during the mission ranged from 207 down to 122 gm/hour

http://www.google.com.au/search?hl=e...mption&spell=1

Also another good UAV project select Enya 53 converted to gasoline very low consumption, still under developing.
http://www.albatross-uav.org/index.p...sion2:Airframe
gasoline fuel - premium 96 octane unleaded - with about 5% oil (we made end up needing slightly more)
run it at about 4500-5000 rpm, burning about 65 g/hr (density of gasoline is about 0.73 kg per liter, so about 90 mL/hr)

Please help to give info if we have any other info to compare and start working on it at least
making Model Diesel closer to that gasoline competitor.

Perhaps,

1. fine tune 4 stroke Diesel coverted-Glow fuel inject engines that are avialable now -
for example FS-91S11-F1 (60T) W/F-4020 SILENCER
FS 200S FI FUEL INJECTED FOUR STROKE
or other 4 storke fuel injected ........ please suggest others....

2 or put fuel injected system to the existing good Model Diesel..... Will it help?
Please have a look at http://www.albatross-uav.org/index.p...sion2:Airframe ,
on the part of fuel injection system in lower part of the page.

3. If we change Enya 53 to diesel instead of converted to gas... any one has info or comment.

Please share your experience and info.

Thanks everyone in advance

Edit on 9/April/2007 aim

AMB

Aim it was running on coleman fuel ignition of course , looks like an average of 10 minutes an oz I do not think you would do any better if the engine was 91 or larger you might be able to equal that you do have a lilttle more BTU in kero than white gas but that thing was maxed out for fuel economy. I do not remenber the engine size 120?? martin

gkamysz

My Feedback: (19)

The fuel consumption figure is rather useless with a power figure attached to it. Normally you would do it like this http://en.wikipedia.org/wiki/BSFC or http://en.wikipedia.org/wiki/Specific_fuel_consumption.

I flew my FS-48 diesel at full throttle ~0.6kW for 25 minutes on ~125g of fuel mix. That's 300g per hour at ~0.6kW output or 500g/kWh. That includes the 20% oil in the fuel. If you could eliminate the need for oil in the fuel that would be 360g/kWh.

I don't think a model diesel could do much better than what was used in that project. A lot of development went into that. It is fuel injected and should be able to do things you just can't do with a carb.

ama1836

I have had 6.3oz/ hr consumption on an OS.91 converted to spark ignition with JP8 fuel and 50:1 Amsoil. This if flying a 20+ pound aircraft with a commanded airspeed of 21-23 m/s.

aim

Dear ama1836

1. please confirm if OS .91 is FX RX or what ?
2. if anyone had converted OS .91 to diesel and have fuel consumption with power reference as gkamysz and ama1836 presented.

Dear Dieseldan

I update my original post with more details Arosonde use gasoline not coleman fuel.

Thanks u all
aim

gkamysz

My Feedback: (19)

Though not obivous, it should be apparent that the engine Ama1836 used was a .91 FS four stroke. If fuel efficiency is the goal, you would certainly start with a four stroke.

ama1836

Yes the engine was an OS.91 four stroke the mods were simple and included a carb and intake assembly from an OS .?52 Four stroke and a sincrospark from c&h with a NGH spark plug. The prop was and APC 14x8 which indicated 5,800+ rpm on the ground and up to 6.700 in the air.
Steve

aim

Dear Ama1836

Thanks here again for your info.
Please help a bit more.

1. Is your OS.91 is Surpass 11 4stroke?
2. Can you give before gas conversion fuel consumption? -- for comparison.

And to all the diesel Guru

3. Has anyone convert OS .91 4stroke to Diesel before?. If so, how is the fuel consumption?
(please do not forget to include surronding conditions).

4. I got from a few post that diesel will use half of Glow consumption. Does it mean if Ama1836 or someone has Glow consumption on .91 4st, then we can roughly compare Glow consumtion/ Quessed Diesel consumption / Ama1836's Gas consumption 6.5OZ(183gm?)/hour ?

Thanks you very much
Aim

ama1836

With the same airframe we could fly for 3 1/2 hours on 80 oz of fuel which equals 22.8 oz/ hour. This was repeated several times with similar results. I must also say for the diesel figures the aircraft was simply flying a racetrack pattern at a consistent altitude while the glow was done at different commanded altitudes and airspeeds.
Even with equivalant flight paramiters I would expect no better than 12oz/hour.
There is a site where people have made OSFS engines into compression ignition. When I find a link I will post it.
Steve

ama1836

http://www.rcuniverse.com/forum/m_90.../tm.htm#900816

Look at this forum. Its really close to where we are now.
Steve

gkamysz

My Feedback: (19)

Aim, I think you are getting into a topic which most people would charge money for. We both know that in the UAV business such information has value. Most people here don't have the kind of information you really need any way. You are really getting into a development project and that will cost money.

I have a converted FS-91. I have just a few minutes of runtime on it.

What is the reason for your choice of diesel for this application? If it's simply fuel consumption the project is much simpler done with spark ignition like Steve does in his engines.

ama1836

I was the Sr. UAV Technician at Advanced Ceramics Research. They did spend much time and money developing a heavy fuel engine and have since changed to gasoline with a converted Honda GX25. The reason behind the Diesel (JP-8) is the militarys upcoming for a single fuel, which will be Diesel/ JP-8.
With a spark ignition it is possible to convert almost any "model" engine to heavy fuel. A good starting point for carburation is 1/2 the inlet area and tweek it from there.
Steve

aim

DEAR GREG

I really like diesel in theory. It has less parts to worry, especially electricity.
If the fuel consumption can be made close enough to Gasoline engine, I will favour diesel.

I am a very small bussiness. Want to develop cheap UAV so it can be used for the forestry survielance in the developing world.

It is the dream. I don't see much money at all, mainly, hope to protect the environment.

I haven't got the money to do expesive research, and hope that the forum like this will help the project.

We are in a process to get Diesel head for our OS.91.

But keep looking for alternatives. Including converting 0S.91 to Gasoline, to compare the out come.

I will soon start reseaching on gasoline. But would like to learn more on diesel still.

THANKS ALOT FOR ama1836 for the info too.

aim

ama1836

There is more energy available in diesel than gasoline by about 13% sou you should get better energy. If you have any questions about UAV's please ask. I'll answer what I can and direct you to more information where appropriate.
Steve

NM2K

My Feedback: (14)

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We should keep in mind that our model Diesel engines are not Diesel engines in the same sense as direct injection full-size Diesel engines. It would be unrealistic to expect the same type of performance from our model Diesel engines as can be obtained from the much more technically sophisticated full-size Diesel engines.

This is not to say that examination of the model Diesel engine is not merited, but it is well advised to buffer our expectations a bit.


Ed Cregger

ama1836

But there are currently made direct, mechanical injection compression ignition engines. Along with several people/ companies developing throttle body injection units. In both HP and Comsumption vs weight "model" engines are better than most industrial engines. Besides it is hard to fit an industrial engine in an RC airframe ;-)
Steve